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!




Wednesday, October 1, 2014

September XP-82 Twin Mustang Restoration Project Update

It has been quite a month!

Tail Sections
For the majority of the past month, most of the crew has been on the final alignment and attachment of the aft fuselage extensions, verticals and horizontal stabilizer. The initial lineup when perfectly, but the microscopic adjustments down to .010 (ten-thousandths - 3 times the thickness of a cellophane  plastic sheet) seemed to have taken forever, but everything is now permanently aligned and attached, and the team has started the final fitting and riveting of the side skins.

Right-hand Aft Fuselage Extension

Left-hand Aft Fuselage Extension

The pulley brackets for all of the primary controls (elevator and rudder), and secondary (trims) are now completed and awaiting final installation along with the four side skins. All four of the elevator and rudder mounting castings and associated matching bellcranks have been final fitted. 

Elevator Push Rods

Right-hand Inboard

Right-hand Outboard

Elevator and Rudder Bellcranks

Both dorsal fins are well on their way to completion. We had to make a few ribs and attachment parts, but the job of alignment and installation of the dorsals went smoothly.

Two other team members have been restoring the multitude of tail wheel gear parts. One cannot believe how many moving parts are in our XP-82’s tail wheels: retraction, extension, steering, oleo, tail door opening and closing, etc. Virtually all the parts needed attention and overhaul to bring them back up to airworthy condition. 

Just some of the tail gear parts

Notice the milling marks on the XP prototype tail gear fitting.

Tail Wheel Oleos

Canopies, Trucks, Opening/Closing Cranks, Windshield Side Glasses
Both hand cranks are now completed and are being installed, and both canopies are ready for installation. All four windshield side glasses are nearing completion. We should have them within a week for routing, trimming and final installation. Even though they look similar to the P-51 series, these canopies and windshield glasses are nowhere close in shape or dimension.    

Canopy Hand Cranks

Outboard Wings
The work on both outboard wings has slowed as we are waiting for the final aileron and flap hinge points for final completion and close-out of the four bottom rear skins.  The remainder of these parts are due here within the next two weeks to coincide with the team completing the riveting of the tail sections. 

Outboard Aileron Hinges

Main Gear Door Opening/Closing Hook Mechanisms
We have received the final forgings for the main inboard gear doors. These parts hold the multitude of push/pull rods that control the positive lock/unlock hooks, which keep the doors securely closed during flight.  They all will be installed this coming month.  Thanks, John, Advanced Manufacturing Concepts.

Inboard Flap Hinges
Both center section flap hinges are now aligned and permanently installed.

Right-hand Inboard Flap Hinge

Coolant Exit Doors,  Header Tanks
Casey Hill, English wheel forming wizard, is due here this week to complete the forming of the two complicated interior coolant exit door skins. Also, both coolant header tanks are now installed, one in each rear fuselage.

Coolant Header Tank

Gun Mounts
The six aluminum gun mounts that will be bolted into the center section are now completed and awaiting installation.  Thanks, Vic, Peres Pattern.

Left: Outboard aileron hinge bearing mounts
Right: Outboard flap push rods

The Katz

"What do you mean you again forgot to get my treats!"
- Allison

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