Trim tab hinged.

Saturday 26th April 2008 (2hr 10min)

Bent and cut trim tab hinge pin. Trimmed and fitted elevator counterbalance weights.

Bending the hinge pin is not as easy as you would imagine. I marked where I wanted the centre of the first bend to be and heated the spot with a plumbers buthane blow torch until it was bright orange. By now the mark had dissapeared of course but I guessed that the centre of the heated area was the intended centre of the bend. Using my long -nose pliers, I grabbed the pin to the outside of what I thought was the centre point and twisted it over to create the tightest right-angle bend I could manage. it was surprising how much force it still needed and how quickly it regained its strength as it cooled.

Now, with the pin back in the hinge and the right-angled part hanging down ofer the inboard edge of the elevator, I marked where I wanted the centre of the next bend - about an 1/8th from the trim tab spar. Once again, the mark served only as an aiming point for the blow torch but the bend worked out just fine. It only remained to mark and cut off the unwanted tail and clean up the end on the Scotchbrite wheel. The finished item sits beautifully against the elevator trim spar.

I would like to have done as builders of other models have done and use one 'ear' from the hinge scrap screwed into a nutplate to hold the hinge wire in place. However, there does not seem to be enough space for the nutplate at the end of the trim spar on the forward side so I will probably have to just safety wire it as per the plans. I will leave this until later in case I think of some way around the problem.

The trim tab bottom skin's forward edge was interfering with the aft edge of the bottom skin and spar of the elevator, so I needed to bend this upward so that it just cleared this obstruction when the trim tab is deflected downward. I found the best way of doing this was to take the trim tab off and bend the entire length of the skin edge at the same time by pressing it against my bench.

I have heard of builders having problems in sawing the counterbalance weights because the band saw blade starts melting the lead. I saw no sign of this problem, maybe because my blade travels slower or because of the 16 tpi pitch. I did need to file some material from the top and bottom edges of the weights to get them to fit inside the flanges and rivets of the counterbalance arm webs. I hope this will not be a problem when it comes to balancing the elevators at final assembly. The weights are supposed to be too heavy so that material is removed rather than added in order to achieve balance.
I torqued up the nuts to 25 in-lbs and used Loctite to secure them.