Bratuchin G-4

Bratukhin B-4
Братухин Г-4
     
Název:
Name:
Bratuchin G-4 Bratukhin G-4
Originální název:
Original Name:
Братухин Г-4
Kategorie:
Category:
průzkumný/pozorovací vrtulník reconnaissance/observation helicopter
Výrobce:
Producer:
DD.MM.1946-DD.MM.1948 Kyjevský letecký závod č. 473, Kyjev /
Období výroby:
Production Period:
DD.MM.1946-DD.MM.1948
Vyrobeno kusů:
Number of Produced:
2 prototypy + 4 sériové stroje
První vzlet:
Maiden Flight:
DD.MM.1946 podzim / autumn
Osádka:
Crew:
2
Základní charakteristika:
Basic Characteristics:
 
Uspořádání rotorů:
Rotor Configuration:
rotory vedle sebe twin side by side rotors
Podvozek:
Undercarriage:
pevný fixed
Přistávací zařízení:
Landing Gear:
kola wheels
Technické údaje:
Technical Data:
 
Hmotnost prázdného vrtulníku:
Empty Weight:
2634 kg 5807 lb
Vzletová hmotnost:
Take-off Weight:
? kg ? lb
Maximální vzletová hmotnost:
Maximum Take-off Weight:
3002 kg 6618 lb
Délka s otáčejícími se rotory:
Length with Rotors Turning:
? m ?
Délka trupu:
Fuselage Length:
8,60 m 28 ft 2 ⅝ in
Šířka trupu:
Fuselage Width:
? m ?
Celková výška:
Overall Height:
? m ?
Průměr hlavního rotoru:
Main Rotor Diameter:
7,70 m 25 ft 3 ⅛ in
Průměr vyrovnávacího rotoru:
Tail Rotor Diameter:
- m -
Plocha disku hlavního rotoru:
Main Rotor Disc Area:
93,13 m2 1002.44 ft2
Plocha disku vyrovnávacího rotoru:
Tail Rotor Disc Area:
- m2 - ft2
Pohon:
Propulsion:
 
Kategorie:
Category:
pístový piston
Počet motorů:
Number of engines:
2
Typ:
Type:
Ivčenko AI-26GR o výkonu 368 kW/500 k Ivchenko AI-26GR, power 493 hp
Objem palivových nádrží:
Fuel Tank Capacity:
? ?
Výkony:
Performance:
 
Maximální rychlost:
Maximum Speed:
148 km/h v ? m 92 mph in ? ft
Cestovní rychlost:
Cruise Speed:
96 km/h v ? m 60 mph in ? ft
Rychlost stoupání:
Climb Rate:
? m/s ? ft/min
Statický dostup:
Static Ceiling:
? m ? ft
Dynamický dostup:
Dynamic Ceiling:
2400 m 7874 ft
Dolet:
Range:
233 km 144.8 mi
Maximální dolet:
Maximum Range:
? km ? mi
Přepravní kapacita:
Transport Capacity:
? ?
Výzbroj a vybavení:
Armament and Equipment:
 
Výzbroj:
Armament:
- -
Vybavení:
Equipment:
- -
Uživatelské státy:
User States:
- -
Poznámka:
Note:
J. Fojtík v knize Ruské vrtulníky uvádí vyrobený počet 2 prototypy + 5 sériových strojů + dalších 25 kusů J. Fojtik mention at book Russian helicopters different data - 2 prototypes + 5 series machines + 25 another examples
Zdroje:
Sources:
http://www.airwar.ru/enc/uh/g4.html
http://cs.wikipedia.org/wiki/Bratuchin_G-4
www.aviastar.org
Fojtík, Jakub, Ruské vrtulníky, Svět křídel, Cheb 2009
URL : https://www.valka.cz/Bratuchin-G-4-t57870#518228 Version : 0
Bratuchin G-4 (Г-4)

OKB-3. P. Bratuchina (ОКБ – 3 И. П. Братухина), the first specialized soviet design bureau on the development of helicopters, was in February 1946 decree of the government entrusted with the development of two new helicopters with the engines On. G. Ivčenka (О. Г. Ивченко), namely a three-digit helicopter for the management of artillery fire, known as the G-4 and the six-digit civil transport helicopter, known as B-4. While the cabin of the machine G-4 should provide a space for one pilot, one observer and one passenger inside the cabin of the transport type B-4 (later, due to the amount of design changes přeznačeného as B-5) should be a seat for one, respectively two pilots and five, or four passengers.

The first point of the government's award of the demanded to the machine for guidance of artillery reached a maximum speed of at least 230 km/h in the amount of 3000 m, had a static availab no less 4000 m, and the dynamic to 6000 m and the time duration of the flight for three hours. Enter the required pass of the machine to the customer on the state tests to 1. June of the same year. Really hard conditions. Maybe also because of the OKB-3 did not develop a completely new design, but only rephrase the previous type of the Omega (Братухин Омега), which took over virtually unchanged the hull and part of the structure of the beams of the propulsion assembly. Engine Ivchenko M-26GR (М-26ГР), in the amount of 2000 m, the rated power of 460 PC, and, after raising his performance to 550 PCS (using the change of supercharging), was formed variant of the M-26 GR(F) - М-26 ГР(Ф), who received later the designation AI-26 GR(F) - АИ-26 ГР(Ф). This variant became the first soviet vrtulníkovým engine, extensively used on the Me-1 (Мил Ми-1). Engine M-26GRF in last modification - when empty weight 445 kg - amounted to take-off power 575 pcs., and the rated power - 460 KS in the amount of 2000 m.

Machine with ce G.- 4 is lifted into the air only in the autumn of 1946. however, in July the government ordered kyjevskému race no 473 to produce on 1 February 1947 the first five machines. A later regulation was established to produce an additional 25 helicopters. The main head of stage racing tests the machine were an engineer G. In. Remezov (Г. В. Ремезов) and pilot M. To. Bajkalov (М.К.Байкалов), previously head of production G - 3. After he flew only 16 hours and 18 min., he was 28. January 1948, during the test, the glider landing in a mode of autorotation, this machine piloted by M. To. Bajkalovem due to an error of the test pilot, for which in part could also be the lack of vycvičenost, he began to getting faster fall from a height of 50-60 m, after which from approximately 10 m, passed into a disorderly fall and hard hit on the ground. The cause of the accident, in the opinion of the commission, consisted in the mis-implementation stabilisation of the machine before landing. The Pilot of the accident took only a fright, but the machine, due to the significant damage has already been repaired, It must be said that for Bajkalova, showing a total raid on the aircraft more than 2000 hours, it wasn't his first accident on the helicopter. His first crash occurred in June 1947 on the helicopter G - 3, then, but the cause has not been established, and the helicopter had to be thoroughly repaired.

The second prototype helicopter G - 4 Double (Дублёр) into the test program involved in the April 1947. While the leaves of the main rotors of the prototype of the first were equal, in the prototype second should zkrut at an angle of 6° 45‘.which favorably affected its flight characteristics. Part of racing tests the second prototype of the helicopter type G-4 shall have become, as in the case of the prototype of the first, also tests aimed at checking the abilities and level flight with one working engine.

Helicopter type G-4 was, therefore, in the case of failure of one propulsion unit capable of continuing the flight at constant flight level. If the reported activity of both engines, managed to land gliding flight in a mode of autorotation. In the context of racing tests the second prototype of this machine in the course of just two months, made a total of 44 test flights with a total duration of 7 hours and 52 min.

Part of racing tests the second prototype helicopter G-4 while have become also 100 hours of continuing ground fatigue tests of transmission and the individual components of the carrier system. Those tests were implemented in the summer of 1947 on the soil test institute NII VVS and in their course have been able to detect that the installation of new engines and new rotors with a larger diameter the level of vibration of the airframe against the model G-3 not changed.

The same month, but was yet another accident. This time the damage to the test G - 4 occurred through the fault of the pilot, due to too harsh a landing. A number of accidents on the helicopters ended Bajkalovova death to the experimental Mi-1, where when passing the machine to the customer before landing damaged the balancing of the propeller.

The pilot Ponomarevovi and engineers Macickému (Мацицкий) on the second prototype managed to meet a number of tests. Specifically, for the first time in domestic practice, landing in the mode of autorotation. While the speed of the sliding, reaching 160 km/h, and the vertical rate of descent of 12 m/s Coasting after landing at a speed of 80-90 km/h amounted to 15 m. In the context of racing tests the second prototype of this machine in the course of just two months, made a total of 44 test flights with a total duration of 7 hours and 52 min.

Mass production of machines, launched in June 1947 also it was not all right. The first serial G - 4 (a total of were produced 4 pieces) was eventually to racing tests passed at the end of march in the year 1948, therefore, with considerable delay against the original plans. As mentioned earlier is provided In. G. Marejev (В. Г. Мареев). The same month, but they occurred at once two accidents. Their cause yet consisted mainly in the lack of experience of the test pilots with piloting helicopters. In August 1947 on the traditional air show, which was held in Tušinu helicopter G-4 snubbed his public debut. At the mentioned show it was possible to see in formation with a pair of helicopters of the type G-3. At the end of the summer of 1947, after graduating from the 100-hour stress test, advanced exam GK NII VVS. The main persons tests were engineer L. N. Marin (Л. Н. Марьин) and pilot G. And. Tinjakov (Г. А. Тиняков). Among other things, also checked the vibration, which, in the early years of the experienced pilots. The correction should bring the replacement of the propulsion system. However, the new power unit and carrying a propeller of larger diameter has not shown the level of vibration no effect. Insurmountable problems with the vibration of the airframe was complicated by flight tests of this machine continue. But this time of the oscillation discussed not only pilots, but also oscilogramy, recorded using sensors placed on various locations of the helicopter. The second prototype of the helicopter type G-4 in the state trials, which unfolded in may of 1948, he failed and in August of the same year was returned to the OKB-3.
Therefore the serial production of the helicopter type G-4 finally stopped on only four specimens. From the production of the next series of 25 pieces naturally gathered together also.


Sources:
ruslet.webnode.cz
http://www.airwar.ru/enc/uh/g4.html
http://cs.wikipedia.org/wiki/Bratuchin_G-4
www.aviastar.org
Also, Jakub, Russian helicopters, the World of wings, Cheb 2009.
URL : https://www.valka.cz/Bratuchin-G-4-t57870#518223 Version : 0
The machine was equipped with the standard camouflage and red stars, even though it anticipated user - VVS USSR - never taken..
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Bratuchin G-4 - Nástup do stroje po žebříku při visení.
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Nástup do stroje po žebříku při visení.
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