When the President of the Engineering Section did me the honour of inviting me to read a paper on trans-Atlantic Air Services, I realised that I might be in a slightly difficult position through my association with the composite aircraft, which has been put forward as one solution of the major problem of long range flying.

I have no financial interest whatever in the adoption of the composite aircraft for British trans-Atlantic services. Imperial Airways have the free user for any of their services, and if I have any interest in its adoption it is a purely technical one. Secondly, I would remind you that an engineer who recommends a wide departure from normal practice thereby accepts a heavy burden of technical responsibility. I can assure you that with this in mind I shall not lightly make any such recommendation, but on the other hand, I shall not hesitate to do so merely because I have, with many others, taken a part in this development.

Our first phase of activity, at the Guidonia supersonic wind tunnel, was devoted to studying and designing the necessary apparatus for carrying out systematic research. (See Captain Gasperi's paper, read before the Lilienthal Congress in 1937-) This apparatus consisted principally of:—

1. (1) A series of transformer jets, to create the requisite speeds in the test chamber;

2. (2) A balance, to determine the forces exercised by aerodynamic phenomena upon the objects under test;

3. (3) The striometric and interferometric apparatus.

The initial study was long and laborious; since we lacked the great help furnished by previous research, which is nearly always forthcoming in similar studies, we had to proceed by means of successive experiments until the apparatus took its final shape. Eventually we evolved a series of jets, a balance and an optical installation which we hope are permanent. These, however, being still under construction, have not yet been tested.