Thursday, January 1, 2015

December XP-82 Twin Mustang Restoration Update

 What a year 2014 has been for progress 
that the XP Team has made on the 
XP-82 Twin Mustang Project.

Just looking back to last 
December’s photos really shows 
what has been accomplished this year.

Center Section
All the gear door castings and link rods are now installed with the exception of the two aft door hooks and hook mounts that we should have any day now.  Gear door up-lock casting mounts, hooks, bell cranks and push rods are pictured in numerical order starting on front spar.

Left-hand wheel well, forward gear door up-lock hook mounted on forward spar

Left-hand 90 degree door up-lock bell crank mounted on forward spar

Center gear door up-lock mount with one push rod coming from 
forward spar and one push rod going to the middle spar

Aft gear door up-lock mount with push rod coming from center gear door mount

Both emergency gear up-lock release mechanisms are now installed and cables run.  These up-lock releases can be operated independently by either pilot through a common cable to release the gear doors and up-locked landing gear by a pull handle mounted under each instrument panel. Both gear will then gravity fall to down-lock position.

All of the 3/32 stainless steel cables that run through the center section from each throttle quadrant are now installed and rigged. These sixteen cables, eight running from each side, synchronize the throttle and prop control levers mounted in each cockpit. 

Also, the six one-inch diameter five foot long control rods that transfer and synchronize the elevator and aileron movements between both pilots are now installed pictured below the cables.

And at last, the two remaining (out of 20) fuselage-to-center-section attach fittings are now permanently installed. Each fuselage is attached to the center section with ten huge NASA bolts bolted down through and into barrel nuts mounted in fittings attached to the forward, middle and aft center section spars.

The final installation and rigging of the opening and closing crank and cable mechanisms for each canopy are now completed.  (Two of the very few parts in the 82 that are the same as a P-51.)  Both under-canopy aft closeout skin panels and phenolic rub strips are now completed and installed.

Aft Fuselages
All of the rudder, elevator and balance trim cables are now run through numerous pulley banks, installed and up to tension. As you can see, not that easy to get to.

Both rudder lower side skins (four) and tail light receptacles are now completed.  Both lower rudder boots that were mashed beyond recognition are now back to final shape and fit, awaiting special English wheel rollers to roll out the final small dents.

Dorsal Fins
Both dorsal fins are well on their way to completion.  All of the parts are remade and fit, awaiting final riveting.

Fuel check valves, before and after. New nipple fittings are on order

Wings / Flaps / Ailerons
The remaining flap hinges, mounts, bell cranks and arms have now been completed and painted, awaiting installation. 

The aileron combination sector/arm/hinge mounts (25 in all)(23 pictured) have all been delivered to us from two of our sub-contract machine shops and are being fit.

Tail Wheel Retract/Extension Mechanisms

We have just started to get full time into sorting out what we still need in the tail wheel assemblies. The majority of the steering parts that were originally magnesium didn’t survive the sixty years of element exposure very well. We have two machine shops just starting the duplication process of all the parts that are still required.

The Katz
Tom explaining to Rivet how the rudder adjustment rails are assembled.

Saying of the Month
'When flying try to stay in the middle of the air. 
Do not go near the edges of it. 
The edges of the air can be recognized by the appearance of
 ground, buildings, sea, and trees. 
It is much more difficult to fly there."

- W.W.II Undergraduate Pilot Training Sign

The entire XP-82 team would like to wish everyone
 a very Merry Christmas and a 
Happy, Safe and Prosperous New Year.


Monday, December 1, 2014

November XP-82 Twin Mustang Restoration Update

What a Fabulous Year 2014 was for Our 
XP-82 Twin Mustang!

Aft Fuselages
Part of the team has completed riveting of the all of the little hard-to-get-to places on both aft fuselages. They are now concentrating on completing both dorsal fins. 

With the exception of the completion of the riveting work on the aft fuselages and dorsals, the remainder of the team has been working on completing the multitude of systems and small-to-complete jobs. 

Center Section Gear Door Hooks

The up-lock mechanism for activating the gear door up-lock hooks is quite complicated with the amount of moving parts that it has, but very dependable. The mechanism is controlled by one hydraulic cylinder on each side mounted on the forward spar for the forward hook, and then transitioning all the movements through a number of bellcranks, push rods and levers to actuate each aft hook mounted on the center spar. Two team members have spent the entire month locating each casting (ten) that holds the bellcranks, etc. These bellcranks and mounts are all interwoven with the hydraulic lines and wiring harnesses. Pictures of the completed systems will be in next month’s update.

Emergency Up-Lock Releases
In the XP-82, and all subsequent models, there are landing gear up-lock emergency releases controlled by a pull handle, one in each cockpit, that will unlock the main and tail gear and allow the gear to free fall without hydraulic pressure to the down position and positive lock. These back-up safety factors are in place in the event of battle damage to the hydraulic system or the normal gear down actuation system. 

There is an incredible number of pulleys in both wheel wells changing the direction of the cross-ship pull cables and releases. The NAA engineers who designed these complex gear door hook and emergency release systems deserve to take their hats off and take a bow.

Control Cables
All of the primary and secondary flight control cables, chains, pulleys, bellcranks, push rods, etc., are now installed with the exception of the final completion of the trim and balance cables, which will be completed this coming week.

Rudder Pulley Chains and Sprockets are now installed

 Elevator Pulley Chains and Sprockets are now installed

Rudder and Elevator Trim Tabs
The installation of the hinge blocks, new bearing mounts with new bearings, and three trim tabs are now completed. Finding the N.O.S. needle bearings for the bearing mounts has been a challenge, but I think we have bought every last one that was available in the world. We replaced the magnesium needle-bearing mounts and machined the new ones out of 7075-T6 aluminum, giving us a much higher safety factor due to numerous known in-flight trim tab failures. 

7075 T-6 Trim Tab Hinge Blocks with New Bearings

Both Rudder Trim Tabs are now installed

Elevator Trim Tab  is now installed

The team has completed the remaining items on the elevator, i.e., elevator control arms (two), counter weights, close-out panels and the final fitting of the elevator trim tab. We were required to add a small amount of extra counter balance weight to offset the additional weight of the trim tab 7075 fittings that we exchanged for the lighter original magnesium fittings.

 Right-hand Elevator Control Arm with Counter Weights installed

Note: All aircraft control surfaces must be precisely balanced as per the factory data so that the control surfaces, i.e., rudder(s), elevator(s) and aileron(s), does not flutter in flight like a flag on a pole in a heavy wind. A flutter in a control surface during flight is extremely dangerous. Thus our balance calculations must be perfect.

Aileron Hinge Points
The four special machined aileron hinge points that we need are nearing completion at one of our sub-contract machine shops. These are the main hinge point attaching-and-actuating fittings that attach the ailerons to the trailing edge of the wings.

We expect to receive these fittings and have them installed during December or January.

Canopies / Windshields / Aft Fairings
The final adjustments of both windshield bows to match the mating canopy bows has now been completed. Both center windshield glasses are now permanently installed, awaiting the delivery of the four windshield side glasses that were completed and shipped to us this past week. The final fitting of these side glasses will be completed by the end of December. A picture of the completed windshield assemblies will be in next month’s news release.

The aft canopy fuselage fairing located under the canopy is now completed on the left-hand fuselage and well on the way to being completed on the right-hand fuselage.

Left-hand Under Canopy Fuselage Fairing (above) is now complete.

Right-hand Under Canopy Fuselage Fairing

The P-82 series has an incredibly complicated brake system that is not fitted on any other known aircraft type. Thus replacement parts are impossible to come by. We recovered one main brake caliper out of the Fairbanks scrapyard parts that had been exposed to the weather for 50+ years. It appeared to be in terrible shape, but a couple of weeks ago, I decided to try to take it apart to expose the internal hydraulic pistons just to look at their condition. To my surprise, all three of the caliper hydraulic cylinders and bores were in perfect re-buildable condition. 

This leaves us with only one caliper to come up with. Pat Harker has machined new ones for his F-82E in Anoka, MN, and we will talk to him about him supplying us with a newly manufactured one.

Newly Machined Inboard Aileron Sector Controls

 Newly Machined Flap Push Rods (above) and Matching Threaded
Flap Push Rod Fittings (below)

The Katz

“Where are my helmet and goggles? 
Crank up the engines, I’m ready to go fly.”  
-- Allison

 Hope everyone had a Happy Thanksgiving.
Wishing you a very Merry Christmas and Happy New Year!

Tom and the XP-82 Crew

Sunday, November 2, 2014

October XP-82 Twin Mustang Restoration Update

October was a fabulous month for our XP-82 Twin Mustang

Aft Fuselage Extensions/Dorsal Fins
The final microscopic alignments and attachment of the aft fuselage extensions have now been completed along with all of the primary and secondary flight control pulley brackets, many phenolic cable guides and tail wheel attachments. The team is now into fitting the two dorsal fins on the top of the aft fuselages where they flare into the vertical stabilizers. 

Some of the many phenolic cable guides that run through the aft fuselages

Dorsal fins being fitted

Canopies and Windshields
Both canopies are now permanently fit and attached.  The jettison system for the canopies has now been final adjusted so that all three releases on each canopy release simultaneously.  Both windshield frames and glare shields are now trimmed and permanently fit awaiting the four windshield side glasses. A second team is also fitting the fairings that fit underneath the aft section of both canopies. These fairings seal the canopies to the fuselages as the canopies roll forward. 

Aileron Hinges
The fitting of the ailerons to the XP wings is going along smoothly. We had to remanufacture all new aileron hinge fittings on the four ailerons – the XP has four ailerons and the P-51 has two – and all new hinge points that mount on the wings. We also had to machine the new gap seal extrusions that are on the upper and lower skins on the trailing edges of the aileron bays.  Also, both of our outboard flap hinges have been completed and are being located on each wing. 

Outboard flap hinges

Outboard aileron attach points

Both heat exchangers are now completed and have been delivered to us.  Thank you, Martin Radiator. 

The two aileron actuating forks have now also been completed, and the last remaining items we are waiting on for aileron controls are the four cable sectors, two mounted in each wing. The sectors are the control wheels holding the aileron cables that control the up and down movements of the ailerons.

Gun Mounts
All twelve gun mounts are now installed.

The Katz
First of all, The Katz would like to send a special “Thank You” to The Katz Fan Club in Pittsburgh, PA, for sending them a nice box of Temptations treats.  They are their favorite.

 They also had a great time trick-or-treating and hope everyone else did, too!