All the British four-engined heavies (and the Manchester before the Lancaster) were designed from the outset to be fitted with ventral turrets, but more often than not the turrets were awkward to use and were removed. In the Stirling, the FN.25 turret was prone to vibration and got filled with dirt when operating from grass. The Preston Green turret was a cupola mounting like what was originally fitted to the bombers, but it was unpowered and manually operated.
Effectiveness of Bomber Defensive Armament by Type and Location
- Thread starter Darthtabby
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Pursuivant
Airman
- 18
- Apr 29, 2011
Didn't the 8th AF publish stats on kill claims by gunner position? I can't find the information, but I believe it exists.
Cross reference that data vs. the percentage of hits from enemy fighters from each angle (meaning angle from which fighters attacked) and you get a very rough estimate of just how effective each gun position was - at least for the US heavies operating in the ETO.
I recall seeing stats which showed that tail gunners were the most effective, followed by top turret and belly gunners. On the B-17, the navigator's gun position was the least effective, to the point that it was often removed.
Going by the list of U.S. gunner aces (e.g., US Bomber Gunner Aces of WW2), where gunner positions are mentioned, tail gunners are most numerous, followed by top gunners and then ball turret gunners.
My opinion is that waist gunner positions were probably the least effective. They were single manually-turned gun positions with relatively limited arc of fire and very limited visibility which were usually making high deflection shots against targets maneuvering along multiple axes of motion (e.g., "beam attacks" from the rear flanks at the end of a "pursuit curve"). Although it wasn't well understood at the time, a bullet fired from a gun into a high speed crosswind suffers badly from "ballistic jump." While massive, high speed bullets like 0.50 BMG rounds are less vulnerable to this effect they still suffered from it. Additionally, bullets trajectories are slightly different when shooting at targets significantly above or below the shooter. Given that making precision shots on level ground at 300+ yards/meters in a high crosswind is tricky even for a well-braced shooter it must have been nearly impossible to get a good grouping while shooting from a standing position inside a vibrating bouncing aircraft flying at 200+ mph while trying to hold the gun steady against the slipstream.
Gunnery schools of the time didn't get into the ballistics required to get consistent hits and ignored factors like altitude (thinner air means less drag on the bullet and also slightly reduces gravity, it also has the illusory effect of making distant targets seem closer unless you have a frame of reference to judge the target's size), temperature (colder air increases drag), and the required angle of "holdover" required to hit much higher or lower targets.
Another factor is overall visibility from the gun position. It takes a gunner a moment to "acquire" a target and to judge its distance, speed, and vector before firing. For high deflection shots (i.e., a target flying along very different vectors from the gunner's aircraft) the ability to "track" the target prior to opening fire is vital. That corresponds to powered turrets with wide fields of fire like the top and belly turrets on the B-17 and B-24.
At night, visibility is crucial. Against the blacked out terrain of WW2 Europe, it was very difficult, if not impossible, for gunners to detect aircraft below them. In particular, it's very difficult to track dark objects moving quickly against a dark background, making high angle deflection shots almost impossible. Again, that favors gun positions with wide angles of fire, but with the added requirement that the gunner had to have something which would silhouette the target - like a burning city or light reflected from overcast or undercast clouds. It's no surprise that the Luftwaffe preferred to attack night bombers from below. It's also no surprise that the tail gunner was the person best positioned to see enemy fighters sneaking up from below and behind, since he would have a longer period of time to track a potential target.
Cross reference that data vs. the percentage of hits from enemy fighters from each angle (meaning angle from which fighters attacked) and you get a very rough estimate of just how effective each gun position was - at least for the US heavies operating in the ETO.
I recall seeing stats which showed that tail gunners were the most effective, followed by top turret and belly gunners. On the B-17, the navigator's gun position was the least effective, to the point that it was often removed.
Going by the list of U.S. gunner aces (e.g., US Bomber Gunner Aces of WW2), where gunner positions are mentioned, tail gunners are most numerous, followed by top gunners and then ball turret gunners.
My opinion is that waist gunner positions were probably the least effective. They were single manually-turned gun positions with relatively limited arc of fire and very limited visibility which were usually making high deflection shots against targets maneuvering along multiple axes of motion (e.g., "beam attacks" from the rear flanks at the end of a "pursuit curve"). Although it wasn't well understood at the time, a bullet fired from a gun into a high speed crosswind suffers badly from "ballistic jump." While massive, high speed bullets like 0.50 BMG rounds are less vulnerable to this effect they still suffered from it. Additionally, bullets trajectories are slightly different when shooting at targets significantly above or below the shooter. Given that making precision shots on level ground at 300+ yards/meters in a high crosswind is tricky even for a well-braced shooter it must have been nearly impossible to get a good grouping while shooting from a standing position inside a vibrating bouncing aircraft flying at 200+ mph while trying to hold the gun steady against the slipstream.
Gunnery schools of the time didn't get into the ballistics required to get consistent hits and ignored factors like altitude (thinner air means less drag on the bullet and also slightly reduces gravity, it also has the illusory effect of making distant targets seem closer unless you have a frame of reference to judge the target's size), temperature (colder air increases drag), and the required angle of "holdover" required to hit much higher or lower targets.
Another factor is overall visibility from the gun position. It takes a gunner a moment to "acquire" a target and to judge its distance, speed, and vector before firing. For high deflection shots (i.e., a target flying along very different vectors from the gunner's aircraft) the ability to "track" the target prior to opening fire is vital. That corresponds to powered turrets with wide fields of fire like the top and belly turrets on the B-17 and B-24.
At night, visibility is crucial. Against the blacked out terrain of WW2 Europe, it was very difficult, if not impossible, for gunners to detect aircraft below them. In particular, it's very difficult to track dark objects moving quickly against a dark background, making high angle deflection shots almost impossible. Again, that favors gun positions with wide angles of fire, but with the added requirement that the gunner had to have something which would silhouette the target - like a burning city or light reflected from overcast or undercast clouds. It's no surprise that the Luftwaffe preferred to attack night bombers from below. It's also no surprise that the tail gunner was the person best positioned to see enemy fighters sneaking up from below and behind, since he would have a longer period of time to track a potential target.
33k in the air
Staff Sergeant
- 1,219
- Jan 31, 2021
Wouldn't that be the gun in the top of the radio room? The visibility there was highly limited and attacks that it could target were rare.
Reluctant Poster
Staff Sergeant
- 1,381
- Dec 6, 2006
The navigator and bombardier were in the nose. The bombardier or more often "toggler" manned the chin turret (if fitted) while the navigator manned the handheld cheek guns. The cheek guns were removed from production but later reinstated as they were good for morale. Late production B17 deleted the wireless operators gun as it was completely useless. As someone mentioned the wait's guns were not very accurate (and were know to sometimes damage the B17s own tail plane). The second waist gunner was deleted late in the war which also helped C of G problems
