ORIGINAL: denney47
I use long stand-offs on my gas airplanes (3") but the stand offs I use are threaded on both ends so you use two short bolts per standoff instead of one long bolt.
Tom
Valley View RC
Yeah I was reading on many other threads that long bolts & spacers are a BAD idea as the engine puts an lot of torque on the bolts causing them to eventually rip out.
A hardwood plate or base with short spacers was suggested, so this is exactly what I did.
I created a "U" shaped 1 3/4" spacer block to which I've adding short standoffs.
As suggested this creates a wide area to distribute engine torque and the U shape prevents lateral movement.
In addition to blind nuts I have a set of wide washers and lock nuts behind the blind nuts behind the firewall.
I'm still a bit worried about the gear mounting area.
The gear attached to ply that is in turn glued to the formers.
The ply looks too thin to me....
You can see this in post #3 above.