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Thread: Converting Auto Engines

  1. #21
    Gunslinger37's Avatar
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    Early Rotorway helicopters used a converted outboard motor. And remember, the Rotax started life as a snowmobile powerplant.

  2. #22
    Quote Originally Posted by Aaron Novak View Post
    Personally Id like to see something like a Merc 9.0 litre tuned to deliver around 900 HP and stripped down weight wise. At least it is one of the few engines designed for a similiar duty cycle as an aircraft engine, and would probably be a much better package than an over stressed automotive engine. Should be more than competitive with a falconer V12 and a heck of a lot more reliable due to a better valvetrain for the speeds they run.
    http://www.mercuryracing.com/sterndr...ngines/1100-2/
    The thing about the "more is better" is that it doesn't always work with airplanes. If you read about Ben Haas's experience with having too much power....ergo:" for every action there is an equal and opposite reaction" you will see that you have to be careful what you wish for. The thing about redrives is they often induce additional reliability problems into the equation. They definitely add weight and cost. For some reason it has kinda become the "norm" that when using a larger auto engine like an LS Chevy that one "must" adapt the propeller with a reduction drive. The scenario generally tends to be "I'll buy an LS1 crate motor" then use the reduction drive to use all that 350 hp. First, many airplanes can't use that much power.....especially when you already have maneuvered into a problem attitude.

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    Lycoming got it right with simple direct drive. If someone wants to use an LS, my opinion is that they would be better off either buying a larger displacement LS3 crate engine, or better yet....build or buy a purpose built larger displacement LS engine. There are lots of companies selling quality built 408 and 416 and even 427 shortblocks for reasonable prices. Since the engine would be direct drive, one would expect that rpms would be maybe 3600 or less. That means a smaller propeller, but the additional hp gives room to play with pitch and efficiency. The point here is that by using an engine that weighs the same as the smaller displacement LS1 (346 cu in) but has more capacity (416 cu in), you can develop a very easy 250 hp and probably quite a bit more. After the shortblock is assembled, dirt cheap LS1 heads and intake can be used because you only need something that provides good airflow at 3600 rpms. You don't need the more expensive higher flowing stuff. You can even put a different intake manifold on it and use a carburetor if you like. What you WILL have to do is make some simple direct drive setup to bolt a short drive shaft and support bearing in place. That will cost way less than a redrive, and weigh less too. Often, excessive weight prevents a good conversion no matter how much hp you have. The direct drive should make the airplane lighter overall and especially lighter on the nose. Don't believe that excessive hp is the best answer unless you are building a racing airplane. It would help a lot if you were to tell us what kind of airplane(s) you are considering.

    Also, the idea that auto engines aren't designed for continuous high rpm use is a myth. Just about any auto engine built today undergoes way more rigorous testing than any aero engine ever has. Chevy has high speed tested LS engines for months on end. Ford does the same too. Look at this video produced by Ford and be amazed as I was.


    https://www.youtube.com/watch?v=G-DsrC57UD8
    Last edited by ekimneirbo; 09-07-2016 at 09:25 AM.

  3. #23
    Aaron Novak's Avatar
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    Quote Originally Posted by ekimneirbo View Post

    Also, the idea that auto engines aren't designed for continuous high rpm use is a myth. Just about any auto engine built today undergoes way more rigorous testing than any aero engine ever has. Chevy has high speed tested LS engines for months on end. Ford does the same too. Look at this video produced by Ford and be amazed as I was.


    https://www.youtube.com/watch?v=G-DsrC57UD8
    Thats just advertising bullplop. None of the ford modular or current engines are designed for WOT operation, same goes for the LS series. Unfortunately some of the issues cant be fixed swapping parts. They are great for what they were designed for though. I should add that I work in the engine industry and work with engineers from both companies so I have some insight that most dont. As for application for the 900hp engine, I was thinking along the lines of a 3/4 P-51 51 or anything designed for an orenda V-8, and yes probably more for racing.

  4. #24

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    Quote Originally Posted by Aaron Novak View Post
    Thats just advertising bullplop. None of the ford modular or current engines are designed for WOT operation, same goes for the LS series.
    Hi Aaron,
    The validation testing done by most automotive engine manufacturers exceeds the requirements that the FAA places on a typical Lycoming, for example, based on the various postings we have seen over the years. The FAA only requires 100 hours of full throttle, full rpm for certified engines and another 50 hours at 75-100% power, 50 hours of which are required to be at redline oil and cylinder head temperatures. Most auto engine manufacturers today do a minimum validation of 200 hours of WOT at rated hp rpm and some as much as 1200 hours. This doesn't appear to be "advertising bullplop", but rather a way to ensure a lack of warranty repairs and recalls to save money in the long term.

    In other words, the automotive engine is just as suitable (if not more so) to run at WOT as a typical Lycoming according to the validation testing. The other thing to consider is that when flying, most people typically aren't at redline RPMS during cruise flight, much the same as when flying a Lycoming.

    The idea that auto engines aren't suitable for continuous high rpm use is a myth.

    -Dj

  5. #25

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    Quote Originally Posted by ekimneirbo View Post
    ...If someone wants to use an LS, my opinion is that they would be better off either buying a larger displacement LS3 crate engine, or better yet....build or buy a purpose built larger displacement LS engine. There are lots of companies selling quality built 408 and 416 and even 427 shortblocks for reasonable prices. Since the engine would be direct drive, one would expect that rpms would be maybe 3600 or less....What you WILL have to do is make some simple direct drive setup to bolt a short drive shaft and support bearing in place....
    I got "laughed at" once for posting the info about my old Dodge truck 318ci horsepower vs Lyc O-320 horsepower. The truck engine was rated at 165hp and everybody jumped about how they knew 318's will put out 95 gazillion not just 165. Yet the fact was, the factory rated that engine in that vehicle at 165hp turning 2400 rpm because it was optimized to be a truck engine moving the design weight with the design transmission and specified rear axle ratio. It was a system, not a crate full of possibilities. 2000 rpm torque peak gave 65 mph cruise, with a kickdown from overdrive to climb small grades at 2400 rpm horsepower peak without dropping off 65 mph. So if one looked for a great no-reduction-drive propeller turner, there she was, about the same power as an O-320 at about the same rpm. Oh, a bit more weight, and you gotta start running vibration harmonic tests to avoid eating your crankshaft or tossing a prop blade, but hey, simplicity and cheap compared to a Lyconsaurus and by golly they run on forever. Radiator? Water pump? Pffft.

    Design involves compromises, which will best meet your needs?

  6. #26

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    Ok guys, so it has been a few years and I still have not seen many big auto engine conversions at OSH. I would love to know who, where to see them, there don't seem to be many in Minneapolis. I have a subscription to Contact! There is good info there, but not enough. I have been doing my research and it will cost a pretty penny to build the motor I am thinking of.

    Here is the dream. The reason I am looney. Aaron, you mentioned a 3/4 P-51. I am not a fan of scale. I am going for a the look, sound and aura of a real warbird without the million dollar price tag, I think it is important for people to see just how big and beautiful these planes are. So yes, all along the beginning reason for the question was to see about using 2 Nissan VQ35DE engines. Talking to the tractor pull folks, they do not have issues with failure of the engine at the coupling, so that concern will be put to rest. I can build the motors to run at 900bhp each at 6600RPM and get low end torque in the 3000 to 3500 RPM range of about 300bhp each. That will get me about 600hp at 3400rpm.

    As for direct drive versus PSRU. I am building a replica as close as possible and the P-51 used a PSRU. The prop spins at 1750rpm, while the Merlin turns at 2800-3400rpm. So for 70 years the technology has been around and we have all enjoyed seeing the magnificent beasts in the air. When you have the extra HP, we can use a PSRU not problem. (yes it adds complexity) PSRU's are not the problem, the lack of engineering behind many of them has been.

    So here is where I can add more complexity. How about a 2 speed PSRU. One to make the sound correct and tool around with 600hp. Then kick in the other gear ratio and let the baby run. I still wouldn't do WOT as that would be asking for trouble. But getting up to 4000-4500 rpm might produce some speed.

    So once I get my gofundme page running to build the 100k motor, then I will know. Otherwise an Allison might be in my future. I still like the idea of experimenting with the Nissan motor. It is interesting to compare it to a Merlin. As a NA Merlin produces 600hp, 2 VQ's NA do the same. They are both 60 degree V's with similar horsepower to weight ratio's. It would be odd powering an American classic with a Jap powered motor, but the VQ is made in Deckerd, TN. Besides the Merlin is a foreign engine as well.

    Thanks for all the great comments. Keep them coming. Maybe one day i will be able to show off my plane at OSH.

  7. #27
    Quote Originally Posted by Aaron Novak View Post
    Thats just advertising bullplop. None of the ford modular or current engines are designed for WOT operation, same goes for the LS series. Unfortunately some of the issues cant be fixed swapping parts. They are great for what they were designed for though. I should add that I work in the engine industry and work with engineers from both companies so I have some insight that most dont. As for application for the 900hp engine, I was thinking along the lines of a 3/4 P-51 51 or anything designed for an orenda V-8, and yes probably more for racing.
    Auto engines are designed to perform under the most arduous conditions. You say they are not designed for continuous WOT operation. If you check the testing done by the aviation industry, you will find it doesn't compare with what an auto engine is subjected to. The LS (Chevy) engines were run WOT for months on end and were only stopped when the facility had to be used for some other scheduled tests.
    They ran not just one or two engines, but a whole bunch (30 ? memory ?) and not one failed.

    Now, about the loosely bandied term WOT. In many airplane engines the term WOT refers to about 2700 rpms. This really isn't correct terminology as the engines will turn more than 2700 rpms, and produce more hp. They also will develop a shortened TBO and often other problems arise that require repairs before TBO. The 2700 is established because that is where the propellor tip speed begins to approach the speed of sound and become noisy and inefficient. I think thats also where many of them reach peak torque. So, while the throttle is often mechanically capable of letting the engine exceed 2700 rpms, most pilots refer to 2700 as being WOT. An auto engine operated in direct drive will operate normally at 3600 rpms or less and use a reduced length prop blade to keep tip speed down. Again, that is no where near WOT for any auto engine I can think of...and that includes everything from VWs to Big Block Chevys. Add a reduction drive and most of the auto engines still are set up to operate well below WOT with something like 4500/5000 often being used. Generally the higher rpms are in the smaller engines, but none of them even begin to approach WOT and at the 3600 rpm level they are virtually loafing. The reliability of todays auto engines is better than aircraft engines. In order to have a reliable aero engine, you have to fly it regularly, and have a costly inspection EVERY year. If you maintain it properly it will be reliable.....but expensive. Clapped out used aero engines are often confused with the reliability established by brand new or zero timed engines from the factory. When they have no records and are no longer certified, they become a different entity thats riding the coat tails of the new engines.
    If an auto engine had to go to the dealer every year for inspection and often repairs, it would be considered a "lemon". When is the last time you even bothered to put spark plugs in an auto engine ? My Chevy truck is approaching 100K so I decided to change the oil and put new plugs in even though it was still running just fine.

    Auto engines are used to run pumps across Texas and they run continuously for years with little or no maintaince.

    Reliability of auto engines is not a problem. The problem is that whenever an airplane containing an auto engine crashes irresponsible comments often cast aspersions on the engine. Just the other day a fellow who is building a factory assisted high dollar airplane with a Chevy engine said (on another website) that the company didn't support builders who opted to use engine "M" in their kit. He further stated that two of the airplanes utilizing engine "M" had crashed. Pretty damaging to engine "M"s reputation. When quiried about the cause of the crash, he said he didn't know any details and had no idea if the engines failed. All of this came about because an 80 (85 ?) year old pilot had crashed a third "M" powered airplane. The crash was just after leaving the tarmac when one would expect that the pilot could have just landed again. The pilot was well known and had flown many hours in the plane. Given the sketchy details available, it seemed highly unlikely that the engine failed, but it did quit. Most likely were a health trauma or fuel issue since the engine had barely gotten past warm up stage.
    Yet, the propagated story was that an "M" powered airplane crashed. Sadly, these kinds of irresponsible comments is what prevents many conversions from becoming successful...just like the myth on reliability.
    Last edited by ekimneirbo; 11-23-2016 at 10:37 AM.

  8. #28

    Ford 300 IL 6

    Quote Originally Posted by ekimneirbo View Post
    Auto engines are designed to perform under the most arduous conditions. You say they are not designed for continuous WOT operation. If you check the testing done by the aviation industry, you will find it doesn't compare with what an auto engine is subjected to. The LS (Chevy) engines were run WOT for months on end and were only stopped when the facility had to be used for some other scheduled tests.
    They ran not just one or two engines, but a whole bunch (30 ? memory ?) and not one failed.

    Now, about the loosely bandied term WOT. In many airplane engines the term WOT refers to about 2700 rpms. This really isn't correct terminology as the engines will turn more than 2700 rpms, and produce more hp. They also will develop a shortened TBO and often other problems arise that require repairs before TBO. The 2700 is established because that is where the propellor tip speed begins to approach the speed of sound and become noisy and inefficient. I think thats also where many of them reach peak torque. So, while the throttle is often mechanically capable of letting the engine exceed 2700 rpms, most pilots refer to 2700 as being WOT. An auto engine operated in direct drive will operate normally at 3600 rpms or less and use a reduced length prop blade to keep tip speed down. Again, that is no where near WOT for any auto engine I can think of...and that includes everything from VWs to Big Block Chevys. Add a reduction drive and most of the auto engines still are set up to operate well below WOT with something like 4500/5000 often being used. Generally the higher rpms are in the smaller engines, but none of them even begin to approach WOT and at the 3600 rpm level they are virtually loafing. The reliability of todays auto engines is better than aircraft engines. In order to have a reliable aero engine, you have to fly it regularly, and have a costly inspection EVERY year. If you maintain it properly it will be reliable.....but expensive. Clapped out used aero engines are often confused with the reliability established by brand new or zero timed engines from the factory. When they have no records and are no longer certified, they become a different entity thats riding the coat tails of the new engines.
    If an auto engine had to go to the dealer every year for inspection and often repairs, it would be considered a "lemon". When is the last time you even bothered to put spark plugs in an auto engine ? My Chevy truck is approaching 100K so I decided to change the oil and put new plugs in even though it was still running just fine.

    Auto engines are used to run pumps across Texas and they run continuously for years with little or no maintaince.

    Reliability of auto engines is not a problem. The problem is that whenever an airplane containing an auto engine crashes irresponsible comments often cast aspersions on the engine. Just the other day a fellow who is building a factory assisted high dollar airplane with a Chevy engine said (on another website) that the company didn't support builders who opted to use engine "M" in their kit. He further stated that two of the airplanes utilizing engine "M" had crashed. Pretty damaging to engine "M"s reputation. When quiried about the cause of the crash, he said he didn't know any details and had no idea if the engines failed. All of this came about because an 80 (85 ?) year old pilot had crashed a third "M" powered airplane. The crash was just after leaving the tarmac when one would expect that the pilot could have just landed again. The pilot was well known and had flown many hours in the plane. Given the sketchy details available, it seemed highly unlikely that the engine failed, but it did quit. Most likely were a health trauma or fuel issue since the engine had barely gotten past warm up stage.
    Yet, the propagated story was that an "M" powered airplane crashed. Sadly, these kinds of irresponsible comments is what prevents many conversions from becoming successful...just like the myth on reliability.
    Hello everyone. I am new here. I enjoyed the discussion immensely as I am building a WW I German Fokker D VII and will be using a 1979 Ford IL 6 300 with a redrive. This engine combination will be swinging a 108" propeller at roughly 1400 RPM. This engine, versus the BMW or Mercedes used in 1917, will put out just under 200 hp at a 200 lb weight reduction. I will be using an alternator, starter, and full sized car battery along with the redrive to offset the weight difference. Everything else will be as close to original as possible. Oh, I will swap out the old Ford single barrel carb for an Offenhouser 4 barrel set up.

    These old Ford 300 engines have the bench mark for the term bullet proof. They were used in dump trucks, Good Humor trucks, UPS vans, pumps, ramp vehicles etc and were designed to run all day between 3000 and 4000 RPM. I rebuilt one of these 35 years ago and the car crumbled around the running engine. I will take that over a $40,000 Lycosaur any day.

    Jim

  9. #29

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    good afternoon!
    tell me please, and what kind of conversions on in-line engines do you use on airplanes?
    on our first plane, we lived on the side of Honda Fit, but then came to the conclusion that it was laborious and began developing a belt reducer for the in-line engine ...
    https://www.youtube.com/watch?v=ZKbRX9vO1VM&app=desktop
    https://www.youtube.com/watch?v=hCgv7V7fzuw&app=desktop
    Yours faithfully, Vadim .

  10. #30

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    On the first plane we put the Honda Fit 1.5. We have the gearbox was a small distance between the axles,and we had to put the motor on its side, thus we have the ability to hide the beautiful motor hood. Here's how it looks.......
    Attached Images Attached Images    

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