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frequently asked questions
The FAQ list is limited to technical questions. For business queries contact peebles@fanwing.com
What are the advantages of FanWing over other forms of flight?
What are the potential uses of the FanWing?
Are there risks/disadvantages?
How much horsepower would an ultralight FanWing need?
Is there vibration of the rotor?
Does the FanWing anticipate vertical take off development?
Is the FanWing vulnerable to turbulence?
The FanWing is slow. Do you anticipate increase in flight speed?
How does the vortex control work?
A series of scaled prototype models have shown controlled and sustained flight. Flights can be seen on Youtube
Patents have been issued in major aircraft-producing countries worldwide, including the US.
Advantages of the FanWing over other forms of powered flight
Fuel economical
Potentially quiet
Predicted wide speed range
Almost instant takeoff and landing
Take-off from unprepared ground, street. rooftop or shipboard
Vertical take-off and landing capability established
No stall
Stable in turbulence
Simple construction with few high-tech material or mechanical requirements
Low maintenance and construction costs
Some obvious applications will be in unmanned surveillance, Ultralight aircraft for sport flying, short-haul freight, fire-fighting, crop-dusting, rescue operations, and city taxi/tourist/police flights. Its potential low sound signature, stability, lightness of construction, slowness and short take-off capability give it potential in both rural and urban applications.
For a full listing of these uses, see applications
There is always in any new technology the risk that R&D will encounter unexpected problems. So far clearly predicted issues are potential ice on the blades, bird or other foreign object damage and the necessity for back-up safety measures. These are all challenges which come with any intensive aerospace development established or new and are already under examination. One of the high priorities in ongoing development is the improvement of autorotation (see comments below on glide)
R&D is now establishing the ideal angle of attack to achieve maximum rpm. If the motor stops it will be disconnected from the rotor as it is in a helicopter. Wind-tunnel tests have shown a steady improvement in glide-autorotation. The glide angle will be steep (1:3 )but the actual descent speed will be low and rotor speed will be high enough to allow a good landing.
Horsepower requirements for an Ultralight FanWing
The latest model takes off with approximately 20 grams/watt of power into the rotor. This ratio gives 15kg/ hp or 33 pounds of lift per horsepower. All indications are that this efficiency will improve as the size is increased and as the blade and wing shapes are improved. In the wind-tunnel tests at Imperial College some designs achieved 28 grams/watt. A 400 kg gross weight FanWing aircraft could possibly fly with 40 hp.
The rotor will probably be turning at less than 1000 rpm. The pressure on each blade is low so construction can be light and vibration low.
In vertical-take-off / hover phases efficiency will be between 30 to 40 N/kW, inevitably less efficient than a helicopter because the fan area of the FanWing is smaller. Efficiency will probably be close to 300 N/kW in horizontal flight and in this flight phase significantly more efficicient than the helicopter.
The FanWing does not stall while the rotor is powered. As speed is reduced the lift drops slowly until the limit of static lift is reached.
The wing has low sensitivity to the angle of attack. The lack of sensitivity means that it will not be affected by turbulence as much as a traditional wing.
Flight speed has already increased since 2011 and will certainly continue to increase with advanced development. The models built so far fly at between 7 and 12 m/sec. An Ultralight would fly at approximately 90 km/h.
How does the vortex control work
At the leading edge a small flap changes the entry angle of air into the rotor cage. This affects the integrity of the internal vortex and thus the efficiency/thrust of the wing. It provides an extremely simple and effective control system.
For further information contact peebles@fanwing.com