The Rubik R-11b Cimbora (Pal) was a Hungarian two seat glider, first flown in 1940 and intended to introduce B-certificated pilots to aero-towing techniques. It proved popular and was also used to train pilots in ridge lift flying and set several national duration records.
In 1939 there was a call from the Aeroclub of the fhe Technical University for a two-seat glider on which intermediate level pilots could learn the skills required for aerotowing. Ernő Rubik responded with the F-11 Gólya (Stork) built, like several of his designs, by Aero Ever Kft. Its first flight was on 9 May 1940. A combination of flight test results and tightening regulations lead to three more prototypes, the R-11a, R-11b and R11b1. Details of the differences between them are sparse but it was the R-11b, renamed the Cimbora that went into production in 1941.[1][2]
Designedit
R-11b Cimbora in 2015, winch-launching
The R-11 was a glider with a high, swept, strut-braced wing. The half-wings were built around two spars. Swept at 7.5°, they had constant chord out to rounded tips. Slotted ailerons occupied more than half the span. The wings were supported centrally over the fuselage by a longitudinal pair of inward-leaning steel N-struts from the upper fuselage longerons, joined at their tops and braced outboard by a pair of steel struts on each side from the lower fuselage longerons to the wing spars. On the R-11a Gólya, these were V-struts but the R-11b had instead a near-parallel pair, splaying outwards a little from top to bottom.[1][2]
Apart from rounded upper decking the ply-covered fuselage was flat-sided, built around longerons and frames. The student's cockpit was under the wing leading edge with a removable cover incorporating a windscreen and the instructor sat under the rear wing in an open cockpit over the centre of gravity (cg) with its own windscreen, accessed via an upwardly hinged upper fuselage section. On the underside a landing skid ran from the nose to below the front of the instructor's cockpit. Aft of it, but ahead of the cg. there was a semi-exposed monowheel. The fuselage tapered rearwards to the tail, where the R-11's strut-braced tailplane was placed on top of the fuselage just ahead of a small, tapered fin. The tailplane and elevators together were tapered in plan out to rounded tips. The full, rounded, balanced rudder reached down to the keel, behind a small tailskid.[2]
Operational historyedit
As well as providing aerotowing training, the Cimbora was used to train pilots in ridge-flying techniques, a style which encouraged duration record attempts. The longest in Hungary lasted 25 hr 7 min, flown by Géza Vass and Endre Lacza in August 1948. R-11bs remained in use into the 1950s.[2] A 1984 replica, HA-5035, based at Budaörs Airport,[3] remained active at least to 2016 but is currently deregistered.
^Ogden, Bob (2009). Aviation Museums and Collections of Mainland Europe. Air Britain (Historians) Ltd. p. 295. ISBN978 0 85130 418 2.
January 01, 1970
rubik, cimbora, hungarian, seat, glider, first, flown, 1940, intended, introduce, certificated, pilots, aero, towing, techniques, proved, popular, also, used, train, pilots, ridge, lift, flying, several, national, duration, records, cimbora, role, advanced, tr. The Rubik R 11b Cimbora Pal was a Hungarian two seat glider first flown in 1940 and intended to introduce B certificated pilots to aero towing techniques It proved popular and was also used to train pilots in ridge lift flying and set several national duration records R 11b Cimbora Role Advanced trainer sailplane National origin Hungary Manufacturer Aero Ever Kft Esztergom 50 and the Aircraft Factory of Transylvania in Oradea 12 Designer Erno Rubik First flight 9 May 1940 Number built c 62 Contents 1 Development 2 Design 3 Operational history 4 Specifications 5 ReferencesDevelopment editIn 1939 there was a call from the Aeroclub of the fhe Technical University for a two seat glider on which intermediate level pilots could learn the skills required for aerotowing Erno Rubik responded with the F 11 Golya Stork built like several of his designs by Aero Ever Kft Its first flight was on 9 May 1940 A combination of flight test results and tightening regulations lead to three more prototypes the R 11a R 11b and R11b1 Details of the differences between them are sparse but it was the R 11b renamed the Cimbora that went into production in 1941 1 2 Design edit nbsp R 11b Cimbora in 2015 winch launching The R 11 was a glider with a high swept strut braced wing The half wings were built around two spars Swept at 7 5 they had constant chord out to rounded tips Slotted ailerons occupied more than half the span The wings were supported centrally over the fuselage by a longitudinal pair of inward leaning steel N struts from the upper fuselage longerons joined at their tops and braced outboard by a pair of steel struts on each side from the lower fuselage longerons to the wing spars On the R 11a Golya these were V struts but the R 11b had instead a near parallel pair splaying outwards a little from top to bottom 1 2 Apart from rounded upper decking the ply covered fuselage was flat sided built around longerons and frames The student s cockpit was under the wing leading edge with a removable cover incorporating a windscreen and the instructor sat under the rear wing in an open cockpit over the centre of gravity cg with its own windscreen accessed via an upwardly hinged upper fuselage section On the underside a landing skid ran from the nose to below the front of the instructor s cockpit Aft of it but ahead of the cg there was a semi exposed monowheel The fuselage tapered rearwards to the tail where the R 11 s strut braced tailplane was placed on top of the fuselage just ahead of a small tapered fin The tailplane and elevators together were tapered in plan out to rounded tips The full rounded balanced rudder reached down to the keel behind a small tailskid 2 Operational history editAs well as providing aerotowing training the Cimbora was used to train pilots in ridge flying techniques a style which encouraged duration record attempts The longest in Hungary lasted 25 hr 7 min flown by Geza Vass and Endre Lacza in August 1948 R 11bs remained in use into the 1950s 2 A 1984 replica HA 5035 based at Budaors Airport 3 remained active at least to 2016 but is currently deregistered Specifications editData from Gabor F 2 General characteristicsCrew Two student and instructor Length 7 52 m 24 ft 8 in Wingspan 15 m 49 ft 3 in Wing area 21 5 m2 231 sq ft Aspect ratio 10 5 Airfoil Gottingen Go 549 Empty weight 220 kg 485 lb Gross weight 400 kg 882 lb Performance Maximum speed 100 km h 62 mph 54 kn VNE Maximum glide ratio 14 Rate of sink 1 1 m s 220 ft min minimumReferences edit a b Gabor Jareb 1988 Magyar vitorlazo repulogepek in Hungarian Budapest Muszaki Konuvkiado pp 99 104 a b c d e Fekes Gabor R 11b Cimbora Hungarian gliders 1933 2000 Retrieved 25 February 2019 Ogden Bob 2009 Aviation Museums and Collections of Mainland Europe Air Britain Historians Ltd p 295 ISBN 978 0 85130 418 2 Retrieved from https en wikipedia org w index php title Rubik R 11b Cimbora amp oldid 1099731357, wikipedia, wiki, book, books, library,
