Chapter 17 – Pitch Trim Update

The Atkinson Pitch Trim System project marches on!  After receiving new parts and materials, Marco has machined some simply beautiful spring housing assemblies. Which, speaking of springs, they seem to be the most problematic part of this whole endeavor.

Chap 17 - Atkinson Pitch TrimChap 17 - Atkinson Pitch Trim

When Vance designed and built this pitch trim assembly back in the 1990’s, apparently both True Value and Ace hardware stores carried a spring known as “Compression Spring p/n 196.”  Well, after emailing, calling and perusing a half-dozen True Value and Ace hardware stores–and those big Blue and Orange guys as well–for those of you that are interested, I can assure you that that spring is no longer in their inventory.  Nor anything close to it to serve as a suitable substitute.

However, after one Amazon & two Century Spring Co. orders for springs (I won’t bore you with Century Spring’s minimum order amount), it looks like we finally found a suitable spring, and possibly one viable candidate . . . subject to testing of course.

Chap 17 - Aktinson Pitch TrimChap 17 - Atkinson Pitch TrimNow that we have a viable set of springs, and can use those specs to narrow in our search for some springs that let us lock in our control forces (FYI – Vance had three sets of springs [that fit!] that he tried out before getting the right “feel” on the pitch controls).

Chap 17 - Atkinson Pitch TrimChap 17 - Atkinson Pitch TrimIn addition, I’ll be ordering the actuator this week so that at least initial testing can begin, which will help in selecting some further spring candidates.



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