Elevator Trim Control

A forum about all aspects of the construction and maintenance of the original Hatz CB-1 biplane. Here is the place to ask your questions and get the answers from the real experts.
cl30captain
Posts: 7
Joined: Wed Aug 11, 2021 5:07 pm

Elevator Trim Control

Post by cl30captain »

I just brought my new-to-me CB-1 home and realized pretty quickly that the trim has a tendency to move into the nose up position. What are you folks doing for elevator trim that works and doesn't have a mind of its own? My setup is a push/pull cable on a lever similar to a throttle. It has a basic friction lock but it doesn't seem to do much.
Mike
Dallas, TX
CB-1 S/N 803
1948 C-195
hatz215
Posts: 110
Joined: Tue Mar 23, 2010 3:29 pm

Re: Elevator Trim Control

Post by hatz215 »

Mike,

If it's built to plans it has a Mercury outboard motor throttle control for the trim cable. Make sure the clamp holding the control under the elevator is tight and not slipping. If it's tight, I can't imagine a good friction lock not holding.

Steve
User avatar
Dana
Posts: 84
Joined: Mon Aug 06, 2018 6:51 pm

Re: Elevator Trim Control

Post by Dana »

I've never looked closely at mine because it has never given me trouble. The lever is aluminum plate, maybe 3/16" thick, and the friction lock, from the only picture I have that sort of shows it, looks like a leather washer sandwiched on either side of the lever. I think the pivot shaft is just a bolt with a wingnut to adjust the clamping force. It is very sensitive, though, and I have to watch that I don't bang it with my knee (I plan to mount some kind of pad to support my knee away from the knob).

If it always wants to move to nose up, it could be that your normal position is somewhat nose down, so you might be a bit tail heavy or the stabilizer incidence isn't quite correct?
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