The Air Vehicle 1985

Some scientists make the following predictions for the air vehicle of 1985 concerning its aerodynamics, propulsion, structure and air­borne avionic systems:

Aerodynamics

There are two basic areas in which technological development will directly increase the performance of an airplane: 1) the lift/drag ratio¹ in cruise², and 2) the high-lift capability, which dictates take­off and landing field requirements. These are dominant factors in se­lection of the airplane wing area and power plant size. In general, the smallest airplane that can perform a given payload-range task is the most economical.

Propulsion ■ . .

Gas turbine engines have undergone remarkable technological ad­ vances in the past 20 years. Further advances will be demanded as airplane size increases, more speed is desired, and VTOL³ and STOL⁴ aircraft are developed. The application of the vehicle will dictate the specific operating improvements desired. As the weight of the air ve­ hicle increases, engine thrust must increase to maintain acceptable runway⁵ length and cruise altitude. At the same time, fuel consumption must remain low without increasing the engine drag and weight, so that operating cost can be kept to a minimum at cruise. To keep the lowest fuel weight for the particular mission, engine thrust must be matched to airplane drag at minimum fuel consumption. In general higher thrust will be demanded along with a corresponding decrease in engine weight and fuel consumption. . . -., ,

Structures

With lighter structures, air vehicles can carry heavier payloads. Structure research continually strives for higher strength/weight ratios⁶. There have been steady improvements but no revolution in this area over the past 20 years. Most airplanes are still constructed of aluminum-alloy components.

The next decade will see greater advances in stabilized-element structures and increases in strength. Advanced titanium alloys and composite materials, with more strength per pound than aluminum, will be used to reduce weight. Advanced composites have even higher potential than the titanium alloys and are most promising for the rest of this century.

On the horizon today are new structural concepts. One of these concepts results in the use of fewer frames and stringers⁷ and in a 20 per cent weight reduction. Factory production of this type of structure will require improvements in construction techniques, using a higher degree of automation.

Airborne Avionic Systems

Airborne avionics⁸ for the airplane of 1985 will be improved in reliability and performance. Reliability will be increased by a combi­nation of improved components and better system design. Performance will be improved primarily by the large-scale use of on-board digital computers. On-board equipment will process data from various sour­ces and perform computations for navigation and flight control.

Air-to-ground communication will be provided by automated or semiautomated VHF⁹ and UHF¹⁰ modulated data links. Reliable air-to-ground communication in remote areas will be provided by a satellite system compatible with the airborne data links.

High control systems for airplanes in 1985 will have been expanded from simple yaw (oscillation) dampers¹¹ to include automatic three-axis stabilization. High control system in current use depends on mechanical linkages between the pilot's controls and the controlled elements. Many problems associated with this mechanical transfer will be eliminated or greatly simplified by electrical signal transmis­sion. By 1985 electrical signalling in airplane control should be well established. The technological advances in airborne avionic systems will be reflected in performance improvements which will benefit passengers, aircrew, airline operators, and airport operators. This will result in more efficient use of space and more safety and comfort for the passengers.