33-40 hp 4 stroke engine ?

Discussion in 'Firewall Forward / Props / Fuel system' started by BenoitLescot, Feb 13, 2010.

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  1. Feb 13, 2010 #1

    BenoitLescot

    BenoitLescot

    BenoitLescot

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    hi there,

    I am looking for a light engine between 33 and 40 hp, I'm not too found of two strokes engines as they seem to have tendency to seize and they need premixed gas/oil, also not too sure if they could wistand 3 hour flights @5000ft.
    My design is of the multi-engine kind, thus when dividing power required by number of engines I come up with 33hp min and I have set a max to 40hp (max continuous)
    I looked at the rotary engine, it looks very promising but I haven't found a 40hp version yet..
    hope somebody can shed some light in !
     
  2. Feb 13, 2010 #2

    Jan Carlsson

    Jan Carlsson

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  3. Feb 13, 2010 #3

    Joe Kidd

    Joe Kidd

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    Sound's like you need to consider a 1/2 VW engine, the half case version weighs the least but cost's a bit more. Great Planes and Hummel Engines have these. Hummel engines offers a 40HP with lightweight cylinders...
     
  4. Feb 14, 2010 #4

    BenoitLescot

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    Thks, the 1/2 vw engine looks good, will be too wide for my design so it would have to stick out.. Checking the rotating..
     
  5. Feb 14, 2010 #5

    litespeed

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    Old style two strokes tend towards unreliable- but their are alternatives to this in the newer style water cooled two strokes, high power, good economy and with water cooling the engine temps are very constant and removes much of the potential to seize- no shock cooling or overheating. I would expect one of these to be quite capable of long range and success over long flights.

    Simmonini make excellent engines and are light, powerful and reliable. They come with a good belted PSRU and are not overstressed.The average fours stroke of 40hp is very heavy.
     
  6. Feb 14, 2010 #6

    Joe Kidd

    Joe Kidd

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    Another 4 stroke option is this one from Valley Engineering
    Valley Engineering - Big Twin

    It's a commercial engine which can be purchased elsewhere and then modified, other redrive options are also avaliable...
     
  7. Feb 14, 2010 #7

    BenoitLescot

    BenoitLescot

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    thanks all for your input, I've come across most of these, one last negative point for me (if you consider the water cooled 2 stroke being less prone to seizing) is to have to do your mixture fuel oil, is there any way this can be done transparently ? by a mixer ? how reliable would that be ? If I land somewhere and park at the pump I want it to be easy ;)
     
  8. Feb 14, 2010 #8

    BenoitLescot

    BenoitLescot

    BenoitLescot

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    wow kart engines, I found this engine, 250cc monocylinder 4 strokes 55lbs :
    Swissauto_250_Home

    but running at 10.000 rpm ? don't think that's a good idea maybe not for 3 hours either, anybody had experiences with such engines ?
     
  9. Feb 14, 2010 #9

    Dana

    Dana

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    Many of the newer Rotax 2-strokes have oil injection, so you don't have to mix your fuel and oil, just keep the oil tank full. Not only does it eliminate having to mix the oil, it adjusts the amount of oil based on throttle setting so less oil is used at lower throttle settings, where it doesn't need as much. This reduces spark plug fouling. Modern 2-strokes are actually quite reliable if they're jetted correctly.

    -Dana

    If at first you DO succeed, try not to look astonished!
     
  10. Feb 18, 2010 #10

    BobbyZ

    BobbyZ

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    the design is based on the newest 4 stroke motocross tech,not something I'd recomend for A/C use.Reliability has been a big issue as of late in the mx bikes,Many guys are wishing to have their 2 strokes back ;) The massive bore to stroke ratio leads to a piston with virtually no skirt for stability or longevity.

    dana is right about the new 2 strokes,While I have no experience with A/C 2 strokes I do have 15 years in racing 2 stroke mx and cross country bikes and another 5 years managing a factory supported MX team.There are 2 things to making a 2 stroke live a long healthy life........Jetting is key,I cant say this enough !Our race bikes where jetted within a mm of their life,changes from morning to afternoon,heat to heat.The other killer is chopping the throttle after a long high rpm run,in doing so you eliminate the lubrication to the engine when it needs it most........not good.I would imagine this alone has killed many of the ealrier A/C 2 strokes.The rotax engines mentioned by Dana with oil injection all but eliminate this problem.......with proper jetting and use I would not hesitate to get in a A/C with a 2 stroke.
     
    Last edited: Feb 18, 2010
  11. Mar 11, 2010 #11

    jack404

    jack404

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    G'day

    I've found one of the most reliable motors about is a Ural Moto

    its a russian copy of the 1938 BMW motor but simplified with modern carbs that will feed reliably up to and including 90 deg

    these put out a reliable 38HP at 3800 RPM 42 HP at 4200 RPM and on my first build suited my plane perfectly

    these are cheap , reliablke and now come with a electric start ( my old one was kick start and magneto only)

    i'm building the affordaplane this time and putting a new engine on it with full electrics

    i personally dont like/trust 2 stokes and this engine is as solid as any i have seen

    cheers all

    jack
     
  12. Mar 11, 2010 #12

    Cazador

    Cazador

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    [​IMG]
     
  13. Mar 11, 2010 #13

    Joe Kidd

    Joe Kidd

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    Somehow the concept of kick starting an airplane engine doesn't appear to be very logical...just saying...{;0)]=
     
  14. Mar 11, 2010 #14

    Cy V

    Cy V

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    He did say it came with electric start now.....so I'm sure kick starting your airplane won't be an issue. ;)
     
  15. Mar 11, 2010 #15

    jack404

    jack404

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    hey i did it for two years and i never used my foot ..

    yank hard on the lever and it started every time

    but yes the electric start has much more appeal

    great pic by the way , the ones i have are nowhere near as good

    now leave off the gear box ( save that weight)
    make up a mounting plate of T6 Alu.
    mount the electric start

    and you have a great little lightweight motor thats as reliable as they come

    i dunno cost in the US, but here in Australia the engine is $4600 brand new pretty much as pictured ( some electrical wires and stuff included)

    cheers

    jack
     
  16. Oct 19, 2010 #16

    cmm

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  17. May 10, 2011 #17

    Cazador

    Cazador

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    [FONT=Verdana, Arial, Helvetica, sans-serif]THE SAVOIA S42Aero AIRCRAFT ENGINE[/FONT]​

    [​IMG]
    [FONT=Verdana, Arial, Helvetica, sans-serif]• Twin boxer, 4 stroke, air cooling forced by fan, plus a separated oil cooler with thermostat.
    [/FONT][FONT=Verdana, Arial, Helvetica, sans-serif]• 652 cc displacement, 9.5:1 compression
    [/FONT][FONT=Verdana, Arial, Helvetica, sans-serif]• Fuel injection and double ignition with 2 prog ECU. With altimetric mixture compensation.
    [/FONT][FONT=Verdana, Arial, Helvetica, sans-serif]• 12V electric start and 10A PMG alternator
    [/FONT][FONT=Verdana, Arial, Helvetica, sans-serif]• Max Power: 42 HP (30 kw) at 6000 rpm
    [/FONT][FONT=Verdana, Arial, Helvetica, sans-serif]• Torque 55 Nm from 4000 to 5000 rpm
    [/FONT][FONT=Verdana, Arial, Helvetica, sans-serif]• 95 octane gasoline consumption (min.):200 g/kw.h
    [/FONT][FONT=Verdana, Arial, Helvetica, sans-serif]• Pulley & belt gear with tensor, CCW turning, 2.043 – 2.65 - 3:1 relationship
    [/FONT][FONT=Verdana, Arial, Helvetica, sans-serif]• Total weight: 48-50 kg
    [/FONT][FONT=Verdana, Arial, Helvetica, sans-serif]• 500 h TBO [/FONT]​


    motores_aero_foto_real_001.jpg motores_aero_foto_real_002.jpg


    [​IMG]
     
    Last edited by a moderator: Mar 20, 2019
  18. May 10, 2011 #18

    Dana

    Dana

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    Hmmm. 110 lbs and 1.76gph at 80% compared to 80 lbs and 3.5gph for a 2-stroke. Total weight the same with a 5 gallon tank for the 4-stroke vs a 10 gallon tank for the 2-stroke, and equal range. Seems to make sense on anything but an ultralight that's hard up against the 254# limit.

    I wonder what it costs?

    -Dana

    I don't like the idea of term limits for politicians. I think they should get the same sentence as all other criminals.
     

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