REFLECTOR: Pitch Trim Mystery

[Scott Derrick]

John Dibble wrote:
> Scott - It took a lot of force and of course the farther I pulled back, the stronger
> the force.  It felt like I might break something.  I suppose you could trim your
> elevator all the way up and feel the force to pull the stick back to neutral.
>
>   
John thats exactly what I have done.  Sitting on the ground, trimming 
full down like I was in cruise flight, and then pulling on the stick to 
position the elevator in the 90 knot approach configuration.  It seemed 
like it took a whole lot of muscle, and yes it felt like I was pulling 
hard enough to break something.

It has made me appreciate the simple manual trim system as on small 
cessnas and other planes.  I realize they also may fail, but many like 
the 210 I fly has both electric and manual trim.  At some point on there 
is a single point of failure in the system though.

It would be interesting to see a study of failures in manual systems as 
in a cable from the cockpit to the trim tab vs. electric systems as in 
actuator located at the trim tab.  Which system has the higher incidence 
of failure or some type of faulty operation.  Of course the electric has 
the added dependence of  needing the aircrafts electric system.

Scott