The flying monkeys got me...

Helis and fixed wing

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Sunday, January 8, 2012

Thunder Tiger Hawk Completed

My T-pro MG90 servos arrived yesterday, and today I finished building the Thunder Tiger eHawk 1500. Building this thing was a pain in the ass. For such a simple airplane, it was a classic case of "its always something". I have never been a fan of single servo ailerons, though they are working pretty well on my Electrifly Cosmic Wind. On this plane the aileron connecting rod that runs from the control rods to the ailerons has a lot of flexibility in torque, and getting the control rods to connect to the aileron connectors was no fun at all. Some builders put individual aileron servos in the wings, something I may consider. Previous to this step was the attachment of the wing to the pod body (fuse). Builders have had problems with the blind nuts, especially the rearmost ones. I was no exception. I could not get the screws and nuts to join. I ended up using short wood screws. In the end, the surfaces move pretty much to their required limits, the CG is on, and she is beautiful!


Installing the ailerons was standard, CA hinges. The wimpy control rod is seen to the right. I think it would have been better for it to have gone to the middle of the aileron.



Small brass grommets protect the wood of the  wing at the four attachment points of the main wing to the pod. The back two had to come out as part of the bolt-nut fiasco.



The aileron control rod connectors. Not much range of motion, even screwed in a bit.



TheV-tail assembly was very easy and straight forward. Programming it in my Dx8 was easy: normal wing type, V-tail selected and that was it!



VERY tight space and tolerances for the control horns. The  upper one that runs horizontally is the aileron servo, and sits about 1-2 mm over the two elevator/rudder servos on a platform. The yellow tape on the back of the pod covers and levels out the epoxy I had to use to rebuild the back wing attachment. It still didn't work properly. I put tape on the front attachment base so that everything remained level.  I ended up putting a small s-curve in the aileron control rods to attach them to the ailerons without binding. This is wire I  made control rods from as the stock ones were too short. I think that the servo tray needed to be aft by another 3-4 mm (see black mark, should align with the top of the servo tray above the rudder servo), but it cramped up the elevator/rudder servos, which already were tight. In the process of creating the epoxy repair of the aft attachment base, epoxy ran down into the tail cone and bound up one of the elevator servos, which burned out before I figured out what happened. That's the servo I had to wait for...



You can see the s-curve I put in the aileron control rod. Using the stock standard clevis arrangement wasn't going to work unless I got them set perfectly and CA'd them to the control rods (they are not threaded), I had used Great Planes control rod quick connectors. This arrangement worked out pretty well.  I put white cote along the fuse to increase underside discrimination in flight. I also put some on the underside wing tips.



And so she is done! Motor spins, wings stays attached firmly, control surfaces move appropriately, and she really looks beautiful! I hope she flies without any squirrely behaviors!



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