Grumman AF Guardian - Design and Development

Design and Development

The original design concept for the aircraft that would become the Guardian, the XTB2F of 1944, was to be a twin-engined aircraft with a 3,600 lb (1,633 kg) warload and a range of 3,700 mi (5,950 km). This was considered to be too large for practical use from an Essex class aircraft carrier, and was canceled in 1945, replaced by a modified Grumman F7F Tigercat, the XTSF-1.

However, this too was considered impractical, and another alternative, the internally developed Grumman Model G-70, was selected instead, being given the Navy designation XTB3F. This was designed as mixed-power aircraft, with a Pratt & Whitney Double Wasp radial engine in the nose and a Westinghouse 19XB turbojet in the tail. This was found to be unsuitable, and the jet engine was removed without ever having been used in flight. The XTB3F-1S carried a crew of two seated side-by-side and an armament of two 20 mm cannon and 4,000 lb (1,814 kg) of bombs, torpedoes and/or rockets, and made its first flight on 19 December 1945.

On 24 December 1945, the Navy changed the role of the aircraft from torpedo-bomber to anti-submarine warfare. All the required equipment could not be fitted into a single aircraft, consequently two variants would be produced, one as a "guppy" (hunter) and another as a "scrapper" (killer). The hunter aircraft would not carry any armament, but instead two additional crew members and a ventral radome for APS-20 search "eyes" (radar) and Electronic Countermeasures (ECM) "ears", consisting of an APR-98 Countermeasures Receiver and AP-70 Bearing Indicator. This aircraft, the XTB3F-1S, first flew in November 1948. The "killer" deleted the cannon of the torpedo bomber, but retained the bomb bay, added a third crewmember, a searchlight, and short-range radar, and (as the XTB3F-2S) first flew in January 1949.