Wednesday, May 4, 2016

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




Monday, April 4, 2016

March XP-82 Twin Mustang


 Firewall Forwards (FWFs)
All of the upper cowling hat channel ribs have been completed and final fit. Three team members have been reworking the original firewall forward left-hand engine LH and RH top/side panels that go from the firewall to the propeller, one on each side, that came with the original purchase of XP-82. They had been out in the weather for years with countless pieces of steel and aluminum stacked on them, introducing numerous dents and scratches.  The team members have been English wheeling these dents out of the surfaces and burnishing out the scratches.


Original top engine cowl (right-hand)

We received back two full sets of new 4130 steel cowling latches. We had to order two complete sets, one for each engine, as all of the original steel parts were rusted beyond repair. These parts had to be sent for heat-treating to be brought up to the proper hardness and then on to cadmium plating. 


Cowl latches

The two NOS generator cores were just received back in overhauled condition from Aero Accessories in San Antonio, TX. Each one will have been installed on each engine by the time you read this.

All of the 28-volt FWF wiring harnesses, fuel/oil/manifold pressure/vapor return and vacuum lines are totally completed on both engines.


We also had to have two special  30° offset #16 (1”) carburetor inlet fuel fittings machined. These two fuel fittings adapt the upgraded Aeroquip 302A-16 fire-resistant hoses running from the engine-driven fuel pumps back to the carburetors.


Wing Center Section Leading Edge
A lot of work has been going into the leading edge stainless steel gun ports (six). We had two out of the Alaska wreck site that were basically undamaged. We also had two that were partially damaged and able to be salvaged, with two having to be formed and welded from scratch. This is a complicated procedure as they must precisely fit the new-formed leading edge.


Leading edge gun ports just starting to be fit

Tail Wheel Assemblies
We are about 90% finished with the two tail wheel assemblies with about another 90% to go. These are extremely complicated mechanisms that have at least a thousand moving parts. We have about 20 parts left that have to be machined and still must go to heat treat and/or cadmium plating.

The new tires and tail wheel tubes have been mounted on the two tail wheel assemblies awaiting final mounting when the axles return from cadmium plating.

We are having the tail wheel door skins (four) pressed as we speak.


.50 Caliber Machine Guns
The final fitting of the six .50 caliber replica machine guns is advancing along well. We were able to purchase all of the ammunition we need from a machine gun dealer friend. We have even gone as far as finding original 1943 date code armor-piercing, empty powder ammunition with live primers and black tip (armor-piercing designation) bullets. What we must do for authenticity is polish off the black tip on four out of five original projectiles and dip the tip of one of every five linked cartridges into an orange-red paint to designate a tracer round. This way, out of five linked cartridges, #1 will be armor-piercing, #2 will be a tracer, and #3, #4 and #5 will be standard ball ammunition.      

         
We have also gone to the extent of installing original .50 caliber barrels and cooling jackets so that when one looks into the leading edge of the wing center section, they will be able to see the rifling in the barrels.

The armament specialist that we have hired is progressing nicely on fitting the feed chutes and link ejector discharge chutes. All six guns have been temporarily installed for final fitting.



Six .50 caliber machine guns mounted looking aft.
One can see the gun heater and firing wires
coiled up prior to routing and hook-up.


The Kat
Allison just returned from Spring Break.


Thankx
Tom

Wednesday, March 2, 2016

February XP-82 Twin Mustang Restoration Newsletter & Photography

Firewalls Forward (FWF)
We are progressing very well with the multitude of FWF tasks. The remaining FWF tasks to complete are as follows: both oil feed lines (one from each oil tank), one glycol coolant return line to each firewall, one oil return line from each engine to heat exchangers and generators.

Engine Cowlings
Each engine has three lower Dzus cowls. Both lower forward cowls are now complete and both second-from-the-forward cowls are nearing completion. All of these cowls have compound shapes requiring English-wheel forming. 


English wheel used for forming compound bends


Completed lower forward cowling

All of the ram air cooling blast tubes are now formed and awaiting installation.




Both engine-driven fuel pumps and left engine hydraulic pump tubing and hoses are completed (the XP-82 has only one hydraulic pump fitted).  Not an issue as the landing gear will free-fall and positive lock down.

Fuel Systems

All six fuel tanks, 600 gallons total, are now completely installed including boost pumps, fuel shut-offs, check valves, cross-flow valves, scuppers, etc., and are awaiting filling with AV gas to test each for leaks. With 600 gallons of internal fuel, the XP-82 (Merlin-powered) burns 100 gallons per hour at 300 mph cruise speed, giving it an 1800-mile range. With four 300-gallon drop tanks added, 5000 miles maximum. 


Firewall Aft Coolant System

Every coolant line from both radiators and spherical header tanks running forward to each firewall is now totally installed. A substantial job, the same as doing two complete P-51 cooling systems.



Electrical Systems
We are about a month away from completing the last few outstanding items on the electrical system. At that time we will put power on the ship for the first time to check out each system. A huge “thank you” goes out to Concorde Battery Corporation for contributing their best maintenance-free 24-volt battery. (I had one in my B-25 Mitchell and it lasted only nine years! Unbelievable!)

Inboard Gear Doors
Both inboard gear door frames are now with one of our subcontract machine shops being fitted to the large aluminum press dies to press the complicated inboard door skins.


Also, another huge “thank you” to Thrush Aircraft,  manufacturer of the best agricultural spray aircraft, for the heat-treat processing of hundreds of cowling and gear door parts for us.

Guns/Barrels/Cooling Jackets
We purchased the six cooling jackets that thread into the forward part of each .50 caliber receiver. The six original .50 caliber barrels that we have also screw into a separate set of threads in the receivers.


Fourth from left shows .50 caliber barrel inside the cooling jacket

Tail Wheel Assemblies
These tail wheel assemblies must have been designed by Rube Goldberg. They have an amazing amount of moving parts just to retract, steer and lock. Even though the majority of the parts were not damaged due to the Alaska impact crash from where we recovered the parts, most were non-airworthy due to being under water for sixty years. I am making a good headway and plan on having both installed, one in each aft fuselage, within a couple of months.



Partially assembled retractable, steerable and locking tail wheel unit prior to finish coats of Imron paint. 
Only about half of the parts for one unit are showing in this picture.


Monday, February 1, 2016

January XP-82 Twin Mustang Restoration Project Update


2016 is going to be a banner year
for our XP-82

Fuel Systems
The major job this past month has been installing the wing and center section fuel tanks, boost pumps, liquidometers and sump drains.  The installation of the two center section 95-gallon tanks was completed around the first week in January. Three of the four outboard tanks are now installed less their pumps and liquidometers. All of these will be completed when the fourth tank is finished around the first week of February.



Left-hand and right-hand installed boost pumps less safety wire


Inboard Gear Doors
The job that I had been planning for years was to manufacture the two exceptionally complex-formed inboard gear doors. We recovered two extremely damaged inboard doors from the Alaska wreck site. Neither one had any usable parts, but parts of both gave us highly valuable information. Between these two crashed door remains and the very detailed NAA plans that we have, two team members were able to complete both door frames in a short amount of time. The pattern of the press die for the inside skins is being designed.


One of our machine shops supplied us with our four needed gear door hinge points. 


Upper & Lower Engine Cowlings
Our machine shop finished all of the 4130-steel left-hand and right-hand upper cowling adjustable-Dzus-rail-attach points. These are the attachment fittings that join the two top cowls together down the centerline of the top of each Merlin engine. 


With the lower cowling ribs being finished over the past month, the English wheeling of the six (three each engine) lower cowls has been started. Within a short amount to time, the team had the first forward lower wheeled cowl completed. The wheeling of the five remaining cowls should go smoothly. The two filtered-air screen ducts still need to be fitted in the sides of each forward cowl.

It would have been nice if these cowls were the same as a “D” model Mustang so that they could have been purchased from the current P-51 parts builders, but no such luck.




Armament / Replica Machine Guns
We received our six machine guns from the machine shop. The duplication and detail of all the parts copied from a non-fireable real .50 caliber gun are superb. All we had to do was paint and assemble each gun, and now all six are being installed in the center section gun bays.

I was also able to locate through a machine gun dealer/friend of mine, enough original WWII  .50 caliber fired shell casings with the correct date code “44” stamped on the back of each shell for authenticity. 






Rollout Time Frame
We are planning for the first roll out of our XP-82 to see the light of day sometime early this summer. The main task that has to be accomplished prior to that rollout is the completion and installation of the tail wheel retract mechanisms/tail wheel assemblies. 

At that time we will have Nixon’s Vintage V12s (company that overhauled our two engines) come from California to start both engines and final test all firewall forward systems (fuel, oil, vacuum, hydraulic, propeller, etc., etc.).

Final Major Tasks to Complete
The five major tasks to complete are as follows:  the pressing of the one FWF dishpan and the two inboard gear door waffle skins, fitting the two outboard gear doors, and machining and installing the two brake calipers. The last item is the pressing and assembly of the air induction trunk forward lip/carburetor air control mechanism (two) located under the prop spinners.

The Kat
Do you want the length or the width?”
-Allison


Thanks!
Tom