Today, Fred came by again after being some months in Schotland for his job. As I am still hoping on temperatures over 10 degrees celcius to be able to prime my bulkhead parts, we were tackling some more small prep jobs.
One of those is forming and cutting the F773 tail cone skin.
The skin is pre-formed in the factory but you will notice that it does not fit the two aft bulkheads nicely. You will need to bend it more to match your bulkheads.
Believe it or not, this is a painfull process that takes a lot of time.
The skin is very thick here as this is an area that catches a lot of stress (tailwheel mount).
To bend these thick skins is very difficult. I used the same technique as with the bending of the elevator nose but soon found out that this didn't work really well. Used clamps, wood blocks and a lot of force. finally tried to massage it with the hands and came to a point (after three days messing with it) where I could be satisfied.
Next step after bending is to cut out the back portion of the tail cone skin where the tailwheel fork will pass through. DWG27 guides you on your path for this task. I copied the plan 1-1 and cut it out to be used as a template on the skin. Then used this as a rough template.
Initial rough cut made
From there, we used a cutting bit in the die grinder and sanding drum in the dremel to get closer to the wanted shape.
While Fred was finishing it off, I started making some more parts for the fuselage assembly. What's done is done...
Then we tested the tailwheel fork in the tail cone assembly.
After some fine tuning, I think we came to a nice result and a good fit. The side skin does not touch the end of the fork anymore but the fit is thight.
I'm still not sure if I will drill the tailwheel fork assembly now to the bulkhead (after priming) or if I will wait until the assembly is rivetted.
Fred tells me to wait because he had to reorder some parts on his plane as the tailwheel was off 6 degrees when he final installed it. on the other hand, Vans tells you to drill it now, they probably also have a good reason why... so will study some more websites before I move on on this one.