The FVA 10B “RHEINLAND”
The story of the Rheinland seems to have begun in 1932 when a student member of the Academic Flying Group of the University of Aachen, known as the FVA (Flugtechnischetireinigung Aachen) decided to design and build a sailplane for his Diploma thesis. His name was Hens Sander and we are very honoured to have him as one of our members.
In undertaking such a work, Hans Sander was responsible for giving a new impetus to aircraft design activities at the University of Aachen. No aircraft had been designed and built by the FVA since 1926. Before that time, the FVA had known a period of glory marked by such famous designs as those of the “Black Devil” of 1920 and the FVA2 “Blue Mouse” of 1921. These two gliders had not only set up world records, but had largely helped to start gliding in Europe. Since 1926 however, the students of the FVA had shown more interest in flying than in designing with the result that their Association had become more of a flying club.
Hens Sander named his glider the Blue Mouse 2 in an effort to remind the FVA of its post glory and to rekindle an enthusiasm for gliding. He certainly succeeded, for after his glider the FVA 9, came the FVA 10A in 1935. This was named the “Theo Bienen” in memory of an FVA test pilot killed in 1926. In 1936 came the first FVA 10B. It was named the “Rheinland” after the FVA 5, a successful single-seater produced in 1923, which had also been named the “Rheinland”. The enthusiasm triggered off by Hans Sander lasted until the end of 1939, by which time the FVA had designed, built and test flown three more impressive sailplanes. The outbreak of war put an end to this fruitful activity and many FVA members were called up as troop carrying glider pilots.
It is only right tbat Hens Sander, being the man who started the enthusiasm which produced the Rheinlnnd, should tell his own story.
Here are some extracts of a letter he wrote to Phillp Wills in November 1974:
“I happen to be an Honorary Member (Alter Herr) of the FVA which was initiated by Prof. von Karman and his Assistant, Wolfgang Klemperer (who were respectively responsible for the design and test flying of the original Black Devil and Blue Mouse – CW).
We had abandoned design of gliders and light aircraft after 1927. However, in 1932 I was responsible for the layout of the FVA 9 (The Blue Mouse 2) and my diploma work not only contained the calculation for lift distribution and a complete stress analysis fop the wing (equal stress, which made it possible to build this 16m span ship with an empty weight of only 92kg), but also a stability analysis.
Mr.\ Schmetz was a manufacturer of sewing needles and an old hand in the gliding world. He had worked with Focke in Bremen and. in the 1950s, he was to design and build, together with E.G. Haase and Kensche, the revolutionary HKS sailplane which had variable camber wings instead of ailerons for lateral control. The FVA 10 was a most modern design with the fuselage being an aerofoil. with a panoramic canopy and retractable landing gear. Only the “gull” wing was standard for the time”
After leaving the FVA, Hans Sander became Chief Engineer and Chief Test Pilot for ground and flight testing of prototypes at Focke Wulf from 1937 to 1945. He. is also a holder of three Diamonds (FAI No. 551).
Here are now some extracts from a letter from Dr. Artur Getto to Chris Wills dated 16th February 1976. Dr. Getto helped to design and build the FVA 10 “Theo Bienen”, the forerunner of the Rheinland which it very much resembled.
”Between 1932 and 1936, during my student years., I was an active member of the FVA. In the traditions set by Hermann Hayer, we undertook during 1933-34 to design and build the FVA 9 “Blaue Maus 2”, a strutted high wing sailplane with a plywood tube fuselage. The performance of this aircraft didn’t satisfy us during the 1934 Rhoen Contest, and we decided to build a higher performance sailplane, the FVA 10A. Bernard Sann, a member of our Group, undertook the calculation and construction of the wings. I was responsible for working out the most favourable airflow configuration in respect of fuselage shape and the wing/fuselage transition point, as well as for the construction of that area. After theoretical calculations and experiments, a model was built and wind tunnel tested. Step by step, we altered the models shape until the optimal combination was found. In order to maintain the form of the model, I designed a retractable landing skid. This was later replaced (when the sailplane was built) with a retractable undercarriage. On 1st May 1936,. I passed my Diploma examination .and went to the Darmstadt Technical High School as a scientific assistant. I therefore didn’t get involved in the flight testing of the FVA 10A, “Theo Bienen”. I learnt that Felix Kracht had made some alterations and carried out some excellent flights. Then later I heard that Ferdinand Schmetz had built more gliders of the type. The FVA 10B was the version altered by Felix Kracht. I do not know how many Rheinlands wore built. nor do I know anything about the FVA 11 ‘Eifel’.”
Here are now Felix Kracht’s recollections, as told in a letter to Chris Wills dated from Toulouse on 18th February last year:
“Thank you for your letter. It is a final proof that the sins of our youth persecute us for ever!!!!
“In answer to your questions, I will try to tell you the story of the Rheinland.
“When I joined the FVA, a group of aeronautical students from the Technical High School of Aachen, they had just reverted to their initial task of developing ideas in aircraft design. The main promoters of this movement were Dr. Doetsch and Dipl, Ing. Hens Sander. They designed and built the FVA 9″?Blue Mouse 2”, a performance training sailplane (a fair improvement on the well known Grunau Baby.) which had very good performance and handling characteristics. With this experience, the Group intended to develop a high performance sailplane, and the main task was undertaken, after Boetsch’s and Sander’s departure, by Artur Getto and Benno Sann. The main idea was to find the ideal wing/fuselage configuration with the intent to minimise fuselage drag and obtain a total CL/CD ratio which would be as high as possible.
“With the friendly help of Dr. Wiesselsberger, many wind tunnel tests wore made. When the aerodynamic definition had been frozen, I was entrusted with the complete design and stress analysis of the wing. During that time, I came to know Dr. Ferdinand B. Schmetz, an Honorary Member of the FVA. He owned a small factory (about 220 workers) manufacturing needles for sewing machines. In him I found not only a good friend but also a genial engineer. He helped me to design the wing so that it could be built in his small workshop. I would have preferred some other workshop, but his installations at least ensured the eventual manufacture, after some time, of complicated parts that we could not have otherwise built ourselves, “Under the leadership of Dr. Getto, the fuselage was designed to a minimum shape. This demanded a steering wheel type control column (because of there being no room in the cockpit to move a “joy stick” – CW) for lateral control, and for a very inclined position for the pilot. The aircraft, the FVA 10A, was called the “Bienen” after a former member of the Group who had been killed in a test flight. I had the pleasure of making the test flights for certification during the summer of 1936 and I flew the sailplane during the late summer of that year for the first tentative soaring flights. This gave me the chance of getting to know many charming places in the Tyrol and around Salzburg, but also of knowing about every local prison in the area (remember 1936!}
“During these many flights, I ascertained that the lateral control was excellent, but that the aircraft’s longitudinal stability was too high and the elevator’s response too low. In addition to this, the position of the pilot proved too tiring. But the biggest handicap lay in the “aerodynamic” shape of the fuselage. A correct landing was practically impossible at minimum speed because the tail touched the ground far too early and the spoilers which were to my knowledge the first devices of this kind, wore not efficient enough to overcome the inconvenience. So every landing was a hazard and about a year later, the aircraft was destroyed on landing by one of our less experienced members.
“My friend, F. B. Schmetz, who had closely followed our flight tests and mountain experiences, encouraged me, during the autumn of 1936, to redesign the fuselage and to add some improvements to the wings as well.
“In the meantime, the possibilities of our workshop had improved considerably. So, in October l936, my friend Franz Nekes and I started with the redesign, opting for some easier-to-build solutions and such new items as balanced air brakes, retractable landing gear with low pressure tyres, brakes and shock absorbers. But the essential thing was to redesign the shape of the fuselage to allow an easy landing at minimum speed, with or without airbrakes. This sailplane, called the FVA 10B “Rheinland”, was ready for its first test flight on 13th May 1937. There was time for only two test flights before going to Salzburg where we were to take part in the international ISTUS Competition of 1937. I ended in second place, the first going to my friend Ludwig Karch, from the Munich Group, with his famous 2-seater MU 10 “Milan”. During that time, the aircraft proved very manoeuvrable and I managed the first Alpine Crossing from Salzburg to Osoppo, near Udine. In July I flew the FVA 10B in the 1937 Rhoen Contest, again coming second to Ludwig Karch in the Mü 10. However, the FVA 10B won the Award for advanced design.
“The following year, our Group started the development of a new sailplane for very high performance, the FVA 11 for which I also designed the wing. At the same time, I was contacted by the German Aero Club with the request to put the Rheinland into production. But my first concern was to complete my Diploma.
“Once more, it was my friend F. B. Schmetz who pushed me, and the day I gained my Diploma, we founded the company of “Schmetz und Kracht GmbH” in Aachen. During the spring of 1938, we started putting the Rheinland into production. Up to 1st September 1939, we had delivered 29 aircraft. I think that the one you have in England must be one of the last ten built.
“With the beginning of the war, we closed our workshop and I joined the DFS (the German Institute for Gliding) where I remained until the end of the war. At the end of 1940, the German Government asked us to reopen our workshop and to build first the Meise (650 built) and later on, a special version of the aerobatic Habicht with clipped wings (Stummelhabicht) for training purposes.
“Having myself other duties at the time, Schmetz took over the whole job and completely transformed an old workshop for knobs next to his needle factory into a very modern glider factory.
“Regarding your question about the number 108-74: It was simply the code-to -type designation. In Germany, the number 88 designated powered aircraft and 103, sailplanes. 74 was the current number in the type certification register. Therefore 108-74 and FVA 10B both meant the sailplane “Rheinland”, in the same way that 108-30 is the code number of the Kranich. I hope that you are not too tired after this long expose`
Felix Kracht, Leader of DFS 1940-45
We are very honoured indeed to have received letters from the actual designers of the Rheinland who, as very famous men, have found the time to write to us. We thank them very warmly.
Hans Sander has kindly sent us a photograph of the FVA 10B which took part in the 1937 ISTUS Meeting It shows that the fuselage had not yet ‘been altered to that of the Rheinland in our drawing, which is the same as BGA 1711 currently flying in England. We also have a photograph of a Rheinland which flew in the 1938 Rhoen Contest. It has fully altered fuselage, like the one of BGA 1711. One therefore gathers that the first FVA had a similar, but improved fuselage to that of the FVA 10B.
Two Rheinlands were entered in the 1938 Rhoen Contest. They ended 19th and 44th, contrasting sharply with the results obtained by Felix Kracht the previous year,. Those poor positions showed how keen the competition was. Felix Kracht took part in the event in the FVA “Eifel”, but he obviously had problems.. He ended in 52nd place and scored no points. The Eifel was an 18m wing span version of the Rheinland with fowler wing flaps and a max calculated L:D 1:33!
The Rheinlands entered’ in the 1939 Rhoen Contest ended in 29th and 35th positions. The FVA 13 (the FVA’s Olympic Sailplane) came 27th.
After 1945, according to some reports, 4 Rheinlands were used by the RAF in Germany. Another was being flown during 1947 in Czechos lovakia. Another ended in the Polish Air Force Museum in Krakow. To the best of our knowledge, only BGA 1711 is still airworthy.
Although it never did so well in the Rhoen Contest as the magnificent Berlin B.5 and B.6 or Stuttgart’s FS. 18, the Rheinland now remains, together with the MU 13D and the MU 17, the only gliders stemming from pre-war German university groups still flying today.
Below are an additional set of 15 pictures of the Rheinland D-12-354 from the 1980’s when it was at the Brooklands Museum. The gentleman standing by the tail in the second shot is Bill Manuel in his later years. He was the designer and builder of the Wren series of gliders. The Swastika on the tail was a paper cut out just for the photograph and was never painted on the glider. Click below to download a zip archive file :
The ailerons and divebrakes are driven by steel torque tubes directly from the fuselage. This creates ultra effective aileron control. Coupling these tubes to pick-up points in the fuselage is done automatically. The main wing/fuselage bolts are tapered cones, which are drawn towards each other into the vertical holes in the main spar ends, by bolts.
The aircraft is remarkably refined. Wing tip spar ends had to be made of a special compressed wood (Jabroc) as spruce or pine, used in such minimum dimensions, would not have been strong enough. Only the old, undercambered wing section betrays the fact that the machine might have been designed before 1938. The undercarriage of BGA 1711 is now fixed up. This gives little clearance between the bottom of the nose, and rough ground.
In flight, BGA 1711 is a joy to fly. All controls are light and responsive even at speeds as low as 32 knots. This speed produces a faint buffet from the tailplane (or somewhere aft). BGA 1711 may fly as slowly as an indicated 30 knots but this may not be advisable as it is said that she will spin quite well if handled incorrectly. BGA 1711 is very quiet in flight and has cockpit refinements such as adjustable rudder pedals.
Landing the Rheinland presents no problem, although the landing wheel is now fixed retracted. This causes the wing to be at a not very high angle of attack on landing. It was said in “Flugsport” that the original FVA 10 had a wing at a minimum angle of attack on the fuselage. Even with the landing wheel down, it was not possible to create a sufficient angle of attack on landing to enable the wing to stall the sailplane on. Thus many fast and bad landings were made. However, by changing the fuselage, Felix Kracht managed to solve this problem completely.
The basic aim of the design is, in our view, to obtain excellent low speed characteristics thanks to a high lift, low speed wing section and excellent aerodynamics. To ensure a good performance at high speed with a high aspect ratio wing, with a wing loading that was high for the time and which produced a minimium induced drag.
The ailerons, driven by direct drive, are very light and efficient. The elevator is also easy and effective. All these ingredients add up to a sailplane that is a real pleasure to fly a ship that is something very special and which must never be allowed to fall in unworthy hands.
|Specifications for the First Rheinland of 1937 ||Specifications apply for a Rheinland similar |
to BGA 1711
|Wing sections ||Goettingen 432 at root |
Goettingen 532 three metres out
N.3 at tip
|Inner: Jukowski 4,33 Goettingen 532 |
Outer: USA M.3
|Equipped weight (with parachute) ||142 kg ||165 kg (368 lbs.) |
|Flying weight ||240 kg. ||265 kg. |
|Wingloading ||20.5 kg/sq. m ||22.6 kg/sq. metre |
|Wing span ||16m ||16m |
|Length ||7.04m ||7.06m. |
|Wing area || ||11.7 sq. m. |
|Aspect ratio || ||21.9 |
|Loading ||98 kg ||98 kg |
|Min sink speed ||0.60m/sec || |
|Speed for min sink ||60kmh (37 mph.) || |
|Max L:D ||1:28 || |
|Speed for max L:D ||75 kph || |
As the later Rheinland was heavier than the first production, one can imagine from the above figures, that its performance must be approaching that of the Skylark 2 / Ka 6 CR range.