Rc-Warehouse-USA

My Feedback: (28)

How do you figure the placement of the root and tip templates on the foam block? I am cutting wing cores for a 33% extra 300.


Thanks for the help

Ed Smith

Assuming the finished wing will have balsa L.E. and T.E. the foam block will be cut to the shape of the wing planform less the width of these two items. the block will look like a half wing panel chordwise, spanwise and with what ever taper the wing has. Depending on the style of template used they will probably have the front of the block and a chord line marked on them. Line these up with corresponding marks on the block and hit the switch.

Ed S

combatpigg

My Feedback: (3)

Hi QUICKSAND! The EXTRA wing has alot of taper and it can be cut from a single pivot point, with about 10 feet of wire. I set the pivot point up on a vertically mounted 1/4-20 bolt that has a fender washer sandwiched between a couple of nuts. the fenderwasher has a small hole drilled off to one side, this is where I tie off one end of the hot wire. You have an infinate height adjustment with this setup to get the wire centered on your templates. The pivot point is set up just inside the imaginary convergence lines that can be drawn where the L.E. meets the T.E., this will make the wire track the outboard template automatically while you concentrate on the inboard template. You want to stagger the foam blank slightly so the outboard template is touched by the wire before the template nearest you is touched, this will ensure that the wire tracks around the outboard L.E., instead of doing a U TURN, and heading back home . I start at the UPPER T.E. and go completely around. I square off the blunt L.E. and T.E. cuts by leaving the airfoils in their wing saddles and doing these cuts at my table saw.

Rc-Warehouse-USA

My Feedback: (28)

I do not understand how you are doing this can you upload an image so I can follow your instructions? This will be my first atempt at foam cutting. I have already cut root and tip templates out of wood for the hot wire to follow.
Thanks Quicksand

Flypaper 2

Quicksand:
you really need to make your templates out of Arborite, the counter top material, as it will take the heat. The heat of the wire will dig into the wood and stop the wire which will leave a groove in the foam. Try a place that installs cupboards and counter tops. Their scraps work fine. After you cut the templates to shape, sand and polish the edges to a fine finish as you don't want the wire to catch. A good idea is to test it on scraps first to find the right wire heat and no catches on the templates. Good luck and let us know how you make out.