GRADUATING TO THE SR.53

When I joined SARO from the RAF in 1948, as a Flight Engineer qualified on the Mk V Sunderland, my first task was to “activate” the powered Flying Control Test-bed Sunderland on loan to SARO.  The learning curve was steep since we were pioneering an extremely new concept of flying control surfaces based on a WWII gun turret developed by Boulton-Paul Ltd.

I then flew as Chief Flight Engineer on the SARO “Princess” ten-propeller turbine Flying Boat.  When test flying ceased on 5^th May 1954 – after 46 flights – 100 hours, I wondered what I would do next.  To my amazement, I was appointed Chief Development Engineer, SR.53; with a view to setting up a SARO Flight Test Unit at the Aircraft and Experimental Establishment at Boscombe Down (the Isle of Wight was too small!)

We formed a team of three, myself, a D.O. representative and a Works Supervisor, in order to schedule, design or procure every aspect of equipment necessary to maintain and operate the SR.53.  The list covered everything from special tools to HTP Tankers (Designed and manufactured by SARO Anglesey)

On re0assembling the SR.53 in our dedicated hangar at AAEE, we began a comprehensive ground teat programme.  The HTP system, containing some 640 gallons in 5 plastic lined tanks in the belly of the SR.53 was filled with well filtered hydrant water and then discharged through a 3” feeder at 8 psi on to the hangar floor.  The process was stop-watched.

Then came the day when the first filling with 98% HTP (H2O2) took place and all components in the system worked correctly.

The HTP tanks, as well as the kerosene tanks in the wings and below the cockpit floor were pressurised to 8 psi from spherical steel bottles pressurised to 4000 psi.  In our hangar we bottled oil and moisture free air at 6000 psi into mobile trolleys.

The SR.53 hydraulic system functioned at 4000 psi.

After ground testing of the Armstrong Siddeley “Viper” gas-turbine (1,600 lbs thrust), and the DeHavilland “Spectre” Rocket motor (7,200 lb thrust) – derated from 8000 lbs, John Booth made the first Test Flight in May 1957.  Two SR.53s were operated but never did we have 2 Spectre Rocket Motors at the same time!  Test flying was terminated in 1960 after SARO had been acquired by Westland. 

The SR.53 achieved a Rate of Climb of 29,000 ft/min and a Mach no. of 1.33

Dick Stratton

January 2005

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