| E-210 | |
|---|---|
 | |
| General information | |
| Type | 4-seat tourer |
| National origin | Czechoslovakia |
| Manufacturer | ČKD-Praga |
| Designer | |
| Number built | E.210:at least one; E.211:one |
| History | |
| First flight | 13 February 1937 [1] |
The Praga E-210 was a four-seat, twin-engined touring aircraft built in Czechoslovakia in the late 1930s. It had an unusual pusher configuration . Its tail unit and undercarriage were modified significantly before World War II and after the war a more powerful version designated E-211 was flown.
In 1935, Jaroslav Šlechta , chief designer of the aircraft department of ČKD, began development of a twin-engined, four-seat light transport aircraft, to be powered by 60 kW (80 hp) Praga D engines, suitable for use as an air taxi as well as for private use. The design of the proposed new aircraft, the Praga E-210, had progressed sufficiently by November 1935 for ČKD to submit a request to the Czechoslovak government for a contract to build a prototype. [2] A contract for construction of one prototype was signed on 16 March 1936, with one change from the original proposal being the use of proven Walter Minor rather than Praga D engines, as it was felt that the risk of combining the untested Praga D engine with a new airframe would be too high. [3]
The Praga E-210 was publicly unveiled at the Paris Exhibition in November 1936, [4] with Praga having sending the externally complete, but untested and unflown prototype to the show where it was displayed on the Czechoslovak stand. [5] It was a high wing cantilever monoplane, with an enclosed cabin for four ahead of the wing and in 1936 a conventional tailwheel fixed undercarriage and single fin. It was unusual in adopting a pusher configuration, with two engines close to the fuselage driving small propellers. Its layout was thus much like that of the Carden-Baynes Bee, its almost exact contemporary though a much smaller aircraft.
The wing of the E-210 was made in a single piece, a wooden structure built around two spars and plywood covered. The leading edge was significantly swept, but the trailing edge was straight. The ailerons were steel framed and fabric covered. Between them and the engines were Schrenk type landing flaps. [6] The 85/95 hp (63/71 kW) Walter Minor four cylinder inverted in line engines were cantilevered from the rear spar on steel frames, with fairings both above and below the wings. [7]
The flat sided fuselage was built on a steel tube framework, narrowing to the rear. The rounded nose and the cabin were plywood skinned and the rest fabric covered. The spatted mainwheels were mounted on short cantilever struts, making only a shallow angle to the ground and with the shock absorbers inside the fuselage. [7] On the original aircraft there was a small castorable tailwheel, [7] but later this was supplanted by a spatted, steerable nose wheel with a faired leg. [8] By mid-1937 the original single fin [4] had been replaced by a twin endplate fin arrangement. [8] [9] The fixed surfaces were wooden framed and plywood covered, the tailplane attached to the top of the fuselage and braced externally from below. The split elevators were fabric covered over wood, with trim tabs and the horn balanced rudders were of fabric covered steel. [7]
The cabin was well forward of the leading edge, providing good visibility, and seated four in two rows, the front seats having dual control. There was a baggage compartment behind the rear seats, accessible from inside. [7] Photographs show that access to the cabin was through a single, port side door. [7] [8] [9]
The prototype made its first flight on 13 February 1937, but the flight was quickly terminated owing to engine overheating. [1] These overheating problems continued during testing through the next few months, while the aircraft's rudder was found to be ineffective. [10] By the July 1937 Prague Aero Show, the aircraft had been modified with a twin tail. [9] Other changes made at around this time included the replacement of the original tailskid with a tailwheel. [10] Testing of the revised prototype continued into 1938, [11] but in the summer of that year it was decided to carry out a major redesign of the aircraft with the prototype being rebuilt to the new standard. A new wing of greater area and different aerofoil section was fitted, with flaps being removed, and the tail surfaces were revised, with larger fins and a shorter span horizontal tail. The undercarriage was also new, with a tricycle undercarriage, the first used in a Czeckoslovak design, replacing the original tailwheel landing gear. [12] Modification of the prototype was delayed by priority being given to modifications to the Praga E-51 reconnaissance aircraft, and the modified E-210, sometimes called the E.210-I, did not arrive at Letňany Airport for testing until April 1939, after the German Occupation of Czechoslovakia, [12] and first flew in its new form on 18 April 1939. [12] The aircraft's handling characteristics were still not up to expectations, because the prototype was soon modified again, with a third, fixed, fin added. The aircraft was flown in this state on 15 May 1939, with testing continuing until August that year. [13]
It did not fly again until August 1940, when it underwent a further series of tests against German requirements and regulations. These tests continued until February 1941. [14] Later that year, following an instruction from the German Ministry of Aviation, the prototype was re-engined with German Hirth HM 500 four-cylinder air-cooled engines rated at 77 kW (103 hp), flying with these engines for the first time on 14 June 1941. [15] On 18 June, the aircraft was taken over by German authorities and flown to the Luftwaffe test centre at Rechlin. [16] It is reported that following further testing, the prototype was used as a liaison aircraft, being sighted at Berlin during autumn 1944. [16]
An E-210 was at the first post war Paris Exhibition in late 1946. Praga continued development and in 1947 produced the E-211. This used the more powerful, 105 hp (78 kW) Walter Minor 4-111 engines and had a central fin in addition to the endplates. It had the tricycle undercarriage of the earlier E-210, but was now described as a 4–5 seater and had better access, with a starboard side door opening onto the front seats and a port side door for the rear seat passengers. The door revisions brought in train some changes to the side glazing of the cabin. Fin and tailplane were covered with fabric, in place of the plywood covering of the E.210. [17] [18] [19]
As far as is known, only one E-211, registered OK-BFA, was built. There were plans for a light freighter version of the E-211. Also planned and under construction in late 1947 was an 8-seat development, the E-212, [17] but it may never have flown.
Slovakia 
Data from Grey 1972, p. 94c
General characteristics
Performance
