Decalage angle

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proppastie

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One of Skyboy owners send me this message.
Yes , you have an "aft CG " marginal stability aircraft,....keep the nose down and the speed up..... I hope you can fix it......perhaps your wind-tunnel friend can make a quick Styrofoam model and put it in the wind tunnel.
 

plncraze

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The tufts will have your answers. The battle between surface area and streamlining is tough.
 

Eugene

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OK, looks like, this will be more ore less final configuration. Spend some time to make sure that it is inline with airframe. Wondering if this whole thing will make tail boom stronger and eliminate deflection under load.

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Eugene

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This definitely turned into a pretty solid structure to my surprise. For sure I will not be afraid to fly with it. And maybe I’m reading too many books lately, but it looks better this way. But maybe it’s in my head.DA754C34-C59F-4471-9360-8229A33B5B0F.jpeg68C09BAD-8FB1-47A3-A1CF-866F520019CB.jpeg9B65B8C0-7A63-4DF4-91E6-ADE65F5EBDA2.jpeg450A009B-5124-4472-87E3-4BFE633FD277.jpeg99051A16-68BC-49D7-B8FF-C1FD3D0ECA9B.jpegF227E489-6917-454B-BE93-AC74B76006C2.jpeg8924D627-1596-4B05-B32D-80095391513B.jpeg
 

Eugene

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I was kicking different ideas for a while about best way to do this. This is what I came up with so far. It should work. Top part will remained open so I can fill it up with liquid foam.


9BBF8FDC-DD98-49EB-B38E-5AB83A73758D.jpeg 46AC182F-915B-469C-AFEC-CD5EDAF1CE33.jpeg 29F1E43D-53FC-4E5B-9BD4-C99C85151512.jpeg E1C7116C-39FE-4F8B-9694-DA4FA381C3E9.jpeg A5845BDD-5EA3-406C-BAA9-6E2EA5D676A8.jpeg 56B87E2F-2973-4BC0-8E76-75F4395417FB.jpeg
 

Eugene

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If you attach this contraption, how much more difficult is it going to be to remove the rear fiberglass?
Not if. This contraption is already attached to the rear fiberglass.

My plan is to create flying foam plug. Should be possible to add or remove foam between tuft test flights. If I see any drag improvement at all, then I will park airplane and finish this plug. So, I can make molds from it.

After removing molds this whole contraption will be destroyed down to original rear fiberglass afterbody. That old fiberglass should have very little damage to it. So I can still fly and use new mold to build new afterbody right in my living room in January.

Screen Shot 2019-09-18 at 22.27.41.png Screen Shot 2019-09-18 at 22.24.01.png Screen Shot 2019-09-18 at 22.14.55.png Screen Shot 2019-09-18 at 22.14.06.png
 

Eugene

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I was trying to find pictures of very successful German aircraft - flight design. I wanted to see how smart people with wind tunnel capabilities designing rear fuselage. And I found these pictures on their website.
 

Eugene

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267FD924-DDF6-44AA-87AB-A20FEE10FE43.jpeg Still not enough!!! Will get more tomorrow . Anybody have any doubts that this is hundred times more fun than flying straight and level ???!!!
 
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