Frame Assembly – Part 1

James Young · May 28, 2011

Well, I got the frame assembled (mostly)!  Still need to do a few bits (and all the cabling), but the frame’s put together and it fits like the plans said it would.  Great feeling when that pans out.

Assembled Frame

The frame was put together entirely from the design I described in my last post.  The MCU container that I’m using is sitting on a ring of 3mm foam rubber to isolate it from the body of the frame.

While the propellors are currently installed, that was mostly for looks and to verify that they swing as I was expecting.  I had to drill the center of the props out to 5mm, which means I’ve probably got the angle off on at least one.  But I have 30 spares, so it doesn’t matter much.

All bolts are 25mm M5’s, except for the four bolts holding the motor mounts to the frame, which are 35mm M5’s, and the bolts holding the motors to the mounts, which are 10mm M3’s.  I have not as yet applied Loctite anywhere, and won’t until I have completely finalized the build and I’m sure I won’t need to remove anything.

Motor mounting closeup

The bottom plate (forming the “leg”) on the motor mount is a piece of 20x60x3mm aluminium - the same template as the motor mounts themselves, except it was bent through a 45 degree angle at the 19mm mark.  This mark is in dashes on the template.

The idea is that the bent leg should act as a standoff from slightly rough landings, and the mount and standoff itself should bend reasonably easily (or swivel for that matter), providing a way to dissipate crash energy without bending the motors.  The arms themselves have a 19mm internal end cap pushed into them to discourage dirt and such getting in.

Frame - without MCU and motor mounts

The above photo is missing the 1/2” grommet I put into the center of the top plate for routing wiring, but it shows how the bolts and plates assemble to form the frame.

Task remaining to do are;  All the wiring, making the landing skids, and the battery holder.  My shipment of bullet connectors is on its way, so I’m not far off the test flight.

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