Q-talk 127 - Condition Inspection Report
- Category: Q-Talk Articles
- Published: Wednesday, 23 December 2009 16:24
- Written by Jon Finley
- Hits: 1629
During my annual condition inspection, I found that my aileron and elevator bushings were more worn than I deemed acceptable. A fair amount of play existed in both the mid-span and outer end bushing of the elevator. Jim Patillo had made a comment a year or so ago about using Rulon bushings on his Q200, so I decided to investigate. I am certainly not a materials engineer, but I did some research and found that Rulon appeared to be a good option. After completely disassembling and cleaning my control system, I inserted the Rulon bushings with red locktite and applied a very small amount of white lithium grease to the pin and inside the bushing surface.
1 purchased the Rulon bushings from McMaster.com. Specifically, item 6627K13 (HIGH-PERFORMANCE PEEK FLANGED SLEEVE BEARING, FOR 1/4" SHAFT DIA, 5/16" OD, 1/4"L, 1/2" FLANGE -$3.82 ea.) 2 for Elevator, 2 for Aileron and item 6362K212 (RULON LR SLEEVE BEARING, FOR 3/16" SHAFT DIA, 5/16"OD, 1/2"L,7/16"FLANGE - $1.80 ea.)2 for Elevator Mid-Span Pivot.
While the elevators were off, I discovered that the mid-span pivot pin was slightly loose in both elevators. Reaching the nut on these pins is easy to do with a very long 1/4" drive socket extension. However, I could not get the socket to grip the nut well enough to tighten it. After trying everything I could think of, I finally painted the outside of a socket with a black marker and gave it another try. The marker had been worn off the tip of the socket indicating that there was interference. So, I dropped a socket in the lathe and trimmed it down to a very thin wall thickness. This turned out to be the trick and I could then tighten the pivot pin nut.
I am very happy to report that with the pins tightened and with the Rulon bushings installed, all the play in the pivot points has been eliminated and the control movement is very smooth. I have flown a couple of hours with these bushings and could not be happier. Obviously, this is an unproven installation, so I will be watching it closely.
By the way, I really want to say thanks to Sam Hoskins for the condition inspection checklist that he has created. I modified it slightly for my airplane and found it to be very helpful. Thanks Sam!
Gas shock replacements
I have struggled with the "right" gas springs for my forward tipping canopy. The original kit springs had leaked down to nothing and were worthless. This resulted in a canopy that has smacked me on its way down more than once. Let me tell you, that little steel alignment pin on the canopy frame impacting your skull provides a memory that will not soon fade!!
After recovering from my last "encounter" with "the pin", I decided it was time to do something other than take after my canopy with an axe. So, I ordered two 80 lb springs from McMaster-Carr. I found that just one of these springs was about right. However, on my two spring installation, all of the load was on one side. So, being the "mathematician" that I am, I did a little calculating and figured that two 40lb springs would roughly be the equivalent of a single 80lb spring. These 40lb springs are McMaster-Carr item 4138T534 (GAS SPRING WITH BALL-JOINT END FITTING, 40 LB FORCE, 9.65" EXTENDED LENGTH, 3.54" STROKE) and are $16.59 each. The 40lb springs are now installed and work nicely. I think that two 45lb springs would probably be perfect (for my canopy). These springs are a perfect replacement for the springs provided in the the forward hinged kit from QAC.
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