Elevator Trim Linked To Flap Settings

[daleandee]

While reading an article from 2018 I found an interesting tidbit of information:

Most Sonexes are trimmed using the AeroConversions Trim System fitted to ‘NX, which uses a trim wheel and jackscrew assembly combined with two springs to put tension on the control stick. Basically, turning the panel-mounted trim wheel anti-clockwise adds ‘nose down’ pitch trim by applying spring-loads to the elevator circuit.

To trim ‘nose up’ simply turn the trim wheel clockwise. However, for UK-registered aircraft the LAA also requires the original elevator trim tab on the port elevator to be retained and linked directly to the flap lever, so that as flap is extended the elevator trim tab simultaneously and automatically trims ‘nose up’.

The last line of the second paragraph is intriguing. How would that be implemented? Setting the elevator trim for the flap settings in my Cleanex is not difficult at all (I have the manual trim lever). Perhaps a UK builder or pilot can comment ...

https://pilotweb.aero/aircraft/flight-t ... x-6288662/

Dale
3.0 Corvair/Taildragger

[Bryan Cotton]

From reading that I'd guess the starboard trim tab is linked to the pilot controlled lever, or there is no starboard trim tab and dial-a-trim is used. But it would be easy to implement, just a cable attached to the flap handle that would move the trim tab. Seems like a silly thing though.

The PA18 had the strongest trim change with flaps for any airplane I've flown.

[Area 51%]

Our 1953 Bonanza had a wicked nose down tendency while deploying the flaps. Nearly full up trim was required. A real drag during a go-around.

[daleandee]

Our 1953 Bonanza had a wicked nose down tendency while deploying the flaps. Nearly full up trim was required. A real drag during a go-around.

I agree, that wouldn't be good.

For these planes it just seems strange to me that the LAA in UK would have such a requirement. I don't find the handling characteristics to be difficult. I do know that with 30º of flap, full up trim, and 120 hp, a go around requires a good push to keep the nose down until it gets retrimmed but that's another subject.

I was curious as to how this is done by builders or if perhaps the factory gave some guidance on this for builders there. I think it would have to consist of an interconnect between the flap handle and the trim lever ...

Dale
3.0 Corvair/Tailwheel

[Area 51%]

There is a certification requirement within our very own FAA that a wing must be able to be brought up with rudder inputs alone. This is why a Bonanza has a spring loaded connection between the ailerons and rudder pedals.

And you all thought it was because Bonanza pilots were too lazy to use their feet in a turn.