hesham

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Hi,

we can speak here about CKD-Praga early Projects,and that was a drawing to early Praga E-112 Project drawing
from 1938,as a light and trainer low-wing monoplane,after WWII,the aircraft built in a different shape.

L+K 8/1975
 

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Hi,

The three-seat bomber E-48 was designed in reply to the tender for the Type IV (Type IV - multi-place day/night light bomber, one of the four categories of aircraft required by the Czechoslovak Ministry of Defense). Developed in July 1936, it was to be powered by two 925 hp Hispano Suiza 12YZ1 engines. The large central gondola would have had one machine gun in the nose, and another for defence in rear dorsal position. The aircraft structure was to be based on a wood and steel scructure . In the lower section of the gondola was a bomb bay for up to 1000 kg of bombs and up to two 200 kg bombs could be carried under the centre section of the wings. Besides the overall dimensions there are available some weight and performance data:
span 19 m,
length 13,4 m,
height 3,95 m,
empty 3650 kg
maximum take-off weight 5772 kg
max airspeed 440 km/h
cruising speed 395 km/h
operational range 790 km

From: Československá letadla vol.1 V.Něměček, Československé prototypy 1938 vol.2 Jakab Publishing and my speculative drawing.
Praga E-48.jpg Praga E-48_.png Praga E-48_0.png Praga E-48_1.jpg
 
Hi,

The Praga E-48 evolution is evident from the original model for wind tunnel testing, with a single-fuselage and a variation on the tail configuration.

From: Československé prototypy 1938 vol.2 Jakab Publishing and my speculative drawing.
Praga E-48_4.jpg Praga E-48_2.jpg Praga E-48_3.jpg
 
Hi,

A study of the Praga BH-48 fighter aircraft of 1933, powered by a Praga CRK engine of 650 hp. Estimated wingspan 10.6 m, length 8.0 m...
Engineer Šimůnek was involved in the development of the Praga CRK engine, and as he is an important figure in the design of Czechoslovak piston engines, I will dedicate a few sentences to him.

After his studies at the Czech Technical University he joined Avia in 1929, where he briefly headed the static department, and in 1933 he moved to ČKD-Praga, where he joined as a designer. He was involved in the development of the twelve-cylinder, water-cooled Praga ES, ESVK, CRK engines, which were modern engines for their time with extensive use of aluminium and later electron, especially for the crankcase. His first independent designs were the 36 hp Praga B-2 and 85 hp Praga D aero engines for sport aircraft.

In 1938 he joined Walter, where he was involved in the development of the world-famous Minor and Mikron series engines. In 1947 he came up with a new line of Walter engines, designated the Walter V series. The first engine in this series was the Walter M-431 (Walter Mc). This was followed by the Walter V-12 (M-446) inline 12-cylinder engine with a V-cylinder arrangement and a takeoff power of 700 hp. The last unrealized engine was the Walter V-6 (M-436) inline six-cylinder engine. Its development had been underway since 1949 and was terminated the following year without a single prototype being built. Power was estimated at 320 hp.

In the 1950s, there was no interest in the development of piston engines in Czechoslovakia (a political decision that had fatal consequences for the further development of these engines).It was only in the second half of the 1950s that engineer Šimůnek pushed for the production of innovative piston engines. The Minor 4-III engine was modified in 1956 to the M-332Sc 140 hp version with switchable turbocharging, low-pressure injection before the intake valves (MPI, Multi Point Injection), OHC timing and electric starter, and in 1959 serial production of the upgraded Minor 6-III engine in the M-337Sh 210 hp version was started. In 1959, the M-332Sc engine was modified to the M-332Sc 140 hp version.

A total of 3,092 Walter Minor 4-III four-cylinder engines were produced in 1946-1960 and a total of 1,192 M-332 engines (1956-1964). There were 1,508 six-cylinder Minor 6-III engines produced in 1947-1963 and 1,147 M-337 engines in 1960-1964.

In 1958 the development of Walter engines was transferred to Avia. Engineer Šimůnek continued the design at Avia and in 1970 the Avia M337A engine was introduced into production and finally in 1980 the Avia M337AK. Between 1964 and 1992, over 2000 of these engines were produced at Avia...

From: Československá letadla vol.1 V.Něměček and my speculative drawing.
Praga BH-48.jpg Praga CRK.jpg Praga BH-48_.jpg
 
I'm intested in the Praga CRK engine. Do you happen to know displacement, bore and stroke?
 
Hi,

The Praga E-451 study was a conversion of the E-45 type into a monoplane. Estimated wingspan 10 m, length 8,5 m, engine probably Hispano Suiza HS 12 Ydrs.

The author of this study was - as with the original Praga E-45 - ing. Jaroslav Šlechta. The length of the E-45 type was 7.45 m, wingspan 8.5 m and total area 20.25 m²; take-off weight was 1691 kg. The engine was a weakness - the HS 12 Ydrs engine could not be found, so a weaker Rolls-Royce Kestrel VI was installed. The maximum speed of the machine was 372 km/h, maximum altitude 9500 m above sea level and range 640 km. Armament consisted of two 7.92 mm machine guns. The prototype flew for the first time on 8 October 1934 and despite the weaker engine, it did not perform badly. However, the choice fell on a competing machine, the Avia B-534, which first flew in May 1933 and had more powerful armament. The Praga E-45 was chosen at least as a back-up solution in case the Avia B-534 did not prove itself after all. This did not happen, however, as the aviation department of ČKD-Praga found itself in considerable economic difficulties for a time and the E-45 prototype was the only example of this machine produced.

From: Československá letadla vol.1 V.Něměček and my speculative drawing.
Praga E-451.jpg Praga E-451_.jpg Praga E-45.gif
 
Hi,

The Praga E-46 study. Chief engineer Šlechta completed this project in April 1934. It was to be a wooden upper biplane with side-by-side seating in an uncovered cabin and was to be powered by an Aeronca E-113 A (36k) engine. The E-46 design was not final, with further modifications the project crystallized until the first drawings of the final version began to be drawn in June 1934. The new concept envisaged an all-wood wing attached to the upper fuselage. The fuselage was also all-wood with a fully covered cockpit. In this form, the project was considered mature. Thus was born the Praga E-114, one of the most widely used and popular Czechoslovak pre-war aircraft...

From: Československá letadla vol.1 V.Něměček and my speculative drawing.
Praga E-46.jpg Praga E-46_.jpg
 
Hi,

the Praga E-49 study from 1936-37. Estimated wingspan 11.0 m, length 8.9 m, two inverted six-cylinder Praga ARK engines equipped with compressor and reducer, power 220-300 hp.

From: Československá letadla vol.1 V.Něměček and my speculative drawing.
Praga E-49.jpg Praga E-49_.jpg
 

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Was the Praga E-49 a two-seater? Just wondering given the rear canopy section looks like its suitable as a dorsal gunner position.
 
Was the Praga E-49 a two-seater? Just wondering given the rear canopy section looks like its suitable as a dorsal gunner position.
Hi,
the shape of the cockpit makes it look like that. On the other hand, the overall dimensions and engine performance don't suggest that. In my opinion, this project fell into the same category as the Praga E-52 (light fighter aircraft). No mention of the type in the book, just this sketch...
 
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Hi,

the Praga E.50 study was a response to the 1936 MNO (Czechoslovak Ministry of Defence) request for a two-seat fighter and combat aircraft (Type II). Estimated wingspan 10.4 m, length 8.0 m. Propulsion would probably be provided by a Hispano Suiza HS 12y engine...

From: Československá letadla vol.1 V.Něměček and my speculative drawing.
Praga E-50.jpg Praga E-50_.jpg
 
Hi,

The Praga E-53 (1939) was designed according to the specifications of the Ministry of National Defence (MNO) and corresponded to the Type IV category (multi-seat light bomber day and night aircraft). It was a direct competitor of the Letov Š.43 and Aero A-300 (which was the only one built and flown in prototype). Estimated dimensions. Wingspan 18.6 m, length 13.0 m. Propulsion was to be provided by Rolls-Royce Peregrine engines. ČKD-Praga wanted to license these engines, as well as the Rolls-Royce Merlin type, for introduction in Czechoslovakia.

From: Československá letadla vol.1 V.Něměček and my speculative drawing.
Praga E-53.jpg Praga E-53_.jpg
 
Hi,

For the upcoming licensed production of Rolls-Royce Merlin engines (reportedly there was one example of this engine in ČKD-Praga), chief designer Šlechta developed a design for the Praga E-55 fighter aircraft in 1937. Estimated wingspan 10,6 m, length 8,5 m.

From: Československá letadla vol.1 V.Něměček and my speculative drawing. Praga E-55.jpg Praga E-55_.jpg
 
Hi,

study of the Praga E-60 observation aircraft from November 1938. It was to be powered by a ZOD-260 engine (300 hp). Estimated dimensions, wingspan 14,5 m, length 8,6 m. The inspiration of the Westland Lysander is obvious...

From: Československá letadla vol.1 V.Něměček and my speculative drawing. Praga E-60.jpg View attachment Praga E-60_.jpg
 
Hi,

the Praga E-112 study has undergone an interesting evolution. The first study with this designation was created in 1934 and was intended to be a modernization and simplification of the Praga BH-111 sport aircraft. A four-cylinder Walter Junior engine (120 hp) was chosen for propulsion. In 1938 the project matured into the form shown in the sketch in the magazine L+K 8/1975. During the war the project was again shelved, but in 1946 engineer Šlechta returned to it and in a revised form it crystallized into a prototype that took part in the MNO (Ministry of National Defence) competition for a new trainer. The competition was won by the Zlín Z-26 type, so the Praga E-112 remained only in the form of a prototype.

From: L+K 8/1975 and my speculative drawing.
Praga E-112.jpg Praga E-112_.jpg Praga E-112.gif
 
Hi,

study of the Praga E-250 four-seater aircraft from 1937. Propulsion was provided by a flat four-cylinder Praga DR (variant with reducer) with 85 hp. Estimated wingspan 12.5 m, length 8.5 m.

From: Československá letadla vol.1 V.Něměček and my speculative drawing.
Praga E-250.jpg Praga E-250_.jpg
 
Hi,
type number E-46 was occupied by chief designer Šlechta twice. The first time it was for this conceptual predecessor of the E-114 type https://www.secretprojects.co.uk/threads/praga-early-projects.31893/post-464805, but later Praga introduced the designation for sport aircraft (from 111 upwards), and so the number 46 was again released for military types. In March 1935, it was occupied by a light fighter project - a single-seat biplane. The E-46 type was to be powered by two air-cooled Praga ARK inverted engines (300 hp) and was to be armed with four machine guns. Wingspan 9,53 m, length 7,15 m. Flight weight 1 800 kg, maximum speed 365 km/h.
Source: the Bittner Collection of the NTM Prague
Praga E-46.png
 
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Hi,
chief designer Šlechta returned to the concept of a twin-engine light fighter aircraft twice. First with the E-46 biplane of March 1935 and then the two-seater Praga E-49 of November 1935. In this type, the engine axes were close together, concentrating the thrust of the engines to the axis of the aircraft. Armament consisted of two 20 mm calibre cannons, two Praga ARK inverted inline engines of 300 hp. Wingspan 11 m, length 7,6 m, flying weight 2100 kg, maximum speed 430 km/h, range 8000 m, range 750 km.
Source: Bittner Collection of the NTM Prague
Praga E-49.png
 
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Hi,
more information about the Praga E-49 project. There were two variants of the project. Variant 1. Wingspan 11.0 m, length 7.65 m, flight weight 2100 kg, maximum speed 430 km/h, range 750 km.
Praga E-49_.png
Variant 2. Wingspan 12.3 m, length 7.5 m, flight weight 2200 kg, maximum speed 430 km/h, range 800 km.
Praga E-49-1.png
Source: Bittner Collection of the NTM Prague
 
Hi,
project Praga E-55, one of two variants. This one dates from August 1937. At the time Praga was in talks to introduce licensed production of the Rolls-Royce Merlin engine (specifically the Merlin II), and so this engine was to power the E-55 project. Wingspan 10.5 m, length 8.85 m. No other technical data survives.

Source: Bittner Collection of the NTM Prague
Praga E-55-2.png
 
Hi,
The Praga E-55, the first of two variants, dates from February 1937. It was powered by a 1000 hp Grome-Rhone 14 N engine at 4000 m altitude, manufactured in Czechoslovakia under license from Walter. Wingspan 9.8 m, length 7.2 m. No other technical data survives.

Source: Bittner Collection of the NTM Prague
Praga E-55-1.png
 
Hi,
The Praga E-55, the first of two variants, dates from February 1937. It was powered by a 1000 hp Grome-Rhone 14 N engine at 4000 m altitude, manufactured in Czechoslovakia under license from Walter. Wingspan 9.8 m, length 7.2 m. No other technical data survives.

Source: Bittner Collection of the NTM Prague
View attachment 694436
Is it just me or is this giving the feeling of the love-child of a P-43/47 and an F4U!!
 
Hi,
the Praga E-48 project has undergone an interesting evolution. This is the first of three variants. Dating from December 1935, it was to be a light bomber powered by two 450 hp Walter Super-Castor radial engines. Calculated performance was insufficient, so this variant was abandoned. Wingspan 18 m, length 14 m. Other technical parameters have not been preserved.

Source: Bittner Collection of the NTM Prague
Praga E-48-I.png
 
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Although the two variants of the E.55 listed above are separated by 7 months, I wonder if there was any versions between these, which may have utilised features of both designs, ie the gull wing with perhaps the Merlin as per this what if, I drew up of the profile view. I will add that there may have been C of G issues due to the change from the shorter radial to the inline powerplant so this is not a definitive of what it may look like. E.55 What if profile of between variant.jpg
 
Hi,
The Bittner collection lists only the two versions of E.55 described above. The introduction of the RR Merlin engine license in Czechoslovakia would still take some time, so in my opinion this version was rather hypothetical. The Grome- Rhone 14 engine (version K) was already physically produced by Walter at this time (1934 onwards), so switching to another version would not have been a problem, and so a version with this engine would have been far more realistic.
 
Hi Sarastro, given your comments above, that leads me to something like the second variant with the Gnome-Rhone 14 like this.
 

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Hi,
In June 1936, another version of the E.48 project was created. It was to be powered by two 850 hp Hispano Suiza Praga 12 Ydrs engines. The weight was much higher than the previous version of this project. The wingspan was 18.1 m, length 14 m. No other technical data has been preserved.

Source: Bittner Collection of the NTM Prague
Praga E-48-II.png
 
Hi,
final version of the Praga E.48 project from July 1936. In this version, the project corresponded to Category IV (multi-seat day and night bomber) of the Ministry of National Defence (MNO), announced in January 1936. The aircraft was of mixed design. The outer parts of the wings and tail surfaces were wooden. The middle part of the wings, the engine nacelles and the fuselage nacelle were welded from steel tubes and covered with duralumin sheet.
The observer was seated behind the pilot in the swivel gun turret and had a 7.7 mm machine gun for defence. The gunner was positioned at the rear of the fuselage nacelle and operated the 12.7 mm machine gun. The lower part of the hull nacelle contained a bomb bay for 1000 kg of bombs. A further 200 kg of bombs could be suspended under the wings. Propulsion was provided by Hispano-Suiza 12 Y 21 engines (manufactured under license by Praga) with 925 hp at an altitude of 3600 m.
In addition to the bomber version, a reconnaissance version was also designed. Some weight and performance data are also available.

Wing span 19,0 m
Length 13,4 m
Height 3,95 m,
Empty 3650 kg
Maximum take-off weight 5772 kg
Max airspeed 440 km/h
Cruising speed 395 km/h
Operational range 790 km

Source: photos are from the book Czechoslovak Prototypes Vol.2, Jakab Jakab Publishing, drawing from the Bittner Collection of the NTM Prague
Praga E-48-III.png Praga E.48-III.png Praga E.48-III_.png
 
Hi,
In June 1936, another version of the E.48 project was created. It was to be powered by two 850 hp Hispano Suiza Praga 12 Ydrs engines. The weight was much higher than the previous version of this project. The wingspan was 18.1 m, length 14 m. No other technical data has been preserved.

Source: Bittner Collection of the NTM Prague
View attachment 694995
Tail feathers loook needlessly complex, but they do improve the arc-of-fire for the top turret gunner.
Also consider that the wing planform hints at the Schumann planform that is now popular with competitive sailplanes and Reno racers.
 
Hi,
the Praga E.48-III project was further developed. The first drawing dates from December 1936 and shows an unspecified version. The second drawing is from January 1937 and shows a reconnaissance version of this aircraft.

Source: Bittner Collection of the NTM Prague
Praga E-48-III_0.png
Praga E-48-III_1.png
 
Very nice my dear Sarastro,

and if you can get these projects; E-200,E-118,E-119,LDP08,LD80 & LD81.
 
Hi,
the study of the Praga E.50 two-seat fighter and combat aircraft, dated August 1936, was a direct response of ČKD-Praga to the specification of the Ministry of National Defence (MNO). Category II of this specification, issued by the MNO in January 1936 under the number (23-308 dův. III/3.36.), was to be a two-seat fighter and combat aircraft. The aircraft was of mixed construction, the wingtips, elevator and rudder were wooden. The fuselage and centroplane had a truss structure welded from Cr-Mo tubes, the covering was all-metal. The powerplant was a Hispano-Suiza 12-Y-25 engine (manufactured by Praga under license) with 910 hp.
Armament: 1 20 mm cannon, 4 fixed synchronized 7.92 mm machine guns and one mobile machine gun, also 7.92 mm, mounted in the rear of the observer's cabin. Bombs weighing up to 400 kg could be hung under the fuselage and wings.
Wingspan 14 m, length 11.2 m, max. speed 455 km/h.

Source: Bittner Collection of the NTM Prague
Praga E-50.png
 
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Hi,
a 1935 study of the Praga E-42 two-seat trainer. It was an evolution of the Praga BH-36. The aircraft was to be powered by a 420 hp Walter Pollux engine. Wingspan: 11.4 m, length 8.9 m. Maximum speed 245 km/m, service ceiling 6 000 m.

Source: Bittner Collection of the NTM Prague

Praga E-42.png
 

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