02 July 2010

The Adventure of Ducted Fan Flying Machines

Ducted fans can allow for a greater payload and better efficiencies than open propeller systems.
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 Fans

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. _Trek
Logi Aerospace is using the Trek design for ducted fan propulsion, in an attempt to win a lucrative DARPA contract.
The real magic of this vehicle lies in the Shrouded Propellers developed by Trek Aerospace. This is not just an ordinary shroud or nacelle around the propellers. This shroud has been specifically designed to optimize airflow. The result – at takeoff, nearly half the lift is provided by the shroud and not the propellers. This means the propellers cover only half the area of a helicopter and still lift the same amount of vehicle weight.

This also means the propellers are lighter and smaller, so too, are the wings and structures making the vehicle lighter. A lighter vehicle can be flown with a smaller propeller, which makes the wings, the structure and the whole vehicle lighter. It has an iterative effect on the design and scales the vehicle down in size. This scale reduction means our vehicles can often be built for less than half the empty weight, and cost, of other vehicles that don’t have our shroud technology. This also means, that on average, our vehicles have around 1/3 of the propeller area of other vehicles that carry our payload using non-optimized shrouds. This is because our shroud is more efficient and the vehicle at takeoff is lighter. _Logi

The ducted fan design also lends itself to exoskeleton designs for single person flying with light payloads.
The Dragonfly is an imaginative design from Trek.

H/T Brian Wang

DARPA's design specs PDF for their military flying car (50 + pages) via NextBigFuture

It is likely that some version of ducted fan flier will be viable. The versatility and superior safety characteristics of the ducted fan will lend itself to new types of flying machines for a wide variety of tasks. Just as important as the fans, are the engines and drive trains that will be required, as well as the fail-safes.

Ducted fans could easily power hovercraft, ground effect hovercraft, helicopter-type craft, amphibious boat / VTOL planes, and other designs not yet conceived.

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Blogger neil craig said...

The Dragonfly would appear to have an ability only flying cars with enclosed vertical engines have but helicopters don't - namely that they can have a periscope which can project above the the tops of hills & thus allow them to fire wire guided anti-tank missiles while remaining untargetable,

Saturday, 03 July, 2010  

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