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.

Sources:


  1. American Combat Planes, Third Enlarged Edition, Ray Wagner, Doubleday, 1982.

  2. Post World War II Bombers, Marcelle Size Knaack, Office of Air Force History, 1988.

  3. The Boeing B-47, Peter Bowers, Aircraft in Profile, Doubleday, 1968.

  4. Boeing Aircraft Since 1916, Peter M. Bowers, Naval Institute Press, 1989.

  5. United States Military Aircraft Since 1909, Gordon Swanborough and Peter M. Bowers, Smithsonian, 1989.

  6. Avro Arrow, The Arrowheads, Boston Mills Press, 1992.

  7. Boeing B-47 Stratojet--Variant Briefing. Bill Yenne, International Air Power Review, Vol 6, 2002.