Monthly Archives: September 2012

Status Report

Beefed up the bottom frame with two of those angle braces for each roll actuator and an extra 2.5″ of wood mostly to raise the actuator up.

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Roll actuator U-joints are upgraded with coupler nuts (much cheaper than the 3/4-10 rod clevis route).

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Waiting for the weather to improve and waiting to get some free time so I can install these bad boys.  I got the 24VDC PSU from China and tested it so I will be installing him permanently in the avionics compartment when I take the topsoil off again to access the right roll actuator U-joint bolt.

Not sure what I am doing with the springs yet… not sure if these beefy actuators will fit up the middle now!

Bidding on an 5850 Eyefinity 6 card so that I can test the frustums, angle offsets, stencils, etc over the winter.  Waiting for an answer from ATI about the 2×2 plus 2 extended configuration (mixed mode).

Parachute Retainer

First, I apologize for this “focus” effect – my camera was in a weird setting.

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Side by side you see the F-4 (Mk.7H) left and F-8 (Mk.7F) right.  The only difference is the inertial reel charge attaches to four holes on the left side when looking from the front.

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I measured down 3 3/8″ from the top for the first row of holes…

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And 7 1/2″ for the second row of holes.

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Then from the left the top two holes are 2 3/4″ and 3 1/4″

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And measured from the inside was 2 3/4″ and 4″ respectively.

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Finally, the hole size is 1/4″

Replacing Roll Actuators

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Removed the old right-side actuator (bottom) and was measuring the difference in length (the old one was 21″, the new one is 18″ but the difference because of the tang is 2.5″).  The new ones are 3″ bore (the old ones are 1.5″ bore) which will yield 4x the force thanks to our friend pi*r²!

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New Actuators

Received two of these Allen Air 3×18 LF units from eBay Tuesday.

I got around to testing one of them last night and there is a lot of air leakage under 50 PSI.  I wrote Allen Air’s engineers and they wrote back:

O-Rings have a Shelf Life of about 15 years. In a cylinder it could be less due to compression set. The O-Ring will flattens out on the O.D and the I.D. This happens when the cylinder is not in use. There is a date code on the cylinder #106. The cylinder is 6 years old. All you may need is a packing kit #A3LFP (field serviceable).

I am waiting on a quote from their distributor on this “packing kit” before I return them to the eBay seller at his cost.  There is nothing else wrong with them except that they aren’t made to sit around apparently. I haven’t had this problem with Norgren or Parker products but those are for smaller bore applications anyway maybe there is a difference with the O-rings.