Phase 5 - Fitting a DLG Throwing Blade
Throwing blade positioning is a personal thing and I am not an expert in this area, but the one thing I have learnt is "Forget aerodynamics, go for comfort" - adopt this approach and you will thank me in the long run!
1. First you need to shape your blade - personally don't invent the wheel and go with the SuperGee blade dimensions shown. The only difference with the FireFly blade is that it is curved - you'll want to fit that curve inwards so it hooks around your finger but DON'T. Think comfort and a clean release - and fit it so it curves towards the thrower. Either way shape your blade as shown.
2. Now cut the access hole for the blade in the wing skin - make it a tight fit and mask it off before cutting. Finally mask off the top surface of the wing so epoxy doesn't get on it.
3. Now fit your blade and get it to the angles shown. I suggest you angle it backwards if you throw first and second finger, or forwards if you fly second and ring (third) finger. Align it with your finger joints. Once you're happy with all the angles, CA it into place on the bottom skin.
4. Mix up a very stiff mix of epoxy and balloons, and inject using the straw technique - it will not flow but that's as it should be, don't bother trying to push it into every void.
5. One you've got enough epoxy/balloons in there, heat it gently with a hair dryer - the mix will soften and start to flow into all the voids and crevices. Add more mix if needed to fill the hardpoint to the wing surface. Once happy put it aside on a level surface to partially set.
6. Once it has partially cured and has the consistency of sold soap, carefully remove the masking tape being carful not to nudge the blade. Now tape over the top of the hard point with Sellotape (clear tape) and smooth flat to the contours of the wing using gentle pressure from a credit card. Work from the outside towards the blade on both sides. Once happy put aside to set fully.
7. Remove the Sellotape and clean up the blade and hardpoint. Now prepare for adding a 3oz glass patch to the wing's top and bottom surfaces by sanding them. Before you sand, mask off to the shape of the patch.
8. Cut your patch. The Photo shows 4 options but only 2 will work - Option 2 & 3 are OK, Option 4 is overkill and Option 1 is far too small and will fail as you must tie the blade to the spar with sufficient glass cloth. OK to cut and apply your patch, first glue glass cloth to baking paper using artist's spray mount, then cut it out to the size of the patch, spray a bit more spray mount where it's going to go and then lay the patch down and peel off the baking paper before wetting it out. Wet it out using Epoxy, do not use CA as it will definitely fail and rip your wing apart.
9. After the patch has cured, clean up any edges for comfort and check the strength of the blade.
That's it - and on to gearing up with some SD100 servos!
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