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When Hollywood Ruled The Skies - Volumes 1 through 4 by Bruce Oriss


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PostPosted: Sun Sep 16, 2012 11:50 am 
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Posts: 117
Location: San Marcos, Texas
We have a new plane!

The Centex Wing has adopted a BT-13A, formerly flown by the Big Thicket Wing out of Cleveland, Texas. The plane was being flown from Cleveland to Midland in 1999 when it experienced and engine failure. By an odd coincidence, it went down fairly close to its new home in San Marcos. It was dismantled and trucked back to Cleveland where they started a restoration. The project overwhelmed the unit and they put it up for re-assignment. At the Cobra Den, we have lots of volunteers with T-6 experience and had just completed the P-63 project, so we got our ducks in a row and requested the plane from Midland. What is that old saying? Be careful what you ask for...

Billy Parker and I visited the BTW in March to get a look at the project. They had done a lot of very good work, but there was still lots to do. On top of that, their hangar had been damaged by a hurricane and it took three years to get the insurance worked out and get a new roof on the place, so everything was pretty dirty. Here is a shot of the fuselage:

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And the forward instrument panel:

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After we were granted possession of the aircraft, I put together an 11 man team with a small fleet of trucks and trailers to move the plane to San Marcos. The BTW folks had it ready for us and were a huge help loading everything. We needed several men to load the wing center box safely:

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The engine went as a QEC and was a good load for one of the pickups:

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And the fuselage was a perfect fit for our largest trailer:

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We got everything back safely and set about cleaning all of it and storing it so we didn't have the hangar cluttered or obstructed. That took a couple of days.

Many of the parts we could see needed to be removed, cleaned up, repainted, and put back on... we thought.

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The work turned into a frenzy as we removed layers of parts and the project has turned into a serious restoration. We are now going down to the frame and rebuilding a plane around it. Volunteer interest has been greater than I expected and work is progressing faster than I could have imagined. After three good workdays, the firewall is off and only a few pieces remain to be removed from the frame. Here is how it looked at quittin' time yesterday:

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Sure hope we can remember how all that stuff goes back on... Anyway, we will remove the tail section and strip and paint the frame, after it is inspected closely. The tail was repainted externally by the BTW, but we will clean and prime the inside and the tailwheel bulkhead. The BTW tried to seal fuel tanks. We are going to have the wing center box and the wings stripped of paint, then we will open the tanks and clean them out and remove all of the old sealer. We will reseal the tanks and close them up.

The BTW had acquired another engine, a 985-AN-3 military version. We will have it IRANed, though we're still discussing other options. All seals and rubber hoses on the aircraft will be replaced. All instruments and accessories will have to be checked out and repaired or replaced. There is LOTS and LOTS to do. But we're pretty excited about it and are looking forward to the work. So far, the only unserviceable part we've found is the pilot's seat. We plan to have new instrument panels made, the front one for sure, and update some of the instruments. Many of them were definitely original.

I know there are a few of these around, so any of you WIXers that have experience or advice to share, or know where parts might be found, I'd really appreciate hearing from you. The Tora Vals are all BT's, but they're all modified. This plane started its life as a Navy BT-15. In 1988, it was converted to a BT-13A, a Pratt 985 powered plane with a 12 volt electrical system. We plane to keep it exactly that way. It has a two position prop control - fine and coarse. We'd like to know about installing a prop governor on the pad on back of the engine. The TCDS says we can.

We'll keep posting updates, as this is moving quickly right now.

Thanks!

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Ray Clausen
Maintenance Officer
Centex Wing of the CAF


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PostPosted: Sun Sep 16, 2012 1:11 pm 
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:drink3:

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PostPosted: Sun Sep 16, 2012 1:13 pm 
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Ray: I'd suggest that you set the center setion right side up on some structure, level it in roll and pitch and do a multi-day leak check on it as early as you can. Plug all of the lines except one on and set it up with a capped fill stack.....sort of like a manometer on the one line. If you have any leaks within either tank, you are better off pulling the bottom skins one at a time and cleaning out all the old chromate paste and using fresh polysulfide type sealant on the tank. Reshoot the skins on with wet sealant and it will never leak again. Do the same thing with the acess panel rings and nutplates and when you are done, you will be miles ahead. A couple of good sheet metal guys and not finding any damage or bad skin or ribs will take a hundred or so hours to complete the task. It's also easy to use the poly sealant to make formed in place gaskets for the access panels too. There are a few tricks and I'd be happy to share them if you need to open the tanks up for resealing.


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PostPosted: Sun Sep 16, 2012 5:10 pm 
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Location: Madison, MS
In order to go from a 2 position prop to a constant speed, you'll have to change out the restrictors in the crank shaft. Many times, this requires removal from the engine to gain access to the back of the prop shaft. Also, that airplane has a BT-15 motor mount which has a different engine angle than a -13 motor mount, which means that it is for a R-975 vs R-985. The carburetor is angled differently on these engines. This means that the float hinge is angled differently and with an uncoordinated turn (such as taxiing on the ground), the engine will go very rich and cause a loud backfire, especially with a power (throttle) change.

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PostPosted: Sun Sep 16, 2012 8:17 pm 
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Joined: Thu Aug 20, 2009 9:24 pm
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Location: San Marcos, Texas
Wow! Two great responses, right off the bat!

First, for Cvairwerks. The guys at BTW built a fantastic fixture for the wing center box that attaches to each end and allows it to be turned almost completely around in either direction. Two people can rotate it with one hand each. We put casters on it to allow us to roll it around the hangar with ease. Here is one end:

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I had already made the decision to pull the panels and thoroughly clean out the inside of the tanks and reseal them. I'm interested in knowing more about the sealants available and what is best to use and why. A repair was made to the inboard tank wall and we are going to remove that entire wall and replace it with a single piece of new aluminum. Your tips and advice would be very much appreciated.

For skymstr02, that's the kind of info I was hoping for. I'm studying now but experienced guidance is best. One of the engine related decisions we're pondering is whether to overhaul this engine or turn it in as a core on an engine that is set up for a governor and is ready. This BT was converted in 1988 and was flown for about 12 years with a 985, so I believe we're OK with the engine setup. Most of our pilots want the prop governor, though.

Thanks!

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Ray Clausen
Maintenance Officer
Centex Wing of the CAF


Last edited by Ray Clausen on Thu Sep 20, 2012 12:46 pm, edited 1 time in total.

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PostPosted: Sun Sep 16, 2012 8:54 pm 
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I've reskined one. Clean the old sealant out, fix corrosion, primer inside with BMS10-20 primer (Boeing fuel tank primer). Reseal with polysulfimide sealant. The DD rivets are unobtainium (which is good), use E type rivets which are a direct replacement and don't need to be heat treated and put in an ice box. The E rivets are room temperature use.


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PostPosted: Mon Sep 17, 2012 8:36 pm 
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Location: San Marcos, Texas
Another busy day at the Cobra Den! Just a couple of pieces of conduit left to remove. The frame, center box, wings and possibly the tail will be stripped of paint in the next day or so.

Image

We will bring the engine from the storage unit Wednesday and begin removing the accessories. When we get the engine off of the engine mount, we will get everything cleaned up and tested. Now all of the pieces and parts must be cleaned and reconditioned. Many of the pitot/static tubes were corroded and fell apart when we were removing them from the frame. Still have lots to do but the project, so far, is moving way faster than anticipated. Professor Murphy must be on his way....

Thanks!

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Ray Clausen
Maintenance Officer
Centex Wing of the CAF


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PostPosted: Tue Sep 18, 2012 11:21 am 
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Great news! As busy as you guys are, thank you for taking the time to share the story & photos.

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