AVIA was formed after the Great War (WWI) working closely with Skoda's aviation section, and finally in 1931 it took all the means of the latter.

-The most prolific period was in the 1930's, as they continued with many Skoda engines.

-They also built engines under license, mainly European (especially Hispano Suiza).

-And the American Wright Whirlwind, of which they made about 300 engines in 1935/39.

-After WWII, they continued as Avia, in some kind of National Corporation due to the new régime, the “Automobilove Zabody, Narodni-Podnik”. (with Letecke Zabody).

-Besides inherited and own designs, during times of close relations with Russia, they manufactured engines under license from this country.

-Currently the three brands existing in the Czech Republic and Slovakia, Avia, Danek, and Walter have been absorbed by the German engine industry, so Avia in Prague-Cakovice went to Skoda-Volkswagen, Kolben-Danek to BMW-AG ( BMM-AG?) and Walter to Argus in Germany.

-Unable to follow a strict chronological order, we go over the engines that came to us as Avia.

"Avia DFTr"

-The DFTr was a horizontally opposed boxer type engine that gave 45 CV, with gear as the crankshaft ran at 3,160 rpm and the propeller at 1,580 rpm.

“M-137"

-The inline inverted engines that now rampant with names like Motorlet, etc. from Czechoslovakia itself, and installed in aircraft like Morava o Zlin, were built under Walter license, so the inverted 4-cylinder Walter Minor was the Avia M-132 that gave 121/138 CV.

-And its 4-cylinder variant M-332 giving 140/207 CV.

"M-332"

-The M-137 and the M-337 were designs from the 1930’s, and they are still built in various versions today.

"M-137A"

-The M-137A is supercharged and is mounted in the Zlin-526 and 42M, fully acrobatic.

-The M-137AZ includes a special air filter for dusty areas.

-The M-337As were supercharged and were installed in the Zlin 43 and 726K.

-The M-337AK version was installed in the Zlin 142.

"M-337"

-The M-437 engine was just like the M-337, but with gear and running at 3,440 rpm instead of 2,750 rpm.

-Going back a little, Avia also built horizontally opposed engines like the 6-cylinder M-108H that gave 240 CV, and the 4-cylinder M-110.

-The M-150 with 4 horizontally opposed cylinders (1932) gave 45 CV at 3,000 rpm.

-There was a two-stroke engine that was known as Jawa and was used in gliders and similar devices.

"Jawa"

-An interesting production period is when they built Hispano Suiza engines under license.

-They also built under license Lorraine engines and their derived ones, and the genuine Avia-Skoda “L”.

-Between 1935 and 1939, besides building the mentioned 300 Whirlwind engines, Avia manufactured the Hispano Suiza 12-cylinder V engines.

-The Hispano Suiza HS-12-Nbr was built under Avia name V-36, giving 725 CV. The HS-12-Ydrs under the name Avia AB-30, and the HS-12-Ycrs as Avia AB-35.

-A nice Avia 12Y-31 engine is exposed at the Air Museum in Le Bourget in its engine reserve storage.

"AVIA - Hispano Suiza 12Y-31"

-The front, with an inner section of the gear at sight, is showed in the following photo. Carefully sectioned, you cannot get lost.

"AVIA - Hispano Suiza 12Y-31"

-From the several versions of the Hispano-Suiza 12Y built at AVIA, we now have some photographs of the twelve-cylinder V 12Ydrs engine, which was used on aircraft made in Czechoslovakia.

“Avia 12Ydrs”

-The Tupolev SB-2 aircraft, which were built in Czechoslovakia, used the Avia AB-30 models that were derived from the HS-12-Ydrs.

"Avia AB-30"

-That manufacture under license did not prevent them from building genuine engines like the Avia V-30 12-cylinder V engine. This engine had the V at 45° and delivered 700 CV.

"Avia V-30"

-The "W" model engine was inherited from Skoda in 1931 and it was known as the "L" model.

-It was a fan-shaped engine with twelve cylinders in three rows of four, which could have direct transmission or reduction gear.

-The cylinder blocks were similar to those of the Hispano Suiza V-8 engines. Its power was 500 CV at 2,000 rpm.

"Avia L"

-The 18-cylinder W-44 "W" engine was a similar, but more developed like the Lorraine engines. It delivered 1,000 CV.

"Avia W-44"

"Otra vista del W-44"

-Now we enter the land of radials. We start with the smallest available, the R-7, a 5-cylinder radial engine that gave 120 CV.

-From the R-10 we know that it also had 5 radial cylinders, and gave 170 CV at 1,850 rpm.

-The R-12 was a radial 7-cylinder engine that gave 200 CV, and was used by the Avia 51 aircraft.

-The DR-14 was a double R-7 and gave 250 CV.

"Avia R-7"

"Foto invertida del R-7"

-The photo published in a Polish booklet, in which the R-7 engine is showed upside down, with the Skoda logo (bottom right) and inverted carburetor. The upper cylinder inadequately on the lower part.

"Avia R-12"

"Avia R-14"

-The RK-17 was the 9-cylinder version of the 7-cylinder RK-12. It gave 420 CV and was used by the Letov 550.

"Avia RK-17"

-We see it from the rear. The DR-20 as indicated by its reference, was a double row radial engine (DR) that gave 350 CV. Basically two coupled R-17.

"Avia DR-20"

-The R-29 was a 9-cylinder radial engine that gave 500 CV to 600 CV.

-In the USSR relationship period, engines are manufactured under license like the Ivchenko AI-14RF that gave 305 CV. It was a 9-cylinder radial engine with gear and supercharger. Somewhat changed.

-This engine was known under the name M-462 RF.

"Avia R-29, two views"

"Avia M-462"

-After WWII Avia built the BMW 109-003A engines like the M-03 (and the M-04 in Czechoslovakia).

-Remains of a battered little Avia M-04 engine, which was built to be installed in the Me-262 aircraft that was built in Malesice.

-This was a copy of the German BMW-003 engine.

"Front view of an M-04"

From appendix 7: For the Avia 12Ydrs model (under license Hispano-Suiza) they made a different circuit for the lliquid-cooling. It always depends on the type of aircraft and its adaption.

"AVIA 12Ydrs"

“Cool circuit” (PiP)

-A large unique radiator and fuel supply tank between the cylinder blocks.

-From appendix 9: During WWII, the DB-603 were also built in Prague.

-In the main text, we mentioned a horizontally opposed, four-cylinder engine, model M-110H. We have located one at the Norodni Museum in Prague.

"Faired helicopter engine"

-In the Praga chapter this engine is also mentioned as DH engine.

-This "Praga" inscription is also shown on this same engine on the cylinder head covers. But there is an enigmatic plate having a logo that indicates "PAL", which we show too.

"Covers with the Praga inscription"

"Engine plate with the PAL logo"

"Another view of the Avia M-110H"

-Avia also had similar references like M-108 and M-150.

From appendix 9: Also see Skoda. In addition to what is mentioned in the main text, we list the following engines:

"Avia -Skoda- HS 8Fb, year 1922"

"Avia -Skoda- HS, model L -y Lr-, year 1924"

"Avia V-30, year 1932"

"Avia W-44, year 1932"

-The V-36 and Vr-36 from the year 1931 delivered 740 and 760 CV and were V-12 engines.

"Avia -Hispano Suiza 12 Ydrs (y Ycrs), year 1935"

"Avia boxer DFTr, year 1931"

"Avia R-7, year 1930"

-The DR-14 and DR-20 models are two-row radial engines from 1930. They are small ones that deliver 170 and 350 CV at 1850 rpm, while at cruise speed.

Hispano-Suiza-The R-10 is from 1930, and has 7 radial cylinders.

The R-29 (and Rr-29), from 1932, with 9 radial cylinders giving 600 CV at 2,000 rpm, while at cruising speed.

"Avia R-29"

"Avia Rk-12, year 1933"

"Avia Rk-17, year 1934"

From appendix 10: At the Prague Museum there is an RK-12, which is an R12 variant.

"Excellent picture of the Avia RK-12"

-Avia RK 17 9-cylinder factory pictures (larger version of the 7-cylinder RK-12).

"Double Illustration of the RK-17" (Factory Photo)