Oshkosh P-51 Accident 2007.
Gerald Beck, 58, of Wahpeton, N.D., was killed and Casey Odegaard, 24, of Kindred, N.D., suffered only minor injuries in the fiery crash. Both airplanes were landing on Runway 36L at Oshkosh Wittman Regional Airport [MAP/SAT] when Beck’s P-51A flipped over and caught fire after it hit Odegaard’s P-51D from behind Friday afternoon, July 27, 2007.
The North American Aviation P-51 Mustang was an American long-range single-seat fighter aircraft that entered service with Allied air forces in the middle years of World War II. The P-51 became one of the conflict’s most successful and recognizable aircraft.
The P-51 flew most of its wartime missions as a bomber escort in raids over Germany, helping ensure Allied air superiority from early 1944. It also saw service against the Japanese in the Pacific War. The Mustang began the Korean War as the United Nations’ main fighter but was supplanted as a fighter by jets early in the conflict, being relegated to a ground attack role. Nevertheless, it remained in service with some air forces until the early 1980s.
As well as being economical to produce, the Mustang was a well-made and rugged aircraft. The definitive version of the single-seat fighter was powered by the Packard V-1650-3, a two-stage two-speed supercharged 12-cylinder Packard-built version of the legendary Rolls-Royce Merlin engine, and armed with six of the aircraft version of the .50 caliber (12.7 mm) Browning machine guns.
After World War II and the Korean conflict, many Mustangs were converted for civilian use, especially air racing. The P-51 is a powerful and impressive aircraft at air shows.
In 1939, shortly after World War II began, the British government established a purchasing commission in the United States, headed by Sir Henry Self. Along with Sir Wilfrid Freeman, who as the “Air Member for Development and Production” was given overall responsibility for RAF production and research and development in 1938, Self had sat on the (British) Air Council Sub-committee on Supply (or “Supply Committee”). One of Self’s many tasks was to organize the manufacture of American fighter aircraft for the RAF. At the time, the choice was very limited. None of the US aircraft already flying met European standards; only the Curtiss P-40 Tomahawk came close. The Curtiss plant was running at capacity, so even that aircraft was in short supply.
North American Aviation (NAA) was already supplying their Harvard trainer to the RAF but were otherwise underutilized. NAA President “Dutch” Kindelberger approached Self to sell a new medium bomber, the B-25 Mitchell. Instead, Self asked if NAA could manufacture the Tomahawk under licence from Curtiss.
Kindelberger replied that NAA could have a better aircraft with the same engine in the air in less time than it would take to set up a production line for the P-40. As executive head of the British Ministry of Aircraft Production (MAP), Freeman ordered 320 aircraft in March 1940. On 26 June 1940, MAP awarded a contract to Packard to build modified versions of the Rolls-Royce Merlin engines under licence; in September, MAP increased the first production order by 300.
The result of the MAP order was the NA-73X project (from March 1940). The design followed the best conventional practice of the era, but included two new features. One was a new NACA-designed laminar flow wing, which was associated with very low drag at high speeds. Another was the use of a new radiator design that used the heated air exiting the radiator as a form of jet thrust in what is referred to as the “Meredith Effect”. Because North American lacked a suitable wind tunnel, it was forced to use Curtiss’ facility. This led to some controversy over whether the Mustang’s aerodynamics were developed by North American’s engineer Edgar Schmued or by Curtiss, although historians and researchers dismiss the allegation of stolen technology; such claims are likely moot, in any event, as North American had purchased Curtiss’ complete set of P-40 and XP-46 wind tunnel data and flight test reports for $56,000.
The United States Army Air Corps could block any sales it considered interesting, and this appeared to be the case for the NA-73. An arrangement was eventually reached where the RAF would get its aircraft, in exchange for NA providing two examples cost-free to the USAAC.
The prototype NA-73X was rolled out just 117 days after the order was placed, and first flew on 26 October 1940, just 178 days after the order had been placed — an incredibly short gestation period. In general, the prototype handled well and the internal arrangement allowed for an impressive fuel load. It was armed with four .50 M2 Browning (12.7 mm) guns and two .30 Browning (7.62 mm) guns. In comparison, the British Spitfire Vb carried two 20 mm cannon and four .303 machine guns.
It was quickly evident that performance, although exceptional up to 15,000 feet, was inadequate at higher altitudes. This deficiency was due largely to the mechanically supercharged Allison V-1710 engine, which lacked power at higher altitudes. Prior to the Mustang project, the USAAC had Allison concentrate primarily on turbochargers in concert with General Electric; these proved to be exceptional in the P-38 Lightning and other high-altitude aircraft. Most of the other uses for the Allison were for low-altitude designs, where a simple supercharger would suffice. The turbocharger proved impractical for fitting into the Mustang, and it was forced to use the inadequate superchargers available. Still, the Mustang’s advanced aerodynamics showed to advantage, as the Mustang I was about 30 mph faster than contemporary Curtiss P-40 fighters using the same Allison powerplant. The Mustang I was 30 mph faster than the Spitfire Mk VC at 5,000 feet and 35 mph faster at 15,000 ft, despite the British plane’s more powerful engine.
The first production contract was awarded by the British for 320 NA-73 fighters named Mustang I by the British. Two aircraft of this lot delivered to the USAAF were designated XP-51. A second British contract called for 300 more (NA-83) Mustang I fighters. In September 1940, 150 aircraft designated NA-91 by North American were ordered under the Lend/Lease program. These were designated by the USAAF as P-51 and initially named the “Apache” although this designation was soon dropped and the RAF name, “Mustang,” adopted instead. The British designated this model as Mustang IA. They were equipped with four long-barrelled 20 mm Hispano Mk II cannon instead of machine guns.
A number of aircraft from this lot were fitted out by the USAAF as photo reconnaissance aircraft and designated F-6A. The British would fit a number of Mustang Is with similar equipment. Also, two aircraft of this lot were fitted with the Packard built Merlin engine and were designated by North American as model NA-101 and by the USAAF initially as the XP-78, but redesignated XP-51B.
About 20 of the Mustang Mk I were delivered to the RAF and made their combat debut on 10 May 1942. With their long range and excellent low-level performance, they were employed effectively for tactical reconnaissance and ground-attack duties over the English Channel, but were thought to be of l
imited value as fighters due to their poor performance above 15,000 feet.
The Mustang Mk IA was identical to the Mustang Mk I except that the machine guns were removed and replaced with four wing mounted 20 mm cannons.
At the same time, the USAAC was becoming more interested in ground attack aircraft and had a new version ordered as the A-36 Apache, which included six .50 M2 Browning machine guns, dive brakes and the ability to carry two 500 pound (230 kg) bombs.
In early 1942, the USAAF ordered 500 aircraft modified as dive bombers that were designated A-36A (NA-97). This model became the first USAAF Mustang to see combat. One aircraft was passed to the British who gave it the name Mustang I (Dive Bomber).
P-51B and P-51C (High Altitude Performance Improves)
In April 1942, the RAF’s Air Fighter Development Unit (AFDU) tested the Mustang at higher altitudes and found its performance inadequate, but the commanding officer was so impressed with its maneuverability and low-altitude speeds that he invited Ronnie Harker from Rolls Royce’s Flight Test establishment to fly it. Rolls-Royce engineers rapidly realized that equipping the Mustang with a Merlin 61 would substantially improve performance and started converting five aircraft as the Mustang X. Ministry official Sir W.R. Freeman lobbied vociferously for Merlin-powered Mustangs, insisting two of the five experimental Mustang Xs be handed over to Carl Spaatz for trials and evaluation by the US 8th Air Force in Britain.
The high-altitude performance improvement was astonishing: the Mustang X AM208 reached 433 mph at 22,000 ft and AL975 tested at an absolute ceiling of 40,600 ft.After sustained lobbying at the highest level, American production of a North American-designed Mustang, with the Packard Merlin V-1650 engine replacing the Allison, was started in early 1943. The pairing of the P-51 airframe and Merlin engine was designated P-51B or P-51C (B (NA-102) being manufactured at Inglewood, California, and C (NA-103) at a new plant in Dallas, Texas, in operation by summer 1943). The RAF named these models Mustang III. In performance tests, the P-51B reached 441 mph/709.7 km/h at 25,000 ft (7.600 m) and the subsequent extended range made possible by the use of drop tanks enabled the Merlin-powered Mustang to be introduced as a bomber escort.
P-51Bs and Cs started to arrive in England in August and October 1943. The P-51B/C versions were sent to 15 fighter groups that were part of the 8th and 9th Air Forces in England, and the 12th and 15th in Italy (the southern part of Italy was under Allied control by late 1943). Other deployments included the China Burma India Theater (CBI).
Allied strategists quickly exploited the long-range fighter as a bomber escort. It was largely due to the P-51 that daylight bombing raids deep into German territory became possible without prohibitive bomber losses in late 1943.
A number of the P-51B and P-51C aircraft were fitted for photo reconnaissance and designated F-6C.
P-51D and P-51K (Better Rear View)
One of the few remaining complaints with the Merlin-powered aircraft was a poor rearward view. This was a common problem in most fighter designs of the era, which had only been recognized by the British after the Battle of Britain proved the value of an all-around view. In order to improve the view from the Mustang at least partially, the British had field-modified some Mustangs with fishbowl-shaped canopies called “Malcolm Hoods.” Eventually all Mk IIIs, along with some American P-51B/Cs, were equipped with Malcolm Hoods.
A better solution to the problem was the “teardrop” or “bubble” canopy. Originally developed as part of the Miles M.20 project, these newer canopies were in the process of being adapted to most British designs, eventually appearing on late-model Spitfires, Typhoons and Tempests. North American adapted several NA-106 prototypes with a bubble canopy, cutting away the decking behind the cockpit to allow looking directly to the rear. This led to the production P-51D (NA-109), considered the definitive Mustang.
A common misconception is that the cutting down of the rear fuselage to mount the bubble canopy reduced stability that required the addition of a dorsal fin to the forward base of the vertical tail. Actually, both earlier Bs and Cs and subsequent D/K models also experienced low speed handling problems that could result in an involuntary “snap-roll” under certain conditions of air speed, angle of attack, gross weight and center of gravity. Several crash reports tell of P-51Bs and Cs crashing because horizontal stabilizers were torn off during maneuvering. One report stated:
While some existing aircraft do not have the dorsal extension fitted, many were equipped at some point in their service or refurbishment with a taller tail, which provided a similar increase in yaw stability. Also, civilian-owned examples often have newer, lighter radios, an absence of external munitions and drop tanks, removed guns and armor plate and an empty or removed fuselage tank
— reducing the need for the dorsal fin.
Among other modifications, armament was increased with the addition of another two M2 machine guns, bringing the total to six. The inner pair of machine guns had 400 rounds each, and the others had 270 rounds, for a total of 1,880. In previous P-51s, the M2s were mounted at angles that led to frequent complaints of jamming during combat maneuvers. The new arrangement allowed the M2s to be mounted in a more standard manner that remedied most of the jamming problems. The .50 caliber Browning machine guns, although not firing an explosive projectile, had excellent ballistics and proved adequate against the Fw 190 and Bf 109 fighters that were the main USAAF opponents at the time. Later models had under-wing rocket pylons added to carry up to ten rockets per plane.
The P-51D became the most widely produced variant of the Mustang. A Dallas-built version of the P-51D, designated the P-51K, was equipped with an Aeroproducts propeller in place of the Hamilton Standard propeller, as well as a larger, differently configured canopy and other minor alterations (the vent panel was different). The hollow-bladed Aeroproducts propeller was unreliable with dangerous vibrations at full throttle due to manufacturing problems and was eventually replaced by the Hamilton Standard. The photo reconnaissance versions of the P-51D and P-51K were designated F-6D and F-6K respectively. The RAF assigned the name Mustang IV to the D model and Mustang IVA to K models.
The P-51D/K started arriving in Europe in mid-1944 and quickly became the primary USAAF fighter in the theater. It was produced in larger numbers than any other Mustang variant. Nevertheless, by the end of the war, roughly half of all operational Mustangs were still B or C models.
During 1945–48, P-51Ds were also built under licence in Australia by the Commonwealth Aircraft
Corporation (see below).
XP-51F, XP-51G and XP-51J (Lightweights never went into production)
The USAAF required airframes built to their acceleration standard of 8.33 g (82 m/s²), a higher load factor than that used by the British standard of 5.33 g (52 m/s²) for their fighters. Reducing the load factor to 5.33 would allow weight to be removed, and both the USAAF and the RAF were interested in the potential performance boost.
In 1943, North Ameri
can submitted a proposal to re-design the P-51D as model NA-105, which was accepted by the USAAF. Modifications included changes to the cowling, a simplified undercarriage with smaller wheels and disk brakes, and a larger canopy. The designation XP-51F was assigned to prototypes powered with V-1650 engines (a small number of XP-51Fs were passed to the British as the Mustang V) and XP-51G to those with reverse lend/lease Merlin 145M engines.
A third lightweight prototype powered by an Allison V-1710-119 engine was added to the development program. This aircraft was designated XP-51J. Since the engine was insufficiently developed, the XP-51J was loaned to Allison for engine development. None of these experimental “lightweights” went into production.
P-51H (Final Production Mustang)
The P-51H (NA-126) was the final production Mustang, embodying the experience gained in the development of the XP-51F and XP-51G aircraft. This aircraft, with minor differences as the NA-129, came too late to participate in World War II, but it brought the development of the Mustang to a peak as one of the fastest production piston engine fighters to see service.
The P-51H used the new V-1650-9 engine, a version of the Merlin that included Simmons automatic supercharger boost control with water injection, allowing War Emergency Power as high as 2218 hp (1,500 kW). Differences between the P-51D included lengthening the fuselage and increasing the height of the tailfin, which greatly reduced the tendency to yaw. The canopy resembled the P-51D style, over a somewhat raised pilot’s position. Service access to the guns and ammunition was also improved. With the new airframe several hundred pounds lighter, the extra power and a more streamlined radiator, the P-51H was among the fastest propeller fighters ever, able to reach 487 mph (784 km/h) at 25,000 ft (7,600 m).
The P-51H was designed to complement the P-47N Thunderbolt as the primary aircraft for the invasion of Japan with 2,000 ordered to be manufactured at Inglewood. Production was just ramping up with 555 delivered when the war ended. Production serial numbers:
P51H-5-NA 44-64180 – 44-64459
P51H-10-NA 44-64460 – 44-64714
Additional orders, already on the books, were cancelled. With the cutback in production, the variants of the P-51H with different versions of the Merlin engine were produced in either limited numbers or terminated. These included the P-51L, similar to the P-51H but utilizing the 2270 horsepower V-1650-11 Merlin engine, which was never built; and its Dallas-built version, the P-51M or NA-124 which utilized the V-1650-9A Merlin engine lacking water injection and therefore rated for lower maximum power, of which one was built out of the original 1629 ordered, serial number 45-11743.
Although some P-51Hs were issued to operational units, none saw combat in World War II, and in postwar service, most were issued to reserve units. One aircraft was provided to the RAF for testing and evaluation. Serial number 44-64192 was designated BuNo 09064 and used by the US Navy to test transonic airfoil designs, then returned to the Air National Guard in 1952. The P-51H was not used for combat in the Korean War despite its improved handling characteristics, since the P-51D was available in much larger numbers and was a proven commodity.
Many of the aerodynamic advances of the P-51 (including the laminar flow wing) were carried over to North American’s next generation of jet-powered fighters, the Navy FJ Fury and Air Force F-86 Sabre. The wings, empennage and canopy of the first straight-winged variant of the Fury (the FJ-1) and the unbuilt preliminary prototypes of the P-86/F-86 strongly resembled those of the Mustang before the aircraft were modified with swept-wing designs.