Gluhareff Dart
The chief of design for the Vought-Sikorsky Aircraft Division of United Aircraft Corporation Michael Gluhareff, made several theoretical studies on the delta wing between 1936 and 1939, building a series of balsa flying models. In July 1941, he proposed to Igor Sikorsky the building of a low-aspect ratio tailless fighter with an ogival delta wing and a sweepback angle of 56 degrees.
The airplane concept was around the future XIV-2220 engine which design and building had been ordered by the US Army Air Force to the Chrysler Company by the beginning of 1941. It was a monstrous power plant with a length of 3.175 m and 2500 hp. formed by two V8 in tandem engines with a combined capacity of 36.38 lt.
Gluhareff estimated that the XIV-2220 was ideal for a very fast pusher fighter with a minimum frontal section, for better weight balance, the engine should be installed in front of the main landing gear, requiring the use of a drive shaft of 2.88 m for the pusher contra-rotating airscrews.
The cooling air intakes were in the wing roots, under the machine guns. The radiator was located behind the pilot and had an auxiliary fan connected to the engine.
For roll and pitch control the wings had elevons (named
flippers at the time). The directional control was obtained by conventional rudders mounted on two ventral fins.
The aircraft did not employ flaps, slots or spoilers.
In September 1942, when the heavy fighters P-38 and P-47 started experiencing problems of compressibility buffeting, it was thought that the delta wing could be used to delay the appearance of the undesired transonic phenomenon beyond 0.85 Mach.
Gluhareff ordered the building of a wind tunnel model to the Ludington-Griswold Inc. and the aerodynamic testing, finished in November 1942, looked very promising.
The design, named
Dart was presented to the US Army Air Force for testing in the Aircraft Laboratory and Aircraft Projects Section at Wright Field.
Several reasons influenced the decision of not manufacturing the
Dart. The compressibility buffeting problems were solved with the installation of an electric flap under the wings of the P-38 and P-47 and the ban on making certain combat maneuvers.
The XIV-2220 engine was not ready for testing until 1945 and the centrifugal turbojets of the time were too bulky for the available room in the small fighter.
Additionally, the pilots were reluctant to fly in the pusher types airplanes (XP-54, XP-55 and XP-56) due to the hazard of being hit by the propellers in case of bail out and the natural resistance of engineers to incorporate too many novelties in a single design.
On 26 May 1944 the USAAF received a proposal to transform the project in a glider bomb of 906 kg.
The
Dart design was patented for civil use after the war.
Gluhareff
Dart technical data
Engine: one 2,500 hp Chrysler XIV-2220-11, 16 cylinder, inverted ‘V’
, liquid-cooled engine driving a four-bladed contra-rotating airscrew.
Wingspan: 20 ft. (6,096 m), length: 26.5 ft. (8.077 m), height: 6.5 ft. (1.98 m), wing area: 278 sq. ft. (25 sq. m), estimated maximum weight: 6,623 lbs. (3,000 kg), estimated top speed: 500 mph (805 kph), estimated range: 1,120 mls (1,802 kph).