Tag Archives: April 1st

English Electric / Avro Canada Canberra T.25 “Hoverberra”

Canada flagUK flag Canada / United Kingdom (1960)
Experimental VTOL Aircraft Variant – 1 Converted

The prototype Canberra T.25 during it’s first vertical flight. The Avro-Stroker B.69-420 jet engines would explode and destroy the plane just seconds after this photo was taken. (British Archives)

The English Electric Canberra T.25 (nicknamed Hoverberra by the designer team) was an experimental VTOL variant of the British Canberra jet bomber which was patented and developed by Avro Canada designer Richard Stroker. With a standard Canberra B.2 converted to mount two experimental Avro-Stroker BS.69-420 turbojet engines, the aircraft was given the experimental title of T.25 and was vertically flown for the first time on April 1st of 1960. Unfortunately, the first and only test flight resulted in catastrophic failure when the two experimental Avro-Stroker J-69-420 engines spontaneously combusted and exploded shortly after the T.25 got off the ground. Soon after, all work on the project was halted.

History

In the recent months, an experimental variant of the English Electric Canberra jet bomber was discovered in the National Archives in Greater London. Surprisingly enough, the variant was developed in the Dominion of Canada, which never officially operated or received any Canberras! This experimental variant bears the title of Canberra T.25 and was a testbed for an obscure Canadian developed turbojet engine designated as the “Avro-Stroker BS.69-420”. Much of the information regarding this variant has been lost to history, but the fundamentals appear to have been recorded by a variety of sources. Although Canada was never a recipient or official operator of the English Electric Canberra jet bomber, a single example of the Canberra B.2 found its way to Canada in February of 1959. Details of this purchase are not known, but it would appear that the aircraft was purchased by a civilian firm. As such, the aircraft was stripped of much of its military equipment.

Sometime in late 1959, a relatively unknown Avro Canada employee known by the name of Richard Stroker (referred as “Dick” by most) patented a turbojet engine which he had been working on since 1951. Stroker was part of the occupational forces in Germany after the war, and he was one of the engineers who were tasked with studying experimental Nazi hoverjet technology. Details on the precise technologies he was tasked to study are unclear. It would appear that the Avro Canada had taken an interest in this experimental engine Stroker developed, and decided to manufacture a small batch for trials. The engine received the designation of “Avro-Stroker BS.69-420” and it would appear that only four examples were manufactured. Wishing to test the engines, Avro Canada reached out to the Canadian government for permission to utilize a test frame. With the rather small size of the turbojet engines, they were envisioned to power the aircraft horizontally, allowing it to lift upwards. Previous work done on the VZ-9 Avrocar assisted with this engine’s development. As the Canberra B.2 was obtained recently, the Canadian government allocated it to the Avro Canada designers. It would appear that the British Ministry of Aviation was notified of this development, and they took a keen interest in the modification. Soon after, a team of twelve British engineers were dispatched to Canada to observe and assist in the project’s development.

By March 3rd of 1960, much of the modified Canberra’s design was completed. The Canberra received the official designation of Canberra T.25 within the United Kingdom and was nicknamed “Hoverberra” by the design team. Two BS.69-420 turbojet engines were mounted within the bomb bay and rear fuselage at a 90-degree angle. According to official engine bench tests, the BS.69-420 was capable of producing 4410 lb (2,000 kg) of thrust, which would have barely been able to power the Canberra, even with most of its military equipment stripped. As such, the Canberra T.25 was transported to the Toronto Malton Airport (today known as Pearson International Airport) on March 27th. Preparations were being made to initiate the Canberra T.25’s first vertical flight. The Canadian test pilot’s full name is unknown, but documents identified him as “Pranks.” Soon after, all preparations for the Canberra T.25’s first flight was complete. The test flight was to take place within a hangar, as the maiden flight’s purpose was to see if the aircraft could get off the ground at all, and did not instruct the pilot to fly high.

On April 1st at 0500 hours exact, the two BS.69-420 turbojet engines were ignited and the Canberra T.25 slowly lifted itself into the air. Canadian and British engineers and designers observed this process at a safe distance. Twelve seconds after the aircraft began hovering, a strange sound was reported by Pranks which he described as “a high pitched screeching.” As this was unusual and did not occur during engine bench tests, Pranks was ordered to immediately shut down the engine and descend. Just as this command was spoken, the B.69-420 turbojet engines exploded which completely destroyed the Canberra T.25 and killed Pranks. Two nearby engineers were also injured by flaming debris, one was severely burnt while the other made it off with relatively light injuries. Soon after this tragic incident, the Canadian government ordered the immediate cessation of work on this project.

As not much documentation seems to exist on this obscure project, much of the developmental history and post-cancellation history is unknown. However, the Canberra T.25 “Hoverberra” holds a special spot in aviation history as Canada’s indigenous endeavor to produce a VTOL aircraft. It is recorded that Richard Stroker soon resigned from Avro Canada following the catastrophic disaster. He soon moved from Toronto to Medicine Hat where he opened up a restaurant with his wife. He died in 1996 after suffering from colonl cancer.

Operators

  • Dominion of Canada – The Avro Canada firm developed the Canberra T.25 with assistance from British engineers. The aircraft would have likely entered service as a photo reconnaissance aircraft
  • United Kingdom – The Ministry of Aviation took great interest in the Canadian VTOL development of the Canberra and provided personnel assistance to the Avro Canada designers. It is unknown whether or not they would have adopted the type for service.

Sources

  • Fiddlesworth, R. (1962). Completely Reliable Report on Jet Aircraft: Ministry of Fictitious Aircraft & Aviation.
  • Realname, J. (1960). April 1st Report on VTOL Technology: The Canberra T.25
  • Stroker, R. (1959). Engine Patent: VTOL BS.69-420 Turbojet