Shadow

[Malky]

I've been interested in twin boom inverted V aircraft for a while. I followed this project:
https://www.flitetest.com/articles/rq-7-shadow-scratch-build
and thought I could build a slightly less scale version using the Flite test A motor, 850 mh battery, 5mm carbon fiber tubes and foamboard.

Mine weighs 330g (with battery), has a 76.4cm wingspan, 12 cm chord and wing area of about 916 sq cm.

I based the construction off the mini P-51

I started with a test piece

 

[Malky]

Made a simple fuselage. Angled up the aft of it to allow more air to get to the prop.




Heaps of room for the gear and will move the battery fwd/aft for C of G trim.

 

[Malky]

Wing was tricky. I needed to have the 4 servos mounted within the wing and have the 2 rods fitted inside (not on top or bottom). I tinkered with the practice wing to find the best way. I probably over engineered it and added too much weight.

 

[Malky]

Drilled a hole in carbon fiber and used dremel tool to elongate it.
Used those servo connector things for V tail.

 

[Malky]

Finished but not flown yet

A bit tail heavy. Had to add weight to nose as battery is fully forward. Heaps of room for FPV






A basic run up and system test:

 

[Malky]

Was too tail heavy, added weight and still about 5mm to far back. Put in an older but bigger battery but it died 2 min in. Should be easy enough to fix.

 

[JasonK]

Here is an A-pack sized twin boom A tail (inverted V), plans and all

https://forum.flitetest.com/index.php?resources/sub-250g-fpv-atail-pusher.231/

 

[JasonK]

your build looks good. you could also extend the nose a bit so you can move the weight forward.

 

[JasonK]

do you have any slop in your tail surface controls? with how you pass the pushrods down that CF tube, it looks like there could be a bit of slop.

you can test by pressing gently on the surface and see if it can move without the servo moving.

 

[Malky]

Here is an A-pack sized twin boom A tail (inverted V), plans and all

https://forum.flitetest.com/index.php?resources/sub-250g-fpv-atail-pusher.231/

Hey Jason, thanks for sharing that stuff. I wasn't sure if the foamboard would be strong enough but looks like it is. Once I saw the carbon fiber rods, however, I was hooked. The tricky bit was affixing to the wing AND getting the control rods down. I drilled a hole in the boom and fed the control rod out with a bend.
No slop in the control surfaces but one aileron servo sticks in full deflection. I haven't played with the throws yet but I will only buy decent servos from now on.
I didn't build it with FPV in mind but now it's made...

 

[Malky]