Why a Duct?

At A Glance


Flight vehicles must be concerned with the three axes - pitch, yaw and roll.

Historically pitch has been the most difficult axis to control for ducted fan vehicles. Generally as the speed of the vehicle increases there is a tendency for the vehicle to "pitch-up", or tilt back. This has created a barrier to forward speed in excess of about 8 knots.

We have successfully developed a flight dynamics model, again a combination of duct and fan, coupled with a fly-by-wire system, which provides control in all three axes.


Why a Duct?


Trek Aerospace has successfully designed, developed and tested a combination of power plant, drive train and ducted fans, which are able to deliver significantly more thrust than the combined package weight. Testing of this "core technology" took place in a wind tunnel at NASA-Ames Research Center in Mountain View, California in 2000. A full-scale model of the duct and fan configuration was tested with impressive results. We then built a full-scale POC (proof-of-concept) manned prototype, known as SoloTrek™. This craft achieved over seventy individual manned flights during high-power ground and flight-testing. The first controlled tethered manned test flight of the POC prototype aircraft was successfully achieved on December 18, 2001.

Core Technology

The core technology, around which we have designed our products, looks deceptively simple. It consists of a set of counter-rotating fans, inside a set of ducts, attached to a central gearbox and drive train, and then to a power plant. Our proprietary advantage is that we know the proper combinations of these items, and have developed the software which operates the computerized fly by wire system, which makes this combination of items able to deliver the power and control necessary for this genre of powered-lift vehicle to fly.

Ducted Fan Definition

In aviation, “ducted-fan” and “shrouded-prop” are terms frequently used interchangeably.  Generally speaking, a “duct” has a length that is at least as long as its diameter.  Shorter “ducts” are considered “shrouds”.  Similarly, a “fan” generally has five or more blades, whereas a “prop” has four or less blades.  Technically, what Trek designs and builds are “shrouded-props”.

The shape of the duct and its mated fans is critical for optimal performance. It is our advanced proprietary CFD model, which allows us to develop the optimal combination for nearly any application. We have designed ducts with weight as one of the primary concerns. We have been able to build ducts from composite materials with extremely tight tolerances to produce the proper combination for optimal thrust.

Control System

We have developed a computerized fly-by-wire system which has been fully tested on Springtail.  This proprietary onboard computer hardware and software helps to ensure maximum craft performance and pilot safety.  Three-axis directional control is achieved through vanes which are mounted in the ducts.  Depending on the application, the duct and fans can be rotated for additional control.  We have also integrated a three-axis gyro for applications where control on all three axes is necessary.  Because the system is computer controlled, advanced attributes such as a built-in GPS guidance control, a collision avoidance system, and position, altitude and direction feedback are all possible.

Drive Train

A premium quality drive train is critical to assure peak transfer of power from the engine.  It's this component of the aircraft that will convert horsepower from the power plant into smooth and strong motion necessary to obtain flight.  The wrong drive train will weaken the entire performance of your aircraft.  We have developed a unique drive train that employs several different materials to deliver a lightweight system of gears, universal joints, drive shafts, and gearboxes, which effectively and efficiently transfer power to the fans.

Power Plant

We have spent a great deal of time and effort to determine the proper power plant to include in our core technology package.  There are many options to choose from; reciprocating (both aircraft and automotive derivatives), turbine, micro/mini turbine, micro/mini free piston, and rotary power plants.  Our power plant choice for Springtail and Dragonfly is a proprietary rotary engine we developed together with our engine manufacturer.  It has the proper combination of characteristics which, when coupled with the attributes of our core technology, produces a power delivery system that is efficient and successful.



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