Short Field Performance

Daniel Goldin, Administrator of the National Aeronautics and Space Administration, has tabulated goals of two NASA programs, AGATE and SATS (Advanced General Aviation Transport Experiments and Small Airplane Transport System). He described some of these goals as follows:

With the advent of the hub-spoke system, and increasing congestion, the average doorstep to destination speed for trips of less than about 300-400 miles (the range of most trips taken) average about 50-60 mph.

Mr. Goldin stated that there are about 18,000 airports in the U.S. but only about 700 have regular air transport service. He further stated:

Instead of paving over hundreds of small airports, let's pave the way for thousands of 'smart' airports.

He additionally observed that airplanes to furnish this greatly expanded service will have certain features:

Airframe structures should be 'smart' in the sense that they will contain embedded sensors and communications capabilities for safety and maintenance information. They can also have embedded micro-devices that control the aerodynamics for more lift and less drag depending on the flight conditions.

Everyone has seen a bird fly, they don't just have control surfaces and flaps on the back of their wing. They have three-dimensional control that shapes their wing. They're much more efficient aerodynamically than anything we can build today.

Should our goal be to develop smart structures that would not only increase performance of airframes today... but also dramatically reduce maintenance costs?

These are heady aspirations! Any airplane that incorporates these features and can perform these missions will indeed be a major step forward. Power-Wing^TM Comfort-Ride^TM airplanes meet these requirements.

PWCR^TM has been designed to meet the primary requirement of using 18,000 small airports, most of which have runways less than 3000 feet long. By using principles of circulation control, "embedded sensors", and advanced navigation and flight control, PWCR^TM airplanes can serve these fields.

Design specifications for the two PWCR^TM airplanes were to land and take-off in 2000 feet. This includes distance over a 50 foot obstacle, flare, transition, and ground roll. An additional specification was a cruise speed over 180 mph. The latter specification required a wing loading of not less than 30 lbs/ft². This, in turn, required a take-off and approach lift coefficient higher than could be achieved with even the most sophisticated flap system.

A basic question existed. Will it be advantageous to apply power to change aerodynamics of the airplane instead of using this power to only propel the airplane? Extensive analysis and the WSU feasibility study proved that it definitely was advantageous. This study considered normal take-offs, worst-case situations, and no blowing power.

Independent calculations and the WSU study gave normal take-off distances as low as 1213 feet (over the 50 ft. obstacle). Reduced blowing power still allowed take-off under 1500 feet. A variety of calculations showed that even with no blowing power, a PWCR airplane could take-off in 3000 feet (for ferrying with no blowing to a service point).

The Direct Lift Control capability assures that a PWCR^TM airplane can also land in under 2000 feet, including approach, flare and roll-out. The PWCR^TM configuration meets the goal of Mr. Goldin of using small fields.

Perhaps an even greater advantage exists in countries where the surface infrastructure has not been well developed. An analogy of PWCR^TM in air transportation exists in the advent of rail transportation in the U.S. in the mid-1800's. Laying a transcontinental railroad was a daunting task, but the steam locomotive justified this task. In like fashion, PWCR^TM airplanes will justify developing a network of small airports. Numerous examples can be cited where an air transportation system, based on PWCR^TM airplanes, is justified. See www.dragonaviation.com.