Wednesday, January 4, 2017

December XP-82 Twin Mustang Restoration Update

Merry Christmas & Happy New Year!  
Another month has gone by so fast.

Much time has been spent on the final fitting of the rotating carburetor air temperature mechanisms, along with the air intake lips and the four side panels.

Carburetor air control housing assembly and rotating internal barrel

Lower carburetor air intake chin cowl

As mentioned last month, all of the lower and side engine cowling panels are now completed. The final shrinking/stretching, English wheeling and Yoder hammer forming of the top two right-hand engine cowlings will be completed in the month of January. The left-hand top panel for the right-hand engine is now final formed and fit. The right-hand top panel still needs a little more stretching and wheeling. 

The six oxygen bottles are now fit in each fuselage along with all of the fill feed tubing and one-way check valves. The fitting of the two O2 Blinker gauges, along with the Oxygen Diluters is being accomplished. Below this O2 Diluter shelf is where we are planning to hide the complex Garmin avionics package to maintain originality.

Trying to find the original routing of the O2 tubing was a challenge as all of the plans that we have show extremely stylized drawings which contradict similar drawings on the following pages. We were able to locate the original drilled holes in some of the rejected side ribs, allowing us to be able to determine the location of the original line clamps. They were in dramatically different locations than the stylized drawings. We also were able to find the NOS four-way Schrader check valves to install to maintain the authenticity of the O2 systems.

Tight working around the coolant header tank

Large O2 bottle mounted in the lower rear of each fuselage

Two small O2 bottles are mounted in the top forward of each rear fuselage

The mounting of the gun sight in the left-hand cockpit and the gun strike camera in the right-hand cockpit is proceeding, I hate to say, slowly. Trying to put everything back into this XP-82 identically as it was on day of its first flight, 15 April 45, is excruciatingly time consuming. 

Gun strike camera being fit on the right-hand glare shield

Gear Doors
The preliminary forming dies for the main gear center section doors are now complete. The internal pressed skin for each door is a mirror image of the other side. Many hours of machine shop computer work went into these press die patterns.  These two center section gear doors are two of the last four major items to complete on our XP-82 restoration.

Control Surfaces
The final balancing of all the control surfaces, i.e., four ailerons, two rudders and one elevator, is now complete. (Aircraft control surfaces must be precisely balanced [in accordance with the XP-82 Erection & Maintenance Manual] equal weight forward and aft of the centerline of the hinge points.) If they are not balanced, they will flutter in flight as a flag does in a heavy wind on a flagpole. We had to add some additional leading edge weights to each surface because we replaced all of the hinges, trim tab fittings and trailing edge strips with a much stronger and heavier weight 7075 T6 aluminum in place of the original lighter weight cast magnesium fittings and strips. Trim tab fitting failures during high speed flight have been known to be fatal.

Counter weights installed on the leading edge of the ailerons

Wing Tips
Three of the four wing tip formed skins are now completed with the fourth being completed this week. When completed, each half will be TIG welded (tungsten inert gas) by our professional welder in Florida. He will match exactly the TIG welding bead pattern done on the original wing tips. 

The Kat
“You say you are going to get me another kat to keep me company. I will start to do interviews this Tuesday.”


1 comment:

  1. Those wing tip skins are almost as remarkable as the project itself, which is 11 on a scale of 1-10! Thanks for the monthly updates once again, have not missed one in years!