North American A-36 Apache

https://en.wikipedia.org/wiki/North_...an_A-36_Apache

The North American A-36 Apache (listed in some sources as "Invader", but also
called Mustang) was the ground-attack/dive bomber version of the North American
P-51 Mustang, from which it could be distinguished by the presence of
rectangular, slatted dive brakes above and below the wings. A total of 500 A-36
dive bombers served in the Mediterranean and Southeast Asia theaters during
World War II before being withdrawn from operational use in 1944.

With the introduction of the North American Mustang Mk.I with the Royal Air
Force's Army Co-operation Squadrons in February 1942, the new fighter began
combat missions as a low-altitude reconnaissance and ground-support aircraft.
Supplementing the Curtiss P-40 Tomahawks already in service, Mustang Is were
first supplied to No. 26 Squadron RAF, then rapidly deployed to 10 additional
squadrons by June 1942. First used in combat over the Dieppe Raid on 19 August
1942, a Mustang of No. 414 (RCAF) Squadron downed one of the formidable
Focke-Wulf Fw 190s, the first victory for a Mustang. Despite the limited
high-altitude performance of the Allison V-1710 engine, the RAF was enthusiastic
about its new mount, which "performed magnificently".

During the Mustang Mk. I's successful combat initiation, North American's
president Howard "Dutch" Kindelberger pressed the newly redesignated U.S. Army
Air Forces (USAAF) for a fighter contract for the essentially similar P-51, 93
of which had passed into the USAAF when the Lend-Lease contract with Britain ran
out of funds. The Mustang IA/P-51 used four 20 mm Hispano wing cannon in place
of the original armament, a combination of four wing-mounted .30 caliber (7.62
mm) M1919 Browning machine guns and four .50 caliber (12.7 mm) M2 Browning
machine guns, two of which were mounted in the wings, while the second pair was
mounted in the "chin", or lower engine cowling, and synchronized to fire through
the propeller. No funds were available for new fighter contracts in fiscal year
1942, but General Oliver P. Echols and Fighter Project Officer Benjamin S.
Kelsey wanted to ensure that the P-51 remained in production.

Since appropriations were available for an attack aircraft, Echols specified
modifications to the P-51 to turn it into a dive bomber. The contract for 500
A-36A aircraft fitted with bomb racks, dive brakes, and heavier-duty wing, was
signed by Kelsey on 16 April 1942, even before the first flight of the first
production P-51 in May 1942. With orders on the books, North American Aviation
(NAA) began modifying the P-51 to accept the bomb shackles which had already
been tested in a "long-range ferry" program that the RAF had stipulated.
Engineering studies totaling 40,000 hours and wind tunnel testing with a ?-scale
model were completed in June 1942. Utilizing the basic P-51 airframe and Allison
engine, structural reinforcing "beefed up" several high stress areas and "a set
of hydraulically operated dive brakes were installed in each main wing plane".
Due to the slightly inboard placement of the bomb racks and unique installation
of four cast aluminum dive brakes, a complete redesign of the P-51 wing was
required.

The USAAF later ordered 310 P-51As, which were essentially A-36s without the
dive-brakes and nose mounted weapons, leaving an armament of four wing-mounted
0.50 in (12.7 mm) Browning machine guns. An Allison V-1710-81 1,200 hp (895 kW)
was fitted and used the same radiator and air intake as the A-36A. The P-51A was
still fitted with bomb racks although it was not intended to be used primarily
as a fighter-bomber and the racks were mainly used to carry drop tanks.


Role
Ground-attack/dive bomber

Manufacturer
North American Aviation

Designer
Edgar Schmued

First flight
October 1942

Introduction
1942

Retired
1945

Primary user
United States Army Air Forces

Number built
500

Unit cost

$49,000


Developed from
P-51 Mustang

The A-36A-1-NA "Apache" (although Apache was the A-36A's official name, it was
rarely used) joined the 27th Fighter-Bomber Group (27th FBG) composed of four
squadrons based at Ras el Ma Airfield in French Morocco in April 1943 during the
campaign in North Africa. The 27th had a mixed component of Douglas A-20 Havocs
and A-36As while the second operational unit, the 86th Fighter Bomber Group
(Dive) arrived in March 1943 with the first pilots trained and qualified on the
A-36A. On 6 June 1943, both of these A-36A units flew combat missions directed
against the island of Pantelleria. The island fell to Allied attack and became
the home base for the two A-36A groups during the Allied invasion of Sicily. The
A-36A proved to be a potent weapon; it could be put into a vertical dive at
12,000 ft (3,658 m) with deployed dive brakes, thus limiting the dive speed to
390 mph (628 km/h) ("A36A-1 Flight Manual requires deployment before starting a
dive"). Pilots soon recognized that extending the dive brakes after "peel-off"
led to some unequal extension of the brakes due to varying hydraulic pressure,
setting up an invariable slight roll, which impeded aiming. Proper technique
soon cured this anomaly and, subsequently, pilots achieved extremely consistent
results. Depending on the target and defenses, the bomb release took place
between 2,000 ft and 4,000 ft (610 and 1,219 m), followed by an immediate sharp
"pull up."

Dive brakes in the wings gave the A-36A greater stability in a dive; however, a
myth has arisen that they were useless due to malfunctions or because of the
danger of deploying them and that they should be wired closed. Capt. Charles E.
Dills, 522d Fighter Squadron, 27th FBG, XIIth Air Force emphatically stated in a
postwar interview: "I flew the A-36 for 39 of my 94 missions, from 11/43 to
3/44. They were never wired shut in Italy in combat. This 'wired shut' story
apparently came from the training group at Harding Field, Baton Rouge, LA."

However, tactical reconnaissance training with P-51 and A-36 aircraft had
delivered some disquieting accident rates. At one time, A-36 training had
resulted in the type having "the highest accident rate per hour's flying time"
of any USAAF aircraft. The most serious incident involved an A-36A shedding both
wings when its pilot tried to pull out from a 450 mph (724 km/h) dive. Combat
units flying the A-36A were ordered to restrict their approach to a 70° "glide"
attack and refrain from using dive brakes. This order was generally ignored by
experienced pilots, but some units did wire dive brakes shut until modifications
made to the hydraulic actuators. Nevertheless, the A-36 was used with great
success as a dive-bomber, acquiring a reputation for precision, sturdiness and
silence.

Specifications (A-36A)

General characteristics
Crew: 1
Length: 32 ft 3 in (9.83 m)
Wingspan: 37 ft 0.25 in (11.28 m)
Height: 12 ft 2 in (3.71 m)
Loaded weight: 10,000 lb (4,535 kg)
Powerplant: 1 × Allison V-1710-87 liquid-cooled piston V12 engine, 1,325 hp (988
kW)

Performance
Maximum speed: 365 mph (315 kn, 590 km/h)
Cruise speed: 250 mph (215 kn, 400 km/h)
Range: 550 mi (478 nmi, 885 km)
Service ceiling: 25,100ft (7,650 m)

Armament

6 × 0.50 in (12.7 mm) M2 Browning machine guns
Up to 1,000 lb (454 kg) of bombs on two underwing hardpoints




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