John Scott-Scott


John Scott-Scott, or ‘Scotty’ as many knew him, died in the early hours of Saturday 12th December 2015. This marked the passing of a truly remarkable aerospace engineer, forged by Britain’s military demands post-World War Two and in the subsequent Cold War years.

John’s speciality was hydrodynamics, in particular of high performance centrifugal pumps for rocket engines, for which he gained World renown. However, his broader expertise encompassed space launchers; aircraft; road vehicles and surface ships, and any form of propulsion relating to them. John was equally at home with analysis, building test rigs or hands-on work with actual engines and indeed had his own workshop in which he manufactured model aircraft engines, scientific equipment and components for test rigs to very tight tolerances. He made little distinction between work time and leisure time when it came to engineering; it was all the same to him. John’s aviation interests led him first to become a glider pilot when he was 14. He then flew Tiger Moths when he was 15/16 and went on to gain a private pilot’s license. He eventually became a Flight Lieutenant in 637 Squadron.

John was born in Doncaster and grew up there with his Mother, who was widowed when John was only 8 years old. John developed a strong interest in rockets and as a teenager he built many of his own, which is remarkable, for although there had been a ‘buzz in the air’ about spaceflight from the decade before the war, the practical art was still very new post-war.
John would have been in his mid-teens when he started distilling his own hydrogen peroxide, a propellant which was his favourite throughout his career. He must have felt completely at home in an industry which had settled on this oxidiser (then called HTP) for propelling mixed powerplant aircraft, the Blue Steel stand-off weapon, the Black Knight re-entry vehicle launcher and, later, the Black Arrow launcher.

John left Doncaster at 18 to attend Aston University and study Engineering. On leaving University in 1955, John did two things; married Pauline Cullen and got a job with Armstrong Siddeley at Ansty, near Coventry. John’s career took him through the merger of various aircraft companies. Armstrong Siddeley became Bristol Siddeley in 1958, and finally Rolls-Royce in 1967, all on the site at Ansty. John rose rapidly within the Company becoming Head of Hydrodynamic Research.

By the mid-1960s John was pioneering research on super-cavitating pumps (sometimes called vapour core pumps) in which the fluid forms a stable bubble at the pump inlet and the liquid forms a thin film travelling at the outer edge of the inducer blade until the bubble closes in a controlled manner in a high pressure region inside the pump impeller. This type of pump enables very low supply tank pressures and high pump delivery pressure to be achieved. Sadly, due to the loss of the rocket programmes in the UK, this technology has remained largely undeveloped.

The work also showed promise for pump-jet propulsion on ships and John had an extensive period of research with the Admiralty exploring this possibility, including sea trials.
John’s work through the 1955-1972 period enabled him to contribute to all of the major British rocket projects, for apart from the HTP-powered vehicles, the merger with Rolls-Royce brought the liquid oxygen-based engines for Blue Streak to Ansty.

Following the closure of the Rolls-Royce rocket department in 1972, John moved to work on industrial and marine gas turbines. In 1982 he, Alan Bond (then UKAEA) and Bob Parkinson (then British Aerospace) met up informally to discuss a different kind of engine which eventually led to the HOTOL project. This was a combined air-breathing and rocket engine, employing air pre-cooling to allow Mach 5 to be reached while air-breathing before transition to rocket mode to reach orbit. It became the basis of a concept to enable an aircraft to fly into space and return without expending hardware. John was immediately a strong supporter of the concept. He had the correct combination of knowledge and skills to assess the feasibility of the idea and conclude that, though difficult, it should work.

John laboured tirelessly within Rolls-Royce, often against strong opposition, to secure funding and build support. Bob did the same within British Aerospace and finally in 1987 the HOTOL project was born as a 50:50 industry/Government funded study.

John ran the test programme at Ansty to demonstrate the feasibility of the engine pre-cooler. This consisted of a cryogenic wind tunnel driven by an Avon gas turbine with extensive cryogenic facilities to achieve temperatures down to -100°C. A central issue was to find ways to combat frost formation and a technique was eventually found, through cryogenic injection, to drop the air temperature below -50°C at which the frost does not stick to cold surfaces. John also managed the engine design activities at Ansty and R-R Bristol and coordinated the R-R activities with BAe Warton and Stevenage to meet the requirements of the vehicle.

The UK is, however, a fickle place to do technology and despite promising results (and lots of problems!) the Project came to a halt in 1989.

In order not to lose the technology gained in the 1980s, John, Alan and Richard Varvill (who had been in the Advanced Projects Office at R-R working on the engine design) formed their own company, Reaction Engines Ltd.

Throughout the 1990s the Company evolved the HOTOL work into the Skylon vehicle and the SABRE engines. The three founders made countless approaches to industry, the European Space Agency and the British Government for support, but with only limited success. They progressed the design using their own resources and eventually attracted some private investment towards the end of the 1990s. However, in the early 2000s a larger investor, Paul Portelli, took interest. John and Paul got on very well because Paul was an aviation enthusiast rebuilding a rescued Spitfire and John, being a pilot, found they had a lot in common.

John played a large role in building the first Reaction Engines wind tunnel, which was later expanded to a cryogenic tunnel, to begin development of a much more efficient frost control system than had been possible for HOTOL. The success of this work led to further private investment from Nigel McNair-Scott, and to the construction of the Company’s B9 test site at the Culham Science Centre in Oxfordshire in 2005. This was something John could really get his teeth into since it involved employing a Viper jet engine fitted with a precooler and a modified fuel system to operate at cryogenic conditions. John led the team carrying out the engine modifications. In 2012 this facility demonstrated successful frost control down to -130°C, paving the way for the future of precooled engines.

John was a very likeable character with a slightly wicked sense of humour. On a visit to Warton in the HOTOL days John showed Richard Varvill what it was like being fluid in a centrifugal pump when he caught Richard in the rotating door to the design block and centrifuged him! John’s driving was legendary, and many ‘white knuckled’ passengers experienced the ‘thrill’ as they closed with oncoming vehicles on the wrong side of the road at around 200mph, most of it on John’s clock!

In later years, John became President of the Rolls-Royce Heritage Society which aims to preserve examples of as many different types of aero and rocket engines as possible. Many ex-RR people have willingly donated their effort to the preservation and restoration of this hardware, which now forms a very impressive collection in Derby.

Amongst all of his tremendous commitment to propulsion engineering, John and Pauline found the time raise a family; Jane, Elizabeth and Mark. When they grew up, Jane and Elizabeth went into education and Mark into the aerospace industry. Sadly, Pauline died in 2014.

As with many of Britain’s engineers from this period, John’s direct legacy is hard to assess because of the historical abandonment of British high technology research and development; a gross failure to build on the UK’s world leading technical achievements.

However, Reaction Engines, which owes so much to John’s tireless work, continues and has, at last, enjoyed recognition by both Government and industry through strong partnerships with BAE Systems, its old associate from the HOTOL project, and the UK Space Agency. This success is a tribute to John, his incredible abilities and his perseverance.