1. The HTT-40 will be an all-metal tandem seat aircraft powered by a 1,100 hp (820 kW) turboprop engine.

2. The inventive turboprop engine consists of a power jet which is mounted coaxially to the engine axis (X-X'), comprises a fan case and a gas ejecting system provided with two afterbody half-cowlings (10b) each of which is pivotable around an axis (A2) between open and closed positions, wherein said half-cowlings are connected to the downstream of said fan case through a 'V-blade/V-groove' system.