In a week that has seen the first F-35Bs land vertically on the Queen Elizabeth carrier, The Engineer remembers a slightly less advanced VTOL aircraft in the shape of Rolls-Royce’s flying bedstead.
Also known as the vertical flight research rig or the Thrust Measurement Rig (TMR) – the zany contraption first appeared in these pages 64 years ago this week, having made its maiden, free flight on August 3rd 1954. The same issue featured a vignette on Lockheed’s XFV-1, a vertically launched fighter aircraft developed for the US Navy. According to our predecessors, technology had only just matured to the point where VTOL flight was becoming a reality, powered primarily by the advent of the jet engine.
“The prospect of launching an aircraft vertically using only the engines provided for its level flight requirements, has been brought much nearer reality in recent years by the rapid evolution of the gas turbine,” The Engineer wrote. “Since the Whittle ‘W.1’ engine of less than 1,000lb thrust, the specific thrust has been raised from about 1.5lb per pound weight to that of nearly 4lb per pound weight in the latest turbo-jet engine in the 10,000/15,000lb thrust category. These increases have also been achieved without diametral growth. An aircraft with two such engines mounted in the fuselage, could therefore be designed with sufficient thrust to accelerate vertically from rest.”
Whereas the American XFV-1 used counter-rotating propellers powered by twin gas turbines to generate its vertical lift, the UK research rig applied techniques more akin to the F-35B’s V/STOL capability. Its two Rolls-Royce “Nene” turbojet engines – each producing around 500lb of thrust – were mounted horizontally within a steel frame, but the jets were ducted through 90 degrees so that the thrust was directed vertically downward. This vectored thrust was described by The Engineer as “a favourable arrangement for balancing the device and eliminates gyroscopic effect.”
The framework sat upon four legs that used castors for wheels, with the pilot perched on a platform above the two engines, using a conventional control column and rudder bar to steer the vehicle with jets of compressed air from nozzles in the cross-arms. It sounds like a fairly rudimentary control system and certainly not one for the faint-hearted. In fact, the sole purpose of the research rig was to investigate the issues around controlling a VTOL craft, and initial tests saw the flying bedstead tethered to the ground in an effort to enhance both pilot and machine safety. The August 3rd flight marked the first time the TMR was allowed to fly untethered, described below:
“It remained airborne for nearly ten minutes and during this time it moved about over the ground under the pilot’s control at heights of from 5ft to 10ft, returning finally to alight at its starting point. For subsequent flight it has been flown free at heights up to 25ft.”
Vectored thrust VTOL aircraft have of course evolved significantly since the days of the flying bedstead, most famously perhaps with the Harrier Jump Jet. The Harrier, in various guises, has been in continuous service since the 1960s and is considered the only truly successful V/STOL to emerge from that era, despite being limited to subsonic airspeeds. Its natural successor, the F-35B, is capable of speeds in excess of Mach 1.6, but requires a short ski-slope to launch from carriers before landing vertically. The UK has publicly committed to buying 138 F-35Bs, though so far just 15 have been delivered.
Goodness me does this invoke yet more concern over the aircraft industry that was given away by politicians over the years. The flying bedstead as stated flying in 1954 and just 5 years later Bill Bedford fly’s the first P1127 just 4 years later. We at that time do doubt with Sydney Camms vision were planning a supersonic version that in 1964 was cancelled by a Labour government because the thought was we would not need pilots in the future and the Americans did not have anything like it. Just think where our aircraft industry could have been with political support for our brilliant engineers of that time. I found whilst staying in the Brownsover hall hotel where Frank Whittle had his office the following quote from a government military/technical expert official that had turned down his proposal ” this jet engine will never power an aircraft as it is too heavy and the materials fail” Whittle had written a comment alongside it some time later as follows ” how fortunate for the country that I was too stupid to know this” maybe now we need a government led push to support our engineers once again and let them show the bean counters that prosperity starts with conceptualising, designing, developing and making things that can be sold. What Bank can do that? It is too late for me so I say to todays engineers get out there and do it despite a lack of political support.
Ah! Pre EU days. 😉
Somewhere in the depths of my memory is a recollection that in the late 50s (early 60s?) the Short SR1 literally flew itself into the ground: the error finally being assessed as some calculation for its control mechanism that was ‘out’ by a factor of 10: come to think of it, it must have been early 60s and a lecturer told us of the importance of doing a ‘rough’ calculation before finally committing to slide-rule.