Monday, January 25, 2010

Control Surfaces- Active!

Tonight I covered the elevons with 3M "Extreme" packing tape. The elevons went from being super floppy- basically no torsional rigidity at all- to being reasonably stiff. At least I think they'll be stiff enough to work. I attached the elevons with 3M Blenderm tape. When I connected the servos to the surfaces using some old control horns from an old gas model, I cut the horns down to use the most aggressive hole. After I did this I realized the disadvantage- this hole not only gives the most surface travel vs. servo travel, it also gives the most slop. I'll have to watch this when I build the 'real' speedwing.




I tested the surfaces, and verified they were moving in the right directions. The elevator / aileron mixing seems to work well. This model should have plenty of control authority!

 

After using a dremel to core out space for the ESC, receiver, and various hook-up wires it was time to verify the CG is still ahead of the neutral point.  I tried balancing the wing using a 2200 3s, a 1050 3s, and a 2150 4s. All appear to work assuming that the battery has to fit within the boundaries of the wing. Note the batteries are all pictured in approximately the location required to have the CG just ahead of the neutral point (NP).

 
 



Finally, I attached a 9x6 APC E prop to try out the motor. Even with the 3s battery it seems to have a much greater than 1:1 thrust to weight ratio. Provided the wing is controllable it should be a blast to fly! With the smaller batteries it should also be a good floater.

I'm rethinking my initial plan of not adding any spars or reinforcement except for external packing tape. After I core out enough material for the various battery options there isn't going to be much left at the wing root. I haven't yet decided if I'll add simple carbon spars, or else cut some plywood spars to join the two wing cores across the battery cavity.

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