Given the inadequate nature of the stock landing gear that came with the UAir R10 quadrotor that I backed on Kickstarter, I’ve had a go at making my own from the remnants of the original shock absorbers.
I’m not sure quite what the original ones were designed for but they were flimsy, far too short for use on grass and compressed completely under the quad’s own weight, leaving nothing in reserve for absorbing the additional force of of a hard landing.
After one of the damping cylinders was seen to depart in flight and another one had become distinctly crunchy in its limited range of movement, I decided to build a longer set from what I had to hand.
The original shock absorbers separate into two parts – the damping cylinders themselves and their T-shaped mounts that attach to the frame side pieces. I used the T-shaped mounts to attach my landing gear.
Having said earlier that I’d used what I had to hand – well, that turned out to be an old fibreglass tent pole and two plastic coated wire coathangers. I knew there was a reason I’ve been keeping a box with hundreds of old coathangers in the loft for the last 7 years… it was to make a set of landing gear out of the only two matching ones in the whole tangled mess!
The tent pole was cut into 14 cm lengths. The length was merely chosen to maximise the use of the pole, not because of any particular ground clearance requirement. After cutting, the 14 cm lengths were wrapped in electrical tape to give a snug fit into the T-shaped mounts. For easier identification of the quad’s left/right, I wrapped red and green tape around most of the length of the legs.
Now, the new legs were plenty long enough at this stage but I decided to go a bit further and add the coathanger pieces to make proper skids. Fortunately, the tent pole was hollow and it’s 4 mm internal diameter matched perfectly with the diameter of the plastic coated wire coathanger.
Some careful bending of the coathangers was required to get them symmetrical and also to ensure that they did not exert a bending force on the tent pole sections, and hence didn’t deform the quad’s frame.
The quad stands quite tall now and could easily accommodate an underslung payload or land in fairly long grass without becoming a lawnmower. I may shorten the fibreglass pole sections in time, but given that I only had one pole, didn’t want to cut them too short to begin with.
The coathanger heritage of the skids is clearly visible in this side view!
You can see the problem I had with how short the old landing gear was given that the skids are almost hidden by what is short, freshly cut grass – the quad really was down in the weeds, the wet and the chicken mess before.
So, does it work? Well, upon throttling up just after the last photo was taken, the quad suddenly executed a back-flip and snapped two motor shafts… so I can’t test further until I track down some new motors or spare shafts.