AirCorps Aviation has made significant progress with the restoration of the Texas Flying Legends Museum's Republic P-47D Thunderbolt 42-27609. The February/March 2018 progress report from Chuck Cravens details the recent efforts to put the P-47 back in the air. (photo by John LaTourelle)
WarbirdsNews has just received the latest report from Chuck Cravens on the restoration of Texas Flying Legends Museum’s P-47D Thunderbolt 42-27609 at AirCorps Aviation in Bemidji, Minnesota. We thought our readers would be very interested to see how the project has progressed in the intervening two months since our last article on this important project. So without further ado, here it goes!
Remarkable progress has been made on the forward fuselage structure this month. While the guys have spent some time on the final touches to the tail cone, the main emphasis has been building the internal structure that gives the fuselage that curvaceous, immediately recognizable, Thunderbolt form.
Tail Cone
Though the aft fuselage, or tail cone, is substantially complete, there are always little finishing touches that prepare for later tasks, like equipment or systems installation.
Rob McCune’s CAD rendering of the aft fuselage served as a great resource for visualizing how all the parts on the engineering drawings were to go together.
Hunter is getting ready to go inside the tail cone to buck a rivet while Dave waits with the rivet gun. (photo by John LaTourelle)
Hunter works on the elevator lever support station installation. (photo by John LaTourelle)
The tail cone in its fixture positioned correctly in relation to the forward fuselage. (photo by John LaTourelle)
The mounting area for the horizontal stabilizer shows in detail in this closeup shot of the aft fuselage. When placed inside the tail cone during riveting, the nap of the black cloth catches shavings that might otherwise scratch the aluminum. (photo by John LaTourelle)
The green tubular part running transversely across the fuselage at station 321 is the lifting tube. (photo by John LaTourelle)
Here we have a view from the rear of the tail cone. (photo by John LaTourelle)
You can see the rear upper skin forms the very aft peak of the razorback. (photo by John LaTourelle)
One of Rob’s CAD renderings shows the joint between the aft and forward fuselage as a wider former just ahead of the many aft fuselage stringers.
Corrugations
One design element used in the P-47 can be characterized as a carry-over from the early metal airframes dating way back to Hugo Junkers’ J series in WWI and on through the Ford trimotor, many 1930s airframes’ structures, and the Junkers Ju52. That element is corrugated aluminum. The corrugations are there to stiffen the skin in the early examples listed, but in the Thunderbolt it was commonly used on bulkheads inside the fuselage to stiffen those parts.
The use of corrugation in the P-47 shouldn’t be thought of as outdated for the time, though. The technique is still used today: the Piper PA-28 family’s tail surfaces have stamped indentations on the vertical and horizontal tail surfaces for stiffening.
The corrugations are created using a die in a press brake.
Kris works with a corrugated part, using a finger brake to form an edge flange. (photo by John LaTourelle)
A closer shot allows us to see part clearly. (photo by John LaTourelle)
This assembly will be the front auxiliary tank compartment panel. (photo by John LaTourelle)
In this CAD rendering, we can see that particular panel as the lowest corrugated part in the drawing.
The assembly pictured in the last photo isn’t quite complete; it still needs some stiffeners riveted to it, which explains why it looks a little different in the CAD drawing.
Kris continues to make corrugated parts – these are pieces that will become the top auxiliary tank panels. (photo by John LaTourelle)
Greater detail is visible with this close up of the sections of the top auxiliary space panels. (photo by John LaTourelle)
Preparing Parts and Assemblies for the Next Steps
As the fuselage work progresses, assemblies and single parts are constantly being put together, trimmed, and readied for the upcoming steps in the restoration.
Robb files a part to fit. On the bench are a section of the lower aft longeron (the part with eleven lightening holes in it) and the top forward crossbeam for the auxiliary tank area.. (photo by John LaTourelle)
Forward Fuselage
The inside of the cockpit will have quite a bit of visible corrugation.
Dave works on the fit of a fuselage former, sitting inside the main fuel tank area of the lower fuselage.. (photo by John LaTourelle)
This drawings shows some of the fuselage stations. Station 101.625 is between the red marks added to the drawing.
Here is part of the bulkhead at the forward wing crosstie station or station 101.625. (photo by John LaTourelle)
A longer shot lets us see the relationship between the corrugated portion and the rest of the bulkhead. (photo by John LaTourelle)
Another section of the bulkhead awaits installation; it is formed, drilled, and painted on one side. (photo by John LaTourelle)
Robb is working on one of the main longerons.. (photo by John LaTourelle)
Here we can see the part that was on the bench as it looks installed. (photo by John LaTourelle)
Notice the curve as the longeron sweeps upward toward the tail. (photo by John LaTourelle)
On the backside of the station 101.625 bulkhead is a hole where the cockpit ventilator tube connects via nutplates. (photo by John LaTourelle)
Here we can see that the other end of the same longeron extends all the way to the forward wing tie station, 101.625. (photo by John LaTourelle)
The structure produced by this kind of engineering is what resulted in the P-47’s well-deserved reputation for strength. (photo by John LaTourelle)
Clamps and clecos hold the structure together as each part is fitted and later attached. (photo by John LaTourelle)
These fuselage formers are nearer the tail at station 285. Notice the stiffeners riveted to them.. (photo by John LaTourelle)
This view of crosstie fasteners shows the remarkable number of bolts used to hold the wing fittings in place. (photo by John LaTourelle)
At the left is the station where the tail cone attaches; to the right is the rear wing crosstie bulkhead.. (photo by John LaTourelle)
Aaron checks the alignment of a former. (photo by John LaTourelle)
Randy drills the rear crosstie bulkhead for another rivet. This bulkhead is at station 148.375. That makes it 46.7 inches aft of the forward crosstie bulkhead at 101.675. (photo by John LaTourelle)
The large aluminum beams are at the parting line between the bottom half of the fuselage and top half. (photo by John LaTourelle)
Here is part of the bulkhead at the forward wing crosstie station or station 101.625. (photo by John LaTourelle)
This is the backside of the forward crosstie bulkhead. (photo by John LaTourelle)
In this tighter shot, we can see how the structure is attached to the “parting line” beam. (photo by John LaTourelle)
When the basic bottom structure has been completed, the beams will be removed and the top half of the fuselage will be built on the bottom half.
And that’s all for this month. WarbirdsNews wishes to thank AirCorps Aviation, Chuck Cravens (for the words) and John LaTourelle (for the images) for making this report possible! We look forwards to bringing more restoration reports on progress with this rare machine in the coming months.
Wonderful Workmanship!
However I do wonder who has the money for all this or if it is not just another asset investment scheme? Any way, at least it keeps the crafts alive and training another generation of aircraft craftsmen. Amen, brother to that!!
You are so right… It is incredible workmanship. But you have to remember, there are quite a number of people willing to pay for this level of precision. It may be asset investment for a few owners, but Texas Flying Legends wouldn’t fly their aircraft to all corners of America (and even beyond) if that were true for them. These guys want to share their passion for aviation history with the nation, and that’s a great thing!
Wonderful Workmanship!
However I do wonder who has the money for all this or if it is not just another asset investment scheme? Any way, at least it keeps the crafts alive and training another generation of aircraft craftsmen. Amen, brother to that!!
You are so right… It is incredible workmanship. But you have to remember, there are quite a number of people willing to pay for this level of precision. It may be asset investment for a few owners, but Texas Flying Legends wouldn’t fly their aircraft to all corners of America (and even beyond) if that were true for them. These guys want to share their passion for aviation history with the nation, and that’s a great thing!