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The SLINGSBY TYPE 7 CADET 

by John Stanley Sproule, it's designer. 

The true story of the Cadet is that I joined Slingsbys in mid 1936, coming from Vickers and Manuel at Dunstable, after I had great difficulty in getting my "C" licence on the London Gliding Club Prüfling. Although it controlled very well, the Prüfling was a poor glider for beginners as it had a marginal soaring performance. If a beginner flew two or three mph too fast, what was intended as a "C" attempt ended up with a descent to the bottom. I did this many times indeed. So, to soar the Prüfling, you had to be an expert, which was a daft state of affairs for a beginner's machine. The only alternative to the Prüfling at the LGC was the nacelled Dagling, which would soar in a brisk wind, but which frightened you to death because the ailerons were so ineffective. The only other "C" getter of the time was the "Hols der Teufel", an overgrown Dagling, which would soar very easily indeed due to the light wing loading, but again with poor lateral control.

 So when I arrived at Kirbymoorside the first thing I did was to persuade Fred Slingsby to let me have a go at a better "C" machine. As I seemed to have a free hand on my new "C" getter, 1 set about crossing the "Hols der Teufel" with the "Prüfling", and arrived at the "Kadet". It was a compromise between the two, combining a somewhat lighter wing loading than the Prüfling with improved ailerons. 

I see from my log that I did the first test hops at Sutton Bank on 11th January 1936, and that the first soaring flights at the same place on 20th January. The first demonstration at Dunstable was made on 26th January. We therefore wasted no time on what we now call marketing! I remember the January date for the first tests was arctic cold and the ground at Sutton Bank was frozen solid. At the time, Fred Slingsby was confined to bed with flu and I remember he was propped up in bed when 1 reported to him what had happened.

Fred Slingsby was rather funny with me about the Cadet afterwards, especially when it began to sell well. He was not eager to acknowledge that I had created this machine by myself, and, in his only writing about that period, says that the Cadet had a "disappointing performance." This was not true, because the first and lighter pre-war Cadets soared very well in some ways. So far as 1 can recall, 1 do not remember Fred ever flying it, and I think this "disappointing performance" idea was fixed by an episode 1 had at Barrow-in-Furness, where I was demonstrating to the local gliding club. Instead of making the intended landing on their, rather faraway beach - as they said their Dagling could do, 1 had to land in an intermediate field where -there was a hostile farmer. No wonder I had to land, as I had been launched with a slight tailwind, and must have been flying through a belt of descending adiabatic wind. But they wanted to see the machine fly, and 1 had to perform notwithstanding. 

The Cadet was spoiled when the ATC took it up, but they provided the bulk of the orders, so who could argue? I thought a lot of weight was added by strengthening in unnecessary places. A ton of paint was applied instead of the original light dope and varnish. Thick control cables were specified which were strong enough for a Vulcan bomber! No ATC chap could ever have applied a control force anything near to the loads the Royal Aircraft Establishment laid down as having to be catered for. But that's how it goes. At that time, new designs were submitted to a BGA stress consultant, called "Mr. Smith of Supermarine". For a fee of £10, Mr. Smith would tell you whether your design was strong enough or not and offer suggestions. On the Cadet, all Mr. Smith called for was a slight lengthening of the blocks where the struts attached to the wing spars. I never met Mr. Smith, but for £10 he did a good job, because nothing ever broke on anything he passed as OK - to the best of my knowledge. I have often wondered whether he was the successor to the famous Mitchell, designer of the Spitfire, i.e. Mr. Joe Smith. Does anyone know who "Mr. Smith of Supermarine" really was, for if he is still alive I would very much like to meet him? 

Chris Wills adds:- The Cadet was thus related to the Hols der Teufel, and its forerunner the RRG Zögling, as well as to the Prüfling. In 1952, the wings of the Cadet, which were basically those of the Zögling, were used for the Slingsby Grasshopper Primary. Many Grasshoppers have been disposed of by the ATC and are now in the hands of our members. 

DATA
Wingspan     11.73m 
Wing Area 15.8 sq. m
Aspect ratio 8.71
Wing profile Göttingen 436
Length 6.16m
Empty weight 134.5Kg
Flying weight 232.7Kg
Wing Loading 14.07Kg/sq.m
L/DMax 26 Kts
MinSink: 2.07 kts
Total built  460

The best flight that was made by a Cadet was probably a cross-country of 162 miles by John Jefferies, from Dunstable. This Cadet was owned by the late Peter Fletcher who had it modified with rounded wingtips. In 1978 he gave the Cadet to the RAF Museum, who have restored the wingtips to their original form. It and the Replica Cayley Glider have been displayed in the main gallery at Hendon. 

We believe that the original spelling "Kadet" was changed to "Cadet" for the sake of Anglicisation when the RAF accepted the glider as an ATC trainer just before the war. In 1937 The Kadet was developed into the Tutor. These two sailplanes trained generations of British glider pilots. Many Tutors are still in use, and every time John Stanley Sproule sees one flying I am sure he must be proud at the thought that a machine of his design should have done so much to help and give pleasure to glider pilots for so long. 

In his article, John Stanley Sproule has raised the issue of recognition. This is naturally a delicate issue, involving personalities, but it is accepted by other knowledgeable and impartial people that Fred Slingsby had the policy that all machines that came out of his factory did so under the name of Slingsby Sailplanes. In this, he was no different from other manufacturers. Fokker's famous aeroplanes of the First World War were for the most part designed by somebody else who was kept in obscurity. The "boss" got the credit - at least, on the surface. In the case of the Cadet there is little doubt that the gliding community at the time knew who its designer was.

 

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