Lycoming and Continental Piston Engines

[camel toe]

I recently overheard a rather experienced aircraft engineer talking about Lycoming and Continental piston engines used in things like Pipers, Cessnas, Robinsons etc.

He was rather damning of them from his engineers perspective and was of the opinion that they are an old design and I got the impression he felt they shouldn't still be being fitted.

I was just wondering whether there are any other engineers who work with these types of engines who can cast an opinion on the models we see in SEP's as I'm interested to hear more.

I have very little opinion as I'm not an engineer, this is purely a bit of research so I can learn a bit more.

Cheers

Camel Toe
"Over Macho Grande?"

[Pugilistic Animus]

my opinion is that these engine models are well proven well tested and simple to operate. so if it aint broke don't fix it, nothing is too new in aviation...autopilot DC-3 ca 1935 Cat II appch on AP Dc-8 1950's, most all of aerobatics 1929, autoland L-1011 ca 1965?.

anyway these OEM's have produced good reliable engines for a variety of airframes for many many years

[fireflybob]

But compare these engines to the improvement we have witnessed with jet engines over the same period which are quieter and far more fuel efficient and use digital control

Lycomings and Continentals may be reliable and proven but they are old technology! When you look at the cost of AVGAS now it's high time we had a more efficient powerplant for light aircraft which are not susceptible to (for example) carb icing.

Maybe we need to go diesel, time will tell.

[Say again s l o w l y]

If the pace of design by Continental and Lycoming were followed in the automotive industry, we'd all be driving around in Model T Ford's.

Conti's and Lycomings are rubbish and are outdated. Expensive and actually quite unreliable, especially in the larger models.

New ideas please!

[Tail-take-off]

Simple question:

Would you buy a car with an aircooled flat four/six engine with no fuel injection or electronic engine management system? I suspect not.

The problem is the certification process for advances in technology are so expensive & long winded that manufacturers just keep throwing out the same old engines despite advances which could lead to improved safety.

[Pugilistic Animus]

the FADEC controlled aerodiesels that use jetA have actually been through their reliabilty problems too, but let us introduce something much more important the bottom line and this new technology is expensive and would raise the cost of flight training in order that they meet aviation reliability [see far 23] if you have the money then there are many options, in fact just get a jet

basically they stopped working on piston recips BECAUSE of the jet engine!!!
also ,simple aircraft such as C-170 etc. are a great deal of the fun when you try to make them into 777 and a330s they just become a mess the systems are simple, the theory is simple and the maintainance is simple, and engine failure is very very rare, for any engine type---it must be so!

BTW my 88 volkswagen has been far more reliable than my 2004 nissan, never compare aviation with automobiles, those things are for the ground---who cares

[Jetstream Rider]

The Lycoming aero engine was first designed in 1932 - its a seriously old bit of kit.

It is also heavy, fairly inefficient, noisy and vibrates a lot. The cylinder heads crack, they are prone to shock cooling, often have carburettors that ice up and fail often enough to be a continuous problem in any given year.

On the other had they are proven, easy to maintain and operate, and fitted to almost everything.

Contrast though the more modern engines like the Wilksch and the Jabiru and you can see there are plenty of improvements to be made.

Your car engine of even a few years ago is likely to be much more advanced, especially in terms of noise and vibration.

If it ain't broke, don't fix it - well my cart works fine thanks, think I'll ignore these shiny new "motor carriages" - they'll never catch on.....:}

[Pugilistic Animus]

Remember also that preflight refers to checking for conditions conducive to carb or induction icing---yes I know the caveats due to the adiabatic cooling which can take place with ALL induction systems, but still, icing can take place in newer aerodiesel if the specific humidity is high enough and the cooling in the induction circuit is sufficient to reduce the temp to freezing. but as you know all GA planes with boots or a hot wing is certified to linger in known icing for hours!:rolleyes:

[ATC Watcher]

Recent debate in my club : replace the Lycoming of a C172 for 15.000 euros or change it for a modern Thielert/Diesel for 30.000 euros.

Diesel Advantages : uses diesel fuel / jet A1 at less than half the price of Avgas, slighly less consumtion as well. FADEC/ single throttle management.

Disdavantages : no-ne knows the real potential of the engine 1000- 2000 Hours ? Electric failure and the engine stops ( it happens ) , Various reliability problems , recent change of engine block , no retrofit . when using Diesel, temparature limitations. ( but not with Jet A1) Weight limitations ( with full tanks the 172 becomes a 3 seater, etc...

This combined to the fact that Lycomings are very, very reliable ( after they pass the first 100 hours ) you can see why many are still replacing Lycomings instead of going for far newer technolocy engines.
But one day, someone will come with a good new engine , as 20l/h of leaded fuel per 100 HP is a bit old fashionned in the 21st century.
But reliability is what you want above all in a single engine.

[barit1]

There is no more comfortable engine to ride behind than the Wasp Jr (http://en.wikipedia.org/wiki/Pratt_&_Whitney_R-985).

http://www.pimaair.org/images/collection/PW_R-985_PW.jpg

Just keep it supplied with fuel and 40-weight.

[Shaft109]

I recently saw an article about Honda (being the world's largest engine OEM) working on an aero engine.
They did some research and the optimum layout was a flat 4 pushrod design! but with modern fuel injection technology, lightweight components FADEC etc. The basic layout it seems is still valid, but technology in general has moved on and should be encompassed.
Can't remember any figures so will have a root around.
http://www.eaa.org/communications/eaanews/030304_tcm_honda.html

http://world.honda.com/news/2003/c030304.html

[27/09]

Interesting Discusssion

Comparision with auto engines is flawed. Yes, auto engines have shown great advances in technology, but look at the vast difference in the market size to spread the developement costs over.

Some of the technology on the auto engine doesn't operate quite so well in the aviation environment. Show me one auto conversion that has worked reliably in an aircraft? I don't count the Theirlet as successful yet, they have their issues.

Auto engines don't go to 100% output every time they operate and then run a 75% of rated power for hours on end.

Yes, your standard Lycoming or Continental isn't as smooth as your twin overhead cam 4 valve per cylinder electronic fuel injected chariot. The main reason is because the aero engine is a large capacity engine, this a product of the need for high power at low RPM. Why not run a gear box you say? Take a look at the reliability (low TBO) of gear boxes generally on aero engines of less than 9 cylinders.

A Lycoming or Continental may be old technology, genuine failures are rare and they generally go to or past TBO.

They don't stop when the gear is retracted either as happened to a Theirlet equipped aircraft recently. I know there were contributing factors, my point is they are simple and work well.

I understand that Lycoming has plans for a diesel engine but I suspect that until avgas prices get to much higher prices in the USA that progress wont be fast.

[411A]

The right engine on my private aeroplane is a Continental GTSIO520 model.
340 BHP, spur geared propellor drive, fuel injected,turbosupercharged.
It was overhauled in 1990 by Butler Aviation in Tulsa, and after 1100 operating hours, still runs like a fine watch...very smooth and quiet.

I would have to say that it has provided quite good service for its age, I certainly have no complaints.
Overhaul cost?
Depending where it's done, the price would be anywhere from $25,000 to $38,000, including accessories.
The best part about flat six aircraft engines is that if cylinder problems are found, just bolt a new one (or more) on, and continue to operate.
The bottom ends of (especially) TCM Continental engines are very reliable.
How reliable?
PrinAir holds the record, set long ago.
This small airline operated 17 deHavilland Herons years ago, re-engined with TCM IO-520 engines.
FAA allowed time between overhauls?
4000 hours.
Close attention to detail by pilots and ground engineers allowed this long overhaul period.

Treat your piston aircraft engine right, and it will last quite a long time.
Do otherwise...expect large repair bills.

[zlin77]

Following up on 411A's reply: I flew the DH-114 in Australia many years ago, ours were refitted with Lycoming IO-540's 290 hp. We operated at about 60% power in the cruise ie. 22"mp. & 2,200 rpm. Overhaul life was set at 3,000 hrs. and they were extremely reliable. Also operated Queenairs with the Lycoming GSIO-540, 380 hp.These were a different story for reliability but reasonable TBO's could be achieved with correct operation by the pilots. In nearly 6,000 hrs. of piston operations the only problem I experienced was a dropped valve in a Queenair.

[PBL]

The right engine on my private aeroplane is a Continental GTSIO520 model.

I think we knew that, didn't we?

Complex-system reliability is an art, not a science. I count IC engines as complex; I count a door, with hinges, as non-complex, although they can be quite as frustrating and unreliable.

I sat behind an IO360 for many hours, in mountains in winter, in weather, over ocean. (Well, not *that* many hours.) Cracked a cylinder, lost a mag. Ever worried? No.

These pieces of art have huge amounts of data behind them to tell you what they do. And they do their job as well as it can be done. Like a safety razor. Like a well-balanced kitchen knife.

Those are the reasons, and they are reasons that no "newer technology" can hope to match for a few decades yet.

The quandary is: how do we then progress? While answering that question, one might well remember that neither progress nor stasis is a necessary condition.

PBL

[PantLoad]

I've operated both Lycoming and Continental, and I've found both to be good, solid engines.

Currently, I operate a Lycoming IO-540 (300 HP) in my private aircraft (Cherokee Six). I fly night IFR over mountains...and most people think I'm an idiot (for that reason and possibly for others, as well...:)).

But, I believe that engine failures are due, primarily, to poor maintenance and improper operation. If you maintain the engine properly, do regular checks (including oil analysys, etc.), operate the engine as per manufacturers' recommendations, give it fuel and oil, etc....it usually won't quit. You have much higher probabilities of crashing for reasons other than engine failure.

In fact, I've never had an engine failure on a piston airplane. Had a rough-running Continental one time, but eased the aircraft to the nearest airport, made a safe landing, had the repairs made, and off I went never to have any further problems.

In most cases, engine failures are due to no fuel, contaminated fuel, no oil, intake icing, a destroyed and ingested air filter (due to poor maintenance), etc. Seldom does a well-maintained and properly operated engine just up and quit. And in the very few cases where it does, it was telling you for some time that it wasn't feeling well, and you simply weren't listening.


PantLoad

[barit1]

There's a VERY interesting discussion here. (http://www.prime-mover.org/Engines/GArticles/article2.html)

[MrBernoulli]

Ooer! Have I been lucky? I have flown 1200+ hours on single engine pistons; about 1000 hours on twin pistons - all using Lycomings and Continentals. I have also flown 1000 hours on P&W Twin Wasps. Never had an engine failure on ANY! EVER!

Now flying ruddy great GE90s and RR Trent 895s ...................

[missingblade]

Its time for the old technology to be replaced. The fact that they have millions of hours behind them do not make them efficient.

[ForkTailedDrKiller]

Hmmm! There is some complete drivel posted in here.

Show me any other engine that can match the IO520 in my Bonanza for the combination of proven reliability, power to weight ratio, cost effectiveness, fuel economy at or below 10,000' over 500 nm - apart from a similar Continental or Lycoming!

My V35B trues 160 kts at 10,000' on 48 L/hr. There is no doubt I could get that back to 45 L/hr if I had an all cylinder engine monitor and ran LOP.

There is a very good reason they are still putting them in new aircraft.

Sure, FADEC would be nice but when the price is reasonable and the reliability is there.

Dr :8

[MrBernoulli]

missingblade,

Its time for the old technology to be replaced. The fact that they have millions of hours behind them do not make them efficient.That may be so, but it doesn't make the engines mentioned above unreliable either! Solid, reliable, easy-to-service bits of kit IMHO.

[Rocker_7]

Dear Pantload (yes, replying your post of 2007 if I see it well).. :)

Can you recommend a "good starting point" educational video (on youtube or elsewhere) about oil analysis, that a non-engine-overhauler pilot can also understand ? In general, what can we learn about oil analysis ? How is it done, and - importantly - how can I determine, whether the person or workshop who (claims) is doing it well, really does a professional job ?

Thank you,

[AC560]

Dear Pantload (yes, replying your post of 2007 if I see it well).. :)

Can you recommend a "good starting point" educational video (on youtube or elsewhere) about oil analysis, that a non-engine-overhauler pilot can also understand ? In general, what can we learn about oil analysis ? How is it done, and - importantly - how can I determine, whether the person or workshop who (claims) is doing it well, really does a professional job ?

Thank you,

This video should get you started

EAA Video Player - Your Source for Aviation Videos (http://www.eaavideo.org/video.aspx?v=1149666747001)

Google Mike Busch and oil for more, quite a bit of information out there from him on all sorts of things. I would echo the comments others have made that really proper care and handling of the engine is key to longevity (even the awesome GO-480).

[Alpine Flyer]

Lycoming/Conti engines may be proven, reliable, etc., but so are hydromechanical fuel control units and horse carts.

FADEC engines will admittedly increase complexity but so are lots of other gadgets we have come to accept in the interest of economy and safety. And some possibilities of FADEC controlled engines actually reduce complexity, like replacing two magnetos geared to the engine with permanent magnet alternators and electronic ignition (or no ignition at all with Diesel engines).

("simple" carburetors have their quirks too. A club airplane lost engine power because of a stuck outflow valve (due to a broken valve hinge bearing) causing a buildup of pressure back into the induction system which effective killed the whole air/fuel mixing.)

For added complexity FADEC control would allow for single-lever power management which we have come to accept as standard in turbine engines, allowing optimum RPM/MP combination and reducing handling errors.

Current engine design owes to a time when there was no alternative to lots of displacement to turn props slowly. Today Rotax engines have run hundreds of thousands if not millions of hours with geared 4-cyl engines (admittedly of only up to around 125hp) and the Diamond Katana with its Rotax engine has captured a good percentage of the training market not least because it uses half the fuel of an O-200-powered C-150.

Liquid cooled engines would allow for more efficient cooling designs, theoretically even wing leading edge cooling providing de-icing would be an option (at least for larger engines).

Lastly it will become increasingly unfashionable (at least outside the US) to use something for recreation or transportation that uses an outdated amount of leaded fuel.

Even if we wouldn't mind using a poisonous additive in our fuel, lead content makes it more expensive to distribute AVGAS at least in the US because it has to be kept in separate distribution and storage facilities from non-leaded fuel, so it can't be pumped through Pipelines but has to be trucked or moved by barge (which then cannot be used for non-leaded fuels without cleaning AFAIK.) Coupled with a fringe market, this makes production of AVGAS unattractive for refineries, all factors increasing Price.

Honda finished their HondaJet after almost 20 years of designing, so maybe they'll come up with an aero engine some time.

To each his own. All who enjoy operating vintage machinery shall do so as long as they like but there should be a more modern option to keep GA flying viable into the future.

[LeadSled]

Folks,
There is one vital point missed in all this, the aircraft that are piston powered, as new build aeroplane, are built in small numbers.
If there was a real market for a "modern" piston engine with all the bells and whistles, they would emerge.
There have been a few tries recently, an small HP Jet A diesels are being built in small numbers, for the small number of aircraft, to which they are fitted.
A lot of money has been lost by the original developers.
Auto comparisons are just plain silly, not only because the operating conditions are so different, but far more importantly, motor car engines are built in the millions, justifying the development costs.
Tootle pip!!

[glum]

"Auto comparisons are just plain silly, not only because the operating conditions are so different, but far more importantly, motor car engines are built in the millions, justifying the development costs."

So how hard would it be to take one of the most reliable engines and qualify it for GA flight?

I read an article a few years back about a Honda Fireblade engine (918cc, 120hp) which they ran for a million miles. When they stripped it, all tolerances were within limits.

Now I appreciate this is on a test bench and the atmosphere controlled, but I would expect that many of the advances in plating, injection, cooling, materials etc. would be perfectly applicable to GA.

Why develop from scratch if you can take something built in the millions and just tweak it for your environment and qualify it...?

[DirtyProp]

Because the work loads of a car engine and an aircraft engine are quite different.
Most likely just some tweaks won't do it.
Apart from that, if you want to use an engine on an aircraft it has to be CERTIFIED. And that means a lot of paperwork with HUGE costs for the manufacturer.
Is there a market big enough to offset those costs? Unlikely.

[Radix]

.............

[Chu Chu]

I'm curious how great the efficiency gains from things like electronic ignition and fuel injection are on an aircraft engine. On a road vehicle, the computer makes a big difference be ensuring that mixture, timing, etc. are optimized all the time.

But it shouldn't be that hard to set up old-fashioned carburetion and ignition for maximum efficiency in one condition -- cruise flight. Once you have that, how much more will a bunch of silicon add?

[barit1]

In the commercial world, and upper-end business aircraft, VERY HIGH reliability and ever-improved fuel burn are paramount, because of their effect on operating costs. Airlines effectively underwrite the engineering and certification costs of manufacturers to achieve these ends.

In the private/training aircraft market, the cost pressures of the airline market just don't exist; ergo no such underwriting of the manufacturer's costs.

(Just send me a freshly overhauled R-985, an 85+ year old design, and I'm happy!)

[Uplinker]

But it shouldn't be that hard to set up old-fashioned carburetion and ignition for maximum efficiency in one condition -- cruise flight. Once you have that, how much more will a bunch of silicon add?


A lot more reliability for one thing, and better starting and power delivery in the take-off and climb for another. ECUs optimise the ignition timing and the charge in the cylinders hundreds of times a second, and the engine therefore runs at peak efficiency and reliability at all power settings and atmospheric conditions.

Carburettors are very crude mechanical devices and are prone to icing and malfunctioning. Can any piston aircraft manually adjust their ignition timing whilst airborne?, I've not heard of that, but have only flown SEP and MEP Cessnas and Pipers etc

Of course, efficiency is of little concern to the SEP and MEP world, and a simple, large displacement magneto engine will run with no external electrical power, which has a certain advantage.

It was similar in the car world, where we used to have large capacity engines to ensure sufficient power in all conditions. Nowadays with electronics we have engines half or a third of those capacities but which are just as powerful, and more reliable and cleaner. In addition they will adjust themselves to prevent pre-ignition (knock) and will not allow themselves to be overrevved etc.

[Fly4Business]

Lycosaurus and ContiRex may be thought of as old and outdated, but I have to admit - I do like to fly them.

They do what I tell them to do and when I tell them, they are real easy to run and maintain by anybody with common sense, I am able to understand how and why they function, even guess quite quickly when they don't. The carb will give me direct feedback on environmental conditions, where already the injected engine is mysterious as my girlfriend.

The one I fly frequently now, already turned well over 50 years old and is still going strong on 3rd overhaul with no end in sight. I don't see a real progress in piston engine development either. I have to admit, I neither trust the car derived Fadec piston engines, nor things like Jabiru (which I would not call blessed with reputation anyways).

Maybe I have to fly too much turbine and jet, but I would like to see the old basic flying available for a long time. Call it sentimental, I call it joy of flying.

[megan]

What we are realy interested in is the fuel consumed to create the horsepower ie the specific fuel consumption.

For a Lycoming IO-520F operating leaned to peak at 74% power the SFC is 0.413 lbs/HP/hr

For the R-3350, which is claimed to be one of the most fuel efficient spark ignition engines, the figure is somewhere between 0.409 and 0.398 depending on whose figures you use

Using the best figures I was able to find for a BMW 328i the figure is 0.446 for highway motoring, where it is only using 24 of its available 250 horsepower

So I would say the Lycomings/Continentals are not doing too bad. Spark advance (electronic?) and GAMI injectors to properly balance fuel distribution between cylinders would be about the only advancements possible IMHO. The stuff hanging off a car engine these days is mostly to satisfy pollutant control. I'm told they can't be operated at LOP because of the catalytic converter and O2 sensor, not much use to aviation where LOP is standard fare for the knowledgeable and properly equipt operator.as 20l/h of leaded fuel per 100 HP is a bit old fashionned in the 21st centuryIf you can build an engine that puts out 100HP with a 20 litre fuel burn you've just found a way to print money, as that represents a SFC of 0.313, an absolutely unheard of number. .38 is about the lowest achieved, with .35 being talked about.

[nomorecatering]

The notion that car/automotive engines are not up to standard for aviation use is now incorrect. Austro on the Diamond DA62 uses a 2 liter diesel engine made by Mercedes. The block, crank, conrods and pistons are unchanged form the car version. Todays modern automotive engines ith gasoline and diesel are pushing out hp and torque numbers unimaginable 10 years ago in consumer engines. Just look at Mercedes new 4 litre V8 in the AMG GTS. That specific power level was F1 territory 20 years ago.

The engine you buy today from Continental or Lycoming, while at face value looks unchanged for 50 years, the detail design and metallurgy means the engine is vastly different from its predecessors. 10 years or more Continental offered a blue printed line of engines at extra cost. That standard is now the norm.

However, diesels will ultimately kill of spark ignition engines for aviation, then they will be ale to standardise on 1 fuel type for the whole of aviation. Jet fuel.

Interestingly though Mazda has been experimenting with a compression ignition gasoline engine with a compression ratio of 18:1. It apparently has some super fuel injection system.

[Volume]

Just have a look at the "lycosausus small brother", the Rotax 912.
This engine has water cooled cylinder heads to eliminate the thermal shock/cracking issues, it now also is available with a FADEC, fuel injected, with a computer controlled ignition.
At full power, the carburretor equiped version (which has a lot of issues with the carbutterors, wear, synchronisation...) still performs better.
Electronic fuel injection is great where automotive engines are operated, at low to moderate power. If you go full throttle / high power carburretors are not that bad. Same for ignition, if you go high rpm / high power you are anyway at a fixed timing, no need to do that with a computer.
Looking at the SBs and ADs the Rotax had over its life, our Lycontisaurs are damn reliable machines!

Production quality and price are the only real issues with our traditional engines, which were at times 40 year ahead of the automotive industry... It is just since the mid-80s that they have become much advanced, but mostly with respect to low power efficiency and emmisions. Even now you can still buy cars that not have hydraulic lifters compensating for valve expansion under heat...

The best thing you can do to improve our engines is to learn how to operate, especially how to lean them. That gives you more advantage than the car industry had in 30 years.

[B2N2]

I shall have the dissenting voice then....
They're heinously outdated pieces of equipment.
160HP-180HP out of 360 cubic inches? That is as bad as a late 70-ies Corvette.
4 pistons the size of saucers running 2300rpm?
40l/hr at 120kts? That's 18.3 l/100km...atrocious.
My claim to fame?
Non stop flight from just outside Boston to Naples, FL in a DA-42 Twinstar with 65 gallons used. 250 liters for 2200km for 11.4l/100km in a twin engine aircraft.
I've always liked the 1.7L more then the 2.0L Thielert.
In any case these engines are the Mark 1.0..lots of room for improvement still.
But for fuel consumption and noise levels...wow.

http://www.pprune.org/private-flying/468577-personal-best-distance-endurance-flights-2.html

[abgd]

A few thoughts:

It's true that most older aircraft have 'atrocious' fuel consumption, but that's as much to do with the airframes as the engines. I've heard it said that Rotaxes are not really much more efficient than Lycosaurs and Continentals in the cruise, but that their advantages lie in climbs and circuits... Where admittedly a lot of aircraft spend a lot of time. Particularly training aircraft.

WRT car engines... if you take an engine and run it at 20% of peak capacity, it's not surprising if it lasts for many thousands of hours with little wear. But what if you put it in your aircraft and run it at 100% for minutes at a time, then spend the rest of the time at 75% power?

There are older aircraft that allow you to advance/retard the ignition; presumably it was felt that 4 levers (throttle, carb heat, mixture, pitch) was already enough for any mortal to get their head around.

Certification may not prevent engine development, but aircraft certification prevents you from just bolting a 100hp rotax to anything that is designed for a 100hp continental. Contrariwise, if you were to buy a new aircraft, would you want an engine from an unproven manufacturer who might go bust at any moment - thereby grounding the whole aircraft potentially forever - or would you get an engine from a vendor who's been around for the best part of a century and for which 3rd party manufacturers supply approved parts? If an aircraft cost £10,000 and was expected to last 10 years you might well chance the modern engine with a slightly lower fuel burn, but as a new Cessna costs fifty times that and might be expected to last 50 years, knowing that the powerplant is likely to be supported for decades to come is a big issue.

Personally I fly behind a VW engine which, five decades after it was made, is likely to have parts support for many years to come.

[NutLoose]

Rocket, this will help you

http://www.lycoming.com/portals/0/techpublications/serviceletters/sl171_sl_171_general_aspects_of_spectrometric_oil_analysis_1 1261971.pdf

http://ehfc.net/LycomingEngines.pdf

I cannot fault Lycomings and Continentals, true they burn more fuel, but they have decades of use behind them, they are known, simple and reliable, what more could you want.
As for some of the later diesels, they are none of the above.

[Machinbird]

I have flown many pleasant hours behind Lycoming and Continental engines as well as with Pratt&Whitney and Wright radial engines, but their time is drawing to a close. If you wish to fly in the Artic regions, you may have great difficulty in finding AVgas at any price. You may find that the green fiends have made it impossible to add any lead content to your Avgas, and that your engine actually needs just a touch to keep running.

There are new diesel engines on the horizon that are capable of using a wide range of turbine/diesel fuels. My personal favorite is the DeltaHawk engine which has been under development for the last 20 years.
It has been a painful process to watch from the outside and has cost a small fortune, but they are drawing very close to the certification target. It is not enough to have a brilliant concept. In the end, you need to develop a wide base of engineering knowledge, qualified suppliers, proper industrial methods, proper trust from the certifying authority, etc. A very daunting gauntlet for a start up company. I wish them well.
DeltaHawk DH180A4 | DeltaHawk Engines (http://deltahawkengines.com/content/deltahawk-dh180a4)

[westhawk]

The target FAA certification date for unleaded avgas remains 2018. We'll see. According to an AOPA article from about 6 months ago, progress has been steady. So probably there is no need to worry about gasoline burners going the way of the dinosaur on account of leaded gas! Running unleaded is going to solve more than one problem.

The arguments for and against EECs for aero piston engines are well-known and long established, though perhaps somewhat less so than the tried and true magneto itself.

[barit1]

Unleaded avgas AVAILABILITY is one thing. Satisfactory testing and certification on hundreds of GA aircraft/engine combinations (seals, gravity-feed heads, etc.) may be another issue. 2018? Suuurrre. . .

[Volume]

160HP-180HP out of 360 cubic inches? That is as bad as a late 70-ies Corvette.
4 pistons the size of saucers running 2300rpm?
40l/hr at 120kts? That's 18.3 l/100km...atrocious.
You are comparing apples and oranges.
160HP-180HP? At what speed? Show me one modern car engine (even V12...) which can do 180HP at 2000rpm. They can do that at 5500 or even higher, at that speed the Lycomings can produce 350HP or more (ask the Reno-Guys...)
Going 120 kts (220 km/h) with a modern SUV is barely possible with 18.3 l/100km.

Compare comparable numbers please, but as stated before, SFC numbers for cars are hard to come by. Even l/100km values which are not just possible on special test stands with special tires, no A/C etc. but in real life are hard to come by.

Pistons may have the size of saucers, but look at their actual shape and contact area. It took the car industry up to the late 90s to produce pistons which are not just the shape of a tin can and optimized for cheap production, but optimized for weight, contact area, oil distribution, heat transfer etc. Modern car engines are now further advanced, even with some non-metallic anti friction coating in the highest contact force area, but that is a thing of the last 15 years.

Taking into account the typical speed of propellers, turbo charged direct drive diesels are most probably the way to go, but these machines are real propeller murders. The torque peaks ruin every blade root bearing... So unless we design some Propellers with elastomeric roots (similar to what the helicopter folks do) we will not get very far. Reduction gearboxes have also not proven too reliable yet, so modern high speed turbo charged direct injection petrol engines are also not that easily made.

There is not much doubt that the aera of high octane fuel is over. So somehow we must find a new way to power piston aircraft. Fast.

Maybe the club/flying school business will very soon move into electric aircraft, then the market for high performance long range aircraft will become a real challange, because it will be very, very small. And no market to develop a new engine for.

[Wageslave]

It certainly seems a pity that we have failed to modernise our light piston engines since WWII and have been running essentially the same dinosaurs since then, virtually unchanged.
This is roughly equivalent to modern cars being powered by the engine from a grey Ferguson tractor on the sole basis that it is reliable and there was "no call" to modernise it.

The white heat of technology went cold in the late '30s as far as light aviation propulsion is concerned, and is only now beginning to warm up again.

If Honda can build utterly unbreakable, utterly reliable, lightweight 150BHP engines for motorbikes it seems a shame they haven't done the same for aircraft.

Show me one modern car engine (even V12...) which can do 180HP at 2000rpm.
er...Jaguar XKR for a start. There must be more as the Jag is far from an extreme engine, though blown.

[megan]

As I've posted previously, the figure of interest in any piston engine is the SFC.

One ex car engine at least has been certified by the FAA, and used the Toyota Lexus V8 as the base. See here if you want a max power of 360HP at 5,200RPM,

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/4f36c245de33402f8525670c0069d991/$FILE/E00052en.pdf

It quotes a maximum best economy cruise SFC of .382 at 4,400RPM, though how much HP that is is not stated. By comparison Lycoming have engines that will make a SFC of .4 at 75%. Found it interesting that it has a dual channel full authority digital engine control, but only one plug per cylinder.

There is always a downside, the FV4000 was tested in a Malibu and found to be heavy, had some exhaust problems and would have been expensive to manufacture, on the order of $100,000 per unit (2002 dollars).

The factory says that B2N2's DA-42 at 60% power has a SFC of .338 as an example of diesel economy.

To reiterate, the Lycomings etc don't do too bad, given their simplicity.