El Aero A-100 series (incluyendo el Aero A-101 en España) parte 1

Este artículo está especialmente dedicado a Juan Millán, un modelador entusiasta de los aviones excéntrico y menos conocidas. ¡Que viva para siempre y espero que nos deleitará con su información muy informativo y chistes tontos por décadas por venir! Y Juan, por cierto, felicidades con su bonito construido "Lucky Seven". No deje que su alegría de vivir se infectan por un par de extremistas de derecha o de izquierda.

Un agradecimiento especial a este momento (por supuesto), Vladimir Nikiforov para compartir su colección de imágenes de eBay una vez más, a David Gesali para compartir una serie de bellas imágenes de LA-002 y (indirectamente) a Juan Arraez Cerda para el artículo informativo en Avions no 122.
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This item is specially dedicated to Juan Millan, a devoted modeler of eccentric and less-known aircraft. Let him live forever and I hope he will spoil us with his very informative information and silly jokes for decades to come! And Juan, by the way, congratulations with your beautifully built Lucky Seven.Dont let your joy of life get infected by a couple of right or left wing extremists.

Special thanks this time to (of course) Vladimir Nikiforov for sharing his collection of Ebay pictures once again, to David Gesali for sharing a series of beautiful pictures of LA-002 and (indirectly) to Juan Arraez Cerda for his informative article in Avions no 122.






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Seguramente no es el diseño más terrorífico de los años anteriores a la Segunda Guerra Mundial, ni la propuesta más avanzada de los departamentos de diseño a Checoslovaquia y ni siquiera el avión más maniobrable para volar. Sin embargo estos planos resistentes logró volar en una década. E irónicamente, el subtipo A-101 que fue rechazada por su fuerza aérea nativa, voló las misiones más en tiempos de guerra de todos ellos en la lejana España.

Sección 1: El Aero A-100 - Servicio de Desarrollo y en Checoslovaquia hasta 1937:
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Surely not the most terrifying design of the pre-WWII years, nor the most advanced proposal of the Czechoslovakian design-departments and even not the most maneuverable aircraft to fly. Still these sturdy planes managed to fly on for a decade. And ironically, the subtype A-101 that was rejected by its native air force, flew the most wartime missions of them all in faraway Spain.

Section 1: The Aero A-100 - Development and service in Czechoslovakia until 1937:

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Desarrollo de la A-100 fue en respuesta a un requerimiento de la Fuerza Aérea Checa de 1932 para la sustitución uniforme de la A-11, Aero Ap-32 y Letov S-16 entonces en servicio. De la configuración biplano estándar, la A-100 era un avión de aspecto desgarbado y algo obsoleto en el momento de su primer vuelo en 1933. Y un miembro de la última generación de aviones biplano militares que ser diseñado en Europa.
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Development of the A-100 was in response to a Czech Air Force requirement of 1932 for a uniform replacement for the A-11s, Aero Ap-32s, and Letov -16s then in service. Of standard biplane configuration, the A-100 was a ungainly-looking aircraft and somewhat obsolescent by the time of its first flight in 1933. And a member of the final generation of biplane military aircraft to be designed in Europe.

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Fotos 1-4: El Aero A-100 prototipo (A100.1), el código S22 se aplicó durante su programa de prueba final en el Instituto Militar de Aviación Checa, en Prostejov (VTLU).

Sin embargo, dado que el único competidor para el contrato de la fuerza aérea, la Praga E-36 (alias BH-36) no había volado por el cierre de las ofertas, la A-100 fue ordenado para la producción. Un total de 45 aviones fueron construidos: un prototipo y dos lotes de producción, respectivamente, 11 (A100.2 - A100.12) y 33 aeronaves (A100.13 - A.100-45). El primer lote fue entregado entre julio y octubre de 1934 y asignado a la 71 ª y 72 vuelos de la 1 ª Regimiento de aire.
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Pictures 1-4: The Aero A-100 prototype (A100.1), the code s22 was applied during its final test program at the Czech Military Aviation Institute at Prostejov (VTLU).

Nevertheless, since the only other competitor for the air force contract, the Praga E-36 (alias BH-36) had not flown by the close of tenders, the A-100 was ordered for production. A total of 45 aircraft were built: one prototype and two production batches of respectively 11 (A100.2 A100.12) and 33 aircraft (A100.13 A.100-45). The first batch was delivered between July and October 1934 and assigned to the 71st and 72nd flight of the 1st Air Regiment.

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Pictures 5-12: Pictures and profiles of aircraft of 71st and 72nd Flight of 6th Air Regiment.

The second batch of 33 aircraft were delivered between January and may 1935 and were divided between the other flights of the Czechoslovak Air Force mentioned in the table shown below:

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Pictures 13+14: Two profiles of A-100s of 66th Flight of the 1st Air Regiment.

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Pictures 15-17: Aircraft of 66th Flight of the 2nd Air Regiment

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Pictures 18-22: The K10 and K11 of 64th Flight of the 3rd Air Regiment.

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Pictures 23-26: The A-100s delivered to the Central Flying School were fitted with dual controls.

The A-100 was an unequal-span biplane with a steel-tube fuselage and wooden wings, armament comprised a pair of fixed forward firing 7,92 mm Vickers machine guns and for the observer a pair of Lewis guns. The bomb load of 600 kg could be carried partly vertically in a forward fuselage bay and partly horizontally on external racks.

Power was provided by a Avia Vr-36 (license-built Hispano-Suiza 12Nbr) 12 cylinder liquid-cooled engine of 740 hp maximum (650 hp nominal) output, see picture 27 below:

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One Aero A-100 (A100.28) was experimentally modified for night flying, but these modifications were not implemented on any other production aircraft, see picture 28 below:

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When on the 15th of March the German Wehrmacht occupied Bohemia and Moravia, the Czechoslovakian Air Force was dissolved and a number of A-100 and A-101 reconnaissance biplanes and their light bomber counterpart, the Ab-101 were seized by the Luftwaffe for training purposes. Altogether some sixteen A-100s and Ab-101s were handed over to the newly created Slovakian Air Force and ten of them still served in the 6th Flight on the 1st of January 1940.

Section 2 - The Aero A-100 in Luftwaffe service:

Almost nothing is known to me about the use of the Aero A-100 in Luftwaffe service, only that they were operated by one or more FFSs (Flying Schools). There is a lot of speculation about where and by what units. Maybe Dusan Slezak can provide us some facts from Czech or Slovak publications.
The only proof I have are a couple of pictures, unfortunately without any readable identification codes.

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Pictures 29-30: Aero A-100s of the Luftwaffe. Although the engine of the Aero in the second picture is covered, I dont see any protruding exhausts on the upper side of the cover, so I suppose this is a A-100 as well.

Section 3 The Aero A-100 in the Slovakian Air Force.

As told before, some sixteen A-100s + Ab-101s were handed over to the newly created Slovakian Air Force (under Luftwaffe patronage) and were assigned to the 3rd Air regiment (Letecky Pluk 3), 6th Flight.
In the second half of 1939 the S.A.F. made a few desultory attacks on Polish targets in support of the Luftwaffe, including a bombing raid on Tarnopol. The combination of obsolete aircraft and a total lack of enthusiasm on the part of the Slovak aircrews produced predictable unimpressive results. As far as I know no A-100s took part on these assaults. From then on all A-100s were only used for training purposes. In the course of 1942 the obsolete material of the Slovak Air Force was replaced by more modern German equipment and on the 1st of January 1943 there was no more A-100 in its inventory.

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Pictures 31-36: A-100s in different Slovak Air Force schemes.

Section 4 The Aero A-101 - Development and service in Czechoslovakia until 1937:

The A-101 was a further development of the A-100, featuring increased wing span, enlarged rudder and most important a more powerful engine: the Praga built Isotta-Fraschini Asso-1000 18-cylindir liquid-cooled W-engine of 1000 hp maximum (800 hp nominal) output. Because there was a surplus of these engines, it seemed to be a good idea to use these engines for a more potent version of the A-100. The prototype first flew in December 1934 and a production line of 30 pieces was started alongside the second batch of A-100s. The last aircraft of these series were taken over by the Air Force in January 1936 and the aircraft were assigned to the 6th Air Regiment.

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Pictures 37-39: Plans of the A-101 and a picture of its heavy 18-cylinder W-engine.

During its test program at the Czech Military Aviation Institute at Prostejov (VTLU), the prototype (coded s23) proved to be far from satisfactory. The very heavy engine was unsuited for its air frame, overall performance was very disappointing, and even flying characteristics were inferior to those of the A-100. So the Czechoslovak government lost total interest in the project and was very relieved to get rid of this type when the Spanish government showed interest and even offered to purchase some fifty A-101s.

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In early 1937, when the Spanish order had to be fulfilled, there were still 28 fully serviceable A-101s in the inventory of the Czechoslovakian Air Force.

Pictures 40-44: The first A-101 (A101.1) prototype alias s23, and A-101s serving with the 71st and 72nd Flight of the 6th Air Regiment.

Section 4 The Aero A-101 in Spanish skies:

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Pictures 45-52: Pictures of the first shipment of Aero A-101s to Spain, respectively 17-1, 17-3, 17-8(2x), 17-9, 17-10 and 17-11.

Most sources contradict each other in mentioning numbers and types of Aeros delivered to Spain.
For instance Gerald Howson is mentioning a total of 47 aircraft in his book Aircaft of the Civil War 1936-1939 (ISBN 0-85177-842-9 - 1990) and I quote some sentences here:
On the 8th of April 1937 the first 22 Aero A-101s left the Polish port of Gdynia on board the Hordena, The Hordena, however, was captured by the Nationalist cruiser Canarias in the bay of Biscay on 16 april 1937, and, after assembly, the Aeros were formed into two escuadrillas of the Spanish Nationalist air arm.
Meanwhile, 16 Aero Ab-101s (Hispano-Suiza 12Ydrs V-engines rated at 725 hp) arrived in the Republican zone during the summer of 1937 and were assembled in an underground workshop built in caves near Madrid. Bearing the type code LN (or LA according to some sources), they took part in their first action during the battle of Belchite in August 1937.
A third batch of 9 Aeros, probably A-101s, arrived in France during the summer of 1937 and was impounded by the French authorities. When the Franco-Spanish frontier was opened from 19 March to 13 June 1938, however, they were allowed to cross into Spain and were assembled at Figueras, in Catalonia, in May.

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Pictures 53-61: Some more pictures of the first shipment of Aero A-101s to Spain, respectively 17-12(2x), 17-13, 17-14(2x), 17-15, 17-16, 17-20 and 17-22.

Our dear friend Juan Arraez Cerda, however, mentions a total of 28 aircraft (all A-101s) in the 2003-05 issue of Avions (no 122): the 22 delivered by the Hordena and 6 aircraft that were impounded by the French authorities.

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Pictures 62-70: Other pictures of Nationalist A-101s without recognizable serial numbers, the last showing six A-101s gathered together by the Nationalists for the Barajas air-show after the end of hostilities in May 1939.

As a complete outsider, but due to the fact that the Czechs could only deliver a maximum of 28 A-101s (see section 3) and because I have never seen a picture of a Spanish Ab-101 (different airframe, different engine, see section 5), nor have seen any sources mentioning the delivery of these aircraft, I tend to believe that Juan is completely right.
And because Juans article is very informative, also mentioning the operational use of the A-101s to which I have little to add, I hereby give the links to download this fine issue:

http://rapidshare.com/files/56277796/avions122_b.part1.rar.html
http://rapidshare.com/files/56278832/avions122_b.part2.rar.html

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Pictures 71-78: Most, so not all of these pictures of the Republican A-101 LA-002 are taken during a propagandistic photo session at La Señara. Photos at other locations or from different Republican A-101s are unknown to me.

There are no records of any surviving Republican A-101s, but the Nationalists renovated 16 of their own after the war and in March 1940 thirteen were still in the inventory of the Ejercito del Aire. All A-101s were withdrawn from service by 1946.

Section 5 The Aero Ab-101 - Development and service in Czechoslovakia until 1937:

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After the sale of their A-101s to Spain, the Czechoslovakian Air Force was faces with the fact of having too little operational/training aircraft for their light bomber component and the development and delivery of more modern equipment (A-300 and B-71) would last for years to come. So the decision was made to put a modern Praga built Hispano Suiza 12Ydrs (for instance the standard engine for the Avia B-534) in the redesigned Aero airframe as a stop-gap. So the Ab-101 was born, the prototype was flown in September 1935, an order was placed for 64 production aircraft, and production continued until 1937.

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Pictures 79-82: Pictures of the J11 of the 71st Flight of the 6th Air Regiment,and the H9 and H10 of the 75th flight of the 5th Air Regiment.
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According to the Order of Battle at 1 September 1938, at least the following units were equipped with the Ab-101:

5th Air regiment:
Flight 75, (kpt. Vladimir Pál) Nitra Aero Ab-101
Flight 76, (kpt. Miroslav Prochazka) Brno Aero Ab-101
Flight 77, (Charles kpt. Dóczy) Brno Aero Ab-101

6th Air Regiment:
Flight 71, (Mjr. Philip Dolezal) Prague-Kbely Avia B-71 (SB) & Aero Ab-101
Flight 72, (Kpt. Emil busin), Prague-Kbely Avia B-71 (WB) & Aero Ab-101
Flight 73, (Ota kpt. Groff) Hradec Kralove Aero Ab-101 & Avia B-71 (SB)
Flight 74, (Vaclav kpt. disgusting) Hradec Kralove Aero Ab-101 & Avia B-71 (SB)

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Pictures 83+84: Pictures of the N7 of the 73rd Flight of the 6th Air Regiment.

After the German occupation most the Ab-101s were were seized by the Luftwaffe for training purposes and some were handed over to the newly created Slovakian Air Force

Section 6 The Aero Ab-101 in Luftwaffe service.

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Pictures 85+86: An Ab-101 of Sch./RAR33 with very crude swastika.

Very little is known about the use of the Ab-101 with several Luftwaffe training schools, nor when these aircraft were replaced by more competent German designs. Maybe some Czech, Slovakian or German readers can provide us some more facts about this subject. The only hard facts I have are some pictures of Ab-101s in Luftwaffe colors and I will show these below without any comment, speculations or assumptions.

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Pictures 87-93: Pictures of Aero Ab-104s used by the Luftwaffe, for instance by FFS A/B 113 and 116.

Section 6 The Aero Ab-101 in service with the Slovakian Air Force.

Altogether some sixteen A-100s and Ab-101s were handed over to the newly created Slovakian Air Force and ten of them still served in the 6th Flight on the 1st of January 1940.
At least one Slovakian Ab-101 (together with two Letov S-328s) managed to escape to Poland on the 7th of June 1939, three months after the Slovakian Air Force was created and three months before the German attack on Poland in September the same year.
Shortly after the Germans had occupied Dblin airport, the next picture was taken. Surprisingly, the Aero shown here, still wears its former Czechoslovakian markings, but to my opinion, this has to be the same aircraft.

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Section 6 The Aero A-104, the last variant of the Aero A-100 series.

Of course, the Aero factory was fully aware of the unsatisfactory performance of their A-100 , A-101 and Ab-101 biplanes. Therefore the project A-100B was started in the mid-thirties, basically a redesigned A-100 to a mostly metal high strutted monoplane configuration. wing which featured A-100 reprocessing Strutted the high-wing metal frames with wings. Development of this proposal was refused by the Czechoslovakian Air Force until 1936, realizing that more modern types of aircraft could not being delivered before 1939.

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Pictures 94-96: The prototype of the Aero A-104, the last one during its final tests at the Czech Military Aviation Institute at Prostejov (VTLU), coded s25.

In 1936 an order was placed for a prototype. Changes in the implementation of the original proposal contained the use of an almost unchanged Ab-101 fuselage including the Hispano Suiza 12Ydrs and an enclosed cockpit configuration
The prototype successfully completed its military test program in the first half of 1938.Performance was much better than that of the former Aero biplanes, but unfortunately, a delay in development in conjunction with the introduction of the B-71 caused the cancelation of further development and production.

Sources:

Janes all the worlds Aircraft 1938 ISBN 0 7153 5734 4: Pictures 1, 6,
www.rujet.ru website: Pictures 2, 4,
Avions no 118 (France) ISSN 1243 8650 (2003-01): Pictures 3, 5, 8, 9,16, 17, 20-23, 26,33,
Vzduch Je Nase More - Ceskoslovenske Letectvi 1918-1939 ISBN 80-206-0221-6: Pictures 7, 31, 42, 44, 48, 82-83,
http://wp.scn.ru Wings Palette website: Pictures 10, 19, 46, 76,
Aircam Aviation Series no S5 Czechoslovakian Air Force 1918-1970 SBN 85045 021 7: Pictures 11, 43,
Avions no 119 (France) ISSN 1243 8650 (2003-02) Pictures 12, 13, 18, 24-25, 27-28, 34,
Transpress - Tschechoslowakische Flugzeuge von 1918 bis heute ISBN 3-344-00121-3: Pictures 14,
http://www.fronta.cz website: Pictures 15,
http://www.luftwaffe-experten.org/forums/index.php?act=idx - Luftwaffe Experten Message Board website: Pictures: 29, 79, 87, 91,
Ebay Germany: Pictures 30, 53, 61, 64,
http://vinar.cz website: Pictures 31, 40-41,
Magnet Press Slovakia Slovenské Letectvo 1939-1944 ISBN 80-968073-2-3: Pictures 35-36,
L+K 20-88 Monografie Aero A-101: Pictures 37-38,
My scrapbook: Pictures 39, 55, 80, 84,
Avions no 122 (France) - ISSN 1243 8650 (2003-05) Pictures 45, 47, 51, 54, 56-58, 62, 68, 71,
Negro Daniel via Aeronet GCEhttp://www.network54.com/Forum/394728 : Pictures 49,
Putnam Aircraft of the Spanish Civil War 1936-1939 (ISBN 0-85177-842-9): Pictures 50,
Revista Aeroplano (ISSN 02-12-4556) no 5: Pictures 52, 67, 69,
Vladimir Nikoforovs archive: Pictures 59, 65-66, 69,
V nebe Ispanii 1936-1939 (Russia) by Sergei Adrokov: Pictures 60,
M.R. Valverdes website http://usuarios.lycos.es/mrodval) : Pictures 63, 70, 77-78,
David Gesali via Aeronet GCEhttp://www.network54.com/Forum/394728: Pictueres 72-75,
Valka.cz forum http://forum.valka.cz/ ): Pictures 81, 94-96,
Revista REVI no 49 (ISSN 1211-0744): Pictures 85-86, 92-93,
Air Warfare Forum (not existing anymore): Pictures 88,
Waffen Arsenal no 071 Fremde Vogel unterm Balkenkreuz (ISBN 3-7909-0157-1): Pictures 89,
Hikoki - Luftwaffe Fledglings 1935-45 Luftwaffe Training Units Their Aircraft (ISBN 0 9519 899 2 8): Pictures 90,

Cheers, Peter