May XP-82 Twin Mustang Restoration Project Update

Firewall Forwards (FWF)

The team has been busy final English-wheeling the three lower cowls on each engine. They also completed the four filter door access panels located in the forward left and right section of each lower forward cowling. 

The two original top cowls for the left-hand engine were in pretty tough shape. But, with countless hours of addressing a multitude of small dings, scratches and the occasion hole and, many hours of English-wheel time, they came out virtually perfect.

The team is wheeling from scratch the two right-hand top cowl skins (each 3 feet x almost 8 feet long). 

They also completed the two right-hand lower side engine cowlings, the ones that surround the forward, lower and aft edge of the exhaust stack opening. These both had to be English-wheeled where they curved in and around to match the circumference of the prop spinner. All of the internal ribbing and structure had been completed for the right-hand engine cowling a number of months ago. When the last of the wheeling of the two right-hand top cowls is completed, all of these components will be spot-welded together.

The welding of the 4130 steel FWF throttle and propeller governor control rods is now completed and awaiting installation. 

Fitting the side cowls to the temporary wooden form on the right-hand engine

Carb Air Temperature Controllers

The last two complicated jobs to complete on the FWF is the fitting and mounting of each carb air temperature control mechanism and rebuilding the forward air induction intake scoops. We have one that was extremely damaged due to years of rough ground handing. It has now been pressed out to approximately its original shape good enough to tell what it looked like and to get some data measurements from the reformed piece.  We will have to make two new ones as the original is too damaged to save. With the XP-82 plans that we have and the original semi-straightened intake, two new ones can be made.

Reformed damaged carburetor air induction scoop

Ammunition Feed Chutes and Motors

Out of the wreck site we recovered a partial set of ammo feed chutes with the mounted Hughes (as in Howard Hughes), electric .50 caliber feed motors. They were all extremely damaged by the impact. We had no luck being able to buy any of these from any of known armament sources. So, we were committed to try to save what we had. 

Original damaged ammo chute

Hughes Aircraft Company Ammunition Feed Motors (NOS)

Assembling the ammo chute pieces prior to welding

Right-hand Firewall Stainless Dishpan

The pressing and forming of the right-hand dishpan has been a challenge. It somewhat resembles a rectangular kitchen sink.  When this dishpan is completed and installed, both oil tanks and heat exchangers (oil coolers) can be mounted and attached to their respective oil and coolant tubes. 

Leading edge with the six .50 caliber gun ports 

being installed on the center section

Fuselage Closeout Access Panels

One team member has completed the final detail fitting of every access panel on both fuselages and center section. These flush panels had to be precisely edge-fit as they are flush-mounted with the fuselage skins. A lot of detail edge sanding to maintain a .030 edge dimension, with a number of panels going into the scrap aluminum bin when the edge distance exceeded that dimension.

Tail Wheel Assemblies (as mentioned last month – 90% done with another 90% to go)

We had to manufacture two new down-lock barrel stops as, over the years, the tail wheel stop mechanisms striking the barrels had elongated the .750 barrels and the hat channel structure they mounted into.  The fix was to buy a special .770 reamer and ream out each barrel hole so that the new .770 OD barrels fit tightly in the precision-reamed structure.

Both steering arms that attach to the top of each yoke are now installed, waiting for the machining of the two rudder control arms that are connected to the lower steering sectors mounted in each rear fuselage. When these two arms and one remaining sector are completed, they can be mounted and the final cables installed to complete the tail wheel steering. 

With these tail wheel assemblies finally completed, 

and the tail wheel tires and wheels mounted, 

our XP-82 will be able to roll on its own wheels for the first time in 66 years.

The Kat

"See that Tom gets me a larger table to sleep on during work hours before I fall off."

-- Allison

"We need to talk to the Union steward about your sleeping during work hours."

-- Tom

Thanks!
Tom

April XP-82 Twin Mustang Restoration Project Update

We finally see the light at the end of the tunnel and it’s not an oncoming train!

Center Section

The very difficult job of repairing and remanufacturing the leading edge gun ports is now completed. Most of these gun ports were severely damaged due to crashes and years of being pushed around by heavy equipment while in an Alaska scrap yard. 

After a massive amount of rebending and straightening we were able to reweld the straightened cracked areas with the exact alloy stainless rods so that the weld matched the original alloy of each gun port, and the repaired areas are not visible. We could have easily manufactured all of these gun ports new, but I chose to attempt to keep as many of the original parts as possible.

Original reworked stainless gun ports

Armament

All six replica aluminum .50 caliber machine guns are now mounted and aligned perfectly. We are installing original barrels and cooling jackets for authenticity so that when one looks into the barrel the rifling will be visible.

We had four volunteers work all 2400 rounds of .50 caliber ammunition. Each ammo tray holds 400 rounds for each gun. We decided to completely fill each tray (box) for authenticity with all the correct tip color-coded ammunition. We spoke to an original WWII armorer that loaded P/F82s in combat service and he advised us on the color pattern of the linked ammunitions. #1 Red Tip – Tracer, #2 Silver Tip – Armour-piercing Incendiary, #3 – Black Tip – Armour-piercing. #4 – Silver and #5 – Black. This order repeated for all 400 rounds in each of the six gun ammo trays. A very time consuming job, but now done. Thank you!

We even found hundreds of rounds of original inert date coded Milwaukee M-43 (1943) ammunition that we tip-painted and are installing for authenticity.

 Loading the .50 caliber cartridges into the linker

Pressing the linker

Linked .50 caliber cartridges and ammo box

Original .50 caliber cartridges - M  4  3    (1943)

Lower Cowling

The team members are heavy into the last of the six engine cowls. These last two close out the bottom up to each firewall against the main gear doors. There is also structure that the center section leading edge and the fuselage-to-outboard-wing fairings attach to that had to be repaired and/or made new.

The four filtered-air-intake-formed panels have also been fit in each side of the forward lower cowlings.

Forward cowling and carburetor filtered air intake

 with temporary Dzus fasteners (1 of 4)

Engine/Carburetor Induction Trunks

These are two parts that are virtually identical to the P-51 Mustang. We purchased these induction trunks from Aero Trader in Chino, GA. They are magnificent pieces of workmanship that they made. The only change that needed to be done was to change the carb-air-temperature-door-actuating-rod lever from the left-hand side (P-51) to the right-hand side for the XP-82.

One of our subcontract machine shops completed the air diverter that mounts just under the prop spinner. This diverter controls the air temperature that passes through the induction trunk into the carburetor. The four positions are: Cold Ram Air, Hot Air (for carb icing), Half Hot Air and Filtered Air. Manufacturing this air diverter was an extremely difficult job, but it came out superb. Thank you!

Coolant Tubes

The two venturi coolant tubes that control the Glycol flow (coolant) out of the supercharger intercooler(s) back to the heat exchanger(s) are now both completed and awaiting installation.

 Tail Wheel Assemblies

Both tail wheel assemblies and all of the retraction “A” frame mechanisms are now permanently installed. We are waiting for the last dozen or so steering mechanism parts from the machine shop to complete the steering hookups.

Right-hand tail wheel retract arch

Tail wheel lock and steering plate

Tail wheel up and down position bungee locks

Part of the tail wheel assembly

Completion

The last major components to finish are the two inboard gear doors, the two brake calipers, a complete set of fuselage-to-wing and tail fairings; and countless other small jobs that are on the “to be completed” list.

The Kat

“These bullets aren’t loaded, are they? You know I don’t like loud noises!”

-- Allison

Thankx
Tom

Quote of the Month

“A man who is good enough to shed his blood for his country is good enough to be given a square deal afterwards.”

 --Theodore Roosevelt