Pencil mark and cut the 1/8" wide slot for the engine hook.
The instruction say to glue the two rings 1/2" from the top and bottom of the engine tube.
I don't think that offers enough flex of the engine hook when sliding in an engine.
I set the low centering ring 7/8" from the bottom.
Instead of 1/2" from the top of the tube -
The upper ring was set over the upper bend of the engine hook, approximately 1/4 from the top of the tube.
I've pencil marked the ring to show how the ring is centered over the hook.
This strengthens the mount.
The instructions have you tie a double overhand knot to secure the Kevlar under the upper ring. That thick knot might bulge the outer tube - not much room between the 20/50 rings and 1" diameter tube.
I rolled the Kevlar around the tube with the overhang tail twisted under the start of the line. The twisted Kevlar end is pushed into the glue fillet.
Yep, 1/2" doesn't feel like much room to allow the engine hook to be flexed -- especially worrisome with the standard hook that Quest used to use (which could easily be bent out of shape).
ReplyDeleteHi Naoto,
DeleteI did a dry fit of the mount in the main airframe tube with the centering rings 1/2" from either side. The Quest engine hook would have bent when sliding in the motor.
IIRC the Quest engine hook also had a somewhat shallow hook -- combined with the hook not being spring steel (so it's easily bent), would raise concern over the motor possibly getting spat out on ejection -- so perhaps a wrap of tape over the engine hook and motor rear end (to make sure that the hook end engages with the back of the motor) might be recommended.
DeleteAside from relocating the rear centering ring, a full slot slot could be cut from the centering ring (to allow for engine hook flex), then use a hold-down strap (strip of material cut from facecard material) to retain the engine hook.
Delete