Electric Trim

[Jon Woellhaf]

The recent comments about the difficulty of setting electric pitch trim in a
Cirrus made me wonder if any electric trim systems use a design where the
trim speed is proportional to switch deflection. Are they all single speed?

Jon

[john smith]

In article >,
"Jon Woellhaf" > wrote:

> The recent comments about the difficulty of setting electric pitch trim in a
> Cirrus made me wonder if any electric trim systems use a design where the
> trim speed is proportional to switch deflection. Are they all single speed?

Trim motors generally run at the same speed as flap motors.

[Ron Natalie]

Jon Woellhaf wrote:
> The recent comments about the difficulty of setting electric pitch trim in a
> Cirrus made me wonder if any electric trim systems use a design where the
> trim speed is proportional to switch deflection. Are they all single speed?
>
As we were taught in elementary control theory: Never use proportional
control unless bang-bang doesn't work. Can't vouch for the Cirrus,
but I've never had any problem with single speed electric trim (either
in an Arrow or my Navion).

[Ron Natalie]

john smith wrote:
> In article >,
> "Jon Woellhaf" > wrote:
>
>
>>The recent comments about the difficulty of setting electric pitch trim in a
>>Cirrus made me wonder if any electric trim systems use a design where the
>>trim speed is proportional to switch deflection. Are they all single speed?
>
>
> Trim motors generally run at the same speed as flap motors.

Usually slower actually. Flaps move further and go stop to stop
faster in most planes I've flown.