On 31 December 2018, our XP-82 Twin Mustang flew for the first time since 14 December 1949. Although it wasn’t supposed to fly yesterday, all that was planned to do was the last FAA required runway high-speed taxi test, lift off for a second or two and then back down, deploy full flaps and brake to a stop. It accelerated so fast after the planned lift off that Ray, our test pilot, realized that getting it back down and stopping it in the remaining runway would be marginal. So he pushed the power back up and flew for about five minutes.
The unexpected and dramatic acceleration of our XP-82 at 55 inches of manifold pressure occurred because it was approaching three times the horsepower of a single engine Mustang and one and a half times the weight. The XP-82 has 1860 hp each side for total of 3720 hp, compared to 1500 hp for the P-51. Our XP-82 weighs approximately only 1 1/2 times more than a P-51 - 14,700 lbs. compared to 9500 lbs. for the P-51.
The very short gear-down flight showed zero airframe squawks, hands-off no trim required, with all engine temps and pressures normal.
This wonderful test flight came after a 10.5 year restoration encompassing 207,000 labor hours. Many thanks to Ray Fowler, our test pilot, and all of the men and women that made this restoration possible. Thank you, Tom Reilly.
After ten long years, we are ready to fly ... almost. We received our Airworthiness Certificate on Sunday, one day before Oshkosh. This did not give us enough time to fly off the restriction hours (15), and then get a check ride. Tom went to Oshkosh to give a talk on the XP-82 restoration. While there there was a F7F Tigercat that had an apparent wheel failure; the same type of wheel our 82 has. Even though our two wheels passed inspection, Tom insists putting on two new wheels. Then we will have our first flight. (Photo credit: Michael O'Leary Air Classics)
(Photo credit: Weezie Barendse)
(Photo credit: Connor Madison EAA)
Tom's wish to own and fly one is about to come true.
Our XP-82 when it was with NACA in Cleveland, OH being used as an
armament test bed 1945 through December 1949
The end of our ten-year XP-82 restoration project is in sight.
The light at the end of the tunnel is not an oncoming train.
We are down to a rather short punch list with another ten weeks to go. A few of the outstanding punch list items that would have precluded us from making Oshkosh this year are now solved.
Outdoor Gear Doors
Both inboard pressings were delivered to us about three weeks ago and the fitting of these doors I thought was going to be extremely difficult and time consuming. Paul had them fit perfectly within a week and the internal framework is now fit and both have been completed with the spot-welded outside skins.
New outboard gear doors without outside skins
Gear doors with skins
The two tailwheel door retract brackets have been completed and attached. The four doors are mechanically retracted by rods attached to the tailwheel arm structure(s). The two retractable tailwheel assemblies are retracted not by hydraulics but by a 3/16 stainless steel cable running the full length of each fuselage up to a set of pulleys attached to each main landing gear retract arm. When each main gear retracts, each tailwheel is drawn up into its up-locked position along with the doors. On extension, both tailwheel assemblies unlock, gravity extend and cable-latch the down lock. A very unique NAA factory-installed retract system.
Bent and corroded original part with two new ones
Tail wheel retracted (above) and extended (below)
Landing Gear Retractions
We have completed the landing gear retractions and timing valve adjustments that sequence the inboard gear doors opening and closing. The main gear inboard doors are closed with the landing gear in both the up and down positions with timing valves sequencing the proper opening and closing for the gear to pass. A very straight-forward NAA design that works extremely well.
In the following photos the gear will start to retract, then the gear will lock in the up position, then the door will close, then the door will open and the gear will extend to the down locked position. Then the gear door will close.
The last two major items that we have been waiting for to complete our XP-82 restoration are the two brake calipers. This style of brake assembly was used only on the XP/F-82 Twin Mustang series and no other production aircraft, thus none could be found in the surplus market.
Non-airworthy and broken original brake
Two new aluminum calipers are being 3D computer milled
The most serious of these missing brake items were the two small pressure check valve boxes. Pictures are attached. Our main machinist, John, is progressing nicely to have both calipers completed for us within the next week. John was able to 3D print off of one unairworthy magnesium caliper that we got out of the Alaska wreck site recovery and he is well into completing the machining on both new aluminum calipers. BUT, we had no sample of the small pressure check valve boxes to copy. The big problem was that the entire brake assembly was manufactured by Goodyear and the XP-82 parts books did not give us any breakdown or part numbers of any of the associated Goodyear brake parts. Thus we had nothing we could take apart and copy on the two pressure check valves.
Last week, John Soplata, the grandson of Walter and Margaret Soplata, who found for us the second needed wheel in the cellar of the house, discovered a complete XP-82 brake assembly WITH one pressurecheck valve. The entire brake and check valve has been shipped to us FED EX. Now having both brake assemblies, all the original pistons, springs, depth indicators and slave cylinders can be salvaged out of both original brake packages. The two original calipers are cast out of magnesium and due to corrosion they could not be made airworthy. So, along with the two new calipers being machined, all we have to do is duplicate the one small check valve box which will be completed within two weeks.
Not having these pressure check valves was a grounding item. A very time consuming bump in the road was avoided.
Items on the “to complete” punch list.
1.After this coming week’s hard two-hour engine and propeller run-ins (we do not expect any problems), the entire XP-82 airframe will be lightly washed down with aluminum etch and a soft Scotch Brite pad to blend out any small scratches. This will highlight the color differences between the three different alloys of aluminum that had been used on the exterior of our XP-82. If one looks at the original pictures of our aircraft during its prototype first flight, you can definitely make out these color changes.
2.We have received all of the stencils for all of the painted markings that are all over the airframe. These will be applied after the etching.
3.We have now exceeded 202,000 man-hours invested in this XP-82 restoration. So if nothing goes bump in the night, we will make Oshkosh this July with time to spare.
The left-hand, right-hand and center section flaps are now permanently installed and adjusted to their four different degree stop positions
We were able to find the seven radios that were originally in our XP-82, including all of the Cannon plugs. For authenticity we have duplicated the exact color wires that we soldered back into the original plugs. We still have one more Cannon plug to solder, the antenna wires that plug into the radios and tie ups to complete the original installation.
All four ailerons are also now permanently attached. Randall now has the range movements, balance, cable tensions and stops set to match each stick in both cockpits.
Rudders and Elevator
Both rudders and the elevator are now permanently installed. Range movements, balances, cable tensions and control movements have been done and synchronized to both sets of pedals and sticks. This was quite a time consuming job getting all four pedals matched to each other and to both rudders, but now they are completely done. All turnbuckle safety wiring is now completed.
Leading Edge with Gun Ports
The entire leading edge is now totally attached. This job took Paul and Randall a complete week due to the final riveting and the hundreds of screws and nut plates throughout the forward spar.
Right forward of the left-hand tail wheel there is a 3” round hole in the left side of the fuselage that houses a mounted Starrett level that is visible to set the pitch (tail up/tail down) of the two fuselages when doing a weight and balance. In the 1944 North American Aviation XP-82 plans it showed a very detailed picture of the level with part number and the mounting structure. I instructed Weezie to contact Starrett to see if they had one of these levels in their museum that we could get for installation in our XP-82 to make the restoration as original as possible. Within a few hours, she found an identical brand new one in stock at Grainger in Orlando. What were the chances of finding a Starrett level absolutely identical to the 74-year-old parts book drawing?
Both outboard wings are now totally bolted and torqued, 300+ internal-wrenching bolts in all. All of the fuel feed and vent hoses are now installed, tanks filled with fuel and all connections and pumps tested for leaks.
Pitot Static Systems
The pitot (air speed) and static (neutral air pressure) systems going to both cockpits are now completely hooked up and pretested for leaks. A technician from a FAA-approved repair station facility will come to give us our required altimeter, transponder and encoder (tells ground controllers your altitude, air speed, etc.), pitot instrument and static air going to each air speed, climb and altimeter instruments for accuracy sign-offs. I cannot do these final checks and sign-off as a FAA-licensed avionics facility must do these tests.
Engine/Prop Test Runs
Since October we pulled our XP-82 outside two more times for engine/prop test runs. Each time we would tie down each tail to strong tie down anchored rings, add sand bags to the top of the horizontal to stop the tail from lifting during hard run-ups.
So far, I have brought the power up on each engine to 1500 rpm, about half power and test- cycled the props. I will start the prescribed three-hour run in schedule dictated by Vintage V12s, the company that overhauled our two Merlin engines. To date we have 1.5 hours time of ground runs and system checks on both engines with no squawks.
Weight & Balance (W & B)
A few weeks ago a weight and balance company from Lakeland, FL came to perform the required W & B on our XP-82. The wood underneath the propeller hubs is not supporting anything; they are just there for a safety to prevent a nose over.
14,979 lbs. with 400 lbs. of sandbags on the horizontal stabilizer
We were able to locate two NOS ID-42A/APS-13 radar indicators. These are installed just below the pilot and co-pilot’s glare shields. When the light comes on it lets you know that an uninvited guest is on your tail.
“Can I have a B-25 ride …
can I, can I?”
B-25 Mitchell Panchito who owns
Who owns who??
Happy Memorial Day from Tom & the XP-82 Crew
Quote of the Month
“The object of war is not to die for your country but to make
the other bastard die for his.” — Gen. George S. Patton
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.)
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.
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.
“With me siting here, be careful where you cut with that large pair of shears that you have in your hand!”