| T38 | |
|---|---|
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| The McDonnell XF-88B with a T38 turboprop in the nose | |
| Type | Turboshaft |
| National origin | United States |
| Manufacturer | Allison Engine Company |
| Major applications | CV-240-21 Turboliner McDonnell XF-88B |
| Variants | Allison T40 |
| Developed into | Allison T56 |
TheAllison T38 (company Model501) was an early turboprop engine developed byAllison Engine Company during the late 1940s. The T38 became the basis for the very successful family ofAllison T56 turboprop engine.[1]
Developed as a stand-alone single section of theT40 (Model 500) twin engine to aid in development of the T40, 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.[2]
Initially rated at 2,000 shp (1,500 kW) the T38 first ran in 1947 and flew in the nose of aBoeing B-17 Flying Fortress test-bed on 19 April 1949, rated at 2,250 shp (1,680 kW). Problems with gearbox vibration and combustion were dealt with during the test program and were mirrored by problems with theT40, which had a pair of T38 power sections feeding a common gearbox. The engines fitted to theConvair CV-240-21 Turboliner were rated to 2,750 shp (2,050 kW) equivalent.[2]
In 1951, theUnited States Air Force decided that the production version of theBeechcraft XT-36 trainer—then in themockup stage and designed for thePratt & Whitney R-2800—would be retrofitted with the T38 when the engine entered full-scale production, which was anticipated to occur in 1955–1960. This decision ultimately doomed the aircraft, as the design changes required to accommodate the T38 delayed the project and rendered the aircraft overweight and over budget.[3]
Although the only other aircraft slated to receive the T38 as a production engine, theConvair T-29E, was cancelled, the T38 did power a convertedConvair CV-240 (the CV-240-21 Turboliner, a project that would be abandoned due to engine problems), and was fitted in the nose of theMcDonnell 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 theAllison T56/Model 501 and the projectedAllison T39.[2]
Data from Aircraft engines of the World 1953[4]
Related development
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