B-29 Antenna? Transmitter? Receiver? (SOLVED!)

[Geschirr]

What is this antenna/transmitter/receiver... on the nose of early B-29s? The bulge on the nose halfway between the landing gear doors and the window panes.
These B-29s are in India and were some of the first built by the Wichita Plant and deployed to India in April-May 1944. It seems like some early B-29s had these bulges, and further production B-29s did not, but still had the panel. Later B-29s had the panel removed completely. See last photo "Fast Company" for panel without the install.

I've looked through B-29 manuals from 1943-1945, looked at dozens of WWII allied radio antennas, receivers, IFF... etc
This site had some great info (Starboard side antenna descriptions), but none that explained what it is.
Any help at identification is appreciated.

Thank you!

 

[EAIAnalog]

Using the tail number from the 3rd photo, 2-6323, Joe Baugher's s/n database shows it was a tanker flying the Hump from India to China. Which explains the background of the photo. The nose art on the other photos all have camels, which I assume are indications of a Hump run. The position of Item X places it underneath the cockpit floor, below the pilot's control board. The Fast Company photo shows 2 pitot tubes below and aft of the Item X patch. Engineering drawings put them directly below the pilot's knees. On the other side of the hull behind Item X run all the control surface cables, some emergency bomb door release cables, and a few other cables. So it's crowded, but if Item X is underneath the pilot's control board, there may be a fair amount of space. Since the engineering drawings don't show Item X, I assume its installation was a field modification.

Each bomb bay could hold 2 auxiliary fuel tanks, each with 640 gallons capacity. So the total capacity in the two bomb bays would be 4x640 or 2560 gallons. Avgas weight is around 6 pounds/gallon, so the bomb bay gas would weigh approximately 15,360 pounds. Within the bomb load limit. To put it in perspective, each wing of a B-29 holds about 2735 gallons of gasoline. So to fuel a B-29 in China would require 3 B-29 flights from India.

To speculate: flying a loaded B-29 over the Himalayas might have posed some problems that Item X helped resolve. These B-29s are equipped with radar, so that would be a help also. If this is a radio installation, why place it there. I would think putting it closer to the radio operator on the starboard side would be a better idea. I haven't looked for photos of these aircraft from the other side. If there is a duplicate installation on that side, maybe Item X worked in pairs.

 

[ThomasP]

There were various ELINT radar and radio search systems that used similar antenna covers. To me the antenna cover in the first picture looks like the AN/APR-2 type, or similar. It could also be for the APT series of jammers which used similar antenna arrangements.

The image below is the stand alone AS-26/APR-2 antenna with its associated dome. There were variants of the installations and domes that allowed a blade/rod and cone type in echelon, I think also for the AN/APT-2 and similar jammer setups.

 

[Geschirr]

Thank you all for the replies! I figured it was used for some kind of guidance or for tracking radio beacons along the Hump. I don't think it was used in any sort of ELINT function because 42-6323 was converted to a tanker in May 1944 and wouldn't be seeing any combat other than transporting fuel to Kwanghan Field China (A-3 for the 444th BG).

Thomas P, that radome looks like a close match, if not exact. I agree that other types of antenna could be go inside as it was just a cover.

I was wracking my brain, knowing I'd seen that shape on another bomber and then I realized it was similar to the one used on some PB4Y-2 Privateers, I could be wrong. This type of antenna was the AN/APS-2 S-BAND Search Radar & Beacon (according to Alan C. Carey's book "Consolidated-Vultee PB4Y-2 Privateer...") he just lists it, but doesn't give a representation of where it is. In the below photo it is stated as a "DF (direction finding) Antenna." Here is right side of the "Eddie Allen" with another antenna coming out the side. Thank you all for you help, hopefully we can figure this out

 

[ThomasP]

The APS-2 used a directional (ie trainable) Ø29" parabolic antenna, and was a single unit installation. As far as I can find the APS-2 was used as a stand-alone unit, and not associated with other antenna types. It might be in the dome under the nose of the PB4Y in the images in the above post?

I think the blade antenna on the B-29 in the above post is the APR-2 blade antenna I mentioned in my first post. The AS-25 blade antenna associated with the APR-2 was 21" in total length with about 16-17" extending out of the fuselage. While the APR-2 was intended for ELINT purposes, via search & locating of enemy transmitters, it was also used for navigation by homing on known transmitters (enemy or friendly). The AS-25/APR-2 blade antennae were used in pairs, one on each side of the fuselage.

 

[EAIAnalog]

Here are two ECM antennas installed on T Square 54 at the Museum of Flight in Seattle. They are representative of the AT-38A/APT antenna. From left to right you have the antennas, the aft bomb bay, and the radome.

 

[Geschirr]

It is an AN/APR-4 Radar Intercept Receiver with a CW-26 cover. The AN/APR-4 was built by Crosley an improvement over the AN/APR-1 made by Galvin Inc (later Motorola).
Further reading: AN/APR-4
AN/APR-1 & APR-4 Radar/Comm Surveillance Receiver | N6CC
I finally found a book that had some information (Boeing B-29 Superfortress/Owners' Workshop Manual page 107). Reading through the book he noted some minor antennas and blisters and that gave me hop and sure enough he lists it on a picture of B-29 "Sister Sue." I think we can call this closed. Thanks everybody!