Wednesday, 12 November 2014

1.65m (65") Twin Boom pusher

This twin boom pusher is similar to the 1.3m Depron Spectre, however it has a straight 1.65m (65") x 190mm depron Armin wing and twin rudders.

1.3m Depron Spectre and 1.65m Twin Boom pusher

Initially it was designed it as a 1.8m light-wind slope soarer but didn't perform as well as I wanted. The longer tail booms and larger wing span made it too flexy and delicate. I was also comparing the performance to a motorless Phoenix 2000, which is a sensational sloper.
Shortened tail booms and wingspan stiffened up the airframe nicely and the addition of a motor fuselage turned it into an excellent FPV cruiser and medium wind FPV sloper. It tracks well in a straight line and has a decent glide angle but is quite agile like the Spectre.

Instead of using packing tape to cover the depron I used document laminating film, often referred to as New Stuff in the RC world. It is ironed on with a warm iron before bending the airfoil and fuselage, and works very well. It's tougher and easier to apply than packing tape.

Construction
See the depron wing build and Spectre overview videos for the basics, and the Spectre post on this blog.

Additional strengthening ...

6x1mm CF strip glued along the front of the elevator.


Heat bent UPVC brackets for the rudder to elevator joins.




I used twin rudder servos rather than one servo and a long vulnerable connecting pushrod between the rudders. Full length wing spar made from 2 Skyshark P4X spars joined with an internal CF rod joiner and epoxy. 

SPECS
Wingspan - 1.65m (68")
Length - 100cmm (36")
Airframe weight - 840g
Flying weight (2200mAh LiPo) - 1040g
Motor - Turnigy 2836 1100kV (260W)
ESC 30A Plush
Prop - 10 x 6"
Ailerons
Elevator
Twin rudders
TGY 9018MG servos x 2 (ailerons)
HXT900 servos x 3 (elevator and rudders)


I can email the Sketchup file if required



Initial slope soaring tests







27 comments:

  1. hi newton! where is the CG for this plane?thanks

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  2. Hello Axl, CG is about 60mm from the wing leading edge

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  3. Thanks.what if i move the tail closer to the wing,fuselage nose will be reduce also right?any effect to the plane considering my cg will be still in 60mm

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  4. Yes that is correct, shorter nose or lighter battery would work. You can shorten the tail as far as you want. Loops will become tighter, might need to reduce elevator action for smooth flight.

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  5. Hey Eng.Andrew, I am an aerospace engineer, and I am using your fantastic work as a reference for my own project so if you don't mind can I have the sketches and drawings? If you don't mind sending them to my email?

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  6. Hi Andrew! I was make twin boom pusher by your instructions (can send you pictures), and it flies well when I lounch it from hand, but with motor it can't gain atitude. Can you give some advice, what is wrong?

    Thank you in advance.
    Eduard

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    Replies
    1. What motor and prop are you using? Sounds like there is not enough power.

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    2. My comp crashes and I don't know did you get my reply. Motor is D2830-11 1000kV, prop is 10x6. All from Hobbyking. This motor/prop is on this plane, my first. https://www.youtube.com/watch?v=Z817qSJOoiY. Now I am building tricopter by your plans.

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  7. I am posting some pictures of pusher on my google +

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  8. It looks really good Eduard. Might be a silly question but do you have the prop on the right way and spinning in the right direction?

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  9. Yes. Direction of spining is OK, and on full throttle stream of air is pretty strong, hor. stab. lightly vibrates. I was also try with other prop, 9x5, but with same result. Over weekend I will post a short movie of lounching from hand, and with motor on. Maybe it help. Anyway, thank you very much. Bye.

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  10. Andrew thank you for the great build information and drawings. I have built and been flying both the 1.65 and Depron Spectre they both fly very nicely. The 1.65 m twin boom is my favorite at the moment.
    Edward Bennett

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    Replies
    1. Thanks Edward, that's wonderful to hear. Any photos or video I can see?

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  11. Andrew thank you for the great build information and drawings. I have built and been flying both the 1.65 and Depron Spectre they both fly very nicely. The 1.65 m twin boom is my favorite at the moment.
    Edward Bennett

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  12. Hello Andrew! First thank you for the great planes you show us how to make. Is there a build video or plans for the wing construction that I have missed somehow? I am new to building these and am unsure how to construct the wing.

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    Replies
    1. Specifically the wing, flaps & ailerons dimensions

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    2. Thanks. Yes heaps of build technique videos on my Youtube channel. Look for Depron wing build, depron Spectre build and Boom to wing join.

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    3. Specifically the wing, flaps & ailerons dimensions

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  13. Fantastic plane!
    Let me ask, What is the wing angle to horziontal? (attack angle)
    Why did you moved away from forward swept style of Spectre? Drawbacks or just simplicity?

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    1. Thanks Kornel. I didn't design in any angle of attack so it should be zero. I thought the forward sweep would not suit a longer wing, not stiff enough, and I just wanted to try it straight.

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  14. Sir, I have a question that my tricopter is of 875 grams and I used 2s/3000mAh battery with 1000kv motors of 150W power and my props are of 10*4.5 but my tricopter not flying, plz help me sit

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    1. Hello Vishal. It could be that 2S is not high enough voltage to lift it? Make sure your props are on the right way and the right prop for the spin direction and make sure motors are turning the right way. What exactly is the problem. Not stable? or not enough power?

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  15. Sir, when I increase my throttle my multi control board gets off or its gets blank, what's problem, plz help me sir.

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    Replies
    1. Wish I could help but I dont know the answer to that.

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  16. Hello! Amazing plane you have there! I was wondering if a 810kv motor with 30a ESC would increase speed?

    Thanks in advance
    Cole

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    Replies
    1. Thanks Cole. Lower kV would reduce speed with the same sized prop.

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