I was going through my computer junk and came across this photo of a collective pitch rotorhead on an old hard drive that I’d completely forgotten about.
The main rotorhead bearing was a spherical roller bearing that allowed pitch and roll inputs much like a Bensen spindle head except the teeter bolt axis passed through the center of the bearing, eliminating rotor thrust feedback into the cyclic control system. Seemed like a good idea at the time but wasn’t.
The Bensen offset gimbal rotorhead feeds back a component of rotor thrust into the cyclic control system in a stabilizing direction that provides enough stability to permit some very unstable gyros to be flown.
Anyhow, I installed this rotorhead on a very unstable gyro and Ernie Boyette, David Seace and I managed to fly it, although very sedately, [IMG2=JSON]{"data-align":"none","data-size":"full","src":"https:\/\/www.rotaryforum.com\/core\/image\/gif;base64,R0lGODlhAQABAPABAP\/\/\/wAAACH5BAEKAAAALAAAAAABAAEAAAICRAEAOw=="}[/IMG2]
but it was a good learning experience about stability. This must have been 35 years ago.
The rotorblade thrust bearings were Timken tapered roller thrust bearings intended for use as king pin thrust bearings for heavy equipment.
The main rotorhead bearing was a spherical roller bearing that allowed pitch and roll inputs much like a Bensen spindle head except the teeter bolt axis passed through the center of the bearing, eliminating rotor thrust feedback into the cyclic control system. Seemed like a good idea at the time but wasn’t.
The Bensen offset gimbal rotorhead feeds back a component of rotor thrust into the cyclic control system in a stabilizing direction that provides enough stability to permit some very unstable gyros to be flown.
Anyhow, I installed this rotorhead on a very unstable gyro and Ernie Boyette, David Seace and I managed to fly it, although very sedately, [IMG2=JSON]{"data-align":"none","data-size":"full","src":"https:\/\/www.rotaryforum.com\/core\/image\/gif;base64,R0lGODlhAQABAPABAP\/\/\/wAAACH5BAEKAAAALAAAAAABAAEAAAICRAEAOw=="}[/IMG2]
but it was a good learning experience about stability. This must have been 35 years ago.
The rotorblade thrust bearings were Timken tapered roller thrust bearings intended for use as king pin thrust bearings for heavy equipment.