ORIGINAL: Broken Wings
ORIGINAL: Champ-RCU
My 2cents.
DON'T SLOT ANY SPAR!!! THE MATERIAL YOU REMOVE DECREASES IT'S STRENGTH.
The spar slot tools from perma grit are not to slot the spar but the ribs were the spar fit into the rib.
Mark
I'll throw a nickles worth in.
Gee, I wonder why they call them Spar Slotters?
Spar Slotters -
Perma-Grit has re-introduced these very useful spar slotting tools in 3 convenient sizes.
These 6" long steel bars have the Tungsten Carbide course grit bonded to one side allowing neat, true slots to be cut into plywood, balsa or composite formers and ribs. Two sizes available, SP9C has been discontinued.
3mm or 1/8" #3c
6mm or 1/4" #6c
This guy knows a little bit about building models airplanes and he does the same thing...
http://www.airfieldmodels.com/inform...raft_wings.htm
A good read...
http://www.auf.asn.au/scratchbuilder/beams.html
The important part there is "true slots to be cut into plywood, balsa or composite formers and ribs" and NOT cut into the spars themselves. The slight notching into the spars he illustrates in his articles is very shallow and virtually cosmetic in nature. With a GOOD glue bond and the slots completely filled with wood from the web the spar will suffer minimal weakening. AIR does not strengthen.