Kitplanes auto engine roundup...sad!

Austro has had a number of teething issues since switching to their own manufacturing of the engines.
For example, they had an issue with the pistons for example, the new pistons were made to spec by a small firm exactly meeting the specs from MB. Well, the pistons MB had been using actually did not match spec :D the manufacturing process for high volume used by the MB supplier actually produced pistons which were always at the bottom range of the spec or slightly smaller (I think it was 1/1000 of a mm, or some insanely small amount).
Anyways, it can be done. It just takes time and money to make it happen.

Oh, the CMI small diesel engines (was Thielert) where actually MB engine designs which were converted from an iron block to aluminum.

Tim
 
A quick remark about above comments re modern automotive engine reliability and recent rash of recalls, in terms of comparison to aircraft piton engines.

Modern mass produced car engines are designed from the get-go to be cheap to produce in terms of materials, manufacturing process, etc, but also to a considerable mission of emissions and MPG. As such, we see so many big cars being propellled by small displacement turbo charged with some engines having a sprayed in cylinder wall rather than steel sleeve or precision honed. The pressure to make such an engine to check so many boxes has recently produced new tech and adage of ‘time will tell’ is manifesting in short comings that will eventually be addressed. This is expensive for manufacturers….i actually got a spanking new engine at 90k miles in a Subaru under warranty (unfortunately daughter rear ended a Volvo and car was deemed a complete loss only months later…. No one hurt but I felt cheated ,,,,yet I digress). The new better piston ring design failure resulted in a recall.

Point is I continue to see many auto conversions doing same as auto industry in using low displacement engines with turbos to pump more power to prop…. It sounds like ideal solution in terms of thrust to weight , but there’s a number of pit falls when engine is rotating a constant loaded prop producing very dynamic asymmetric shaft loading and mostly a hard straight/direct drive….. without getting into boring engineering mumbo jumbo, I see many auto conversions using same philosophy as car manufacturers in that using small displacement engine solutions, but remember a car has a smart transmission that is computer controlled to isolate much of the harsh loads, and cars typically only use 20-30% of rated hp once up to speed due to such things as lower drag coefficients such as smaller drag profiles (think of parasite drag caused by just wings) not to mention induced drag coefficients…. Imagine your plane towing a parachute that constantly expands and contracts (and even holding short, the prop is producing thrust, thus load, as it can’t be decoupled from prop load ….sort of like maintaining 1500 rpm with the parking brake on in a car).

I use the example of imaging you are constantly towing a heavy boat on a trailer up hill, some steeper than others. The turbo will induce enough potential energy into cylinders for engine to make its max rated power, but the lifters, rods and connected components will be stressed to limits for longer periods of time that will likely be beyond design limits…..consider the stress bending of the crank shaft (imagine a straight line drawn down the shaft, that line will be slightly twisted and varying under load, so the front and back of shaft don’t line up, but then do line up at low rpm but than twist yet again with power; or with combustion event the same shaft misalignment pulses further stressing it out ) which will dissipate its deformities to affect other components precession fit such as bearing surfaces and so on. Other compounding factors as increased oil temps which decrease oil lubricity (how slippery it is) and more extreme heat cycles don’t help (although liquid cooling helps mitigate this compared to air cooled).

I live in the Rockies and constantly hear of people complaining their truck engines fail at low miles , almost all are avid campers regularly towing titanic and heavy RVs up the steep gradients, and yes, they are below the trucks towing capacity limits. This stress is cumulative, and experienced campers here know to buy a truck with more towing capacity than they technically need…

Same with a plane, if you need 160hp and install a car engine that’s 160 hp rated in say a VW Jetta, you are inside the hp limit but really outside the design limits and will constantly be playing test pilot. Of course there are methods to mitigate risk such as routine tear downs or replace the block every 300-500 hours as race cars do after each or evert 2-3 races, but may as well just installed a certified o320 as most proposition advantages are erased.

We got criticism in using a v8 for the c172 program from several engineering professionals with prestigious degrees from such institutes as the university of YouTube and internet U telling us we used to big an engine for only a 220hp application. Again, for the reasons above as well as we wanted the same block to fit different aircraft and hp requirements, and wanted a high TBO to further reduce costs and greater reliability as only using 40-50% of its design limit..
So our mission was a bit different than a hobby exp kit plane.

So to more directly focus on OP, using a small low displacement engine on a bird that only needs its car rated hp brings issues, and likely the reason why so few conversions exist , or have gone under, in the 120-200hp range and typical weight limits . As flying continues to get more expensive, I expect we will see other engine options as engines are the most expensive element, but it’s hard for upstarts to get any traction in this space as pilots are correctly weary of new tech, especially critical components, so new companies have to have the resources to stay in the game until it’s wider acceptance and reach profitability. Even more difficult for a new certified solution.
 
StraightnLevel said:
No. Entry level means first airplane purchase.
Click to expand...
People are buying SR22s as their first plane... not entry level by any means.
Cap'n Jack said:
No, that’s not true. Is is based on a BMW engine, but it isn’t a BMW engine.

Austro Engine E4 - Wikipedia

en.wikipedia.org en.wikipedia.org
Click to expand...
your wiki page is full of dead links that go nowhere.... can't claim authoritative source when all the sources are 404 not found.

The internet archive is also non-authoritative as material isn't available to verify. Just because you find a google link doesn't mean its an answer to anything.

This is interesting: The TCDS lists -

Austro Engine
E4 series engines

Manufacturer
Austro Engine GmbH
POA AT.21G.0010
Wuhu Diamond Aeroengine Co. LTD
Xinwu Economic Zone, Wuhu Country
Anhui Province -– China
POA PC0047E-HD

"
Back around 2006-2009 Diamond (actually the Dries family that owned Diamond back then) invested around $50m to start Austro Engine and certify the AE300 engine. They wisely leveraged as much proven Mercedes-Benz auto engine technology as possible by purchasing a large number of OM640 car engines directly from Mercedes -- engines that Austro put into storage.

Every time they needed to build a new aircraft engine, Austro went into their "back room" to get an OM640 engine, stripped off the Mercedes accessories; added a gearbox, Bosch ECUs, and other aircraft accessories; and created an AE300 or AE330. They didn't need to take apart the OM640 engine core, including the cast-iron block.

Now with more than a thousand Austro engines flying, Austro is running out of original OM640 Mercedes car engines. Mercedes 4-cylinder car diesels are now 2+ generations newer, so Mercedes stopped producing OM640 engines many years ago.

Austro cannot change the design of the AE300/330 without very expensive re-certification of the engines (and Diamond would need to re-certify its aircraft), so it's highly unlikely that Austro would start producing a different engine based on newer-generation Mercedes engines, even if based on a lighter aluminum block.

The logical step is for Austro to start producing its own OM640 engine cores. I'm guessing they can utilize many of the same component parts suppliers that originally supplied Mercedes-Benz, as well as outsourcing core engine assembly."
 
StraightnLevel said:
Sure they do, BUT, auto engines aren't running anywhere near the load factor of airplanes. The driveline has multiple dampers that don't exist on airplanes - heavier flywheel, torque converter, shock mounts on engine, transmission, differential, u-joints on the driveshaft (or CVs), and finally the tires themselves are dampers that reduce the mechanical effect of jerk on the various components. Unless you're on a racetrack or the autobahn you're probably nowhere near the peak power output of an auto engine, while the airplane runs right at peak all day every day.

As an aside, I question why anyone would expect an automotive engine to have higher reliability and/or life than an airplane engine. At 70 mph, 2,000 hours is 140,000 miles. If you drive any car 140,000 miles on the highway, holding it in a lower gear so that it stays just below redline, what do you expect from it? Is it going to tolerate that usage? What do you think the bearings and valves are going to look like?
Similarly, I'm not sure why a 2,000 hour life on Lycosaurus fan engines is seen as problematic. Again, what do you expect from a reciprocating engine?
Click to expand...
I expect it not to self-destruct from corrosion from not being run. Which means using a different oil. Which means removing the lead from the fuel, for a start.
Electronic ignition and fuel injection, with knock sensors and four or six channels to fuel each cylinder individually, ain't rocket science (though, haven't spent 20 years in turbofan cert, it's not likely to pay off for certified engines. But experimental exists, and others will pay you to beta test your stuff.)
I'm extremely familiar with destructive torsional vibration, BTW. Folks using a table in a drive component catalog will often be disappointed at the life the get, unless they 3x the recommended size.
But I'm ancient, and will likely not live to see any revolution in cheap flying. In fact, I don't think it will ever happen.
 
Kenny Phillips said:
I expect it not to self-destruct from corrosion from not being run. Which means using a different oil. Which means removing the lead from the fuel, for a start.
Click to expand...
No argument, but that's not a fault of the engine design.

Kenny Phillips said:
Electronic ignition and fuel injection, with knock sensors and four or six channels to fuel each cylinder individually, ain't rocket science
Click to expand...
True, though there is a downside to electronic ignitions. Magnetos keep firing when the chassis electrical system stops (for any of a number of reasons). Let's be clear, though, that FADEC already is in production. The fact that most legacy 6-pack spam cans don't have it isn't a regulatory issue as much as it is an issue of demand and value for the $$$. If 10,000 of the existing Bonanza or Archer owners told a supplier that they would buy it, it would be in those planes.
 
StraightnLevel said:
First purchase is the definition of entry level. In any case, the new planes with full engine time remaining aren't relevant to the post you're responding to.
Click to expand...
lul whut?

entry-level
adjective [ before noun ]

used to describe a product that is cheaper or simpler than other similar products, and therefore suitable for someone who has not used or bought one before:
an entry-level model/machine/PC

You do you... if you think a $1.3MM airplane is entry level then there is nothing I can say other than LOL WUT?

A Bentayga is a persons first car purchase... thats an entry level car for a 16 year old on a learners permit? AHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA

Wow. Just wow.

I'm done with this particular off topic detour. lol entry level.
 
StraightnLevel said:
True, though there is a downside to electronic ignitions. Magnetos keep firing when the chassis electrical system stops (for any of a number of reasons).
Click to expand...
A battery will happily fire spark plugs for a long time (depending on load). Its not that EI is less reliable, its that the parameters of the situation has changed.

Consider this: you lose your alternator on a lycosaur. Your electronics run off battery for a while then die. Yes, your engine is still running but you might, depending on your personal minimums still consider no comms and loss of all electrical items not a big deal.... but your EFIS, GPS, transponder, radio, position lights etc all all going to go offline no matter what your mags do.

Now you're in a EI aircraft and lose your alternator. Everything is still going to die, but you engine will still run. You might have to shed some electrical systems to preserve battery but you were most likely going to do that anyway and also land as soon as possible, because in BOTH scenarios you have no real idea what is wrong/happening.

A magneto or EI doesn't change the outcome differently. You're gonna turn stuff off/lose stuff eventually. But what an EI does do is make flying cheaper (no repetitive rebuilds) and improves performance (variable timing, hotter spark, no points or condenser, no gears at all)

I can already hear all you high flying devil dogs claiming that you don't need EIFS, radios or GPS or lights... but you're telling me you have a paper chart and that you don't need fuel gauges? Sure you could continue into controlled airspace and try and use the light gun signals... but that's retarded. You lose electrical power you land while you still have a completely functional aircraft because you have no idea what will break next on your already broken airplane. In both scenarios mags and EI allow that to happen.
 
@pfarber

You are very much out of date on the Austros. If you want to pontificate about them, join https://diamondaviators.net/ and you can learn a fair amount.
Austro ran out of MB cores a few years ago. The recent ADs and multiple SBs have largely been due to Austro using the exact specifications from MB to order cases/parts from low volume production houses. The low volume manufacturing techniques often had had side effects that have caused a number of issues.

Note: I am an infrequent mod over there.

Tim
 
pfarber said:
your wiki page is full of dead links that go nowhere.... can't claim authoritative source when all the sources are 404 not found.

The internet archive is also non-authoritative as material isn't available to verify. Just because you find a google link doesn't mean its an answer to anything.
Click to expand...
Welcome to the internet. Stuff comes and goes. The links were valid at one time and were almost certainly checked sometime on Wikipedia after the article was posted. I cite four web pages in the link below (ref 6-9); the journal editors and peer reviewers checked the links prior to publication. Note that the access date is listed. Links that die are the digital equivalent of books and journals that become out-of-press and become difficult to impossible to find; if I happen to have such a book and cite it for something, other people wouldn't be easily to verify the information. There are any number of scientific journals that went out of print before they could be digitized and are difficult to find at best. That never made papers that cite those articles invalid. Web pages may still be valid links but may have different information than the time they were cited.

In addition, you seem to have ignored this posting:
asicer said:
FTFY.

Oh, and BTW. https://web.archive.org/web/2025062...austro-moves-to-building-its-own-core-engine/
Click to expand...
If you were commenting on this, you should have quoted it as I have to avoid confusion. This may what you were responding to with the "internet archive" comment. Note that AI will scrape these archives as well as incorrect data to answer a question.


pfarber said:
Every time they needed to build a new aircraft engine, Austro went into their "back room" to get an OM640 engine, stripped off the Mercedes accessories; added a gearbox, Bosch ECUs, and other aircraft accessories; and created an AE300 or AE330. They didn't need to take apart the OM640 engine core, including the cast-iron block.
Click to expand...
The quoted post above renders the statement below false:
pfarber said:
Diamond uses an off the shelf BMW engine,
Click to expand...
1) It's not a BMW engine
2) It's not off-the-shelf as it is modified by stripping off accessories, adding aircraft accessories, a gear box, and a different ECU. "Off-the-shelf" means no modifications or changes needed.
 
Last edited:
pfarber said:
The internet archive is also non-authoritative as material isn't available to verify. Just because you find a google link doesn't mean its an answer to anything.
Click to expand...
You want the original instead of the archive? Well, here you go: https://avweb.com/news/austro-moves-to-building-its-own-core-engine/

Sheesh. If you wanted the original instead of the archive, it wasn't that hard to figure out from the URL. I mean it's a simple concatenation of https + web.archive.org/web/ + <date> + / + <link>
"https://web.archive.org/web/20250621225422/https://avweb.com/news/austro-moves-to-building-its-own-core-engine/"
 
Cap'n Jack said:
It's not off-the-shelf as it is modified by stripping off accessories, adding aircraft accessories, a gear box, and a different ECU. "Off-the-shelf" means no modifications or changes needed.
Click to expand...
The litterally start with a crate engine. ARe you that blindsided by your effort to try and be the smartestest person in the room?

They took some parts off... so its not a BMW engine anymore? HAHAHAHAHAHAHAHAHAHAHAHAHAHAHHA only the entire rotating assembly, block, water pump, etc etc etc

Well by the smartestest person in the rooms definition NO CAR MOTOR HAS EVER BEEN USED IN AN AIRPLANE because one you take off the exhaust header, its a COMPLETELY DIFFERENT MOTOR HAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAH
 
pfarber said:
They took some parts off... so its not a BMW engine anymore? HAHAHAHAHAHAHAHAHAHAHAHAHAHAHHA only the entire rotating assembly, block, water pump, etc etc etc
Click to expand...
You mean the engine that never was a BMW engine? They source from Mercedes.
I'll just use one HAHA.
 
pfarber said:
The litterally start with a crate engine. ARe you that blindsided by your effort to try and be the smartestest person in the room?

They took some parts off... so its not a BMW engine anymore? HAHAHAHAHAHAHAHAHAHAHAHAHAHAHHA only the entire rotating assembly, block, water pump, etc etc etc

<snip>
Click to expand...
It never was a BMW engine, although I'm willing to look at a citation that indicates otherwise.

This claims the Mercedes OM640 was produced from 2004 through 2012:
mymotorlist.com

Engine specifications for Mercedes OM640, characteristics, oil, performance

The Mercedes OM640 or A-Class 2.0 CDI engine was produced from 2004 to 2012 and was installed only on the second generation of the A-class and the similar B-class compact van. This power unit essentially replaced the popular OM668 diesel engine with a volume of 1.7 liters. The diesel R4-family...
mymotorlist.com
That makes me curious how Diamond/Austro uses an "off-the-shelf" engine anymore.

Although the source is another forum, devoted to Diamond aircraft, the information above makes it likely that the quoted material below is true- an engine core is hardly a drop-in engine.
Once Mercedes stopped producing the OM640 engine, Austro began building the engine core itself. Unfortunately, these new engines suffered from a series of defects, resulting in a series of nine Service Bulletins and seven Mandatory Service Bulletins (and related Airworthiness Directives).
Click to expand...
 
You must log in or register to reply here.
Back
Top