THE 456th FIGHTER INTERCEPTOR SQUADRON

THE PROTECTORS OF  S. A. C.

 

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The North American A-36 Invader

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(Ground attack P-51 Mustang)

 

 

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North American A-36A Apache

The A-36A dive bomber was the first USAAF version of the Mustang developed for Britain in 1940. The A-36 fist flew in October 1942; production of 500 A-36As was completed by March 1943.

Unofficially named "Invaders", A-36As were assigned to the 27th and 86th Bombardment Groups (Dive), later re-designated as Fighter-Bomber Groups. In June 1943 the plane went into action from North Africa. During the Italian campaign, A-36A pilots flew bomber escort and strafing missions as well as ground support bombing attacks. A-36As also served with the 311th Fighter Bomber Group in India. Dive brakes in the wings gave greater stability in a dive, but they were sometimes wired closed due to malfunctions. In 1944 AAF A-36As were replaced by P-51s and P-47s when experience showed that these high-altitude fighters, equipped with bomb racks, were more suitable for low-level missions than the A-36As.

 

SPECIFICATIONS:
Span:
37 ft.
Length: 32 ft. 3 in.
Height: 12 ft. 2 in.
Weight: 10,000 lbs. loaded
Armament: Six .50-cal. machine guns, 1,000 lbs of bombs externally
Engine: Allison V-1710 of 1,325 hp
Cost: $49,000
Serial number: 42-83665
C/N: 97-15883
Other registrations: N39502, N6458C

PERFORMANCE:
Maximum speed:
365 mph
Cruising speed: 250 mph
Range: 550 miles
Service ceiling: 25,100 ft.
 

 

 

NORTH AMERICAN A-36A APACHE / Invader

(dive bomber or ground attack variant of the P-51 Mustang)

 

 

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North American A-36C Invader 

(with six 50 caliber machine-guns and two 500 lb. bombs and six HiVar Rockets.)

The North American A-36A Apache dive-bomber was the first AAF P-51A version of the British "Mustang" developed for Britain in 1940. The A-36 first flew in Oct. 1942; production of 500 A-36As was completed by March 1943. Originally, an Allison engine powered the P-51A Apache or the RAF Mustang- Mark I ground attack and photo-reconnaissance aircraft. Later versions used the Packard Merlin engine. These were known as the British Mustang II or III or the American A-36B or C Invader, respectively.

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North American Mustangs with 20mm Hispano cannons are being prepared for the British RAF (note insignia) under Lend-lease. 

Notice the wood wheels for moving the airplane about factory airfield for final preparation. Rubber was in dismal supply.

The first A-36A flew on September 21, 1942. Deliveries of the A-36A were completed by the following March. The A-36A equipped the 27th and 86th Bombardment Groups (Dive) based in Sicily and in Italy. The groups were later re-designated as Fighter-Bomber Groups.

A-36s were painted initially in olive drab and light-gray finish and were painted with yellow bands and yellow circles around the national insignia. Both of these air groups arrived in North Africa in April of 1943 just after the end of the Tunisian campaign. They saw their first action during attacks on the island of Pantelleria, with the first sortie being flown on June 6, 1943. The A-36A was involved in the taking of Monte Cassino, and participated in the sinking of the Italian liner Conte di Savoia

In June 1943, the Invader went into action from North Africa. During the Italian campaign, A-36 pilots flew bomber escort and strafing missions as well as ground support bombing attacks. A-36s also served with the 311th Fighter Bomber Group in India. In 1944, AAF A-36As were replaced by A-36Cs (modified P-51Ds) and P-47D Thunderbolts when experience showed that these fighters, equipped with bomb racks, were more suitable for missions for targets-of-opportunity than the A-36A.

In a ground attack configuration, the Invader carried two 500 lb. bombs and two types of rockets: 4.5 inch M-8 in tubes mounted in clusters of three, and later, HiVar (high velocity anti-armor rockets. Other armament variations allowed replacing the four or six 0.5 caliber machine-guns with four 20mm Hispano cannons.

 

 The A-36 was known by several different names. The Apache was the name that the US Army initially assigned to the P-51, but there was an effort to change the name to Invader following the invasion of Sicily. However, most people applied the name Mustang to the A-36.

 

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The A-36A differed from the Mustang version in having a set of hydraulically operated perforated door-type dive brakes mounted at approximately mid-chord on both the upper and lower wing surfaces outboard of the wing guns. The brakes were normally recessed into the wings, but were opened to 90 degrees by a hydraulic jack to hold diving speeds down to 250 mph. A rack was fitted under each wing for a 500-pound bombs, a 75 US gallon drop tank, or smoke-curtain equipment. A built-in armament of six 0.50-inch machine guns (two in lower fuselage nose, four in the wings) was fitted, however the two nose guns were often omitted in service. The wing guns were moved closer to the main landing gear strut in order to minimize stress under taxi and takeoff conditions. The engine was the Allison V-1710, rated at 1325 hp at 3000 feet. Normal and maximum loaded weights rose to 8370 pounds and 10,700 pounds, and the maximum speed in clean condition fell to 356 mph at 5000 feet and 310 mph with the two 500-lb bombs fitted. With the bombs, range and service ceiling were 550 miles and 25,000 feet respectively. 

 

 Several sources list the Invader as not being particularly effective during combat. Archives at Maxwell Air Force Base states that this is not correct. Although losses during low-level attacks were rather high, the A-36A was a good dive-bomber and stable and effective in ground attack. The engine was quiet, and it was often possible for an A-36 to get nearly on top of an enemy before he realized that an attack was imminent.

 

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British mechanics repair a Mustang Mark II in France, July 1944

Dive-bombing was usually initiated from an altitude of 10,000 feet to 12,000 feet, with bombing speed held to around 300 mph by the dive brakes. The bombs were dropped at an altitude of 3000 feet, and pullout was at approximately 1500 feet. The Invader was fairly rugged and easy to maintain in the field. All A-36s could consistently stay within 20 feet of the deck and could maneuver easily around trees, buildings, and other obstacles while strafing. The A-36 was able to take a considerable amount of battle damage and still return to base.

A-36As did not see very much air-to-air combat, since it was optimized for low-altitude operations and lost its effectiveness above 10,000 feet altitude. It was generally believed that the A-36A Invader was no match for the Messerschmitt Bf 109 at high altitudes, and that it was therefore best for A-36A pilots to avoid such encounters if at all possible. If air-to-air combat was unavoidable, it was thought best to force the battle down to altitudes below 8000 feet, where maximum advantage could be taken of the A-36A's excellent low-altitude performance. Although it was not a fighter, the Invader claimed 101 enemy aircraft destroyed in air-to-air combat. One of the pilots of the 27th Fighter Bomber Group, Lt Michael T. Russo, became the only ace in the Allison-engined Mustang/Apache, although several of his A-36A colleagues scored victories as well.

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An A-36B Invader of 311th Fighter Bomber Group attacks a Japanese air field with 4.5 inch M-8 rockets.

 

A myth has sprung up about the A-36A's dive brakes. According to some stories, the dive brakes of the A-36A were next to useless and were deliberately wired shut at the manufacturers so that they could not be used. This story is incorrect. On the contrary, the dive brakes proved to be quite effective and the aircraft was so stable with the dive brakes extended that bombing while in a dive was exceptionally accurate.  There were some 'field' situations where dive brakes were wired closed due to malfunctions involving maintenance and spare parts.

 

Dive brakes were discontinued because of war production needs. Therefore only 500 A-36As with Allison engines and dive brakes were built. Later A-36B and C models were equipped with Hi-Var rockets and did not have dive brakes. B model A-36s were actually P-51B or C models and an A-36C was a P-51D relegated to ground attack roles.

 

One A-36A was supplied to the RAF in March of 1943 for experimental purposes. Its RAF serial number was EW998. 

Very few A36As survive today. A-36A Serial Number 42-83665 is on display at the WPAFB Museum in Dayton, Ohio. 42-83731 is with the Lone Star Flight Museum in Texas. 43-83738 is restored as a P-51B at the Warhawk Air Museum in Boise, ID. Another A-36A is with the Collings Foundation.

Serial numbers for A-36As were 42-83663/84162.

 

 

The North American A-36

 

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The A-36

Only after Pearl Harbor did the US Army finally agree to order the Mustang for its own use. General H. H. "Hap" Arnold, Chief of Staff of the USAAF, was instrumental in breaking up the bureaucratic log-jam and getting the Army to relent and order the Mustang for its own use. On April 16, 1942, the Army finally ordered 500 NA-97s. The NA-97 was a ground attack version and was designated A-36A (in the attack series rather than the fighter series). Serial numbers were 42-83663/84162.

The A-36 seems to have been known by several different names--it was initially called *Apache*, which was the name that the Army initially assigned to the P-51, but there was an effort to change the name to Invader following the invasion of Sicily. However, the name Mustang was generally applied by most people to the A-36.

The A-36A differed from previous Mustang versions in having a set of hydraulically-operated perforated door-type dive brakes mounted at approximately mid-chord on both the upper and lower wing surfaces outboard of the wing guns. The brakes were normally recessed into the wings, but were opened to 90 degrees by a hydraulic jack to hold diving speeds down to 250 mph. A rack was fitted under each wing for a 500-pound bombs, a 75 US gallon drop tank, or smoke-curtain equipment. A built-in armament of six 0.50-inch machine guns (two in lower fuselage nose, four in the wings) was fitted, however the two nose guns were often omitted in service. The wing guns were moved closer to the main landing gear strut in order to minimize stress under taxi and takeoff conditions. The engine was the Allison V-1710-87 (F21R), rated at 1325 hp at 3000 feet. Normal and maximum loaded weights rose to 8370 pounds and 10,700 pounds, and the maximum speed in clean condition fell to 356 mph at 5000 feet and 310 mph with the two 500-lb bombs fitted. With the bombs, range and service ceiling were 550 miles and 25,100 feet respectively.

The first A-36A flew on September 21, 1942. Deliveries of the A-36A were completed by the following March. The A-36A equipped the 27th and 86th Fighter Bomber Groups based in Sicily and in Italy. They initially were painted in olive-drab and light-gray finish and were painted with yellow wing bands and yellow circles around the national insignia. Both of these Groups arrived in North Africa in April of 1943 just after the end of the Tunisian campaign. They saw their first action during aerial attacks on the island of Pantelleria, with the first sortie being flown on June 6, 1943. The A-36A was involved in the taking of Monte Cassino, and participated in the sinking of the Italian liner Conte di Savoia.

The only other A-36 user was the 311th Fighter Bomber Group, based in India. It saw extensive use in the China-Burma-India theatre.

Several sources list the Invader as not being particularly effective during combat. It seems that this is not strictly correct. Although losses during low-level attacks were rather high, the A-36 was actually a good dive bomber and it was a stable and effective ground strafer. The engine was very quiet, and it was often possible for an A-36 to get nearly on top of an enemy before he realized that an attack was imminent. Dive bombing was usually initiated from an altitude of 10,000 feet to 12,000 feet, with bombing speed held to around 300 mph by the dive brakes. The bombs were dropped at an altitude of 3000 feet, and pullout was at approximately 1500 feet. The Invader was fairly rugged and easy to maintain in the field. The A-36 could consistently stay within 20 feet of the deck and could easily maneuver around trees, buildings, and other obstacles while strafing. The A-36A was able to take a considerable amount of battle damage and still return to base. Nevertheless, a total of 177 A-36As were lost in action.

The A-36s did not see very much air-to-air combat, since it was optimized for low-altitude operations and lost its effectiveness above 10,000 feet altitude. It was generally believed that the A-36 Invader was no match for the Messerschmitt Bf 109 at high altitudes, and that it was therefore best for A-36 pilots to avoid such encounters if at all possible. If air-to-air combat was unavoidable, it was thought best to force the battle down to altitudes below 8000 feet, where maximum advantage could be taken of the A-36A's excellent low-altitude performance. Although it was not a fighter, the Invader claimed 101 enemy aircraft destroyed in air-to-air combat. One of the pilots of the 27th Fighter Bomber Group, Lt Michael T. Russo, became the only ace in the Allison-engine Mustang, although several other of his colleagues did score victories as well.

A sort of urban legend has sprung up about the A-36A's dive brakes. According to some stories, the dive brakes of the A-36A were next to useless and were deliberately wired shut at the manufacturers so that they could not be used. This story is totally incorrect. On the contrary, the dive brakes proved to be quite effective in combat, and the aircraft was so stable with the dive brakes extended that bombing while in a dive was particularly accurate. The origin of this legend seems to have been in the United States, at a time before the Invaders first went overseas. It seems that A-36A pilots were told by their officers in the USA that their dive brakes would be all but useless in combat and it would be best if they simply wired them shut. This turned out to be incorrect, and the dive brakes were used to great effect throughout the Sicilian campaign and the Italian invasion.

One A-36A was supplied to the RAF in March of 1943 for experimental purposes. Its RAF serial number was EW998.

There are very few A-36As still surviving today. A-36A Ser No 42-83665 is on display at the WPAFB Museum in Dayton, Ohio. 42-83731 is with the Lone Star Flight Museum in Texas. 43-83738 is currently undergoing restoration as a P-51B at the Warhawk Air Museum in Boise, ID. Another A-36A is with the Collings Foundation, where it is undergoing restoration.

Serial numbers of the A-36 were 42-83663/84162.

Joe Baugher

Sources:

  1. American Combat Planes, Ray Wagner, Third Enlarged Edition, Doubleday, 1982.
     
  2. The American Fighter, Enzo Angelucci and Peter Bowers, Orion Books, 1987.
     
  3. War Planes of the Second World War, Fighters, Volume Four, William Green, Doubleday 1964.
     
  4. United States Military Aircraft since 1909, Gordon Swanborough and Peter M. Bowers, Smithsonian, 1989.
     
  5. Fighting Mustang: The Chronicle of the P-51, William N. Hess, Doubleday, 1970.
     
  6. Classic Warplanes: North American P-51 Mustang, Bill Gunston, Gallery Books, 1990.
     
  7. Famous Fighters of the Second World War, Volume I, William Green, 1967.
     
  8. British Military Aircraft Serials, 1912-1969, Bruce Robertson, Ian Allen, 1969.
     
  9. North American P-51 Mustang: The Fighter That Won the War, Bill Gunston and Robert F. Dorr, Wings of Fame, Vol 1, 1995.
     
  10. E-Mail from Mark Waddell.
     
  11. E-mail from Bob Storck on surviving A-36As.

 

 

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02/10/2014

 

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