Aero or Auto Engine??

[flyboy007]

Just wondering what the general opinion is on the subject of Auto/Car engines in homebuilt aeroplanes? Seems there are some pros and cons to both arguements as always; Weight saving, fuel economy, reduced maint costs etc versus the old trusted IO540, lack of need for reductions etc etc. Thoughts??

[OpsNormal]

I guess it all comes down to how deep your pockets are.... and how much space you have under the cowls.... and how much power you need..... how fast you want to go.... how you want to maintain the engine..... and how easy it would be to maintain.... and how often you want to overhaul it.... and just how easy would it be to fit to your airframe?

I've seen a couple of WRX turbo flat fours being used and reduced roughly 4:1, and have heard of plenty of porsche 6's and a Subaru flat six getting the big turbo treatment.

How much do you want to spend?

Then again, there are probably better opinions from those more involved in homebuilding than I.

[flyboy007]

All true. Guess I want to spend as little as necessary to achieve a reliable, suitable airframe/engine combo. Ideally about 250 horse power.

[tinpis]

Fact these engines use mo-gas or in a diesels case avtur is the single biggest advantage

[Feeton Terrafirma]

There are a few small A/C in Oz with the Chev GenIII LS1 alloy V8 in them. Reports indicate they are very reliable and low maintenance, but the one issue so far has been with the reduction gearing not being able to take torque load in the longer term. The LS1 in my car is good for 405 hp (300kw) and 376 lbf feet (510 Nm) which should be enough for a 4 seat a/c

Have a look at the options here (http://www.homebuilt.org/vendors/powerplants/auto.html)

[Whiskey226]

I read in a kitbuild magazine recently an article about some crazed speed demon putting a chev LS1 into an RV6, with outstanding effect - he had to throttle the thing way back in the cruise to avoid exceeding Vne.
My concern with the whole auto engine in aircraft idea is reliability. Since auto engines are designed to a price amongst other things, they are not designed to take high power loads for extended periods of time. Try driving around with your foot flat for 100,000kms and see what happens! A lot of the time what happens is the cooling fluid gets superheated and vaporises around the hottest parts of the engine, causing a mass loss in cooling efficiency and eventual failure.
In the LS1s case, it was designed for cars as well as industrial applications and as such has a 100% duty cycle, ie, flat out all the time. It has some sort of vapor separator around the heads which eliminates the vapor problem. With head modifications I guess almost any well engineered or understressed engine could be adapted to the application. Just depends on how far your back pocket can stretch, and how much you lerve that awesome V8 sound at full throttle:E

[currawong]

Come on Whiskey226, spend some time working on current aero engines and tell me they were not built to a price (and a 50+ year old specification)

But your point does stand - have seen a hugely expensive and ultimately unsuccessful attempt to put a Ford Nascar type engine into an airframe. Years of R & D for something that did not work.

For my money, watch some of the new turbine powerplants coming onto the market for homebuilders:E

[Whiskey226]

Hey Currawong,
Didn't even start on aero engines! I'm all for having a bit of this-century technology put into dedicated aero engines, been watching the development of the new diesels and turbines with interest.
I just find it infuriating how a 360ci auto engine has no probs producing 400hp while a 360ci aero makes 200...
Having said that though, I've never seen an auto engine continue to produce power with one cylinder completely blown off and the conrod sticking through a hole in the crank case...
;)

[Milt]

Didn't the rebuilt Vickers Vimy have 4 x V8 car engines installed for its flight England to Oz a few years ago?

[currawong]

It can be done - but deleting the flywheel and going budget on the gearbox are things to avoid from what I can gather.

[Ozgrade3]

Oh to have the technology and sophostication of modern automotive engines in GA aircraft. Just to think what Mercedes AMG, BMW motor sport, Ferrari, Lamborghini could do.

I know Porsche had a go in the 80's with the Mooney PFM. Its lack of success ws more due to the rediculous certification requirements laid out by the FAA at the time then any technical issues. I can vouch that on takeoff as it passed overhead it sounded bloody brilliant.

Imagine a Ferrari F430 V8 engine under your cowl. Take a look at the engine in the December 2004 issue of Wheels magazine on page 74. Makes me drool just looking at it.

Toyota did indeed gain a type certificate and production certificate for the Lexas 4 Litre, quad cam V8 out of the Lexus. Theoretically, they could manufacture and sell this engine any time they want.

However, according to an AVWEB article, the reported $200 million USD cost was little more than a dry run, its aim was simply to gain experiance in designing and certifying an aero engine and was never bound for for the showroom floor.

The article also goes on to show how Toyota has a 50 year plan to gain total market dominance in the GA, secretly designing a range of GA airraft including engines.

Anyone who dismisses this idea should think back only 30-40 years or so in the automotive industry, back then, anyone who said that most of the world would be driving 4 cylinder Japanese cars was laughed out of town.

Just take a look at the average carpark these days.

Me thinks the great GA manufactures of yesteryear, Lancair and Cirrus excepted, are living on borrow time.

[Fred Gassit]

Your average car on a flat highway is using around 25% of rated pwr, huge amounts of money were spent trying to produce a reliable (TBO comparable with existing a/c engines) powerplant from the Northstar (cadillac?) V8, features such as EFI and CDI improve efficiency a lot and should have been utilised years ago but I think by the time you make one of these engines reliable for anything approaching 2000 hrs the cost is getting way up there

[currawong]

Agreed, but -

2000 hours at 100 km/hr = 200,000 km

Many modern car engines, run in this fashion are good for a lot more than that.

[Fred Gassit]

thats 2000 hrs at 20 to 30% power (average) as opposed to running very close to wide open in the a/c case (2000 hrs at say, 200 km/h?) , Im sure the new generation of a/c engines will be great but a combination of low volume production and necessary structural integrity will ensure they are just as expensive as current options, at least they should (are) much more efficient, does anyone know what the diesels available for C182, Katana etc are costing?

[karrank]

Hello Fred, bin a fan of yours for years!

Thielert Centurion (Diamond/Twin) 42,000 eurobucks plus fadec!

Deltahawk DH160 - 23,500 septicbucks, but first deliveries have slipped from SEP04 to MAR05, so it may be a dream.

I'm very much taking to heart my dream aircraft's designer's opinion that a Cozy is not something experiment in engines with, and this would apply to any other hottie like a Lankair. He's not even real keen on new engines, and recommends used, half-time engines. Certified type. I like the way Rutan's Voyager flew first on 'rag-overhauled' engines, (ie. they bought two engines from wrecks, wiped them with a rag and bolted them on.)

On the other hand there are plenty flying with 13b Mazda rotary, turbo and not. Subaru EJ22 & 25 in fair numbers. Lots of lighter types with EJ18.

[poteroo]

There are over 3000 VANS aircraft actually flying, and about twice as many kits under construction.

When asked what's the best,most reliable,most economical engine to put in an RV, Dick van Grunsven is quoted as saying fit a Lycoming and you'll never regret it I concur.

The real problem at present is that all the 'used' Lycomings have long since been snavelled up for kit aircraft.

Under 'EXPERIMENTAL' you can fiddle with lots of engine options, but in the future - who'll buy the unusual one off you - if you need to sell?

happy days,

[criticalmass]

Aero engines are designed to deliver continuous levels of high output for their rated TBO time. Automotive engines are designed to deliver power via transmission systems and only produce their maximum rated output for short durations during acceleration as the vehicle shifts through the various gears, either under manual control (which allows higher revving prior to shifting) or via auto transmission systems.

As such, they are fundamentally different in their thermodynamics, fuel mixture requirements, cooling systems, ignition systems, servicing intervals and longevity.

The cost of adapting just one auto engine to an aircraft application is in many cases at least as great as that of a zero-hour rebuilt aero-engine. Cooling system modifications, fuel system modifications, weight-reduction programmes etc will raise the cost yet further. If this is successful, then the engine (re)builder has the option of converting additional engines, hoping to recover part of the R&D costs by economies of scale as the number of converted units increases. This assumes his conversion produces the desired power and achieves the desired TBO time as well as meeting servicing intervals without failure or excessive replacement of components.

Some automotive engines seem inherently to lend themselves to suiccessful aero conversions. The Type 4 VW engine is well known, the Corvair engine is also successfully converted in numbers, and the Subaru EA81 aero-conversion is well-established, finding particular application here in Australia with sport rotorcraft (gyros etc).

However, these engines are the exception to the rule. Someone trying to convert a Jaguar V12 engine, for example, for their replica Spitfire or Hurricane is going to be a very disappointed man with a large hole in his wallet to boot - and probably a non-flying airframe into the bargain.

Asking an automotive conversion to deliver 250hp, reliably, at full power for hours at a time is a big ask. It's one thing to do this for brief periods when you're sitting in a nice engine bay with a water-cooling system and a transmission to absorb that power and deliver it to the wheels, it's quite a different affair when you've been stripped bare of all but the absolute essentials to keep you running and you're now expected to deliver that power all the time.

Recent developments in aero-diesels, burning Jet A1 rather than automotive diesel, offer some promise. I think this is the next great area of advancement in piston aircraft engine design. The flat fours, sixes and eights are firmly in the hands of Teledyne-Continental and Textron-Lycoming.

How well Wilksch, Thielert, SMA and the other diesel aero-engine manufacturers fare in the next decade remains to be seen. If there is to be a breakthrough, this is where it will be, rather than converting existing automotive engines for aircraft use.

[OZBUSDRIVER]

criticalmass Just a quick point, Thielert are using Daimler-Benz auto diesels as the base conversion. Will be interested to see the 4litre V8 does:ok:

[Ozgrade3]

Some of the arguements on this thread seem ill-informed and wide of the mark.

Of course it is absurd to think that you could lift an engine straight out of a car, stuff it under the cowl of an aircraft and expecting to give full rated horsepower indefinitely. Car engines ar built to be just strong enough for their intended purpose using the minimum quality of parts to get the job done and no more. A typical latest V8, the GEN4 LS2 6 litre V8 as featured in HSV's Club Sport R8 has a rated power of 297kw. however its maximum continulus output would be little nore than 60% of that, say 180 Kw. Its must be noted that the engine cost to HSV is budgeted at around $2,500 per unit. In that we can assume that the engine is built down to a price.

Today I asked a mate of mine who has 30 years experiance in the engine bulding business, what can be done in buildigan engine. he has build dragster and race engines for many many years.

Using specialist parts from suppliers, available in catalogues. Block, crank, conrods, pistons, fuel injection systems etc etc he said 350 Kw (430 hp) was easily available and as much as 550-600 hp can be achieved if u go for the topshelf equipment. Additionally, the hp ratings were continuous ratings, able to be delivered day in day out. These parts are race developed and proven over many years of Indy, NASCAR and various other motor sport categories. They are built to do the job and cost commensuretely more.

Cost for the 430 hp would be around $45,000 mark and around $70,000 for 600 hp.

Anyone priced a brand new out of the Box Lycomming TSIO-550

[Like This - Do That]

The STCs or similarly authorised installations of Thielerts etc are in PA28s, C172s and kits. Obvious I suppose as these make up the biggest market.

I haven't seen if anyone will be fitting this type of engine, ie the diesel/avtur burners, to aerobatic aircraft. If the leaded fuel era comes to a close what will the Pitts and Extras have in the front?

Alternatively will the Lycomings and Continentals keep running but on ULP with something like GAMI's pending PRISM?

Cheers