B-17 GUN
- Thread starter Johnbr
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High Quality video on the Sperry Ball Turret:
View: https://youtu.be/MUUF_LPeTfs?si=aq0RgkwDbFTLmJD9
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The different gun installations that were trialed on the USAAF's heavy bombers are of some interest to me. The .50 caliber AN/M2 was the standard for everything but I'm wonder what else was tested. I know a handful of B-17s were trialed with 20mm Hispano cannons in the nose or tail. The nose mounting was found unsuitable due to heavy recoil, but the tail mount seems like it may have been more successful.
I've heard some claims of other guns up to 40mm in caliber being tested over the years, including on the YB-40 escorts, but some of it sounds unlikely. The 40mm Bofors would be too heavy and too much recoil for any realistic non-fixed mounting. Yet it seems the 40mm (2-pdr) Vickers 'S' gun was used in a nose mounting on at least one RAF Coastal Command Fortress, as mentioned in another thread here.
https://www.secretprojects.co.uk/threads/boeing-yb-40-variations.1258/
I've heard some claims of other guns up to 40mm in caliber being tested over the years, including on the YB-40 escorts, but some of it sounds unlikely. The 40mm Bofors would be too heavy and too much recoil for any realistic non-fixed mounting. Yet it seems the 40mm (2-pdr) Vickers 'S' gun was used in a nose mounting on at least one RAF Coastal Command Fortress, as mentioned in another thread here.
https://www.secretprojects.co.uk/threads/boeing-yb-40-variations.1258/
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Considering that B-29s came with a 2x .50cal 1x 20mm mount in the tail, I'd say that it was successful.
Just maybe not for B-17s.
I have Jablonski's book on the Flying Fortress...I seem to remember a photo of a huge aft gun...the caption read it as a prank.
After my parents bought a new rug, I got the core tube and put it atop my treehouse to make it look like a turret.
Something similar here?
After my parents bought a new rug, I got the core tube and put it atop my treehouse to make it look like a turret.
Something similar here?
All -
If memory serves....the YB-29 prototype was configured at one point, with two blister- mounted 20mm cannons; positioned on Lt and Rt side of fuselage below the cockpit.
With regards,
357Mag
I think this is the one you were referring to. An early B-29 modified with manned turrets and two single chin mounts. No 20mm. All 0.5"
Project S68 – The Manned Turret B-29 Superfortress
Project S68 was an effort to evaluate the operation of manned turrets on the Boeing B-29 Superfortress in the event of difficulties with the General Electric remote turret system. A single airframe…
inchhighguy.wordpress.com
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The 40mm Vickers S together with a predictor sight was fitted in a dorsal turret in the Wellington for trials, as a planned installation for the Vickers Type 414, so a turret for that is certainly possible.
Ewen -I think this is the one you were referring to. An early B-29 modified with manned turrets and two single chin mounts. No 20mm. All 0.5"
Project S68 – The Manned Turret B-29 Superfortress
Project S68 was an effort to evaluate the operation of manned turrets on the Boeing B-29 Superfortress in the event of difficulties with the General Electric remote turret system. A single airframe…
Howdy !
Looks about right. I saw an in-flight pic of the plane in some obscure magazine, while I was sitting in my dentist office when I was 12.... 58 yr ago.
With regards,
357Mag
Hi Ewen,
Thanks a lot for the link!
The chin mounts are really odd indeed - I'd imagine they must have had a lot of drag.
The other mounts were more conventional, but I would think they there were not pressure tight. The dorsal turret certainly looks just like the B-17's, so the implication is that when equipped with these turrets, the B-29 could not be pressurized.
As far as I know, the General Electric remote control system wasn't actually all that good. Over on ww2aircraft.net, a while ago some documents were posted that showed that the USAAF found the alignment of sights to the guns difficult to establish with the required precision, as any twisting of the fuselage would mis-align them relative to each other. Additionally, they were critical of the approach of directly tracking the apparent position of the enemy aircraft purely manually, which was difficult to do with the smoothness required by the analog computer to calculate valid firing solutions. The report argued that the more conventional approach of controlling the tracking rates (azimuth and elevation speeds) was superior in that regard.
With regard to pressurization, I don't actually know how important this turned out as my impression is that when enemy aircraft could be expected to be encountered, the aircraft was depressurized anyway to avoid the risk of explosive decompression. At least later in the war, the inbound flight was made at low altitude anyway, to reduce the strain of the engines which were less taxed by climbing later in the flight when a lot of fuel had already been consumed and the aircraft was lighter. Without looking it up, it might also be that cruise climb or step climb techniques were employed. Not sure about the return flight, but letting down once outside the range of enemy fighter would probably have been possible for a non-pressurized B-29 variant without undue impact on its operational capabilities.
By the way, the B-29 documents posted on ww2aircraft.net also showed that the elimination of (almost) the entire armament was an option considered even before the B-29's combat experience showed that the bomber's heavy weight made the ambitious high-altitude long-range attack profile the USAAF used very demanding. Accordingly, General Curtiss LeMay probably could rely on a very solid and professional assessment of the pros and cons of the armament removal when he took his famous decision.
Regards,
Henning (HoHun)
I think this is the one you were referring to. An early B-29 modified with manned turrets and two single chin mounts. No 20mm. All 0.5"
Project S68 – The Manned Turret B-29 Superfortress
Project S68 was an effort to evaluate the operation of manned turrets on the Boeing B-29 Superfortress in the event of difficulties with the General Electric remote turret system. A single airframe…
Thanks a lot for the link!
The chin mounts are really odd indeed - I'd imagine they must have had a lot of drag.
The other mounts were more conventional, but I would think they there were not pressure tight. The dorsal turret certainly looks just like the B-17's, so the implication is that when equipped with these turrets, the B-29 could not be pressurized.
As far as I know, the General Electric remote control system wasn't actually all that good. Over on ww2aircraft.net, a while ago some documents were posted that showed that the USAAF found the alignment of sights to the guns difficult to establish with the required precision, as any twisting of the fuselage would mis-align them relative to each other. Additionally, they were critical of the approach of directly tracking the apparent position of the enemy aircraft purely manually, which was difficult to do with the smoothness required by the analog computer to calculate valid firing solutions. The report argued that the more conventional approach of controlling the tracking rates (azimuth and elevation speeds) was superior in that regard.
With regard to pressurization, I don't actually know how important this turned out as my impression is that when enemy aircraft could be expected to be encountered, the aircraft was depressurized anyway to avoid the risk of explosive decompression. At least later in the war, the inbound flight was made at low altitude anyway, to reduce the strain of the engines which were less taxed by climbing later in the flight when a lot of fuel had already been consumed and the aircraft was lighter. Without looking it up, it might also be that cruise climb or step climb techniques were employed. Not sure about the return flight, but letting down once outside the range of enemy fighter would probably have been possible for a non-pressurized B-29 variant without undue impact on its operational capabilities.
By the way, the B-29 documents posted on ww2aircraft.net also showed that the elimination of (almost) the entire armament was an option considered even before the B-29's combat experience showed that the bomber's heavy weight made the ambitious high-altitude long-range attack profile the USAAF used very demanding. Accordingly, General Curtiss LeMay probably could rely on a very solid and professional assessment of the pros and cons of the armament removal when he took his famous decision.
Regards,
Henning (HoHun)
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Another good article from that same site about the YB-29 turned into an escort gunship, similar to the YB-40 and XB-41.
https://inchhighguy.wordpress.com/2024/05/01/boeing-b-29-superfortress-gunship/
Of note is the tail guns, the biggest gun is described as being a 30mm autocannon but I can't think of any Allied design in that caliber. The other two are said to be .50 caliber Brownings, but they look like 20mm Hispanos to me. It is certainly an extreme amount of defensive firepower, but the escort gunship had proven itself to be a flawed concept.
https://inchhighguy.wordpress.com/2024/05/01/boeing-b-29-superfortress-gunship/
Of note is the tail guns, the biggest gun is described as being a 30mm autocannon but I can't think of any Allied design in that caliber. The other two are said to be .50 caliber Brownings, but they look like 20mm Hispanos to me. It is certainly an extreme amount of defensive firepower, but the escort gunship had proven itself to be a flawed concept.
Hi,
Fascinating, but not only are the sighting blisters missing, but there seem to be no other provisions for sighting at all, as far as I can tell.
The nose "turett" might have built-in sights, and possibly there's something like a periscopic sight just cut off at the bottom of the rear turret picture (though it might be something completely different), but how would all those other guns be sighted?
Somehow, this looks more like a turret test-bed aircraft than a feasible gunship to me ...
(The next step up from the 20 mm Hispano probably would be a 37 mm cannon, in the USAAF's arsenal.)
Regards,
Henning (HoHun)
Fascinating, but not only are the sighting blisters missing, but there seem to be no other provisions for sighting at all, as far as I can tell.
The nose "turett" might have built-in sights, and possibly there's something like a periscopic sight just cut off at the bottom of the rear turret picture (though it might be something completely different), but how would all those other guns be sighted?
Somehow, this looks more like a turret test-bed aircraft than a feasible gunship to me ...
(The next step up from the 20 mm Hispano probably would be a 37 mm cannon, in the USAAF's arsenal.)
Regards,
Henning (HoHun)
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