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Flat 4 or 6 cyl Aircraft Engine

leeschaumberg

leeschaumberg

Well Known Member
Building a sell able diesel aircraft engine in the USA can be very cheap and easy if the designer is smart. One must keep in mind not to try to reinvent the wheel. The need for a high rpm engine (gear reducer) is not needed or wanted. The crankcase can be CNC machined out of billet aluminum. Crank, rods, piston, cylinders, and valves have been designed and proven.
The ideal engine would be liquid cooled, turbocharged, intercooled and no bigger and heavier than the original o360 or o540 engine. This way the engine could retrofit many aircraft out there. Durability is a prime concern of any aircraft engine. Easy service and a good warranty would make it a hit with A&P mechanics.
So how about this for engine specs to compare to the Lycoming o360.
Horsepower - 200 normalized to 18,000 feet.
Size - 33.4 inches wide
Warranty - 3000 hours plus
Cost to Service - Oil, filter, valves, and inspect (3 hours)
Constant Speed Prop - Yes
Purchase Price - Cheaper than the Lycoming
Control - One lever control
Instrumentaion - Dual

I have the knowledge to design not the money to build and sell these engines. My time could be traded for not paid for.
I am an instrument rated com pilot.
I know how to effectively and cheaply promote a new product.
If this information interests you please call or write me at
Lee Schaumberg
6972 Orchard Ln
Appt 5B
Three Lakes , Wi 54562 715-546-3907
 
Nothing but an air cooled engine will work!

Didn't anyone tell you that only air cooled aircraft engines will work in an airplane!:rolleyes:
 
Engine

I guess we are a whole country of dummy's not to have done this already.:rolleyes: Is there something about being an instrument rated commercial pilot that would make anyone want to invest many millions to get something like this into production for such a small market? If it's such a great concept then go to one of the engine OEM's. I'm sure they don't have the internal smarts to make something new that is commercially viable. :cool:
 
Why Build a flat 4 diesel?

Millions aren't needed and NOBODY builds a diesel aircraft engine except the bankrupt folks in Germany!
 
leeschaumberg said:
Millions aren't needed and NOBODY builds a diesel aircraft engine except the bankrupt folks in Germany!
Click to expand...
I myself love the idea of a new alternative to the existing choices of aircraft engines. However, the idea of investing in a business that faces some very formidable risks would not be for me. To follow such an example as this reputable German company down the same road that could very easily, within a few months or a couple of years, bankrupt a company, does not make me feel all warm and fuzzy about wanting to jump into investing in the production of a new design of anything.

Quite frankly, I am bumfuzzled how anyone could stomach the ridiculous risks that would have to be faced to make a success out of designing, building, manufacturing, marketing, selling any new design in today's environment of lawsuit happy people. The second one is successful at anything, there are those who will try everything in their power to get "someone to hand them millions of dollars". They could care less how much effort had to go into making that new "whatever" work. So, at the expense of the hard working individuals who had a good idea and tried to make something positive happen they think they can live the easy life.

Well, my .02 on investing in a new idea even if I think it is a worthwhile idea.

Live Long and Prosper!
 
Aircraft Diesel

The Brits do have an aircraft diesel but I have never seen one and don't need to. The engine configuration is not the well balanced flat four. NOBODY in this country has ever built a piston aircraft diesel engine to sell. Because LL100 is so cheap now JP4 could be a better alternative. Not wanting to discuss the whys and whos I won't. I have never called any one a dummy and don't intend to. The price of setting up for manufacture is well less than 1/4 million dollars.
 
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leeschaumberg said:
The Brits do have an aircraft diesel but I have never seen one and don't need to. The engine configuration is not the well balanced flat four. NOBODY in this country has ever built a piston aircraft diesel engine to sell. Because LL100 is so cheap now JP4 could be a better alternative. Not wanting to discuss the whys and whos I won't. I have never called any one a dummy and don't intend to. The price of setting up for manufacture is well less than 1/4 million dollars.
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The Wilksch are 3 and 4 cylinders two stroke diesels, and perfectly balanced, at least the 4 cylinder. A flat 4 - 2 stroke will also be balanced, but there will be two cylinders fireing at once, a V4 - 2 stroke is probably better, but not as good as a straight 4 ?? hmmm
 
leeschaumberg said:
The need for a high rpm engine (gear reducer) is not needed or wanted..........

Horsepower - 200 normalized to 18,000 feet.
Click to expand...

I disagree.. by doubling the RPM you can halve the capacity and make exactly the same power which means the pistons and rods and crank and block etc can be made smaller - which means same power for less weight.

PSRU's can be made to work very well if dome correctly. Rotax engines are nice and small and revvy - good power and light weight

Cheers,
Matt
 
Lee,

I hope you find some financing. What you are proposing sounds strikingly similar to what the Rotec guys did, only they wanted to build a radial.

There is very little risk in the experimental arena from a liability stand point.

If you design the engine in a CAD program, you can send the files off and have the parts arrive at your door in a matter of days. No tooling required of any kind. The best thing to do is size it to accept existing pistons, connecting rods, valves, etc.

I know inline 6 cylinder gasoline engines are naturally balanced and produce gobs of torque. However, I don't know if that is also true about diesel engines. Of course, and I-6 is a packaging problem due to its length.

The other question I have regarding diesel aircraft engines is, the Germans had them in WWII, why did they give up on them? Was it because the end of the war stopped production? I've never gotten a good answer to this question.
 
N941WR said:
Lee,

<<Snip>>


The other question I have regarding diesel aircraft engines is, the Germans had them in WWII, why did they give up on them? Was it because the end of the war stopped production? I've never gotten a good answer to this question.
Click to expand...


If I recall correctly, several countries had diesel aircraft engines before and during WWII. They were primarily suited to larger aircraft such as bombers, being heavy, but with good fuel consumption per hp. They were suited to being highly boosted, so they were a good choice for high altitude applications such as reconnaisance.

My guess is that the Germans and everyone else moved away from all forms of piston power once they realized the turbine was going to be the future.

Besides, towards the end of the war and for a decade afterwards, they (the Germans) barely had the resources to put food on the table, much less continue development of diesel engines for aviation.
 
Reply from N941WR and KB

Thanks for the replys and now some answers. The inline 6s share perfect balance (no counter balancer) for gas , diesel , and 2 strokes.
The Germans did not pursue the reciprocating diesels because they had developed the turbojet already. Back then fuel cost was not a problem only top speed.
 
aircraft diesels--

I think designing and building a new engine, be it a diesel, gasoline or turbine, would cost many millions of dollars.(my guess-75 to 100 mil)
Look at Theilert. Look at Innodine. Look at all of the ideas, engineering, blood sweat and probably tears that couldn't be brought to frution, usually because of lack of financing. Building a diesel to do what is needed in aviation would be very difficult. (were it not so very difficult, many would already be working to perfect the engine we need) Piston engines, whether gas or diesel, will probably not be the future of aviation propulsion, unless we find a new fuel. The 20% to 30% more energy available in heavy fuels will not fill the bill if it costs $10 or $12 a gallon. We need a breakthrough in new technology. I think we have almost hit our limit with our 20th century technology.
 
victor said:
I think designing and building a new engine, be it a diesel, gasoline or turbine, would cost many millions of dollars.(my guess-75 to 100 mil)
Look at Theilert. Look at Innodine. Look at all of the ideas, engineering, blood sweat and probably tears that couldn't be brought to frution, usually because of lack of financing. Building a diesel to do what is needed in aviation would be very difficult. (were it not so very difficult, many would already be working to perfect the engine we need) Piston engines, whether gas or diesel, will probably not be the future of aviation propulsion, unless we find a new fuel. The 20% to 30% more energy available in heavy fuels will not fill the bill if it costs $10 or $12 a gallon. We need a breakthrough in new technology. I think we have almost hit our limit with our 20th century technology.
Click to expand...

The OP is basically proposing what the RST V8, the cyclone V8 and the radical V8 are. They're all gas racing engines derived from motorcycle engine pistons, rods and cylinder head assemblies. Basically all three companies had to have cranks, and crank cases (one even used the bike cylinders!) machined (for prototypes) then cast (for production, in the case of radical and rst).

I'd submit that while doing a turbo diesel would be more complicated than a gas engine, it wouldn't cost anywhere near 75 million. Would it cost Ford or Lycoming that much? Maybe, but a small group of engineers with the right competencies could have a prototype in a year, and productions engines in another year. Cylinder head design is the problem; less so if you stick with an air-cooled design, which is what I'd prefer. A large capacity air-cooled diesel 6 cyl with moderate turbo charging, lots of intercooling. The problem is the testing and modeling needed to get the combustion chamber and port design right. I'd just steal the common rail injection bits off one of the new crop of european car diesels.....
 
victor said:
I think designing and building a new engine, be it a diesel, gasoline or turbine, would cost many millions of dollars.(my guess-75 to 100 mil)...
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Victor,

I have to respectfully disagree with you. Again, look at what the guys at Rotec were able to do. Granted their radial is not certified but after some experience in the experimental market, they might certify it. Then again, they really don't need to certify it to put it on an LSA, which has already happened.

Also, I would think designing a radial from scratch would be much more difficult than designing either an inline, V or H configuration engine.
 
No doubt that a small group of the right people can bring a new design to fruition for well under a mil or two using many off the shelf components and running the show properly from the start without a bunch of wasteful frills. Prototyping costs are way less today than even 10 years ago.

My vote is for an opposed four with about 4 liters displacement, pushrods, direct drive, 8 valves, some healthy boost and it could be air or liquid cooled. Forget the common rail injection as this would be stupid expensive to develop for a diesel IMO. It was not a great idea for Thielert. Go with a mechanical Bosch pump and injectors.

I say power to you if you can find the seed money.:)

Don't forget the most important part- some of the money goes to an RV7 airframe to hang the engine on and fly it lots (like 4000+ hours), proving to the world that it works and has some good numbers for weight, hp, TBO and SFC and have a complete FF kit including proper rad setup if water cooled. Keep your mouth shut until it delivers on all goals and then sell it for under $20K. Build this and people WILL come.
 
Combustion

Diesel combustion is a bang at very high pressure and petrol is a slower flame path burn at much lower pressure, therefore diesels need to be much more mechanically stronger and the bang gives a much higher impulse spike that has to be absorbed by the engine, prop, airframe combination. Note vibration damper on the centurion.

Also as an asside, recently I took an engineer from a specilist car company that tests engines for some of the main car manufacturers for a flight. As an engineer I was curious to what he did and he described to me what they did in preproduction tests, dyno then into cars etc, all this before a customer gets to drive one on the road. Out of idle curiosity I asked him how many engines were in a preproduction run. I was staggered by his reply. "500"

So IMHO the task of bringing a new diesel engine into aviation would be a non trivial exercise. I wish anybody who does this the best luck as we could use an engine like this, and I wish someone would do it and make a real success of it.
 
sma

Expensive, alot of fuel could be brought for the difference even at european prices. Heard it was a tad heavy too.
 
Unless the engine is somewhere close to the price of current, proven engines, it will never be a big seller. Small sales equals high unit price to recover investment dollars. The mechanical aspects of the engine are important but if the project is to survive, the business plan and how the project is managed are equally important to long term viability. This is where many of these things fail. Good backing and good management is essential.
 
Thanks to rv6ejguy

My vote is for an opposed four with about 4 liters displacement, pushrods, direct drive, 8 valves, some healthy boost and it could be air or liquid cooled. Forget the common rail injection as this would be stupid expensive to develop for a diesel IMO. It was not a great idea for Thielert. Go with a mechanical Bosch pump and injectors.

I say power to you if you can find the seed money.:)

Don't forget the most important part- some of the money goes to an RV7 airframe to hang the engine on and fly it lots (like 4000+ hours), proving to the world that it works and has some good numbers for weight, hp, TBO and SFC and have a complete FF kit including proper rad setup if water cooled. Keep your mouth shut until it delivers on all goals and then sell it for under $20K. Build this and people WILL come.[/quote]


Thanks for the kind words and seems that you are thinking like me. One thing tho a RV8 tail drager is better.:D
 
I was thinking that there are many more RV7s sold than -8s so you would have the most popular FF installation already done on the test mule to stimulate sales when engine testing is complete. You could do the -8 next.:)

I truly believe something like this is possible on a smaller budget with the right team.
 
One problem I foresee is using "off the shelf" parts--------as was stated before, power pluses in a diesel are way different than a gas engine. So are forces generated in the compression stroke (think about inertia here, and TV), which is another reason diesel engines usually have a heavy flywheel.

If you are looking at using "off the shelf" parts, make sure they can survive long term in the diesel environment.

Anyone remember when General Motors put high comp heads/pistons on a small block, and turned it into a diesel------------:(
 
With a diesel, you may be limited to rods, bearings, rings, pushrods, rocker arms, valves, springs, sprockets and guides for off the shelf components but this is a massive cost saving already. Many of these race parts are dirt cheap by aviation standards and equal or better quality.

JE can whack out some pistons in about 2 weeks for maybe $120 each to any spec.

Cranks, cams, cases and heads would still have to be custom made but that is what CNC machines are for. Custom 4 cylinder race cranks can be had for $1000- $1500 in one off quantities.
 
rv8or said:
Diesel combustion is a bang at very high pressure and petrol is a slower flame path burn at much lower pressure, therefore diesels need to be much more mechanically stronger and the bang gives a much higher impulse spike that has to be absorbed by the engine, prop, airframe combination. Note vibration damper on the centurion.
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Actually, the pressure inside the combustion chamber is the same for two comparable engines (diesel and otto - aka gasoline). The difference between an otto cycle and a diesel cycle is that in an otto cycle, the heat is tranferred at constant volume, while in a diesel cycle the heat is transferred at constant pressure. In an otto engine, the air-fuel mixture burns very rapidly (explodes more or less) when the piston is at top end center and creates pressure (at constant volume), while in a diesel engine the fuel droplets burns at a much slower rate while the piston is moving down (at constant pressure). An otto engine with a CR of 9:1 have the same internal pressure as a diesel engine with a CR of 20:1.

This is also why diesel engines have much higher torque at low rpm than a comparable otto engine, the working stroke lasts much longer. A diesel engine does not have more peak force on the pistons, it only lasts longer. The reason why a diesel will be limited in RPM upward, is because at high rpm there will not be enough time to burn the fuel.

I think the SMA is as good as it gets regarding air cooled direct drive 4 stroke diesel with mechanical diesel fuel system. A 4 L version would probably have around 170 HP, but it would still weigh around 320-350 lbs or something.
 
The modern direct injection gasoline engines have comparable torque and higher hp than the latest diesels. Case in point the new 2.0L Audi TFSi which has identical torque to their 2.0L TDI and 41 more hp. Both engines have very low peak torque rpms thanks to variable geometry turbos.

I've never found any historical evidence that naturally aspirated diesels have greater torque than an Otto cycle engine of the same displacement. It is hard to find a naturally aspirated diesel these days because they perform so poorly. A look at the late '70s vw 1.6 diesel shows only 48hp and 56 ft./lbs. vs. the gas 1.6 at 78 hp and 83 ft./lb.

Adding turbos to either engine type is the real torque producer and why turbos are so vital on diesels to make any serious hp.
 
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SvingenB said:
An otto engine with a CR of 9:1 have the same internal pressure as a diesel engine with a CR of 20:1.
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Not on the compression stroke. It will be higher on the diesel, with a corresponding pressure applied to the crankshaft in opposition to the direction of rotation. This is what I was referring to above--------this resistance to the crank rotation tries to causes flex in the crank, and is part of why diesels have such massive cranks, and flywheels, as compared to gas engines.
 
The price of fuel (all fuels) will make this conjecture irrelevant before any significant engine designs could be brought to market. Hopefully the gold rush investment in batteries (for the auto industry) will provide a viable solution we could use in light aircraft.
 
SvingenB said:
An otto engine with a CR of 9:1 have the same internal pressure as a diesel engine with a CR of 20:1.
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I hope you don't spend too much money designing your diesel engine Mr Svingen, because you will be in for a rude shock when it fires up! ;)
 
Andy_RR said:
I hope you don't spend too much money designing your diesel engine Mr Svingen, because you will be in for a rude shock when it fires up! ;)
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You can relax, I have no plans developing a diesel anytime soon, turbines on the other hand :D

I know equal pressure is a rude simplification (as my understanding of diesel engines are :) ), but as far as I know the "problem" with a diesel is loads of pressure at low rpm where you don't really need it in a car, and nothing at higher rpm when the pistons start to run away from the pressure so to speak due to the slow burning fuel. In the narrow rpm band where the diesel actually work fairly close to the diesel principle, I can't imagine that the pressure is significantly higher than in an otto engine. I mean the whole idea of a diesel is to transfer heat at constant pressure, that is - expand the gas at constant pressure throughout the stroke and thereby creating massive amount of torque, mostly due to max amount of force on the piston when the "lever arm" to the crank is at optimal position.

An equal displacement otto engine, to produce the same amount of work at the same rpm, will have to increase the pressure from the compression, by combustion, to a higher value than what is needed in a diesel engine because max pressure will be closer to top center than in a diesel. But I guess this is inpractical/impossible, and it is easier to simply increase the rpm in an otto engine since you are not limited by the slow burning diesel fuel.
 
I don't see any evidence that diesel engines produce "massive torque" compared to Otto cycle engines. This is a misconception constantly re-perpetuated. Hp does the work in moving airplanes or cars, not torque which is simply force. The higher working rpm on Otto cycle engines also allows us higher gearing ability compared to diesels. The result is the Otto cycle engine will easily outperform diesels in specific output and output per unit weight. Only in fuel economy is the diesel superior due to it's higher thermal efficiency.
 
rv6ejguy said:
I don't see any evidence that diesel engines produce "massive torque" compared to Otto cycle engines. This is a misconception constantly re-perpetuated. Hp does the work in moving airplanes or cars, not torque which is simply force. The higher working rpm on Otto cycle engines also allows us higher gearing ability compared to diesels. The result is the Otto cycle engine will easily outperform diesels in specific output and output per unit weight. Only in fuel economy is the diesel superior due to it's higher thermal efficiency.
Click to expand...
If you don't believe it, try it. Take a 2L Golf diesel and a 2L Golf gasoline with manual transmission (or whatever the displacements are these days, 1.9?). Preferably you should chose a diesel model before common rail, since the common rail electronics tends to increase power when the engine rpm goes below idle.

Start on a dirt road, put them in first gear and let go of the clutch fairly fast. The gasoline will stall, while the diesel will spin and run. With the diesel you can even start in third gear without touching the throttle.

Edit: Another thing you can try. Since the common rail controller tries to prevent the engine from stalling (at least on some engines), this is a good example of the low rpm torque. Just set it in first or second or even third, and the car will go steadily uphill, downhill and so on at 900 - 1000 rpm.
 
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Torque vs RPM

SvingenB said:
If you don't believe it, try it. Take a 2L Golf diesel and a 2L Golf gasoline with manual transmission (or whatever the displacements are these days, 1.9?). Preferably you should chose a diesel model before common rail, since the common rail electronics tends to increase power when the engine rpm goes below idle.

Start on a dirt road, put them in first gear and let go of the clutch fairly fast. The gasoline will stall, while the diesel will spin and run. With the diesel you can even start in third gear without touching the throttle.

Edit: Another thing you can try. Since the common rail controller tries to prevent the engine from stalling (at least on some engines), this is a good example of the low rpm torque. Just set it in first or second or even third, and the car will go steadily uphill, downhill and so on at 900 - 1000 rpm.
Click to expand...

As Ross said torque does't do any thing horse power does! A diesel will typicly have a much better BSFC. Lee
 
Subaru Diesel

Wouldn't the Subaru flat 4 diesel be a good place to start when making small batches of experimental aircraft engines....similar to what Eggenfellner is doing now with the gas engines? I would think Egg is in the best position to transition to diesel. I'm curous to hear from Ross and Jan on this.

Bevan
 
leeschaumberg said:
As Ross said torque does't do any thing horse power does!
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Well, but... horsepower is just torque times RPM (times a constant). If you want to deliver 200 hp to a propeller spinning at 2600 RPM, no way to do it without applying 404 ft-lb of torque to the propeller shaft.

So if a diesel could get you 400 ft-lb of torque at 2626 RPM crank speed, you would have a 200hp engine that wouldn't need a prop speed reduction unit, and that would be nice. But making it light and reliable seems to be easier said than done.
 
Garage Guy said:
Well, but... horsepower is just torque times RPM (times a constant). If you want to deliver 200 hp to a propeller spinning at 2600 RPM, no way to do it without applying 404 ft-lb of torque to the propeller shaft.

So if a diesel could get you 400 ft-lb of torque at 2626 RPM crank speed, you would have a 200hp engine that wouldn't need a prop speed reduction unit, and that would be nice. But making it light and reliable seems to be easier said than done.
Click to expand...

Ain't that the truth!
 
Turbos Rule!

Diesels usually have heavier flywheels and way more crank and rod inertia than gasoline engines so letting the clutch out at idle is not a valid method to compare extreme low rpm torque. If you look at the torque peak rpm of most auto turbo engines these days (diesel and Otto) they are often below 2000 rpm. Breathing is good at this low rpm and the turbo is already shoving lots of air in thanks to variable geometry turbine devices used today.

Turbos are where it's at for torque and hp with small displacement engines- which is why most things I own are turbocharged. Just wouldn't be fun otherwise.:)

I don't think anyone would even think of an atmo diesel these days because it would be a total dog. I was looking at a small, mobile diesel cement mixer a few months ago and even that had a turbo on it!:cool:

Diesels and turbos go together like bread and jam- ya gotta have 'em, especially on an aviation application where power to weight ratio and altitude performance is important.

I say Rodney, I'll have another helping of boost please.

The torsionals from an aero diesel might be hard to tame as far as the prop went without a big weight penalty. A good damper/ absorber would likely be required or a big ol' flywheel. Diesels are pretty nasty in this regard.

The common rail injection systems used today are extremely complicated from an electronics/ programming standpoint. I'm not sure these would be a good thing to have if costs were to be kept down. This is the stumbling block for the Subaru diesel in aviation use as they are tied into the chassis electronics these days to a huge degree.
 
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rv6ejguy said:
The common rail injection systems used today are extremely complicated from an electronics/ programming standpoint. I'm not sure these would be a good thing to have if costs were to be kept down. This is the stumbling block for the Subaru diesel in aviation use as they are tied into the chassis electronics these days to a huge degree.
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The ECU algorithms are complicated, but the common rail hardware (pumps and piezo valves) is pretty robust. And you wouldn't have to duplicate all the control and sensor complexity of the auto application to get a pretty nice FADEC system for a light plane. Even a simple software controller could give better performance than old-style mechanical injection.
 
FADEC's can be simple, but you wouldn't want them to be...

Electronic engine control (aka FADEC) is a pretty simple business at the basic level. Unfortunately, in electronics nothing ever half-fails, so most of the smarts in the controller revolve around what to do when you begin to lose sensors, or identifying duff signals and ignoring them or at least choosing to do something different.

Also, once you have the capability that a microcontroller gives you, you don't want to just half use it. Most people would be surprised at the complexity in modern engine controllers, but most of it's driven by things other than engine control itself.

I've recently finished working on a clean-sheet engine controller for an Indian customer. We had 128kB storage to play with, of which more than 30kB was taken up by the communications library alone. The (fairly sophisticated) engine control stuff was relegated to about 25kB of algorithm and 15kB of calibration data. A fair chunk of what was left was consumed by the operating system, OBD functions and other non-control-related code, all of which was necessary when you have to support tens of thousands out in the field.

On other projects I've worked on, it was commonplace to download 1MB of code and data!

I'm with Ross on this one. Avoid electronics running your engines if you can at all do so!
 
Flat 4 cyl Diesel

In addition to my specs the engine will be a 2 stroke diesel. Because 2 stokes fire every 360 deg of rotation the loads would be half of a 4 stroke. This requires compressed starting air. Some people are using electric pumps but a supercharger instead of a turbocharger would work also. To be like WW2s best I'd have to make it a two speed supercharger. EH
 
Garage Guy said:
The ECU algorithms are complicated, but the common rail hardware (pumps and piezo valves) is pretty robust. And you wouldn't have to duplicate all the control and sensor complexity of the auto application to get a pretty nice FADEC system for a light plane. Even a simple software controller could give better performance than old-style mechanical injection.
Click to expand...

The multi stage injection strategies used on most modern diesels are far more complicated than on port injected gasoline ECUs. It would take much testing and experimentation to find out what works best and implement it in software IMO. Thielert had multiple problems with software, ECU hardware, wiring and even injectors. Not saying it couldn't work and be better but it will be much more expensive than mechanical injection. I also think that pilots and A&Ps will more readily embrace a mechanical system- ask me how I know this. I think gains on an aviation diesel operating at primarily constant high load would be minimal using a FADEC over mechanical injection.

I am fan of electronic engine controls on gasoline, port injected engines because it is relatively simple and reliable and proven, low cost hardware already exists plus, that is my business so I'm biased perhaps.

Perhaps the engine could be initially fitted with mechanical injection and after some money rolls in from sales, development could be started on a FADEC system to be retrofitted later if desired. Many engine projects are doomed when introducing too many new things at once as the drawn out development burns up all the time and funding long before completion. I'd prefer to see the basic design up and running on the dyno for many hours ASAP rather than having all the bells and whistles delaying or shortening the testing and validation period- then trying to deliver a mediocre, complicated and expensive engine. Test, test, test before production is key.
 
As far as doing an autoconversion, I bet that the BMW straight 6 disels would be a better fit than the subie diesel which will come with its fair share of vibration problems. The BMW should have More power (or headspace), and better torsional vibration charteristics. Possibly not ideal in terms of packaging, might even require its own airframe, I bet something like David Algie's Lp1 would be a good airframe fit as it's already setup to (hopefully) have good cooling drag, intercooling, and a long cowl.
 
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