April/May P-47 Update 2017

Texas Flying Legends
by Chuck Cravens

P-47 Razorback
An angled view takes in the tail cone, covered in protective plastic.  It eventually ends up attached to the forward fuselage at this end.

An angled view takes in the tail cone, covered in protective plastic.  It eventually ends up attached to the forward fuselage at this end.

Update

The main focus for the P-47 project this month was preparation for beginning the fuselage assembly.  In order to do that, a precise fixture had to be created.  We showed photos of the machined flat aluminum plate that makes up the bed of the fixture last month.  This month some uprights were made and installed. Parts continue to be made as materials arrive.

Extrusions for the Structure Arrived and were Sorted

The P-47D-23RA has 250 different shaped extrusions that add up to a total length of 2,573 feet, just short of a half mile of extruded aluminum.

The P-47D-23RA has 250 different shaped extrusions that add up to a total length of 2,573 feet, just short of a half mile of extruded aluminum.

These extrusions are custom ordered and will make up 2683 parts. 

These extrusions are custom ordered and will make up 2683 parts. 

They will be cut into pieces of a variety of lengths from ½ inch long brackets to lower wing spar flangesover 17 feet long (208.39 inches).

The Bottom of the Fuselage Fixture Goes Together

The fixture is taking shape.  The upright arms from the previous image that stick up and have holes bored in them are where the wing attach fittings are bolted to the fixture as the fuselage is built.

The fixture is taking shape.  The upright arms from the previous image that stick up and have holes bored in them are where the wing attach fittings are bolted to the fixture as the fuselage is built.

This view is from the rear.  The tail cone attaches at this point when the appropriate time comes.

This view is from the rear.  The tail cone attaches at this point when the appropriate time comes.

P-47 Parts Meet the Fixture

Upcoming reports will show the progress as the forward fuselage takes shape.

February/ March P-47 Update 2017

Texas Flying Legends
By Chuck Cravens

This is a dimensionally stable, machined, cast aluminum toolingplate commonly called MIC-6 (MIC-6 ® is a registered trademark of Alcoa).

This is a dimensionally stable, machined, cast aluminum toolingplate commonly called MIC-6 (MIC-6 ® is a registered trademark of Alcoa).

Update

This month didn’t happen to have a great many visible changes to the P-47, so we will be brief this time.

Last month we saw the wing attach fittings ready to be magnetic particle tested and cad plated.  Those finished parts are back.  The other main project right now is building a fixture to begin assembling the forward fuselage.

Wing Fittings

These wing attach fittings connect the cross tie that runs through the fuselage to the wing itself. They are machined from billet steel because the original forgings would be cost prohibitive in a small batch. It would take the better part of a million dollars to have forged blanks made for the eight unique parts plus a few spares necessary for one airplane. Billet machining cut that cost by a factor of 30.

P-47 Update

The engineering drawing for the lower cross tie is depicted here. This Republic Aviation Corporation engineering drawing is where the fabrication shop starts the process of creating the finished part. You may need to enlarge it on your screen to read the various notations. If you look carefully , there is a smaller drawing of the part located below and to the left of the main drawing.  This is an alternate form of the part, number 89F11989.  The difference is that the fluted grooves on the edges of the tapered section are omitted.  Since our P-47 had these alternate wing attach fittings, they are what we made.

Fuselage Fixture

The fixture was rendered in CAD before starting.  This is how it will appear when finished.

The fixture was rendered in CAD before starting.  This is how it will appear when finished.

This rendering shows the lower fuselage mounted in the fixture.

This rendering shows the lower fuselage mounted in the fixture.

Another view shows us the forward end of the lower fuselage in the fixture. 

Another view shows us the forward end of the lower fuselage in the fixture. 

Eventually the upper fuselage will be built in the fixture and attached as it is assembled.

Eventually the upper fuselage will be built in the fixture and attached as it is assembled.

January/ February P-47 Update 2017

Texas Flying Legends’
by Chuck Cravens

Careful realignment is always part of reinstallation when using a fixture.

Careful realignment is always part of reinstallation when using a fixture.

Update

In our last update, we showed the tail cone’s initial assembly, disassembly, and finally painting. The vertical stabilizer was at the same stage.

This month those assemblies are beginning to take on their final, permanent form.

The fabrication shop is staying one step ahead so that parts will be ready when needed as the P-47 continues to take shape.

Tail Cone

Vertical Stabilizer

Quite a bit of skinning went on now that the vertical stabilizer has been painted.

Parts for Coming Steps in the Restoration

December/ January P-47 Update 2017

Texas Flying Legends
by Chuck Cravens

Texas Flying Legends
The Christmas season was part of the time period covered by this update so, in honor of the season, I thought I would show a photo that wouldn’t ordinarily make it into an update: This is what an AirCorps-style Christmas tree looks like! The P-47 tail cone is festooned with lights. 

The Christmas season was part of the time period covered by this update so, in honor of the season, I thought I would show a photo that wouldn’t ordinarily make it into an update:

This is what an AirCorps-style Christmas tree looks like! The P-47 tail cone is festooned with lights. 

Update:

In late December and early January, the initial tail cone assembly was finished.  As happens so often in a warbird restoration, that assembly was taken apart to be painted with a protective zinc chromate coating.

We also received some of Rob McCune’s great CAD renderings that show us how the main assemblies fit together.

Renderings

Parts Fabrication

Since there are 23,337 different parts in a P-47D-23, not including the engine, prop, accessories or rivets, it’s no wonder that parts fabrication is a continuous process. That number is about 60% larger than the number of parts you would find on a Mustang. 

Initial Tail Cone Assembly

The tail cone has been in the process of assembly and fitting for quite a while now.  That was finished up this month as you will see in the following images.

Disassembly for Painting

Once everything has been fitted properly, the tail cone assembly can be taken apart for painting.

Reassembly of the Tail Cone

Painting didn’t take long and final assembly of the now corrosion-protected parts began as soon as the parts
were dry.

This CAD drawing shows the fuselage fixture we will be building. 

This CAD drawing shows the fuselage fixture we will be building. 

The tail cone fixtureis complete and has been shown several times but the rectangular section to the left of the tail cone is the fixture we need to build before the forward fuselage can be assembled.

November/December P-47 Update 2016

Texas Flying Legends’ 
by Chuck Cravens

Texas Flying Legends
A view from the other side as Hunter works, there are a lot of those clips to put in! 

A view from the other side as Hunter works, there are a lot of those clips to put in! 

Last Month...

The horizontal stabilizer came out of its fixture.  The disassembly of the fuselage took upmany of the work hours last month as well.

In the restoration shop, the fuselage disassembly process continued into this month. Actual assembly work in November and early December focused on the tail cone. The frames were mounted in the fixture and stringers, brackets, and other parts found their way into the assembly.

The fab shop machined wing mounting crossties and fittings, crash skid parts, and some fuselage fittings. Those will be used as the fuselage progresses.

This Month...

Compact discscontaining microfilm from the 5th Air Force Fighter Squadrons arrived from the Air Force Historical Research Agency. The histories of every squadron that had P-47s during the correct time frame were ordered. 
They include :

•   The 39th, 40th and 41st Fighter Squadrons from the 35th Fighter Group

•   The 69th, 310th and 311th Squadronsfrom the 58th Fighter Group

•   The 340th, 341st , 342nd and 460th Fighter Squadrons from the 348th Fighter Group.

There are several thousand pages on each of seven CDs to look through. Once the pages that cover May through September of 1944 are located in each Squadron’s history, they will be read carefully for clues to our P-47’s war history.

Fuselage Disassembly

Robb and Randy continue work on fuselage disassembly.

Robb and Randy continue work on fuselage disassembly.

This view is from the rear of the fuselage. 

This view is from the rear of the fuselage. 

Wing Attachment Fittings

Tail Cone Assembly

Cross ties and crash skid parts that will go in the forward fuselage are show here.

Cross ties and crash skid parts that will go in the forward fuselage are show here.

They would have been extrusions at the Evansville, Indiana plant where 42-27609 was built. For small numbers of parts as in a single restoration, machining is more economically practical.

As tail cone assembly begins, the forward frames are attached to the fixture.  

As tail cone assembly begins, the forward frames are attached to the fixture.  

The tail cone is oriented vertically in the fixture with the aft most end up. The fixture was constructed using photos from inside the Republic factory for reference.

October/November P-47 Update 2016

Texas Flying Legends
by Chuck Cravens

Texas Flying Legends
Randy works on some of the last rivet placements in the skin.

Randy works on some of the last rivet placements in the skin.

Ryan, Dalton, Randy, and Sam begin the move of the horizontal from the fixture to the bench.

Ryan, Dalton, Randy, and Sam begin the move of the horizontal from the fixture to the bench.

Update on the P-47

Last month we looked into the assembly of the horizontal stabilizer. This month the horizontal, the first large assembly of the project, came out of its fixture. The restoration continued with the start of the disassembly of the fuselage.

The guys are carefully setting it down on the padded bench.

The guys are carefully setting it down on the padded bench.

The horizontal is safe on the bench, ready for some final work.

The horizontal is safe on the bench, ready for some final work.

Brent takes out some Clecoes in preparation for replacing them withspecially made rivets that have a 115 degree head angle.

Brent takes out some Clecoes in preparation for replacing them withspecially made rivets that have a 115 degree head angle.

Randy using a rivet squeezer to get some of the last rivets into tight quarters on the stabilizer.

Randy using a rivet squeezer to get some of the last rivets into tight quarters on the stabilizer.

Special AN Rivet Angle

Republic used a wider head angle than the standard 100 degree AN rivet angle.  The reason this was done was because the wider angle head could be countersunk in thinner Alclad sheetsthan a standard 100 degree rivet. 
In places, the Thunderbolt used thinner skin than many WWII fighters, especially toward the tail.  They relied on the structure for strength rather than the skin to a greater degree than other manufacturers.

Below are excerpts from theP-47 Series Structural Repair Manual addressing the rivets.

P-47 AirCorps Aviation
P-47 AirCorps Aviation
Cross ties that will be connecting the wing fittings through the fuselage.

Cross ties that will be connecting the wing fittings through the fuselage.

The elevator attachment fitting shows here. 

The elevator attachment fitting shows here. 

Elevator Attachment

Another link slides over this fitting and is pinned in place.  It has a horizontal axis for the elevator hinge itself to attach.

Another view of an elevator fitting, this time it is the inboard one.

Another view of an elevator fitting, this time it is the inboard one.

Brad and Randy remove protective plastic.

Brad and Randy remove protective plastic.

All the rivets are permanently in place in this photo and the horizontal is completely finished.

All the rivets are permanently in place in this photo and the horizontal is completely finished.

Fuselage

Now that the empennage is progressing well, the time has come to disassemble and evaluate the original fuselage.

Robb begins the process of removing the fuselage skins.

Robb begins the process of removing the fuselage skins.

Robb drills a pilot hole into the rivet head and then chisels off the remaining part of the head. This is done so that the hole for the rivet shaft isn’t wallowed out.

Robb drills a pilot hole into the rivet head and then chisels off the remaining part of the head. This is done so that the hole for the rivet shaft isn’t wallowed out.

Ryan carefully inspects the structure.

Ryan carefully inspects the structure.

Checking a part number tag is part of the process.

Checking a part number tag is part of the process.

This rear view of the fuselage shows that most of the structure aft of the cockpit has been removed.

This rear view of the fuselage shows that most of the structure aft of the cockpit has been removed.

One of Rob McCune’s remarkable renderings helps us to understand the structural layout of the P-47 fuselage.

One of Rob McCune’s remarkable renderings helps us to understand the structural layout of the P-47 fuselage.

This rendering is a top view of the fuselage structure.

This rendering is a top view of the fuselage structure.

Some of the rear structure we mentioned earlier sits on the floor.

Some of the rear structure we mentioned earlier sits on the floor.

This is the rear side of the “Christmas tree tank”. 

This is the rear side of the “Christmas tree tank”. 

A front side view shows vandalism damage. Thislooks a bit like a shell exit hole but it isn’t; there is no corresponding entry hole.

A front side view shows vandalism damage. Thislooks a bit like a shell exit hole but it isn’t; there is no corresponding entry hole.

The rivets and bolts holding upper half of the forward fuselage have been drilled out or removed.

The rivets and bolts holding upper half of the forward fuselage have been drilled out or removed.

The forward upper half comes up. Hunter guides it as Steve looks on.

The forward upper half comes up. Hunter guides it as Steve looks on.

The guys move the structure carefully.

The guys move the structure carefully.

A fork lift helps in this shot.

A fork lift helps in this shot.

The upper structure is being moved to its ownsupports, separate from the lower section.

The upper structure is being moved to its ownsupports, separate from the lower section.

Down it comes onto saw horses for now.

Down it comes onto saw horses for now.

Texas Flying Legends Museum's P-47D-23-RA Update for November and early December

The P-47 project is starting to pick up as we start to tear down and inspect assemblies that we have. We have also begun making the parts that we have completed CAD models for and know are missing.

We are working with Mike Breshears of Vintage Airframes/Allied Fighters to make some parts he needs but doesn’t have the capability to make. He needs them in the short term and we need them in the long term. Examples are the leading edges  and some belly skins.

We have pulled all hydraulic components and landing gear. Disassembly and inspection of these components has begun to determine what is good and what will need replacement.  P-47 components can be difficult to find, so we wanted to know what is needed sooner rather than later.

Another component we have been sorting through is the propeller.  The P-47D-23 uses the Curtiss four blade steel SPA-3 Paddle Blades.  These blades are hard to find and we fortunately have one set of those and 2 sets of the standard Steel Blades.  We will continue to look for the missing parts to get at least one prop assembly complete and ready to go.  

The stabilizer has been disassembled, inspected and the usable frame members are ready for reassembly.  Once the spars and usable parts are assembled, fitting of new parts like ribs and skins will begin.  It was a big time savings to find the extruded spar caps are in perfect condition as these would  be considerably expensive  to manufacture.  

Work continues on the CAD drawings of fuselage and wing components, this will be vital to production of those parts in the upcoming months.  We, of course, have added the scanner to our equipment list and it has already helped in establishing the models and contours necessary to fabricate the needed  parts.  We have also used the scanner to verify the Horizontal and Vertical fixtures that came from Mike Breshears as part of the Allied Fighters P-47 parts purchase.  We were very happy to learn that the fixtures were very straight and only required minor adjustment, it also verified that our drawings of the horizontal and vertical are correct.

Stabilizer frame parts laid out for fitting.

Stabilizer frame parts laid out for fitting.

Stabilizer parts ready to begin initial assembly.

Stabilizer parts ready to begin initial assembly.

Fuselage fixture from storage in Minot back in Bemidji.

Fuselage fixture from storage in Minot back in Bemidji.

 

The fixture from Mike Breshears was picked up in Minot and I can’t wait to see the fuselage take shape in it later on.

There has also been a great deal of scanning and cad work done to produce skin sections.   

Another use for the scanning system is to ensure that the horizontal and vertical stabilizer fixtures and their attachment points are straight and true.

Stefan scanning a piece of wing tip skin.    

Stefan scanning a piece of wing tip skin.

 

 

The scans facilitate the production of 3D drawing and production of parts goes on at a rate unobtainable in the past.

CAD work on the engine mount

CAD work on the engine mount

Cad drawing of fuselage structural members. Rob McCune is a big contributor to the whole process with his 3D work.

Cad drawing of fuselage structural members. Rob McCune is a big contributor to the whole process with his 3D work.

Cad drawing of fuselage structural members. Rob McCune is a big contributor to the whole process with his 3D work.

From the drawings the process progresses to machining the forming blocks from tooling plastic.  We also received a belly form from Mike Breshears.  He needed the skin section so we made one for him and also 2 for the P-47 project and one spare.

Belly section forming block from Mike Breshears.

Belly section forming block from Mike Breshears.

Rob McCune, our draftsman, also discovered some information about the strange tank placed just behind the cockpit in the top of the razorback area. General George Kenney of the 5th Air Force didn't like how short the combat radius of the P-47 was, so he had his engineering staff devise a couple different methods to extend the range. One was a 200 gallon drop tank designed and built by Ford of Australia. Another was this added triangular tank behind the cockpit.  The tank required cutting a hole in the side and it was only test fitted to a few  P-47's. It ended up giving the plane balance problems because it was too high up in the fuselage and it wasn't self sealing so it became a fire hazard. It was quickly discarded and never used on a large scale. Turns out ours was one of the test models.  

Experimental auxiliary tank location  inside red lines

Experimental auxiliary tank location  inside red lines

Because only a few P-47s were equipped with the tank to test, it is kind of unique.  At some point we will have to decide whether or not to incorporate it in the restoration.

Once the form has been produced aluminum skin can be stretched over it to make skin parts with complex compound curve shapes.

Original part and new stretched skin.

Original part and new stretched skin.

 

History:

Our P-47 arrived in Townsville Australia on May 7, 1944.  It was condemned  at Dobodura on September 18, 1944 and written off inventory on May 10,1945.

 

 The historical research is ongoing as always. So far I have been able to eliminate 3 of the possible 5 fighter groups that flew P-47s in the 56th Air Force.  Those five groups are the 35th, 49th, 58th, 318th and 348th.

The 35th Fighter Group added a mast to the vertical stabilizer to lift their antenna up a foot for better radio reception.  They  were in Morotai, Dutch East Indies by September of 1944.  There is no evidence of an added mast on our original fin and it is unlikely that a war weary P-47 would be flown over 1000 miles from Morotai to Dobodura to be written off.  That eliminates the 35th with reasonable certainty.

The 49th Fighter Group had P-47s for a brief period.. Only one squadron, the 9th FS was equipped with them.  They converted to P-47s in November of ’43 and switched back to P-38s in April of 1944, so were no longer flying P-47s when 42-27609 arrived in theater.

The 318th also had P-47s but were flown off carriers directly to Saipan in June of 1944.  So they were far enough away to rule them out as well.

That leaves the following Fighter Group and Squadron possibilities:

 

Group         Squadron      Dates in  combat

58 th FG    ...   69 FS           2/44-12/45

                         311th FS        2/44-12/45  

 

348 th FG        340th  FS       6/43-3/45

                          341st  FS       6/43-3/45

                          342nd  FS       6/43-3/45

                          460th  FS        9/44-3/45

The 460th is pretty unlikely because of the date they began operations.  All of the serial numbers from 42-27608 through 42-27637 that I can track down went to either the 58Th FG or the 348th FG , so that adds credence to the conclusions.

If anyone has photographs of 42-27609 while she was in service, we would love to hear from you. They would have to be shots that haven't been online since and exhaustive search has been conducted.  If you or a family member served in one of the squadrons listed and you have a picture that shows 427609 on the fin, please contact me at chuckc@aircorpsaviation.com.  We'd happily pay for the photo or for reproduction costs.  It would be great to return this Thunderbolt to accurate wartime colors.


April Shop Progress on the P-47

The guys have been removing all the P-47 parts from shipping containers.  First there was an initial inspection, then the parts were sorted into bins by subassembly.  Then they were stored in racks.

Loads of P-47 parts

Loads of P-47 parts

Opened P-47 shipping boxes

Opened P-47 shipping boxes

Parts sorted and racked by subassembly part numbers.

New, old stock original P-47 main oil tank

New, old stock original P-47 main oil tank

P-47 Razorback Photos