Monday, March 5, 2012

Willow build log #3

Well, Last time I stopped the build log at the moment to glue in place the inner nose with the ballast tube. This operation needs some preparation to garrantee a good positioning and aligment of the nose. I protected the parts with some transparent tape, them insert the inner nose in the nose cone with a thin plastic film in between. the fixing area of the inner noe is in fact a layer of rubber. According to the designer this is great to absorb the shocks and can still be glue with epoxy, the wood tray embrassing the ballast tube providing a deep and solid fixing into the fuselage. I used 10 minutes epoxy for this operation, then immobilized strongly the parts with more tape while drying to avoid any dis-aligment.

Lets start with control rods and servos installations. Control rods are made from 2.5mm quicklink with a metal clevise soldered on one side, and a second clevise screwed and glue on the other end, the glue is to eliminate any slop on the command. The rod is rigidified with a small piece of brass tube of the right diameter and length. All these operations are made "in situe" with the (soldered) clevise connected on the surface control horn, and with the servo in place (but not glued yet) with the servos arme at the right position, taking into account the servo travel, different between flaps and ailerons). When everything is fine, I have installed the wiring harness, connected the servos to it, then glued the servos with a kind of sealant (100kg/m2) which, once dry, can be removed with some technic. To finish the wings, I adjusted a bit the servos covers and tape them.

Let's return to the fuselage. I installed then the wiring harness in it. the routing of the wires is going under the servos tray, which is a bit acrobatic to rout, but feasible. You can decide to do the routing before gluing the servos tray. I then installed the elevator servos, cut the snakes at the right dimension, and install the 2mm adaptor for the elevator clevises. I'm a fan of MPjet plastic clevises on the servos side, as they have no slop at all.

The receiver is a JR Propo RG831B DMSS, 8 channels, and the battery made of 4 eneloop XX cells (2.5A). Because I needed lots of lead to obtain the right CG, I had to rework the front of the servos tray, in order to move backward the battery, and let more space for the lead.

I ended with a flying weight of 2480g. The willow is now ready, and at the time I'm writing these lines, I already flown it :)  so stay tuned for the next chapter !

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