The Loening PW-2 was a single seat monoplane fighter that was developed from the earlier M-8, and that was tested by the US Army but not accepted for production.
The Loening M-8 had been a shoulder mounted two-seat monoplane, powered by a 300hp Wright Hispano-Suiza engine, developed during 1918 in an attempt to produce an American aircraft with better performance than the Bristol Fighter. The design was a success, and 5,000 were ordered but the war ended before production could get underway and the order was cancelled. The M-8 did enter production after the US Navy ordered fifty four M-8s, which it used as observation aircraft, although most of these aircraft were built at the Naval Aircraft Factory.
In 1920 the US Army ordered three prototypes of a new single seat fighter to be developed from the M-8. The new aircraft was given the designation PW-2, or Pursuit, Water-cooled, second in the 1919-1924 sequence. Like the M-8, the PW-2 was a shoulder winged monoplane, powered by the 300hp Wright engine, with the wings braced by struts that connected the bottom of the fuselage to the middle of each wing.
Perhaps the biggest change between the M-8 and the PW-2 was the position of the cockpit. On the M-8 the two open cockpits were mounted in the top of the fuselage, level with the top of the wings. On the PW-2 the single cockpit was cut out of the fuselage level with the trailing edge of the wing. This contributes to the visual impression that the PW-2 was a parasol wing aircraft (with the wing mounted above the fuselage), but in fact the wing was carried on the main fuselage longerons. In pictures these longerons can just be seen running above the sides of the open cockpit. The parasol image was further enhanced by the lack of any covering for the upper part of the fuselage under the wing.
The first prototype was a static test machine. The second was built with a single fin and rudder, the third with twin fins and rudders. These aircraft were delivered during 1921 and underwent flight tests beginning in September 1921. The Army then ordered two improved PW-2As. These used a single balanced rudder, with no fin. The first was completed as a PW-2A, with the Wright engine and the second as the PW-2B, using a Packard engine and a smaller wing.
Eight more PW-2As were ordered but as more testing was carried out a number of problems with the design were discovered, including a tendency to wing flutter.
On 20 October 1922 First Lieutenant Harold R Harris became the first American Army aviator to successfully use a parachute to escape from a crash. He was testing the second PW-2A from the second batch at McCook Field when it began to vibrate. Harris realised that part of the left wing had failed and was able to safely bail out. He thus became the first member of a new 'Caterpillar club', formed for people who had been forced to parachute out of an aircraft. Soon after Harris's escape the Air Service decided to equip all passengers and crew in their aircraft with parachutes. As a result of this crash the remaining six aircraft were cancelled. Loening abandoned the monoplane fighter and moved on to the biplane Loening PA-1.
PW-2 was the designation given to the three prototypes - the static test bed, the single rudder and the twin rudder versions.
PW-2A was the designation given to the first of two improved prototypes with the balanced rudder and the eight further aircraft ordered but cancelled after two had been delivered. Three aircraft were completed as PW-2As.
The PW-3A was the designation given to the second aircraft ordered as a PW-2A. It was built with a 350hp Packard 1A-1237 water cooled engine and had its wingspan reduced from 39ft 9in to 34ft 1.25in. The PW-3A reached a top speed of 140mph, a 4mph increase on the PW-2A.
Engine: Wright-Hispano-Suiza Model H
Span: 39ft 9in
Length: 26ft 0.5in
Height: 8ft 1in
Empty Weight: 1,786lb
Loaded Weight: 2,799lb
Maximum Speed: 136mph
Climb rate: 9.8mins to 10,000ft
Endurance: 2.5 hours