Tail Spring Arch Template

[Steve Pierce]

From Andy Anderson:

The Tail Wheel Spring Template available here is one I used to obtain more correct caster to the tailwheel on my Piper PA-22/20. A good spring shop can accomplish the re-arching using this template. The template was drawn from a rearched spring leaf, the lower of the four leafs in the PA-20 spring set. The arch was traced along the upper surface of this leaf. The other three leafs of the spring were patterned after the the bottom leaf after it was re-arched. When the spring shop is re-arching the other leafs, it is important that he match the arch of the lower spring as they are positioned with reference to the fuselage mounting hole ( the fwd hole ).A ruler scale was annotated on the original tracing to assist in getting the correct size print out to use as a template. You will likely have to blow up the "jpg" file by some amount to get the ruler scale to line up with an acutal ruler. The other thing that could be done is measure the angle change between the fuselage mounting end of the tracing to the tail wheel mounting end. Make a template with a smooth curve such that the change in angle between the start and the end is similar to this sketch.The re-arching is done in a major size press. The spring leafs are placed in the press at various and evenly spaced locations along the leaf to get a smooth increase in the arc. The arc is changed gradually with each interation to produce a realatively smooth arch. The spring steel should not be heated as it will change the spring properties.tailwheelspringtemplate.pdf

tailwheelspringtemplate.jpg