ZOHD Dart Extended Motor Mount

thingiverse

The ZOHD Dart is an excellent R/C airplane that I've had the pleasure of flying, although I did manage to crash mine twice in a relatively short period of time - once due to pilot error and the other occasion caused by a disconnected servo cable. Both crashes resulted in severe damage, with the motor breaking off the back of the fuselage. In the second incident, the plastic socket glued into the fuselage also broke, which led me to question the structural integrity of that particular area. Upon closer inspection, I noticed a sheet of plywood attached to the bottom of the fuselage interior just ahead of where the plastic socket is located. This observation prompted me to design and construct a replacement motor-mount that would distribute the loads from the motor more evenly into the fuselage foam. The new mount fits perfectly into the original plastic socket and uses the same screw as the stock mount for securing it in place. A 3mm hole needs to be drilled into the bottom of the fuselage for an M3x25mm screw, with the nut being captive within the mount itself. To ensure accurate drilling, I took advantage of the existing vent on top of the plane and used it as a guide. The design has been uploaded in two different variations - one with a 10mm thick mounting area, which is currently installed on my own plane, and another with a 3mm thick mounting area. While both designs offer improved motor-mounting capabilities, they do add weight to the tail of the aircraft. I estimate that the 3mm mount would require approximately 18g at the nose, whereas the 10mm mount would need around 19.5g. To address potential concerns regarding inter-layer strength, I printed the mount standing upright on my bed. Although I was worried about its durability, my mount has thus far withstood several hard landings and a few crashes while adjusting the CG (center of gravity). For added lengthwise strength, I glued a 1/4" aluminum tube down the center of the mount as an extra precautionary measure. If you're in need of a shorter replacement motor-mount, KevoFpv has an excellent design available on Thingiverse, while Yuki Kane offers a solution for mounting a 2206 motor.