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January 1945

This issue of the journal contains a series on H2S

From time to time imaginative writers such as Verne, H. G.Wells and Olaf Stapledon have attempted to make extrapolations from the march of scientific events and so to anticipate the devices which would appear at some future date in the world's history. Among all conceptions of romantic methods of extending the faculties of mankind none is more picturesque than the radar device which simultaneously makes it possible to see in the dark, to see at a distance beyond the range of unaided vision and through fog and cloud.

To different degrees these facilities are provided by the majority of radar instruments; but the achievements of H2S combine these three facilities in a way which not only exceeds any figment of the mind of any imaginative writer of the past, but which has provided the air forces of the United Nations with an increase in the accuracy of their bombing such that the number of bombs finding their target is approximately three times the number doing so without radar aids.

It is true that this increase in accuracy is not due to H2S alone, there are a number of other devices which provide equal or greater accuracy of bombing, but these all depended on the provision of ground stations affording radar cover over the region where bombing is required to be carried out. The regions accessible to bombing by means of such aids are restricted by the range of the ground stations and by the degree to which the enemy is capable of jamming the ground station transmissions. In the case of H2S, the co-operation of ground stations in friendly territory is not required and the range of aircraft using H2S is therefore limited only by their normal operational range as determined by their bomb load and the capacity of their petrol tanks. Further H2S is very hard to jam.

The attempted achievement of H2S is broadly to provide in an aircraft a map of the territory over which the aircraft is passing with a plot on it of the position of the aircraft and the point of impact of a bomb released from the aircraft at any time. It is true that as yet the degree of definition of this map, and also methods of computing the correct point of bomb release leave much to be desired, and work is continually in progress to improve these points; the fact remains that the definition is adequate to show up the form of major landmarks such as coasts, rivers, lakes and towns and the detail and accuracy provided have been sufficient to direct many tens of thousands of bombs to their destination.

Without H2S the bombing of Berlin and many of the large towns deep into Germany would not have been a practical proposition at all except in daytime in clear weather.

In addition H2S has a wide use in the form of ASV, and has been used in landing craft and in tail warning equipment. It is hoped to publish articles on these aspects in a later issue of the journal. Its use for Army reconnaissance purposes is being explored.

The series of articles which follows has been designed to present a broad picture of the scope of this device, with enough detail to give a comprehensive picture of its principles and applications. Equipment descriptions have sometimes been simplified for clarity in presentation and should not be regarded as replacing specifications or operating instructions.

Any opinions expressed are the opinions of the individual writers, and, while these may be the result of wide experience, they are not to be read as an expression of any official attitude.

Please note: the original of this document is typewritten. I OCRd the whole of the document to produce a text file and then used that to create these web pages. In the original document there are references to page numbers - to the best of my knowledge I have linked these to the correct page. You may find errors in the OCRing and also in the original document for which my apologies - I corrected quite a lot of the typos that were in the original. There are lots of Greek symbols in some places, hopefully I have found all these, along with the integrals and square roots.
Colin Hinson.

HISTORICAL NOTES ON H2S ........ A.C.B.Lovell Ph.D.
FUNDAMENTALS OF H2S ........F. C. Thompson Ph. D.
THE H2S AERIAL PROBLEM....N. .Alcock M.S. & F/Lt . D. W. C. Ramsay A. F. C.
THE NEW H2S's........J. B. Smith B. Sc.
(a) H2S Mark IV
(b) H2S Mark VI
H2S AND THE NAVIGATOR....... F/Lt. E. L.Killip A. F. C.
AMERICAN H2S AND ASV ...............B. J. O'Kane Ph. D.

If you have any comments, complaints, suggestions, requests etc, please drop me a line via my Genuki email page.

Page last updated on 10th February 2018 by Colin Hinson.