Frequently Asked Questions about Airjet

No.  The propulsion system uses a turboshaft engine with direct drive to a dedicated Load Compressor.  The output from the load compressor is not coupled to the fuselage and therefore, there is no torque. 

AirJet has flown a manned proof-of-concept helicopter using a 4-bladed, tip-jet driven rotor that has validated the Technical Viability. See Proof of Concept page.

Various "Hot-Cycle" tip-jet helicopters have been made; however, all were abandoned due to excessive noise levels.  The Djinn was developed, certified and produced by Sud-Ouest Aviation in France.  In fact some one hundred and seventy-five were produced and used as military observation platforms.  The air driven rotor used engine compressor bleed air as its source (not a dedicated load compressor like ours) and consequently their overall cycle efficiency was poor.  AirJet's design optimizes the performance of the helicopter!

NOTAR is a Trade Mark used by MD Helicopters because their helicopters have no tail rotor.  However, the single main rotor is mechanically driven by a gear box and consequently there is torque on the fuselage.  The NOTAR anti-torque system has a large, variable pitch fan in the fuselage providing anti-torque directional control using the coanda effect and a variable direction nozzle at the end of the tail boom.

The AirJet design has no torque on the fuselage and consequently no requirement for an anti-torque system.

This concept does not lend itself to the major OEMs who have an established business model based on the design and spare parts support for transmissions, drive assemblies and tail rotor systems.  AirJet has drastically reduced the number of moving parts required to drive the rotor and maintain Directional Control.  In fact, AirJet's system excluding the gas turbine engine has approximately 5% of the moving parts associated with a mechanically driven helicopter.

a) The overall helicopter efficiency of AirJet's design results in a helicopter with the same payload/range as a mechanically driven Rotor system; however at a lower Maximum Take-off Gross Weight (MTOGW).  This is achieved using the same engine technology (Specific Fuel Consumption, sfc) and comparable structural technology (Not composite vs metal).

b) Due to the significant reduction in the number of rotating and life limited parts, the operating costs are lower.

c) With respect to the twin-engine model, the MTOGW is the same as for the single-engine version.  Both engines have the same power output as the single-engine version. The second engine is set to idle power and in the event of an engine failure will advance to the same set power as the unserviceable engine accelerating within 2-3 seconds to full take-off power (if required).  This provides full mission capability in the event of an engine failure.  The additional weight associated with carrying two full-sized engines is more than compensated for by the weight savings in transmissions, tail rotor, etc.

AirJet firmly believes that our design will be certificated to noise levels certifiable to Stage III and lower noise requirements, surpassing current noise level certifications of conventional helicopters .