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Apr 26, 2020, 08:07 AM
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Build Log

Klingon Bird of Prey inspired craft - plans


Hi Folks,
I want to share with you my new scratchbuild project.
It is not exactly Bird of Prey but you will notice inspiration easily

My Bird of Prey - project completed (3 min 22 sec)


Wingspan: 99cm (40in)
Length: 83cm
Weight to fly: 730g
Engine: AXN-2208-KV2150 with 6.5x4 propeller
Accu: 3S 1300mAh

Project is finished but I want to try work on stable anhedral wing flight a little.

Added plans to #6
Last edited by robertus; May 06, 2020 at 09:27 AM.
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Apr 26, 2020, 09:02 AM
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I've designed this project in sketchup.
Apr 26, 2020, 09:11 AM
treefinder
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Wow! Excellent work! She flies a treat!

So what actually happened when you went anhedral? Roll off? Forward swept plus anhedral is certainly pushing the flight envelope. But seems very stable with positive dihedral or flat.

Good stuff!
Apr 26, 2020, 09:32 AM
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Yes springer, in flat and dihedral wing configuration she is very stable and a nice flyer, but in anhedral I don't have controls at all. Control surfaces seem do not work.
I've tried twice, at 2:32 and 2:50 and in the maiden flight tried too. I think, it may be connected to CoG above a wing surface, but I don't know for sure.
Apr 26, 2020, 09:55 AM
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Build steps.
All is made from depron 6mm
Apr 26, 2020, 10:37 AM
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Wing mechanism close up and battery bay placement after CoG experiment.

CoG is 22mm before wing leading edge
Last edited by robertus; Apr 26, 2020 at 10:52 AM.
Apr 26, 2020, 10:50 AM
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Maiden flight (without painting) and plans

My Bird of Prey - maiden flight (4 min 42 sec)


Notice that in the plans there are no thickens of foam, You need to trim ribs and other parts depending on foam thickens you use.
I've build BoP mostly from 6mm depron, only "engines" are from 3mm foam.

There is also addition to the plans in post #33
Last edited by robertus; May 04, 2020 at 01:59 PM.
Apr 26, 2020, 01:44 PM
Registered User
I have to give it to ya Robertus!!! You are ALWAYS on the edge with your designs. This one is AWESOME!!!
Apr 26, 2020, 08:14 PM
skumgummi dave
Great design Robertus. Thanks for the plans and video.

Dave-
Apr 26, 2020, 10:00 PM
Retired CAD guy
birdofplay's Avatar
I took those plans and had a go in CAD with my usual Layout stuff.

I can get it done with 3 sheets of MPF.

And I have asked robertus if I can CNC these for builders in the USA.

We'll see how it go's when the sun rises on Poland ;>}

If not I'll just cut one for myself.

C U L8r

Bob
Apr 27, 2020, 12:36 AM
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Hi Bob, I've just found your PM
You have my approval to cut this plans, just put info somewhere that is my design.
The plans are free, but if someone needs a help with cutting you can cut. My shared plans are always free of charge. When I was beginner I was building planes based on someone else plans and now I'm paying off a debt to the community. Generally my plans are not PnP, and you have to have some experience in scratch builds but it's not a rocket science. I can see a lot of my designs around the world, and this makes me happy.
Best luck for all modellers in this tough times.
Apr 27, 2020, 12:52 AM
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Suggested reinforcements. Wing of course and the neck needs something. On the neck I've added pain strip after the maiden.
Apr 27, 2020, 03:02 PM
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Thank you Robertus !

I will finish up my layout and cutting files and let the guys know.

Bob @ Hoosier Cutout Service
Apr 28, 2020, 07:43 AM
Retired CAD guy
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So here I offer my Layout on 2+ sheets of MPF, Model Plane Foam, and a
3mm sheet for the two Engine cover parts.
Pic and PDF

I can cut these all out via CNC if you want to avoid the Cutting hassles and tedium.
The layout is segmented for easy Box packing for shipment.

I'll be asking $40 + shipping

Bob @ Hoosier Cutout Service
Last edited by birdofplay; Apr 28, 2020 at 07:54 AM.
Apr 28, 2020, 10:29 AM
Registered User
Quote:
Originally Posted by robertus
Yes springer, in flat and dihedral wing configuration she is very stable and a nice flyer, but in anhedral I don't have controls at all. Control surfaces seem do not work.
I've tried twice, at 2:32 and 2:50 and in the maiden flight tried too. I think, it may be connected to CoG above a wing surface, but I don't know for sure.
Yes, the combination of forward sweep, anhedral and CG above where the wing joins the fuselage will be inherently unstable in roll and yaw (pitch stability could be just fine with proper CG).
A stabilization system or super fast reflexes can solve it.


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