Monday, June 30, 2014

June XP-82 Restoration Update




Wings/Center Section
The crew completed the left-hand leading edge and final riveted it to the forward spar of the left-hand wing.


Left-hand Wing

The remainder of the top inboard skins are now completed through their structural high-shear riveting (special collared steel rivets through the wing-attach angles and stringers).  On both wings, the crew has three of the four top skins completed along with the two lower inboard skins at the attach angles. 

We chose to use the center section as the parent fixture for the attachment of the wing-attach angles and the riveting of these upper and lower inboard skins to lock everything in place on sweep and dihedral. The two wings will come off during the second week of July and go into the fixtures for final adjustment and to confirm washout (the downward twist of the outboard section of the wings). 


Lower and Upper Views of the Right-hand Wing


Hydraulic, Instrumentation and Brake Lines
The majority of the lines running along both cockpit floors and up behind and through each firewall are now completed. It has been difficult attempting to duplicate the exact routing of each line as most of them had been removed during the disassembly of the fuselage from the center section in the early l950s.  We were able to get the routing accurate by observing the through-fittings in the center section floor and the line mounts on each longeron. The drawings we have depicted the “B” and later model fuselages, a number of them having the same routing as our XP. 

The overhauled hydraulic firewall-mounted tank has now been completed, including the fuselage suction feed/return and pressure lines. 


Left-hand cockpit prior to final Adel clamping


Completed right-hand cockpit less master cylinders


Hydraulic tank with new hydraulic quick disconnect now mounted to firewall

Seats
We have been restoring the seats and the question came up as to whether we are going to use the original steel armor plate or replace with .437 (7/16”) aluminum plate for weight savings. We have two original steel armor plate panels that can be easily welded, surface ground and repainted.  Where the airplane comes in on weight and balance will make the decision for us.




One of our machine shops completed the two
 XP non-boosted aileron hinge points. 
The left-hand pair show the two separated subcomponents.


The left-hand aileron acme screw trim tab control box and bronze chain sprocket 
are now completed.


Parts Find
The first week of June I received a call from a man in Mint Hill, NC, just south of Charlotte, who had purchased a P-40 project from Ms. Janie Odgers, the family from whom we had bought from the remains of the crashed F-82H out of Fairbanks, AK. Richard Odgers, the now deceased husband, was too ill back in 2008 to travel to Anchorage to complete the sorting of the F-82 parts from the P-40 parts that he had in his warehouse.  Brent VanDervort, whose business is a large hot rod fabrication facility, purchased the P-40 project along with a small cache of F-82 parts.

I made a trip to Charlotte last week to examine what he had and, he had a number of important parts that we were still missing, i.e., four throttle quadrant cable quick disconnects and throttle handle, pilot’s glare shield gun site mount, one leading edge .50 caliber gun barrel fairing and blast tube, and a number of other small pieces of gold.  He declined my offer to pay him and said these parts were supposed to come to us six years ago. 


If anyone is contemplating building a street rod, his company is Fat Man Fabrication, Mint Hill, NC. One cannot believe the quality and the massive amount of different parts that his factory manufactures for the street rod business. Thank you, Brent.


One of the six center section leading edge machine gun ports 
and .50 cal cooling blast tubes.


Pilot's knurled throttle quadrant handle


The last four NAA throttle quadrant cable quick disconnects
that we still needed to complete our cabling.

A Special Visitor
Mr. Jim Sampson, a retired USAF Alaska F-82H pilot from 1946 - 1949, gave us a very nice visit last week. He is the youngest and most agile 93-year-old I have ever met in my life. He could remember flight details, i.e., air speeds, manifold pressures, climb rates, as if it were yesterday. He was very impressed with our restoration and promises to come back on a regular basis.  Thank you, Mr. Sampson, for your USAF service.


Mr. Jim Sampson and Tom

The Katz

Allison selecting a bolt


Allison's Selection of Bolts


"I don't think that the Rockwell hardness on this bolt
 is good enough as I can bite into it." -- Allison



Thankx
Tom

Sunday, June 1, 2014

May XP-82 Twin Mustang Restoration Project Update

Fuselages
The team has been completing the hydraulic and instrumentation lines in the two fuselages. There is a massive amount of these hydraulic and instrumentation lines running through the center section up through the floors and to both instrument panels. Along with this multitude of aluminum tubing, the team has been synchronizing all of the levers on both throttle and propeller quadrants.  The installation of the static lines (neutral air pressure) has now been completed and the lines run to the three locations (two in the left and one in the right fuselage).


Static lines in the left-hand fuselage


Fuel pressure, oil pressure, manifold pressure, airspeed and static lines, along with the parking brake valve in the left-hand fuselage

The hydraulic lines under the pilot’s floorboards that run among the coolant tubes has been somewhat of an issue reinstalling them exactly the way the prototype had them.  In the production airplanes, they were routed in a much more logical order, not that our duplicating the original has caused any problems that we were not able to over come.


Floor hydraulic lines prior to Adel clamp mounting

The team also completed all of the flap hydraulic lines that run out the trailing edge of the center section and attach to the flap hydraulic cylinders that are mounted on top of the center section underneath both fuselages.  The flap lines run from the flap hydraulic selector that is mounted aft of the left-hand center section wheel well to the center of the gun bay, then aft to the rear of the center spar.  They then split and two lines on each side run out to the retract cylinders that are mounted on the underside of both left and right fuselages.  

NAA had a unique way of installing flexing lines on both the two main retract cylinders and the two flap cylinders.  Instead of having a swivel joint, they just bent the hydraulic line(s) in a 360 or 720 degree flex circle, depending on the amount of flex that each cylinder would exert on the line.


Flap cylinder (upper) and aft spar hydraulic lines (below)



There have been comments on our website and/or Facebook as to why we are using AN fittings.  On our XP-82 and all subsequent production versions of the F-82s, North American used all AN fittings which replaced the Curtiss (A/C) fittings that were used on all previous North American products.  


Curtiss on the left; AN on the right

On our aircraft, the prototype, North American had put in four static port holes in the fuselages to find the zero pressure area for the static ports. We have duplicated these test static holes for originality.



Canopies and Windshields
Both canopies are now totally finished and all of the canopy trucks are completed and ready to be installed.  The two glare shields (pilot and, co-pilot) and armor center windshield panels are now completed awaiting the forming of the side glasses. 




New machined canopy truck

Wings
There has been just about a full team effort to complete our two wings. The team has completed the riveting of the leading edge as a subassembly and all of the aluminum lines are now installed.  These consist of electrical conduit tubes, aileron cable guidance tubes, pitot lines, drop tank pressure and return fuel feed tubes, boost pump, liquidometer, strobe, tip lights and pitot heat conduit tubes.  The bottom inboard skins on the right hand wing are now completed awaiting the closeout panels.

Every top and bottom skin on the left-hand wing is now completed with all of the dimpling, counter-sinking and edge fitting.  Also being completed is the left-hand leading edge and the four  top  wing skins for the left-hand wing which are being riveted this week.


Newly formed left-hand leading edge bow


Right-hand wing


Aluminum tubes and wiring in the left-hand wing leading edge


Subcontract Machine Shop
All of the aileron and flap hinges are well on their way to being completed, and the aileron sectors are also in process. The last large machine shop items to complete will be the four secondary engine mount structures. These large pieces are shaped like a T platform and bolt to the Merlin engine mount pads. These are not complicated pieces to make.

Firewall
The large exopy-cast tooling mold that we made a couple of months ago is now completed with its ½” steel welded containment structure to support the bottom and sides. When we press the stainless steel into the mold, we’ll apply over 200 tons of pressure.  With the ½” steel structure surrounding the epoxy mold, the press will not shatter the epoxy.


The Katz
After a relaxing two weeks at the beach, the Katz are back and trying to find a cool spot to hang out.




Thankx
Tom



Wednesday, April 30, 2014

April XP-82 Twin Mustang Restoration Update



 April was a great month with lots of good progress.

Wings/Sheet Metal
The men have been making excellent progress on both wings. The majority of the skinning and riveting on the forward top and bottom of the right-hand wing is now completed. All of the in-conduit wiring, pitot, and aileron cable tubing, and drop tank pressure and feed lines are now pre-installed in the right-hand wing. 

The final structure set-up on the left-hand wing has now been completed and the preliminary dimpling, counter-sinking and skinning of the top skins is progressing.

Due to the spring/summer temperature changes, the crew must check the washout, sweep and dihedral each morning when it is cool and each afternoon as the temperature increases 30 to 40 degrees. The wings are fixtured to not allow the temperature variations (expansions and contractions) to change the set-ups.  We must maintain the exact dihedral and the washout measurements to within one-twentieth of one degree so that the aircraft will fly “hands off”. 

With the dihedral and washout locked in to those degree settings, the final reaming of the .3735 lower wing-attach bolt holes on both wings has now been completed.  (A reamer is a precision cutting tool to bring a reduced-drilled-size hole out to final size. A drill bit will not drill a precision hole.)

On wing-attach angles, nut plate channels are used where one cannot gain access to the wing-attaching nuts to tighten them. North American, however, installed nut plate channels with nonstandard spacing on the upper sides of the lower attach angles located in the fuel tank bays. None of the original channels we had were repairable, and the uneven spacing made it impossible to purchase a standard nut plate channel from any supplier.  Thus we had to make up all the new nut plate channel strips.


Wing attach nut plate channels


Left-hand lower wing attach angle with nut plate channels riveted on.

One of our sub-contract machine shops is now heavy into completing the aileron sectors and mounting hinge points for both wings.


Canopy, Windshields and Glare Shields
The second canopy glass has now been fit into the repaired canopy frame. It took parts out of all three damaged canopies that we had to repair and complete the right-hand canopy frame

The damaged and corroded right-hand canopy frame


Repaired right-hand canopy frame with fitted glass

The right-hand glare shield was another story.  The restoration to the left-hand one was relatively simple as it was basically undamaged.  The damaged right-hand one required a major amount of repair and splicing together many repressed parts to complete an airworthy unit. 


Munched right-hand glare shield


Newly repaired right-hand glare shield

We have completed both center 1.5” thick, bullet-resistant windshield glasses.  We are in the process of forming our four windshield side glasses to fit the windshield bows and glare shield frames. 


 New 1.5" thick, bulled-resistent windshield glasses

Throttle Quadrant Cables
One of our men is currently completing all of the cable hook-ups that simultaneously link both quadrants together through cables that run through the center section from one cockpit to the other. 


The original throttle quadrant


Throttle quadrant cable hook-ups with detail (below)



Inside Skins for Outboard Gear Doors
Pat Harker (F-82E, Anoka, MN) has built the tooling and has successfully pressed one set of skins for his serpentine-shaped outboard gear doors. He has offered to sell us a pair for our project.  Thank you, Pat!



Heat Treating
We brought another batch of parts that needed heat-treating to Thrush Aircraft in Albany, GA, to be brought up to T-3 condition. The amount of special help Thrush has given us has been priceless. Thank you, Thrush.


Thrush Aircraft's new 710P
"Unmatched power.  Unquestioning control"

The Katz
They took two weeks off to go to Daytona for Spring Break.  More on the Katz next month.

Thankx.
Tom