August/September Dakota Territory Air Museum P-47 Update

Grey protective felt has been attached to the forward fuselage for protection as restoration continues.

Update

The P-47 is progressing nicely. This month we will look at some fabrication shop work, fuselage and cockpit restoration progress, and several details of the wing restoration.

Fab Shop

It has been a while since we highlighted fabrication shop work, but parts are constantly being created as they are required by the restoration shop.

The aileron trim tab tube inner control (and corresponding engineering drawing) made to the drawing specifications in the AirCorps fabrication shop.
The P-47 has many extrusions and quite a few need joggles formed in them. These are dies made to form joggles in wing extrusions.
Steve made the double hook spring latch arm and pin assembly to replace the original rusted one on this ammunition feed chute.
Another view of the ammunition feed chute assembly.
Jacob uses the 1940’s 1500 ton Dominion press to form a shroud for the turbo supercharger ducting.
Here is the part after being formed in the press. It is part no. 89F11924, former assembly shroud, station 232 1/2.
That station is just ahead of the turbo supercharger and the two turbo air ducts join just aft of this shroud; then feed exhaust gas
into the turbo supercharger to drive the turbine wheel.

Fuselage and Cockpit

Aaron continued working on cockpit installations this month. One of the major items was the main switch box.

The panel with the black rubber grommet is an original panel.
The knob that says “To Open Pull” is the fresh cabin air control.
This is the recognition light control box.
The drop tank/bomb release control panel has been completed.
The main switch box ready to be wired.
Here is the switch box with the face plate, switches, and dial knobs installed.
The back side of the main switch box has many terminal points for the wires coming in and out of the box.
Aaron holds the main switch panel that he has restored.
Here is a closer view that shows the graphic lettering well. The indicator lights, ammeter, switches, and knobs have all been installed.
This is the face of the Curtiss Electric propellor control box.
Inside the propellor control box are the relays for controlling the prop.
The switch with the red safety cover is the arming switch for the guns and gun camera.
As the label says, it can be set for camera only or both guns and camera.
The area of the cockpit holding the gun and camera arming switch, throttle quadrant, landing gear control, and trim box
assembly is nearly complete. Installation of the main switch box (lower right) still needs to be completed.
The round assembly with the red knob is the oxygen diluter control.
The message bag strap has been installed. In WWII these were a bit of a holdover from earlier days before reliable air to ground radio
was perfected. The message bag was a weighted bag used to drop messages to troops on the ground or to airfields.
This is a pilot seat mount attachment.
There are three mounting spots on the armor plate for pilot seat attachment. This is the upper mount.
This image shows both lower pilot seat back attachments.
The cockpit enclosure rail and roller are in place.
The oxygen filler compartment pan assembly connection has a clip that
would hold an adapter to enable using British charging equipment.

Wings

Creating a new set of wings is a complicated task that has been ongoing for months now. But progress is made every day.

The ammunition box area has been riveted permanently, viewed here from the top side of the left wing.
This angle of the left wing shows landing gear bay reinforcements.
The black rubber grommets will protect a variety of lines and wires.
Starting at the top and moving clockwise, The top grommet will house a
flap hydraulic line, the smaller oval grommet to the right will hold the aileron
trim tab controls, the lowest oval grommet is for another flap hydraulic line,
and finally, the bottom left round grommet will hold electrical wiring.
The complexity of the wing is evident in this top view of the upper right wing structure.
Progress continues on the ammunition bay door.
The outer end (left) of the leading edge curves into the wing tip as part of the semi-elliptical wing shape of the P-47.
The left leading edge is undergoing its final fitting before riveting.
Here is a close view of how the wing fixture holds the leading edge in alignment.
The large rectangular openings in this reinforcing plate are where
the ejection chutes for the empty cartridge casings will attach.
Here, an ejection chute awaits installation on the inside face of the reinforcing plate.
Clecos hold the wing leading edge in place.
Here is a view of the entire left wing structure.
Corey back drills a hole for a bottom skin reinforcing plate.
This is the bottom skin reinforcing plate with access panel holes.

Southwest Pacific Radio Research

One of the interesting facets of the restoration of P-47 42-27609 is the radio equipment, because the mounting had to be changed to accommodate the Christmas tree tank. The tank was placed where the radios originally mounted.

42-27609 had 3, SCR 274 high frequency transmitters in the fuselage when it was recovered.

Despite being reequipped with SCR 274 comm radios, the airplane contained a terminal strip for an SCR-522, which wasn’t used for SCR 274 installations. It also had a BC 966 IFF (Identification Friend or Foe) unit.

The BC 966 was normally used with an SCR 522 comm radio, so it seems that 42-27609 left the Evansville factory with the very high frequency SCR 522. At the time it arrived in Townsville, Australia, the Fifth Air Force was using the high frequency SCR 274.

Since the P-47 had SCR 274s installed, they were undoubtedly installed upon its May arrival in the SW Pacific theater.

The receiver rack and custom field mount are located where the clecos show (left center).
The terminal strip for an SCR 522 installation is at the right center.
This image shows the original terminal strip for the SCR 522, and the restored replacement.
On the back side of the original terminal strip, an
Evansville factory worker named Stone signed the part.
His signature has been duplicated on the replacement.
The new terminal strip as installed in the field modified mount in the fuselage.

During the time span of 42-27609’s service, a June 16, 1944 Fifth Air Force order came out, requiring the squadrons to remove the Christmas tree tanks. There were three primary reasons for the order. One was because of the fire hazard they presented, the second was to facilitate the installation of VHF radios, which would be SCR-522s. The final and perhaps most important reason, documented in James Curran and Terry Poprovaks’ fine book, Check Six, was “Aside from the supposedly better communication thus afforded, such a change was essential in order to communicate with naval aircraft.”¹ This modification is also documented in the squadron histories of several 5th Air Force squadrons.

This conversion back to the SCR 522 VHF radio was never done to 42-27609, nor was the Christmas tree tank removed. Because that is true, it is unlikely that 42-27609 saw actual combat after July of 1944 when those changes were implemented at squadron level.

¹^{James C. Curran and Terrrence G. Popravak,Jr., Check Six, (Casemate Publishers, Pghiledelphia and Oxford,2015) 141}

BC 966 rack in foreground, the rusty one on the far end is an
SCR 274 transmitter rack. Mid left, SCR 274 receiver rack.
SCR 274 custom field rack (center) held 3 transmitters.
Another view of the SCR 274 TX rack and BC 966 rack from the other side.