Bombers had single .50 free-flexible waist guns on each side. This one is in a B-17G.
In World War II, the US Army Air Corps, later Army Air Forces, exploded in size and importance from a small branch of Mother Army to a mighty strategic war arm of its own. Its fleet of heavy, medium and light bombers required vast quantities of trained gunners: a heavy bomber had around ten gun positions (some of which were manned by assigned job-title gunners, and some of which were an “additional duty” of other crewmen like crew chiefs and bombardiers). A medium bomber might have two turrets (dorsal and tail), flexible waist guns and guns forward under the control of the pilot or bombardier and navigator. Even a light bomber like the A-20 attack plane or the A-24 (the Army’s version of the Navy’s Douglas Dauntless) had flexible tail guns and fixed forward ones.
Making all these guns was a challenge, but making the gunners was an even bigger one. Scores of new units, thousands of planes, and hundreds of thousands of new gunners were needed. And as the war wore on, more detail was needed. Training hours increased from 150 in early 1942 to to 290 in May 1944, and the quality and depth of the instruction — and the degree to which it was standardized and specified by higher training commands, in response to demands from the field Air Forces — also increased.
An example of the kind of increase in training was the addition, in 1943, of intensive and specific training in clearing malfunctions. In summer 1942, one training day — 8 hours — was given to malfunctions, and only of the .30 machine gun (the .50 was not in plentiful enough supply for the training command to have them). 28 hours were spent on weapons, overall, to include nomenclature, functions, and operator disassembly/reassembly and maintenance. By the end of the year, two hours had been added to each block of instruction (30 weapons/10 malfunctions). By mid-1943, there were 46 hours of weapons training, of which 40 were on the .50 machine gun, and only 6 on the .30, and 20 hours of malfunction training.
The malfunction training by that point included a specific “malfunction range” where gunnery trainees had to learn to, and demonstrate their ability to, clear 7 types of Browning machine gun malfunctions:
- Failure to feed into feedway.
- Failure to extract from belt. A Browning machine gun pulls the cartridges back out of the belt, regardless of whether the cartridge is rimmed (i.e. .303 as used in the Spitfire and Hurricane Mk. I in the RAF) or rimless (as in the US .30-06).
- Failure to feed into the chamber.
- Failure to fire.
- Failure to control fire. (I.e., runaway gun).
- Failure to extract from the chamber, and:
- Failure to eject.
A trainee who’d addressed each of these on a flat range in the heat of Texas or Nevada or Florida, was better equipped to deal with any of them in the face of the enemy and in the subzero cold and thin air of the stratosphere over Germany or the steamy conditions of the South Pacific. And just having the possible burps of the extremely reliable Browning laid out so logically built the gunner’s confidence in his armaments.
The prototypes of the B-17 has four or five single .30 caliber guns.
Before he tackled malfunctions, the regulations specified what he had to know about function and maintenance. Between-flight maintenance in the USAAF was generally the province of specialist armorers, who’d remove the guns from the aircraft, clean, repair if necessary, and function-check them. The gunners were responsible for operator maintenance only, which could included cleaning and disassembly but usually meant simply preflight inspection and inflight emergency maintenance. Guns were routinely test-fired on the outbound leg of the flight, usually by the whole formation and prior to crossing the enemy coast or coming within the usual operating range of enemy interceptors. The defensive theory of the WWII bomber box relied not on the individual gun but on the interlocking fires from the aircraft in formation to complicate the attacking fighters’ plans, but each individual aircrew, and each individual gunner, had a somewhat solitary fight even amidst a large formation.
Mechanical training was designed to produce a gunner expert in the functioning of his weapon, and therefore best equipped to reduce any stoppages and get a malfunctioning gun back up and shooting ASAP. To that end, the gunner had to master these tasks — blindfolded:
- Field-strip the gun;
- Reassemble it, even if the parts had been jumbled by the instructors;
- Adjust the gun’s headspace;
- Adjust the oil buffer tube;
- Change the direction of feed (the Browning MG is easily changed for left or right feed, an advantage over most of its contemporaries).
In addition, the would-be gunner had 17 other mechanical tasks to manage — but he didn’t have to be blindfolded.
One thing that kept this training task manageable was that the US only fielded two main versions of aerial machine guns: the Browning .30 and .50 caliber aerial guns. The guns had many similarities, and were close cousins to one another and to their ground-forces versions. The air forces model generally had some weight-reduction, much lighter barrels (counting on airflow for cooling), and a much higher rate of fire for engaging the fleeting targets of aerial combat. The Brownings were gunner- and maintenance-friendly; they generally lacked small parts that were easily lost and insidious springs that would launch said parts in untoward directions, both features found on many foreign competitors.
These mechanical and range training hours and tasks mentioned above were in addition to training on aircraft recognition, turrets, and the theory of aerial gunnery. Each of those training blocs also evolved during the war.
For example, after an initial foray into complexity, with gunners learning an additive system of aircraft recognition called WEFT — Wings, Engines, Fuselage and Tail. Then the WEFT profile of the bogey was compared to the mentally stored profiles of scores of allied and enemy aircraft. Or — if no mental match was made — looked up in a book. (This is a bit like armored vehicle recognition systems that ask the guy under tank attack to count wheels. It’s too slow, even when it does work). The poor performance of this system in combat led to an overhaul of recognition training in 1943, and adoption of the Renshaw “Flash” system, developed by an Ohio State psychologist with an emphasis on instant recognition of enemy aircraft morphology (the same way a kid can unerringly tell a Challenger from a Camaro on today’s highway). However, the field air forces came up with an even simpler criterion: if the aircraft maneuvers to attack you, treat it as hostile! Between the Renshaw technique and what you might call the Mama Gump technique (“enemy is as enemy does”), recognition-training hours were cut in half, from 20 to 10.
The YB-40 had extra turrets and doubled waist guns, and carried 11,000 rounds of .50 ammo. Despite all that hardware, they only shot down two German fighters for the loss of one B-40 before the USAAF gave up on them.
Turrets were not initially part of training because, in 1941, relatively few aircraft had them, and those had them in relatively few positions. (For instance, the first B-17s had only one turret, in the nose, with a total of 5 .30-caliber guns; the late-war B-17G had four turrets and 14 guns, all .50s). The ultimate gun-bearing bomber was the XB-40, a B-17 version meant to defend formations and carry no bombs: it had from 18 to 30 .50 caliber guns mounted, but was not a success (it couldn’t keep up with the bombers after they’d dropped their loads).
As turrets became more common in the field, they spread to the training base. As well as in-aircraft training, turrets were set up on the machine gun ranges for the future gunners to train with. In 1941, the only aerial gunnery was conducted from the back seat of a North American T-6 Texan trainer, firing a flexible .30 at a towed target sleeve. In 1942, B-34s (the Army version of the Lockheed Ventura) were used at the training fields to give the gunnery trainees turret experience; starting in 1943, the gunners got hands-on in bombers, as the gunnery bases were also training bases for B-24 or B-17 crews.
Why you lead from behind. From the Gunner’s Information File. (As usual, click to embiggen)
Theory was important because, with converging targets moving at hundreds of miles an hour in three dimensions, calculating or estimating lead was critical — and sometimes, counterintuitive. For example, a gunner hoping to engage an enemy fighter who began with a beam attack and then curved in to a 3/4 rear attack had to lead the enemy plane behind its present position. The earliest trainees were taught to always lead ahead of the enemy aircraft based on an estimate of its speed, and they were not successful in countering this kind of attack until the theoretical training matured enough to handle it.
No other nation — not even the usually fussy Germans — had as specific a training schedule, or produced as effective aerial gunners as the US did in World War II. After the war, the art and science of aerial gunnery fell into disuse, as the Air Force in the nuclear age was more committed to Douhet’s adage that “the bomber will always get through.” The last plane the Air Force sent to combat with defensive guns was the B-52, in Operation Linebacker in 1972, and a dozen or so years after that the training of aerial gunners was finally over.
Resources & References
The principal source of this report is the declassified Army Air Forces Historical Study No. 31, Flexible Gunnery Training in the AAF, from the Air Force Historical Research Archives. This 1945 study, originally Secret, was downgraded to Restricted – Security Information (a now deprecated classification) in 1953, and declassified completely at some time after that (the labeling on the document is obscured). There are no redactions. A .pdf from a microfilm is available here: http://www.afhra.af.mil/shared/media/document/AFD-090602-068.pdf The illustrations are illegible due to the usual issues with microfilm. All the numbered AAF Historical Studies can be found here: http://www.afhra.af.mil/studies/numberedusafhistoricalstudies.asp
Snow, Crocker, and Gleason, Pam. Log Book: A Pilot’s Life. New York: Brassey’s, 1997. In this very wide-ranging memoir, Snow discusses mid-war changes in gunnery theory and training from the point of view of a B-17 and B-29 group commander who had the ear of the highest levels of command.
Finally, there’s an entertaining movie called Aerial Gunner that details the WWII training of these guys, framed in a classic Hollywood love triangle. Great cinematic art it might not be, but it’s entertaining, and it’s extra entertaining if you’re interested in guns and gunnery training as it existed mid-20th Century. Best of all, the film, produced and directed by William Pine, appears to have passed into the public domain, so it’s on all those el-cheapo 50 Ear Movies DVD compilations, and it’s even available from the Internet Archive for download or streaming. You can curse us later for wasting 1:18 of your time.
There’s also another one called The Rear Gunner that shows up on some of those compilations — starring Burgess Meredith and some cat named Ronald Reagan. We haven’t seen that one. (Update. It’s a recruiting short, 20 minutes long, and you can watch it, too, at the Internet Archive. It shows BB gun and skeet training — sometimes those GI skeet guns come up for sale and they’re an inexpensive and interesting bit of history — as well as .30 and .50 MG training).
The wartime Gunners’ SOP of the 303rd Bomb Group (Hells Angels) is also available online.
And the 491st Bombardment Group put a partial Gunner’s Information File on line some years ago. Each Air Force crew position had an Information File that was a loose leaf notebook full of illustrated knowledge. The leaf from the GIF used in this post came from the 491st.