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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")
Chord - 190mm (7.5")
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







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29 comments:

  1. Unknown21 December 2014 at 03:50

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

    ReplyDelete
  2. Andrew RC Newton21 December 2014 at 07:33

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

    ReplyDelete
  3. Unknown21 December 2014 at 10:06

    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

    ReplyDelete
  4. Andrew RC Newton21 December 2014 at 10:13

    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.

    ReplyDelete
  5. Anonymous5 April 2015 at 05:38

    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?

    ReplyDelete
  6. Unknown28 May 2015 at 18:36

    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

    ReplyDelete
    Replies
    1. Andrew RC Newton28 May 2015 at 20:55

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

      Delete
    2. Unknown28 May 2015 at 21:56

      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.

      Delete
  7. Unknown28 May 2015 at 21:56

    I am posting some pictures of pusher on my google +

    ReplyDelete
  8. Andrew RC Newton29 May 2015 at 11:00

    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?

    ReplyDelete
  9. Unknown29 May 2015 at 15:11

    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.

    ReplyDelete
  10. Unknown11 August 2015 at 08:48

    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

    ReplyDelete
    Replies
    1. Andrew RC Newton11 August 2015 at 09:02

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

      Delete
  11. Unknown11 August 2015 at 09:31

    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

    ReplyDelete
  12. Web Guy3 September 2015 at 15:37

    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.

    ReplyDelete
    Replies
    1. Web Guy3 September 2015 at 15:40

      Specifically the wing, flaps & ailerons dimensions

      Delete
    2. Andrew RC Newton3 September 2015 at 16:11

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

      Delete
    3. Web Guy3 September 2015 at 17:01

      Specifically the wing, flaps & ailerons dimensions

      Delete
  13. Unknown26 September 2015 at 19:25

    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?

    ReplyDelete
    Replies
    1. Andrew RC Newton26 September 2015 at 20:45

      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.

      Delete
  14. Unknown15 April 2016 at 15:45

    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

    ReplyDelete
    Replies
    1. Andrew RC Newton15 April 2016 at 15:51

      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?

      Delete
  15. Unknown15 April 2016 at 15:46

    Sir, plz reply me soon.

    ReplyDelete
  16. Unknown18 April 2016 at 00:23

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

    ReplyDelete
    Replies
    1. Andrew RC Newton18 April 2016 at 06:30

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

      Delete
  17. Cole Palmer RC19 January 2017 at 15:35

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

    Thanks in advance
    Cole

    ReplyDelete
    Replies
    1. Andrew RC Newton19 January 2017 at 16:02

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

      Delete
  18. Unknown17 February 2018 at 03:25

    Hi Newton can you guide us what is the wing chord of 1.65m spectre?

    ReplyDelete