Monday, March 10, 2014

Dream Flight Libelle assembly

As I always do different from the assembly manual, I started by the fuselage. First of all, I glued the pastic control horns on the rudder and the tail. As there is a recess, you cannot be wrong. I used medium type CA from R&G. I use cotton bud to wipe away excess glue.

Then I fixed the tail in place with the plastic screw to have a reference, then glued the fin in place on the boom with a quick check using a 90° square. I didn't add the small piece of tape overlaping onto fin as mentionned in the manual. I don't think it is needed.

Next step was to install the elevator and rudder servos in place. I used 4 x Power HD DSM44, metal gear, digital servos I had for a while for another foamie project. Being a bit higher than the recommended HS-35HD, I digged a bit the foam, till the plastic shell in skid. Servos are glue using some Uhu-pore neoprene glue. Now we can install the pushrods. The shorter one is for the elevator, the longer for the rudder. The Z-bend end is on servos side and the clevis is on control surface side. The celvis is asymetrical by design, so has an orientation, screw head on top for the rudder, screw head on right side for the elevator. screw the clevis, but not too firmly yet on the carbon pushrod, install the pushrod into the boom, connect on the servos, then plug the clevis on the control surface, and adjust the clevis position before to tighten the screw on the clevis.

In install the receiver on its side in order to have the ailerons pin (channel 1 & 2) accessible. I did a small extension from the receiver to the batterie, no switch. Some small pieces of EPP or hard foam are cutted to immobilize component.

Let's start with the wings: As indicated in the assembly guide, gluing the 2 wing panels together is the most delicate operation. First, I glued the 2 dihedral brace in place by applying some medium CA to recesses, then put the braces in place. Same operation for the second panel, except that you need also to apply CA on the root face areas. This is the step where you need to by quick, precise, and not dirty if you don't want CA everywhere. Medium CA allows to have few seconds to position the 2 panels together. Once done and dry, you can glue the center wing plate located on the upper side center.
Before to install the servos, I glued the control horns (same as rudder and elevator). The ailerons servos being a bit longer thant the recommended ones, I remove some foam before to glue the servos in place with the arm in place at the correct neutral position with some Uhu-pore neoprene glue. Then I connected the wire extensions and installed in their channels. I used some blenderm over wire channels and servos. Like for the rudder or elevator, the pushrod provided are already at the correct lenght, with a Z-bend end to connect on the servos arm, and a plastic asymetrical clevis to connect on the control horn. Just left he launching peg wich is a small piece or carbon tube you need to sand before to install. Several attempts are needed before you have sanded enough for the tube to be install firmly.

Let's finsish with the balance. I neede 20g of lead (5 gr under the battery, 3 x 5gr on the side of the battery) to obtain the CoG at 5mm behind the carbon spar, which correspond to the rear limit indicated on the assembly manual.

Balanced, my Libelle is 275g. I added few strips, that are painted with specail Elapor spray. It adds good visibility in flight.

Overall the assembly went very well. No bad surprise, everything is carefully designed, clever, simple. It is a pleasure to build kit like this, when you don't need to replace, rethink things.

Next time, I will do the maiden flight report. Stay tuned !

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