65" twin boom FPV cruiser

by apnewton | November 12, 2014 | (12) Posted in How To

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. 

 

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. How to video below. 

Construction

See the depron wing build and Spectre overview videos for the basics.

Additional strengthening ...

6x1mm CF strip glued along the front of the elevator

Heat bent UPVC brackets for the rudder to elevator joins.

 Full length wing spar made from 2 Skyshark P4X spars joined with an internal 80mm solid CF joiner and epoxy.

I used twin rudder servos rather than one servo and a long vulnerable connecting pushrod between the rudders.

 SPECS

Wingspan - 1.65m (65")

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)

 Dimensions

 I can email the Sketchup file if required

Powered flight maiden

Fuselage build using New Stuff or laminating film.

 Initial slope soaring tests

MATERIALS
Bulk Depron - http://www.tradewarehouse.com.au/more/depron-foam/white.html
Skyshark P4X spars - http://www.kitesandfunthings.com/ProductInfo.aspx?productid=SSP4XCAM0
New Stuff iron-on film - EZload laminate - http://gbcaustralia.com.au/products/display_consumable.aspx?ConsumableTypeID=213
Blank ID cards - Ebay http://www.ebay.com.au/usr/y2store?_trksid=p3984.m1439.l2754

Newton Airlines blog (Plans) - http://newtonairlines.blogspot.com.au

Website - http://anewton.net

 

Pin point accuracy FPV landing



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COMMENTS

28th St. Air on November 14, 2014
Awesome article. Loved your landing. That was FPV gone TPV "third person view" :)
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apnewton on November 15, 2014
Flying by feel! Luckily the nose cone is soft foam, didn't hurt at all.
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Grearson on November 15, 2014
Building the Depron Spectre right now due to the nice looks, just waiting for my MG servos from China to complete it. As i am now to buildung and flying, i hope mine flys as well as yours =)

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apnewton on November 15, 2014
Good luck, let us know how it goes.
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KiwiRCFlyer on November 15, 2014
Awesome work! I have the Specter V2 with the forward swept wings and I was wondering how the stall characteristics would be affected by a straight wing. Did you notice much difference?
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apnewton on November 16, 2014
Thanks Kiwi. No I haven't noticed any increased stall tendency but it's quite a different wing to the smaller Specters. More of a glider wing I suspect.
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Desert Wings on November 16, 2014
I love your builds and fly videos. I really need to find a place to slope.
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tmask32 on November 17, 2014
I built a twinboom exactly like that last year. Looks gr8. Its become my main fpv platform.
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dav on November 19, 2014
Thank you very much for your article!
I ended up building the spectra and I'm waiting to come on the radio (my first plane)

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apnewton on November 19, 2014
Nice one Dav. Good luck. Best tips from me are ... wait for a calm day for your maiden and do plenty of test glides first.
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apnewton

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65" twin boom FPV cruiser