Lycoming, Continental and Rotax [Archive]

MACH082

10th May 2008, 05:50

I would have to say the ole IO-520/550 holds a place in my heart. Nothing like lumping round the bush strips on idle bup bup bup bup and then she sings a sweet song at full noise. Her vocals can become a tad haunting when the smooth pur becomes a howl of protest and they are not the most reliable engine with the pots wanting to eject from the block on occasion, but she will always get you home if you treat her right. She was never made to haul uncle Cessnas biggest mistake, the strteched scenic limo, she felt a litttle out of her league slung all lonely up there, but in a bo or a strutless kimberley taxi she was in her element, especially when slung of each wing pushing beeches finest piston achievement, the mighty baron, even if its an ergonomic nightmare!

The TIO-540. IO-540 and O-540 dont have the snarl of the conti, but have never let me down in the many hours i have flown on them. Not even a mag failure touch wood.

the 520/550 all the way!

Now how bout we talk jets :)

VH-XXX

10th May 2008, 06:56

Rotax 912/912s & 914's simply don't ever stop if you keep the fuel and water up to them. There have been failures in the past but they are usually few and far between.

A 912 requires a head tighten at 400 hours, other than that pretty much nothing is required till 1,500 hours other than oil and filters. On condition from then to easily over 2,000 particularly if done quickly in a school environment. Over time is a different case as the radiator hoses will perish over time.

There have been some 912 failures but they were usually were pilot / maintainer at fault. There was a recent failure of a 912 resulting in 2 deaths, but this was prop related apparently.

I purchased a 912 at 1,000 ahours nd did another 500 and did nothing more than change the oil, filter and coolant.

It seems unusual to cruise at 5,000 rpm but that's just what they do.

The Jabiru is a far smoother engine than the Jabiru and most others on the market. They have a little way to go with valve life and mixture indiscrepencies but other than that they are a good unit and the 6 is more powerful than all Rotaxes so they have their niche in the top end RAA / LSA range.

Horatio Leafblower

10th May 2008, 10:23

pretty much nothing is required till 1,500 hours other than oil and filters. On condition from then to easily over 2,000 particularly if done quickly in a school environment.

When I was last a RAAus CFI (9 months ago) the advice I had from the Ops Manager was that tha RAAus could be flexible on many things.

One thing they could not be flexible on was TBO on the Rotax in the school environment.

NO "on condition" allowed. :ugh:

Mach E Avelli

10th May 2008, 23:34

I know one guy bought a 1500 hour Rotax from a flying school and has run it another 500 hours - not in a commercial operation I hasten to add. Oil consumption is almost nil and he has the oil analysed at every 50 hour oil change. All perfect so far.
As mentioned, the key to good engine life is regular use, but that applies to all engines - 2 stroke lawnmowers are a good example. They go forever because we are always cuttting the grass it seems. Marine engines often give trouble because they only get occasional use.
Back to Rotax engines. A weekly ground run is not the answer. They need a good flogging which is best replicated by at least a few circuits or even better a good climb for an hour's cruise. At 15 lt/hr it's as cheap as flying can be. Cheap being a relative term in this case.

VH-XXX

11th May 2008, 00:33

Horatio Leafblower (http://www.pprune.org/forums/member.php?u=67964) the ops manual was modified last year to allow operation of RA-Aus aircraft "ON-CONDITION" similarly to that of GA opeations. Whilst the ops manager at the time may have been operating by the book, it wasn't in the spirit of RA-Aus getting people airborne economically so the board quickly changed the regs.

VH-XXX

11th May 2008, 00:38

Will be interested to see how the new GA mini Partenavia / Tecnam goes with it's 2 x Rotax 912's 100 HP's. They are quoting some ridiculously low fuel burn figures. A good aircraft to keep an eye on. Would be interested to see how it goes with single engine operations with 4 POB at MTOW @ 100 HP max for 5 minutes.

Interestingly Cessna tried the Rotax for their new Skycatcher 162, but went back to the Continental to stick with what they know. Then again probably not a bad idea considering 'everyone knows the Continental' in the GA world and adding a water cooled Rotax might have been a bad idea.

Jabawocky

11th May 2008, 03:58

Lycoming IO-540D4A5 rated at 260 hp

Any one have any useful comments on these?

J

Bendo

11th May 2008, 06:29

XXX

If that's the case I can imagine there will be some "high time" Guzzles that have suddenly increased in value! :ok:

*High time Guzzle was anything over 2500hrs :ooh:

RadioSaigon

11th May 2008, 07:14

Lycoming IO-540D4A5 rated at 260 hp...

and here was I erroneously believing all the I-prefixed 540's were 300hp! Live & learn, live & learn... what are they likely fitted to Jaba? I've spent a helluva lot of time behind/beside the vanilla O-540's (260hp) of various variants and have a helluva lot of respect for them. A damn fine engine IMO.

Thinking the IO-540 would have to be damn near as bullet-proof, surely! Only developing the 260hp, presumably still a max RPM of 2700, should be a good mill! From what I've read of it just now, it doesn't seem to be reamed at all...

Interested in others opinions of the mill..

ForkTailedDrKiller

11th May 2008, 07:35

Jaba, do yourself a favour!

Get out ya tin snips and soldering iron - and stick a IO550 in her !

Dr :8

VH-XXX

11th May 2008, 07:52

That's right Bendo, or Hiratio or whoever you are posting as on the day... :=

Apparently all the 152's out there have gone up in value in anticipation of RA-Aus getting 760 kg's. The word is, between 2 months and 2 years before it happens.

solocmv

11th May 2008, 08:48

Hey XXX

Does the higher stall speed for the 152/Tom make them in elegable for
RA-Aus even with a weight lift to 760KG ?

Cheers,
Solocmv.

VH-XXX

11th May 2008, 09:10

Stall speed for RA-Aus must be less than or equal to 45 knots dirty, so at 43 knots the 152 fits in easily.

Interesting question though in that you'd have to assume that with 760 kg's would come a stall speed upgrade.

Eg a J230 Jab airframe is currently 600kg's and stalls at 45 knots, however capable of 700-750 kg's, but the stall speed would be higher, say 48 knots so an increase would be desireable and that's just a good example of an affected aircraft.

ForkTailedDrKiller

11th May 2008, 11:24

Caught ya drift CTR!

Hey Doc, so the I0550 is the way to go in V35B too?

Yeah, I'd like to try an IO550 in the FTDK!

have you come accross/got VistaNav - any good?

Looks good on paper! I tried to buy VistaNav last year but they won't sell it outside the US cause they say they don't have the database to cover Oz.

Have also tried the TrueMap software - don't waste ya money!

Dr :8

Capt Wally

11th May 2008, 11:40

I used to fly/hire an old PA28-140, 150 hp lyc O320 that just kept on going. Hate to think how many real hrs it had on it. The engine would rattle along all day & I mean rattle! I recall some years latter that the same A/C still had the same engine (not O/hauled) & still going strong with about the same eng time, must have been the tacho cable, just seemed to fall off most of the time probably!:E
Would be interesting to know how many 'bush' planes out there in 'squeal like a big boy' country that have engines a 'tad' over the recomended o/h time, not withstanding 'on condition'.

Lyc's the way to go & with WW2 technology why fix sumfin' that ain't busted?:ok:

CW

Ultralights

11th May 2008, 11:41

i have my eye on a nice Ultrabat, just waiting for the 760Kg weight for RAAus

Flyingblind

11th May 2008, 12:10

Thanks guys for all your informative posts, very interesting reading and its the type of discussion i was hoping for.

I think you nailed it on the head CTR with your quip re 30 year old (engine) design, will it take the Chinese entering the GA market or a bigger version of the Rotax (due to the phenomenal growth in LSAs and their forthcoming increase in MTOW) to spur the big two into updating their technology?

As the price of fuel heads north at a substantial rate of Knots, more technologically advanced (and emission sensitive) engines are required, why this hasn't happened yet beggars belief!

I guess it all comes down to the old saying "if it ain't broke...don't fix it!"

Deaf

11th May 2008, 13:35

The J250 would meet the 45kts

Just at a guess if the RAA goes to 750 this would only apply to new a/c (or ex GA a/c already registered at the higher weight) rather than the 544/600 suddenly OK for 700.

youngmic

11th May 2008, 13:59

Clearedtoreenter,

Whoa there boy, you might want to check your pea shooter before you commit.

Now granted computers and a electronics have done wonders for the internal combustion engine, but lets not forget the basic mechanical principals all herald back to the "30's" and there is not much new under the sun.

The basic design of the Lyc's and Continentals (or Nentals as some wag put it) or Rotax and Jab's for that matter is pretty bloody good.

Check out the BSFC's against an auto engine, you might be surprised. A properly set up aero engine at .39lb/hp/hr against an automotive engine returning between .42 to 1.0. And there's your emissions answer as well.

I'll give you the mag comment, and even constant flow injection is a little dated, but it works surprisingly well considering, as do carby's if you just want to run an engine in a narrow rev range, as we do. As for push-rods, well it's not a bad way of doing business in a slow revving engine, and oil consumption is governed by laws which remain unchanged since the 30's and apply to your Corolla just the same.

Both Rotax and the Jabiru's return very close to the same fuel burn /hp as do Lyc's and Nentals, when set up by a proper mechanic.

As a thought process strap your Corolla engine into a boat and run it near flat out. How far do you think you'll get?

There's a surprising amount to be learned from the olden days of suck squeeze bang blow wisdom.

M

Wombat35

11th May 2008, 19:53

Ahh I'm a Pratt man myself!

Yeah my O320 sounds good and never breaks... but that's no fun...

Give me 14 130Cu" pistons all working in blessed harmony with a blower any day :ok::}

Ultralights

12th May 2008, 08:19

http://Pamuva1.smugmug.com/photos/122668232_FRmNk-M.jpg

Capt Wally

12th May 2008, 08:50

SNOWMOBILE RIGHT?:}:}:}
That's the only place I'd fell comfy with a 'toy' engine like that, well maybe in a 1/2 scale R/C model:-0)\

CW:ok:

VH-XXX

12th May 2008, 12:38

Hats off to the Australian aircraft comany manufacturing and shipping out more than 4 times this many every month!

http://users.netconnect.com.au/~njah1/engines.jpg

Deaf

12th May 2008, 16:09

"Ahh I'm a Pratt man myself!"

Nice donk but who can afford the oil

Wombat35

12th May 2008, 21:29

They use oil? :)

Nothing like getting home after a hard half hours flying, taking off the white shirt and seeing a

"GREAT BIG BLACK DRIP of P&W love" down your back... :p

Still, the sound of 48" makes up for it!

Capt Wally

13th May 2008, 02:18

I didn't realise that there where that many SNOWMOBILES around!:}

CW:ok:

Murray Cod

13th May 2008, 06:30

I think Mach E Avelli might be wrong about the outboard motors. The reason they were not reliable is because their American. All of the new jap outboards are outstanding. The Yanks get lazy when they dominate the market. The movie "the Texasa chainsaw massacre " must have been ficton as the Mculloch (american) chainsaw actually started , the hockey mask was probably canadian.
Mind you , the IO 540 never let me down. It's just ancient!!
Maybe Honda could make 6 cylinder and call it an American name , beastmaster, or some thing. They could even engineer an oil leak for Wombat.
MC

mustafagander

13th May 2008, 10:30

Keep in mind, fellows, that no automotive engine is designed to, nor is capable of, running continuously at fixed RPM for any length of time. It's all about oil!!

ForkTailedDrKiller

13th May 2008, 11:17

I figure that I am getting 0.44lbs/hp/hr out of the IO520 in the Bo.

Dr :8

Ex FSO GRIFFO

14th May 2008, 01:25

G'Day Doc,

How's that IO-550 in the 'Holden of the sky' shaping up??

How much faster / fuel burn than a 'normal' 210??

Regards,
Griffo:ok::ok:

Is that one, one of those "Atlantic Conversion" thingies??:ok:

sms777

14th May 2008, 09:32

I do have an argument there mate!
There have been a few proven conversions out there involving automotive engines eg. Oliander V8 Chevrolet 454 engines fitted to Queenair airframes in Canada back in the mid 80's with full approval.
I do not know if you remember the Vickers Vimmy replica that flew all the way from England to Australia with god knows how many stops on the way due to speed but made it to Bankstown with two (again) V8 454 Chevrolet truck engines fitted. Low revving engines with no problems at all. I have seen internals of several Lyc/Con engines many times and they are no different to internals of most high performance automotive engines.

And when it comes to oils, it all depends on the application.

sms777

14th May 2008, 10:34

Wait till you start your endorsement on a Chieftain and see which way the "other prop" turns! Do not freak out because i warned you!
We are all mad after all.:ok:

Fred Gassit

14th May 2008, 11:23

Orenda engines never delivered, derived from the cadillac northstar v8, 100 million dollars spent trying to make a car engine into an aircraft one.
Take another look at an aircraft crankshaft vs. a cars, they are very different.
As it has been stated many times on this and other threads, try and find an engine that reliably makes it to TBO (a decent time interval!), is rebuildable (not thrown away) and runs wide open for thousands of hours in all temperatures while delivering up to 300hp.
They might seem expensive but the alternatives end up just as costly.
Isnt the 100hp Cont. up to 2400hr TBO?

Some of the big recips from the 50's delivered low .3s' on Specific fuel burn, not too reliably at times admittedly.

sms777

14th May 2008, 12:01

I would like you to come and look at some of the crankshafts that i work with. They are in a 7000 hp top fuel drag race engines that run on pure alcohol with a shot of nitro fuel to top it off at a conservative 9500rpm. I think they are exposed to a "little more load" than your IGSO 540 crank.
And guess what? They are made out of the same batch of 5140 chrome moly steel with the same machining tolerances.
So do you think that your 1940's dated aircraft engine can out perform todays quality? Think again.
Remember what happened to Titanic????

saabsforever

14th May 2008, 12:33

It is interesting that from time to time very efficient and powerful well proven car engines are converted for aircraft. Porshe developed and certified their 3.0 litre 250 odd hp with new duel ignition and crankshaft. Put a gearbox on it and was sold as an option on Cessna and Mooney about 10 years ago. Few sold because the fuel consuption was no better than the 'old inefficient' ones, weighed as much, cost as much and was more complex. Had to do 5000 rpm instead of 2500 and then be geared down.Soon dissappeared. Likewise Toyota developed their 4.0 litre v8 ( a supurb light and powerful engine) for aviaton but never marketed it for the same reason. Car engines are not designed to run at more than about 30% power for more than brief periods, hence the cooling issues when running at high power in aircraft. Boats may be different as plenty of cold water is available. The old air cooled low revving high torque pushrod 2 valve engines that we have used for the last 40 or 50years are simply very good at what they do. But a bit if modern ignition and fuel injection would seem overdue

sms777

14th May 2008, 12:58

I can relate to that every way.
Forget about tacho time, how about the good old gear switch?
Every aircraft owners best friend. " Just dump the gear 20 nm out( my old boss used to say) it will save the engines, no worries".
Hey, it is legal!

Peter Fanelli

14th May 2008, 13:07

I do not know if you remember the Vickers Vimmy replica that flew all the way from England to Australia with god knows how many stops on the way due to speed but made it to Bankstown with two (again) V8 454 Chevrolet truck engines fitted. Low revving engines with no problems at all. I have seen internals of several Lyc/Con engines many times and they are no different to internals of most high performance automotive engines.
Yep, it ran quite well on a pair of old technology V8 Chevrolet engines, but the high tech BMW engines that were fitted when it was originally built were a disaster as aircraft engines.

I would like you to come and look at some of the crankshafts that i work with. They are in a 7000 hp top fuel drag race engines that run on pure alcohol with a shot of nitro fuel to top it off at a conservative 9500rpm. I think they are exposed to a "little more load" than your IGSO 540 crank.
And guess what? They are made out of the same batch of 5140 chrome moly steel with the same machining tolerances.

Will they run at 75% of their rated power for around 2000 hours without a rebuild? Or are we expected to fly for 10 seconds at a time and then pull it down for an inspection?

Ultralights

That's a mighty small propellor on that engine, and so many blades to dress too.
:}

Ultralights

15th May 2008, 09:34

yes, ducted fan! very efficient! :}

Capt Wally

15th May 2008, 10:25

yeah 'sms777' I recall the same being asked of me to lower the 'dunlops' a tad before the normal extension, say 30 miles out & enjoy the almost free ride!:)
I think some of the main differences from aero engines to auto engines is the largish capacity (360 cubes for just 4 pots for Eg) & the low revving designs that made them last. Remember that at around 2400 rpm for most of it's life an aero engine would be doing about half the work/wear to a small capacity high revving auto engine. These metal parts are in constant contact with each other (via a thin film of that slippery stuff) & if they are doing it twice as much (as in auto engines) then their bound to wear out quicker or present problems prematurely. Like it's been said, would an auto engine be able to sustain 75% pwr for most of it's life say 2000 hrs?, doubt it somehow.
Auto engines produce rapid peak power mostly at & for brief intervals where as aero engines produce there high power almost all the time.
Horses for courses, i wouldn't wany an aero engine in my car, slug of an old thing it would be & I also wouldn't want an auto engine in my plane 'cause where would ya put the accelerator pedal?:}

CW

Ultralights

15th May 2008, 13:05

why dont we see more rotary engines aircraft? plenty of power, very smooth, light weight for their output, and with a 3:1 difference in the crank shaft/rotr speed, they would be turning relatively slow. 3000 rpm crank speed =1000 rpm rotor speed. barely above idle. and rotary engines become very efficient when at a constant RPM

not only that, the inherent reliability, when 1 rotor blows, the engine will still produce 50% power.

Peter Fanelli

15th May 2008, 14:44

flytheengine.*************/2007/10/largest-lycoming.html

Those who think such things as variable valve timing are new high tech stuff should read the third paragraph.

OK well I guess the new owners of pprune have some reason to censor that link, you'll have to add the http:// and fill in ************* yourself.

Ok, well how about you have to add blog and spot without the and in the middle and .com to make the above link work.

Damn this net censorship in pprune is getting old.

http://en.wikipedia.org/wiki/Lycoming_R-7755

Capt Wally

15th May 2008, 22:41

'ultralights' am not too sure why rotary engines aren't used in planes, but if a rotor did 'blow' in a twin rotor design I think you will find that the loss of power assuming it would still run at all would be far greater than 50%. That goes for any multi cylinder combustion engines. You see the resultant drag from the non power producing parts would slow down the operation of the good rotor by friction/drag alone not too mention possible out of balance issues. Still yr correct they are a smooth operating engine but never really took off (no pun intended) because they where quite thirsty for their power output & the seals on the rotors in the original designs where of concern as well. Just what I recall about them during my apprentice days.

CW

Ultralights

15th May 2008, 23:01

i have a rotary powered car, a nice old rx7, the engine did 330,000 km before it failed, and when it did, it was a result of the housing liner, the chomium/steel part wearing through, once this happened, pieces of the liner seperated and destroyed all the tip seals of the rotor, this happened when i was in Newcastle, the engine still provided enough power to drive to southern sydney, at freeway speeds, and easily kept up with traffic when i reached syd, the advantage of when it fails, is that id destroyed all the tip seals which stopped the rotor compressing its air/fuel charge, which allowed to spin relatively freely. so even when the engine has lost 1 rotor it still provides substantial power, enough to get you out of trouble if it fails in flight, well, better than a complete loss of power anyway.
the only adverse effect of the rotor failing was a constant missing sound from the engine, it was still balanced, no unusual vibrations, just a little higher fuel consumption.

there are quite a few RV aircraft flying in the US, and i know of 1 in OZ, i just wish there were more of them. especially now wih the Renisis rotary engine being more powerful again than the old engine, and 20% lighter.

sprocket check

18th May 2008, 00:37

Couldn't help noticing the Sting crash ATSB report comment in FSA. Two died due to a crankshaft failure on the Rotax.

Report mentions no fault metallurgical or otherwise. Any one with more info on the cause of failure?

Is this just a really light duty design?

I hear it is a 1500 hour replacement item? Is this true?

What is the history of crank failures in Lyc/Contis?

sc

ForkTailedDrKiller

5th Oct 2008, 06:39

wondering if any of you pilots with experience can tell a few tales about your favourite engine

I've just done my 6 mthly logbook update!

Been sitting behind the Continental IO520-B in the FTDK for just over 600 hrs - about 89,000 nm!

That's equivalent to 4 times around the world - along the equator! Kind of staggering when you look at it in those terms.

Hasn't missed a beat - just purrs along!

Dr :8

Oracle1

27th Jul 2013, 10:13

Jabawocky

This is probably a more appropriate thread to discuss the rotax.

Rotax figures for the 912iS as per

http://fahrzeugtechnik.fh-joanneum.at/workshops/2012-2013/2013-02-27-Rotax-912iS.pdf

show the figures of between .41 and .42 in cruise and .477 at full power

Performance
Maximum Power*
(5 minutes) 100HP / 73.5KW @ 5800 RPM
Maximum Power (sustained) 95HP / 69.0KW @ 5500 RPM
Maximum Torque 94ft-lb / 128NM @ 5100 RPM

If your Lycoming is returning .4 as you claim which I assume is LOP then the figures are almost identical given similar fuel management regime,

The operator manual for a 300 HP Lycoming IO-540-K, L, or M series engine shows a full power fuel flow of 24 GPH which is a BSFC of 0.474 ...

I repeat there is no such thing as a free lunch, the figures are almost identical. Considering you enjoy the advantages of scale and no gearbox losses it is a remarkable achievement for a little engine.

As for dollars per horsepower I agree the Rotax is more expensive and Rotax has become greedy but to be fair we are paying in euro exchange rates.

Aussie Bob

your argument re head temperatures is immediately proven wrong when you consider that a Rotax head operates at 85 to 95 c as opposed to 162 c for your heads. Add in thermal momentum for the liquid cooling = a more stable valve train. You might have got somewhere with arguments such as more cooling drag, increased complexity and weight but it is proven fact that liquid cooled engines enjoy more stable operating temperatures

Aussie Bob

27th Jul 2013, 10:21

Thank you for dragging up this thread oracle. I have not seen it before and will read it in detail ...

Oracle1

27th Jul 2013, 10:27

Look here also for real world comparisons as to operating costs to other engines in its class,

Rotax Aircraft Engines - Fuel Economy (http://www.flyrotax.com/enginesImpressum/compare-to-competitionImpressum/fuel-economy.aspx)

nomorecatering

27th Jul 2013, 10:27

so what is the difference about aircraft crankshafts as from automobile crankshafts. There is obviously something that makes autoconversions not very successful. I just cant find what it is. How can a crank that turns reciprocating power into rotary power have such different results.

Oracle1

27th Jul 2013, 10:33

aircraft engines are designed to turn at slower RPMS because the speed is limited by the prop tips going beyond the speed of sound. Automobile engines develop rated horsepower at higher RPMS and therefore need a gearbox to spin the engine at enough RPM to develop rated power. Building a successful gearbox and beating torsional resonance is no mean feat as discovered by lycoming and continental with G0 300 and the geared 6 cyl in the navajo cheiftain. Hats of to the german engineers for making it work very well in the rotax.

Tankengine

27th Jul 2013, 10:44

Even assuming no gearbox to reduce revs the automotive crankshaft is not designed for the sideways loading that a prop would give it.
Much more leverage from a prop than the straight drive to a flywheel or torque converter.

Oracle1

27th Jul 2013, 10:50

Correct no axial loads are applied to an automotive crank hence the large plain bearing at the front of an aircraft crankshaft, however a gearbox absorbs the axial loads if correctly designed

Ultralights

27th Jul 2013, 14:49

Rotax 912 crankshafts are pretty much indestructible, some are 1500 hr TBO, but the last 5 to 10 years they have been 2000hr TBO. a 1500 hr tbo engine can be upgraded to 2000 hr with the completion of a few Service bulletins.
the tbo cost is substantial, as the crankshaft, and piston conrods are manufactured as a one piece assembly that cant be disassembled. they do not use copper slipper type bearings, but sealed for life roller bearings.
Unlike continentals, the cylinder heads can be easily separated from the barrels for overhaul of each component. i am lead to believe that the heads on continental engines are screwed onto the barrels to complete the "jug" assembly, and ove these are screwed together, cannot be separated. (could be wrong though)

yowieII

27th Jul 2013, 15:18

Building a successful gearbox and beating torsional resonance is no mean feat as discovered by lycoming and continental with G0 300 and the geared 6 cyl in the navajo cheiftain. Hats of to the german engineers for making it work very well in the rotax.

Just to be sure, the Chief had the TIO and LTIO 540, the Titan has the GTSIO 520..

dubbleyew eight

27th Jul 2013, 15:24

ultralights the engines have totally different overhaul philosophies.
you are trying to compare apples, pears and oranges.
yes they are all fruit but none are the same.

I would not ever change my Continental O-200A to any other engine.
it is totally absolutely trustworthy.
btw TBO is a meaningless concept in privately owned cat B aeroplanes.
the engines are run on condition.

overhauled parts are for schmucks. real engines work on replacing worn bits.
I have sitting beside me 4 new O-200 cylinder assemblies. for $5200 I get new pistons, new rings, new wrist pins, new cylinders, new heads, new valves, new valve guides, new valve springs, new retaining clips. what I carry over from the old cylinders are the bits that don't wear hardly at all. rocker assemblies and such.

there is a flying school in florida that ran either lycomings or continentals on condition. with very regular flying one engine was run for over 4,000 hours.
dont believe the dinosaur rubbish. it will take you down the garden path.

Ultralights

28th Jul 2013, 01:48

the dinosaur rubbish i believe, is the fact the lycomings and continentals still run a magneto! carburettors disappeared in cars decades ago!! even so, carbys can be made to automatically adjust their mixture in reference to external air pressure, or lack of it,
why do they still use a manual mixture control? im still a little surprised Rotax have just come up with a multi point EFI. not exactly a new invention.

Aussie Bob

28th Jul 2013, 04:32

Ultralights, it is easy to build a carby to automatically adjust mixture but with manual mixture control and a good EGT gauge, far more accurate adjustments can be made from on board. You may well want an engine that dumbs down everything but I don't. Tell me, how do you run LOP with auto mixture? Sure, magneto technology is old, but it sure is simple and in some ways I would prefer it to a bunch of electronic black boxes.

As a final note, have you ever seen just how easy it is to prop start an aircraft engine? My O360 will start with a barely perceptible movement of the prop. It is stunning to see just how easy it can be to start under the right circumstances. Using the mixture to stop the engine provides a margin of safety over and above ignition switches.

LeadSled

28th Jul 2013, 06:31

There was a recent failure of a 912 resulting in 2 deaths, but this was prop related apparently.

Folks,
If this is the loss I think it is, the problem was an interaction between the type of prop. fitted and the engine, the result was a serious mechanical failure in the engine.
Always read the engine manufacturer's words of wisdom on props. very carefully, harmonics can ruin your whole day.
Tootle pip!!

Oracle1

28th Jul 2013, 07:28

This failure was allegedly caused by a previous operator over stressing the crank by turning up (coarse) the variable pitch prop and raising the BMEP beyond limits. (time trial racing) The subsequent buyer then suffered an engine failure when the crank failed and a forced landing was unsuccessful. I have seen the photos of the crank in the report to the coroner (original copy by the author) and one of the recommendations of the coroner's report was that all RAA aircraft running a variable prop must be fitted with manifold pressure gauges.

Never seen a failure like it before or since

Jabawocky

28th Jul 2013, 11:23

Course pitch effects BMEP ?? Peak pressure slightly, but I can show you these effects on dyno runs, and it is barely worth discussing. :ugh:

Please explain that, just because a coroner allegedly accepted it does NOT make the laws of physics change.

The reason the two died was because the pilot screwed up, big time. End of story.

The reason the crank failed was most likely due to significant problems induced by the deceased owner and his amazing maintenance problems. Read the coroners report closely and see why this is true.

The alleged damage from any time related records has nothing to do with it.

This was not a Rotax fault, nor the previous owner. The previous owner might have had some paperwork and regulatory issues, but the crank failure was not paper induced.

Plenty of people have survived a engine failure, despite crank failures, it was what they did after that that mattered.

How any of this can wind up BMEP on a Rotax is .....well tooth fairy stuff.

And a MP gauge in a NA aircraft is of very little value anyway, apart from calculating % power when ROP.

tecman

28th Jul 2013, 11:47

I'm not going to fuel what's coming across as essentially a religious debate (being happy to fly routinely with a Rotax 912 and the more traditional engines). However, Aussie Bob's assertion re unintended starts needs correction. With the supplied Rotax ignition system, you cannot in fact hand start the engine: it needs to swing at a few hundred rpm before the electronic module generates any spark at all. As a matter of fact, I've tended to regard this as a disadvantage.

I'm also quite happy to use a mixture control but I'd be surprised if I could improve much on my typical 15lph in the Rotax.

Oracle1

28th Jul 2013, 12:02

Jabawocky

your tone is becoming a little extreme isn't it? Keep in mind I have a lot of hours on these engines with my signature on it. When was the last time you pulled one to bits? Those really in the know are aware of the aircraft's history and I have cleaned up the mess before of the previous owners attempts at maintenance on aircraft in commercial service, done with no entry in the maintenance manual. Yes the pilot screwed up the landing but he is not here to defend himself is he?
Everybody knows what happens when you try and hill start a vehicle in 5th gear

Still claiming your naturally aspirated lyco is making .4?

Jabawocky

28th Jul 2013, 12:08

Explain your claim on how prop pitch has made a detrimental effect (increase) in BMEP.

I can calculate the BSFC really easy of my IO540 thanks, and show you the DATA.

How about you do the same?

Oracle1

28th Jul 2013, 13:04

The brake mean effective pressure differential (BMEPd) can be experimentally calculated if we know the engine power available at the crankshaft (brake horsepower, P) and the measured volumetric flow rate (Qm) of the air entering the engine's intake system:

BMEPd = P/Qm

we know from calculating the stings time over a set course that the engine was run at maximum power not max continous for an extended period of time so we know that BMEP would be higher than normal. Read my post carefully Jabba I did not say that the coarse prop caused the failure, I said the prop was coarsed to take advantage of the extra power and maintain a higher speed brought on by a higher BMEP over time. Yes peak pressures would have increased but as we have not got a dyno run of a rotax I think its a moot point don't you? Are you in a position to infer that any level of change in peak pressure wont affect the operation of a crank especially its harmonics and given we are already at higher than normal BMEP and this engine is running a gearbox?

RE MP gauges Q is a function of MP pressure and therefore gives an indication of BMEP.

Back off mate it doesn't make for a friendly forum:=

nomorecatering

28th Jul 2013, 13:12

Would the standard Continental and Lycoming engines benefit from the application of direct fuel injection and a small increase in compression ratio.

The Lycoming rep at the airshow told me that the Ie2 series full FADEC engines have not disappeared, just that the engines are being prepared fro military use and the US DoD is bankrolling its development, after which it will be released for public purchase. I belive the Ie2 does use direct injection.

How efficient are the 2 valve cylinderheads on standard C & L engines. In light of todays complex 4 valve , pentroof, stratified charge, tumble swirl cylinder heads of todays automotive engines, the aircraft cylinderheads seem very plain and low tech/inefficient.

Any comments?

Jabawocky

28th Jul 2013, 13:16

Maths time.

52LPH or 81.4lb/hr
HP=213
BSFC 0.382

Now this is at 82% power and as the HP drops off, the fixed losses take a bigger % effect, so at 75% 0.4 is probably correct. But this photos is at a higher power.

Plenty more DATA where that came from.

Oracle, this is not OPINION.You have an opinion, I can have an opinion, but DATA does not.

Confucius say; do not tell a man something impossible when he already doing it.

Do you want me to do some O-360's or IO520's or IO550's, or O-320's. I have the data?

My apologies if my tone seems extreme, I thought it was more focussed on the absurdity of a coroners report and much misinformation backed by opinions of the ill informed, including whoever made the claim about the BMEP:confused:

Oracle1

28th Jul 2013, 13:29

I apologise as well we should all be here to learn. ok how are you arriving at the horsepower figure of 213 I might learn something. BTW has a coroner ever said anything sensible

Jabawocky

28th Jul 2013, 13:40

Was the extra RPM from running a coarser pitch or finer pitch?

Was the extra HP achieved by extra RPM? Same BMEP but more RPM?

Think about this for a minute the MP could only be ambient less induction losses. So how did the BMEP get increased so drastically? And how did a coarser pitch do this?

The max power of the Rotax is what 5800? and max continuous is 5500 or something? The peak torque generated is sub 5000 rpm, so from that the conclusion can only be the peak pressure and peak BMEP is not at 5800 RPM at all. Thus any prop pitch that derives an RPM in the max continuous range will result in a higher BMEP anyway.

If one used a finer pitch prop, to extract max RPM and thus max HP as the airspeed increased what would have happened to prop efficiency? So why would the pilot do that too? To go slower?

If my memory serves me correctly, the time was over the ground so tailwind had some influence, so in the accident aircraft calculating power required etc without knowing the winds would be a very in-exact science would it not?

The crank failed from the deceased owner operating an engine with severe out of balance states, nothing was documented well in scientific terms other than the owners notes conferring with the supplier, and the actions thereafter did not inspire me with any confidence.

I have had no contact with the supplier nor deceased, but I have read the reports including those prepared for the coroner. None give me the impression the Rotax or its previous owners use were to blame. The deceased owners input is another matter.

PS Oracle no problem :ok: Its late will explain more tomorrow.

nomorecatering....same, time for zzzz but I do have some useful info on that too :ok:

Sunfish

28th Jul 2013, 20:04

Here we go again - conflating about Five different issues....

1. Why don't car engine conversions make good aircraft engines? Blah blah and by implication why do aircraft engines cost so much?

The answer in Two words is duty cycle. - the actual time at horsepower over the expected life for the engine. A Holden Commodore may be advertised as developing "200 horsepower" (say), however it will only be required to generate that amount of horsepower (if it can) for mere seconds during accceleration, in fact at 100KPH the car only requires about 19 hp to overcome rolling and air resistance.

Contrast that with an aircraft engine which is required to generate between 55% and 100% of its advertised horsepower every flight for the term of its natural life. This is a whole other world of durability.

To put that another way, yes, you can get 400 hp out of a turbocharged intercooled Subaru engine, but not for long, and certainly not if you leave it parked in the weather for months between operations.

Even more extreme, consider marine diesels of any size. My yacht has a 13HP Volvo Penta that can operate full throttle all day, all night (2100 rpm) and has done for 41 years with only injector work - but its 385 lb of good swedish cast iron.

2. Why don't aircraft engines use four valves per cylinder, pent roof combustion chambers, overhead canms,variable valve timing, electronic fuel injection, electronic ignition and a host of other automotive technologies? The answer is because they don't need to.

Your car has to deliver power across a rev range of say 2000 to 4000 rpm while producing acceptable fuel economy and pollution levels. What is your aircraft engine rev range between full power and minimum loiter/ cruise? 2100 to 2750 rpm? Say 650 revs? Lycoming and Continetal don't need all that extra weight to optimise for that rev range. Simplicate and add lightness.

Yes, you could build an engine that would use all that technology to produce say !000 hp on takeoff and then turn down to say 200hp in cruise and the aircraft performace would be spectacular.....once you had worked out how to fit a Ten foot diameter propeller and the triple slotted flap arrangement for the tiny wings to obtain an acceptable stall speed on approach.

3. Why have a mixture control when carburettors can be made to compensate? Blah Blah.

Read the Rotax and Jabiru web forums about the problems with allegedly "compensating" Bing carbs and the ensuing misery of cracked rubber, air leaks, needle positions, jet sizes, cylinder balancing, etc. Some people even modify the carbs to regain control of mixture.

4. Not being able to hand starting a Rotax? Lethally Dangerous Myth Hand Propping a Rotax 912 - YouTube

5. The Rotax 912iS fuel injected engine? This is actually a very different beast from the 912ULS, exactly how different I may eventually find out. Jonathan Porter in Africa has been reporting fuel flows around 12 -13 l/h in cruise.

The engine uses a purpose designed ECU arrangement where everything is redundant, there are two oil cooled alternators, one for the engine and one for the aircraft systems in the engine with automatic fail over. eight injectors and most interestingly four EGT probes which makes me think that this system is a little different from your average Bosch injection. The torque curve now also approximates the propeller power curve.

6. Manifold pressure gauges with constant speed propellers? How else are you going to comply with the manufacturers explicit operating instructions?

7. The fatal crash? Apparently evidence was presented that the crankshaft geometry had changed due to some slippage between the built up components that destroyed the geometry. This had manifested itself in a history of unusual vibration. Ultimately the crank failed.

The cause of the crank vibration, if I remember correctly was atrributed to mishandling of the engine or perhaps a prop strike, but the actual persons involved was unclear.

There, I hope I have offended everyone.

Typhoon650

28th Jul 2013, 22:48

I'd just like to point out that auto engines are not near as frail as many here are pointing out.
Many, many manufacturers randomly pull an engine out of production and subject it to extensive, punishing dyno work. Even in the 60's, Chrysler would run production V8's at max rpm/load on dynos to the point of failure or 1000 hours often easily going well over 1000 hours with no failure.
Let's not even start on plain old auto engines which are converted for marine use which run at a constant load and power setting for hours on end.
Certified aircraft engines are great things, they are light, simple and reliable, but they are not even close to being optimised for what they do. They are old designs optimised for what they have to do, but no way are they an example of the perfect solution for the job.
The only reason they are still what they are is certification costs and lack of manufacturing volume to justify new designs.

tecman

29th Jul 2013, 01:58

Sunny and Bob, let me swiftly and gracefully concede the point on the Rotax hand prop. As Dr Johnson might have said, it wasn't done easily but you're surprised to see it done at all. I definitely can't do it with my 912S2, with an exercise in trying some time ago resulting in no spark at all and a lingering case of cricketer's elbow. Admittedly, the S2 has various accessories that may make it harder. There may also be differences in electronics modules but, for the record, I always regard a prop of any type as live. And, as an observation, these days I see fewer new pilots doing a dead-cut check on shut-down of the magneto ignition engines. Having once identified a floating ground problem in a club aircraft it's not a check I skip.

owen meaney

29th Jul 2013, 04:49

Course pitch effects BMEP
Would increase of prop pitch increase BMEP?

Aussie Bob

29th Jul 2013, 05:00

Tecman, another thread worth a read (http://www.pprune.org/private-flying/477542-rotax-hand-swinging.html)

Not an easy to prop start engine but it is nice to know that it can be done if you are stuck.

Jabawocky

29th Jul 2013, 05:59

Owen, no it doesn't.

Oracle1

29th Jul 2013, 09:12

Jabawocky

It has been a very long time since I looked at piston engine theory and Random Access Memory is at a premium in my alcohol ravaged mind.

I dusted off my piston engine theory texts today and you are correct About BMEP. I have used the incorrect term to describe what was happening. BMEP occurs when friction losses are minimal at peak torque and BFSC is lowest. We can extract more horsepower past this point but it is a diminishing marginal return as a function of increasing RPM. However I stand by my physical understanding of what was happening in the engine. High power settings combined with a coarse prop settings would have increased IMEP and increased the frequency of resonance in combination with the gearbox.

BMEP+FMEP = IMEP

The friction losses in a Rotax would be higher than a direct drive because of the higher RPM and larger change in RPM. The rotax is also driving a water pump impeller. A coarser pitch would also cause a more rapid oscillation in crank RPM as the prop decelerated after the power pulse and the gearing worked to accelerate the crank.

I also rang the guy who pulled the engine down and the even two metallurgists couldn't agree when the failure was initiated. There was evidence of a minor manufacturing fault in the crank but it was deemed that in normal service it wouldn't have caused a failure. What everyone does agree on is that the engine was abused. I respect your opinion on this Jaba but do you know the nodes of resonance on this engine and where they occur? I am sure you can easily work them out but have you? Did the manufacturing fault respond to a particular frequency? If mechanical engineering was perfect science engines would never fail.

Its immoral to operate an engine outside factory limits and we will never know what initiated the failure, but it certainly introduces an element of doubt? Its the same as over stressing an aircraft and not telling people about it,

It is also very poor form to bag the pilots landing, whatever his shortcomings. None of us know how we will react when the time comes and if we will be found wanting. My opinion on the circumstances of this event have not changed.

Jabawocky

29th Jul 2013, 10:25

What everyone does agree on is that the engine was abused. I respect your opinion on this Jaba but do you know the nodes of resonance on this engine and where they occur? I am sure you can easily work them out but have you? Did the manufacturing fault respond to a particular frequency? If mechanical engineering was perfect science engines would never fail.

Ok so now we are getting closer to the mark. No I have not and have no desire to waste my money on doing a torsional analysis of a crankshaft nor can anyone quantify the extent of the severe out of balance prop. Noted by the deceased.

My concern here is the abuse you believe that everyone agrees on is that of the deceased owner, not the previous owner. The significant vibration issues were the problem induced by the deceased as best my memory serves. I could be wrong!

If the abuse as you allege was from pitching the prop to extract maximum speed, how on earth could that have exceeded any manufacturers tolerances. It almost defies logic, and if it was pitched finer, to extract max RPM thus HP (less prop efficiency drops) then that may be considered abuse, however I doubt that Rotax have a crank designed so close to the limits. If they do I will suggest that nobody I know will ever fly behind one again. I bet Rotax run them at 5800 RPM at full load for hundreds of hours in testing. I would be surprised if they have not. But I could be wrong.

The ATSB report said "The appearance and 45 degree angled progression of the crack in the number one connecting rod journal was consistent with fatigue through cyclic torsional loading." So while you may not see anything different here, I wonder how this is most likely to happen? Continuous operation at 5800 RPM for a few hours in a row or by many hours of a severely out of balance prop?

Just because the coroner could not see through this does not mean it is not the most likely cause.

I concede my view of this accident might not be the case, but it stands up to the logic of physics far better than anything in the court room ever did. I will say again, the alleged paperwork and other issues that the seller may have been guilty of had nothing to do with a crank failure. Lets blame Boeing for the SFO crash shall we.

I have nothing more to add. Punters can read all the material if they have access to it and make up their own minds, of course be wary folks of what you read and believe, tomatoes will kill you!

I am quietly confident that Rotax make a very well engineered and robust engine. I have spent maybe 100 hours behind them, and I would say from what I have seen of maintenance they are no less reliable than a Lycoming or CMI engine. That being said, the old technology dinosaur engines are equally or more efficient, and do provide more HP for those who need it.

Remember the fuel debate, 80% of the fuel is used by the fleet section that MUST have an aviation fuel equal or better than 100LL, so an UL low octane can't work. Same goes for HP....the major uses of HP are the big guys, and they cant do it on a 912. They would need 6-8 of them.

So horses for courses :ok:

Oracle1

29th Jul 2013, 11:05

On September 21, 2006, JG had the prop inspected and balanced by Mr McCarthy, a Licensed Aircraft Maintenance Engineer (LAME), who was then the manager of an aircraft maintenance centre at Albion Park. Mr McCarthy explained in detail to the court the procedures he adopted to balance the prop. Extraordinarily, when he removed the weights attached to the prop upon arrival, its balance improved. In his experience this was abnormal. He then proceeded to achieve what he thought the optimum balance, to within a tolerance of 0.2 inches per second.
JG advised Mr McCarthy later that the prop appeared to have been well balanced and that he was more than satisfied with the job.
The evidence revealed the probability that the problems as to vibration were inadvertently attributed to the propeller being out of balance. As it turns out, this does not appear to have been the actual source of the problem. Mr Brian Nicholson, an aviation consultant, now retired, but still a LAME, stated that the adjustments to the prop potentially masked the true source of the vibration, namely, torsional twisting of the crankshaft, which was revealed to be out 15 degrees. Consistently, Mr McCarthy’s evidence that unusually the balance improved when he removed the weights also suggests that the propeller was not the cause of the imbalance.
What is very clear is that throughout the nearly 2 ½ -year period of JG’s ownership of the aircraft, he was diligent in ensuring, and recording, all required servicing, and all necessary maintenance including constant attempts to address any deficiencies. The only suggestions to the contrary were made by Mr Coates and Mr Allen. They were not disinterested, to say the least, and all other evidence allows me to reject their criticisms outright

Does a LAME not know how to balance a prop?

Sounds to me like the crank was already on the way?

The records kept by JG reveal that he had constant problems with the aircraft after purchasing it from Mr Michael Coates on September 1 2004. These problems are corroborated by others, including Mr Coates and his friend and associate Mr Allen.

Initially, JG’s concerns focused on the Woodcomp electrical adjustable aircraft propeller and vibrations that appeared to emanate from it.

The guy flagged straight up he was having problems with the prop and made attempts to fix it, misguided or not, even the LAME didn't pick up the crank might be on the way. He certainly sought expert help.

AND FINALLY the real classic

One could be forgiven for doubting whether any maintenance or servicing was ever performed on the aircraft while owned by Coates. His record keeping was so appalling and to the extent that it existed at all, inaccurate, that we will never know. Very little if any of his two days oral evidence could be accepted other than his own admission as to his deceptive, or fraudulent dealings with RA Aus in relation to the registration of aircraft and use of unregistered aircraft, his ‘re-registering’ of an unregistered plane, his continued use of Czech registration in Australia in contravention of requirements, and his wrongful use of the serial number of an aircraft in Australia, on an aircraft in the USA. He compounded the litany of dishonesty by having prepared the Condition Report in August 2004 required for the sale to JG despite being prohibited from doing so by his pecuniary interest (i.e. ownership) of the aircraft on which the report was compiled, and further, without the qualification required to do so. There is a strong likelihood that records which he did produce to the court were prepared for court production, and also that ‘Logs’ were not contemporaneous but may have been fictionally backdated to ensure a sale. He admitted that much of what was written by him in his Sting newsletters stretched the truth or were ‘sales puffery’ for marketing purposes.
He claims that he set several speed or endurance records in the original Sting, which he then sold to JG. It is not clear whether JG knew of these claims; their significance, if true, is what effect that may have had on the engine, apart from whether he maintained regular if any servicing. It became necessary for Mr Coates to be granted a Certificate pursuant to s 33AA of the Coroners Act 1980 in so far as his evidence was concerned relating to the registration of the aircraft and his participation in the false affixation of the same registration details to another aircraft.

Small paperwork problems eh Jaba?

A few hours at MAX RPM? I would say lots

The teak tough little crank was probably already moving and the owner may have been chasing a balance problem that never sat still because it may have been caused by the terminal injury to the crank. If it hung for another hundred hours its another testament to the german engineers

Jabawocky

29th Jul 2013, 11:46

You are being selective with the facts as presented. What happened with all the matters noted from 2004 through to 2006 which involved many prop issues and parts changed or replaced or whatever. Sourced from suppliers other than the OEM/dealer???

All of which was prior to Mr McCarthy doing work on it? Is it any wonder when McCarthy removed weights the IPS improved? And that is unusual as noted by the LAME. I do assume the LAME knew what he was doing. Prop balancing is a black art, but not hard to do, by the way I never accept anything at 0.2, if it is not under about 0.07 we keep going, but I digress.

So the issues are not about McCarthy at all, it is all the stuff in the year and a half before that. Much of which I question by virtue of who was doing the work, including balancing, which I assume is where the weights (noted by McCarthy) came from.

Maybe the notes I read were far more detailed than those you had access to, but it does not change the fact that the greatest risk to crank failure was REALLY bad prop balance in my view, all of which was under the control of the deceased and prior to the LAME.

Go check the dates and events.

like I said before....I really have nothing to add (despite the words above), I think from what you are telling me that the Rotax is very susceptible to high RPM and or balance beyond what I call acceptable. So I best not fly behind one.

So in the debate of Lyc/CMI or Rotax......I will stick to the LYC/CMI's in future.:ok:

Ultralights

29th Jul 2013, 22:33

in my experience, i have flown 700hrs behind Rotax 912's never had a problem.
similar hours behind Lycomings and Contis,with only carby icing causing a few blips on what would be perfect operations, even 50 in front of a 2 stroke 503 rotax,
only ever had one engine failure. in a jabiru.

Sunfish

30th Jul 2013, 22:11

Typhoon:

I'd just like to point out that auto engines are not near as frail as many here are pointing out.
Many, many manufacturers randomly pull an engine out of production and subject it to extensive, punishing dyno work. Even in the 60's, Chrysler would run production V8's at max rpm/load on dynos to the point of failure or 1000 hours often easily going well over 1000 hours with no failure.
Let's not even start on plain old auto engines which are converted for marine use which run at a constant load and power setting for hours on end.
Certified aircraft engines are great things, they are light, simple and reliable, but they are not even close to being optimised for what they do. They are old designs optimised for what they have to do, but no way are they an example of the perfect solution for the job.
The only reason they are still what they are is certification costs and lack of manufacturing volume to justify new designs.

This is bull****.

1. You still don't understand duty cycle. It is not "running 1000 hours at full throttle".

For an aircraft engine it is:

(a) cold soak on wet aerodrome for one to three weeks.

(b) start engine, warm for ten minutes or less.

(c) Apply full throttle for Five minutes. Then cruise power.

(d) Repeat this cycle of thermal loading for at least Five years, with periods of abuse like subzero starting, high temperatures etc. thrown in.

2. New designs offer no benefit. Because of the limited operating rev range of the propeller and consequentely the engine. All of the new technology stuff in auto engines is to improve fuel economy through reducing volumetric losses or to improve the shape of the power curve by widening the band where efficient combustion is available..

If an aircraft engine was required to have a power band from say 1500 rpm to 5000 rpm you would be right, but it doesn't.

3. The marine variants of automotive engines are derated by between 50% to 66% of their advertised "automotive horsepower, except for the "consumer" outboards whose duty cycle is similar to a car anyway.

Jabawocky you are confused about power curves. It is possible to seriousy bugger an engine. The performance is optimised as a torque/rpm combination

The curves you see are actually advertised torque at maximum power for the specified rpm.

To put that another way, you can strangle the engine, it will run over torqued,, but at less power.

Typhoon650

30th Jul 2013, 23:06

No, your statement is BULL****. I clearly understand duty cycle and have provided two examples of many that show auto engines can easily run at full load for extended periods.
Please cite your references for marine engines being designed for 50-66% of duty cycle, that is bull****.
As for the rest of it, every day auto engines are abused far, far more than any aero engine. Cold soak? Big deal, millions do it daily. Full throttle from dead cold? Again, millions do it. AND they do it with lack of oil changes or any maintenance whatsoever in many cases. Not like a fragile aero engine which will **** itself if you don't change the oil after 100 hours.
Of course, of modern aero engines were liquid cooled, we wouldn't have to worry so much about their "advanced, optimised" design being shock cooled or running at full power after a short taxi and run up....
You clearly do not understand marine engines at all. They are under a constant load, just as an aero engine is. Yes, even outboards.
As I said before, we have what we have because the market doesn't justify expenditure for new technology, nor does the regulatory system.

Jabawocky

30th Jul 2013, 23:26

Sunny, Jabawocky you are confused about power curves. It is possible to seriousy bugger an engine. The performance is optimised as a torque/rpm combination

The curves you see are actually advertised torque at maximum power for the specified rpm.

To put that another way, you can strangle the engine, it will run over torqued,, but at less power.

No confussion, I have been working with Torque v Speed curves all my life. Chuck a prop on the end instead of a load like a hydraulic pump doing a constant torque job, and you have a big fan. The laws of phsics are the same to all things.

The curves you see are actually advertised torque at maximum power for the specified rpm.

Care to explain that in english?

you can strangle the engine, it will run over torqued,, but at less power.
Ahh I don't think so. An engine can only generate so much torque, it can't create more. An elevctric motor can produce more than FLT, simply load it up, the RPM starts falling, and she backs up the Torque V Speed curve quite nicely. We use this to our advantage some times, in fact quite often;) . Of course what does happen is the current draw starts climbing at a rapid rate, effective but not efficient, but who cares.

Combustion engines do not work that way.

You can apply an instantaneous peak torque by suddenly stopping the propellor, such as a "Prop Strike", this has X amount of torque from the engine plus Y amount from the sudden deceleration of the prop (inertia conversion) and bingo the crank sees a torque spike many times the maximum the engine could ever produce.

That is why you bulk strip em :ok:

Oracle1

31st Jul 2013, 07:54

Automotive engines are optimised to operate at constantly changing power settings. Aircraft engines are optimised to operate at a constant power settings . They are designed to do completely different things. Do not make the mistake of thinking the actual structure of aircraft engines are fragile. They are very robust.

This does not excuse the intellectual and engineering laziness and the extortion racket that is american aircraft engine manufacture. Thanks to the explosion of LSA Ultralight and experimental categories the american manufacturers have been dragged kicking and screaming to the table to develop better engine management systems. There is no way a 6cyl direct drive is worth 60,000. When the chinese begin to copy and adapt the direct drives the price will drop significantly. Execute a few parasite lawyers and we could drop the price as well.:D

If you could shove a car engine into an aircraft at low cost everybody would be doing it.

Jabawocky

31st Jul 2013, 08:32

Oracle,

Do you know how much of the say $26K for a Rotax is for the engine and how much is a result of insurance alone?

I wish I could recall the figure, but it is staggering, something like 40%, maybe someone here can shed some light.

What CMI and Lycoming haf to contend with is having civil cases rammed down their throats because pilots kill themselves and passengers from VFR into IMC, or faulty carby's on an engine built 38 years ago and rebuilt once or twice.....and the fault was....Loss of control, or carby ice or both!

Seriously it is STUPID, I had this discussion with Bill Ross, the Manager of Factory services at Continental about 4 months ago. He attended the APS class we were teaching at and his response was one of frustration at the level of stupidity. So is it any wonder.

Fix that problem alone and GA might grow again.

Oracle1

31st Jul 2013, 08:42

I heard a figure that profit from 3 out of 10 helicopters off the production line go towards liability. I am well aware of this issue, my family are all commercial solicitors

as I said,

Execute a few parasite lawyers and we could drop the price as well.

Jabawocky

31st Jul 2013, 10:25

Probably not profit, probably gross income.

I agree 100% with your last sentence. Creamie might not :uhoh:

Sunfish

31st Jul 2013, 20:34

Jaba:

Ahh I don't think so. An engine can only generate so much torque, it can't create more. An elevctric motor can produce more than FLT, simply load it up, the RPM starts falling, and she backs up the Torque V Speed curve quite nicely. We use this to our advantage some times, in fact quite often . Of course what does happen is the current draw starts climbing at a rapid rate, effective but not efficient, but who cares.

Combustion engines do not work that way.

You can apply an instantaneous peak torque by suddenly stopping the propellor, such as a "Prop Strike", this has X amount of torque from the engine plus Y amount from the sudden deceleration of the prop (inertia conversion) and bingo the crank sees a torque spike many times the maximum the engine could ever produce.

That is why you bulk strip em

Agree with some of what you write.Prop strike creates a "torque pulse" (actually a stress wave) that propagates from the propeller through the crankshaft, gets to the other end of the crank and is then reflected back in reverse. This goes on until it dies away or the crank deforms or something else breaks.

I built one of these, that uses the phenomenon of a torsional stress wave, for my engineering masters.

Split-Hopkinson pressure bar - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Split-Hopkinson_pressure_bar)

As for "running over torque" try putting your car in Fifth and let out the clutch and see what happens - you are asking the engine to run in a manner it is not designed to - which is why you have that table in the POH of manifold pressure/rpm combinations - including areas/combiinations to avoid on some engines.

Typhoon, no, its not bull****, marine engines are derated, in some cases there are Four ratings depending on the intended service.

Take a look at the Volvo Penta marine commercial and marine liesure web pages, take the D9 series for example. In pleasure boat form it is rated at 500hp at 2600 rpm. In cat 1 SOLAS form it is rated at 300 hp and 1800 rpm for ultimate reliability in continuous use.

Also look at the D13 which has ratings from 400 to 800 HP!

Diesel inboard - Engine Range : Volvo Penta (http://www.volvopenta.com/VOLVOPENTA/AUSTRALIA/EN-AU/MARINECOMMERCIALENGINES/INBOARD/ENGINE_RANGE/Pages/p_diesel_inboard.aspx)

D6-370 - Engine range : Volvo Penta (http://www.volvopenta.com/VOLVOPENTA/AUSTRALIA/EN-AU/MARINE_LEISURE_ENGINES/C_DIESEL_INBOARD/ENGINERANGE/Pages/d6_370.aspx)

aldee

31st Jul 2013, 21:09

Aussie Bob

1st Aug 2013, 02:25

A Squared

1st Aug 2013, 02:36

Marinised engines are able to produce significantly greater hp per in3 of displacement as compared to land based version of the same engine due the available coolant, oceans full of it !

Sorry, I don't agree. The optimum temperature for a water cooled diesel engine is around 90C. All the diesels I have ever operated have easily managed this or lower on a conventional radiator and fan. Sure the sea makes it easy but in this day and age the optimum radiator/fan combo is also not very difficult to build.

Yeah, that was one of the more ridiculous things posted in this thread. If increasing the horsepower per displacement was simply a matter of better cooling, we'd have bigger radiators. Automotive and truck cooling systems these days have plenty of redundant cooling capacity for all but the most extreme conditions. Don't believe me? Pop the thermostat out of your cooling system and then drive around town for a bit and tell me what your temperature gauge reads. Just the fact that there is a thermostatically controlled valve in the cooling system should tell you something about cooling capacity.

nomorecatering

1st Aug 2013, 07:50

Discussion about spark ignition engines is moot in any case. The legacy engines are a dying breed, diesel is the future.

Continental has bought Thielert, and also has their on version of the SMA engine about to be certificated, the TD300.

Austro is producing diesels for Diamond and I haven't seen any bad reports about them.

Engineered Propulsion Systems is certifying its 4.4 lts Flat 8 engine at 400 hp.

There are also any number of engines in the wings, Delta Hawk for one.

Creampuff

1st Aug 2013, 10:15

I'll bet you a litre of AVGAS that there will continue to be more AVGAS or MOGAS engines in the air than diesels (excluding heavy metal aircraft) 10 years from now.

I'll bottle that litre of AVGAS now, in case I have to pay up in 2023. :ok:

Oracle1

1st Aug 2013, 10:26

Lots of diesels in the pipeline very few certified and even the certified ones (thiealert) having big problems. Deltahawk still trying after more than ten years, still no certification, some 65,000 grand for the experimental version so you can be the guinea pig both financially and bodily. Wanna burn diesel? Get a turbine. The turbine is still the best engine to go flying behind.

Jabawocky

1st Aug 2013, 11:17

Oracle and Creamie are correct.

When the G100UL paperwork is complete, a 100% drop in replacement will be legally available FLEET wide.

Then the piston petrol burners will be given a new life.

Hang in there :ok:

nomorecatering

11th Aug 2013, 02:01

A south African company have come up with an interesting engine, which seems like a scratch build design, not an automotive conversion. 320 hp and weighs 320 lbs.

Adept Airmotive (http://www.adeptairmotive.com)

Shagpile

11th Aug 2013, 02:29

Doesn't have any numbers on the website about claimed extra efficiency...

HarleyD

14th Aug 2013, 11:53

Adept, an engine that i looked at Waterkloof last year is yet another concept, not a certified product, just like the others. The very simple fact is that there is no certified, proven 300hp range diesel in the market place at this time. I hope adept, and a few of the others, get up and provide a real alternative to the huge fleet of IO 540's and520's that are ready for a heavy fuel replacement.

I have seem most of those diesels mentioned here, and a few others over the many years, many running on test stands, ....but.....still waiting fellas.

I was at the Austro factory in Weiner Nuestadt a few weeks ago and they seem like they could kick a goal, but time and millions of dollars will tell.

I saw the prototype c 182 with the SMA fly into Sywell with only 20 hours on it, gutsy, but that engine has at least some history behind it. A bigger 6 cyl version would work but seemingly wont happen.

There is plenty of motivation for a 300 to 350 hp engine, and many in the race, but it is not a simple task and i am still waiting.

Bring it on. About time to shake TCM and Textron up.

HD

27/09

15th Aug 2013, 02:06

I don't see the spark ignition engine going away in the foreseeable future. There's a very large already in service fleet of spark ignition engines. The current demand for new, as in OEM engines, is very small by comparison.

Unless there is a very compelling reason for the existing fleet to fit diesel engines there is only ever going to be a small market for these new engines. Too small in most cases to produce them economically. Retrofitting in most cases will be far less cost effective than continuing with the the old engines.

Diamond have fitted Lycomings to their Twin Star.

Jabawocky

15th Aug 2013, 11:04

It is a romantic notion, and at times due fuel availability it might make sense, but overall, the physics do not allow the concept to take over.

Ultralights

15th Aug 2013, 11:41

Shagpile

15th Aug 2013, 12:57

Roller tappets saving the day! Hooray

27/09

15th Aug 2013, 20:33

the new generation of small capacity petrol vehicle engines are now achieving fuel economy figures near enough to diesel engines, especially now that direct injection has been made to work with petrol.

Is the BSFC on aero engines all that bad?

I like my Lycoming (Or Continental) once its running all it needs to keep going is a supply of good clean avgas. No electrics needed to manage the engine. I've done some longish over water legs and wouldn't want to be flying behind the likes of a Theilert (or avgas equivalent) when the electrical system goes south and the battery goes flat, or the engine management computers throw their toys out of the cot as has happened on some Theilerts.

Sunfish

15th Aug 2013, 21:40

Ultralights:

the new generation of small capacity petrol vehicle engines are now achieving fuel economy figures near enough to diesel engines, especially now that direct injection has been made to work with petrol.

With respect, I think you might need to qualify that statement a little. I'm sure that in an automotive duty cycle you are correct, but in an aviation duty cycle around 55% to 75% continuous power?

As an aside, Monday morning I pick up the Twin turbo V8 diesel replacement for my 18 year old 80 series Landcruiser. I note however that the latest Niccan petrol patrol is about as fuel efficient - by means of turning off a couple of cylinders at cruise - something I don't think you would want to do in an aircraft.

Jabawocky

15th Aug 2013, 22:57

This thread has gone full circle. The BSFCmin of a "conforming aero engine" one that will operate as nature intended is around 0.385-0.395 and that is pretty hard to beat no matter what you do.

In an aero application requiring all the design parameters we need and want to be met, it is pretty hard to get any better.

you can argue turbines are better....they are, but not down where all the GA machines live. There are compromises and the laws of physics do not change just because we think they should. :)

ForkTailedDrKiller

16th Aug 2013, 00:53

the new generation of small capacity petrol vehicle engines are now achieving fuel economy figures near enough to diesel engines, especially now that direct injection has been made to work with petrol.

why hasnt this technology made any headway into aircraft engines? Its fascinating technology!

My 6.0 L V8 Commodore SS uses 99.9+ L/100 km on "take-off":E, but drops back to 4 cylinders when cruising on a flat road and uses 8 L/100 km at 100 km/hr. :ok:

Don't know what my wife's 2.0 L Corolla uses on TO, but it also uses 8 L/100 km at 100 km/hr!

Kinda cool when I think my 1976 Torana 4.3 L V8 used about 25 L/100 km, but I don't think I want computers running my aeroplane engine!

Dr :8

Jabawocky

16th Aug 2013, 05:44

That would have been the 4.2L wouldn't in Forkie :ok:

Maybe the younger Forkie, sans speed traps everywhere would thrash it a bit more than the modern day Forkie ;)

See them coppers are saving you money, emissions and keeping the roads much safer! :rolleyes:

:}

dubbleyew eight

16th Aug 2013, 06:56

most fuel efficient car on the road is a turbo charged 2 cylinder thing in a Fiat 500. small engine flogged for all it is worth. 3.7 litres per hundred km.

OZBUSDRIVER

16th Aug 2013, 08:09

Hey, Apples with Apples!

We are comparing high efficiency engines running at small percentages of power to maintain the legal speed limit. Should we be looking at the same situation for a flying machine? Max range/ max endurance occurs at the best lift drag or just past the fattest part of the power available power required curve...which is nowhere near our normal cruise speed. 75% power continuous in even a stocker 4l Falcon will have you north of the legal speed limit to a point beyond the survivability of your licence and a fuel economy that matches the current government.

For argument, should we look at the idea of planning to a ground speed and conserve the fuel flow?

EDIT to add...basicly, what Sunny said. BSFC to compare.

nomorecatering

16th Aug 2013, 12:48

HarleyD

SAFRAN, the parent company has just launched a 6 cylinder diesel.

SMA?s SR460 engine on the Safran stand (http://lebourget.safran-group.com/news/sma-s-sr460-engine-on-the-safran-stand.html)

Would love to see that one under the cowling of a Piper Matrix.

27/09

16th Aug 2013, 21:20

Jabba

The BSFCmin of a "conforming aero engine" one that will operate as nature intended is around 0.385-0.395 and that is pretty hard to beat no matter what you do.

In an aero application requiring all the design parameters we need and want to be met, it is pretty hard to get any better.

you can argue turbines are better....they are, but not down where all the GA machines live. There are compromises and the laws of physics do not change just because we think they should.

I agree re the laws of physics. You can break the laws of the land and get away with it a lot of the time but you cannot break the laws of physics.

When I asked the question Is the BSFC on aero engines all that bad? I was hoping Ultralights might have responded to prove his/her point.

All this fancy electronic whiz bang gadgetry in a car is mainly there to reduce maintenance/tuning requirements. It doesn't mean it's actually any better at producing maximum efficiency in some cases it doesn't. What it does do is guarantee a known level of efficiency for minimum maintenance effort.

Old simple technology can give very good levels of efficiency with high levels of reliability but requires regular tuning/maintenance.

Jabawocky

16th Aug 2013, 23:33

Yep, and the real focus and benefit is emissions control.

Basically in my car, I fill it up when it needs to be filled. If I give it a bit of stick :suspect: it burns more.

In the plane I want to go a long way and fast, so ignoring the most efficient airspeed, which of course will be much slower, the best compromise is go as fast as I can on the least amount of fuel.

Simply WOT/23-2500 RPM/10-20dF LOP :ok:

The Landmarks to understanding combustion graph is a wonderful tool in teaching people where this all works, when you understand how the various inputs into the entire system work you can pick the best go far or go fast mode, or anywhere in between if that serves the mission purpose.

I really do like the dinosaur engine with manual control of inputs, because even a 25 watter like me can achieve impressive results :ok:

A point in case, I have a friend with a very good auto engine installation in an RV8, one of the few in the world that actually perform, don't run hot etc. guess which is more efficient in a heavier more drag airframe, pound for pound around the county ? Yep you guessed it, the Lycosaurous is. By a sizable margin. And yes he has all the engine control at his finger tips.

He is building up a stock of parts for an IO360 conversion. Not sure why? :confused:

nomorecatering

30th Aug 2013, 04:17

Just an interesting article on engines.

Will we all be flying diesels? - Aircraft Owners and Pilots Association (http://www.aopa.org/News-and-Video/All-News/2013/August/1/Will-we-all-be-flying-diesels.aspx)

Engineered Propulsion Systems vision350 looks promising if the numbers are true. In fact they are astonishing. Compared to a Piper Matrix engine the fuel flows are roughly halved.

Green Car Congress: EPS showcases lightweight Vision 350 diesel aircraft engine at EAA AirVenture (http://www.greencarcongress.com/2013/08/eps-20130804.html)

Vision350 8 cylinder v Lycoming TIO-540AE2A

Eps (http://bioage.typepad.com/.a/6a00d8341c4fbe53ef019104933a77970c-popup)

43Inches

30th Aug 2013, 05:52

From the article they are aiming for an installed weight of under 300kg assuming it will be around that figure. How does that compare with an installed TIO-540 for example on a Chieftain. I know the dry engine weight is around 200kg, does that include ignition equipment, turbo, manifolds and induction etc...

porch monkey

30th Aug 2013, 06:53

Don't think so. Bare engine.

Jabawocky

30th Aug 2013, 11:21

The Matrix engine is 7.3:1 comp ratio so at 75% power LOP it is 19.5GPH not 21.5GPH.

If you are going to compare a diesel to a gas engine it has to be LOP, not ROP.

Lets compare a TNIO550, at the same 263HP, 17.65GPH.

Gap is closing.

Now lets look at this little gem, Plane that made emergency landing Wednesday was experimental Cessna | Wichita Eagle (http://www.kansas.com/2013/08/23/2960058/plane-that-made-emergency-landing.html)

So what can cause this? Most likely a hose clamp in the turbo to inlet port. If this happens on your IO540 or 550 300HP engine or even on a Turbo engine, what do you get? You get ambient MP and you still produce some reasonable HP.

These Diesels you get about the same as a very tired Rotax 582 two stroke. 50HP. :eek:

You will not get me flying one of these any time soon. :uhoh:

Weight, 250kg - 270kg for the Lycomings, so the Diesel all up with all the gear is going to be nothing like 300kg. That is like asking a woman her weight!

The laws of physics apply equally to all things.