Saturday, February 3, 2018

January XP-82 Twin Mustang Restoration Update

Happy New Year Everyone
2017 was a great year for our XP-82

Firewall Forwards
Two team members were able to successfully press both exhaust fairings, trim to fit and punch out the twelve exhaust port openings. With a small amount of final hand forming, they had them fit, drilled and attached to both right-hand engine cowlings. They were able to use our 200-ton rubber press machine to initially press the .050-thick stainless steel and finish detail using the newly machined 300 lb. male and female press dies. 

Carburetor Air Temperature Hot Air Door Controls
Mounted in the back of each induction trunk is a door that opens to control the pilot-selected amount of carburetor heat (anti-icing) into each carburetor. These doors are controlled electrically by either pilot from “closed,” to “half hot” to “full hot,” depending on the outside air temperature and humidity during each flight.

The hookup from the electric motor that rotates the air intake barrel back to the slide mechanisms, then down through two 90-degree arms, to a cable, then through a 90-degree pulley and back to the door arm was a difficult geometry puzzle to make them work on each induction trunk. 

Inboard Gear Doors
Both inboard gear doors are now completely finished, interior painted, trimmed, new hinges attached and both fit to the center section. Both doors have been hydraulically retracted, snapped into the hydraulically controlled up-lock latches and successfully released and extended numerous times. 

Tail Gear Doors
All four tail gear doors are now completely finished, interior painted, eight hinges and four retract rods attached and final fit into each tail wheel position (two). We are awaiting two small brackets that mount on the two tail wheel lower arms that the pull/push rods attach to for retraction and extension. (The hangar lights make the paint colors appear different.)

Aileron Bellcranks
We installed the aileron bellcrank boxes, one in each wing. These two boxes have a large cable sector with a lever arm that attaches to a push rod coming from the bottom of each stick. The movement of each synchronized stick (left or right) rotates the cable sector that has two cables attached to it that go out through the wing through two 90-degree pulleys 
and then back to another sector and arm that is attached to the ailerons.

Wing root sector box (above and below)

Aileron sector box

Push rod from stick to wing root sector box

Wings/Center Section Fuel Tank Testing
The center section has two 95-gallon fuel tanks, one located underneath each cockpit floor outboard of each gun bay. Each outboard wing holds 205 gallons of fuel and has provisions for two drop-tanks holding a total of 450 gallons under each wing. Each drop tank has the ability to be air-pressurized from the vacuum pump discharge air through a cockpit selector to air force the fuel back to the inboard center section 95-gallon tank. Total internal fuel capacity is 600 US gallons. 

In December all six tanks were completely filled with fuel to test for leaks. 

Cross-flow Check Valves
There are two cross-flow check valves, one mounted above the belly scoop under each fuselage. These check valves control the fuel flow from the fuel tank boost pump located in each outboard wing and the fuel flow from the inboard 95-gallon tank boost pump to each engine. These valves prevent the outboard fuel being transferred to the inboard tank and vice versa.  Boost pump fuel coming from either tank(s) through the check valve housing will only go forward to the engine.

Fuel Shut-off/Cross-feed Valves
These electronic shut-off and cross-feed valves have been final tested and associated hoses attached. These valves are Whittaker guillotine-style valves that have a chrome-plated sliding plate that electrically/mechanically opens and closes off each port.

Fuel valve is shown partially closed

The two flap hydraulic cylinders have now been attached to the flap arms and hydraulically actuated, and the flap up-and-down stops have been adjusted.

Flap Follow Up Mechanism
This mechanism is mounted on the left-hand cockpit floor underneath the flap actuator handle. It is a mechanism that synchronizes the movement of the flap handle, the flap hydraulic actuator and the position of the three flap panels. 

Aileron Trim
The aileron trim bellcrank and chain/cable mechanism has been completed, installed and tested.

Tail Wheel Unlocks
We were able to manufacture the two missing tail wheel steering unlocks. These unlocks release the tail wheel steering when either stick is pushed all the way forward. They are actuated by the down-elevator cable, one in each rear fuselage.

Leading Edge with Six .50 Caliber Gun Ports
The center section leading edge has been left off in order for us to make the final adjustments on the gear door up-lock mechanisms. Now that these adjustments have been made, we have been final fitting the leading edge and its installation will be completed by the end of next week.

The Kat
“With me siting here, be careful where you cut with that large pair of shears that you have in your hand!”

— Allison


Thursday, November 2, 2017

October XP-82 Twin Mustang Restoration Update

A very nice drawing of our warbird by Mark A. Ehlers

Hoses and wiring behind the co-pilot's instrument panel

Hoses and wiring behind the pilot's instrument panel

Left-hand inboard main gear door without external skin being final fit

Left-hand inboard gear door with latching being final fit

Left-hand inboard gear door showing unlock latches, hooks and
the internal rib structure

Pilot's instrument panel installed
The loose wires are avionics (radio) wires still
to be hooked up

Co-pilot's instrument panel installed.
Note the gun strike camera mounted.

Left-hand wing tip with position light installed

Right-hand wing tip with the position and recognition lights installed

Engine Run
We pulled our XP-82 out on to the ramp, tied down both tails and chocked both main wheels and started both engines simultaneously for the first time.  We initially ran them  at an idle for about two minutes until I had the oil and coolant temperatures come up, and then I brought them both up to a little over 1000 rpm (not fast enough to check generator or propeller functions). 

All of the fuel, oil, tachometer and associated temperature gauges worked as expected.

Both engines running 14 October 2017

Gear Doors - Two Main & Four Tail
A job that I thought would be very difficult, pressing the two inside waffle skins, turned out to be a very quick and efficient job that came out perfectly within three weeks. Two team members completed all of the interior framework including the installation of the up-lock latch forgings (two per door) along with the two flat exterior skins. 

I took the two main gear doors along with the four tail wheel doors to Kermit Weeks’ in Polk City, FL, to be spot welded. With these six doors completed, that completes 99.9% of the sheet metal work on our XP-82. The only remaining sheet metal items are the two outboard gear doors and the adjoining lower engine close-out fairings that we cannot complete until we have the exact curvature and pattern off each outboard door.  We are waiting for these two outboard doors to be delivered.

Pat Harker supplied us four tail gear door interior pressings. Within a few days these two team members had them fit to our eight installed hinges with the newly formed outside skins. These outside skins are now spot welded to the inside pressings.

Main inboard gear doors. Interiors were alodined prior to primer painting.

Tail wheel gear doors

Forming the stainless steel liners for the interior of the main gear doors

Newly machined press dies (male and female) for the exhaust fairings for the right-hand engine. We will use a 200 ton press to press these .050 stainless steel fairings.

Carburetor Air Induction System
The final installation of the rotating barrels, located underneath each spinner that control the air induction temperatures, and all of the induction trunks back to the carburetor inlets are now completed. The only thing to complete on these induction systems are the rod and lever mechanism adjustments that open the hot air doors for carburetor heat.

"Does this picture make my butt look fat?"   ---- Allison


"I don't lose any sleep at night over the potential for failure. 
I cannot even spell the word.”
Gen. James “Mad Dog” Mattis


Saturday, September 2, 2017

August XP-82 Twin Mustang Restoration Updat

Fourteen forward firing .050 caliber M3 machine guns
Pictured, our prototype XP-82, with the experimental eight-gun. 050 caliber pod attached to the underside of the center section, test firing along with the six center section .050 calibers. Notice the pile of brass underneath the center section.  (Circa late 1940s)

Fuselage Fairings - Inboards and Outboards
All of the fairings are all now completely finished. The last task on all twelve fairings was polishing out the microscopic English wheel roller marks. They are all now mounting-hole drilled. All of the edges have been trimmed to match and all are now completely fit and installed. 

Above:  Left-hand outboard trailing edge fairing
Below:  Left-hand outboard leading edge fairing

Above:  Left-hand inboard leading edge fairing
Below:  Right-hand inboard leading edge fairing

Above:  Right-hand inboard trailing edge fairing

Above:  Right-hand outboard leading edge fairing

Above:  Right-hand outboard trailing edge fairing

Top Engine Cowls
Both top cowls (right-hand engine, left and right) are completely riveted, spot-welded together and now undergoing final polishing and edge trimming. They have been a chore, but have finished out very well.

Spot Welding
Both right-hand newly manufactured engine top cowlings were brought to Kermit Weeks’ facility in Polk City, FL, for spot welding. Rick Reeves, the man that helped form many of our parts, did the spot welding for us using Kermit’s state-of-the-art spot welding machine.

Every electrical system in our XP-82, with the exception of the landing gear position wires, has been system-power checked out. The massive number of wire harnesses in each cockpit is now being tie-cord wrapped (aviation cord instead of tie wraps).

The Instrument Panel Covers
The aluminum closeout panels over the top of each instrument panel have now been completed.

Hydraulics/Landing Gear
We had some timing issues with both the landing gear and flap actuating valves, but they have been adjusted and hydraulically tested in the test bench where they have checked out perfectly. They will be installed this week in order to start the gear retractions.

Tail Gear Doors
We received the four tail gear door inner pressings from Pat Harker (F-82E, Anoka, MN). He had male and female press dies machined to press his inner tail wheel waffle skins. So, instead of our having to duplicate these dies to press a set ourselves, he offered to do a set for us. Thank you, Pat.

We have just completed fitting all four doors and on my next trip to Florida I will have the outboard skins spot welded to the inboard waffle skins.

Above:  Original tail wheel gear door

Below:  New tail wheel gear door waffle skins awaiting spot welding

Inboard Main Gear Doors
This week we started pressing the interior waffle skins for the inboard main gear doors (36” x 42”) over machined aluminum press dies. These inside skins are 2024 0 temper, .063 thickness, and have a 2" depth on each of the six pressings.These inside skins were formed by “flow forming”, soft hammers and wooden blocks for the close radiuses.

Above:  Original gear door

The two internal gear door skins are now completed awaiting
final fitting, trimming, heat treating, riveting to the internal
framework and spot welding.

The Kat
“Don’t tell Tom that I’m sleeping or he will make me go back to work.”
— Allison

Quote of the Month Regarding North Korea
“You shoot at us and the game is on.”
— Gen. James “Mad Dog” Maddis

Hurricane Harvey
It has been heartbreaking to see what the people of Texas have and still are going through. We want to sincerely thank the military, the utility companies, FEMA, and the many private  companies and individuals, etc., (from Texas and other states as well) that have unselfishly and willingly pitched in to help by trailering their own boats and off-road vehicles to assist in the rescue efforts. It is wonderful to see the military with such a quick response with their troops, helicopters and special logistical vehicles.  A special thank you to all of these heroes and contributors. May God bless you and the people and animals of Texas.


Happy Labor Day.