Waclaw Czerwinski was one of the leading aircraft designers in Poland before the outbreak of war in 1939. Born in 1902, he graduated from Lwow Polytechnic in 1920 and for some years lectured there and in other colleges. From the beginning he was influential in the development of Polish gliding and soaring. He became joint owner of a small glider factory. The first soaring flights in Poland were achieved in one of his early CW designs. Later he joined the larger aircraft industry and in September 1939 was working at the National Aircraft Factory at Biala Podlaska. In total he was responsible for about eighteen aircraft designs including gliders and powered.
He designed the CW 5 advanced sailplane of 1933, which had an unusual type of suspended, all-moving tailplane. In 1936 came his famous and popular WWS Salamandra. Based on an even earlier design of 1929, many hundreds of the Salamndra type were produced in the nineteen thirties, propduction was re-started after 1945, and some numbers were built under licence in China. (A replica Salamandra has been completed and flown in recent years.)
In the International Championships at the Wasserkuppe in 1937 the Polish team entered with five sailplanes. One was the CW 5bis35, there were two of the Orlik, an outstanding fifteen metre design by Antoni Kojan and to the astonishment of the contestants, two outstandingly good new 19 metre span sailplanes, of the PWS 101 type designed by Czerwinski. In performance these were probably equal to the most advanced sailplane at this contest, the prototype Reiher of Hans Jacobs. The Reiher experienced some handling problems; the PWS 101 was free of vices and achieved outstanding results. On the first day Hanna Reitsch and Heini Dittmar, the eventual winner, achieved a 351 km goal flight to Hamburg. The Polish pilot Mynarski in a PWS 101 was there too. Many distance records were subsequently broken by these sailplanes, the best of which, 577.8 km, flown by Tadeusz Gora in 1938, was exceeded only by the world distance record of the previous year, 652 km by Rastourgyev in the USSR.
Czerwinski in 1938 envisaged an improvement on the PWS 101, the PWS 102 Rekin (Shark). It was to be faster with a less cambered and thinner wing profile. Full-span flaps were combined with the ailerons. The wing in plan conformed closely to the ideal elliptical shape. Gull dihedral was retained although this created some problems with hinging the flaps round the bend. The wing now was mounted higher on the fuselage because in circling flight some cross flows usually occur and it becomes important to minimise disturbances on the upper side of the wing in this central area. The cockpit canopy was now fully contoured but not moulded. To ensure good visibility in the forward direction, the shape was somewhat bulbous to minimise distortion.
The prototype Rekin, registered SP–1126, flew first early in 1939 and proved successful. The Rekin was exhibited and flown at at least one flying meeting, with impressive results. The PWS 102 Bis, SP 1361, was built with minor improvements, such as increased aileron area.
Czerwinski’s next project was the aerobatic PWS 103, but it is doubtful if this was ever flown.
War was imminent. Under the Ribbentrop/Stalin agreement between Germany and the USSR, Poland was invaded in September 1939 from both west and east. Both these new sailplanes were captured by the Red Army. Their later fate is not known. Probably, like nearly all Polish aircraft, they were destroyed during the following years of indescribable devastation The Potsdam conference at the end of the fighting enforced huge changes of national frontiers and displacement of populations.
My information about these exceptional sailplanes came first from an account written by Czerwinski himself, published in the English magazine, Aeronautics in 1947. When preparing to write an article of my own for the Australian Gliding magazine in 1973, I corresponded with Waclaw himself in search of more details.
He was then living in Canada. With many other refugees, he had escaped first to France and then to England and in 1941, Canada, where he worked for De Havilland. Among other important development work, he devised methods of moulding plywood which were used in producing auxiliary fuel tanks for the DH Mosquito.
His interest in gliding never waned. He aroused sufficient interest among employees at DH for a club to be formed. Gliding, as he noted in an article for the magazine Flight in June 1942, hardly existed in Canada at that time. The club’s first project was to build a Canadian version of the Salamandra, which was called the Sparrow and later a slightly improved design, the Robin.
During his hurried evacuation of his home country, Czerwinski had not been able to save any of the plans for his sailplanes but he could recollect all the essential features of the Salamandra. He designed a new almost identical sailplane, the Sparrow. The DH Company directors recognised that gliders had become important as part of the war effort and were persuaded to provided materials and spare workshop space. Other companies offered instruments and a wheel for the landing gear. Re-named the Robin, the glider was completed in spare time by DH employees, supervised by Czerwinski. Not much more came of this because wartime demands had to take priority and every bit of workshop space and equipment was needed.
The war over, in 1945 Czerwinski wrote in Canadian Aviation that the CWA 106 Robin was ready for post war production. He suggested three ways in which the aircraft could be marketed; as a complete aircraft ready to fly, as a kit for club construction, or as a set of plans. The first to be completed was test flown at the Barkers Toronto Airport and found to be very satisfactory. Again, there was not much interest from the market but when Czerwinski joined Avro Canada in 1946 – 59 he became friendly with another outstanding engineer and gliding enthusiast, Beverley Shenstone, formerly President of the nascent Soaring Association of Canada. This was to have interesting consequences.
In 1947 the British Gliding Association announced a design competition for a high performance two-seat sailplane. The specification was fairly open, the wing span of 18 metres being the main restriction. Much else was left to the designers’ choice. It was not a part of the competition that the glider should be flown; everything was to be judged from the paperwork and calculations submitted. Under the terms of the contest, the winning design was to be built but no restriction could be placed on construction of other designs submitted.
Together, Shenstone and Czerwinski developed plans for the Harbinger, to be constructed of wood in the orthodox fashion of the period. There were many interesting and unusual features, especially a markedly swept forward, cranked wing with an ingenious arrangement of strut and spars which allowed a very thin profile to be used at the wing root, to reduce, as far as possible, interference between the fuselage and wing airflows. A very simple main spar, much lighter than would have been necessary for a cantilever wing, was devised.
The Harbinger was placed fifth in the competition. The winning design, by Hugh Kendal, was called the K-1 but when built, after long delays and many modifications, proved quite unsuccessful, even unsafe. The K-1 prototype, after many attempts to improve it, was eventually scrapped.
Two examples of the Harbinger were built, one in England completed in 1958 by Fred Coleman. Even before completion problems were found. Coleman was forced to extend the front fuselage to bring the centre of gravity forward. The Canadian example was not flown until 1975 with the angle of wing sweep reduced to achieve correct balance.
The English Harbinger still exists and is flown as a vintage sailplane. The Canadian example languishes, apparently forgotten, in a museum store.
Czerwinski and Shenstone collaborated again in 1949, producing the Loudon, a small sailplane of good performance which broke the Canadian distance record but was destroyed soon afterwards when struck by a squall on the ground which blew it over, damaging it beyond repair.
Czerwinski himself became a member of the National Research Council in Ottawa, and lectured at Toronto University. He died in Canada some years ago, but I have not been able to find the relevant date or circumstances.
A model PWS 101
It is not possible to fly any of Czerwinski’s advanced sailplanes now, although, as mentioned above, a replica Salamandra is extant today.
There was a project some years ago, to build and fly a new full sized PWS 101 but I have heard nothing of this lately.
One way of experiencing old time flying is to build scale models.
My own model of the PWS 101, built at quarter scale some twenty years ago, has proved very successful with docile handling and good performance in thermal and slope soaring. The second flight, from a winch launch, saw it circling away to great height. It subsequently won a couple of prizes at scale model meetings, during one of which it was hit by a carelessly flown power model. It survived under adequate control with one wing lacking 30 cm or so and the aileron jammed. (The powered model survived almost unmarked.)
After changes of ownership and some further adventures and repairs, this model 101, weighing a little under 7 kg, is still going as well as ever and looks beautiful in flight. Plans have been made available to friends and other examples are now to be seen in various countries.
Model PWS 102, Rekin
I built my first quarter scale, 4.75 metre span model of the Rekin some ten or more years ago. It flew successfully, launching by winch and aero tow, and soared well in thermals and slope lift.
This model was skinned entirely with 0.4 mm plywood except for the control surfaces and weighed a little over 7 kg, mainly because the skin covered the whole wing except for the control surfaces. (7 kg is a critical figure because models more than this legally have to be approved by an inspector before flight.) After some time I began to feel some dissatisfaction, not because there was anything seriously wrong with the model but it did not handle quite so sweetly in the air as the PWS 101. Eventually I dismantled it, saving only some of the smaller components.
I made up my mind to build another Rekin, to try some different construction methods. To describe these requires another article which I have included on my web site, martinsimons.com.au under the heading Building the Rekin.
Although not the same as flying these aricaft from the cockpit, there is great satisfaction in seeing them in the air again. Perhaps one day I will build a model of the Salamandra..