Operation Pinball Frangible Bullets

Operation "Pinball"

The main use of the P-63 in American USAAF service was the unusual one of a manned flying target for gunnery practice. The aircraft was generally painted bright orange to increase its visibility. All armament and the regular armor was removed from these RP-63 aircraft, and over a ton of armored sheet metal was applied to the aircraft. This was fitted with sensors that would detect hits form other aircraft and also from aerial gunners of bombers, these hits were signaled by illuminating a light in the propeller hub where the cannon would have been. This earned the aircraft the unofficial nickname of Pinball. Special frangible rounds made of a lead/bakelite combination were developed that would disintegrate upon impact. These were known as the "Cartridge, Caliber .30, Frangible, Ball, M22." Ivan L. Hickman, a veteran Pinball pilot, eventually authored Operation Pinball, the most authoritative book on the series, published in 1990 by Motorbooks.

The best way to train a pilot is to have him fly a real airplane until he is proficient - right? So why not train aerial gunners by letting them actually shoot at real aeroplanes? This was the concept behind one of the US Army Air Forces most unusual training programs in World War Two, often referred to as Operation Pinball.

The organised training of aerial gunners, those who would man the defensive turrets and guns of the medium and heavy bombers of the USAAF, did not begin to until June 1941, when the first flexible gunnery school was established at Las Vagas, Nev. The site featured good flying weather plus lots of uninhabited land over which practice gunnery could be conducted. Over the next two and a half years, aerial gunnery schools were also opened in Arizona at Kingman and Yuma, Texas at Harlingen and Laredo, and in Florida at Tyndall Field near Panama City and an instructors school at Buckingham Field, near Ft Meyers. At all schools, most of the early gunnery training was conducted using such make shift devices as shotguns mounted on the back of moving platforms, or more sophisticated gun camera and projection screen trainers, such as the Jam Handy and Waller trainers. Some of the best and most realistic training came using gun cameras to "fire" at attacking fighters from the actual gun positions of medium and heavy bombers - but scoring and correction of the student's performance had to wait for the film to be processed after the flight.

One man responsible for the gunnery training aids used at Harlingen in 1942 was Maj. Cameron Fairchild, and he is credited with the idea of developing a non-lethal bullet that could be fired at real fighters without actually shooting it down. Initially, the idea was that the bullets could be made of glass, that would break apart and splinter upon hitting anything solid. To research ways to make a "frangible" bullet, Fairchild enlisted the help of two professors from Duke University, Paul Gross and Marcus Hobbs.

In the fall of 1942, Fairchild presented his idea to the National Defense Research Committee (NDRC) where the propsal ran straight into a brick wall - the Army's Ordnance Department, responsible for the development of all weapons and ammunition. Ordnance argued that any bullet that was truly frangible would not have the same ballistic characteristics as real ammunition and would fire from normal machine guns. They also worried that if such a bullet were fired at a target aircraft, the plane and its pilot would need special armor and other protection. The results were that the NDRC allowed research to continue but with limited funding and urgency. With the support of the Bakelite Corporation and Duke University, professors Gross and Hobbs finally developed a .30 caliber bullet made of lead and bakelite (an early plastic) which could be fired from a slightly modified machine gun. The bullet did not damage heavy aluminum panels at ranges as close as 30-40 feet. By early 1944, a workable frangible bullet was ready for production under designation T-44.

With the ammunition and gun problem solved, focus now turned to finding a suitable target aircraft. Initial tests had been performed against a Douglas A-20 twin-engine attack bomber, which had been fitted with aluminium armor in its nose and other exposed areas. However, a single-engine fighter, preferably with a liquid-cooled engine engine, would more closely resemble and simulate the German Messerschmitt 109 fighter, so often encountered by American Gunners over Europe. The only high-performance modern American Fighter that was not in demand for combat use by US Forces was Bell's P-63 Kingcobra, most of which were being provided to the Soviet Union under Lend-Lease. In August 1944, Bell modifed five P-63A airframes, removing all armament, replacing much of the forward alumiinum panels with thicker, armoured panels and installing armored glass in the wind screen and side windows. In addition, over 100 microphones were installed behind the armored panels and rigged to indicate hits on a counter in the cockpit. A red light replaced the muzzle of the 37mm cannon in the propeller spinner and was to flash each time the plane was hit by a frangible bullet.

Officially designated RP-63As (restricted from combat use), the five prototypes quickly became know as "Pinballs" and one had this name painted boldly on its nose. After a few weight and balance problems had been worked out, a further 95 RP-63As were ordered, followed by 200 RP-63Cs in early 1945. With the first deliveries of mass produced frangible ammunition and Pinball aircraft, training finally got going under way in early 1945, and the AAF staged a public demonstration of the new program in March of that year. By April 1945, frangible bullet training using Pinball planes was underway at all seven flexible gunnery schools. Several problems marred the training, some as had been predicted by the Ordnance Department. Gun sights had to be recalirated for the lesser velocity and different trajectory of the frangible bullets, and the lead and plastic bullets caused the guns to jam more than usual. Worse for the pilots of the Pinballs were the occasional real round of ammunition that got mixed in with the practice rounds! One pilot returned with his 38mm armoured wind screen cracked, and it was agreed that no plastic bullet could do that.

But Frangible bullets themselves did occasionally down a target plane, when the gunners continued firing as the Pinballs peeled off to start another mock attack. This allowed fragments of the bullets to hit the oil and coolant radiators mounted in the wing roots, quickly causing the Pinball's engine to overheat. Thankfully, most such "kills" ended with a safe gear down landing the dessert. To better protect the target plane and pilot, the last version of the Pinball, the RP-63G, had armor extended further back to protect the engine cooling intakes - the total weight of armor reaching 2,164 pounds. In addition, more lights were added on the fuselage and wings to better indicate hits to the gunners. Only 32 of these ultimate Pinballs had been delivered when production was cancelled at the end of the war.

With future fighters and bombers both jet powered and muc faster, conventional aerial gunnery was to become obsolete. The Boeing B-29's gun turrets were already remotely controlled, except for the tail gun, with complex electro-mechanical computers to aid in their aiming. Thus, the Pinballs and frangible bullet program were transferred from the AAF's Training Command to the new Strategic Air Command where they continued to help train B-29 gunners. By 1948, however, even SAC had abandoned the program. The surviving Pinball aircraft were redesignated as QF-63's just in time for most to be mothballed or scrapped.

If the franible bullet program had been developed earlier, woult it and Operation Pinball have American bomber crews over Europe in 1944? Many involved in the Pinball program think so, but with the end of the war came the end of the long and heroic tradition of aerial gunnery, so we will never know for sure. One can only imagine that the Pinball P-63 pilots breathed a collective sign of relief.

Article by: Col. Randy Wilson.