Lifting surface computer programs now exist for calculating the air forces on oscillating wings of general planform. These have made it practicable to evaluate the transient forces on wings entering step gusts by using a long-established relation between oscillatory and indicial forces. As examples, the indicial forces on a low aspect ratio wing in incompressible flow and the indicial pressures on a delta wing at a low subsonic Mach number are calculated. In the latter case the calculated results, which are based on attached flow, are compared with measurements on the same wing in conditions of separated flow. Despite the differences in flow, surprisingly similar development histories are found.

One of the difficulties in giving a talk on flight instrument displays is that everyone in aviation seems to be an expert on this particular subject—or at least everyone has such fairly violently held prejudices that new ideas tend to be automatically opposed and are certainly viewed with suspicion. I am no exception although, of course, I consider my prejudices to be calmly reasoned opinions. Accordingly, being nominated by my Commanding Officer to address this test pilots’ group I swam into the literature on the subject— and there are fathoms of it—to find that most of my “new” ideas have been put forward before and, not only that, have often been rejected on pretty good grounds.

In fact, insofar as instrument displays are concerned, history is anything but bunk and, quoting C. G. Grey of Aeroplane fame, “history is the greatest plagiarist and repeats itself to such an extent that if you knew all history one would never make a mistake in life because one would know all the mistakes that had been made”. And as you know, the difference between plagiarism and research is that if one steals ideas from more than one person, it is research.

I hope to show that many of the latest ideas on displays have been previously tried but not pursued until later technological developments made their use necessary and possible. I also hope to put forward some of my ideas on this subject.

This paper describes seven city heliports in the US, considering first their physical features and associated operating factors and, second, the possible application of the operational experience gained with these heliports to future heliport design.

Three of the seven heliports are in New York City—the Pan American Building rooftop, Wall Street Pier near the confluence of the Hudson and East Rivers, and the World's Fair Heliport. One is in Chicago, at Midway Airport. The remaining three are in California; Los Angeles International Airport, Anaheim / Disneyland, and Oakland.

Taken collectively, the seven heliports are representative of city heliport operation in the US today. Taken individually, they represent considerable variation in the significant factors affecting their operation, such as noise, height above ground level, traffic control towers, interface with other modes of transportation, both air and surface, lighting, instrument operation, obstacle clearance, turbulence, and related factors.

A forecast of future development for a period of 10 years postulates a complete change in civil air transport. Future city centre heliport developments are considered from an airport operator's point of view.

Full consideration has been given to helicopter sites in London by the Morris Report of 1961 and a VTOL Working Party of the Aeronautical Research Committee is now considering a report on the siting of Terminals for an Intraurban VTOL transport system.

Generally, the main considerations of committees on heliports consider the problems under the headings: —

1. Characteristics of the aircraft.

2. Noise limitations.

3. Safety, including aerodynamic effect of neighbouring buildings.

4. Air traffic control and operating procedures.

5. Traffic growth considerations.

6. Design layout and location of terminals.

7. Access to the city centre must be good and possibly not more than 15 minutes journey time.