The history of the aircraft industry has been marked with innovations that have contributed in varying measure to the development of the present day aircraft, with each innovation recognizing or anticipating a changing need as ground transport gradually gave way to air transport. Early innovations in this development were directed to the range, speed and cargo capacity of the aircraft, with later innovations aimed at improved maneuverability and lift as aircraft size and weight increased and as urban areas mushroomed to lessen the adequacy of the city-based airport.
With the obsolescence of the city-based airport, new airports of more adequate acreage were established in areas remote from the cities, at distances ranging from 10 to 50 miles and frequently necessitating more land-travel time than flight time. Although aircraft accessibility was improved with the advent of air-shuttle and land-limousine services, the latter have provided but slight reduction in land-travel time, and air-shuttle service has remained out of the financial reach of the general public. With the advent of todays giant sized aircraft, even the remote-area airports have required expansion, with runways being lengthened to satisfy their take-off and landing requirements.
In recognition of the lift limitations of the fixed wing aircraft and the cargo limitations of the helicopter, further innovation is required if present airport patterns are to be altered, with remote-area airports ever expanding to accommodate commercial aircraft, and with city airports remaining the exclusive property of private aircraft and helicopters.
Attention then might well be directed to variable lift, cargo carrying aircraft that have the capability of taking off and landing on either the shorter runways of the city airport or the longer runways of remote-area airports, thereby preserving the utility of existing airports while at the same time bringing the ultimate destination of the traveler within more accessible and convenient reach, with land-travel time reduced to its former more proportionate ratio. Further attention might well be directed to an advancing-wing variable lift aircraft that has the lift advantages of the helicopter and the cargo capability of the commercial aircraft.
Notwithstanding the recognized high land-travel time ratio referred to above, and the emphasis in cargo capacity that has dominated the development of the modern fixed-wing aircraft, the disadvantages of the fixed wing and of the helicopter have long been known. Whereas the fixed-wing aircraft relies on forward propulsion or thrust for lift, the helicopter relies on the rotation of its rotary wings or airfoils. Although the lift limitations of the fixed-wing aircraft have been overcome in part by the development of high powered propulsion engines, these power plants, in combination with increased cargo capacity, have mangified rather than solved the airport dilemma, and have rendered the ultimate destination of the traveler all the more inaccessible. On the other hand, the characteristic lift limitations of the rotary wing aircraft, with their variation in air speed from wing tip to rotor, render them inappropriate for cargo carrying purposes.