M.Simons The World's Vintage Sailplanes 1908-45

THE RHOENADLER

  The first professional glider manufacturers began in small ways building primary gliders and training sailplanes, with the occasional special contest aircraft made to order. When thermal soaring was discovered and gliding clubs ДальшеMore>>> were formed all over Germany, on the populous lowlands as well as in the mountains, the market for high performance aircraft really began to expand. It was believed if someone could produce an aircraft like Lippisch’s Fafnir, for a fraction of the cost, the sport of soaring would become accessible to all. The first to seek a development of this kind was Alexander Schleicher who, at Poppenhausen in the valley below the Wasserkuppe, was in a good position to obtain the best advice from Lippisch and his team who lived on the summit. Among the RRG group was Hans Jacobs, who had already designed the later version of the Hols der Teufel which Schleicher was building. Schleicher asked him to design, for factory production, a high performance sailplane. Savings in costs were to come, as far as possible, from simplifications of structure. Schleicher’s own sailplane, a high-wing type with a strongly tapered planform, had as much influence on the design as the Fafnir.
  A straight wing with a single spar was drawn out for the new type. The wing section of the Fafnir, Goettingen 652, was used again but was somewhat reduced in camber to give a better speed range and also to simplify construction. A generous washout was built into the wing to prevent tip stalling; a sailplane to be used by clubs would need safe handling characteristics.
  Jacobs simplified the wing-fuselage junction by placing the wing on a pylon or narrow neck above the fuselage. The pilot's headrest then came just below the leading edge of the wing and a smooth wooden cockpit canopy, with side portholes, was designed. The cockpit was made large enough for most pilots. The tail unit was similar to that of the Fafnir but the rudder was increased in area.
  The resulting sailplane was called the Rhoenadler, the first of Jacobs' long series of successful high performance, factory-built sailplanes. The prototype was ready for the 1932 Wasserkuppe contest, and Peter Riedel flew it. His performances in the Rhoenadler attracted favorable attention both to him and the aircraft, which handled very well and performed with the best.
  After the contest Schleichers prepared for production. A few modifications were made. The Fafnir had suffered from its low tailplane position, which made this component vulnerable to damage on take off, and Groenhoff had died as a result. On the production version of the 'Adler, the tailplane, of all-moving type, was raised to a position part way up the fin. The wingspan was slightly reduced to 17.4 metres, and the wooden canopy was replaced by a transparent hood. Orders soon began to come in. A few Rhoenadlers appeared at the 1933 meeting, more still in 1934, and by 1935, out of 60 sailplanes at the Wasserkuppe, 23 were Rhoenadlers. At this meeting, on 30th July, four pilots, Brautigam, Oeltzschner, Heinemann and Steinhoff, headed off with a following wind in an easterly direction and all four ended the day on the aerodrome at Brunn in Czechoslovakia, setting a new record of 504.2 km. They were the first pilots to exceed 500 km in soaring flight. Steinhoff flew a Rhoenadler, Heinemann a Rhoensperber and Oeltzschner a Condor. Only the DB-10 flown by Brautigam was regarded as a ‘special’.
  At the 1936 Rhoen meeting there were still 20 Rhoenadlers out of 61 entrants.
  In 1934 a single Rhoenadler was exported to England. Eric Collins, the leading British pilot, used it to set a new distance record of more than 150 km, and in the following year made a dramatic arrival at a Royal Aeronautical Society air display. The site was the Fairey Company’s aerodrome, west of London. It was hardly known, at that time, by its name of Heathrow. Collins was to have been aero-towed there from Reading, but the tow rope broke soon after take off. He then finished the journey by soaring and ended with spectacular aerobatics before landing silently in front of the applauding guests.
  Soon afterwards Collins was killed doing aerobatics for Cobham’s Air Circus in a Grunau Baby. His Rhoenadler continued to fly and survived the war to reappear in 1946 at the first post-war aero-towing and winch launching meeting at Rearsby. This meeting was its last. When soaring at about 1500 metres, there was a loud crack in the wing and the Rhoenadler began to pitch violently up and down, throwing the pilot about so much that, with the cockpit canopy broken off, he was able to look over the top of the wing to see the tail. The seat came loose and slid forward, jamming the stick. After a desperate struggle he managed to regain control and landed safely in a ploughed field without further damage. Subsequent inspection showed that the plywood skin of the wing 'D'-nose had failed. The Rhoenadler was then scrapped and burned. Probably the last surviving Rhoenadler was the one which was still flying in Switzerland, registered HB-312, for several years after the Rearsby incident.
  This sailplane made Jacobs’ reputation and also provided many later designers with their inspiration. Jacobs’ own Weihe of 1938 closely resembled the 'Adler in appearance. In 1979-80, a replica of this famous sailplane was built by Klaus Heyn of Germany.

  Technical data:
  Rhoenadler: Span, 17.46 m. Wing area. 18.0 sq m. Aspect ratio. 16.8. Empty weight. 170 kg. Flying weight, 250 kg. Wing loading, 13.85 kg/sq m. Aerofoil, Goettingen 652 modified. Best glide ratio 1 : 20.

M.Hardy. Gliders & Sailplanes of the world

Schleicher Rhonadler

  The Rhonadler (or Rhon Eagle) high performance single-seater was designed to enable pilots to make long cross-country flights by soaring in thermals, and first flew in 1932; at this time the techniques of long distance soaring flight were beginning to be explored in earnest by sailplane pilots, and distance covered rather than time spent airborne was what pilots were aiming to achieve. The Rhonadler was designed by Hans Jacobs, who was also responsible for the DFS Meise and Kranich, the DFS Weihe, the Rhonbussard and Rhonsperber, and the Rhonadler was the type that began his unrivalled record as a leading sailplane designer. It made its competition debut in the 1932 Rhon contest, and its fine flying qualities thereafter made it one of the leading types in prewar European competition flying; production was undertaken by Schleicher at Poppenhausen. The cantilever two-piece high-set wings have straight taper to the tips, and are single-spar wooden structures with fabric covering; the ailerons, like the Condor's, are long in span. The wooden fuselage's cross-section was wide enough to allow a fairly roomy cockpit, and the landing gear consisted of a single wooden skid under the forward fuselage. The wooden cantilever tail has a large rudder and an all-moving tailplane set low on the fin.


Span: 57 ft 1 in
Length: 23 ft 7 1/2 in
Wing area: 193.8 sq ft
Aspect ratio: 16.8
Empty weight: 375 lb
Max weight: 551 lb
Max speed: 80.5 mph
Min sinking speed: 2.5 ft/sec
Best glide ratio: 20:1