A good common engine to convert?

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plncraze

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What engines are easily available to you? Perhaps something so cheap you can mess with it with out worrying about breaking and getting another.
 

Winginitt

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Don't know the actual weight of the old inline Ford engines, but as long as your engine choice doesn't weigh more than that, it should work. I like the Pietenpol design, but never liked the idea of a radiator sticking up in front. Some of them have air cooled engines and don't have that problem. Its not just a matter of the radiator blocking ones vision, but when radiator problems occur, that hot coolant could to blow back in the pilots face.
I had an old 33 Ford witha a crank out windshield. Fan belt broke and shortly hot coolant blew out and came under the open windshild. I was going about 65mph at the time. Not a pleasant experience.....but I could slow down and pull over.
 

mullacharjak

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You can put the radiator just behind or below the engine.You need to do some redesigning.In USA engine selection is no problem.For a pietenpol you can fit the aircooled Corvair engine or A65 continental.If you could increase the power of the modelA would be a good thing.Where I am from the engines normally used in a pietenpol are not available.
I thought about a Honda L15 or R18 engine with reduction drive but designing a reduction drive is beyond me.I wish someone would offer construction drawings for a reduction drive for that engine.Because of that i decided to use a direct drive engine.
That being a Toyota V6 2.5L engine used in a camry which are easily available and cheap.Its a little heavy but not by much.I have compromised and it is going to be a single seat aircraft.
 

cheapracer

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That being a Toyota V6 2.5L engine used in a camry which are easily available and cheap.Its a little heavy but not by much.I have compromised and it is going to be a single seat aircraft.
Actually the 2.5 and the 3.0 are very light, maybe not as light as the Suzuki, but light none the less. That's the very first Camry V6, the 2MZ and 1MZ, not the later, heavier ones.

The reason it's small and light is because they had to stuff it into the then current Camry, only designed for the 4 cylinder, as they were losing sales in the USA.

You may as well go for the 3.0 there such small difference, and far more common. Also if need be, the 3.0 had a TRD supercharger option that can be found still.
 

pfarber

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Not what I said, i was mentioning to people to not make the mistake of thinking something is light, or lighter, merely based on it being all aluminium. All aluminium Honda K20's are notoriously tall and heavy for a 2.0 for example, compared to a 2.2 Toyota 5S-FE, 200cc bigger, dual balance shafts and with cast iron block is lighter.

All i am saying is take each engine on it's own merits, not what it's made from, you know, just trying to help members here to make informed choices.




Compared to what? An inline 4 is not smoother than a flat 4.

60 degree V6 engines are very smooth, yes they use a balance shaft to achieve that, but the overall weight saving is enormous over a straight 6.





"In car", a Nissan V6 weighs 320 lbs, 260 to 300+hp depending on model. Plenty of V6s out there will walk over the Vortec specs.
"People should not make the common mistake of believing just because it's aluminium it is therefor lighter than a cast iron blocked engine."

Is exactly what you said. I'll ask you to show two comparable motors, one iron, one Al. where the iron one is lighter.

Yes, every engine has its merits. None are perfect. I place economic factors above most all others. A cheap good preforming engine, to me, is a better solution than something less common or more expensive.
 

cheapracer

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"People should not make the common mistake of believing just because it's aluminium it is therefor lighter than a cast iron blocked engine."

Is exactly what you said. I'll ask you to show two comparable motors, one iron, one Al. where the iron one is lighter.
I did, an aluminium Honda K20 Vs a cast iron Toyota 5S, and only to satisfy your request, but it

WASN"T RELEVANT
,

shees, your'e command of the English language is somewhat lacking to say the least .....

Ignore list, bye bye ....
 

PMD

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Direct drive automotive conversions are not really very practical. To begin with: no thrust bearing and then, crank not designed for the bending loads imposed by propeller assymetric pitch (airplane pitched) and imbalance, never mind resonance issues from aluminum props. So you have your neck stuck WAY out for crank and bearing failures. Then, the issue of RPM comes up: aspirated charge, spark ignition engines just don't work worth a **** at 2500 RPM...unless they have HUGE stroke (say up in the 5" range). Also, light engines tend to be 4 cylinder engines, and then you are DEEP into torsional resonance issues due to 180 reversals in rotational acceleration. For these reason, reduction drives are pretty much mandatory.

The ONLY way to go direct drive would be with diesel, as you can simply use turbo to make whatever manifold pressure you need to fully exploit the available mechanical strength at prop RPM, but then you still need a thrust bearing.
 

Vigilant1

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Direct drive automotive conversions are not really very practical. . . . For these reason, reduction drives are pretty much mandatory.
. . . .
The ONLY way to go direct drive would be with diesel, as you can simply use turbo to make whatever manifold pressure you need to fully exploit the available mechanical strength at prop RPM, but then you still need a thrust bearing.
Lots of unsupported generalities here.
The most successful aircraft auto engine conversion worldwide (judging by the number installed and the number of flight hours) is direct drive: The VW Type I. And its 1/2 VW cousin. Also, Corvair conversions (also very popular in the US) do very well--they are also direct drive.
 

PMD

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I have built many dozens of direct drive VWs, and can tell you that pretty much any 440cc and up two cycle twin with a redrive blows a small displacement (69 mm stroke direct drive) VW out of the water on every count. Never did a really big displacement engine, as poduction volumes meant I had to go to engines-out-of-the-box (in my case Rotax 503s) to keep up. This was a long time ago.

My point is: just because you can, doesn't mean you should. But, you are right, I was thinking only in terms of watercooled. Both the VW and 'vair are legitimate and successful aircraft conversion engines, if not ideal.
 

BBerson

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All engines have thrust bearings. The auto engine crank output stub may not be adequate for direct prop bending loads. Liquid cooled auto engines are indeed heavier than air cooled and require electric power, ECU and all sorts of parts like fuel pumps, etc.
 

litespeed

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I know its bigger and badder than you might expect but if running direct drive for a big prop and needing low rev grunt and low weight............


The first generation M70 BMW V12 is extremely light, about 30 lbs more than the normal in line BMW 6 of 2.5lt or 3lt.

A lot of weight can be saved by changing the very heavy inlet manifolds. Run it flywheel side for prop. The are huge torque engines with a very big fat gob of low down power and as smooth as any engine ever made. The flywheel can be change to a light one. If fact probably the smoothest motor made ever that runs fossil fuels.

They are 5.0 and 5.4 litre , very compact 60 V and smoother than can be believed. Simple 2 valve OHC.

You could get a easy 200hp at 2500 revs and run forever.

Any space a V8Ls motor fits will also take a V12. They are very compact and can be made a lot lighter. Things like exhaust and intake manifolds weight a heap. They have dual efi systems and redundancy standard.


The Maclaren F1 uses this engine with different heads.

Add turbo- just a big single and pick your power and revs to suit. Want 300hp at 2500 revs- no sweat. Want 400hp- no problem.

Successfully used in the Vickers Vimy replica but with redrives for the massive props.

Much better than a LS motor for aircraft, as much much smoother, harmonics are very friendly and weight is fine.

Every bit of these engines was engineered to be absolutely the best available and spent megabucks on R and D.

If you place a coin on its side on a rocker cover, and run the engine- it stays standing- that smooth.

I have seen them with way over 1000hp and they do not break.

Easy to buy for $1000.

For the Mustang replicas this is a no brainer.
 

pfarber

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Not what I said, i was mentioning to people to not make the mistake of thinking something is light, or lighter, merely based on it being all aluminium. All aluminium Honda K20's are notoriously tall and heavy for a 2.0 for example, compared to a 2.2 Toyota 5S-FE, 200cc bigger, dual balance shafts and with cast iron block is lighter.

All i am saying is take each engine on it's own merits, not what it's made from, you know, just trying to help members here to make informed choices.




Compared to what? An inline 4 is not smoother than a flat 4.

60 degree V6 engines are very smooth, yes they use a balance shaft to achieve that, but the overall weight saving is enormous over a straight 6.





"In car", a Nissan V6 weighs 320 lbs, 260 to 300+hp depending on model. Plenty of V6s out there will walk over the Vortec specs.
There are no suitable 150-200hp horizontally opposed engines in cars to convert, so the point is moot.

Inline engines will weigh less than a V, and are inlines are inherently balanced and are the smoothest running.

V-engines are heavy (need two heads, more coolant, more complex exhaust)

200hp Nissans are not practical engines to convert IMHO. They need to go up to 6000+rpm and supply costs seem to be higher.
 

mm4440

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There are flat Subarus flying in that power range. Porsches are too expensive to consider. A flat 4 has better inherent balance than an inline 4. The Suzuki G13BB is an excellent choice for a 100 hp conversion and gearboxes are available from at least two sources. Generalizations are not useful at all, real data is.
 

mm4440

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Not what I said, i was mentioning to people to not make the mistake of thinking something is light, or lighter, merely based on it being all aluminium. All aluminium Honda K20's are notoriously tall and heavy for a 2.0 for example, compared to a 2.2 Toyota 5S-FE, 200cc bigger, dual balance shafts and with cast iron block is lighter.

All i am saying is take each engine on it's own merits, not what it's made from, you know, just trying to help members here to make informed choices.




Compared to what? An inline 4 is not smoother than a flat 4.

60 degree V6 engines are very smooth, yes they use a balance shaft to achieve that, but the overall weight saving is enormous over a straight 6.





"In car", a Nissan V6 weighs 320 lbs, 260 to 300+hp depending on model. Plenty of V6s out there will walk over the Vortec specs.
60 degree V-6s do not need balance shafts; some 90 degree V-6 engines do make use of counter balance shafts.
 

pfarber

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There are flat Subarus flying in that power range. Porsches are too expensive to consider. A flat 4 has better inherent balance than an inline 4. The Suzuki G13BB is an excellent choice for a 100 hp conversion and gearboxes are available from at least two sources. Generalizations are not useful at all, real data is.
The Suzuki G13BB is not in the HP range I spoke of.

Most of the Boxer engines are not in the hp range without turbos. I (for complexity issues) don't consider a turbo'd engine as suitable.

60 degree V-6s do not need balance shafts; some 90 degree V-6 engines do make use of counter balance shafts.
A lot of motors do not need the installed. Many auto engines perform better/have higher reliability without them. Reducing vibration with a balance shaft is more for the people, not the motor.
 

aeromomentum

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Or you could just use two Suzuki G13bb engines and get 200+hp. There was a twin Suzuki Cozy that flew to Oshkosh from South America. The engines were right next to each other in the one cowling and drove coaxial contra-rotating props. Or make a semi conventional twin...
 

pfarber

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I did, an aluminium Honda K20 Vs a cast iron Toyota 5S, and only to satisfy your request, but it

WASN"T RELEVANT
,

shees, your'e command of the English language is somewhat lacking to say the least .....

Ignore list, bye bye ....
the 5S is not all iron. So your weights are off.
 

pfarber

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Direct drive automotive conversions are not really very practical. To begin with: no thrust bearing and then, crank not designed for the bending loads imposed by propeller assymetric pitch (airplane pitched) and imbalance, never mind resonance issues from aluminum props. So you have your neck stuck WAY out for crank and bearing failures. Then, the issue of RPM comes up: aspirated charge, spark ignition engines just don't work worth a **** at 2500 RPM...unless they have HUGE stroke (say up in the 5" range). Also, light engines tend to be 4 cylinder engines, and then you are DEEP into torsional resonance issues due to 180 reversals in rotational acceleration. For these reason, reduction drives are pretty much mandatory.

The ONLY way to go direct drive would be with diesel, as you can simply use turbo to make whatever manifold pressure you need to fully exploit the available mechanical strength at prop RPM, but then you still need a thrust bearing.
Most cars have a main bearing that also acts as a thrust bearing. There is even a tolerance for it. Even my 1942 Ford Go-Devil Engine had a thrust bearing.

Getting a crankshaft made with the proper strength and bearing surfaces would not be an issue. They CNC those things in a matter of hours these days.

Adding an external support bearing is also not an issue. Its been done before.

There really are NO reasons why a direct drive auto conversion can't be made. But it simply isn't in the sweep spot for most E/ABs.

Almost all E/ABs need 100-180hp. That covers about 90% of the market. A suitable direct drive motor would require a V8 and those are just to heavy at the 100-180hp range. Above 200hp they become a good second choice.
 
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