Flight, June 1929

BRITISH AIRCRAFT AT OLYMPIA

THE H. G. HAWKER ENGINEERING CO., LTD.

   OF the three complete aircraft to be exhibited on the Hawker stand one will be the "Tomtit" two-seater training machine, while the other two will be a "Hart" day-bomber and a "Hornet" single-seater interception fighter, respectively. Air Ministry restrictions prevent a very detailed reference to the two military types, particularly the "Hornet."
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   The Hawker "Hart" with Rolls-Royce "F"-type engine is a high-speed day bomber, which may also be employed as a Fleet fighter reconnaissance machine. If desired the "Hart" can be put on a float undercarriage and used as a seaplane. The machine is of all-metal construction, and aerodynamically is of very "clean" design, a fact which is reflected in the performance figures. The "Hart" may be fitted with Rolls-Royce F.XI B or F.XI S engine, according to whether it is required to operate at great heights or only at medium heights. With the F.XI B engine the full speed at low altitudes is 184 m.p.h., and at 10,000 ft. 172 m.p.h. The climb to 10,000 ft. occupies 8 mins. If the supercharged Rolls-Royce F.XI S is fitted the full speed at 10,000 ft. becomes 187 m.p.h. and the climb to 10,000 ft. occupies but 7 1/2 mins. This performance refers to the "Hart" as a bomber, and to an all-up weight of 4,320 lbs.
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Flight, November 1932

British Aircraft at the Paris Aero Show

The Hawker Exhibits

   THE H. G. Hawker Engineering Co., Ltd., will exhibit a "Hart" (Rolls-Royce "Kestrel"), and specimens of Hawker metal construction.
   The particular ''Hart” to be shown will be one which has been in service with a British Royal Air Force squadron for a considerable period, and visitors to the show will thus be able to convince themselves that the very simple and light form of construction used by the Hawker firm does not, as some might suppose, give rise to any maintenance trouble during subsequent service. The success in service, particularly from the point of view of maintenance, ease of inspection, and facilities for executing emergency repairs, is a result of simplicity and the use of uncommon quantities of common sense in the design. Put quite briefly, it may be said that what has been done in the Hawker type of construction (which, incidentally, owes much of its extraordinary simplicity to Mr. Fred Sigrist, one of the managing directors of the firm) is to make a very special study of details which occur a large number of times in the machine. By reducing the size and weight of such details to an absolute minimum a great deal of weight has been saved, which can, and is, then utilised in making other parts sturdier than one could otherwise afford to have them.
   The "Hart" to be shown at Paris was flown over to Le Bourget early this week by Mr. P. W. S. Bulman, the Hawker firm's chief test pilot, and at the end of the aero show the machine will be transported back to Le Bourget and flown home to England.
   In addition to the "Hart," there will be on the Hawker stand a skeleton fuselage, which will exhibit not only the typical Hawker form of construction, but which will also attract the very widest attention for another reason which visitors to the show will discover for themselves. The actual fuselage, incidentally, will be for an "Osprey" two-seater.
   Samples of Hawker wing spars, ribs, and detail fittings will also be shown, and altogether one may expect that the Hawker stand will be crowded on most of the days during which the exhibition is open.

Flight, November 1932

British Aircraft

The H. G. Hawker Engineering Co., Ltd.
Kingston-on-Thames

   DURING the war period the name Sopwith became a household word. Sopwith machines in enormous numbers, and covering a great variety of types, were in use in many theatres of war. After the war the old Sopwith firm ceased to exist, and out of it grew the present H. G. Hawker Engineering Co., Ltd., which, under the joint managing directorship of Mr. T. O. M. Sopwith and F. Sigrist, has worthily upheld the splendid traditions of the old Sopwith Company.
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   The next type to be produced by the Hawker firm was the two-seater "Hart," a high-performance day bomber, also fitted with the Rolls-Royce Kestrel engine. The same clean design as characterised the "Fury" was found in the "Hart," and it was not long before that also was adopted in considerable numbers, and for various purposes.
   As there appears to exist a good deal of confusion concerning the various Hawker types, it may be of assistance if we outline briefly the purposes for which the various types are used.
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   In the two-seater class we may begin with the "Hart," which in what may be termed its standard form is a day bomber. As a two-seater fighter the "Hart" is known as the "Demon," and when the "Hart" is equipped for Army co-operation it is known as the "Audax."
   The "Osprey," although generally similar to the "Hart," is regarded as a distinct type, and is a fleet fighter reconnaissance machine, and can thus be regarded as the "opposite number" in the two-seater class of the "Nimrod."

Flight, June 1934

NEW AND EXPERIMENTAL

Hawker "Dagger-Hart"

   A standard machine, except for the engine installation, this "Hart" is, nevertheless, interesting on account of being fitted with the new Napier "Dagger" engine. The high power and small frontal area of this engine combine to give the machine an excellent performance, and visitors to Hendon are advised to watch its flying carefully. The wing span is 37 ft. 3 in.


Hawker "Pegasus-Hart"

   The Hawker "Hart" has been very extensively used by the R.A.F., and in sub-types it exists in various forms. Machine No. 6 is chiefly of interest because it is fitted with the Bristol 665-h.p. "Pegasus" III M engine, instead of the Rolls-Royce "Kestrel," which forms its standard power plant.

Flight, December 1934

A MODERN DAY BOMBER
The “Hart" with 660 h.p. "Pegasus" IV Supercharged Engine: a top Speed of 197 m.p.h. with Full War Load

   FEW military aeroplanes have met with such unqualified success as that enjoyed by the Hawker "Hart'' two-seater. This aircraft first came into public notice during 1929 as one of the most promising of a number of high-performance Service machines designed to use the Rolls Royce "F" engine, or "Kestrel" as it was named subsequently. Fitted with the 480 h.p. "Kestrel" I.B. unsupercharged engine, the "Hart" was adopted by the Royal Air Force as a high-speed day bomber. Soon it became obvious that the machine's performance and handling qualities were such that it was fitted to perform a multitude of duties apart from day bombing, and accordingly it was developed into the "Osprey" Fleet Fighter Reconnaissance aircraft with "Kestrel" II MS, "Demon" two-seater fighter with "Kestrel" II S, "Audax" Army Co-operation machine, "Hart" (Communication), "Hart Trainer" and "Hardy" general purpose type - all four with "Kestrel" IB - and "Hind" high-altitude day bomber equipped with the new fully supercharged "Kestrel" V of 600 h.p., for which version a sensational performance is claimed.
   Following on the official adoption of the "Hart," and the proof, in service, of its qualities of performance and easy maintenance, a number of countries became interested in the type and its variations which, subsequently, were ordered in considerable numbers. Certain of these countries for various reasons, climatic and industrial, requested an air-cooled engine as the power plant of the machine, and, accordingly, the Bristol "Jupiter" and "Pegasus" radials were fitted, and gave eminently satisfactory results.
   Early in 1934 a "Hart" was loaned by the Air Ministry and fitted with the 690 h.p. "Pegasus" III moderately supercharged engine - the first of the "Pegasus" family designed to operate on the new Service fuel of 87 minimum octane value. The latest pattern combined exhaust collector and cowling ring was fitted. Flight trials at Filton aerodrome were outstandingly good, and the results of official tests at Martlesham Heath, which were made later, credited the machine with a top speed of 185.5 m.p.h. at 10,000 ft., which height was reached in five minutes four seconds with full war load. This excellent combination of aircraft and engine made its first public appearance in the New and Experimental Types Park at the Royal Air Force Display this year and was demonstrated at the S.B.A.C. Display a few days later. Loaded to a weight of 4,635 lb. the machine took off in 110 yards and had a service ceiling of 26,000 ft. The impressive take-off may be attributed to the high power given by the "Pegasus” III for take off, which is over 770 h.p.
   Following on the successful tests of the "Pegasus" III version, a fully supercharged "Pegasus" IV engine normally rated at 660 h.p. at 11,500 ft. was installed. As was confidently expected, a very gratifying increase in performance was obtained, Martlesham figures showing that the "Hart" with this engine was capable of a speed of 197 m.p.h. at 13,400 ft. and a full load climb to 15,000 ft. in seven minutes eighteen seconds. The all up weight was the same as that of the "Pegasus" III engined version, the take off run being 134 yards and the service ceiling 29,800 ft.
   These most excellent results were obtained, not in a "stripped" condition, but with the machine carrying full military load, including Vickers and Lewis guns, ammunition, two 250 lb. bombs slung beneath the wings, and fourteen gallons of fuel over and above that demanded by the standard specification.