What engine would YOU build

Discussion in 'General Auto Conversion Discussion' started by Winginitt, May 15, 2019.

  1. May 16, 2019 #41

    wsimpso1

    wsimpso1

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    Harruph! Your rules are too restrictive.

    I suspect that the ideal engine in the 200 hp class is a three cylinder opposed piston two stroke diesel. Yeah, three cylinder, six pistons, two crankshafts, big gear train as an integral speed reducer, inherently balanced, water cooled, no valve gear. Gemini currently has a 100 hp, compact, reasonable weight, very fuel efficient. Roots blower for starting and low power operation, turbocharged for full power. Busts all of your rules, but makes a great engine. Now if they built one at 180-200 hp...

    Billski
     
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  2. May 16, 2019 #42

    Hephaestus

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    I'd do a new take on Mr wittmans aluminum 215 olds v8 ;)
     
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  3. May 16, 2019 #43

    Hot Wings

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    Completely forgot about this fuel option. :oops: For a clean sheet engine design it's probably the best choice.
     
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  4. May 16, 2019 #44

    TarDevil

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    I was very impressed with that engine and struggling to figure out why it hasn't gained traction.
     
  5. May 16, 2019 #45

    pictsidhe

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    Your scheme is not grand enough. Go for the triple crank Deltic version, with 2 pistons per crank throw instead of 1.
    If you don't want all the cylinders needed for an even fire Deltic, a 'Rhombic" could be another option.
     
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  6. May 16, 2019 #46

    revkev6

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    yup, pretty sure that was it. claimed 100hp at 2900rpm... couple things that may be a little sketchy on that one though....
    they have that thing bumped out to 175cubes. huge vw engine.

    their mag case (which is actually aluminum in the pictures they show, very different color) with a whopping 94mm stroke crank made with prop flange and a 97mm bore.. which is a very odd bore size for a vw. I'm guessing they are using 5.3l LS pistons in it?? sbc rods are common on vw crankshafts for clearance on stroker engines and they are very similar to the longer LS rods. ... would be interesting to see what is inside. unfortunately due to the combined use of all the aftermarket parts I'm not seeing this as a "cheapish" upgraded vw but more like a specific aircraft engine like a jaburi or a rotax.... there will be nothing vw left in that engine. maybe a camshaft...
     
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  7. May 16, 2019 #47

    spaschke

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    A turbine APU supplying electric power to multiple electric motor and props. Similar to the X-57 but lower power.
    The marine 2 stroke diesel motors would also make a good lightweight APU.

    Steve
     
  8. May 16, 2019 #48

    stratocruiser

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    I think it means that a larger prop can be driven at a slower RPM which is more efficient. Therefore, more thrust for the same amount of power or looking at it another way, the same thrust with less power and therefore less fuel consumption. Either way it is more efficient, even if a gearbox or belt reduction will add weight and complication. It will also absorb a little power too but should result in a net gain in efficiency.
     
  9. May 16, 2019 #49

    wsimpso1

    wsimpso1

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    LOL!
     
  10. May 17, 2019 #50

    Dana

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    Scat made aviation specific heads for Mosler's VW and half VW engines. Similar to the heads Scat still sells to the dune buggy guys, but with the intake on the bottom. Problem is you need a significant volume to tool up for something like that (Scat heads were cast) or go machined billet, which is expensive.
     
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  11. May 17, 2019 #51

    proppastie

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    Clean sheet computer controlled 2 stroke. ....properly designed direct drive at normal prop speeds.
     
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  12. May 17, 2019 #52

    pictsidhe

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    Well, if we're building engines from scratch, maybe I should tell you about another of my daydreams

    103 sized turbofan, for the me262 I'd like to build in a few planes time.
    Gas generator is two compounded turbos. a Garret GT06 is aboutt right for the top turbo, a mash up of MHI bits for the bottom turbo. The power turbine is simply jets in the tips of the ducted fan blades. That means a hollow stainless ducted fan, which is the where most of the construction fun will lie.
     
  13. May 17, 2019 #53

    pictsidhe

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    How many cylinders?
     
  14. May 17, 2019 #54

    mm4440

    mm4440

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    Water injection, without any alcohol is not technically a power adder. It does allow a higher CR.
    A Mazda rotary with a PSRU will work.
     
  15. May 17, 2019 #55

    mm4440

    mm4440

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    Start with a Buick derived 4.6 l. Rover.
     
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  16. May 17, 2019 #56

    EzyBuildWing

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    re: Dream Engine...clean sheet:

    It's gotta' be a twin-rotor Mazda Rotary (13B?) peripheral-ported with efi with CNC milled lightweight aluminium billet end-plates, spinning at around 5500RPM for 160 HP continuous, DIRECT-DRIVING a 6-bladed ducted-fan.....this would be ultimate in simplicity, toughness and reliability.....only 3 moving parts and turbine-smooth!
    See vids below:

    this Time to climb record(13B) was financed by a New Castle chap who lives in a nursing home…. Unbelievable….!!!!

    CNC aluminium billet end-plates for Mazda build….. light-weight with replaceable cast-iron wearing inserts....

    Altrnatively, such a smooth lightweight physically-small engine would be ideal for this 'copter:
    this brilliant high-performance Hungarocopter prespins with electric, then 4-stroke engine starts….best sounding start-up of any 'copter!
     
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  17. May 17, 2019 #57

    TarDevil

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    There's a boatload of info on ducted fans in this forum. I'd start here.
     
  18. May 17, 2019 #58

    proppastie

    proppastie

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    Would depend on the analysis....Twin boxer should be the lightest....weight/reliability are the competing issues/compromises.
    Then again a twin opposed with a single throw two rod set up (if even possible) would be lighter yet.
     
    Last edited: May 17, 2019
  19. May 18, 2019 #59

    tcrbaker

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    I can't hold back any longer! It has to be the new Ford 1.5 liter 3 cylinder NA Dragon motor. It is small, light weight and has good horsepower and torque at low RPM. I would run it direct drive without the cylinder deactivation feature. As of yet it is not scheduled for any US bound cars, but the turbo version will be in the 2020 Escape. I can't wait to get one from a wreck. Thrust bearing is between the 2nd and 3rd cylinder (close to the flywheel), but that might not be a problem if you are willing to settle for around 100 hp. The cast in head exhaust manifold is another plus. I have yet to see what the horsepower is of the turbo version at 2500 rpm.
     
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  20. May 18, 2019 #60

    cluttonfred

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    For what it's worth, I am not at all excited about the idea of a new 200 hp engine, there are plenty of certified and uncertified options in that range and most are too rich for me. I would much prefer a "something old, something new" competitor to the Rotax 912. "Something old" meaning direct drive, air cooling, and simple construction and something new meaning modern single-point injection and electronic ignition for efficiency, reliability, and low cost. Bonus points would be awarded if it were an inverted, inline configuration for small cross-section and classic looks. A scaled up Zundapp Z9-092 would be great, say in 60/80/100 hp versions, as the oil tank integrated into the engine top is very slick. ;-)

    [​IMG]
     
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