Wednesday, October 26, 2011

APM carrier for Hawk Sky and related planes

Inspired by the new Bixler Accessory Chassis on diydrones, I thought I would tidy my own setup and make my own adaptation for the Hawk Sky.  I haven't quite finished it but it looks promising enough to write up, and I think something similar would work on other models with a front hatch.

I cut the horizontal top plate using the opening as a template.  I just cut the cardboard "close enough" and then traced the opening directly onto the cardboard.  I used scissors for the cutting.

 I then did the same for the forward and rear risers.  I attached the three pieces with epoxy.  I positioned the pieces on the plane and then spread the adhesive on the front and back joints.  I used enough so that the joint didn't need any extra reinforcing.  Note that the fuselage opening bends down towards the front.  I attached the top plate to the front riser in such a way as to keep the top plate level.
 I tried a couple of different ways to attach the APM.  What eventually worked best was a cardboard carrier  bent to the appropriate size and hot glued to the top plate.

I cut some holes to run wires, see the ABC lights, and reach the reset button.  I attached the xbee and GPS on the top plate with velcro.  I didn't make a GPS mount like diydrones did; if I have reception problem I will do so.
 I uncased the Turnigy 9x receiver both to save weight and get clearance for the battery.  I replaced the standard 3-wire connectors with single wire connectors.  Later I'll get the rectangular 6-way connector and use that instead of multiple single wire connectors, but it doesn't seem to be a problem for now.
 The unit sits on top of the battery.  With the receiver case removed, there's just enough clearance for the 3S 2200 mAh 15C battery.  I velcroed the reciever on the bottom and hang the antenna wire out the side.  That's roughly equivalent to what I've been doing and haven't had a problem so far.  I provided some strain relief for the antenna by hot gluing it onto the board.
AUW for the unit with velcro is 13.3g. Still to do:  put some magnets to hold everything down, velcro or otherwise attach the APM to the lower carrier, and attach the pitot tubes.  I'm hoping to attach the tubes to the carrier if I can.

I'll update later when I've applied the finishing touches and gotten the thing into the air.

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