B-25 weapons thread (1 Viewer)

[MiTasol]

The 2 loop antennae are seen on some of those general-transports (check B-25 gen. Arnold or gen. Eisenhower). I do believe the second one is a back-up (double radio compass).

It is possible, considering the persons carried, that the two antennas were to allow the nav to triangulate the aircraft's position "instantly" rather than by taking one bearing then hunting for and finding a second known signal source given that the ADFs of the day required hand tuning the receivers.

 

[CATCH 22]

It is possible, considering the persons carried, that the two antennas were to allow the nav to triangulate the aircraft's position "instantly" rather than by taking one bearing then hunting for and finding a second known signal source given that the ADFs of the day required hand tuning the receivers.

Quite possible in the case with the weather-plane - the both antennae are mounted with a distance one from another.
On the general's planes they were always together, under the nose. I think I read somewhere about doubling some of the systems on those important a/c. Below is the first B-25 of gen. Arnold (the one that still flies) - compare with the photo of the weather-plane. BTW don't know the purpose of the ring-antenna on top of the nose.

 

[GrauGeist]

BTW don't know the purpose of the ring-antenna on top of the nose.

The ring or "null loop" antenna was used for direction finding.

 

[Greg Boeser]

The ring or "null loop" antenna was used for direction finding.

The Doughnut of Death.

 

[MiTasol]

The ring or "null loop" antenna was used for direction finding.

And was usually part of an earlier type DF system. Three DFs on one aircraft appears an overkill but it may well be that the ring type was more sensitive on certain frequencies.

 

[CATCH 22]

And was usually part of an earlier type DF system. Three DFs on one aircraft appears an overkill but it may well be that the ring type was more sensitive on certain frequencies.

I too think that this is an overkill. Maybe in this case the top loop antenna and one of the radio-compass DF-antennae was used for that instant location of the position, you mentioned before? The same configuration was seen on the very first B-25 s/n 40--2165 modified for company needs (transport, tests) by NAA:

Gen. Arnold's plane s/n 40-2168 was later used as a transport for other high ranking officers and then sold to the private market. The late nose-antenna was different:

 

[GrauGeist]

The "ring" antenna was extremely sensitive to weak radio signals, capable of fine adjustment to get a "fix" on the source.

Virtually all maritime/scout aircraft in the 1930's were equipped with the null loop direction finding equipment as well civil airliners, especially long distance types.

 

[MiTasol]

A new site - to me anyway.

B-25 History Project

B-25 Mitchell bomber history

b-25history.org

 

[CATCH 22]

A new site - to me anyway.

B-25 History Project

B-25 Mitchell bomber history

b-25history.org

Since 2014. It is pretty good. I think they add some new details from time to time so it's worth checking the site periodically. Some very good photos from the "biography" of each B-25 they describe.

 

[CATCH 22]

Back to more weapons and weapon systems or weapon-related details.
I think I found a photo I haven't seen before that explains some earlier confusions and wrong statements.
Before that a drawing and a picture many of us have probably seen:
1, Drawing from a book showing a strange, "flattened" top turret (don't remember the exact source though):

2. A photo of the same turret as above - I believe the drawing was made using the photo below:

It was said this is a B-25H turret with a new form. I've seen on some occasions modellers to argue that it is the real turret for the late models (H and J) - this is not true.
3. And here's the new (for me) photo from the Boeing-archive:

It is a NAA-suggestion only. Didn't go in mass production. "Mustangs" in the background prove that this is the NAA-factory in Inglewood, California, manufacturing B-25H but not B-25J. Note the transparent gun slot shields.
And one more photo: on restored B-25 wee see sometimes different turrets like the one below:

IMHO this is not an original B-25 turret.

Cheers!

 

[B25Nut]

The last one is a Martin turret that has been adapted to mamy B-25 restorations. I think the confusion about the low drag version was started by the excellent book by Ed Schnepf, North American B-25. It used the illustration and photo of the low drag turrent and implied it was the standard top turret. My guess it that NAA had one made and tested it on the NA-98X Super Strafer, although I've never seen a photo of the low drag turret on that aircraft. Your photo at the B-25 factory is probably a closeup of the NA-98X taken before it was determined to not be worth the extra effort

 

[CATCH 22]

The last one is a Martin turret that has been adapted to mamy B-25 restorations. I think the confusion about the low drag version was started by the excellent book by Ed Schnepf, North American B-25. It used the illustration and photo of the low drag turrent and implied it was the standard top turret. My guess it that NAA had one made and tested it on the NA-98X Super Strafer, although I've never seen a photo of the low drag turret on that aircraft. Your photo at the B-25 factory is probably a closeup of the NA-98X taken before it was determined to not be worth the extra effort

It's not in the "Blue book" - checked it immediately. Must be a different one. My problem is that I do not remember anymore where did I see something many years ago. I must check all books I have (need a couple of days maybe) but it's not the one you say.
P.S. I found the photo with the low drag turret in Bert Kinzey's book, page 68, not saying this was a NAA experiment only.

I haven't seen a photo of the "Super Strafer" with the low drag turret, but you might be right, that they used this particular a/c for the photos.
There is a famous factory illustration of a B-25H with strange cowlings and intakes, mixing reality with the test-plane (NA-98X) and the turret looks slightly lower than usual. Could be part of the same development:

 

[Thumpalumpacus]

I found and watched this vid last night, specific to the 345th BG but more generalist in its approach to weaponry. Interesting for those into the unit history.


View: https://www.youtube.com/watch?v=gchVRNTUwcs

 

[Maty12]

It's not in the "Blue book" - checked it immediately. Must be a different one. My problem is that I do not remember anymore where did I see something many years ago. I must check all books I have (need a couple of days maybe) but it's not the one you say.
P.S. I found the photo with the low drag turret in Bert Kinzey's book, page 68, not saying this was a NAA experiment only.

I haven't seen a photo of the "Super Strafer" with the low drag turret, but you might be right, that they used this particular a/c for the photos.
There is a famous factory illustration of a B-25H with strange cowlings and intakes, mixing reality with the test-plane (NA-98X) and the turret looks slightly lower than usual. Could be part of the same development:

Yves,

B-25History.org states that the photo of the top turret is actually of the NA-98X, based on the engine visible in the corner. I cannot confirm or deny this as engines aren't my forte. That NAA drawing seems a pretty good match for the NA-98X as built, minus the exhaust stacks. Old Machine Press and B-25History.org both have a few photos of the plane. On the side view it doesn't look like the low drag turret to me, but it could be that the low-drag turret was only fitted for part of the NA-98X's life.

-Maty

 

[CATCH 22]

Yves,

B-25History.org states that the photo of the top turret is actually of the NA-98X, based on the engine visible in the corner. I cannot confirm or deny this as engines aren't my forte. That NAA drawing seems a pretty good match for the NA-98X as built, minus the exhaust stacks. Old Machine Press and B-25History.org both have a few photos of the plane. On the side view it doesn't look like the low drag turret to me, but it could be that the low-drag turret was only fitted for part of the NA-98X's life.

-Maty

Thanks, Matty! Great addition, telling me that I might have copied the photo from the same site, but I really do not remember this explanation about the engine.
As mentioned in my previous post my copy could be from Kinzey's book though. But the new photo I posted was actually the best for now, showing the flat NAA turret.
B-25History.org shows 3 photos only (I have them), the other site, 1 more (engine, propeller). I have a few more of the whole a/c NA-98X but all are with the standard turret. Would be nice to had it tested with the flat one. Maybe NAA decided not to manufacture the new turret at all?
But I believe this is the answer for now: the flat NAA-turret was part of project NA-98X.
Cheers!

 

[Maty12]

Thanks, Matty! Great addition, telling me that I might have copied the photo from the same site, but I really do not remember this explanation about the engine.
As mentioned in my previous post my copy could be from Kinzey's book though. But the new photo I posted was actually the best for now, showing the flat NAA turret.
B-25History.org shows 3 photos only (I have them), the other site, 1 more (engine, propeller). I have a few more of the whole a/c NA-98X but all are with the standard turret. Would be nice to had it tested with the flat one. Maybe NAA decided not to manufacture the new turret at all?
But I believe this is the answer for now: the flat NAA-turret was part of project NA-98X.
Cheers!

Glad to help. I had never seen the photo you posted before and agree it's a great one!

 

[cvairwerks]

Something to remember about flight test mules....modifications come and go, and don't always stay on aircraft. One of our test F-16's, over it's life, had more than 2000 different mods on it. It looked like swiss cheese, with all the patches, cover plates and reinforcements and repairs on it. That aircraft is now preserved in a museum in DFW.

 

[CATCH 22]

Something to remember about flight test mules....modifications come and go, and don't always stay on aircraft. One of our test F-16's, over it's life, had more than 2000 different mods on it. It looked like swiss cheese, with all the patches, cover plates and reinforcements and repairs on it. That aircraft is now preserved in a museum in DFW.

In the case with NA-98X it was quite the opposite. They couldn't test-fly it more than dozen times AFAIR, before the plane crashed due to human error. The a/c just received new engines but the old frame of a B-25H-5 remained untouched. Limitations have been added to speed and overloading the frame in flight. The new streamlined turret is just one detail they might have prepared for the future mass-production but the test plane itself was not heavily modified. They even tested it with the canon still in place, a detail that always makes me wonder "Why?"

 

[GrauGeist]

Ok guys, I have a question regarding the "low drag" turret.

Was this an attempt to enhance the B-25's top speed, or was it an attempt to enhance accuracy facing foreward to add to the guns-on for strafing?

Or was there a buffeting issue, like the P-61's dorsal turret, that was trying to be addressed?