AVIA BH.1 (Exp.)*
The First Aeroplane Design of the Avia Company
The Avia BH.1 is the first powered aircraft design of the new Czechoslovak Avia company established as early as in August 1919 in Prague. The first acting partners in an venture called exactly „Avia – dílny na opravu a výrobu letadel“ (ie. Avia – Aircraft Repair and Manufacturing Works) were the engineers Pavel Beneš and Miroslav Hajn (designers), J. F. Koch (later designer of the famous Praga and ČZ motorcycles) and Václav Malý, an enterpreneur and businessman, who was always in search for money and business for the company. In start the new firm with premises in Prague-Vysočany even accepted non-aviation contracts for the five carpenters and three fitters employed, so they produced at least wooden propellers for models, boomerangs etc. to provide some cash flow and stay afloat.
In the time-frame 1919-1920 Beneš together with Hajn started the work on their first powered aircraft design (before the First World War they have designed and built a couple of their own glider designs). They applied their past experience with „thick“airfoil profiles checked up sufficiently on their many flyable models by draft of this new design. They were inspired by German designs of Hugo Junkers and Anthony Fokker, too, whose airplanes have already shown their qualities during the Great War in combat. Their BH.1 (Exp.) was en experimental wooden prototype. The fuselage was plywood sheet covered, wings and tail were fabric covered. In this era in 1920 were Beneš with Hajn rather daring with their low wing aeroplane arrangement, as well as with use of their originally designed airfoil, wing-to-fuselage attachment - patented later, too - and the simple floating rudder without vertical stabiliser, whose stabilising function took the whole flat rear fuselage.
The work on the prototype started in the end of Winter 1920 and went very quickly, so on October 9 of the same year the pilot Josef Novák (borrowed from the Aero company) could accomplish the maiden short hop into the air to a height of approximately three feet above ground (1 metre). By this occassion some minor flaws in the engine installation were found and the engine was still not covered. The first real maiden flight to the altitude of 50 meters (164 feet) took place on October 13, 1920. The plane was ready for flight next day and this time it stayed in the air for 10 minutes. The BH.1 surprised by good handling and flying characteristics. The only flaw was the old pre-war Austro Daimler engine delivering insufficient power. Thus the plane could carry only one person accordingly.
Immediately after these initial in-flight tests the prototype was transported to the Prague Fair Grounds into the Industrial Palace, where the First International Aviation Exhibition took place. At the Avia stand there it took well-earned attention and received a lot of publicity. The exhibition took place under protectorate of T. G. Masaryk, first president of the new Czechoslovak Republic, and he presented the Avia company a sum of one hundred thousand Crowns from his funds to support further development. This meaned a lot for the young company as Václav Malý was already nearly bancrupt at the end of the year 1920 and the perspective of further expansion would surely call for more financial investments. After the exhibition few minor modifications were carried out on the prototype, which flew in this form till April 1921. At this time it was disassembled and rebuild as the BH.1 bis type.
BH.1 bis differed from the original prototype by the installation of more powerful French Gnôme seven cylinder radial rotary engine, the wing was now covered by one-milimetre thick plywood up to the rear wing beam, the main undercarriage was modified, too and the whole airplane received silver paint finish overall. Modified prototype could now carry two-man crew at last and as such appeared very often at various aviation displays in Czechoslovakia. In September 1921 it took part in the First National Aviation Meeting gaining the first place in dependability competition during the „Flight Around the Republic“ flown on the route Prague – Olomouc – Nitra – Vajnory – Olomouc and back to Prague. The victory of BH.1 bis against much powerful competition was interesting by the fact, that she did complete the course of 536 miles (860 km) at an average speed of 78 mph (125 km/h). This showed clearly the technological advance of the design and owed much to the airframe cleanness and perfect airmanship of its pilot Bohuslav Munzar.
The aircraft remained in the company possesion and flew on more promotional aviation campaigns to gain publicity such as at various aviation days etc. Many well known pilots have tried out its handling. It was being flown usually by a noted rich lawyer JUDr. Zdeněk Lhota, who became very famous later by his accomplishments in international air racing. Once again on August 27, 1922 the aircraft took part in the Aviation day of the Západočecký aeroklub Plzeň (Western Bohemia Aeroclub Pilsen), where the already mentioned aviator Lhota flew it on display. After that the prototype was loaned to another noted pilot Capt. Jan Popelák, but he did damages to it in an emergency landing during a military exercise. As the Avia company already worked on new aircraft designs the prototype was never repaired again. The remaining parts were stored in the yard of the Avia workshops at Vysočany where they decayed. Today only its very damaged wing halves remain stored in the deposit of the National Technical Museum Prague (NTM).
Based on success of the BH.1 type the Avia company has developed and build a subsequent series of BH.3 single place fighter aircraft used by the Czechoslovak Air Force and the line continued with the types BH.5, BH.9, BH.10 and the BH.11, which were worthy successors to the original BH.1 prototype and flew not only in the skies over Czechoslovakia, but abroad, too. However their development and manufacturing work materialized under the new ownership of the Avia company, as the whole assets were bought during Summer of 1921 by a millionaire entrepreneur Miloš Bondy from Prague. Thus the complete name of new firm was then „Avia, továrna na letadla Miloš Bondy a spol.“ (Miloš Bondy & Co.), so the Avia brand still lives on as a famous company name until today.
*Abbreviation „Exp.“ stands for Experimental, but later served as source of the contemptuous nickname „Exprevít“ (ie. Extra-shit or Extra-squirt), under which the plane was later widely known…
In 1934 aircraft designer-engineer Šlechta was leading the design bureau of the Aircraft Department within the ČKD (ie. Českomoravská-Kolben & Daněk) concern, which was supposed to be dissolved because of lack of work. At that time a need arose for a light, reliable and low-cost aircraft to train new pilots in the action „1000 pilots for the Republic“ then running in Czechoslovakia. Šlechta took this opportunity to push ahead production of a prototype aircraft designated Praga E 114 at the ČKD headquarters. This was an all-wood high-wing cantillever monoplane with auto-stable wing airfoil with closed cabin and with two-crew seats placed side by side. This was at that time (mid-Thirties) very modern sport-plane concept, later widely used in the whole world over various Cessna models up to many other current aircraft designs of today. Already in September 1934 the prototype took part in the air race „Národní let RČS“ (ie. National Flight around Republic Czechoslovakia) and fared well, although it has had the less-powered engine from all participants, but in the end went out of the race thanks to an oiled-up sparkplug of its 36 HP Aeronca two-cylinder engine. A short time later in December 1934 the prototype flew air display at the Paris Aerosalon performing even the basic aerobatics. The route to Paris and back to Prague was flown in 13 hours netto only. At the beginning of 1935 the prototype was put under scrutiny in thorough flight tests at the Military technical aviation institute in Prague-Letňany. In April 1935 the E 114 flew to Brussels in Belgium to be displayed in the Czechoslovak pavillion at the World Exposition.
Series production of E 114 aircraft was prepared with a new trade type name „Air Baby“ suggesting destiny and relation to other famous ČKD product – small car Praga Baby, which was very popular in Czechoslovakia then. The airframe was beefed-up at some places and the prototype of new Czechoslovak 36/40 HP Praga B aircraft engine was installed. In 1935 few first „Babies“ as the new plane was widely nicknamed went to aeroclubs and MLL’s branches (MLL - Masaryk’s Air League organisation). They served reliably in training and by sporting touristic flying as well. British The Aeroplane weekly brought an extensive article about the new E 114 aircraft and spoke highly about its design and flight characteristics. In the second National Flight around Republic Czechoslovakia air race organised in September 1935 with a route measuring 1144 Km there were fourteen Praga Air Baby aircraft under fifty participants. In total classification the type E 114 took nine (9) first places with the exeption of the 6th place, which was the only one place taken by any other aircraft in this competition! The aviation public in whole Europe became interested in the E 114 aircraft. Soon even the commercial success came and production license rights for E 114 were sold to the British Messrs. Hillson company of Manchester.
In 1936, too, the „Baby“ continued with good reputation the type already gained. British airman H. L. Brook flew with the template aircraft made in Czechoslovakia (serving as model for the English license production) a route measuring 14 722 Km from Lympne in England to Cape Town in South Africa within 16 days and four hours. This was a new British national record for the light aircraft category. Soon the Praga E 114 attacked also on world records. In June of the same year a new world record in flight distance was created in the category of touristic airplanes with an empty weight of up to 280 Kgs by a flight on the route Cheb (Czechoslovakia) – Vilnius (Lithuania) measuring 1020 Km. By this the „Baby“ has had even some reserves in carrying load and engine power, so another attempt followed on quickly in August 1936, when two airplanes went from Prague to Moscow, U.S.S.R. on a route measuring 1680 Km. They were modified with auxiliary tanks for fuel and engine oil. With this their take-off weight was nearly 600 Kgs and the E 114 flew the route in severe weather conditions at an average speed of 115.2 Km/h and with hourly fuel consumption of 9.25 Litres. Still in 1936 the E 114 aircraft took part in both international stellar flights to the 11th Olympics in Berlin, Germany and to Siofok, Hungary. They won a pair of first two places in both competitions.
In 1937 a second series of E 114 aircraft was produced – now fully certified to the international CINA aviation standards. In July 1937 Praga E 114 Air Baby created two world speed records – 144.699 Km/h on the base measuring 100 Km and 144.148 Km/h on the base of 1000 Km. But in the end of 1937 the FAI technical rules for world records were changed. Until then the categories were measured by empty weight and the E 114 was classified in the first weight category of up to 280 Kgs, but by the new rules the categories were sorted by engine displacement (volume of cylinders), so the E 114 was now belonging into the second category of aircraft with engine volume of up to 2 Litres.
The last record flight of an „Baby“ before the Second World War took place on July 14, 1938 and went from Prague to Bagdad, Iraq, measuring some 3200 Km. By this an E 114 piloted by Capt. Polma took off heavily overloaded to an unbelievable T.O.-weight of 650 Kgs from the then new Prague-Ruzyně airport. The airplane overflew Istanbul and continued over Asia Minor (Anatolia) on a flight route set by Turkish government. But in this sector the „Baby“ was surprised by inclement weather. Capt. Polma had to choose – either continue in night storm over unknown mountainous terrain in a light plane without special blind flight instruments or return to Istanbul as long as it is still possible. The original goal was not reached, but the then valid French record was surpassed by 320 Km, as the route Prague-Istanbul measures 1560 Km.
114 Air Baby aircraft produced before the Second World War and from this number forty three were manufactured in Great Britain under Czechoslovak license. Three such Hillson-Pragas were even sold to far-away Australia. A small series was sold to Roumania by ČKD followed by sale of production rights. Some „Babies“ were sold to France, too, but the subsequent sale of production rights to that country fell thru as the war broke out. One E 114 aircraft was presented to Iran by the ČKD company. The last „Babies“ produced were sold to Slovak State, which was then an ally of nazi Germany.
In 1946 the Aircraft Department of ČKD company renewed the Praga E 114 series production mainly for the excellent flight characteristics and for economically modest operation. The design of „Baby“ was stiffened and further improved. The newly built airframes were powered by more powerful new Czechoslovak aircraft engines Praga D (appr. 10 aircraft) and Walter Mikron III (appr. 110 aircraft).
The „Babies“ produced after Second World War have not only changed in powerplant, but their design changed, too. They have got a new trapezoid form of vertical tail, the opening of cockpit cover changed, crew room was longer by 8 Cm, bigger was also the fuel tank, wing dihedral and the aircraft has gotten the lateral aerodynamic balance. Even the main undercarriage got the hydraulic brakes. The whole wooden airframe was manufactured from more solid but heavier beech plywood instead of the previous alder plywood used by pre-war E 114s. In the time-frame of 1946-1948 there were approximately 120 aircraft in few series. Some „Babies“ were sold abroad again – 10 airplanes went to France, others flew in Finland, Italy and Morocco. In the end of 1948 a control of fuselage strength with tow-glider attachment according to the British BCAR regulations was carried out successfuly and the „Babies“ started to tow gliders. In 1947 a Praga E 114 won in the first after-war international sport competition held in free Czechoslovakia „Blue Ribbon of the City of Zlin“. Abroad it won the 1st place both in „Air Rallye of Cannes“ and „Air Rallye of St. Etienne“, too. After 1948 the Republic Czechoslovakia went thanks to political changes into international isolation and the Praga E 114 was not further exported into democratic part of World. The type was unsuitable with its flight characteristics for the new paramilitary aviation training concept of sport pilots organised in newly created „Doslet“ and later „Svazarm“ paramilitary organisations. Thus the „Babies“ were soon mustered out and written off. In total there were approximately 220 aircraft of various Praga E 114 Air Baby produced, inclusive the pre-war British license manufacture. Some E 114 airplanes sold to western Europe flew until the Sixties. It can be said, that the type Praga E 114 is one of most successful aeroplanes of Czechoslovak design and the one and only such type, which was manufactured before and also after the Second World War.
This particular Praga E 114M construction number 122 was manufactured by the Aircraft Department of ČKD Prague company in 1947. Same as the majority of other E 114s produced after the war it was powered by Walter Mikron III engine. On September 11, 1947 it was duly inscribed into the Czechoslovak Civil Register with registration marks OKBGQ and was one of the ten airplane contract lot exported to France as FBCSQ. In the year 1952 it was sold to Switzerland and flew there with registration marks HB-UAD. Its flying career there ended modified by replacement engine Continental/Rolls Royce C90. Total flight time until 1987 logged was 1583 flying hours and number of 3640 take-offs. So it is possible to claim, that this particular one Praga E 114 aircraft is the oldest airworthy aircraft of Czechoslovak design and manufacture in existence.
|Sporting Successes of the Praga E 114 Air Baby
|Praga E 114 Air Baby C/N 122 in time:
|Walter Mikron III
|Walter Mikron III
|Walter Mikron III
|Continental A 65
|Continental/Rolls Royce C 90