Suzuki Motorbike engines

Discussion in 'GEO / Suzuki' started by divad_strebor, Jun 12, 2008.

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  1. Jun 12, 2008 #1

    divad_strebor

    divad_strebor

    divad_strebor

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    Has anyone looked into converting motorbike engines for aircraft use? I have a handfull of suzuki's in my shed, including a 1985 GSX 1100. I was looking at this motor the other day, and I don't think it would be too difficult to mount the top end and the crank onto a custom crankcase with a belt reduction drive (or similar)

    Specs from memory are:

    1135cc aircooled DOHC 16 valve.
    118PS @flywheel @ 11,000ish (I've been told PS equates almost exactly to BHP)
    Weight, I don't know... I can lift it off the floor, but need a helper to get it onto my workbench. But thats with the gearbox. I think the head weighs a bit though...

    Its just a thought that I've had... I have no intention of butchering this engine (nor any others that I have in my shed at the moment) but if its feasable it may be an option for future reference. There are more modern engines around that produce MUCH more power in a lighter package, but these are usually liquid cooled, which means more things to go wrong IMO...
     
  2. Jun 12, 2008 #2

    river1

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    Try yahoo groups moto-air .
     
  3. Jun 12, 2008 #3

    Dana

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    I know nothing about larger bike engines, but I converted a Kawasaki KX100 engine for PPG use. Rather than making a new crankcase (though I'm still tempted to trim the case, to save weight, if I ever find the time). To save the trouble of building a redrive, I kept the entire gearcase (with most of the gears removed, of course!) and drove my propeller off the original 3.4:1 primary reduction gearing that normally drives the clutch. I made a new prop shaft and support bearing asembly that mounts to the engine where the clutch cover used to be, with the original driven gear (that was part of the clutch assembly) mounted, with the original rubber torsional dampeners, to the prop shaft.

    -Dana

    When you get it right
    mighty beasts float up into the sky
    When you get it wrong
    people die

    -Roger Bacon (c1384)
     
  4. Jun 12, 2008 #4

    Joe Kidd

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    This is a really great question. The Suzuki/Geo engine is used with the Raven Redrive, I've read and seen where the M/C engines have been used in homebuilt off road 4-wheel vehicle's with good effect. So given that what would limit there use in the correctly sized airframe, as mentioned by Dana? I love learning about this stuff from you folk's.

    JK
     
  5. Jun 13, 2008 #5

    WurlyBird

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    And this brings up a question my friends and I have discussed before; What if you keep the tranny attached and operational? Theoretically you could shift gears to spin the prop at different speeds. Low gear for take off, high gear for cruise. It would probably work best with only a few real close gears and then would the weight offset any performance gains?
     
  6. Jun 13, 2008 #6

    orion

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    Shifting gears does absolutely nothing for you in flight unless you also plan to substantially modify the prop geometry as you fly (in chord, diameter and twist). The physics of propeller propulsion and flight don't work the same way as gears and the physics of driving.

    The other problem is the issue of weight - the mass of the substantially large transmission case, not to mention all the gears, shafts and clutch components, would make the power-to-weight efficiency downright awful.

    But that's not to say it hasn't been done, at least in a limited form. There's an outfit up in Canada that uses a LS-1 (or -6?) with tranny for retrofitting Spencer Amphibs and some years back I saw someone use a Honda Goldwing engine and its transmission case to hook up to a remotely supported prop. In both cases the clutches or torque converters are removed, as are all the extraneous components. Only one ratio is maintained, which delivers the necessary torque and rpm performance.
     
  7. Jun 13, 2008 #7

    divad_strebor

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    Here is an exploded view of the motor I have. As you can see, the clutch drives from a gear on the crank between #s 3 and 4 cylinders. You COULD use the clutch basket gear as is in its original location, but this would mean the cylinders would be offset from the propshaft. I was looking at the engine thinking you could sling the propshaft "underneath" with a custom housing and/or crankcase (incorporating thrust bearings), make up a dry sump lubrication system, flip the whole thing upside down, and BINGO! You have a miniture Gypsie Major! Perfect for those 80% fisher tigers... or make 2 of them and build a scaled down DH Comet! How cool would that be?!

    The only thing is you'd have to make a manifold for the carbies to put them somewhere else for it to fit into a DH style cowl. This would have an adverse affect on the power output I think.

    About the shifting gear thing, all it will change is Prop RPM. Low gear=high engine RPM=low prop RPM=low thrust. The engine won't be straining to turn the prop, but the prop won't be doing much. High gear=engine struggling to push=high torque=potential to be down on prop rpm (worst case scenario). Your better off setting up the reduction ratio vs prop dia/pitch to produce peak prop thrust (rpm) at peak power RPM on the engine. If that makes sense.

    I went to have a look at the moto-air yahoo group, but you need to be signed up to yahoo. I used to be years ago, and tried that account, which worked... but it sent my activation email to an address that no longer exists. I gave up.
     

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  8. Jun 13, 2008 #8

    bmcj

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    I disagree Orion (with a caveat). I've often toyed with the thought of building a twin prop airplane using a VW engine and transaxle. I agree it would do absolutely nothing for performance... I just wanted to see people's reaction when they heard a plane shifting up throgh the gears! :gig:
     
  9. Jun 13, 2008 #9

    Joe Kidd

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    Divad,

    I'll try to sighn up for one of the Yahoo motor air group's this weekend to see if they have any good information. Also you can alway's just sighn up for a new Yahoo account, I've done that in the past myself.

    bmcj, I have to agree hearing an aircraft go changing gears would make a lot of people stop and stare.

    CW
     
  10. Jun 15, 2008 #10

    WurlyBird

    WurlyBird

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    The transmission idea was one that I originally read of in Kitplanes magazine back in the early 90s. I believe the idea was more geared towards lighter aircraft such as ultralights. I think the idea was meant for "underpowered" planes that needed very long take off runs due to the engine not being able to spin the prop fast enough to develop much static thrust. Lower gear, more torque to create more static thrust. I have never been all that good at prop dynamics and you are probably completely correct, but on a simple level it seems to make sense.
     
  11. Jun 15, 2008 #11

    orion

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    True, small diameter props, such as are required when you're designing for a high rpm application, do not do as well as a large diameter prop spinning slower. But the props are very specific designs configured precisely for the rpm and anticipated speed. If you turn it any slower or faster than what it is designed for, its performance will suffer significantly. For this reason ideas like changing gears mid-flight don't work. A much better approach is the constant speed configuration where the pitch angle of the blades is changed as a function of speed and engine torque.
     
  12. Apr 20, 2009 #12

    Hetzer

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    There is at least one company that works with the older Suzuki engines in France. They look very expensive however and you would be dealing with an overseas, and small, company.

    Produits

    There is another company in the US working on making a 1300cc Hayabusa motor that has had the transmission deleted. This looks promising to me, depending on what the price of the conversion kit ends up being.

    H2 Busa
     
  13. Apr 21, 2009 #13

    Joe Kidd

    Joe Kidd

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    "There is another company in the US working on making a 1300cc Hayabusa motor that has had the transmission deleted. This looks promising to me, depending on what the price of the conversion kit ends up being.

    H2 Busa "

    That's an awfully large amount of HP vs weight Hertzer. I wonder what type of redrive would be needed to match up to it, not to mention how you'd balance the entire combination for use in an airframe without shaking itself to bits.
     
  14. Apr 22, 2009 #14

    Hetzer

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    I was wondering about that h2 busa myself, it is "basically" the same motor that the French company has flying, without the transmission. The French company rates it at 100 to 120 HP depending on the displacement used at around 7000RPM. The French company uses the older Suzuki motor which is all oil cooled, no water radiator just a large oil cooler. My worries are about detonation, those motors are high compression, and over revving the prop. I would think that if a motor that is capable of 12000RPM is carrying such a load that it can only spin 7000RPM you would have to decrease the compression a lot, factory bikes are around 12.5 to 1, IIRC. The other side of the problem might be what happens if it can still spin say 9000RPM? What kind of gearing would that require? Would it still be safe/reliable?

    Just my ramblings
    Thanks
     
  15. Apr 27, 2009 #15

    Hetzer

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  16. May 4, 2009 #16

    Erwin

    Erwin

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    In belgium (country I live) the conversion of a 650 cc V-Twin Suzuki has already been made to fly a ultralight Calypso (also made in Belgium) See the link
    There is even a short film at this site. It has even the clutch working and the dashboard from the bike is in use at the plane. Nicely made...
    Greetz, Erwin
     
  17. May 5, 2009 #17

    Hetzer

    Hetzer

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    Erwin,
    Do you know how many hours it has flown? I have heard that the transmission in motorcycle engine tend to fail in the extreme aviation environment.
    Thx
     
  18. May 6, 2009 #18

    Erwin

    Erwin

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    Never had contact with the builder, but you can try and contact him at (mitchie "@" skynet.be)
    Also know some Calypso's flying with a Citro├źn Visa engine (twin boxer)
    G. Erwin
     
  19. Nov 4, 2009 #19

    bmcj

    bmcj

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    I tend to agree with Orion, but found this on a Franklin Motors Aeroengines website and thought it was interesting. Pay particular attention to the third sentence:

    Bruce :)
     
  20. Nov 4, 2009 #20

    BBerson

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    My old Helicopter Engineering book says a two speed transmission would be optimal in theory for a helicopter. It is desirable to us a low tip speed for hover and a higher tip speed to avoid blade stall at high cruise speeds.
    But this has not proved to be worth the extra machinery as far as I know.

    Actually some modern helicopters (Eurocopter) have chosen to slow the tip speed a bit in cruise to limit noise.

    I doubt that a two speed drive for a prop would be worth the trouble.
     

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