Five Engine Bombers ...

[Mark Allen M]

... or better known as "engine test beds".

Wiki: The T38 started life with a 19-stage axial compressor, eight can type combustion chambers, a 4-stage turbine driving the compressor and the extension shaft to the reduction gearbox.

Initially rated at 2,000 shp (1,491.40 kW) the T38 first ran in 1947 and flew in the nose of a Boeing B-17 Flying Fortress test-bed on 19 April 1949, rated at 2,250 shp (1,677.82 kW). Problems with gearbox vibration and combustion were dealt with during the test programme and were mirrored by problems in the Allison T40 programme. The engines fitted to the Convair CV-240-21 Turboliner were rated to 2,750shp.

Although the only aircraft slated to receive the T38 as a production engine, the Convair T-29E, was cancelled, the T38 did power a converted Convair CV-240 (the CV-240-21 Turboliner, a project that would be abandoned due to engine problems), and was fitted in the nose of the McDonnell XF-88B to drive experimental supersonic propellers. Further development of the T38 provided the power sections for the Allison T40 as well as forming the basis for the Allison T56/Model 501 and the projected Allison T39

The Allison T38 (company Model 501) was an early large turboprop engine developed by Allison Engine Company during the late 1940s. The T38 became the basis for the very successful family of Allison T56 turboprop engine.


Lockheed built B-17G with Allison T-38 engine, January 1955. A B-17G with nose section removed and replaced with a strengthened mount for a fifth engine.
This Lockheed/Vega B-17G-105-VE Fortress 44-85747 was loaned to the Navy as BuNo 83999 for engine testbed work.


Lockheed built B-17G with Allison T-38 engine, January 1955.


Lockheed built B-17G with Allison T-38 engine, January 1955.


B-17G as test-bed for Allison T-56 turboprop engine, ca. 1956.


B-17G as test-bed for Allison T-56 turboprop engine, ca. 1956.


B-17 Flying Fortress test bed for the P&W T-34 turboprop engine. Later flown on airshow circuits as "Liberty Belle".

Wiki: The Pratt & Whitney T34 (company designation PT2) was an axial flow turboprop engine designed and built by Pratt & Whitney. Its model name was Turbo-Wasp.
In 1945 the United States Navy funded the development of a turboprop engine. The T34 was produced from 1951 to 1960, but never used in U.S. Navy aircraft production.

The YT34 engine with three wide-bladed propellers was made for two Navy Lockheed R7V-2 Constellation(C-121s) variants, for testing. Flight tests were on 1 September 1954.

In September 1950, a testbed Boeing B-17 Flying Fortress flew with a T34 turboprop mounted in the nose of the bomber. The first application for the T34 was the Boeing YC-97J Stratofreighter, which later became the Aero Spacelines Super Guppy. The next application for the engine was the Douglas C-133 Cargomaster.

[Mark Allen M]

Lancaster (NG465) Rolls Royce engine flying test bed, Hucknall, 1949.


Armstrong Whitworth-built Lancaster modified to B.VI and used by Rolls Royce for flight testing the Dart turboprop in a nose installation. Retired in 1952.


Avro 683 Lancaster B.VI ND784 Armstrong Siddeley Mamba turboprop test in nose, c 1950.


AVRO 683 LANCASTER GRIII, SW342 Mamba installation in the nose, and either Adder or Viper in the tail.


Avro 694 Lincoln B.2 G-37-1 Rolls Royce Tyne turboprop test in nose, ex RF530 with Napier Naiad in nose, 1956-57.


Avro 694 Lincoln B.2 G-37-1 Rolls Royce Tyne turboprop test in nose, ex RF530 with Napier Naiad in nose, 1956-57.

[Mark Allen M]

Boeing (Lockheed-Vega) B-17G-110-VE Fortress 44-85813 c/n 8722
converted at Boeing Wichita 4-46 for Wright to test 5000hp XT-35 'Typhoon' turbo 1948.

Converted to EB-17G turboprop test bed by Curtiss Wright. Designation changed to JB-17G in 1956. Sold to Curtiss Wright in 1957 under civil number N6694C. Went through succession of civilian owners, ultimately ending up as aerial tanker. Crashed on takeoff Apr 16, 1980 from Bear Pen Airport, North Carolina. Crash remains eventually acquired by Tom Reilly of Kissimmee, FL for use in creating a flyable B-17 out of usable parts from this plane and from 44-85734. Reported in 2006 to be under restoration to fly at Douglas, GA. Registered N3154S Feb 26, 2007. Parts from crashed 44-85505 used for restoration. In 2012 was at Champaign Aviation Museum, Urbana, Ohio and under restoration.

[Rick65]

Fascinating.
And I thought you were going to offer the He 111Z

[Mark Allen M]

Three B-17G's converted to engine test beds. The nose section was removed and replaced with a strengthened mount for a fifth engine. The Pratt & Whitney XT-34, Wright XT-35, Wright R-3350 and Allison T-56 engines were all flight tested on JB-17Gs.

[JohnB]

Don't forget the B-29 with its APU....so technically all B-29s had 5 engines.
also the XB-29G was used as a jet testbed with GE engines mounted under the bomb bay.
Vulcan engine testbed for the Concorde.

[jmkendall]

The Boeing testbed that is now at Urbana was testing the engine that was originally being considered for the B-52. I'm not sure how well known it is that Boeing was either originally designing the B-52 with a turbo engine, or had one as a back up, but there it is.

[quemerford]

The B-45 would also qualify: used for various bomb-bay mounted engine tests.

[JohnB]

I'm not sure how well known it is that Boeing was either originally designing the B-52 with a turbo engine, or had one as a back up...

You're correct. The early paper studies for the B-52 were for a swept wing turboprop since it was thought at the time that jets would preclude long range aircraft because of their fuel consumption. I don't believe any metal was cut for the airframe.

And while we're on the subject of extra engines stuck on noses, remember there was a C-124 with a huge turboprop in its nose, a testbed for the engine in the projected Douglas C-132.

[phil65]

Liberty Belle at NEAM, 1985ish...

Phil

[Joe Scheil]

The 111Z!

Attachments

[Clifford Bossie]

Don't forget the B-29 with its APU....so technically all B-29s had 5 engines.
also the XB-29G was used as a jet testbed with GE engines mounted under the bomb bay.
Vulcan engine testbed for the Concorde.

Does that make a B727 a four engined airplane?

[avenger2504]

Interesting to see the B17 that had the Typhoon turbo prop also had electric props on the Wright Cyclones.

[Mark Allen M]

Yes technically there were at least two B-29's with five engines.

Bell-built B-29 (44-24043) was modified as a testbed for General Electric jet engines and redesignated XB-29G. The engine was mounted on a cradle in the bomb bay which could be extended below the aircraft to test its operation in a fast airstream.





Below Boeing B-29-96-BW Superfortress 45-21808 Delivered to USAAF 24 Aug 1945. Assigned to NACA Aircraft Engine Research Laboratory, Lewis Field, Cleveland, OH Apr 1946 to Oct 1948 Code BF-808. Used as a flying testbed for turbojet and ramjet engines. The engines were mounted under the fuselage and operated in flight conditions. Ramjet-powered missiles were also launched from the aircraft. Registered NACA 266. Last reported at Boeing, Seattle, WA 12 May 1954.

[k5083]

Here is a 3-engine bomber, but it counts as a "one extra" test bed.

The French used leftover wartime B-26 43-34584 (a close sister to 43-34581, which the NMUSAF obtained from France) to test their Atar jet engine, which became the key engine for a generation of Dassault and other fighters. It was demonstrated at the 1951 Paris airshow with both props feathered.



Of course there was also Canada's 5-engine B-47.



August