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Another Diesel engine

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Another Diesel engine

Old 8th Jun 2012, 12:12
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Another Diesel engine

Engineered Propulsion Systems of Wisconsin are working on a V8 turbo-diesel, 4.4l displacement, 350bhp, liquid cooled with reduction gear.

The first prototype was just assembled and test-run on the bench. I wonder what is new about this engine and what makes the company believe in it.
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Old 8th Jun 2012, 12:48
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I wonder what is new about this engine and what makes the company believe in it.
The new thing about it is it's horsepower class. There are currently no Diesel/Jet-A1 aero engines in that range that I am aware of.
And they are eagerly awaited for retrofitting piston twins (like C421, Piper Navajo, Beech Duke) and larger singles (like Malibu or C210) of which thousands exist. With the Avgas prices going through the roof (recently I saw Avgas in Italy for 3.8 Euros/litre!) and availability getting more and more doubtful, there is a big market for such an engine!

Last edited by what next; 8th Jun 2012 at 12:50.
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Old 8th Jun 2012, 13:36
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There are currently no Diesel/Jet-A1 aero engines in that range that I am aware of.
The Austro Engine / Steyr 6-cylinder in-line engine should be much closer to certification and with Diamond and the experience with the AE300 behind this, I would give them a much higher chance to succeed in the conventional engine field. While the AE300 is based on a Mercedes car engine with questionable end of life, the AE500 should be able to address that concern.

The SMA/Continental is rated at 230bhp and I would expect them to come up with a 6-cylinder design long time before that new venture even starts test flying their design.

If I was to construct a new aero diesel that is not based on an existing engine, I would neither use a V-type engine, nor liquid cooling nor a reduction gear nor 4-stroke...

With Thielert/Austro on the conventional car side, SMA with a 4-stroke aero design and Deltahawk on a novel 2-stroke concept, it doesn't look like an attractive market for a new venture.
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Old 8th Jun 2012, 13:37
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Wonderful. Let's wait for certification - as experience tells us, it's the stage killing a lot of potentially good and useful products.
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Old 8th Jun 2012, 14:12
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Hello!

If I was to construct a new aero diesel that is not based on an existing engine, I would neither use a V-type engine, nor liquid cooling nor a reduction gear nor 4-stroke...
I have flown a lot on the C421 and C404 and this is really what you want/need in that kind of aircraft! For passenger comfort, a geared engine is second best to a jet. Also in terms of efficiency, a large-diamter, slowly rotating propeller is much better. In all my time on these aircraft, I have never had any trouble with the reduction gears!

As for the liquid cooling, the lack thereof is one of the largest handicaps of the pressurised twins. You have to descend very early and very carefully in order to avoid shock-cooling of the air cooled engines. A very uneconomic way to operate this kind of aircraft, as it really should be flown as high as possible for as long as possible in order to take advantage of it's capabilities.

Four-stroke again is a tribute to noise requirements that are difficult to meet with such large engines otherwise.

And as for the V-layout, I can see nothing wrong with that either.

I think, this engine will be capable of something like 500 to 600 hp when fully developed and might even appeal as a retrofit for some turbine powered aircraft like the King Air 90.

I wish them luck!

Regards
Max

NB: Many years ago, when I was still operating 421s, there was a similar development from Orenda, but not diesel powered. We really considered fitting those engines to one of our 421 with high time engines, for the benefit of liquid cooling alone! But they never made it to certification.
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Old 9th Jun 2012, 05:26
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I am really rather surprised no one has done anything with the VW Tuareg V10 diesel. Twin turbo, 320hp, water cooled and all aluminium except the bearing blocks.

I haven't been able to find out much about it but I reckon if I was looking for a 200 to 250 hp diesel this is where I'd start. De-rated it might not even need a reduction gear.

Possibly the smaller size of the pots allows light construction of the heads. Personally I think there are an awful lot of moving parts in a V10 four stroke and I like the idea of the Junkers diesel but the VW is available.
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Old 9th Jun 2012, 09:53
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This subject comes up regularly.

What "nobody" knows is how long a particular car engine would last when running at 100% power for 10-20 minutes solid (climb, turbocharged) and then run for hours at say 75% power.

These duty cycles are an order of magnitude harder than anything that happens in a car. At 100% power, your life expectancy on the road would be measured in minutes if not seconds

The average "quick" car (say 2000cc) can do about 130mph and at 85mph (UK motorway driving) is running at about 30-40% power.

Even rally cars can trash their engines in a few races, and that is still a much lower duty cycle than an aero engine.

For all their niggling faults and thermal management issues, the old Lycos have a decades-proven ability to run at 65%-75% power for ~ 2000 hours. Nobody has TMK put a dozen car engines on dynos and run them like that.

Even initial engine certification doesn't involve 2k hrs straight; I have forgotten the regime (an engine shop that does that sort of work explained it to me) but it is way short of 2k hrs' bench run.

Last edited by peterh337; 9th Jun 2012 at 09:54.
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Old 9th Jun 2012, 10:16
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Peter I wish UK motorway speeds were 85mph !
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Old 9th Jun 2012, 10:23
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This subject comes up regularly.
And your response is the typical objection :-)

When looking at the Thielert and Austro Engine, I find it quite remarkable that those engines are car designs and that the modifications done especially by Thielert make the engine lighter, not heavier/sturdier for operating under a high power regime. And yet they turn out to be rather reliable (even Thielert does do well when looking at the numbers).

The major issue appears to be the power transmission. A gearbox is required for reduction and even if you didn't require it, the high torque of a turbocharged diesel requires some sort of clutch/torsion bar. Thielert got it wrong, Austro seems to have done a better job at a significant weight penalty.
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Old 9th Jun 2012, 10:39
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. At 100% power, your life expectancy on the road would be measured in minutes if not seconds
Quite far from it. Over here we don't have a speed limit and there are still ways where you can drive at max power for considerable amounts of time. Not hours nonstop of course, but rather run it for half an hour at max, then brake down to low speed (120/140km/h) and then accelerate back to top speed again. This is actually quite demanding on an engine, lots of power changes and due to constant reaccelerating quite often full power demands.

However sadly many if not most manufacturers have a buildin speed limit, most of the time measly 250 km/h, some a tad higher (my last car had 270 km/h). Sadly at that speed the engine won't produce max power, only around 65 to 85% depending on size. Of course that doesn't apply to those small cars some like to drive. Modern car engines engines are pretty steadfast, in fact most diesel engines are used as the core in small powergenerators (Blockheizkraftwerk in german) that are used to power and heat a home or several homes. In those they have to run permanently for at least 10 years without major problems.
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Old 9th Jun 2012, 13:40
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Sure, but it depends on the details.

For example my IO540-C4 is rated at 250HP. This is with 8.5:1 pistons. Variants of it do 350HP, I believe, with I think 10.5:1 pistons and a (only marginally) thicker crankshaft which is accomodated by fitting thinner bearing shells

The 350HP engine has a very poor reliability record however.

The 250HP version seems to be OK, though turbonormalised TIO540 versions rarely if ever make TBO without a top overhaul.

So it is a spectrum... where on that spectrum do you want to be? If you are flying a PA46...

achimha

I have never owned a DA40 or 42 diesel but my observations of the scene suggest that, yes, while we rarely see conrods sticking out of the side of the cowling (car engines really are built well in terms of pure structural strength margins, because weight of the moving parts is a non-issue) we do get almost everything else around it packing up.

Diamond have had ECU problems; not usually resulting in an in-flight engine stoppage but resulting in a landing followed by a fire engine - a regular sight at certain FTO locations. That kind of thing is sure going to put a damper on using the plane for a remotely serious trip. You would need balls of steel to do something like this in a DA40TDi.

They have also had cooling system problems. Diamond claim these were mostly confined to the DA40; Thielert claim in turn that Diamond bodged the DA40 cooling system against Thielert's instructions, and since the bodges were not transferred to the DA42, it did not have those issues. I don't know...

And it goes on, all the way down to crap plating on engine fittings which force the replacement of a lot of bits at the Annual, due to corrosion. I know some people involved in Diamond maintenance.

I am sure aero diesels will be considered "proven" one day but it is too early for me

Don't get me wrong - with the avgas availability matrix in Europe, I would install a good diesel (or any other avtur burner) tomorrow.

Last edited by peterh337; 9th Jun 2012 at 13:42.
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Old 9th Jun 2012, 15:51
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@ChrisVJ

The VW V10 Diesel has a very bad reputation - there were numerous issues with this engine and imho a lot of unsatisfied customers regarding its reliability. Have a look at the used car prices in the SUV segment with larger diesel engines - the V10 really stands out...

Kind regards,
Peter
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Old 9th Jun 2012, 16:40
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You would need balls of steel to do something like this in a DA40TDi.
What, you mean something like this Peter?



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Old 9th Jun 2012, 16:59
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Originally Posted by peterh337
You would need balls of steel to do something like this in a DA40TDi.
If you're referring to the over-water part - it's not that extensive and Adriatic Sea is full of ships so if the ditching part goes well, there shouldn't be any prolonged waiting for rescue. You always have the ability to select a route over land (which would be longer in this case, I agree), if you're not satisfied with the risks of flying over sea.

Regarding the DA40D - I fly one which is kept very well - maintenance-wise and I'm happy to fly at night / over sea. Many Thielert problems (including the infamous DA42 dual engine failure/feathering) were due to fact that pilots operated ECU controlled engines like they did the old O-320. There was even one ditching (I think in Belgium) where pilot set the cruise power at 45% and was unable to maintain altitude (go figure, DA40D isn't exactly what you would call an overpowered aircraft). If the engine is well-maintained and operated as per Diamond's recommendations, it should have more or less the same reliability - of course, you still have a single engine. And many DA40D (all which are equipped for IFR flying) have additional 12V/12Ah battery, which supplies the ECU B in case both alternator and main battery die - and this backup battery is tested for charge (must be at least 70%) before each takeoff and is also tested for voltage at every 100h inspection and replaced every 2 years.
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Old 9th Jun 2012, 17:24
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The DA40 ditching in the North Sea, off Belgium, was an insurance scam, 'friends' with scubadiving gear in a Zodiac were near the location of the ditching. How about that for coincidences? The memory in the ECU permitted the puzzle to be solved. Power set was too low to sustain flight.
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Old 9th Jun 2012, 17:56
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Diesels

Numerous tests are carried out by all manufacturers of both stationery and "moving" engines.As a qualified person I can say with certainty that the average diesel or petrol engine would have absolutely no problem running at WOT for hours as long as it was properly cooled and was being held inside the parameters laid down by the engine builders with regard to safe RPM at max power.35-40% at cruise is easy going;In fact,engines prefer to run at various loads from low speed to full power and prefer to run in extended cycles which reduces wear.A typical diesel will have a max operating limit and a continuous limit.Generators run thousand and thousands of hours without shutting down--or just for an oil change.
I seem to recall that someone in the US is fitting a Corvette V8 to a light aircraft.
Someone mentioned that the VW V10 diesel has been a bit unreliable and it has been so;The gas version is fine.
Interesting discussion this-----I actually have a diesel in one of my Yachts which has run 13,000 hrs with ONLY oil & filter changes at max continuous revs---not even injectors or pump.Had this diesel been installed in a truck travelling at 100 km/h it would have covered an awesome amount of ground......Gasoline engines on the other hand do not last nearly as long but are seldom subject to catastophic failure-----they will just start using oil or maybe burn a valve.Engines have come a long way......
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Old 9th Jun 2012, 18:29
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I am sure aero diesels will be considered "proven" one day but it is too early for me
Well, not so sure about that from the technical reliability point of view. Diamond do have a good safety record and a lot has happened since the first Thielert engines went into service. I haven't heard much at all about issues with the Austro Engine. I have heard a lot about bad cylinders, crankshafts, camshafts, valves, etc. from Lycoming and Continental. I have at one point considered a Cessna P210 (pressurized) but after having found out how easy it is to cook the engine, I realized that one can not trust the previous owner of such an airplane.

The main reason I don't have a diesel aeroplane is because there isn't any that would fit my needs. The Thielert and AE300 currently address the entry level market with 135-165 bhp (180 in the DA52 prototype). If I was considering buying a new C172, I would certainly get something with a diesel instead.

Airplanes like the 182RG or TB20 which give you long range, high altitude and good speeds are no longer in production and there is currently no diesel engine that can deliver 250bhp. Once Diamond get to certify their 6 cylinder diesel and start shipping the DA50/DA52, things might change. It would be great if Cessna restarted the C210 but word is that they wouldn't even consider getting back into the retractable gear business.
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Old 9th Jun 2012, 18:34
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I actually have a diesel in one of my Yachts which has run 13,000 hrs with ONLY oil & filter changes at max continuous revs---not even injectors or pump
I have a friend with yachts (much better than having one yourself) and in his latest and greatest he went for the latest and greatest in engine technology. Two MAN common rail turbo diesels, awesome power. Usually one drives yachts in the Med and if people sell you fuel that is half horse piss half some kind of mineral oil, you get into trouble with such an engine. So another case where modern technology bites the adopter because of bad circumstances. Like with the aero diesels and their ECUs...
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Old 9th Jun 2012, 19:01
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Katamarino - I knew you would be in here sooner or later

achimha
Diamond do have a good safety record and a lot has happened since the first Thielert engines went into service.
What concerns me with stats like that is that it seems obvious from simple observation of the GA scene that there is a big skew in ownership towards flight training (FTO) ownership, and their mission profile is short flights, mostly over land.

FTOs have a strong business motive to suppress reports of problems. It is only if you know somebody in maintenance (as I do) that you discover the extent of it. I know of FTOs who have boasted of a superb relationship with Diamond, when in fact they had more than 1/2 of their fleet grounded, and a very difficult relationship with Diamond. It's business; expect no less, nobody gets the queen's award for enterprise for shafting their business, but it does skew the stats

I know personally just 2 DA42 private owners and both of them are extremely unhappy with the constant hassle the aircraft has given them. Neither would trust the factory (or Mr D specifically) as far as they can throw them. Neither is going to post their dirty washing on an open forum, not least because it would destroy the MV if they wanted to sell. I know of several private owners (of other types) who have carefully concealed severe long term issues, prior to a sale. No; I don't think it is nice...

Whereas the old engines have a massively wide ownership / mission profile, worldwide. You cannot hide anything there. Since the internet was invented, all of Lyco/Conti's dirty washing has been in the open.

I haven't heard much at all about issues with the Austro Engine.
I really hope this is a new phase, but only time (and experience over a more broad mission profile) will tell.

I have heard a lot about bad cylinders, crankshafts, camshafts, valves, etc. from Lycoming and Continental.
Sure - see reason above. The fleet is, what, 100x or 1000x bigger.

I have at one point considered a Cessna P210 (pressurized) but after having found out how easy it is to cook the engine,
Only by thermal mismanagement, supposedly. But probably easy to do, because with pressurisation you fly high and you then want to come down quick, but you can't...

Admittedly PA46 owners say the same, but perhaps the twin turbo 300HP+ installations do push those engines too far.

I could buy a TB21GT today if I wanted to. Or a PA46. I choose not to, largely because I quite enjoy a currently trouble-free aircraft which does most of my mission profile adequately.

Airplanes like the 182RG or TB20 which give you long range, high altitude and good speeds are no longer in production and there is currently no diesel engine that can deliver 250bhp. Once Diamond get to certify their 6 cylinder diesel and start shipping the DA50/DA52, things might change.
I think the retrofit market for private-owner aircraft is dead and buried, with the duty on non-commercial avtur use. It made very little sense beforehand.
It would be great if Cessna restarted the C210 but word is that they wouldn't even consider getting back into the retractable gear business.
There is nothing difficult about retractable gear. Socata have not had any remotely significant issues with their simple design. RG bites you if you don't grease it for 10 years at a time (as many people do) or lube it with "WD40" once a year (as I think quite a lot of people get from maintenance firms).

My guess is that Cessna would not restart those designs because they are so old. Cessna sell the 182 because it fits an important mission profile (utility, short field capability). A 210 has a much more specific appeal, for demanding private owners, but they have other options today.
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Old 9th Jun 2012, 19:37
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Looking at the mass of the engines involved, I think the VAG V10 diesel weighs in at 258kg/570lb for 300-odd HP. Lycomings are roughly 175kg/400lb for 250HP, 225kg/500lb for 300HP and 250kg/550lb for 350HP.

I notice there is a new BMW 3-litre diesel with 381HP that's c.180kg. If you derated that to 250HP (65% of max), which it develops at 2,300RPM, you'd probably be able to lose at least one of the three turbos and save more weight. At that RPM, it'd be ideal for a direct drive large prop...
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