Over the past week I have been preparing the wings for joining. I’m a bit anxious because I’ve never put together one of these wing tube guy’s before. So I foamed the tubes by taping one end shut and pouring the foam in the other end and waiting for it to expand. I do this buy pouring in just under what I think will do the trick into all three tubes then let it expand and they all did not over flow with the first fill. Then I mix up more and top them off one at a time, letting any excess drip on the floor. Don’t get this stuff on your cloths it sticks like glue. I’ve included a couple of pictures of each tube directly after the foam hardens, and then again after the foam has been trimmed.

Next I pealed the covering up where I plan to glass. If I included that pic you can see which side I worked first. I started by lifting the covering that had been bent over the center section with a x-acto knife. This lead to many unintended cuts and other damage to the covering. So I switched to a putty knife, one I use for grouting in windows (is grouting what it’s called), about an inch wide and it worked much better. Then I made a 1.5-2 in span wise cut on either end of the covering where I plan to stop the glass. This would allow me enough free play in the covering to push the putty knife under and free up the covering in the area where I plan to peal it back.

I need to be able to run the A, F servo extensions so I ran string or wires. I use Airtronics 731 servos of early 90’s vintage in the ailerons so that I can cut the leads and run one wire from left to right A. Then strip the part of that wire closest to the center and attach one connector there. The age of the servo is very important here because some time in the mid 90 everyone cost reduced there servos and removed the terminating resisters. This is something I was told by an EE and it seams to hold true so I continue to do it. Anyway the purpose of a terminating resister (TR) is to eat up the extra charge in the signal line that the transistor does not use. Without it the unused charge bounces back down the line and is eaten up by the of the other servo’s TR or the RX’s TR. In the mid 90 all the manufacturers decided redundant TR’s were to costly and removed them from the Servo’s. That works fine until you put a Y harness in. With a Y the excess signal has a choice to go to the RX or the other servo thus causing those jitters we sometime see in long Y’ed runs. Again I’m just repeating something told me by someone who would know what they are talking about and really am not qualified to offer any advice or opinions. All I know is that by buying a buffered Y when this does happen, it eliminates the problem and the EE took one of them apart and verified that they were terminating the signal line.

The flap servos I’ve used are new and in the 125-175 in-oz range and I don’t have the servo stall calculation handy but for flaps I usually pick the servo to stall at 45degrees at twenty MPH below max. speed If there is any interest I can go into how this was done but I’m going to leave this here for now. So I may need a buffered Y for the flaps, only time will tell.

Lastly I fit the tubes in the wing and joined them as a trial fit. I was very happy with the tightness of the fit, and the lack of flexibility once everything was joined without glue. There is a stop at the bottom of each tube in the wing so I’m supposing that a two peace wing could be done. But not with my lack of experience here.

Joe