Twisted: Week 54 - Rudder hinge

Hours to date: 490.0

Even though it was a Bank holiday I didn't get as much done as I wanted too on this job.

Saturday was a write off as I had to do my company tax. I did figure out a good way to remove the resin from the Ali tube though. Got one of my old blade razors and modified it a bit - the blades are quite soft and so don't scratch the metal at all. Worked a treat. The tube is all clean now and I've put two coats of release wax on it - so it shouldn't be a problem again.

Sunday was a nice day - so I had the garage door open and worked on the rudder hinge install. A bit of a scary job this one, lots of things have to line up.

With the integrated tailwheel there is an added complication as there is another rib at the bottom. I decided to do a 'dry run' by getting everything together in the right order to see how it all works before actually bonding or supergluing anything.

Before that though I did fit the top hinge to the tail. This was done with superglue to start with - just as well - as you will see from the below photo the pin in the rudder is off centre - by about 1mm. Actually the pin seems to be centred on the rudder seam, but the rudder itself is wider on one side than the other. This made it 'catch' a little on the fin when installed. I moved the hinge 1mm and this has helped a lot but as you will see from the below photo the fin goes in at one corner (other side is perfect) so this will have to be fixed. I intend to do this by putting several layers of carbon on the outside to build it up to the right shape. Then after that is set I will file off from the inside to give a good clearance. This carbon will need blending in with the rest of the fin - which will be done with body filler later on.

I figured out a good way to get everything lining up. One of the elevator pushrod tubes is just perfect for the job. Screw in a rod end at the narrow end and this allows it to hang from the top hinge. Get the fuselage levelled up and the elevator tube hangs straight down. The fatter part of which is only about 2mm narrower than the tailwheel tube. So it makes it easy to get it all lined up just perfect.

By doing all this it became obvious that the first important rib is the middle one - as this determines where the rudder connects onto the hinge pins. So get this one in the right place first - the other two ribs will be relative to that. (this will be the lower of the two ribs if you have the conventional tailwheel).

There are two further ribs that are missing from my kit - these are needed for the integrated tailwheel - one acts as a mud guard inside the rudder and the other more critical one makes the tail assume the right shape so that the tailwheel rotates freely and the rudder goes inside the tail. At the moment the rudder wants to go outside of the tail. I think I will contact the factory about this as I don't have any carbon spare to make up my own. Plus I'm not sure of the shape for the one that goes inside the tail.