Minimax wings on an Affordaplane

Discussion in 'General Experimental Aviation Questions' started by kirbylee, Nov 11, 2019.

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  1. Nov 11, 2019 #1

    kirbylee

    kirbylee

    kirbylee

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    I recently bought a 75% completed Minimax, mainly for the engine and a few other parts I needed for the Affordaplane I'm building. Since I haven't started building the wings yet, and have a pair of completed Minimax wings, which are very close to the AP in span, cord, and weight, I thought why not use the MM wings. I'm just not sure what would be involved in this project.
    Just guessing, I thought if I put the leading edge exactly where the plans show the Affordaplane wings go, with the same dihedral , and struts it might work just fine.

    I was hoping someone could tell me what I might be getting into. It sure would save a lot of time and money .

    Thank you
     
  2. Nov 11, 2019 #2

    Aerowerx

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    Not an expert here. I'm sure someone else will respond, but your idea should work since they have the same chord. However, IIRC, the Affordaplane wings are of ladder-type construction while the minimax has a conventional spar??? That would require some careful thought.
     
  3. Nov 11, 2019 #3

    FritzW

    FritzW

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    Setting the angle of incidence might take a little rework but easy to do. ...that and make sure the struts make sense.
     
  4. Nov 11, 2019 #4

    mullacharjak

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    You are halfway there with the wing in hand.Only fuselage and tail to go!I think the wing root straps have to come lower like an airbike setup.You can add a filler block at the root to take care of that.The wing strut angle will increase
    for the good.Will you need to realign the spar straps for the strut or use it as is?In the pietenpol aircamper the straps and strut angle are off by a lot and it works.Next is attacment of spars at the top between gusset d and e.Roughly the front bracket has to go about 6" back and the rear bracket forward about 20 inches.You can use 1"x 1 1/2" rectangle rod pieces for the brackets.Lower strut attachment appears simple as it approximates the minimax setup exactly.You have to tie the two strut ends to a 1'" round rod. A square 1" rod would be better.I think you will be the first with
    this innovation!
     
    Last edited: Nov 11, 2019
  5. Nov 11, 2019 #5

    kirbylee

    kirbylee

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    I think I have that figured out. The gussets for the aplane came with a predrilled hole for the wing attach fittings. I took a straight edge and made a line from the front one to the back.
     
  6. Nov 11, 2019 #6

    FritzW

    FritzW

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    You might need to move the wing attach fittings on the fuselage up or down a little to match the MiniMax spar fittings.
     
  7. Nov 11, 2019 #7

    kirbylee

    kirbylee

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    I
    I have the fuselage, horizontal stab, vert stab, elevator and rudder frames finished.
    As far as the struts, I was going to attach them to the cross tube 1" solid rod as per aplane plans, then to the strut attach fitting on the MM wing. I haven't looked at this close, but thats what I'm hoping will work.
    This is difficult to describe, but ….. Attaching the wings to the fuselage is what I'm looking at now. Since the aplane calls for "U brackets" bolted to the fuselage and then to the spars (tube spars)I could place the root end of the wing against the fuselage with the leading edge exactly where the plans show the Aplane wing. Then mark where the MM wing attach fittings touch the fuselage, and bolt a U bracket for each spar on the same line of incidence as the aplane plans show.
    If I remember correctly the trailing edge will be a few more inches aft than the aplane.
    Hopefully this makes sense, and thanks you guys for the help.
     
  8. Nov 11, 2019 #8

    poormansairforce

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    You need to line up the CGs from each wing, not necessarily the leading edge.
     
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  9. Nov 12, 2019 #9

    mullacharjak

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    plane.png
    Two ideas for the root attachment.Angle of incidence can be adjusted easily. You can think about wing folding also.The minimxa spar root straps are located at top end of spar so the wing lower surface might interfere with head clearence.These straps may have to attach lower on spar like the airbike/tandem airbike wing. afford.png
     
    Last edited: Nov 12, 2019
  10. Nov 12, 2019 #10

    FritzW

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    If you needed to raise the mount up a little more you could mount it to the top of the tube.

    top.jpg
     
  11. Nov 12, 2019 #11

    kirbylee

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    It's been around twenty years since I was into planes, I'm finding myself relearning many things this time around.
    I'm not sure if I understand what you meant by lining up the "CG"s.
     
  12. Nov 12, 2019 #12

    kirbylee

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    I think I'm going to have to mount it higher, because the wing attach fitting on the MM wing are near the top of the wing. Not sure I understand your drawing.
     
  13. Nov 12, 2019 #13

    FritzW

    FritzW

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    I think this is what poormansairforce is talking about. Line up the center of the CG ranges (+/-18% to 30% of the chord) instead of lining up the wing leading or trailing edge.
    CG.jpg
     
  14. Nov 12, 2019 #14

    FritzW

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    You could bolt your mounting block to the top of the main tube instead of the sides like you drew.
     
  15. Nov 12, 2019 #15

    kirbylee

    kirbylee

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    One thing I noticed today was the cord on the Aplane is 60 inches, the MM is only 54 inches.

    I think the MM wing is a Clark Y, not sure about the aplane. It shows two different ones anyway. I thought it said one of them was a Clark Y, but it wasnt shaped like a MM, so hellifiknow.
    The thickest part of the Aplane wing is 5 3/8 inches, the MM wing 7 3/4.

    Aplanes wings- 12 feet each.

    MM wings - 11 1/2 feet each
     
  16. Nov 12, 2019 #16

    kirbylee

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    That was my first thought, but I wasnt sure how. Actually I'm still not sure. I know i'm not following you, because, I keep wanting to ask," which is it, 18 or 30% of the chord?"
     
  17. Nov 12, 2019 #17

    kirbylee

    kirbylee

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    Gotcha
     
  18. Nov 12, 2019 #18

    mullacharjak

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    From the minimax flying manual optimum cg is 28-29% from leading edge. Range is 21-30 %(11.3-16.2")
    From affordaplane build manual cg range 25-30% of mean aerodynamic chord MAC(15-18").The tail areas are approximately similiar and AP has about 8 inch longer tail arm.Looks like it would work.
    The wing area of AP on paper is 117 sq ft but looks a lot bigger!
     
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  19. Nov 12, 2019 #19

    poormansairforce

    poormansairforce

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    I liked my MM cg at close to 30% so that would need to be located on the plane where the AP wing cg is located.
     
    Last edited: Nov 12, 2019
  20. Nov 22, 2019 #20

    kirbylee

    kirbylee

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    Since the minimax wing CG range is 21-30 % (11.3-16.2") the center is 13 3/4 inches from the leading edge of the wing?
     
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