What is the difference between the “knees” and “knee pins” on our Aero Center planes, versus what I hear people refer to as “torque links”?
Editor:
Knee pins and torque links are not at all the same thing. Knee pins are the vertical-travel pivot point between the upper and lower gear sections, as you are familiar with. The design of the gear makes it impossible for the lower section to rotate left and right; it can only go up and down.
On gear that uses shock struts (like most Pipers, and the majority of planes of all sizes aside from the light Cessnas and Cessna look-alikes), there is a shaft/piston that travels up and down inside an outer cylinder (often referred to as a “strut”). Unlike our sturdy Mouse gear, there is nothing in the shaft-and-tube design to keep the shaft (with its wheel and brake assembly) from spinning in the housing as it goes up and down. So torque links were born. Picture the letter “A”. Take one “A”, and put it on top of another “A”, with the top one upside down. The two “points” are pinned together with a bolt. The open end of the top “A” is bolted to the outer strut housing. The open end of the bottom “A” is bolted to the piston/shaft. All three bolted points are slightly loose, so that the upper and lower links (“A”s) can pivot at the bolt points. Now you cannot rotate the lower section (the piston/shaft) within the upper housing. The links are there to prevent the rotation. They are called “torque links” as they resist anything that exerts turning torque on the wheel assembly. Perhaps a better name would be “anti-turn links”. But on the other hand, while at the same time they resist unwanted turning, on a strut-type nosegear the torque links are also used to transfer steering torque from the steering mechanism to the lower gear section. I suppose someone could claim that the knee pin does the same thing on the Mouse gear, but that’s really a stretch. The gear design prevents the rotation; the pin is serving as a large hinge rod for the vertical travel.