After the mad rush of getting my ultimaker operational and making my Iron Man mask I have finally been able to get back to my FPV build of the 215 Hopper. I now have all the frame components made and there are some significant changes from the original.
To start off with though, a tale of my first FPV session. As soon as I had all the pieces needed to fly FPV I had to try it. Knowing that my dedicated FPV build was still a couple of weeks away I rigged up the Hopper, mostly with cable ties and temporary wiring but also my first iteration of the camera mount/crash protection. The first couple of batteries were trouble free. Landings were rough but I was mostly taking things very easy, it was certainly a cool experience and all the gear performed flawlessly.
On the third battery I hit the ground quite heavily. Looking back at why I have realised that I basically flew it into the ground forgetting that maximum lift (i.e. quadcopter level) is going to be achieved with the camera pointing mostly towards to sky. When I came down I was looking mostly at the ground despite thinking I was pulling up. As can be seen below the airframe itself suffered no real damage. The motors all twisted on their tubes but that is easy to correct. Unfortunately one of the motors also came off its tube, the spinning prop cut one of its wires and pulled it out of the motor at the same time. The VTx also collected a lot of dirt given that it is exposed beneath the airframe. The roll hoop around the camera snapped as the quad tumbled, I guess this means it did its job of preventing the camera being a point of impact. All these factors combined meant that I decided not to fly with this cobbled together rig, I would wait until everything was in its proper place.
To address the wire cutting issue I have decided to route the wires through the tubes rather than hanging them loose around the arms. To achieve this I have had to redesign the motor mount. Previously the 2 parts of the motor mount and the motor were all clamped to the tube using the motor mounting bolts however the spacing meant that they could only just fit around the 12mm tube. This forces the wires to exit at 45° to the tube, in reality this would probably be fine but my sense of details told me to rotate them so the wires exit parallel with the tubes. To do this the new motor mounts incorporate their own M3 clamping bolts with captive nuts. To assemble them the top half of the tube clamp is bolted to the bottom of the motor (now using all 4 M2’s) before the two halves are clamped around the tube. The new mounts also include a slot on the end for passing the wires in to the tube.
As mentioned in one of my design posts the rear motor mounts now also incorporate a small pocket for LED tail lights. I haven’t designed the tiny PCB for that yet but the image below shows where they will be with the power supply wires hanging out. I’ve been really impressed with the detail I have been able to model in to these parts. The wire grooves through the middle of these are only 1.5mm wide but are reproduced in perfectly useable fashion without needing to make any adjustments to my default print settings.
At the rear the modified tube clamp for mounting the antenna has come up nicely but I may need to make a counter bore for the nut. The antenna itself is only just getting tight. All of the tube clamps are also modified on the inside with a hole for the motor wires to come through.
Underneath I am very please with the VTx housing. I completed the details of its design after receiving my Lumenier TX5GPro Mini 600mW (GetFPV). It now sits inside the housing with no extra support required and is protected by thick ribs on the inside of the housing. The wires will be routed through the PCB rather than coming out the front as in the photo below.
And finally the camera mount. There are a few pieces to the current solution but it allows for a lot of flexibility and feels much more robust than my first attempt. The camera is held in place by the clamping effect of the bolts in each side, it can be adjusted from 0° to 45° above horizontal. To install it the base plate is attached to the airframe clamping the two posts in place before the threaded standoffs are inserted and each side of the housing is clamped around the camera.
I also decided that the less conspicuous look of black was better than a big red blob on the front.
Next up is all the internals. I already have everything on hand so it won’t be too long before this is in the air.