Tonight I started on installing the Ray Allen POS-12 position sensor to detect the flap position. This involved the position sensor itself (hard to see in this pic, but it is at the top of the rod), some model airplane pushrods and connectors, and an adel clamp connected to the flap weldment. Here it is in the up position. Notice that Adel clamp on the flap weldment is as far aft as possible.
And in the down position. It took a little trial and error to get the pushrod to the proper length. At first I decided to take the mathematical route. I measured the angles the flap weldment was in its up and down position, then I measures how much the POS-12 sensor traveled. All I needed was to form some equations and toss some sine's and cosines in the mix right? Well, this beast of a math problem evolved into a very large quadratic equation that even my most evil engineering teachers in college or grad school wouldn't give us even for extra credit. So I took the quick approach of trial and error.
Here is the details of what connects to the flap weldment. It is a DG16 adel clamp and some 063 adapter to get from the #12 hole for the bolt to the #52 hole the pushrod end interfaces to.
A side view...
And here are all the juicy details of the part numbers needed. I bought all of the pushrods and couplers from TowerHobbies.com. Here is the complete part list and Quantity:
TH = Tower Hobbies
GP = Great Planes
Quantity TH Item # GP Part # Description
-------- --------- --------- ---------------------------
1 GPMQ3831 LXK088 THREAD COUPLER 2-56(0.074")
1 GPMQ3750 LXK064 THREADED PUSHROD 2-56X12"
2 GPMQ3791 LXK077 STEEL CLEVIS 2-56
And here is the real magic -- 10" was the money length for the pushrods (before the coupler was soldered on) so the full flap travel utilized the entire travel of the POS-12 position sensor.
Last Modified: March 21, 2021