Posted for "Bay Elliott" <bay@farwellgroup.com>:

Hi Marv,
I am a relatively new Legacy builder (last 6 months) and I am not familiar
with the Reichel Trim Wheel.  What are the advantages of this system over
others and is it applicable to the Legacy?

Warm Regards,

Bay Elliott
Executive Vice President, The Farwell Group, Inc.
Executive Recruiting Consultants
(305) 529 4811      bay@farwellgroup.com

[I thought I would move this out onto the LML to invite further discussion and get some assistance from folks who know more about the intricacies of trim systems than I do.

The earlier LNC2 was designed with a trim system that used a spring bias applied to the elevator pushrod to control the overall elevator position. It was controlled by a small cruciform trim lever that moved the biasing springs forward and aft. Dick Reichel invented his trim wheel to replace the lever, allow finer and more precise trim adjustments, and to provide folks with the same sort of trim wheel that they had flown with in any number of certified aircraft.

Trimming the location of the entire control surface is probably aerodynamically preferable (less drag) to moving a trim tab to use the airflow to move the control surface, and the removal of the trim tab eliminates its weight and complexity, as well as those of the servo motor and linkages... ie, less counterweight required for balance. There are probably other aero issues, but I leave those things to folks more knowledgable than I in these matters.

Whether or not a a spring biased trim system would be applicable to the Legacy, I can't see why not, at least for those folks who are still building and can opt to incorporate it into their control system... I don't know how the trim tab is built on the Legacy elevator, but if it's cut from the elevator similarly to the method used on the LNC2, that part of the process could be bypassed and the work, weight and complexity of the trim tab mechanism could all be left out. To my knowledge no one has incorporated this into a Legacy, but that doesn't mean that it couldn't be done.

The only disadvantage with the spring bias system at this point is that it is totally manual. Once I finish with the basic trim wheel system I'm going to look into motorizing it while still allowing manual adjustments.

<Marv>         ]