The unusual Allison T40 turboprop engine combined two T38 gas turbine power sections that drove a common gearbox (turboprop engines typically have only one gas turbine power section).
A unique version, the XT40-A-1, powered the experimental XF-84H aircraft. While most T40 engines drove contra-rotating propellers, the XF-84’s engine drove a single propeller shaft.
Allison built only two XT40-A-1 engines, and the T40 series was not built in large quantity due to delays and reliability problems. On display are the dual T38 gas turbine power sections from a T40 engine.
TECHNICAL NOTES (XT40-A-1):
Compressor: 19-stage axial flow (in each T38 gas turbine)
Shaft horsepower: 5,332 shp
Jet thrust: 1,296 lbs.
Weight: 2,860 lbs.