Planetary gear drive for corvair, Duel plug heads

Discussion in 'Corvair' started by don january, Mar 24, 2015.

Help Support HomeBuiltAirplanes Forum by donating:

  1. Mar 26, 2015 #21

    Midniteoyl

    Midniteoyl

    Midniteoyl

    Well-Known Member

    Joined:
    Sep 4, 2003
    Messages:
    2,406
    Likes Received:
    500
    Location:
    Indiana
    Maybe if you quit taking sniping shots at him, he would be more willing to answer your questions.

    Just a thought..


    And, a warning.
     
    cheapracer and akwrencher like this.
  2. Mar 26, 2015 #22

    Bill Clapp

    Bill Clapp

    Bill Clapp

    Well-Known Member

    Joined:
    Feb 17, 2015
    Messages:
    297
    Likes Received:
    290
    Location:
    Valdosta Ga
    The reality is that after thousands of hours behind corvair engines Ive not had a failure of the distributor or plugs. I know that there are areas where we can improve the reliability of the design for aircraft use. The biggest failure in any of these components has more to do with the pilot than any one component (for the most part) I've talked to two people this week through their first flights on brand new aircraft and It is probably the most important talk I give...and very little to do with any individual component. Many things are doable - but the return on the time and investment has to make sense as well.

    For that reason, I dont focus as much at this time on dual ignition more complex drive units.
    Back to building airplanes.... :)
     
    rv6ejguy likes this.
  3. Mar 26, 2015 #23

    akwrencher

    akwrencher

    akwrencher

    Well-Known Member HBA Supporter

    Joined:
    Oct 16, 2012
    Messages:
    1,104
    Likes Received:
    393
    Location:
    Gustavus, AK
    100%. I have had a number of cases in the shop with bad or fouled plugs, but I can't think of any off the top of my head that weren't caused by some other issue, i.e., they were the symptom of another more serious problem.
     
  4. Mar 28, 2015 #24

    WonderousMountain

    WonderousMountain

    WonderousMountain

    Well-Known Member

    Joined:
    Apr 10, 2010
    Messages:
    1,853
    Likes Received:
    193
    Location:
    Clatsop, Or
    Have you looked into the planetaries used by rotary engine guys? They've been using them a good while and use off the shelf auto components.

    LuPi
     
  5. Mar 28, 2015 #25

    don january

    don january

    don january

    Well-Known Member

    Joined:
    Feb 11, 2015
    Messages:
    2,641
    Likes Received:
    1,067
    Location:
    Midwest
    Ok duel ignition duel sparkplugs. and a third pickup off your crank, and by the way all sources come off your crank! what else in the motor runs with crank? water, air,time?
     
  6. Mar 28, 2015 #26

    don january

    don january

    don january

    Well-Known Member

    Joined:
    Feb 11, 2015
    Messages:
    2,641
    Likes Received:
    1,067
    Location:
    Midwest
    if you can trap the energy coming off the rod's and pistons, like the crank maybe thats the next step, or hidden step??
     
  7. Mar 28, 2015 #27

    RonL

    RonL

    RonL

    Well-Known Member HBA Supporter

    Joined:
    Jan 9, 2007
    Messages:
    456
    Likes Received:
    28
    Location:
    Texas
    With proper engineering and great care, the sliding motion of the pistons inside the cylinders can produce electrical energy. Of course it's not free, but the mass of copper and magnets would be a small fraction of the weight of an external configuration.
     
  8. Mar 29, 2015 #28

    TerryM76

    TerryM76

    TerryM76

    Well-Known Member HBA Supporter

    Joined:
    Sep 8, 2012
    Messages:
    485
    Likes Received:
    184
    Location:
    Tempe, AZ
    Be sure and correct me if I am wrong but I am rather certain that old Pawnee has dual ignition and that poor aircraft still suffered an unscheduled arrival. So,maybe dual ignition was not a great contributor for a successful flight in this instance. Was it the fuel perhaps or maybe tired components not operating or adjusted to specs?

    Yes, I like the redundancy that dual ignition should provide but most aviation maintenance texts like to point out that dual ignition provides for better efficiency of the fuel-air mixture. As others have mentioned, single plugs with electronic ignition is extremely reliable. Both my Tundra and Accord had well over 150,000 miles and a decade of service before I replaced the plugs.

    Now, from what I can see, we need someone to develop a reliable electronic fuel injection system that is of moderate cost. That is way out of my realm of expertise since I am more accustomed to working on carbs or mechanical fuel injection systems. I absolutely believe that simplicity goes hand in hand with reliability. WW and Bill Clapp and others I should name have contributed greatly to developing and promoting Corvair engines for aircraft applications. Maybe others with the savvy and resources can contribute by developing these systems further.

    Terry
     
    don january likes this.
  9. Mar 29, 2015 #29

    TFF

    TFF

    TFF

    Well-Known Member

    Joined:
    Apr 28, 2010
    Messages:
    11,641
    Likes Received:
    3,270
    Location:
    Memphis, TN
    I changed an engine in a Cirrus SR22 once, that had a Mag fail. The idiot pilot, who borrowed the plane, did not turn the bad mag off because he was scared it was going to stop. 10,000ft was plenty of altitude to check, but anyway. He flew it 150 miles with the bad mag occasionally firing random times, as the gear had lost some teeth. The misfiring mag burned holes in 3 pistons on a 400 hr engine, but it still flew. It takes a bunch to take a plane out as long as it is not on takeoff. We had a set of rings go in one cylinder, it pumped almost all the oil out in 10 minutes. Engine did not get damaged because pilot watched the gauges and he had an airport close. 15 minutes would have trashed the engine.
     
  10. Mar 29, 2015 #30

    don january

    don january

    don january

    Well-Known Member

    Joined:
    Feb 11, 2015
    Messages:
    2,641
    Likes Received:
    1,067
    Location:
    Midwest
    when your 8 ft, off the ground and at gross weight,unable to pull chemical dump because dump handle is wired shut to stop leak, a sick engine is a disaster if you can't get clearence over the trees. I feel the sick motor was just a small part to that crash. never block off one of your emergency units built into the aircraft. "No brainer"
     
  11. May 23, 2015 #31

    ekimneirbo

    ekimneirbo

    ekimneirbo

    Banned

    Joined:
    Oct 31, 2014
    Messages:
    1,009
    Likes Received:
    324
    Location:
    Deep South
    If a mag was used as a backup ignition in case of electrical failures, does the prop on your Corvair have the ability
    to turn the engine over after it has stopped running? I'm thinking that the backup mag could be coupled in the case of an engine out rather than continually driven.
     
  12. May 23, 2015 #32

    Will Aldridge

    Will Aldridge

    Will Aldridge

    Well-Known Member

    Joined:
    Oct 30, 2009
    Messages:
    867
    Likes Received:
    362
    Location:
    Northern Utah
    Some of the Rotary guys are using the magneto type ignition (stator?) system off an outboard engine, or at least it's been posted on the email list. But it's easy in the rotary since you can mount it between the psru and the block. Looks like a pretty sweet setup to me. Maybe something similar could be mounted on the back of the corvair?
     
  13. May 23, 2015 #33

    don january

    don january

    don january

    Well-Known Member

    Joined:
    Feb 11, 2015
    Messages:
    2,641
    Likes Received:
    1,067
    Location:
    Midwest
    I know William Wynne does the duel point set up in his conversion's, and as far as I know thats it. sure it's great inless the disributor fails. I've personanly have'nt read or heard of any problems. Not sure what Mr. Clapp is doing for his ignition? purly stock or also duel point? If you think about it there is just a small shaft keeping the engine fireing on corvairs and most all other motor's. Clapp states he has a good setup for the corvair in post 11 and that would be a good thing to invest in.
     
  14. May 25, 2015 #34

    ekimneirbo

    ekimneirbo

    ekimneirbo

    Banned

    Joined:
    Oct 31, 2014
    Messages:
    1,009
    Likes Received:
    324
    Location:
    Deep South
    I don't think it would be that difficult to make some type of magneto backup that could be easily engaged in the event of a failed igniton. The thing about a continuously running mag is that it would wear unnecessarily while providing
    no real benefit and it probably would sap a couple of hp. Having it available only when needed would help to assure extreme longevity.The question I have is that if the electrical system was the cause of failure and the starter wouldn't work......would the windmilling propellor be sufficient to restart if a mag was available?
     
  15. May 25, 2015 #35

    don january

    don january

    don january

    Well-Known Member

    Joined:
    Feb 11, 2015
    Messages:
    2,641
    Likes Received:
    1,067
    Location:
    Midwest
    IMO : If the prop size was big enough and airspeed fast enough then the Corvair would windmill. Many corvair engines have been flown without starter set up's front or rear. I find it odd that the leading authority's of the corvair convertion's do not chim in and give there expert opinion. I guess to busy !
     
  16. May 25, 2015 #36

    Bill Clapp

    Bill Clapp

    Bill Clapp

    Well-Known Member

    Joined:
    Feb 17, 2015
    Messages:
    297
    Likes Received:
    290
    Location:
    Valdosta Ga
    Just to answer a couple past questions. As far as the distributor, we have a purpose built one from an old core. It has 18-20 degrees of centrifugal advance built into it and a set of points and a Crane electronic pickup for a dual ignition source. Our distributors also incorporate a ball bearing for the main shaft to increase reliability and timing accuracy.

    As far as windmilling, it really depends on each engine/prop combination and speed. You have to have enough are on the prop to overcome the static engine friction. A heavy or light prop may not have much effect other than flywheel enertia effect. A lighter prop would be easier to stop but also easier to get moving....You may have to try your combination as see what speed the engine would begin windmilling at. Be ready to do so over an airport :)

    Hope this helps :)
     
    dcstrng and don january like this.
  17. May 26, 2015 #37

    ekimneirbo

    ekimneirbo

    ekimneirbo

    Banned

    Joined:
    Oct 31, 2014
    Messages:
    1,009
    Likes Received:
    324
    Location:
    Deep South
    Thanks......I probably would try it with the engine mounted on a trailer behind my truck. Then I could see what effect different speeds had.:)
     
  18. May 26, 2015 #38

    BJC

    BJC

    BJC

    Well-Known Member

    Joined:
    Oct 7, 2013
    Messages:
    9,550
    Likes Received:
    6,322
    Location:
    97FL, Florida, USA

    If you know why it quit running and can correct it right away (suitch back to the tank with fuel :nervous:) then a windmilling propeller / engine is a plus. If you need to glide to a suitable crash spot, a stopped propeller will produce a better glide ratio.


    BJC

    PS. It will windmill at a lower speed than will be required to start windmilling after it has stopped.
     
    akwrencher and don january like this.
  19. Jan 27, 2016 #39

    rv7charlie

    rv7charlie

    rv7charlie

    Well-Known Member

    Joined:
    Nov 17, 2014
    Messages:
    438
    Likes Received:
    172
    Location:
    Jackson
    Sorry to be a little late with this (just beginning to catch up on threads here on HBA).

    Bill,

    Can you provide some examples to support your contentions about planetaries? Specific engines that are overweight, harmonic-plagued, have lube issues, more, due specifically to the use of planetary reduction drives?

    Charlie
     
  20. Jan 27, 2016 #40

    Bill Clapp

    Bill Clapp

    Bill Clapp

    Well-Known Member

    Joined:
    Feb 17, 2015
    Messages:
    297
    Likes Received:
    290
    Location:
    Valdosta Ga
    Hey Charlie. I never got to see one of those planetary drives on a corvair so honestly not sure about all the development problems or benefits since its not flying. I just know that our direct drive setup is as easy as it gets (no extra parts!) It would be interesting to see one but not in our planning stages when what we have works well for the power range of the engine. I just remember all the problems that plagued Eggenfellner when he did his SUbaru conversions....a long story.

    Bill
     

Share This Page

arrow_white