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( 2.9 / 200 )With a little gentle application of a heat gun to soften the glue along with a sharp razor, I had the starboard skin of the rudder removed in about a half hour. As I suspected, the interior of the rudder had not been varnished. Strictly speaking, that enclosed area doesn't require varnish. However, varnishing the interior does help with dimensional stability of the plywood skin as humidity changes, thereby preventing oilcanning and warping.
I am now able to access the trim actuator. It is a simple powered lead nut salvaged from something. The linkage to the trim horn consists of a leadscrew on one end that threads into the actuator. My problem with this setup is that there is no limit to the motion. In a trim runaway situation, the actuator would keep going until something broke - I'm fairly certain the motor has sufficient torque. This will be replaced with a standard MAC servo or equivalent.
I removed the light and associated wiring. I plan to use an LED tail light, but I haven't decided which one to use yet.
I also removed the sharp leading edge piece. Once the new skins are in place, the plan-specified rounded leading edge will be shaped. The rest of the workmanship appears above average.
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( 3.1 / 105 )The first part of the purchased airframe I decided to check out was the rudder. Falconar supplied plans for several different rudder versions over the years. This is the full-flying rudder that is slightly swept.
I am checking this part against Falconar drawing 119A 83 Iss. 5, sheets 1 and 2. Status of the components by callout number are as follows:
-1 - 1/4"x1/2" strips and 1/16" birch ply OK
-2 - 1/4"x1/2" strips and 1/16" birch ply OK
-3 - 1/4"x1/2" strips and 1/16" birch ply OK
-4 - 1/4"x1/2" strips and 1/16" birch ply OK
-5 - 1/4"x1/2" strips and 1/16" birch ply OK
-6 - 1/4"x1/2" strips and 1/16" birch ply OK
-7 - Obscured
-8 - Partly obscured, 1/16" ply OK
-9 - 1/16" ply, ash blocks, ply doublers, and 1/8"x5/16" strips OK
-10 - Upper nose ribs made from 3/8" pine block instead of 1/4" ply. This part is not subject to significant loads, OK
-11 - Starboard skin is delaminated from the ribs in numerous places. Skin extends further than necessary. Remove and replace skin and trim to plans shape.
-12 - 1/16" ply OK, though face grain isn't oriented as shown in plan
-13 - 1/16" ply OK
-14 - Cover not present. Will be made after rudder is fit to fuselage
-15 - Trim tab not to plans. A larger tab has been made that is hinged to allow for electric trim. A servo and linkage are present as well. Although the tab is OK, the linkage is unacceptable and the servo is suspect. The linkage contains a double link to "turn the corner", but is insufficiently constrained, so the flexibility of the pushrod allows uncommanded movement of the tab with only slight sideways pressure. A longer horn on the tab will solve the linkage geometry issues, but the servo will still need to be checked out.
-16 - Skin in radius area OK
-17 - Hinge plates not present
-18 - Eye bolt is homemade, not specified AN hardware. Finish is poor, with cut threads, no cad-plate. Replace with appropriate AN hardware.
-19 - Nut is not appropriate AN hardware. Replace.
-20 - Washers not present or not appropriate AN hardware. Replace.
-21 - Clevis pin not present
-22 - Washer not present
-23 - Cotter pin not present
-24 - Rudder control horn has poor finish with rough edges, insufficient hole-edge clearances, and sharp internal radii that are prone to cracking. Not attached with AN hardware. Make new part and attach with appropriate AN hardware.
Other issues not related to a part callout:
* The leading edge of the rudder has a rather sharp radius made by the addition of an additional wood strip. This will be removed and the leading edge reshaped to plans. In addition to adding unnecessary weight, this could change stall characteristics of the rudder.
* The light attached to the top of the rudder is not the correct nav light. Also, the wiring is not teflon. Replace the light and wiring.
When removing and replacing the rudder skin, I will have a chance to better view the internal components and give the inside a good coat of epoxy varnish.
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