CL-52 Flying Testbed For Orenda Turbojet

Last revised January 3, 2003

In spite of the large numbers of B-47s built, none of them ever ended up in the service of foreign air forces. There is, however, one significant exception--a B-47 loaned to the Royal Canadian Air Force as a flying testbed for the Orenda Iroquois turbojet.

In 1956, the USAF loaned B-47B serial number 51-2059 to the Royal Canadian Air Force for use as a flying test bed for the advanced 20,000 lb.s.t. Orenda Iroquois turbojet. A pair of Iroquois engines were to power the projected Avro CF-105 Arrow long-range interceptor, which was currently under development in Canada.

After delivery, the RCAF turned the plane over to Canadair Ltd to complete the required modifications. A separate pod for the test engine was installed on the starboard side of the rear fuselage underneath the horizontal tail. The pod was 30 feet long and about 6 feet in diameter The company assigned its own model number of CL-52 to the project. The CL-52/B-47B flew in RCAF markings, but retained the last three digits of its USAF serial number, which followed the prefix "X" to become the RCAF serial number.

The CL-52 spent a total of 31 hours in the air with the Iroquois engine. Most flights were routine, but on its only full-power flight the Iroquois engine suffered a fan blade failure which damaged the elevator and rudder of the CL-52. The aircraft, however, landed safely.

The first five Arrows (RCAF serials 25201 through 25205) were all powered by Pratt & Whitney J75 turbojets for the initial flight tests. The first Iroquois-powered Arrow was to be number 25206, which was being readied for its first flight when the entire Arrow/Iroquois project was cancelled by the Canadian government on February 20, 1959.

Following cancellation of the Arrow/Iroquois program, all Arrow airframes were ordered to be scrapped, including those in a partially-completed state on the production line. All that survives today is the front end of Arrow 25206 plus a couple of outer wing panels on display at the National Aviation Museum of Ottawa. A pair of Iroquois engines still survive, one in the National Aviation Museum and the other at the Canadian Warplane Heritage Museum in Hamilton, Ontario.

After the termination of the Arrow/Iroquois program, the Iroquois engine was removed from the CL-52 and the aircraft was returned to the USA in August of 1959. The plane was scrapped at Davis Monthan AFB shortly thereafter.


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