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UnderneathTheRadar
12th May 2014, 20:22
In all of the discussions around various diesel alternatives, my money has always been on these guys. Up until now have very much flown 'underneaththeradar' but now have something to show for it all.

First test flight last week in a Cirrus with Dick Rutan at the controls. This one is the game changer for commercially operating big twins and remote area 206/210s.

EPS | A Revolution in Flight (http://eps.aero/)

27/09
12th May 2014, 20:50
Looks a very nice setup. It appears even the radiator is contained within the engine cowl, it looks like it's fitted on top of the engine.

Perhaps the new metallurgy being used is the quantum step required to make a leap forward in piston engine aircraft design.

Having said that the website is a bit light on specifics, so it's hard to make a really informed assessment.

Certainly looks as if it could be a viable replacement for the TSIO and IO 540 and 520/550 engines.

The only concerns I have are:

1: What size market do they need for it to be a commercial success?
2: Will it fit inside existing cowls using the same mounting points on the firewall?

Do they intend to make an engine for the masses, by that I mean the O 320, IO 360 market.

UnderneathTheRadar
12th May 2014, 21:59
Purely my guesses:

1. Yes - their main market is actually looking like drones - predominately for the US DOD.
2. It took them a few weeks to attach it to a Cirrus which seems pretty good for the first time it's been near an aircraft - if you look at the various test videos you can see it's usually mounted on aircraft-type mounts and it's been vibration tested by Hartzell - again on aircraft-type mounts. It has been specifically engineered to fit inside existing cowls (they have done this by literally measuring a variety of engine bays). Remember this has been engineered from ground up as an aircraft engine and not adapted from another application type.

They are planning to manufacture about 500 year. At the moment, the first available slots in the schedule are in 2017 assuming it gets STCd next year. All slots ahead of that are gone.

Whether or not its a replacement for the smaller market - I suspect not. It will be expensive (the idea being that it pays for itself in longer TBO, lower fuel consumption and/or operating at max continuous whilst not at full rich) and so probably not an option for aircraft operating less than a couple of hundred hours a year. Once proven though - it could be scaled down - the current unit is capable of 450HP (I think?) and so will be de-rated for many applications anyway.

Oktas8
12th May 2014, 22:12
The website is a beautifully crafted piece of advertising. Nothing wrong with that of course, but it's in the same league as a glossy brochure for any new product. Heavy on promises, light on evidence.

TBO 3000 hours is interesting. If it actually achieves that, it could become very popular. Vibration and fatigue-related issues prevent that kind of TBO with other diesel engines - particularly Diamond's otherwise very good engine. This leads me to the question: what do they know, that Diamond don't? Perhaps something, perhaps nothing...

Andy_RR
12th May 2014, 23:59
No mention of weight comparison. I suspect that with an iron block and eight steel pistons, it's not going to be a pretty number.

27/09
13th May 2014, 00:50
Andy RR: No mention of weight comparison. I suspect that with an iron block and eight steel pistons, it's not going to be a pretty number.

Apparently the iron block isn't heavier according to their blurb.

EPS | Reliability, Safety & Durability (http://eps.aero/the-eps-engine/reliability-safety-durability/)

The Graflight V-8 engine derives its name from this key component. CGI is an advanced material that offers extraordinary strength and fatigue resistance, allowing CGI blocks to be made lower weight than equivalent strength aluminum blocks. It was first patented by a German scientist in 1965, but in 2008 an American engineer, Dr. Steve Dawson, first wrote about using CGI in modern diesel engine cylinder blocks and heads. EPS CEO Michael Fuchs was among the first to employ CGI in the automotive field in America. It has since set the standard in the industry because its high tensile strength provides extraordinary durability. Aluminum aviation crankcases often crack from fatigue – a common point of failure in GA airplane engines. But the Graflight V-8 block offers incomparable durability, and will be able to serve far longer between maintenance overhauls as a result.

Ixixly
13th May 2014, 00:52
I think the part that would concern a lot of operators, especially Bush Operators is the level of Electronics that is seems to employ to control it, I know a few Engineers that would bring up this point straight away. The more complex you make something the more there is that can break down and the more parts you need to keep instock to keep it flying or get it back in the air! One of the reasons so many people think of Diesel Engines as being a great introduction to their Aircraft would be because of their reputation as being reliable engines elsewhere, but I know from a few Diesel Mechanics that this is because of their simplicity.

Would the savings in fuel that it produces outweigh the extra costs of maintaining the more sophisticated electronics it employs?

I always felt simplicity was why so many of the engines used over the last 50 years are still the ones we use today.

27/09
13th May 2014, 01:00
Ixixly: I think the part that would concern a lot of operators, especially Bush Operators is the level of Electronics that is seems to employ to control it, I know a few Engineers that would bring up this point straight away. The more complex you make something the more there is that can break down and the more parts you need to keep instock to keep it flying or get it back in the air! One of the reasons so many people think of Diesel Engines as being a great introduction to their Aircraft would be because of their reputation as being reliable engines elsewhere, but I know from a few Diesel Mechanics that this is because of their simplicity.

Would the savings in fuel that it produces outweigh the extra costs of maintaining the more sophisticated electronics it employs?

I always felt simplicity was why so many of the engines used over the last 50 years are still the ones we use today.

Good points. I did wonder about the the issues created with the use of electronic fuel management. What are the real advantages of having a single lever? Keeping things simple sure helps with reliability.

Will this engine would run into the same problem as the Thielerts where a loss of electrical power means an engine failure. Remember the double engine failure in Germany of the DA42 when the gear was retracted after a jump start. I wouldn't want to fly a Thielert engine any further from a suitable landing area than the battery endurance.

Andy_RR
13th May 2014, 01:51
Apparently the iron block isn't heavier according to their blurb.


Of course it might be, but the comparison needs to be with existing aero engines, not a fictional aluminium block they might have used.

The cynic in me reckons if the weight was good news, they'd be shouting about it from the treetops. They're not, so I'm expecting the bad news to be concealed as long as possible.

Jabawocky
13th May 2014, 03:17
Quick peak at the graphs and a BSFC of 0.30 is pretty darn good, if it is for real.

Wally Mk2
13th May 2014, 03:40
'Ixixly' that's the exact reason why more so called modern engine types/designs aren't flourishing in the outback, too complex, nothing like simplicity when yr out there in the bush with just bush parts & bush Mech's about. Any savings on fuel would be instantly lost if one of these things stuck you up in tim-buck-too!
These sorts of power-plants have their uses for sure as DOD etc but doubt very much it will be in the front of an old crusty 206 anytime soon.

Wmk2

onetrack
13th May 2014, 04:05
Despite the smooth presentation and the big talk-up - I won't be holding my breath about the takeover of aviation power by this "radical" new engine.

1. Lots of "new" and "huge step forward" designs have been produced over the decades and only a couple have actually been placed into production - and there's been no major breakthrough as regards a widely-acclaimed and widely-used "new engine".

2. The specific "advances" mentioned in the technological features of this engine are not really advances at all. CG iron in blocks and steel pistons offers minimal advances in technological improvement.

3. A V8 engine design is not a radical advance in design, either.

I'll get excited when I see some truly radical advances in metals, technology and engine principles.

Sunfish
13th May 2014, 05:55
1. Electronics are more reliable than magnetos provided they are designed and constructed properly with sufficiently derated components. I would have thought Bosch has mastered this. As far as I know an integrated circuit doesnt wear out.

2. Quick google of CG iron shows that it may be just the "breakthrough technology" necessary for diesel aircraft engines.:

(a) five times better fatigue life than aluminiun.

(b) Solves engine design problems:

All V-engines share a common design weakness, as there is a lot of flexing in the V-area between the cylinders when it is under power. CGI strengthens this physical area considerably.

Audi is an early user of CGI material in its power production. All Audi 2.7L, 3.0 V6 and 4.0 V8 diesel engine blocks are now being made of CGI. The V8 main bearing caps are also cast in place, laser etched and then fractured for an absolutely perfect fit after bearing sizing.

The BMW Series 7 V8 engine was also cast in CGI. Hyundai, currently the number seven automobile company in the world, and rising, has V6 CGI blocks scheduled for full series production during 2006. Its World Rally Championship car (1997-99) also had a CGI engine block.

The new 2005 Jaguar 2.7L Ford/PSA V6 diesel is made of CGI. At 445 pounds fully assembled, it is lighter than a comparable aluminum diesel. Even the new James Bond will soon be driving a diesel powered Jaguar R-D6.

Other CGI Users [back to top]

Nearly all NASCAR teams are running CGI engine blocks, or blocks with CGI liners. These liners are usually plated with a hard-surface coating. It has been reported that some NASCAR teams are able to run a whole season without having to re-bore the blocks.

The Toyota Racing Development (TRD) campaign has the #12 Craftsman pick-up truck. This 5.8L V8 CGI engine block weighs 89 kg (195 pounds), has a 3 mm (0.118 inch) cylinder wall thickness and produces 650 hp (83.5 kW/liter). For comparison purposes, standard CGI diesel engines will soon be producing 66kW/liter.

General Motors’ Opel subsidiary has used CGI for the engine block of its 2.5-liter V6 DTM racing engine. Theoretically, a CGI engine block can be fabricated lighter than an aluminum block for equal power densities.

A recent 500cc Suzuki Grand Prix motorcycle engine had a crankcase fabricated from CGI. Nothing is put on these racing machines that would pose any kind of a weight penalty, and this is an extreme example showing the real potential of CGI applications.

P.S. Having just punted a 200 series turbo diesel Landcruiser to Darwin and back via the Alice and Perth, I have to advise that your tool kit these days apart from hoses, belts and filters, consists of a satelllite phone and a RACV service membership. Yoiu can't fix the engine of my Fifteen yeaqr old 80 series all mechanical turbo diesel landcruiser by the side of the road either if its injection system or valve train is stuffed.

VH-XXX
13th May 2014, 06:03
I had a Continental in my last aircraft with Fadec. I can't say it was the best thing since sliced bread having those electronics. If anything was wrong like a plug or something similar, a warning light comes on and you have no idea what's wrong until the LAME drops in. It was getting rather frustrating in the end.

If they can have a good reliable EMS included with it that accurately reports what is wrong, rather than just a warning, then great, it will be a good thing.

Brian Abraham
13th May 2014, 06:34
Ford Territory V6 diesel is also CGI. A common engine used by a number of manufacturers, Jaguar, Landrover, Peugeot. Citroen.

BEACH KING
13th May 2014, 07:14
Does it have a gearbox?..... or is the prop spun directly?
From the website picture, it looks to be directly driven. If so, a major drama with previous diesel aero engine design will be averted.

Wow A V8!! I bet it will sound great on take-off!
I still have lasting memories of the Queen Air with the excalibur conversion, and the Vickers Vimmy replica setting off from here.

And then there is the claimed 40% reduction in fuel burn! That will nearly compare with running LOP :E

Weheka
13th May 2014, 08:07
All the talk is of fuel savings, extended TBO, maintenance savings etc, nothing about performance comparisons? That thing would have to be fairly light I imagine and I didn't think it was ever going to get off the ground!

Maybe initial test flying means you just baby it along? Thats probably the reason.

Still, they must have some idea of performance against standard engines.

Oktas8
13th May 2014, 08:09
That will nearly compare with running LOP

All diesels run LOP... don't they? Comes from controlling power by fuel delivery, rather than by air throttling. Diesels therefore run at full throttle, all the time. Not full fuel flow of course. Very efficient way to run an engine, as all turbine drivers know. :ok:

I have several years' experience with running Diamond's product. Granted, we had LAMEs on site. But they couldn't repair anything electronic; all they could do was replace bits. It was the mechanical side of things that let down the Diamond product in the early years, not the electronics, which were very reliable.

Will this engine would run into the same problem as the Thielerts where a loss of electrical power means an engine failure. Remember the double engine failure in Germany of the DA42 when the gear was retracted after a jump start. I wouldn't want to fly a Thielert engine any further from a suitable landing area than the battery endurance.

27/09. The pilots of that aircraft took off in contravention of an explicit warning in the flight manual. They chose to operate the aircraft outside of a flight manual limitation. Diamond took a lot of heat over it, and perhaps in the long run that's for the best, as a permanent fix was found. But it wasn't their "fault".

Basically, an electric engine requires a digitally valid voltage (e.g. more than 5V, actual voltage I don't know) supply at all times to the FADEC. Now when you retract the undercarriage in a light aircraft, the hydraulic drive motor will briefly take 100% of both alternators' output. "Briefly", in this context, might mean as little as a tenth of a second. If you have chosen to take off with a known duff battery, the battery can't maintain system voltage over this short period. The FADEC will see a loss of voltage, and will sense that as a "shut down" signal. Game over, if you're at 100' after take-off.

The cure, for Diamond at least, was to state in the Limitations section that the engine (second engine for twins) had to be started on battery power. If you couldn't do that, the battery was not fit for flight. Of course, pilots ignored that warning, so now there are, in Diamonds at least, a couple of camcorder batteries (I kid you not!) hardwired to each ECU. To maintain voltage in the event of above-mentioned pilot's actions.

VH-XXX
13th May 2014, 08:16
My FADEC managed Continental had a second battery fitted and if you lost an alternator you were only going to last as long as the battery did for which the timeframe was clearly documented in the POH. Not much different really to the diesels. The FADEC battery was about a third of the physical size of a small car battery or perhaps about the same as an Odyssey 300, so not big.

27/09
13th May 2014, 09:28
Sunfish,

Electronics while being very reliable, do fail, they may not "wear out" as such but components fail, resistors can burn out electrolytic capacitors dry out, dry joints occur. Sadly more and more these days they are not field repairable, unlike the humble magneto.

Oktas8

Yes, I was aware that the DA42 had been operated outside the manufacturers recommended procedures. I used that incident to prove that lose of electrical power no matter how it might be caused can result in an engine failure. Unlike the old tech Lycoming or Continental engines.

Andy RR

You may well be right about the weight. They do talk about weight savings, however it appears they are talking about the weight gains due to the reduced fuel burn and the need to carry less fuel for a given mission.

Oktas8
13th May 2014, 09:50
27/09

Yes, you're right about a loss of power. I'm thinking that statistics are on the side of electrics though. Ignoring all the failure modes common to both engine types (cylinders, crankshafts, carburettor/fuel rail etc), which is more likely to fail: a pair of magnetos with associated drive shafts, wiring and plugs, or a pair of FADECs with associated electrical supply and wiring loom? I guess the aero-diesels are still too recent an invention to answer that question here. But long term, my money is on solid state electronics over mechanical parts, any day.

For the Diamond in particular to have a power failure these days, post-power-loss-incident, you'd have to lose the alternator(s), lose the main battery, then lose the dedicated FADEC backup battery. That's a lot of failures!

I would imagine that other manufacturers will probably learn from failures of the past, and have similar levels of redundancy.

But as I said, it's not the electrics that tend to fail on these things. It's the mechanical parts, including the cylinder head gasket (very high cylinder peak pressures). I watch this new CGI thing with interest!

cockney steve
13th May 2014, 10:13
Back in 1963, I had a BSA motorcycle, equipped with an Alternator, courtesy of Lucas, AKA "the Prince of Darkness" (Though their official slogan was "King of the Road")
The rotor contained permanent-magnets, therefore self-exciting, Rectification bt Selenium, superseded rapidly by Cilicon semiconductors. Aswitching arrangement Changed stator-coils from parallel to series configuration, according to switched load....an emergency position allowed kick-starting with a totally flat battery. as the battery voltage increased, it opposed the alty output and caused misfiring...a crude and effective system.....I must add,this was 6-volt. the later 12-Volt systems had a Zener Diode to dumpsurplusoutput.

A very simple, robust and cheap item to incorporate into an aircraft engineand the whole caboodle canbe internal! Battery-system could still be used , via blocking diodes...with a built-in alty and twin FADECs, such an engine should be far more reliable than the magneto-fed Lycosaurus breed.

The cost of electronic components, at these power-levels, is buttons. As a previous poster stated, components could be derated for longevity and Ireckon youcould probably double the power-handling capability for less than $5 AUD
per circuit-board.
For the cost and weight-penalty,there's no reason I can think of, why every engine should not have a spare, ready-mounted FADEC unit...in case of a failure "out bush" simply swap the plugs to the spare unit.......If a magneto goes sick, even an experienced fitter will struggle if, say,the points-spring has cracked or the condenser gone U/s.
Time to move into the 21st.Century!

nomorecatering
13th May 2014, 10:32
http://bmepinc.com/AEHS%20presentation%202012%2005%2008.pdf

Interesting presentation on aero diesels.

No Hoper
13th May 2014, 11:23
Continental Motors is pursuing the CI (diesel if you must) route.
TD300 is TCd in FAA land, and they have bought the Thielert engine rights.

Jabawocky
13th May 2014, 13:25
Unlike a Turbocharged avgas burner, you will not get flying behind one, and I do not imagine many folk would be keen either when they fly over high country like the west of the USA.

Anyone know why?

onetrack
13th May 2014, 14:34
Jabawocky - Yes, because there's a risk of a diesel engine with a set fuel injection ratio overheating at very high altitudes.
The turbocharger speeds up substantially (and therefore heats up more) with the thin air at high altitudes, and there's less exhaust back pressure because of the thin air.
If an aftercooler is fitted, the charge air reaches a higher temperature because of the reduced effectiveness of the aftercooler.

Diesel-powered ground equipment such as trucks and earthmovers are de-rated with adjustments to the fuel injection pumps, when operating at extremely high altitudes, such as in the Rockies or the Andes. This is done to prevent engine damage caused by overheating in the thin air.

If an automatic electronic fuel injection control was fitted to this aviation diesel V8, it would compensate for the thin air at high altitudes.
I seem to recall the Junkers Jumo ran to 41,000', but I'm not sure how the thin air problem was compensated for, in the Jumos.

OZBUSDRIVER
13th May 2014, 21:33
One track. Electronic injection for diesels compensates and enhances the cycle. Cannot say for the trucks I am driving but my common rail family hack is firing up to four times per power stroke. You are correct with the rack settings for traditional injector systems. Caterpillar placard their machines for work above a certain altitude...methinks 15000ft, if I remember correctly, bit of a giggle in this country...soooo, going by the monitoring circuits built in current common rail systems...I reckon the Bosch system will compensate for altitude.

yr right
13th May 2014, 22:18
Turbines with fadec run what we call PMA permanent magnetic alternator's they provide power to the FADEC system alone in emergency use when normal power is lost. And as such the engine will continue to run A classic example was the A380 all power lost to #1 engine but ran till they got enough foam into it to put the flame out.


The biggest problem with a diesel engine it has extremely bad hamomonics due to its power stoke is based on compression. A long time ago as I recall the French put one in a TB10 or 20. After the test flight and taxing back the tail fell of. This isn't the first time that has happen if they get it all wrong in the design stage has happened to normal type engines as well.
From what I recall you have to run a special prop with a rubber drive and increase the size of the engine mounts as well. Ever look a a late model car engine mounts now some are even computer controlled for better NVH especially when they drop out cylinder's for better fuel economy.


John dere made a rotary engine it was around 500hp from memory they could not get it to work Lcy brought it they ended up with a 500hp engine and a gear box of 2500hp rating to keep it all together then they gave up on the project.


The biggest problem is its extremely hard to go past what we have now as the norm that's because believe it or not they got it very close to perfect from the start. With modern machinery better alloys they made big increases in reliability but the basic confrig is still the same. Auto engines don't work in aviation its that simple, name one that dose. Only the VW engine works but that's not in commercial use.


For there investment I wish them well but it is going to be a hard road ahead for them. It dose look like a quality product I will give them that. Will it work only time will tell or will it end up like a lot that have gone before them lets see.


Cheers

yr right
13th May 2014, 22:23
Onetrack it is not px that drives the turbo it velocity that drives it.It only changes to px across the turbine . Velocity is the in the exhaust system is what is required that's why it has a convergent scoll onto the turbine.
Cheers

Andy_RR
14th May 2014, 00:39
yr right, pressure is velocity when it comes to gasses - heard of dynamic pressure?

At a molecular level, all pressure is is the velocity/kinetic energy of the particles

regarding diesels at altitude, you can drive your common-rail diesel-powered car/truck/what-have-you to more than 10000' AMSL in many parts of the world and not have it stop/break-down/overheat/fail to start. What's the difference if it's air in the tyres or air under the wings that's keeping the crankcase off the ground...?

onetrack
14th May 2014, 02:11
yr right - Well perhaps I should have made it clearer that the turbocharger on a diesel spins at much faster speeds in thin air, because the engine is running hotter.
The speed of a diesel engine turbocharger is directly governed by the EGT. The higher the temperature of the exhaust gases, the greater the turbine speed.
This is a self-compensating system for high altitude in one respect - that's the reason why many diesel drivers on the ground don't notice much power drop-off in the top of the Alps, the Rockies or the Andes.
However, the engine operating temperature of a diesel is the critical factor to watch at high altitudes.

yr right
14th May 2014, 02:11
Sorry px is not velocity at all.

Px increase velocity decreases temp increases

Or

Px decrease velocity increases temp decreases


All at subsonic flows

If what you say is true there would no need ford the convergent scroll.

Cheers

UnderneathTheRadar
14th May 2014, 02:11
From the website - their old website had videos of the engine running at altitude:

EPS has been testing the Proof-of-Concept Engine on its mobile test stand since November 2011. In a program known in the automotive world as “accelerated durability testing,” the team has run the engine through extremes that will never be experienced in the course of normal aircraft operations, including calibrations, low inertia props, cold tests, multiple rapid acceleration and deceleration cycles, and a battery of other insults to put the engine through its paces. In the summer of 2013, EPS drove the engine to the top of Mount Evans in Colorado to conduct high altitude performance tests at 10,000 and 15,000 MSL. The engine achieved full 350 horsepower operation at 15,000 feet density altitude and achieved 420 horsepower at low altitude. The engine’s liquid cooling system has been tested in extreme weather conditions, demonstrating starts in temperatures from – 25 degrees F to more than 100 degrees F. Based on hundreds of hours of testing as of April 2014, EPS can report significant technical breakthroughs, including

EPS | Ground Testing (http://eps.aero/the-eps-engine/testing/)

Andy_RR
14th May 2014, 02:31
Sorry px is not velocity at all.

Px increase velocity decreases temp increases

Or

Px decrease velocity increases temp decreases


All at subsonic flows

If what you say is true there would no need ford the convergent scroll.

Cheers

Your handle on thermodynamics and fluid dynamics seems a little limited, if you say this. BTW, the scroll is not the convergent/divergent part of a radial-flow turbine. The turbine itself is.

yr right
14th May 2014, 03:40
The scroll is a convergent duct. It goes from a large to small. There fore it must increase it's velocity and decrease it's px due gas laws. Once it passes over the turbine it changes as in any gas turbine Engine

Cheers

Andy_RR
14th May 2014, 05:39
The scroll is a convergent duct. It goes from a large to small.

The scroll appears to be convergent to the ill-informed, but it's just getting smaller because gas is escaping through the turbine wheel. The pressure/velocity is nominally constant around the scroll/volute. The pressure/velocity change happens as the gas passes through the turbine/compressor wheel. If it happens anywhere else it would represent lost mechanical work - i.e. inefficiency.

Oktas8
14th May 2014, 05:41
The turbocharged diesel cycle engine I used to fly, was certificated up to 20,000'.

So I guess the turbocharger was designed correctly to run in less dense air, without overheating.

I'm also going to guess that the manufacturer of this new V8 engine might have also designed it to run safely at altitude. Only a guess mind you... :}

But you'd want to be sure of mechanical reliability before you flew it over the Rockies, for sure. Or even our humble high country!

No Hoper
14th May 2014, 09:51
A Cirrus SR22 powered by an Engineered Propulsion Systems (EPS) Graflight V-8 Diesel engine made its first test flight May 2nd in Mojave, CA with Dick Rutan at the controls of the airplane.

A Successful Test Flight For EPS Engine | Aero-News Network (http://www.aero-news.net/index.cfm?do=main.textpost&id=cfaf27df-d659-4f72-a1f9-78b288f7a049)

Jabawocky
14th May 2014, 11:26
Anyone know what happens to a TC or TN avgas burner when an intake tube coupling leaks or as they do lets go? Yeah you get a NA engine. :D A mixture sweep sorts that but you can have power to divert safely.

What happens on these turbo diesels? ;)

waren9
14th May 2014, 14:58
not a fan then jabba?

Jabawocky
14th May 2014, 20:17
Yeah, I have driven some really amazing TD cars, but the laws of physics apply equally to all things (except the F22).

Wanna run JetA fine, buy a turbine. :ok:

27/09
14th May 2014, 22:42
Unlike a Turbocharged avgas burner, you will not get flying behind one, and I do not imagine many folk would be keen either when they fly over high country like the west of the USA.

Anyone know why?

Anything to do with how little power they produce when the turbo fails? :{

Andy_RR
14th May 2014, 23:58
Anyone know what happens to a TC or TN avgas burner when an intake tube coupling leaks or as they do lets go? Yeah you get a NA engine. :D A mixture sweep sorts that but you can have power to divert safely.

What happens on these turbo diesels? ;)

They belch black smoke distress signals and the fuel consumption goes into the ****ter, but generally they can keep running to a degree.

Oktas8
15th May 2014, 00:52
They belch black smoke distress signals and the fuel consumption goes into the ****ter, but generally they can keep running to a degree.

Yup. FADEC adjusts injectors for inlet pressure & temperature. To the maximum extent that it is programmed for.

If that happened over the mountains, I would ... increase power on t'other engine to compensate.

You wouldn't fly a single over the Rockies now would you Jaba? :p

Seriously though, once the bugs are ironed out of a new design (which will take several years to a decade) it is likely to be just as reliable as any other design. There is no evidence that a CI TC engine (to give it the strictly correct title) is intrinsically less reliable than an engine with spark plugs.

yr right
15th May 2014, 11:06
I can't see any difference really that all engines are compensates for altitude. Turbine or blown are all compensated can't see why this engine won't be any difference when it and if it get certified.
The test will be seen once it starts to fly. I'm sure there will be bugs it's going to be and if they can fix them.
Any one remember the hype over the thunder engine. It preformed better than the turbine engine in a 690 commander as I recall. Then sold some stc certified now gone and stc removed.

Time will tell.

Cheers

yr right
15th May 2014, 11:26
Andy
The inlet of a turbo scroll is convergent. This is before any gases are released across the turbine. Then the scroll continues to convergent path till the end this is to keep the velocity up across the whole of the disc to keep the forces equal across the centre bearing. Aircraft turbo centre bearings are made of aluminium any force that's not centralised will wear the bearing out extremely fast.

Px is distributed equally than as you say there would be no use for the scroll to continually decrease in size.

It dose not matter if it avagas engine Diesel engine or a gas turbine from an small Alison 250 to rb211 they all work on the small priceable velocity 1st the px change across the disc.

Now late model turbos in cars use variable vanes instead of a waste gate. The opening and closing of the vanes changes the velocity onto the disc.
In a gas turbine the same is used on the compressors to stop compressor stall on start up and low speed.

Cheers

Jabawocky
15th May 2014, 15:28
Andy,

They belch black smoke distress signals and the fuel consumption goes into the ****ter, but generally they can keep running to a degree.

Ahh but the mixture knob fixes that ;) A sweep will find the best of a bad day. :ok:


Yr Right, have a think about what it takes to run a compression ignition piston engine at altitude and what happens with a substantial loss of boost from a simple coupling, not a turbo failure even.

rutan around
15th May 2014, 19:56
Jabba
The penny has just dropped. Are you saying that at altitude not enough air means not enough compression to light the fire? Would sort itself out at lower altitudes but over the Seirra Nevada the silence would be frightening............

OZBUSDRIVER
15th May 2014, 23:15
I think you will find the four stroke CI engine will drop off slower than a SI engine with a failed turbo.

Andy_RR
16th May 2014, 02:39
I have heard that on the SMA it is possible for the diesel fire to go out on descent, which is why I believe they have a minimum descent power requirement.

On a liquid-cooled engine though, this is less of an issue because the cooling system can be thermostatically controlled to limit the rate of cool-down.

Having said that, since you can start and idle a modern diesel engine at the top of most mountains (FL100-120) I'd say the chance of losing ignition for a diesel engine because an inlet hose burst or fell off is pretty remote, especially under any reasonable power level that still remains. The beauty of a diesel engine though is that it doesn't rich misfire, hence the black smoke.

yr right
16th May 2014, 09:45
Well ive got to say ive never heard or seen an induction tube fail or come undone. That just comes done to simple maintenance procedures. Also never had a complete turbo failure ethier they give signs well before they die.
What may be interesting is if they able to put it in a px airframe and how they get a larger blower into the engine cowl.
and with one control it will be idiot prove lol
Cheers

OZBUSDRIVER
17th May 2014, 02:59
Interesting, a question for those who have flown behind either the SMA or the Centurion. With engine control, is the engine speed governed by power settings or pitch settings? I have always assumed that governor settings would be controlled by fuel input. In effect, if you go from cruise to climb, engine senses rev change and automatically inputs more fuel. Till WOT, pitch remains at cruise setting until revs start to drop then pitch changes to maintain revs....automatically.....autothrottle for lighties?

sms777
17th May 2014, 08:18
I am an avgas fan and could not be botherd using google....so my question is....Can you run your Toyota Land Cruiser on JetA or could you run your PT6 on automotive diesel?

onetrack
17th May 2014, 09:48
sms777:
I am an avgas fan and could not be botherd using google....so my question is....Can you run your Toyota Land Cruiser on JetA or could you run your PT6 on automotive diesel?In both cases, the answer is yes - but in both cases nearly all the manufacturers recommend against it.
It all comes back to the fact that each fuel is refined for a specific purpose, and refined to fuel specifications that apply to each type of fuel.

In the case of the Landcruiser - older diesel Landcruisers (with mechanical fuel injection) run quite happily on a mixture of kerosene and crankcase oil (not more than 5% oil).
However, newer models with electronic fuel injection have much tighter parameters for the fuel viscosity, and the ECU can sometimes reject the fuel once those parameters are exceeded. In other words, the engine will refuse to fire and a fault code will show.
I am not sure if JetA would be outside the viscosity parameters of regular road diesel in an electronically-injected Landcruiser. There is a difference in SG between the two fuels.

As for using diesel in a PT6 - yes, you can, but most manufacturers do not recommend it, because of the high possibility of the diesel fuel gelling or freezing.
Diesel fuel can be used in low level aviation operations, if the engine manufacturer approves.
JetA has lubricity improvers for improved aviation engine life, and other additives that allow it to still function satisfactorily as a fuel at the extremes of temperatures encountered in aviation at higher altitudes.
This question has been discussed before at length, on this forum - http://www.pprune.org/tech-log/444111-diesel-fuel.html

43Inches
17th May 2014, 11:00
The Su-25 could run on diesel for up to 4 hours. From what I understand it had a toolkit that allowed the pilot to make off field alterations to facilitate this to allow unscheduled front line landings (assuming on roads) to refuel from vehicle diesel and limp home. I don't think many commercial jets or turboprops would have this ability.

yr right
17th May 2014, 12:00
If you can burn it you can run it in a turbine. Some aircraft with pt6 alow you to run Avgas for a short time. This limits however the o/h periord but

I've seen a Alison 250 modified to run on coal dust. Not for aircraft use but
Cheers

nomorecatering
17th May 2014, 12:26
FADEC might be the temporary saviour of traditional engines, but as I see it, there will be a day where the oil companies simply refuse to manufacture a fuel that sells in miniscule volumes compared to Jet A and even automotive fuels. On top of that you need special distribution systems. I can see Avgas being priced out of the market in my life time.

In many countries you cannot get Avgas at any price. In that regard I think diesels are the only way forward. Aerodiesels are still in their infancy today, but I believe given enough time and money the problems will be resolved. They simply have to be.

43Inches
17th May 2014, 12:52
Many engines will run on anything combustible, the real issue is how long it will put up with it, what affect it will have on it, how practical is the fuel, such as power output, supply, weight etc... The GE LM2500 is a derivative of the CF-6, it's used in the ANZAC frigates, but it is modified for this use with marine fuels.

Oktas8
17th May 2014, 22:56
With engine control, is the engine speed governed by power settings or pitch settings? I have always assumed that governor settings would be controlled by fuel input. In effect, if you go from cruise to climb, engine senses rev change and automatically inputs more fuel.

As with any other piston engine, engine speed and propeller RPM are tied together. But I think you're asking more than that!

The FADEC controlled manifold pressure (via turbo wastegate), fuel flow (via injector timing) and propeller pitch (via oil valve). From memory there were about sixty inputs into the FADEC to tell it what was going on in & around the engine.

The power lever angle is resolved into an electrical signal, so the FADEC knows what power is being requested. Each power setting is associated with a particular RPM, so the propeller control valve would move to change blade angle to change RPM to match the target value. Entering a climb, reducing speed, would cause the FADEC to command a smaller blade angle to maintain RPM. That doesn't set power however. The FADEC could set power independently of RPM, by adjusting MAP and injector timing.

Fuel flow would be set by the FADEC according to a specific schedule - obviously depending on inlet manifold temperature & pressure, fuel type (diesel, JetA, JetA1 etc), and many other variables. The FADEC would adjust fuel flow and manifold pressure to maintain the commanded power setting at any given TAS, altitude and RPM.

It worked very much more smoothly than traditional engines with three levers.

I once had a propeller control valve malfunction in flight. RPM was cycling between about 1200 and 2300 RPM, with a period of 20 seconds or so. At first I thought it was a sputtering engine, but power output was rock steady and there was no yaw. Strange feeling! But it illustrates the relative independence of RPM and power output in these engines.

Obviously I would be more impressed by an engine that didn't fail at all. But, given that was early days of the Thielert engine, things have improved since. It is IMO the way of the future.

yr right
18th May 2014, 00:14
MMMM Fadec $$$$$$$$$$$$$$$$$$$$$$


Remember kiss
keep it simple stupid


Cheers

onetrack
18th May 2014, 00:59
yr right - I for one, also love the KISS principle. Unfortunately for us dinosaurs, substantial amounts of electronics that control a wide range of engine control inputs are here to stay.
If it wasn't for modern electronics, engines would still be relying on very imprecise engine fuelling setups, imprecise and less reliable ignition systems, and an inability to adjust a wide range of other important combustion controllers.

The main problems with electronics come with the "cheapest arrangement we can purchase" mentality, and the lack of knowledge of actual operating conditions by engine designers which results in poor positioning of electronics, and less-than-ideal-design wiring connectors and wiring harnesses.

Electronic components often have a huge profit margin in their selling price that is designed to recoup design and research costs.
If competition via aftermarket manufacturers is introduced, prices rapidly fall to realistic levels.
Unfortunately, aviation is still full of the "captive customer" or "captive market" production principle, that ensures high costs for owners.

yr right
18th May 2014, 01:28
Remember flat screens TVs that where upwards of 20k when it's first here now you can get them for $100. Now why is that. Mass production. Aviation isn't like that. It's a unequivocal low production where 500 aircraft is a great deal.
Now nothing in aviation is cheap. Nor dose it ever get cheaper. Litagation insurance is the main reason. Yet what is developed in aviation finds it's way to the greater public in other areas. Carbon fibre is a prime example.
I change a turbine disc just recently. At $2000 each turbine blade and 54 in a disc they use to be around $550 ea. that's over 100k just in blades.

Fadec fine but in GA I have to ask why. What happens when it stops. Now remember it breaks. Who has spares. Equipment to look after it. Who then pays for that. What happens if it stops in the middle of no where. I'm not against change but the cost is going to hurt. I've heard flying schools removing glass screens and going back to dials because they can't afford the cost of a break down at arond $25k a hit for a replacement. Won't hurt my pocket but may hurt yours.

27/09
18th May 2014, 02:15
onetrack

A good simple carby setup is more efficient than a good EFI set up in a modern car. Only problem is the carby set up will go out of tune quicker. Manufacturers plump for the less efficient EFI as it helps guarantee them a known state of tune and therefore known level of emmissions. Electronics are not universally better. Yr right makes some very good points as well.

Oktas8
18th May 2014, 05:42
Yr right - you're right. The cost is going to hurt, and it'll hurt more if an integrated circuit board dies in the middle of nowhere.

However, it's the way of the future. AFAIK, general aviation is now the only place where we buy 1950s technology with 2010s dollars. No disrespect intended to that technology of course - it's rugged and durable. But cars, boats, trucks, racing cars, all have moved to fuel injection, electronic ignition, hi-tech fuel economy, replace-it-don't-fix-it.

It's getting harder to buy avgas too, although that's a different argument.

No Hoper
18th May 2014, 06:27
FADEC is used quite successfully on light turbine helicopters, operating in very remote locations.
The EPS Vision 350 engine has a bosch general aviation technology control system so backup shouldn't be an issue.

CI is the way to the future, as long as initial costs can be lowered.

Derfred
18th May 2014, 09:05
A good simple carby setup is more efficient than a good EFI set up in a modern car.

Do you have a source for this?

yr right
18th May 2014, 10:35
A carby has a better mixture of the fuel to the air. That's why a 500ci prostock car can run at over 200 mph and mid 6 sec runs. This is not new information just everyone thinks cause it the latest it must be the greatest


cheers

nomorecatering
18th May 2014, 12:11
I have heard that about NASCAR engines from several engineers, but cant get my head around it. Obviously the NASCAR engines are built to perform well at a precise rpm and have a very narrow operating rpm range. Below 4000 rpm they buck like horses but come on song at 7500. The intakes, heads and valves are optimised for a specific rpm.

So why wouldn't fuel being squirted through an injector at 27,000 psi atomise even better than a simple pressure drop through the venturi of a carburettor?

BEACH KING
18th May 2014, 20:28
Plus the carby engine has the added advantage of being immune to carburettor icing ! Makes you wonder why they ever mucked about with this new dangled fuel injection stuff in the first place:p

Oracle1
18th May 2014, 20:54
A carby is very good at mixing fuel and air at the appropriate ratio when mass flow is constant, eg an aircraft engine at constant RPM. When you change the RPM constantly such as in a car in traffic the carby cant keep up and this is when fuel injection comes into its own.

I would be interested to see if petrol direct injection would improve combustion/atomisation/metering over a carby in an aircraft engine

Andy_RR
19th May 2014, 00:45
So why wouldn't fuel being squirted through an injector at 27,000 psi atomise even better than a simple pressure drop through the venturi of a carburettor?

It does, unless you're a luddite, in which case it doesn't

yr right is spouting so much ignorant ****e here, I'm surprised that everyone didn't pick up on 27/09's subtle satirical post...

OZBUSDRIVER
19th May 2014, 00:55
Yr right...now you're gilding the Lilly! You know full well the only reason that prostocker is running a carbie is because the rules tell them to!

I can tell you it used to take me half a morning and two runs for a plug chop to get my 250ci tripple SU powered XP hardtop to run into the 13s...with a little nitrous...any late model car will stay in tune months longer. Mine would change with the weather! My son's car will run tens any day of the week on a factory turbo and electronics with only a different wastegate and intercooler.
To quote a movie line..."His grandmother wouldn't be scared to ride in it" where my car ran a huge cam solid lifters and a 9inch that was more locked than it needed to...electronics are the go!

yr right
19th May 2014, 02:20
Bus driver having crewed on a pro stock car I know the rules. Yes that is true but then have a look at any other class and then look at what is achived with just 8 thoarts. Mid 6s at over 200 mph I think it's impressive then consider what initro cars where running with them times. A carby tune at the right end will produce more power than an injection in a N/A environment.

Cheers

OZBUSDRIVER
19th May 2014, 04:39
Yes, it is impressive what performance can be had out of a carbie that resembles four buckets tied together and over 500cubes of highly tuned induction system...enough to suck the air out of a 20ft container in a minute.

Okta, thanks for that. Pilots are so use to revs held static by the prop and having to watch manifold pressure where diesels fuel up the instant the load comes on...counterintuitive.

Derfred
25th May 2014, 09:36
So no one has a source for this.

Mechta
25th May 2014, 10:23
Quote:
A good simple carby setup is more efficient than a good EFI set up in a modern car.
Do you have a source for this? I went to a lecture by a Rover engineer some years ago who stated that they got more performance out of a 3500 (V8) SD1 car with Weber carbs than with the best EFI set up. The car buying public was clamouring for injected cars at the time though, so the Rover Vitesse was injected, simply because that was what would sell.

Going back to aero-diesel engines, mechanical injection is simple and reliable, however it is common rail (electronic) injection which gives the real gains in performance, economy and engine longevity, as the forces in the engine can be controlled so much better.

Piezo injectors give even better control and can allow more power to be extracted from an engine, but are, or at least were recently, prone to unreliability.

With electronics on a diesel aero engine, you have a choice between mounting the electronics on the engine or engine mount and have them shake around with the engine, or mount them in the airframe and run the risk of the wires fatiguing with the relative movement to the engine.

yr right
25th May 2014, 13:17
The reason for a carby preformance is it better atomises the fuel into the whole volume of intake air. It's down size is it harder to control than efi.
It the hymomics of the desiel that's the worry for me.

Sunfish
25th May 2014, 22:13
Bet you can't run this diesel Lean Of Peak (LOP) :E

yr right
25th May 2014, 22:36
No but im sure they will try cant run a turbine lop but they try that as. then they get a nice bill ti replace the blades etc and don't touch it again


cheers

Andy_RR
26th May 2014, 01:50
The reason for a carby preformance is it better atomises the fuel into the whole volume of intake air.


There is no basis in fact for this claim. The only advantage it might have is when the carb is positioned way upstream giving the fuel more time and surface area for vaporization. On F1 engines in the past, the injector was placed at the inlet bellmouth entry for this very reason. Of course it doesn't come without penalty, which is increased air-fuel ratio excursions during transient operation.

Most phased port injection systems are injecting on the back of a closed inlet valve - immediately after valve closing for sequential systems - so a large part of mixture preparation is by evaporation.


It the hymomics of the desiel that's the worry for me.

You worry about some strange and irrelevant stuff...

onetrack
26th May 2014, 01:51
yr right - By hymomics, I presume you mean harmonics. What adverse harmonics does a CI engine possess, that a SI doesn't?

yr right
26th May 2014, 02:25
Every driven a desiel and then a petrol car what's the difference. The rattle is the firing which give the proplem. They not a smooth engine on firing.

yr right
26th May 2014, 03:13
Which leads to something I just thought of. When we balance props we use accelerometers. These pick up the bad vibes in the engine. Not sure they will work on theses engines but

Aviater
26th May 2014, 05:07
The Austro Engine is certified to run on EITHER JetA1 (plus 2 dozen or so equivalents depending on your countries preference) alongside pump diesel. Add to that the economy you get from them, plus the longevity of the core engines and you've got the undeniable future for all light aircraft applications.

The V1 twin turbo diesel Diamond does 190 kts at 28000 feet burning a total of 36 litres per hour. or 18 litres per hour per side. (Coming from the mouth of Austro/Diamonds ferry pilot himself) Although the airframe is only certified to something like 18000 feet.

Austro are aiming for a 5000 hour TBO and are projecting an unlimited TBO into the future as their condition is constantly monitored via oil sampling at every service by the manufacturer.

They are also working on a number of larger applications in the 350 hp range which may already be in use by the US military in drone applications.

I've flown a couple of different diesel models on a number of occasions and I can say I was quite impressed with them. As for "ry igrht" comment re vibration I can confirm they are light years ahead of their opposite number in Lycoming. I can't comment on TCM as I've never flown a 4 cylinder 180-200 horse TCM.

In the Diamond twin (diesel), you can have the canopy open with both engines running and still have a conversation with your headsets off. They are that quiet and smooth.

Can't wait for more diesels like the V8 mentioned here are certified and STCable or fitted to production aircraft. Bring em on!

T28D
26th May 2014, 05:52
This would have to be the biggest piece of misinformation I have come across lately The rattle is the firing which give the proplem. They not a smooth engine on firing.


An Audi A8 V8 twin turbo diesel at idle is quitter than the petrol equivalent it uses Piezo Injectors that control the flame front with up to 8 fuel pulses and is just delightful to drive I owned one for a time, great car Euro 5 compliant without using Blue Goo.

No Hoper
26th May 2014, 07:11
T28D
SO what are the harmonics from if not the firing pulses?
The Vision 350 innovation allows the fitting of an aluminium propellor, previous diesels could only be fittted with composite blades. control the flame front Are you refering to flame lift off length, after initial autoignition? As you would know the flame in a CI engine propagates quite differently to that of an SI engine.

T28D
26th May 2014, 08:05
YUP As you would know the flame in a CI engine propagates but it is still a predictable flame front or she wont go !!!!!

No Hoper
26th May 2014, 08:22
That takes me back to diesel theory: Lift off, diffusion flame, cool flame soot, oxidisation etc etc. But it also makes that noise or rattle that Yr Right spoke of.
By the use of modern fuels, with better matching cetane number for swirl chambers and cylinder head design, CI engines can now be produced almost vibration free. Note almost, they all seem to have a frequency that resonates, a car can be geared to avoid that RPM

Andy_RR
26th May 2014, 08:59
the diesel noise is caused by the ignition delay of the fuel and depends on the amount of fuel injected before actual ignition. If you can get a lot in before it begins to burn, you'll get a rapid pressure rise as it all suddenly goes off together, which is the cause of the knocking/rattling sound.

pilot injections, rate-shaping, or whatever-you-want-to-call-it that the electronically controlled injectors do are all designed to limit the amount of fuel injected prior to ignition.

Having said that, not much of this has anything to do with torsional harmonics, hymomics or any other imagined figment that the propeller sees. It's the compression ratio that pretty much dictates the torque amplitude for a given load/power level

No Hoper
26th May 2014, 09:46
AndyRR It's the compression ratio that pretty much dictates the torque amplitude for a given load/power level Would you like to explain why?

Andy_RR
26th May 2014, 10:11
AndyRR Would you like to explain why?

Hard to explain without waving my hands in the air drawing imaginary diagrams, but...

...in simple terms, the net work done is the sum of the (positive) expansion work and the (negative) compression work. If you increase the compression work by increasing the compression ratio (negative torque pulse) you also increase the expansion work (positive torque pulse). The net work done is the same (more-or-less) but the difference between the two (torque pulses) is the amplitude. Hence higher CR >> higher torque amplitude.

cattletruck
26th May 2014, 10:12
Why not go back to radial diesels?

From the link Radial engine - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Radial_engine#Diesel_radials)

Packard designed and built a 9-cylinder 980 cubic inch displacement diesel radial aircraft engine, the 225 horsepower (168 kW) DR-980 (http://en.wikipedia.org/wiki/Packard_DR-980), in 1928. On 28 May 1931, a DR-980 powered Bellanca CH-300 (http://en.wikipedia.org/wiki/Bellanca_CH-300), with 481 gallons of fuel, piloted by Walter Edwin Lees (http://en.wikipedia.org/wiki/Walter_Edwin_Lees) and Frederick Brossy (http://en.wikipedia.org/wiki/Frederick_Brossy) set a record for staying aloft for 84 hours and 32 minutes without being refueled. This record stood for 55 years until broken by the Rutan Voyager (http://en.wikipedia.org/wiki/Rutan_Voyager).

A new Piper or Cessna would look awesome with a radial up front :ok:

yr right
26th May 2014, 10:14
Have you ever seen the engine mounts in a modern diesel car. They huge and not only that they also electronically controlled to smooth out the nvh. this is hard to over come in an aircraft when its fitted with a prop.
And as I recall now I may been wrong but don't they fire via compression, hence the rattle. Now the rattle is the problem as it sets up the harmonics though the whole of the airframe, as I said earlier a TB 10 or 20 was fitted with one and it blew the tail off it as it taxyed back after its first and only test fight, then you have the problem of a prop. Now as I understand they also fitted with a cushion rubber drive to take the pluses out.
In a modern car this is not so much as a problem as weight is not such a primary concern but in an aircraft it is.
Also as I said earlier im not sure you be able to do a prop balance on the airframe with one of these engines,


Cheers

No Hoper
26th May 2014, 10:36
the difference between the two (torque pulses) is the amplitude The vibration through the crankshaft would not vary as the pulses stay in balance, unless of course it is a single cylinder.

nomorecatering
26th May 2014, 11:49
I read recently that a diesels natural combustion properties mean it runs in constant detonation, hence the traditional clatter sound a diesel makes.

Modern diesel engines have eliminated this clatter by using a pilot injection that comes before the main injection pulse, as well as pulses of fuel injection after combustion has started.

Cummins 6.7 Liter QSB Diesel With and Without Pilot Injection - YouTube

yr right
26th May 2014, 11:58
I do no it's mandatory line replacement if you have to crack one open. $$$$$

yr right
26th May 2014, 22:07
I just watched that video and while the noise level has drop a hell of a lot you can still hear it with still means bad vibes

Andy_RR
27th May 2014, 00:02
The vibration through the crankshaft would not vary as the pulses stay in balance, unless of course it is a single cylinder.

That might be true on a multi-cylinder engine with an infinitely stiff crankshaft, however no-one's invented an infinitely stiff crankshaft yet. A radial engine is a close approximation though.

Andy_RR
27th May 2014, 00:05
...hence the rattle. Now the rattle is the problem as it sets up the harmonics though the whole of the airframe,

The diesel knock/rattle is in the 5-15kHz range and the engine mounts are not very well coupled at that frequency at all. It's like trying to remove the tail of your TB20 by repeatedly hitting the crankcase with a hammer...

onetrack
27th May 2014, 01:58
yr right - You're confusing sounds (hearing a diesel clatter) with vibration (torsional and longitudinal crankshaft whip).
Vibration will lead to airframe cracking, noise from the combustion process won't.

The fancy engine mounts in current diesel cars and light commercials are designed to prevent the diesel clatter noise from transferring to the chassis and body via amplification through the engine block, the chassis, and the body.

A CI engine has a longer duration power stroke than an SI engine. The power stroke from an SI engine is relatively short.
This accounts for the much higher torque production from a diesel engine.
The much higher torque level of an aircraft diesel is possibly more of a concern with regard to prop damage/life, than anything else.

The considerably higher compression ratio of a CI engine is what produces the larger rotational impulses as compared to a SI engine.
Most diesels are 16 to 18:1 compression ratio. The much lower compression ratios of SI engines produce much lower rotational impulses.
However, a misfiring SI engine (an exceptionally rare event in CI engines) would produce far greater rotational impulses, than a CI engine ever would.

yr right
27th May 2014, 02:20
I think you are missing the point. The rattle is where combustion starts. It's not a clean start to combustion as with a ignition engine. Hence the sound but that sound relates to the harmonics that are produced. When then are produced they travel through the airframe. It dose not matter what the frequency is if it what of a better term hurts the airframe. That's why the props are different and why the tail fell of. In a metal aframe they also produce cracking. They had an engine that was to be able to be placed into 182 etc but that never really took off ethier.

Cheers

cockney steve
28th May 2014, 08:47
They had an engine that was to be able to be placed into 182 etc but that never really took off ethier.
Diesel: for _ fuel economy,consistent performance, long mechanical life. virtually maintenance-free if fuel/oill filters and oil are serviced properly, fuel cheap and readily available worldwide.
against = usually heavier, noisier, the need for extensive research, refinement and certification, fuel could "wax" at altitude/cold-soak -because it will happily burn it, doesn't mean it should!

The huge cost of research, development and Certification, for the relatively small volumes of piston GA engines, means the economics are very tight.

Anyone remember the Porsche engine? Robin? (Just 2 I know of)
Thielert was beset with problems, despite having an assured sales-volume .
Jabiru hardly has a stellar reputation in the reliability -stakes.

On the other hand, Where Robin (and others) disappeared from the Microlight market,but Rotax continued development, thrived and has expanded. They now have a very real and potent challenge to the Lycosaurus market.

Lycoming and Continental, having recovered their development and tooling-costs decades ago, must be really hurting....the recent directive on aftermarket cylinders gives a hint of this Complacency, poor quality-control and protectionism is not the way to run a sucessful business!
Meeting the customers' needs and expectations, is, however, a fairly fundamental foundation..

Inevitably, due to the shrinking Avgas market, the future choice will be Diesel (OK, CI ) or Mogas continuing with it's limitations.
I forsee a decade or so of stuff with high maintenance and relatively short life (Thielert) until the engineering refinement gives a whole new era of low-maintenance,affordable GA Piston engines.

I have deliberately ignored Electric....that could change at a stroke with the invention of a light,cheap, high energy-density battery....already, solar cells are edging closer to being practical as an airframe surface-cover....but , although massive leaps forward have been made, there's a huge capability -gap to be bridged.

Just idle speculation from a bystander.

No Hoper
28th May 2014, 10:13
Steve, the Thielert Centuriian 2.0 lives on, part of the Continental Engine Group now.
Piper Introduces Diesel Archer | Flying Magazine (http://www.flyingmag.com/aircraft/pistons/piper-introduces-diesel-archer)

cockney steve
29th May 2014, 20:43
-@ No hoper , Yes, but the burden of all the early development costs was borne by those who lost their shirts, either directly swallowing a pill (taking an unpleasant loss) when Thielert folded, or buying a lemon powered by the troublesome, costly and maintenance-intensive early engines.
the new owner has , really, only the refinement costs to fund. That makes a huge difference to the profitability of the new product and also the legacy engines could well be a cash-cow, as the poor aircraft owner is well and truly caught by the gonads.....pay the ransom-price to keep the engines running, scrap the aircraft or , lastly, go through the process of converting to a different engine and getting certification.
Harmonic dampers are well-established in the automotive world, I don't see any issue with C.I engines for Aviation use...As has already been alluded-to, cold and thin-air are bigger things that could slow progress whilst their potential threat is eliminated.

yr right
29th May 2014, 23:09
The balancer wont take the impulse loads from being transmitted back into the airframe it is there to balance the engine some areo engines all ready have a external balancer and are also internally balanced with dampers inside the case. Harmonics are extremely damaging to an aircraft fuselage

OZBUSDRIVER
30th May 2014, 01:23
This is a design engineering issue. If this issue results in a placard having to be fitted to forbid or limit operation in a specific power range then the engineer needed to be sacked.

Why or what design issue would result in an engine, 0-360 A1A for instance, to be built with such limitations. Why would Thielert engineers allow their names to be put onto a design that fails so expensively?

Harmonics is not a dark art. Why complicate this issue? All we do is discourage any innovation within this industry. Lord knows, regulation has stifled light aircraft development into a multi decade old time warp.

yr right
30th May 2014, 02:08
Harmonics whilst not a black art it is a major issue that has to be over come at it's designed phase and the fact that aircraft engines are different to any othe engines that we all use on a day to day level. The fact that you swing a 5 foot prop of the end is we'll maybe an issue one would think ?

No Hoper
30th May 2014, 03:14
OZBUSDRIVER,
RR Alison 250 has an RPM forbidden to tarry range. So too PT6 engines that I know have the same. I think it would be inherent in the rotating components.

Oktas8
30th May 2014, 05:51
It's interesting reading about harmonics and dynamic balancing, and the causes of the "clatter" of diesel engines. All of it new to me!

However, I would like to inject a note of practicality. Torsional impulses, harmonics and so on do not limit the life of the Diamond product, singles or twins. It didn't with the unsuccessful Thielert engine, and (so I understand) it doesn't with the more successful Austro engines. There are no prohibited RPM ranges either, unlike (for example) the old Tobago TB10, with a horizontally opposed four cylinder SI engine.

Re Diamond, you could tell it was a CI engine in two ways. 1) Power almost independent of RPM, and 2) a horrible clatter on shutdown, as the propeller clutch shuddered its way to a stop. That's it. (Ok, and the lightweight propeller.)

Don't mean to put a dampener on the discussion - I'm learning lots - but let's not say "they can't do that", when clearly, they can.

yr right
30th May 2014, 07:46
Now one putting a damper on anything. But there is a lot of difference between a low HP engine to something they claim around 350 HP. I put more on later about problems P&W are having at the moment with turbine blades and harmonics

Ozgrade3
30th May 2014, 10:53
What is Compacted Graphite iron ?

COMPACTED GRAPHITE ENGINE BLOCKS Precision Engine (http://www.precisionenginetech.com/tech-explained/2009/07/02/compacted-graphite-engine-blocks/)

http://www.sintercast.com/file/documents/pdf/library-2/technical-publications-1/cgi-a-new-material-for-highly-stressed-cylinder-blocks-and-cylinder-heads-1.pdf

yr right
20th Jun 2014, 08:59
came across this


Pro Systems - Under The Scoop (http://www.pro-system.com/scoop92102.html)


carby vs injection


cheers

27/09
20th Jun 2014, 09:56
Good article YR Right

Andy_RR
20th Jun 2014, 12:00
came across this


Pro Systems - Under The Scoop (http://www.pro-system.com/scoop92102.html)


carby vs injection


cheers

I'll bet you did! :}

yr right
21st Jun 2014, 00:27
Andyrr what you not as clever as you thought you was. Hey the sky is blue. You need to wake up you not as smart as you like us to all think you are. You don't even know basic bgt. Drrrrrr

As I said you can make more power out of a carby. That is unless this guy is me and I've gone and made these carbys and set up a web site.

Instead of insults perhaps you should do some reading and exams and put your time into that instead of mindless posts.

Cheers

Oktas8
21st Jun 2014, 01:53
That is an informative website yr right.

There is one aspect of aero engine operation that it didn't discuss though: changing air density.

A carburettor engine designed for a wide variety of air densities needs either a mixture lever operated by an expert, or a very complex auto-lean mechanism. In practice these days, manufacturers rely on the first option!

A single-power-lever engine can be operated at the most appropriate f/a ratio at all times, and needs no special expertise outside the factory or overhaul shop. Granted you won't get the theoretical efficiency of a high-end expensive carburettor. But 90% efficiency with no hassles is pretty good for us "get from a to b no worries" types.

yr right
21st Jun 2014, 02:33
I totally agree with what you say about the efficiently of a carburettor. How ever the point was that you can make more HP/torque for a carby. For most application the high end is not required to the degree of what this carby dose. But it explains a whole lot and more the differences between the two systems. Then you can have a pressure injected carby which is an extremely complex bit of kit.
In drag racing now they measure grains of water in the air. It's gone from we'll let's try this to an extreme science to get the lasts tenth out of a machine.

There Arnt to my knowledge any Single lever piston engine aircraft that Arnt fadec controlled. There are however a lot of turbine engine aircraft that are.
The fuel basically in a turbine is ethier on or off. The pilot has no control over fuel other than a power lever. This is all because fuel is computed via air speed and placement of the power lever. In a piston engine aircraft this is extremly hard to do unless the use if electronics is used. Then that makes the system complex and takes away the simplicity of an engine. And the ability for the engine to run with out any electrical power.
It's all a balance in the end.

Aviation is similar to drag racing. How fast you won't to go is only held back by the amount of cash you won't to through at it.

I keep saying fuel is the cheapest thing you can place in an aircraft.

Cheers

Andy_RR
21st Jun 2014, 04:09
Let's be clear. Apart from the fact that yr right can't spot a little innuendo, that article is an opinion piece with no references and no date. It provides absolutely no factual evidence to support any claim. It is as much use as any other "found on the internet" information that's not subject to some scrutiny.

The only thing that carburetors have going for them is they are passive, mechanical devices. Whether they make more or less power on a dyno is pretty much irrelevant because engines are not useful on dynos. They need to be brought into the real world, where atmospheric pressure, temperature, fuel quality and density, wear and maintenance are all, for carburetors, uncompensated variables. So, for aircraft we give the pilot a big red knob to apply a crude correction factor to the whole system.

Unfortunately, so very few pilots know how to correctly use it.

In my opinion, a properly engineered FADEC would be far superior in almost every respect. It could compensate for most of the above mentioned factors and more. The automotive industry has adopted and developed the technology to the point where failure rates causing loss of function are at levels that even the big jets would be pleased with. Alas, with all the regulations that "keep the aircraft in the air" we won't be seeing it any time soon.

At least carburetors make more power on the dyno :hmm:

yr right
21st Jun 2014, 06:08
Let's be perfectly clear. In the automotive world where you can play and change to your hearts content were claims that are made that are incorrect are soon found out and products don't last. It was one article I came across that showed what really happens in the real world as I said very earl in this post. I have not and did not go looking for this but found that some people may find it interesting.
Not everything new is better. To be honest a fadec controlled engine is going to give you what. Sfa. Aircraft engines are as they are for a reason. There are no other production engines that will do what an aircraft engine will do. All fadec will do is take the leaning out of a pilots hands and may and it's a big may give a slightly better fuel use age. That's it.
Not really much of an advantage in the end. The reason why the auto motive industry was the tighten emission controls that have been imposed. A piston engine with spark ignition has a very narrow brand of schicometic envelope. And before you say efi gives better fuel economy yes but only slightly by being able to keep the engine in its envelope closer it the transmission that give the economy as we now head toward 9 speeds in passenger cars.

Cheers

yr right
21st Jun 2014, 06:10
Oh btw. Casa not so long back where pushing that all o/h aircraft engines had to be DYNO tested before release. The industry got together and where able to have it stopped before it was imposed on the industry.

Cheers

cockney steve
21st Jun 2014, 09:27
@ Yr. Right....I still remember when 6,000 mile plug -changes were the norm.
I had a V-8 Mercedes in, with electronic injection. The plugs were a textbook pale chocolate colour and the exhaust pipes very similar.....The owner was getting remarkable fuel-economy for such a big, heavy car.

I agree that for pure power-output, better results are had by carb induction...
but the usable energy extracted ,per gallon burnt, is what drives the real-life commercial and general transport world.
(there are some massively overpowered ,totally fuel-inefficient aircraft, of course,- think of the F1 round-the pylon racers like Paul Bonhomme....bet his only concern is the extra fuel's weight slowing him down)

You make a throwaway remark about CASA....Everything I've read on these forums, leads me to conclude they are an inept, self-serving beaurocracy which has lost sight of it's raison d' etre and hastotally inadequate supervision.
Surely you don't give any credence to this cunch of bunts ?

@Andy RR...thanks for the laugh! witty and apposite!

yr right
22nd Jun 2014, 23:00
Mmmm casa. We'll I worked against them they tried to have me removed from a court case as a hostile witness and I've worked with them. Unfortunately they are our regulator and with have to work within the parameters they set. But yes they made up now of ex military and airline staff that have no idea how the industry works and needs to be able to survive. Un like the UK we such a large country on a break down last week 2 1/2 hour flight at 160 average grind speed to get to the machine. Or a days driving there and then another back. It's sad to see what these clowns have done.
Aust lives of Sydney Melbourne and Brisbane and if you are any where else stiff ****.
How ever we just keep putting our heads in the sand and hope it will all go away. As can be seen with cvd but action has started. It only takes one stone to be pulled for the ache to collapse it getting to that stone. People have had enough of mindless crap.
To that point I believe that the Dalby case has been dropped by casa.


But back on track yes efi will maintain to a closer level the optimum mixture but it's only a small saving. Is it worth the development cost involved re invent the wheel. Personal I would think not. I guess time will tell. And nothing still beats the spark from a magneto.
Cheers

Andy_RR
23rd Jun 2014, 00:00
But back on track yes efi will maintain to a closer level the optimum mixture but it's only a small saving. Is it worth the development cost involved re invent the wheel. Personal I would think not. I guess time will tell. And nothing still beats the spark from a magneto.
Cheers

FADEC includes controlling ignition timing as well as fuel. That's necessary for getting the full effect, but it doesn't preclude using magnetos.

Good engine management will:

- improve fuel consumption for everyone by much more than "a small saving" - even those who are currently operating LOP
- almost eliminate starting issues at almost any temperature.
- make all of the possible power available whatever the density altitude.
- eliminate cylinder head temperature excursions that promote fatigue failure.
- reduce oil contamination from rich operation extending oil change intervals
- minimize or perhaps even eliminate plug fouling
- automate engine pre-flight testing - indeed monitor the engine condition 100% of the time
-allow operation on a wider range of fuel quality, including unleaded.
- automate and optimize turbocharger operation
- log engine run-time and fault conditions for better maintenance.
- a bunch of other stuff I haven't even imagined.

I can see why the established LAMEs wouldn't be interested though or actively promote such technology, because it represents a lot of new learning and a bunch of lost maintenance business opportunity.

But that's neither here nor there, because the real stumbling block is one of finance, development capital, litigation risk and the cost of regulatory approval. I was once pretty keen to use my experience in this area to develop something along these lines, but as it's mostly only GA-focused and GA is a shrinking market given the current regulatory environment world-wide, there is precious little interest in funding the development of such a product.

nomorecatering
17th Oct 2014, 05:00
It's been quiet on this thread for a while. Has anyone heared how the EPS engine is progressing through it's testing programme. It seemed to generate a lot of interest from punters at Oshkosh this year. Wonders if it is achieving it's targets.

Duck Pilot
17th Oct 2014, 20:36
Piper are quoting a new price of about $400K US for the Archer DX, with that price it might actually generate some buyers. Avgas certainly isn't the way ahead in my opinion. Once the bugs are ironed out the engine should be good.

yr right
17th Oct 2014, 20:52
But that will put Jaba out off bussiness. See what the future holds. Think Avgas will be around for a long time yet.

BEACH KING
17th Oct 2014, 21:26
But that will put Jaba out off bussiness (sic).

Pfft. It would take a CIA style hit man to put Jaba out of busy-nes.
Come to think of it... A bottle of Bundy rum does a pretty good job of it too.

I reckon the diesel V8 won't be generally available any time soon.

Eddie Dean
17th Oct 2014, 21:40
New "old" technology of the EPS engine is interesting, just had a look at their web site. It appears they are operating an aluminum propellor.
It had a lot of of interest at Oskosh.
I was talking to a bloke in Cairns that has a diesel in a 182?(I think), was ambivalent about the pros and cons.
Maybe worth considering when I replace the engine in the 206I can see why the established LAMEs wouldn't be interested though or actively promote such technology, because it represents a lot of new learning and a bunch of lost maintenance business opportunity.Hi Andy
Reading through the thread I noted your thoughts on maintenance of the engines. The maintenance people I know have a deep interest in new technology and gaining whatever qualifications required, so I feel they would view it as more income not less.

yr right
17th Oct 2014, 21:53
People are can't afford to do an o/h now how are they going to be able to afford an engine replacement. Remember the the thunder v8. Where is it now. Dead and buried. The reason we have the engingunes we have now is because they got it right in the first place. With modern electronics I'm sorry that's not going to be the answer. Will you pay more for your service to maybe have less done. Your brains are clicking now. Wtf is he in about. Who is going to pay for the computer box to fix it when you have one aircraft to look after. I'm not against improvements but they come at a hugue cost to all them that are involved. Then you have problems of the machine saying something's wrong. Then you spend a day looking for the proplem to find it's not fitted and it's a soft where proplem. Who gets that cost. I'll tell you we were it. So unless your prepared to spend more and I really can't see GA doing that can you.

Eddie Dean
17th Oct 2014, 22:20
Hi Yr Rite
You have probably nailed the problem with marketing the engine as a retrofit. Won't be viable.

Andy_RR
18th Oct 2014, 07:26
Well, you have all the fancy glass cockpits, probably running linux-derivative OS's behind the jazzy graphics. The easiest and best solution would be to have the diagnositics functions, read-outs, service notes, service history etc. on-line and available to everyone, pilot, LAME et al. No need to plug anything in at all!

Just because it is new, doesn't mean it has to cost more money to service, if it's designed right...

yr right
18th Oct 2014, 08:15
News flash. The aircraft will be able to give you the code with out any computer attached.

No ****e.

Aviation Andy is a leader and not a flower. We been able tondo this since the 80s. A little known aviation company you may have heard of is called airbus. It's aircraft where always sick. They always where calling the boss to say I'm sick and can't work today. Then the dr was called only to find nothin wrong with you off you go.

Like the problem we had. I'm sick. Go though everything only to find out that it wasn't even fitted to the aircraft. But you have to go though everything before you can say nothing wrong with you.


Now the difference between automotive world and aviation we have to have everything certified before we can use it. Those cost have to be then flowed on. Now when you consider that ford in the first 18 months of sale sold over one million units. I doubt if we even produced that figure in the whole of aviation since the first flight was done.

Cost never go down in aviation manly due to litigation cost but also nothing stays the same for long. May look the same but new materials are I then uses.

Aviation never sleeps but desiel engines will produce there own problems

Andy_RR
18th Oct 2014, 08:37
Everything's certified in the automotive world too, you know. Red tape abounds there too!

...and they have diagnostics systems you LAME's can't even imagine

...and they sell millions of units a year.

Now, who's leading and who's following...?

Eddie Dean
18th Oct 2014, 08:43
Just because it is new, doesn't mean it has to cost more money to service, if it's designed right... Agreed Andy RR
I would assume that the FADEC on the Graflight engine would have the same interrogation function as modern vehicle ECUs, so may not require any specialest equipment, just a bridge to short out the appropriate terminals and a flashing light.

yr right
18th Oct 2014, 09:00
Yep you win.
Lots of muti engine cars with complex fly by wire controlling 5000 to 8000 psi hydraulic systems and cabin px systems with carbon composites and carbon brakes with full anti lock temp sensing with wheel px relaying systems and muti avionics with gps Atsb hf and VHF and telemetry via satellite in real time with full fadec engine control. Nah we use none off that.

yr right
18th Oct 2014, 09:14
Oh and what about roller lifters and viable cams fuel cells lithium battery's carbon fibre composites aluminium panels etc etc. just about anything you can bring up has been tried or used in aviation in the first instance.

yr right
18th Oct 2014, 09:18
As the saying goes every thing is new again.

27/09
18th Oct 2014, 09:31
Everything's certified in the automotive world too, you know. Red tape abounds there too!

...and they have diagnostics systems you LAME's can't even imagine

...and they sell millions of units a year.

How many million aircraft are sold each year, there in lies the problem with amortising design and certification costs.

The OEM market may survive but I don't see the retro fit market taking off, it'll cost more than most aircraft are worth.

The only reason we had electronic GA EFIS was the development of stability systems in motor cars which paved the way for the "gyro" systems in the EFIS screens to be built at economic prices. But for the systems to get market share they still have to be priced competitively with existing gear and provide extra functionality, which of course they do in spades. Just to get some idea of the cost of certification compare the price of EFIS units for the home built market to the certified GA aircraft market.

Unfortunately a diesel engine doesn't provide a major step ahead for most owners to bother with the cost. Plus unlike an EFIS system which will pretty much fit straight into the existing panel for most aircraft, with a diesel engine there's the changes to the engine mount and probably fuel system and quite likely new cowls and prop etc. Not insignificant items. All to do what?

yr right
18th Oct 2014, 11:37
Desiel retro fit has already been tried and failed due to cost. Aero enterprises at lismore tried it 10 years gone back.

yr right
18th Oct 2014, 12:08
I have to dis agree on cars given us efis in GA. Efis in GA has been around a lot longer than the use in cars. I would think there are more aircraft manufactures using glass screens than cars manufactures. If you really need to thank anyone it would be the computer industry and also the gaming industry. They the ones that really have made a Difference to screens and to making them smaller lighter and reliable. Rate gyros in the hand controller for motion detections.
But still once again the progression came for aviation down to the motor industry and not the other way.

But once again the cost and repair cost can cripple you when they fail. And they do fail.

Jabawocky
19th Oct 2014, 01:23
But that will put Jaba out off bussiness. See what the future holds. Think Avgas will be around for a long time yet.

http://www.beechtalk.com/forums/images/smilies/rofl02.gif

It will?

I think all of GA can disappear along with all the LAME's, the airlines get robots to fix their jets……..and it will have zero affect on my business. When all food production, water, sewage, power generation, road building, construction materials, mining, brewing, hospitals, <keep adding every industry sector you can dream of> and all the other industries in between disappear, then I am in trouble.

Just a quick look at Diesel Aviation engines and fuels, the calorific values, mass etc. For the comparison lets look at the pick of the Diesels so far, the SMA 230HP in the C182, and a typical GA engine the 260HP IO540.

Remember the Diesel burns Jet A, with a SG of about 0.81 and 128K BTU's / gallon. Avgas is about 0.71 and 114K BTU's / gallon. Lets for arguments sake assume tank volume is not an issue, because you can get more kg of Jet n the same tank and MTOW is, the Avgas KG=160.56K BTU's. The Jet A is 158.0K BTU. The Avgas has about 1.6% more per kg.

BSFC, the key diesel strength is impressive and the SMA quoted figures are 0.36 and compared to say a typical IO540 at 0.39-0.395 or even a TNIO550 at 0.385 you can say it is roughly 10% better. If you look at the lower compression engines such as many TC's then the BSFC gap is even greater.

I have not compared the SMA to any lower compression TC engines because while you could argue the SMA is turbocharged, and it is….it is not comparing real world apples with apples as it has to be TC just to match the N/A 540/550 as is the nature of the beast. In fact that is also its achilles heel.

Next is the weight of the power plant 455 lbs to 410 lbs, naturally the SMA is heavier, and this will affect the fuel payload assuming all other things are equal, as to what the net affect is will depend on the mission.

One advantage is the SMA will hold its HP up to 10,000' and that has a TAS benefit as the IO540 will be around 60-65% of its power at those kind of heights. The squared law comes into affect of course so it is not going to be quantum leaps faster. The C182 is about 11% faster for the same fuel flow, so there is a lot to like about it.

The downside is the cost, however the fuel is roughly 11-13% at the Shell pumps around Oz more for Avgas so that can have an impact when there is a 10% less burn. Makes the MPG about 24% more in dollar terms.

There is a lot to like, but this is a niche machine for one, and it is not going to be across the fleet any time soon. The STC process alone to convert the fleet is prohibitive for a start. Let alone all you folk who want EO's even with the STC.

The other down side is many GA pilots have had many intake leaks……and most never know about it (but that is another story) and this is my main concern. Look at the lovely picture here http://www.smaengines.com/IMG/pdf/Fiche_SMA_SR_305_Engine_BAT.pdf and ask your self what happens with those pretty blue couplings when all is not 100% right. On your typical IO540 or even a TC/TN engine you have a manageable albeit non conforming engine. The SMA you have silence. :uhoh:

Pick ya poison!



Disclaimer: Numbers quoted are approximates and all is "back of beer coaster" calculation and analysis. In true PPRUNE tradition ;-)

Hempy
19th Oct 2014, 03:58
Jaba :ok:

yr rihgt, what are your expert opinions about runnng diesels LOP?

:}

yr right
19th Oct 2014, 04:02
Humpty Dumpty the k()&.

yr right
19th Oct 2014, 04:12
Most folk don't know they have an induction leak. Where is your data on that. That's another I pull that out of the blue sky. What a crock. Induction leak is the quickest thing you will know about may take some time to find where it is. So Jaba are you a master of every thing I take it. Ga will always be around. Maybe be not for private but there still a lot of work out there besides private work.

Jabawocky
19th Oct 2014, 04:12
Hempy….myself being a conservative kind of guy would opt for LOP, but I can imagine some out there telling us ROP is the only way to go :}:}:}


You are funny whoever you are :ok:

yr right
19th Oct 2014, 04:16
Jaba

For the record exactly what aviation qualifications do you have.

Cheers

yr right
19th Oct 2014, 04:37
Jaba
Since jan 2014 how many days have you spent in maintenance hangar preforming maintenance

Andy_RR
19th Oct 2014, 04:54
yr right, your last two posts are what's known as argumentum ad hominem. Grasping at straws, methinks...

Andy_RR
19th Oct 2014, 04:59
How many million aircraft are sold each year, there in lies the problem with amortising design and certification costs.


The real problem is that aviation in general and general aviation in particular wants to keep itself mysterious and elite. If it were democratised, like the auto industry, it would be able to generate the sales and use volumes that would bring prices down. Unfortunately, between the regulators and the epaulette brigade, there is some resistance to doing this. Sad really, because for point-to-point transport it is pretty efficient on a passenger-mile and infrastructure cost basis.

yr right
19th Oct 2014, 05:11
I don't have to grasp at any straws at all. The point is I'm making is that people like to have a dig yet they don't have the qualifications to have it. Like he has told me I've and we all been issuing M/R we on yet he has never issues one. He also dosnt understand a burnt valve and how it happens.

No one besides the regulator dosent won't GA. The damage is the legal profession like it or not. When tcm can make a whole new engine from paper with the cost of their insurance each year there lies the main proplem.

yr right
19th Oct 2014, 05:25
Oh and then all what I've been taught learnt and found out myself is all wrong because Jaba and his clones say so. To be told I was dangerous was quite liable lucky I not pressured I. That way to have taken action for that coment. But what I've been told is true after the acciedent in Melbroune this week some things may be up for change as they going to be very closely looked at.

Jabawocky
19th Oct 2014, 06:11
I don't have to grasp at any straws at all.

Might not have to……but you do it an awful lot. :=


Most folk don't know they have an induction leak. Where is your data on that. For once that is not a DATA POINT i have collected but it is anecdotal and accurateThat's another I pull that out of the blue sky. What a crock. Induction leak is the quickest thing you will know about may take some time to find where it is. No it is not, massive leaks yes, but I really do wonder how many engines you really have first hand diagnosis experience on when you make comments like that. Most leaks (by number) are not the massive ones that are dead easy to feel and easy to find. However, the majority are for the non LOP and data analysis nerds insidious and sneak up slowly over time, and without an EMS and knowing what it is showing you, will go undetected for ages, and even years, even after an annual inspection. There is one in my hangar right now, recently back from one of the better maintenance shops around. They simply could not explain the pilots question other than its a carby distribution thing.


Jaba

For the record exactly what aviation qualifications do you have.

None, I am a 7 year old kid in primary school…..who just gets lucky on his engine theory stuff :ok: But just like asking who knows more about the design of a B747, the engineers who designed it or the lady screwing the Hyloc's in the aft section of the fuse? And yes I know that answer to that one in more detail than you can imagine ;)

The point is I'm making is that people like to have a dig yet they don't have the qualifications to have it.
Do I have a LAME licence like you have….no, but that does not mean you are qualified to comment on 99% of the stuff you do. Some regardless of your "qualifications", you are qualified to comment on however. There is a subtle difference.

I think if we divided Andy RR's qualifications by mine numerically we would still have a numbers exceeding yours…..but really in the end that is just a pi$$ing contest and means little. So quit while you are not so far behind on that, and we might drop it too. :cool:

But what I've been told is true after the acciedent in Melbroune this week some things may be up for change as they going to be very closely looked at.

OK, what do you have to say on that? It better be good, and accurate.

Jabawocky
19th Oct 2014, 06:17
So back to the diesels…..


Yr Right, Hempy asked you a straight direct question. Sorry to distract you.

27/09
19th Oct 2014, 06:32
If it were democratised, like the auto industry, it would be able to generate the sales and use volumes that would bring prices down.I like your optimism but even if things were changed to the way you suggest I doubt they'd get the economies of scale.

yr right
19th Oct 2014, 06:32
Oh rang

You finish assembling your air fix kit yet ?

yr right
19th Oct 2014, 06:34
So Jaba sorry but what aviation qualifications do you have

yr right
19th Oct 2014, 06:38
We'll I can say a whole lot more dyicnoics than you Jaba. I've had to remove 5 engines in the last 3 months for various reasons. And I can tell you an induction leak really is not common and when you do have one it's quite simple to know what it is.

Hempy
19th Oct 2014, 07:46
http://i87.photobucket.com/albums/k144/h3mpy/90284439-6DAB-4FB8-A50E-C5CB37A2E965.png_zpshhawc4ao.jpeg

Jabawocky
19th Oct 2014, 07:57
And I can tell you an induction leak really is not common

Really? Not the ones you don't know about!! Most pilots and LAME's never know until such time it is actually so damned obvious that ….
it's quite simple to know what it is.
19th Oct 2014 16:34

:ugh:

But let me say this, regardless of what you think you know about intake leaks (the easy ones) the Turbo diesel ones will be REALLY easy to detect :}


So, please tell us all how and what tools you would use to find an intake leak (that is very easy for me to detect), that offers no rough running and no visible stains or anything visible to the naked eye. And it still ran fine LOP, which normally is one give away, and started and ran at idle quite happily too.

I am genuinely keen to learn (no doubt others also), as I am prepared to admit I do not claim to know everything and there is always a chance I could learn from you on this topic apparently.

yr right
19th Oct 2014, 08:15
We'll Jaba you proclaim to be the super hero here you quite often told me how my training is inadequate and my text books are all wrong.

You still not told us all what aviation qualifications you have or how many days this year you spent in a maintenance shop.

rutan around
19th Oct 2014, 09:10
You still not told us all what aviation qualifications you have or how many days this year you spent in a maintenance shop.

Does it really matter? 71 years ago a man trained as a biologist and paleontologist who probably never laid a spanner on an aircraft did more for rational maintence and data based military operations than all the LAMES and aviation rulemakers put together.

He improved aircraft availability by 60%, surprise attacks on submarines by 30% and submarine kill rates by 700%. God knows how much money he saved the military from wasting.

His name was Conrad Waddington. Look up his story. It's very enlightening.

I have a dream............ LAMEs and CASA will come together and produce data based maintence.

Currently most LAMEs know half the stuff they do is BS but don't change anything because by law they can't and CASA won't change anything because ????????? (Someone help out here)

yr right
19th Oct 2014, 09:39
Yes a lot of stuff we have to do is BS. I've stated that before. Like I have to put down IAW c421mm 32-10-05. That's bs. Not going to help anything. There is a lot of bs but then there is a lot that isn't.

Dose it matter. Yes it dose. I don't tell a heart surgeon how to do his job. But people think they can do ours. I loved to get some off you and put you in the hot seat when the px on. Have 4 different aircraft in the one day with different problems.
It's easy to be an expert at one subject. How ever we don't just do one thing. We don't sit down and have a chance to look at super dooper gauge with all the bells and whistles in fact 99.9% of aircraft don't even have them.

To have someone that thinks he would know more about trouble shooting an aircraft engine problem that has no aviation qualifications just shows the contempt he has. No wonder there are no lames. But hey you all can do it it's easy.

Jabawocky
19th Oct 2014, 11:11
Steve, answer half the straight questions I have asked you in the last year, and then start asking me about who is qualified for what.

I have already told you…..primary school and not yet finished, but that does not change the facts of the discussions.

You have argued black was white with highly qualified folk on here (you are just naive as to who they are and how well qualified they are) so it really matters not whether I passed or failed finger painting or not. Whether I studied engineering or not, whether I am a qualified pilot or not, or what ratings I may or may not hold.

You have argued wrongly on so many topics with far better qualified people than me on so many topics….I must say that my education and industry experience and any university papers are actually irrelevant and worthless.

I actually want to meet you, because up until now the smartest guy I have ever known is George W Braly and I can assure you I know rocket scientists and industry leading engineers. So you will no doubt trump them all.

So please, answer the god damned questions and quit the BS. My questions or Hempys, Creamies, Rutan's or anyone else's are worthy of the same level of respect regardless of our maintenance licences or anything else.


We'll Jaba you proclaim to be the super hero here you quite often told me how my training is inadequate and my text books are all wrong. That is a complete lie, I have no cape and no intention of getting one, but I do claim to be educating against the misinformation and the incorrect teaching not only in your text books but mine.

And yes I do have the data o prove it. So do many here.

Go back a page or two and answer some intelligent questions, otherwise we might start asking you about your qualifications (not that they matter) it is the quality of the response that matters.

yr right
19th Oct 2014, 21:47
Jaba

You should have been a politician.

I don't claim to be a dr a rocket player a cane toad hunter. What I am is an lame that is not a sheep that has a mind and qualifications that allow me to pre form maintenance on aircraft in aust and o/s. I work day in day out and that's all I do. I don't have a visit today and a chat.
I don't have a uni degree nor do I need one. You may have some theory but that dosnt make you an engineer. If you think it's so easy why don't you and why have you not become an lame

junior.VH-LFA
19th Oct 2014, 22:28
yr right.

In all the posts I've seen you make, you've spent 99% of your time telling others how bad they are, how under qualified they are, or how arrogant they are. I'm starting to ponder the same questions about you.

Whether its slagging off RAAFies in the VH-MDX thread, in any maintenance related threads, aircraft ownership threads (BK LAME Argument) or even in this one, there always seems to be one constant... and I think a lot of people are growing tired of it.

yr right
19th Oct 2014, 22:35
Jun
I'm pleased for you.

yr right
19th Oct 2014, 22:40
I call it as I see it. If you don't like it then please feel free to not read what I post. If they feel free to have a dig at myself I feel free to have a dig back. And if they not qualified then let them tell it is that way.

Jabawocky
19th Oct 2014, 23:49
You may have some theory but that dosnt make you an engineer.


…….no……but I are won :)

And I run a multidisciplinary engineering company. Is that enough for you. See it makes no difference what my qualifications are.

Besides you have argued with far better qualified folk than me, so who cares.


Now could you please get back to answering the questions asked….PLEASE!!!!

If I had three days spare I would go back and copy out all the questions asked of you that you have ignored. It would make a very long list.

If you are going to participate in an intellectual discussion at least try, and stop spraying BS about what you are qualified for and what others may not be, a usually one finds out later that it matters not but rather the quality of the discussion.




Jaba

You should have been a politician.
I will take that as an insult….thanks! :} But geez I at least answer questions and ask questions on a topic that I can be a contributor to.

You should be able contribute too given your vast experience and extensive high level qualifications, yet you fail to answer the questions and dodge duck weave and deflect.

Which set of attributes sound more like a politician? Old Sir Joh had nothin on you! :ok:




Hempy

Join Date: Oct 2002
Location: ɐıןɐɹʇsn∀
Posts: 1,300
Jaba

yr rihgt, what are your expert opinions about runnng diesels LOP?


Hempy is online now Report Post


Start with that one, or how about just some rational discussion on my thoughts of the SMA Vs an old gas burner http://www.pprune.org/pacific-general-aviation-questions/539687-diesel-v8-flys-7.html#post8703969

ForkTailedDrKiller
20th Oct 2014, 00:24
Good data don't need no uni degree! :E

Hempy
20th Oct 2014, 00:52
Don't hold your breath Jaba, the only answers you'll get are some ad hominims and bluster. This is generally how people with no idea tend to try and keep the illusion of 'knowledge' going when their bluff has been called. I wouldn't give him a lawnmower to service tbh, I'd probably end up with a massive bill for replacement clys

Andy_RR
20th Oct 2014, 02:24
I don't have a uni degree nor do I need one. You may have some theory but that dosnt make you an engineer. If you think it's so easy why don't you and why have you not become an lame

The real question that needs to be asked is, given LAMEs are so badly done by, why do you persist? If doctors and chemical engineers can turn their hands to building airworthy aeroplanes, can't disillusioned and undervalued LAMEs like yourself, yr right, use their talents in some other field...?

yr right
20th Oct 2014, 07:36
Oh Andy I can. And when you say build aircraft what you really mean is assemble them as a kit. Not many people actually build an aircraft.

And yes I can go and do other things however I choose not to. And your self that dosnt know basic gas and actually dose not know how a turbo works.

I'm actually good at my job btw

Oracle1
20th Oct 2014, 08:25
Haven't posted in many months and I return to find yr wrong spouting the same drivel. No wonder this industry is f&*ked when you look at the idiots who populate it. The RV8 is coming together and rest assured it wont be powered by a diesel. Bye bye certified aircraft forever cant wait to check out! Yr Wrong you wouldn't have the skill or patience to build an aircraft from scratch anyway, kits have revolutionised home building so much so that people are refusing to cop the bull**** of certified aircraft and are building there own, its cheaper in the long run.

Oracle1
20th Oct 2014, 08:32
The real question that needs to be asked is, given LAMEs are so badly done by, why do you persist? If doctors and chemical engineers can turn their hands to building airworthy aeroplanes, can't disillusioned and undervalued LAMEs like yourself, yr right, use their talents in some other field...?


Andy most LAMES have wised up and are leaving, hence the ever increasing average age, working furiously on getting out myself.

yr right
20th Oct 2014, 08:34
The skill not to make an aircraft from paper hey. Who says I haven't already. Who says I haven't been involved with one now. Good for you. I can assure you I have the skills to spare. But go a head assemble your kit but don't say you built it because you haven't.

Oracle1
20th Oct 2014, 08:47
Show us the aircraft you have built from scratch?

Andy_RR
20th Oct 2014, 10:50
You must have a real bad self-esteem problem, yr right. Anyone who denigrates the builders of kit aircraft either hasn't built one to know the effort it takes, or suffers from chronic sour grapes.

Oh, and in between rivets on my RV-8, I machined a radial flow compressor impeller for a friend's gas turbine project. Fortunately I didn't have to have CASA to tell me I was competent enough to do it. I just taught myself how it's done and went ahead and did it! Not that I'd call myself a machinist by any stretch.

Perspective
20th Oct 2014, 11:03
Why I feel compelled to chirp in I'll never know.
Yr.right (here goes) for what its worth,
You may be a very good engineer, but no matter how accomplished a
Technician you are, unless you become more articulate, and less
Defensive, no one is going to take you seriously.
Why do I care?
Because it is the completely unrelated responses and reactions found in threads
Such as this, that pilots and flying enthusiests remember above all else.

Trust me, I have seen first hand how vocal individuals, through emotive
And inflammetory responses have helped pursuade the demise of a facility and the
Loss of hundreds of jobs, along with the perception that we were all obstructionists.

What these few individuals were saying may have been right, but by putting it across
In a confrontational way won few friends.
I get the feeling there is a growing perception lame's are one of the problems in GA.
And this does nothing to kurb that perception.

Im guessing neither you, or i have worked on diesels in aircraft, I look at this as I might actually Learn something. I miss the training i used to get.
None of us know everything. If you have some useful information regarding the title of the thread, I'd love to hear it. Have your own opinion about it, great, but tell me why,
One thing I have seen is the inference that a solid state Fadec control might be good, but i have changed a few ignition control modules and voltage Regs that have failed internally, so, unless its made by Honda, forget it! (They were ducati regs!)

Eddie Dean
20th Oct 2014, 11:40
The FADEC modules are very robust and have a very low failure rate, to my knowledge that is,

So I wouldn't imagine that the control would cause maintenance issues, a laptop may be needed to download engine data at periodic inspections, not unlike the Bell 407 FADEC.

The engine I have interest in is the Graflight 350 currently being tested in a Cirrus, should be certified early 2016 with first 500 sold off production line.

This appears to be a ground up designed and built aviation specific CI engine, capable of running on distilate and Avtur.

I'm hoping it performs and sells:ok:

Jabawocky
20th Oct 2014, 13:50
Eddie, you say low failure rate…..that is true of the FADEC itself, however the FADEC can't discriminate between real anode not.

Perspective has met and spent a few days with a man, possibly Australia's leading LAME in Diesel FADEC's, actually I reckon for sure he is THE authority on them, and he will tell you how much income his company has yielded from stupid FADEC faults. None actually within the FADEC itself.

Perspective, you should know exactly whom I refer……did you ever get to chat with him about this topic? It makes you cringe if you did.

Nite all :ok:

Perspective
20th Oct 2014, 20:49
I have had the opportunity to work with many
Talented and more experienced LAME's than I, but any
In depth conversations about GA Fadec are light on.

Eddie Dean
20th Oct 2014, 21:02
Hi Jaba
Please post more info, if you have it to hand, on the FADAC soft and hard faults of which you speak.
I have heard of the battery back up issue, which can be fixed by using a PMA generator as with turbine fADEC.

D

Andy_RR
20th Oct 2014, 22:26
It's pretty easy to design a really bad FADEC/engine controller and the best way to do this is give the job to a bunch of electronic engineers!

On the other hand, a robust, reliable system starts with a bunch of FMEAs and other dull paperwork exercises, driven by someone who understands both engines and electronics. Since this is relatively rare and especially unusual in the GA/Aerospace industry, its more common to find controllers that react badly to failure modes, of which interconnects are probably the most common factor.

Jabawocky
21st Oct 2014, 02:50
Too hard to cover on prune, but it was not general the FADEC itself, or often not the sensors either, but a connector vibrating or suffering moisture or something but masquerading as a component problem, rendering the plane inoperative and always at a distance of 200nm from the capital city.

And not the same plane each time, across a small fleet.

Andy_RR
21st Oct 2014, 04:05
...of which interconnects are probably the most common factor.

Sorry for using jargon, but I agree with you Jaba! ;)

I have a design concept for a "zero-connector, zero external power" engine management system to plug into a mag hole on a Lyc, but a good friend of mine has advised me it won't meet FAA's interpretation of robustness/redundancy, so I haven't really pursued it. That, and the fact that the market is small and shrinking and noone can make their mind up about what fuel to burn. It's a project highway to grief and nightmares

Perspective
21st Oct 2014, 07:14
I seem to remember quite a lot of installations having
To be renewed, as was not allowed to have a termination
In the system, or at the very least a max of one junction
(737's)
A lot of the problems concerning electrical systems seem
To be able to be put down to connectors/junctions causing
Internal failure upstream in the control module or alike.

As you Say Jab and Andy, remove this from the system and you
Probably remove 90% of the causes of faults and internal
Failures.

Oracle1
21st Oct 2014, 08:16
In terms of AVGAS engines, effort would be better spent on making a magneto that was more "solid state" with fewer moving parts, that still generated its own charge and used very little electronics to time the collapse of the field. Lets face it guys once your trained and familiar three levers ain't that hard to do.

As for this piston diesel that you guys keep raving about. It will never happen, with the advent of nanotechnology and advanced manufacturing the micro turbine will become the standard. Its bad enough swinging four and six pistons of the size and mass in an aircraft engine at a compression ratio of say 9.0 to 1 on average. Now try and do that at 22 to 1 and manage the harmonics/forces/vibration. Why bother when a micro turbine is smooth as silk, will be thermodynamically efficient, more reliable etc etc etc.

Jabawocky
21st Oct 2014, 13:55
Oracle1…..you want PRISM ? ;)

Flash2001
22nd Oct 2014, 00:56
For anyone interested in harmonic problems read "No Short Days" The story of the development of the P&W 2800. Interesting non-integer harmonics etc.

After an excellent landing etc...

yr right
22nd Oct 2014, 01:28
P&W having trouble at the moment with turbine blade between two models 34 & 114 both basically same engine but you can't use the latest blades in the 34 due harmonics.
If you service your mags at the correct intervals as require by the manufacture you rarely have problems with mags. You can't really get any think simpler that them. Why the need for fadec in ga piston engine. Kiss is the way to go. More you place in the more that can go wrong.

People removing glass screens and replace ing them with normal dial instruments due the cost of repairs.

Oracle1
22nd Oct 2014, 10:34
That must be why the automotive industry ditched points in the early eighties?

A magneto may well be reliable but is it durable given you have to strip it every five hundred hours? Only the intellectually deficient or lazy would argue that we as engineers of both the mathematical and physical disciplines shouldn't refine and improve our engineering. Simplicity sometimes cannot provide reliability or durability but refinement certainly can. Refinement also lowers labour costs. Compare the complexity of the human being as a machine as say compared to your ECU and consider their relative reliability.

Good engineering is reliable and **** engineering isn't bottom line

Eddie Dean
22nd Oct 2014, 11:03
Only the intellectually deficient or lazy would argue that we as engineers of both the mathematical and physical disciplines shouldn't refine and improve our engineeringThat is a bold statement, oh Oracle One

Meanwhile back at the FADEC CI module manufactured by Bosch,
Jaba anymore info on the soft faults?

yr right
22nd Oct 2014, 20:22
The magneto is still used today in high prefromance race cars. The mag in an aircraft if you have not notice is completely stand alone. While ever the prop is moving it's doing its job. It light weight reliable with the correct servicing and in aviation terms it's cheap. Requires no out side power which also makes it light plus it preforms ignition in an aircraft engine extremely we'll. it's pretty hard to beat really.

Jabawocky
23rd Oct 2014, 09:38
Eddie,

I thought I covered it in enough detail above.
Too hard to cover on prune, but it was not general the FADEC itself, or often not the sensors either, but a connector vibrating or suffering moisture or something but masquerading as a component problem, rendering the plane inoperative and always at a distance of 200nm from the capital city.

And not the same plane each time, across a small fleet.

However, if you want me to provide the fault codes in the FADEC uploads……. I would have to ask Andrew and I really can't see the point in asking as it is meaningless. If you own one of the affected aircraft chances are you know the best man in the country to deal with them. Discuss with him at your next opportunity. :ok:

nomorecatering
23rd Oct 2014, 11:16
Magnetoes are used in top fuel dragsters for several reasons.

They give the spark energy that is required.

The engines only need fixed timing because they only have 1 operating rpm

They have a life span 1 second more than required, ie 5 seconds.

Eddie Dean
24th Oct 2014, 01:24
Hi Jaba
No problems, I have some experience with auto diesels and am interested in the aircraft CI engine,

Cheers

Ultralights
24th Oct 2014, 01:36
Rotax seam to have the solid state ignition systems pretty sorted...

yr right
24th Oct 2014, 21:39
So when was the last time you had problems with your mags. When was the last time you had your 500hourly service done on the and or o/h. The mag is compact light and extremely reliable if service correctly. Then it's main thing is the fact that it is NOT religant on anything other than the engine turning. And unless you have a gstio 520/550 access is relatively easy. This constant push towards everything new because you have to have it is really unnessary. For most of you that would be lucky to fly 100 hours a year are happy to pay the extra cost involved in supporting the new gear. I would think not.

Things in the motor industry decrease in cost due to the amount of production and atomization. We how ever can't use this. Our aircraft and engines are all hand assembled and as such they can't compete.

Is it really required we change for change stake. And as for a top fuel car useing one rpm yeh sort of but the point is the energy that the mag makes can't be done via electronics for the same weight. And I guess your aircraft while in cruse your not operating a set rpm are you.

Nothing in aviation ever decreases in price. With expection to some after market gear PMA that sell at a reduce cost to original manufactures.

megan
25th Oct 2014, 00:21
due to the amount of production and atomizationSo they blow it up after they produce it? Planned obsolescence they call it. Think you meant to say amortisation.

Ultralights
25th Oct 2014, 05:56
This constant push towards everything new because you have to have it is really unnessary

and this is why General aviation aircraft and engine technology is still in the 1940's


How many Magneto systems go in excess of 1000 hrs without needing any servicing?

opps, my rotax modern electronic ignition systems have... .

yr right
25th Oct 2014, 06:42
We been over this before. Whilst the out side may look old materials have change. The reason why they look the same is they got it right the first time. Power verses weight verses reliability. 1000 hours we'll manufactures say 500 you can't beat the humble Mag for reliability verses weight verses performance. But I sure you all will think you can.

Ultralights
25th Oct 2014, 08:20
so, what your saying, because its works, we should just stop advancing and developing new technologies.? but, if you service it right, then it will be reliable as ever, well, theres the problem, you have to service it to keep it reliable.....


why is it the aviation industry is so adverse to new advances in technology?
why am i driving the last generation of internal combustion engined cars, yet fly a "new" cessna with an engine designed in the 40's and an airframe in the 60's?

i guess the real reason is litigation.... :* but a big part is a perceived fear... just take the Lean of peak arguments... the technology exists to prove otherwise, data doesnt lie, but we refuse to let go of the old in the face of overwhelming evidence...

i remeber the crap i got for flying the then new Jabiru LSA... the plastic fantastic.. will never last, will be useless in 10 years.. so what do you do with it when it gets to 500 hrs? if it lasts that long...

well, 9,000 hours later, i can still hire that same jabiru..

i guess the new tech nockers will refuse to board a 787?