aircraft – Dominie three aircraft order |de Havilland Dominie |- |B.1/39 | |"Ideal Bomber" four-engined heavy bomber with 9,000 lb bomb load and 20mm cannon defence (revised B.19/38) – work suspended June 1940 |Handley Page H.P.60, Bristol Type 159, a Gloster submission, Armstrong Whitworth AW.68 |- |T.4/39 |OR.68 |Single-engined trainer |Airspeed Cambridge – (two prototypes ordered, no production contract) |- |R.5/39 | |Long-range patrol flying boat – Sunderland replacement – superseded by R.14/40 (q.v.) |Saunders-Roe S.38 – later cancelled |- |N.8/39 | |Naval two-seat carrier-borne fighter – Roc replacement – replaced by N.5/40 |see N.5/40 |- |N.9/39 | |Naval two-seat carrier-borne fighter – Fulmar replacement – replaced by N.5/40 |see N.5/40 |- |F.17/39 | |Long-range fighter development of Bristol Beaufort – written for Beaufighter |Bristol Beaufighter |- |F.18/39 | |Fighter – Hurricane/Spitfire replacement |Martin-Baker M.B.3, Martin-Baker M.B.5 |- |19/39 | |Twin-engine transport aircraft – order for Hertfordshire later cancelled |de Havilland Hertfordshire |- |20/39 | |Twin-engine communications aircraft – order for No. XXIV Squadron RAF |de Havilland Flamingo |- |21/39 | |Twin-engine VIP transport aircraft – order for The King's Flight |de Havilland Flamingo |- |F.22/39 |OR.76 |Fighter fitted with heavy-calibre nose-mounted gun |Vickers 414 Vickers Type 432 – also tests with Vickers Type 439 testbed – specification later cancelled |- |B.23/39 | |Very high altitude version of Wellington capable of operating at 40,000 ft |Vickers Wellington V |- |E.28/39 | |Experimental aircraft using Whittle jet-propulsion with provision for 4 × 0.303 machine guns |Gloster E.28/39 |} 1940–1949 Post 1949 specifications. Air Staff Operational Requirements/targets Naval requirement/Aircraft, Naval Staff requirements General Staff Requirements For Aircraft See also Operational Requirement (OR) British military aircraft designation systems General Staff Target – the British Army equivalent Specification (technical standard) List of Operational Requirements for nuclear weapons References Notes Citations Bibliography Aeroplane Monthly'' magazine. Various articles, various issues, 1973–1987. Further reading : This is a combined volume made up of External links British military aircraft United Kingdom Air Ministry Air Ministry specifications United Kingdom defence procurement