Naval Officer Lt. Charles Dennistoun Burney had the original idea of a seaplane that would use hydrofoils rather than floats to provide support when on the water with the supporting struts for the hydrofoils being termed ‘hydropeds’. Burney lack the resources to develop his ideas and so the entered into a relatively secret arrangement with the British and Colonial Aeroplane Company. The Admiralty had unofficially promised further support and so a separate office was set up, known to just a handful of people as the X Department. Frank Barnwell headed the Design Team with Clifford Tinson as his assistant.
Their first proposal delightfully codenamed X-1 was an adaption of the Bristol GE.1 It featured a watertight hull and wing tip floats provided to support buoyancy whilst at rest. The craft could be accelerated using water propellers which disengaged when the machine achieved flight using the main engine to drive a conventional airscrew for take-off. After a number of investigations and alterations the proposal was abandoned.
Barnwell then designed and built two machines (X.2 and X.3) both being strikingly clean monoplanes.
X.2 used an 80 hp Canton Unné radial engine, which was fitted with a clutch arrangement to allow the water propellers or the main air propeller to be engaged. Initial tests took place at Dale, Milford Haven from 9th May 1912 and initially the results were encouraging although a number of issues were identified, mainly relating to vibration.
The machine was towed behind a torpedo boat which in itself created stability issues although these decreased due to changes in the parafoil lifting planes and the addition of a controllable water elevator.
In December 1912, trials were carried out with the engine removed and replaced with 500lbs of ballast.
During one test run the aircraft lifted off at 30 knots although unfortunately the hydrofoils had sustained damage and it went nose-high, stalled and slide slipped into a crash. Thankfully Pilot George Dacre emerged uninjured.
The X.2 was not repaired although in March 1913 the Admiralty funded a second machine, X.3 (given a build no 159) and which was of larger dimensions and fitted with a 200 hp Canton Unné engine.
Taxying trials (initially with an 80hp Gnome engine and dummy outriggers fitted instead of lifting wings) took place at Dale in August 1913. These trials were promising in terms of taxying performance and stability under tow.
In June 1914, the aircraft was prepared for flight trials (using the Canton Unné engine) when unfortunately it was seriously damaged after it ran aground on a submerged sandbank. With finances being eaten up by the war effort, the secret project came to an end.
Burney utilised the knowledge he had gained and turned his attention to developing the Mine-Sweeping Paravane at HMS Vernon during 1915.
|Powerplant||80 hp Canton Unné||200 hp Canton Unné|
|Span||55 ft 9 in||57 ft 10 in|
|Capacity||Two crew||Two crew|
Variants and number built
Two experimental prototypes only: X.2 (Bristol build number 92) and X.3 (build number 159).
No examples survive