J430 Trim

[Captain]

Brent. I see little risk with what Ian has done as long as the material is similar to the original in nature and thickness as the pull is in the same direction. + the elevator cable is still acting on the same point of the elevator. When I make one I'll fabricate a copy then mail it down to you, and see if you are tempted to fit it. I reckon there is much more risk of sheering off one of those spring retaining split pins in the trim mechanism than Ian's bracket failing. Regards Geoff

 

 

[Guest brentc]

Fair enough, however this is the bit that scares me the most.......

 

as long as the material is similar to the original in nature and thickness

I'm happy enough with mine and there's probably more I can do with the spring before I make this change, but if you're in the mood for cutting me a copy, please do.

 

 

[ianboag]

In my first effort, I reconnected the elevator rod to the top hole rather than the bottom. Whoops. It flew OK but there was no need for that. I have rectified that mistake. Finally - I trimmed the bracket down a bit - did it with a jigsaw in situ - if I'd been a better workman I'd have taken it off, radiused it all nicely, buffed it up and painted it white ...... maybe one day. It is made of aluminium of the same thickness as the plate it replaced (about 3 mm). I don't know about the grade but it is not a highly stressed part.

 

I looked up the build instructions for the J200 - my suspicion about the trim lever pivot position was wrong - the instructions clearly say it goes in the back hole and the trim lever travel is not symmetric (goes forward about twice as far as it goes back).

 

FWIW - on the ground - the "horizontal flight" position on the elevator is with the counterweight about 3 mm above the elevator top surface. I was talking about all this to the agent and he confirmed that - it's why he moved the cable clip at the rear because the trim mechanism "as built" did not get there.

 

 

 

 

[ianboag]

I'm not trying to teach my granny to suck eggs, but here's how I figured out the position for the rear hole in the bracket. I disconnected the trim from the elevator, moved the lever to a central position and clamped the elevator in "level flight" position. I had figured that out earlier by putting the lever in the known level flight position and seeing where the elevator ended up.

 

This is what it all looked like ... required bracket shape is pretty obvious. You can see why I thought about shortening the spring rod as an alternative too.