Update 4/28/22: Adding pictures for the lower shell printed in Filaflex 60A! That stuff makes NinjaFlex seem hard. The downside so far is that overhangs appear to be quite difficult to get dialed in. Otherwise they came out great with 0.3 layer height. 2 walls/shells, 4 top/bottom, and 30% gyroid infill, leading to a very nice ‘bumper’ squish. Support removed easily and very cleanly. Just the overhang issue is present.
Update 4/12/22: Adding a one piece solid rear bar that will go from one mount arm to the other. Just to have the option for a simple rear bumper bar instead of a shell for anyone that would want that option.
I'll come back to add more later, but for now:
Both shell sets were slightly modified from two other sources. The mount arm and ring were designed by me.
Recommend printing each as they are oriented. I tried for best finish with least supports required. The top and bottom shell pieces were printed with either NinjaFlex 85A or Filaflex 60A. The mount ring, arms, & pegs were printed with MadeSolid Flex Solid 90A(maybe 95A). I would not recommend the use of harder than 90A materials as that would defeat the purpose of softening impact to the RC quads that cannot be easily repaired or replaced. Of course if it is for looks only and you expect no impacts use whatever you want. BONUS: if your quad pulls wheelies or flips over backwards the arms function as wheelie bars by themselves. (Doesn't prevent rollover to the rear diagonals though)
The shell 1 attachment pins could be printed out of nearly anything I think as they're just meant to help adhesion between the shell parts. Which, if printed out of TPU or TPE it is really really hard to glue together since TPU type materials are very chemical resistant. I have had good luck with Barge contact rubber cement, FoamTac contact adhesive, & high temp hot glue. In all cases the parts can be pried apart with decent force so I would not consider it a true permanent bond and may need to be reapplied after harsh use (bashing as well as kids picking at the parts). I also tried using a 3D pen to weld the parts with their own filament, but had negligible success. I was able to rip them apart at the weld seam easier than I'd have liked for the effort involved, so if you go that route YMMV. I'd go with the contact rubber cement as it's the best hold for ease of use.
Pictures of it in place on a Mario and Yoshi quad set will come soon…
Also check out the new front bumper!
https://www.printables.com/model/168356-carrera-rc-mario-kart-quad-front-bumper
The author hasn't provided the model origin yet.