33
« on: October 06, 2005, 01:41:45 AM »
Hi all - I'm new to the list (as a builder) and am searching for insight on engine mount hardpoints, extrusions, and the like for my 320-powered EZ-to-be.
In pure bass-ackwards fashion, I immediately purchased 1"x1" Al angle to hang my engine per the plans... THEN I selected an engine (non-plans 320) and bought some 1.5"x1" Al angle. Now, I have a pile of aluminum angle and a little voice in my head saying "Uhhrrr... maybe you oughta rethink this whole 'aluminum angle' thing."
After trading my bank account for extruded aluminum, I began wondering why the extrusion went from 1"x1" to 1.5"x1"? Was it based on some arbitrary comment made by RAF folks long ago regarding bigger engines? Is it backed up by any engineering/analysis? Why not 2"x1", or 3"x1"? Why not 4130 or another material? Then I thought "Hey! What sorta extrusions are the other non-235 designs using to hang their big engines?"
What I found was that the other designs (e.g. - Aerocanard, Berkut, Cozy) DON'T use Al extrusions. Instead, they use embedded firewall hardpoints and bolts in tension to hang their bigger engines. Embedded hardpoints, bolts in tension, a clean/updated design -- the voice in my head is pleased.
So... are there any "You gotta use Al angle because..." claims that I'm unaware of? Have any Long/Vari folks replaced those Al angles with hardpoints & bolts? Do any Aerocanard/Berkut/Cozy folks hate the hardpoint & bolt setup? Any tips/hints/specifics on the layup schedule on those designs? Should I be prepared to weld up a custom engine mount regardless? Does anybody need some aluminum angle!?? :wink:
D