Comparing control system friction

[ARietz]

Hi All
In the design of an LSA, I'm looking for a method to calculate the total friction of a flight control system, given the total system geometry, loads, and bearing materials used, etc. At a previous employer we had a copy of "BDM-1606, Boeing Design Manual, Mechanical Controls" that had a nice, reasonably accurate method of doing that, but I don't have a copy at my new employer. Does anyone have a copy of BDM1606 available, or know of a similar method of calculating mechanical friction?

 

[tbuelna]

ARietz,

While the basic kinematics in a (presumably) mechanical linkage system is a fairly straightforward problem, establishing the mechanical efficiency of the overall system is a bit more sticky. Determining the actual friction at each joint/interface is critical, and these values can vary greatly due to things like temperature, wear, misalignment, assembly/manufacturing tolerances, etc.

Try a search for relevant documents here:

http://www.dtic.mil/dtic/

Another good reference is the Helicopter Design Manual AMCP 706-202:

http://handle.dtic.mil/100.2/ADA033216

Good luck.
Terry