1/2 scale warbirds

Discussion in 'Warbirds / Warbird Replicas' started by BBerson, Nov 5, 2019.

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  1. Dec 1, 2019 #41

    n45bm

    n45bm

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    Hi. I also have the plans for the CX4, but would like to make it the fastback version. Do you have the drawings for the turtle deck formers?
     
  2. Dec 2, 2019 #42

    olphart

    olphart

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    No, unfortunately, I don't. I eyeball engineered it using the TLAR rule ;)
     
  3. Dec 2, 2019 #43

    wwz7777

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    I was wondering what you all think of the basic WAR airplane, say the Fw-190? It seems like a basic airplane that the average person could build with tools already around the shop. Other than letting the weight get out of control, are there any other problems (aerodynamically or structural) that should be considered? Is it too small? They were basically scaled at 58% to get the wing large enough IIRC.
     
  4. Dec 2, 2019 #44

    cluttonfred

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    I can't speak to the WAR replicas, but FWIW, if you start with a bigger plane then 50% is easy to do. I am not joking, I mean if you run the numbers for a modest sport aircraft then something like the big Republic P-47 Thunderbolt comes out at about 50% scale and the relatively deep and portly fuselage makes it much easier to hide the 100% scale pilot. The Grumman radial-engine fighters (Wildcat, Hellcat, Bearcat) might also work out that way as well, though the scale would be higher for the same wing area.
     
  5. Dec 2, 2019 #45

    ScaleBirdsScott

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    For reference, a 63% Hellcat comes out pretty close to an RV8. A 50-53% comes out more like the RV3.

    Speaking of which, my LiteFighter concept incidentally is very close to the RV3.

    Worry less about what % scale, and more about just what is the size of the final airplane you want, generally based on the engine you'll choose; then figure out the scale from there.

    For me, the scale % is usually the least useful number.
     
  6. Dec 3, 2019 #46

    wwz7777

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    Maybe my thoughts should be in a different thread? I’m not really focused on the scale. I’m not an engineer and so I try to find similar/proven construction designs to use for a replica. WAR has a structure that is proven. If I build a replica with similar size and weight, then I don’t feel I need to redo the stress analysis. There are other construction plans/methods that could be used to build a replica. If I change the size of a design then I will have to have the design checked by an engineer. I don’t know how to do that and would need guidance on finding an engineer that would be willing to help me.
     
  7. Dec 3, 2019 #47

    mcrae0104

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    Did you redesign the bulkheads to the shape you wanted, or build the standard airplane, and then add another set of bulkheads and frames on top?
     
  8. Dec 3, 2019 #48

    ScaleBirdsScott

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    Down this road lies madness.

    It's totally possible.

    But it may lead to madness. And lost relationships, expenditures of money far in excess of what it should have cost, and oh yeah, probably 5-10 years of valuable lifespan.

    I mean I'm living proof! Hopefully, someday, within the next few months, it'll have not been for naught and I'll have a flying warbird. But just sayin'. Choose wisely the starting point.

    If your talking about taking WAR, straight up takin' a set of plans and just being like "I want a YAK-3U instead of a FW190" like, that's all WAR did anyway. So go for it. Take their box frame and just change the shape of the foams before glassing it all. The wings got their slightly unique shapes, and some numbers probably got ran to just cross-check some things, but it's basically just a plywood and stick box covered in a lot of extra stuff so it really comes down to whether you're trying to change anything about that base model and how it's built besides just that outer fiberglass shape.

    IMO the wood with carved foam over top and then wrapped in glass; not really the best method. Certainly however it's easy for a one-off. But there's countless other examples of aircraft one can mimic that isn't technically a warbird but gets you the right bones. WAR as far as I'm aware was based on the KR-2. So it just did that at the outset anyways as well.

    I'd pick something that looks and flys good, and gets built in the right way and has the features you want as a starting point, and not just stick to WAR because it's already a warbird, unless the WAR is exactly the specs and features and construction and size you want. Then in that case it's probably as easy as you can make it on yourself.

    Still the road leads to madness.
     
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  9. Dec 3, 2019 #49

    olphart

    olphart

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    Used the standard front and rear upper bulkheads, and the standard lower bulkheads, then made new upper intermediate bulkheads to fit the profile
     
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  10. Dec 3, 2019 #50

    WARPilot

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    Our EAA34 chapter has 4 WAR aircraft in various stages of build. We also have a set of P-40 plans and would like to build that design with mods that could drastically reduce the weight. One idea is using carbon fiber square tube to build the base structure and molding skins and then attaching. No foam and no excess resin. Also, the ailerons and tail feathers should be fabric covered for lightness and balance.
    The goal is to get a basic empty WAR weight down to high 500# weight but less than 620# as published by WAR. Most weight close to 800 # empty.
    Foam will absorb some moisture over time so we get rid of that issue.
     
  11. Dec 3, 2019 #51

    WARPilot

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    Here are some of our WAR projects
     

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  12. Dec 3, 2019 #52

    wwz7777

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    WARPilot, is that first Yellow 14 picture the F model that George Dawe built? Where are you located?
     
  13. Dec 4, 2019 #53

    WARPilot

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    Yes
    We have been having trouble with the canopy and the landing gear. The canopy doesn’t fit well at the front wind screen. The gear seem to lockup during retraction or extension at the halfway point.
     
  14. Dec 4, 2019 #54

    WARPilot

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    Located at KGKY, Arlington Tx
     
  15. Dec 4, 2019 #55

    wwz7777

    wwz7777

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    I visited George at his home in SoCal before he started painting the WAR. Are there any WAR birds flying around there?
     
  16. Dec 7, 2019 #56

    Saville

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    This is how I arrived at the 66% scale when I was pondering an ME-262 replica:

    I fly an RV-8. So I know it's cockpit dimensions and how that works out for me. So I divided the length of an rv-8 by the length of an ME-262 to get a rough scale factor and it came out at 60%.

    2/3's seems like a reasonable starting point for any replica.
     
  17. Dec 7, 2019 #57

    pictsidhe

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    It depends on what you are starting with. When sizing my project, I started with the approximate wing area and an idea of the span I wanted, then looked at what scale would fit. Then check the cockpit is feasible without getting too cartoon. 2/3 works nicely for my Hurricane. If I was building a Yak-3, it would be around 90%. A Spruce Goose? 1/10 might be about right! If I ever build a 262, 2/3 would likely be my pick for that, too.
     
  18. Dec 7, 2019 #58

    WARPilot

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    The full scale P40 specs.
     

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  19. Dec 8, 2019 at 12:22 PM #59

    Saville

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    That's true. Which is why I only start there. The RV-8 dimensions ( especially cockpit room) are good guides.

    But as you say, if you pick a plane with an especially small cockpit, then 2/3's isn't going to be big enough. And then there's aerodynamic tweaking to be done.
     

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