3/4th Scale Replica Bell P-39 Airacobra

Discussion in 'Wood Construction' started by Eagle92lightning, May 13, 2019.

  1. May 13, 2019 #1

    Eagle92lightning

    Eagle92lightning

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    I am brand new to the world of building aircraft, I have been designing them on paper for years but I have never built one. I can't even fly yet (nor have I ever flown). I want to build something decently small but still fun to toss around the sky. I have been doing some looking but can't seem to find any plans for a wood P-39 Airacobra. And if you are asking why I chose the Airacobra its simple, I wouldn't have to bother with a taildragger endorsement to fly it! But if someone can direct me towards some plans for 3/4th scale P-39 it would be a huge help!
     
  2. May 13, 2019 #2

    lakeracer69

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    No plans have ever existed that I know of. Your driveline development will be interesting to say the least.
     
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  3. May 13, 2019 #3

    Eagle92lightning

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    It should be as simple as taking the real thing and scaling it down, a few work arounds of course but maybe transfering the rotational energy from the crankshaft to the driveline via a belt and pulley system. The fun part is going to be getting a running small block Vee 8. I realize how idiotic that belt idea is now...
     
    Last edited: May 13, 2019
  4. May 13, 2019 #4

    nerobro

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    The P-39 was a pretty slim fitting aircraft to start with, it might look funny as a 3/4 scale plane, as you'd need to do some cartoony things to the cockpit area to make it work for you. I'm not aware of any plans for it.
     
  5. May 13, 2019 #5

    Dana

    Dana

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    No, it's not that simple. Dealing with torsional vibration issues in a long driveshaft is something that makes brave engineers weep. Getting a tailwheel endorsement would be a lot easier.
     
  6. May 13, 2019 #6

    Victor Bravo

    Victor Bravo

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    I had a friend who passed away, along with his daughter, his grand-daughter, and his son-in-law, because of a driveshaft issue in a homebuilt aircraft. This man was a detail-oriented, high-end mechanical engineer with many years of experience designing CNC machinery for one of the largest manufacturers in the US. Even with that level of experiece and all the resources he had available, a catastrophic driveshaft failure happened.

    Dana's correct 1000% - get the tailwheel endorsement and you will have five or ten better options than the P-39, some of which you might be able to complete in your lifetime.
     
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  7. May 13, 2019 #7

    nerobro

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    Lets be real here, why bother with a driveshaft if you aren't putting a 37mm cannon up front. So, driveshaft shouldn't be an issue. Still, the plane is going to be tricky to to.
     
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  8. May 13, 2019 #8

    TarDevil

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    Bob Hoover said the P-39 does great lomcevaks.

    Don't do this at home! :)
     
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  9. May 13, 2019 #9

    Derswede

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    But that takes all the fun out of having a P39. Had one in NC some years ago, spent most of its time peeing coolant onto the runway. Great looking airplane, maybe a paintball cannon instead of the 37mm Cannon? Sounds like a project now....

    Derswede
     
  10. May 13, 2019 #10

    pictsidhe

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    If you think the drivetrain will be easy, you lack the knowledge to make it work...
     
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  11. May 13, 2019 #11

    Eagle92lightning

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    I understand where y'all are going with this but I am ambitious, and there truly is no point in having the 37mm cannon, guess I need to think about this some more. Thanks anyways!
     
  12. May 13, 2019 #12

    BJC

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    Don’t let a tailwheel deter you. If you learn to fly properly, flying with a tailwheel will be easy.


    BJC
     
  13. May 13, 2019 #13

    Eagle92lightning

    Eagle92lightning

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    Eventually I want to learn to fly a taildragger, and I understand the principals of aerodynamics and flight like no ones business. I have wanted to be a pilot since I was 7.
     
  14. May 13, 2019 #14

    pictsidhe

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    I plan to leave some nice big gun bays in my wings. The paintball guns for them may be a few years away, though...
     
  15. May 13, 2019 #15

    cdlwingnut

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    met some Tusgegee airmen a few years ago who flew the p-39 and p-51 they said the only thing the p-39 was good for was that you could roll the window down like in a car toss your scarf out and look cool, otherwise it was junk
     
  16. May 13, 2019 #16

    nerobro

    nerobro

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    It's not worth talking paintball guns on planes :) Even a 60mph car turns a paintball run into a "are you shooting yourself in the windshield" exercise.
     
  17. May 13, 2019 #17

    ScaleBirdsScott

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    I have a lot of experience with paintball. I've even played shooting from a helicopter. Never tried shooting forwards doing 60mph tho. Really curious what happens. But almost certainly not going to get good trajectories.
     
  18. May 13, 2019 #18

    nerobro

    nerobro

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    You aim up at about 35 deg, and it comes back and hits your windshield with about a 1 second flight time. :) though it's been a long time since I did that.

    So do I. I went to celebrity paintball 1... and i'm going to it's long lost grandchild, Living Legends 12 this weekend. I miss the old AGD.
     
  19. May 13, 2019 #19

    radfordc

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    I quote three things you said, "I am brand new to the world of building aircraft", "It should be as simple as taking the real thing and scaling it down", " I realize how idiotic that belt idea is now...". I think you've identified the problem.

    Even building a very simple airplane from proven plans is a big deal for a new guy. Good luck on the project. You might want to compare notes with the guy who wants to design a scale P-51 ultralight.
     
  20. May 14, 2019 #20

    Wanttaja

    Wanttaja

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    Wonder if one could use a small gas turbine engine mounted up forward in the more-conventional location......

    Ron Wanttaja
     
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