North American P-51 Mustang

About North American P-51 Mustang – Source Wikipedia

Role: Fighter
National origin: United States
Manufacturer: North American Aviation
First flight: 26 October 1940
Introduction: 1942
Status: Retired from military service 1984, still in civil use
Primary users: United States Army Air Forces, Royal Air Force, Chinese Nationalist Air Force and numerous others
Number built: More than 15,000
Unit cost: US$ 50,985 in 1945
Variants: North American A-36, Rolls-Royce Mustang Mk.X, Cavalier Mustang
Developed into: North American F-82 Twin Mustang, Piper PA-48 Enforcer
Total number built: 16,766

Specifications (P-51D Mustang)
Data from Erection and Maintenance Manual for P-51D and P-51K. The Great Book of Fighters, and Quest for Performance

General characteristics

• Crew: One
• Length: 32 ft 3 in (9.83 m)
• Wingspan: 37 ft 0 in (11.28 m)
• Height: 13 ft 4½ in (4.08 m:tail wheel on ground, vertical propeller blade.)
• Wing area: 235 ft² (21.83 m²)
• Empty weight: 7,635 lb (3,465 kg)
• Loaded weight: 9,200 lb (4,175 kg)
• Max. takeoff weight: 12,100 lb (5,490 kg)
• Powerplant: 1 × Packard V-1650-7 liquid-cooled supercharged V-12, 1,490 hp (1,111 kW) at 3,000 rpm; 1,720 hp (1,282 kW) at WEP
• Zero-lift drag coefficient: 0.0163
• Drag area: 3.80 ft² (0.35 m²)
• Aspect ratio: 5.83

Performance

• Maximum speed: 437 mph (703 km/h) at 25,000 ft (7,600 m)
• Cruise speed: 362 mph (580 km/h)
• Stall speed: 100 mph (160 km/h)
• Range: 1,650 mi (2,755 km) with external tanks
• Service ceiling:  41,900 ft (12,800 m)
• Rate of climb: 3,200 ft/min (16.3 m/s)
• Wing loading: 39 lb/ft² (192 kg/m²)
• Power/mass: 0.18 hp/lb (300 W/kg)
• Lift-to-drag ratio: 14.6
• Recommended Mach limit: 0.8

Armament

• 6× 0.50 caliber (12.7mm) M2 Browning machine guns with 1,880 total rounds (400 rounds for each on the inner pair, and 270 rounds for each of the outer two pair)
• 2× hardpoints for up to 2,000 lb (907 kg) of bombs
• 6 or 10× T64 5.0 in (127 mm) H.V.A.R rockets (P-51D-25, P-51K-10 on)

The North American Aviation P-51 Mustang was an American long-range, single-seat fighter and fighter-bomber used during World War II, the Korean War and several other conflicts. During World War II, Mustang pilots claimed 4,950 enemy aircraft shot down, second only to the Grumman F6F Hellcat among Allied aircraft.
It was conceived, designed and built by North American Aviation (NAA), under the direction of lead engineer Edgar Schmued, in response to a specification issued directly to NAA by the British Purchasing Commission; the prototype NA-73X airframe was rolled out on 9 September 1940, albeit without an engine, 102 days after the contract was signed and it was first flown on 26 October.
The Mustang was originally designed to use a low-altitude rated Allison V-1710 engine, and was first flown operationally by the Royal Air Force (RAF) as a tactical-reconnaissance aircraft and fighter-bomber. The definitive version, the P-51D, was powered by the Packard V-1650-7, a license-built version of the Rolls-Royce Merlin 60 series two-stage two-speed supercharged engine, and armed with six .50 caliber (12.7 mm) M2 Browning machine guns.
From late 1943, P-51Bs (supplemented by P-51Ds from mid-1944) were used by the USAAF’s Eighth Air Force to escort bombers in raids over Germany, while the RAF’s 2 TAF and the USAAF’s Ninth Air Force used the Merlin-powered Mustangs as fighter-bombers, roles in which the Mustang helped ensure Allied air superiority in 1944. The P-51 was also in service with Allied air forces in the North African, Mediterranean and Italian theatres, and saw limited service against the Japanese in the Pacific War.
At the start of Korean War, the Mustang was the main fighter of the United Nations until jet fighters such as the F-86 took over this role; the Mustang then became a specialized fighter-bomber. Despite the advent of jet fighters, the Mustang remained in service with some air forces until the early 1980s. After World War II and the Korean War, many Mustangs were converted for civilian use, especially air racing.

Design and development

In April 1938, shortly after the German Anschluss of Austria, the British government established a purchasing commission in the United States, headed by Sir Henry Self. Self was given overall responsibility for Royal Air Force (RAF) production and research and development, and also served with Sir Wilfrid Freeman, the “Air Member for Development and Production”. Self also sat on the British Air Council Sub-committee on Supply (or “Supply Committee”) and one of his tasks was to organize the manufacturing and supply of American fighter aircraft for the RAF. At the time, the choice was very limited, as no U.S. aircraft then in production or flying met European standards, with only the Curtiss P-40 Tomahawk coming close. The Curtiss-Wright plant was running at capacity, so P-40s were in short supply.
North American Aviation (NAA) was already supplying its Harvard trainer to the RAF, but was 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 license from Curtiss. Kindelberger said NAA could have a better aircraft with the same engine in the air sooner than establishing a production line for the P-40. The Commission stipulated armament of four .303 in (7.7 mm) machine guns, the Allison V-1710 liquid-cooled engine, a unit cost of no more than $40,000, and delivery of the first production aircraft by January 1941. In March 1940, 320 aircraft were ordered by Sir Wilfred Freeman who had become the executive head of Ministry of Aircraft Production (MAP), and the contract was promulgated on 24 April.
The design, known as the NA-73X, followed the best conventional practice of the era, but included several new features. One was a wing designed using laminar flow airfoils which were developed co-operatively by North American Aviation and the National Advisory Committee for Aeronautics (NACA). These airfoils generated very low drag at high speeds. During the development of the NA-73X, a wind tunnel test of two wings, one using NACA 5-digit airfoils and the other using the new NAA/NACA 45-100 airfoils, was performed in the University of Washington Kirsten Wind Tunnel. The results of this test showed the superiority of the wing designed with the NAA/NACA 45-100 airfoils. The other feature was a new radiator design that exploited the “Meredith Effect”, in which heated air exited the radiator as a slight amount of jet thrust. Because NAA lacked a suitable wind tunnel to test this feature, it used the GALCIT 10 ft (3.0 m) wind tunnel at Caltech. This led to some controversy over whether the Mustang’s cooling system aerodynamics were developed by NAA’s engineer Edgar Schmued or by Curtiss, although NAA had purchased the complete set of P-40 and XP-46 wind tunnel data and flight test reports for US$56,000. The NA-73X was also one of the first aircraft to have a fuselage lofted mathematically using conic sections; this resulted in the aircraft’s fuselage having smooth, low drag, surfaces. To aid production, the airframe was divided into five main sections —forward, center, rear fuselage and two wing halves—all of which were fitted with wiring and piping before being joined.
The prototype NA-73X was rolled out in September 1940 and first flew on 26 October 1940, respectively 102 and 149 days after the order had been placed, an uncommonly short gestation period. The prototype handled well and accommodated an impressive fuel load. The aircraft’s two-section, semi-monocoque fuselage was constructed entirely of aluminum to save weight. It was armed with four .30 in (7.62 mm) M1919 Browning machine guns, two in the wings and two mounted under the engine and firing through the propeller arc using gun synchronizing gear.
While the United States Army Air Corps (USAAC) could block any sales it considered detrimental to the interests of the US, the NA-73 was considered to be a special case because it had been designed at the behest of the British. In September 1940 a further 300 NA-73s were ordered by MAP. To ensure uninterrupted delivery Colonel Oliver P. Echols arranged with the Anglo-French Purchasing Commission to deliver the aircraft, and NAA gave two examples to the USAAC for evaluation.

Operational history

U.S. operational service

Prior to the P-51

Pre-war doctrine of most bomber forces was to attack at night when the bombers would be effectively immune to interception. In theory, the loss in accuracy due to limited visibility was a high price to pay, protecting small targets from attack. The RAF did attempt several long-range daylight raids early in the war using the Vickers Wellington, but suffered such high casualties that they abandoned the effort quickly. The Luftwaffe had the advantage of bases in France that allowed their fighters to escort the bombers at least part way on their missions. This strategy proved ineffective, as the RAF fighters ignored the escorts and attacked the bombers. The Germans abandoned day bombing and switched to night bombing during The Blitz of 1940–41.
American pre-war doctrine developed out of an isolationist policy that was primarily defensive. The B-17 had originally been designed to attack shipping at long range from U.S. bases. For this role it needed to be able to attack in daylight and used the advanced Norden bombsight to improve accuracy. As the bomber developed, more and more defensive armament was added to outgun the fighters it would face. In light of this heavy defensive firepower, the USAAC came to believe that tightly packed formations of B-17s would have so much firepower that they could fend off fighters on their own. In spite of evidence to the contrary from the RAF and Luftwaffe, this strategy was believed to be sound. When the U.S. entered the war they put this strategy into force, building up a strategic bomber force based in Britain.
The 8th Air Force started operations from Britain in August 1942; at first, because of the limited scale of operations, there was no conclusive evidence that the American doctrine was failing. In the 26 operations which had been flown to the end of 1942 the loss rate had been under 2%. In January 1943, at the Casablanca Conference, the Allies formulated the Combined Bomber Offensive (CBO) plan for “round-the-clock” bombing by the RAF at night and the USAAF by day. In June 1943, the Combined Chiefs of Staff issued the Pointblank Directive to destroy the Luftwaffe before the invasion of Europe, putting the CBO into full implementation. Following this, the 8th Air Force’s heavy bombers conducted a series of deep-penetration raids into Germany, beyond the range of escort fighters. German fighter reaction was fierce and bomber losses were severe—20% in an October 14 attack on the German ball-bearing industry. This made it too costly to continue such long-range raids without fighter escort.
The Lockheed P-38 Lightning had the range to escort the bombers, but was only available in small numbers in the European theater due to its Allison engines proving difficult to maintain. It was also a very expensive aircraft to build and operate. The Republic P-47 Thunderbolt was capable of meeting the Luftwaffe on more than even terms, but did not at the time have sufficient range. The Luftwaffe quickly identified its maximum range, and their fighters waited for the bombers just beyond the point where the Thunderbolts had to turn back.

P-51s and civil aviation

Many P-51s were sold as surplus after the war, often for as little as $1,500. Some were sold to former wartime fliers or other aficionados for personal use, while others were modified for air racing.
One of the most significant Mustangs involved in air racing was a surplus P-51C-10-NT (44-10947) purchased by film stunt pilot Paul Mantz. The aircraft was modified by creating a “wet wing”, sealing the wing to create a giant fuel tank in each wing, which eliminated the need for fuel stops or drag-inducing drop tanks. This Mustang, called Blaze of Noon, came in first in the 1946 and 1947 Bendix Air Races, second in the 1948 Bendix, and third in the 1949 Bendix. He also set a U.S. coast-to-coast record in 1947. The Mantz Mustang was sold to Charles F. Blair Jr (future husband of Maureen O’Hara) and renamed Excalibur III. Blair used it to set a New York-to-London (c. 3,460 mi/5,568 km) record in 1951: 7 h 48 min from takeoff at Idlewild to overhead London Airport. Later that same year, he flew from Norway to Fairbanks, Alaska, via the North Pole (c. 3,130 mi/5,037 km), proving that navigation via sun sights was possible over the magnetic north pole region. For this feat, he was awarded the Harmon Trophy, and the Air Force was forced to change its thoughts on a possible Soviet air strike from the north. This Mustang now resides in the National Air and Space Museum at Steven F. Udvar-Hazy Center.

The most prominent firm to convert Mustangs to civilian use was Trans-Florida Aviation, later renamed Cavalier Aircraft Corporation, which produced the Cavalier Mustang. Modifications included a taller tailfin and wingtip tanks. A number of conversions included a Cavalier Mustang specialty: a “tight” second seat added in the space formerly occupied by the military radio and fuselage fuel tank.
In 1958, 78 surviving RCAF Mustangs were retired from service’s inventory and were ferried by Lynn Garrison an RCAF pilot, from their varied storage locations to Canastota, New York where the American buyers were based. In effect, Garrison flew each of the surviving aircraft at least once. These aircraft make up a large percentage of the aircraft presently flying worldwide.
In the late 1960s and early 1970s, when the United States Department of Defense wished to supply aircraft to South American countries and later Indonesia for close air support and counter insurgency, it turned to Cavalier to return some of their civilian conversions back to updated military specifications.
In the 21st century a P-51 can command a price of more than $1 million, even for only partially restored aircraft. According to the FAA there are 204 privately owned P-51s in the U.S., most of which are still flying, often associated with organizations such as the Commemorative Air Force (formerly the Confederate Air Force).
On 16 September 2011, The Galloping Ghost, a modified P-51 piloted by Jimmy Leeward of Ocala, Florida, crashed during an air race in Reno, Nevada. Leeward and at least nine people on the ground were killed when the racer suddenly crashed near the edge of the grandstand.

Production

Source: U.S. Military Aircraft Designations and Serials since 1909

NA.73X
Prototype, one built

A-36 Apache / A-36 Invader
Attack variant of the initial production run for the UK, initially named Invader but very quickly re-named Apache

P-51
150 built

P-51A
310 built at Inglewood, California

P-51B
1,988 built at Inglewood

P-51C
1,750 built at Dallas, Texas

P-51D
A total of 8,156 were built: 6,502 at Inglewood, 1,454 at Dallas and 200 by CAC at Fisherman’s Bend, Australia

XP-51F
Three built

XP-51G
Two built

P-51H
555 built at Inglewood

XP-51J
Two built

P-51K
1,500 built

P-51L
None built – cancelled

P-51M
One built at Dallas

Mustang Mk.I
620 built

Mustang Mk.III
852 built

Mustang Mk.IV
281 built

Mustang Mk.IVA
595 built

Rolls-Royce Mustang Mk.X
Five prototype conversions only – two Mustang Mk.I airframes were initially trial fitted with Rolls-Royce Merlin 65 engines in mid-late 1942, in order to test the performance of the aircraft with a powerplant better adapted to medium/high altitudes. The successful conversion of the Packard V-1650 Merlin-powered NAA P-51B/C equivalent rendered this experiment as superfluous. Although the conversions were highly successful, the planned production of 500 examples was cancelled.

Commonwealth CA-17 Mustang Mk.20
80 Australian assembled P-51Ds, (100 delivered as kits but only 80 assembled).

Commonwealth CA-18 Mustang Mk. 21, Mk.22 and Mk.23
Licence production of 120 of the P-51D model, of which the Mk.21 and Mk.22 used the American-built Packard V-1650-3 or V-1650-7 and the Mk.23, which followed the Mk.21, was powered by a Rolls-Royce Merlin 66 or Merlin 70 engines. 170 were ordered but only 120 were built.