27. Short SC.1
Work began in 1954 to design a test aircraft that could demonstrate the utility of the recently developed Rolls-Royce RB.108 lift engine, producing 2,130 lb thrust each (a thrust to weight of 8:1). The Short Brothers SC.1 was powered by four RB.108 lift engines vertically mounted on gimbals in the center fuselage and one RB.108 cruise engine in the rear for forward flight. Ground carts were used to spin the lift engines up to speed for take-off; for landing, cruise engine bleed air was used. The SC.1 was designed to study hover, transition and low-speed flight, and had a fixed landing gear. Gross weight was 7,700 lb, with a total vertical thrust 8,600 lb. Overall length was 30 ft; the wingspan was 23.5 ft. Bleeds from the four lift engines powered nose, tail and wing tip reaction jets for control at low speeds. First CTOL flight was made on 2 April 1957, first tethered vertical flight was on 26 May 1958, first free vertical flight was on 25 October 1958; first transition was on 6 April 1960. The SC.1 experienced the typical suck-down and hot-gas ingestion problems discovered during V/STOL development programs. It appeared at the Farnborough air show in 1960 and Paris air show in 1961 (for the latter it flew the English Channel both ways). Maximum speed was only about 250 mph due to the low thrust of the single cruise engine. Pilot workload was very high during landing, just when pilot attention was most important. The lift engines had to be started as late as possible, due to the high combined fuel consumption of the five engines. The ignition procedure was very labor intensive, as was transition from wing-borne to jet-borne flight. The second test aircraft crashed on 2 October 1963 due to a controls malfunction, killing the pilot. It was rebuilt and the two aircraft continued to fly until 1967.
28. Dassault Balzac V
Although there was no British requirement for the RB.108 lift engine, Dassault in France was interested in developing a supersonic vertical take-off and landing fighter. The first step was to take eight of the existing RB.108 lift engines and install them in the Mirage III prototype airframe 001. The rebuilt aircraft, nicknamed Balzac, weighed about 13,500 lbs. It had a fattened and stretched fuselage (43 ft), but the same 24 ft span wings. The inlet duct for the cruise engine, the 4,850 lb thrust Bristol Orpheus, ran down the center of the lift engine collection. The front four engines were also separated from their rear counterparts by the main landing gear to balance the center of gravity. Each lift engine pair shared an inlet door and an exhaust door. First tethered hover was performed on 12 October 1962, with the first free hover made 6 days later. First conventional flight was made on 1 March 1963. During transition, all the lift engine doors created quite a bit of drag. On 27 January 1964, during one of the first transition attempts, it crashed in a "falling leaf" accident, killing the pilot. It was rebuilt and killed another pilot on 8 September 1965; this time it was beyond repair.
29. Dassault Mirage III-V
The III-V (V for "vertical") was a Mirage III airframe, modified with eight RB.162-31 lift engines (generating 5,400 lb thrust each, or 16:1 thrust to weight!), long-stroke landing gears, and various doors to minimize the undesirable effects of the lift engine exhausts. It was 59 ft long, with a 29 ft wingspan, and weighed about 30,000 lb. It was powered by a SNECMA TF-104 (12,000 lb thrust dry, 20,000 lb in afterburner). Control power was improved over the Balzac, with similarly located control jets at the nose, tail and wingtips. First hover was achieved on 12 February 1965. The TF-104 was upgraded to a TF-106 for the first supersonic flight. First transition was conducted in March 1966. The second aircraft was fitted with a 10,750 lb thrust Pratt & Whitney TF30. It is the fastest V/STOL aircraft on record, achieving Mach 2.04 on 12 September 1966. The eight engines didn't leave much room for fuel and a visiting US Air Force pilot had to eject, destroying one of the two aircraft when he ran out of fuel during low-speed and hover operations. The other III-V was also lost. With the entire fuselage filled with lift engines, the Balzac and the III-V seemed to prove that with enough lift engines, any aircraft could be converted to V/STOL. The problem, however, was that there was no room for anything else. The Mirage III-V weighed about 3,000 lb over the basic Mirage III, which cost about half the payload and fuel.
Same Propulsion System for Hover and Forward Flight (Aircraft # 1 - 26)
Separate Power Plant for Hover (Aircraft # 27 - 29)
Combined Power Plant for Hover (Aircraft # 30 - 37)
Augmented Power Plant for Hover (Aircraft # 38 - 45)
Vision For the Future (and Credits, etc)
V/STOL Aircraft and Propulsion Concepts (The V/STOL "Wheel of Misfortune")
(c) 1997 American Helicopter Society