With the beginning of the war the OKB-28 received a new task of creating a landing glider capable of transporting 11 people. The order to begin development of the glider was announced by the NKAP leadership on July 7, 1941. That day, the deputy commissioner for the experimental construction of the NKAP, AS Yakovlev asked Gribovski how long it would take to project the glider. Gribovski, without much thought, replied that two months. Considering the response little serious, Yakovlev asked him to put this commitment in writing and signed.
The first plans for the construction of the G-29 (Russian: Грибовский Г-29) were delivered to the production workshops on July 11 and by August 2 the glider was practically finished. On September 1, with a few days remaining for the two months, the new model, named by the OKB G-29 (Gr-29), was ready for the first flight.
The G-28, also known as the Gr-29, was designed as a landing glider with a monoplane structure with a high cantilever wing and entirely made of wood.
The wing had a box-shaped double spar structure, made of wood. The wing profile used was the R-II. The centroplane had a rectangular shape and the wing consoles were fixed to it with inflection on the leading edge and the straight trailing edge. Wing mechanization included ailerons and flaps, located in the wing soffit and intended to improve landing characteristics. In the upper and lower part of the fuselage there were emergency hatches measuring 0.51×0.46 meters, which could also be used for the defense of the glider.
The fuselage was box-shaped with a rectangular cross section. The entire construction had been conceived paying great attention to the simplicity of production and the necessary structural strength. In the central area of the fuselage, there were two master frames to which the centroplane was attached. The cargo cabin, 3.24 meters long and 1.36-1.25 meters wide, featured 1.2 x 0.7 m cargo doors on both sides, as well as two small rectangular windows, which could be opened for operation. shot from them. Wooden benches were placed on both sides of the walls to accommodate the landing troops.
The tail was of the conventional monoplane type with large surface rudders.
The landing gear was a fixed combination type, with 600 x 250mm wheels used during takeoff and a ski on the underside of the fuselage for landings. A crank on the left side of the cockpit allowed the main landers to be retracted for landing. The use of skis significantly decreased the landing roll.
In the nose area there was a single-seater cockpit for the pilot with the steering organs and covered by a transparent lantern that opened up and back, pivoting on a hinge. The cabin equipment was quite austere (a clock, a speedometer, a barometer, an angle indicator and an altimeter).
The first test flight was on 1 of September of 1941 performed by VL Rastorguyev. The good results obtained resulted in the approval of the serial construction of the model in two factories on September 18: number 471 in Shumerlya city and 494 in Kozlovka village.
At the end of September, the military acceptance tests were carried out, which showed totally acceptable results. As a conclusion, a request was made to slightly advance the wings to achieve the necessary centering of the plane once it had been abandoned by the paratroopers.
The tests also showed that with the glider empty and the flaps extended, the tail creaked. This was eliminated by introducing perforations in the flaps.
The 28 as September as 1941, as soon as they finished the tests, Gribovski traveled to the Factory No.471 and his deputy, Landyshev the Factory No.494. Already on October 18, the first base prototype for production arrived in Shumerlya together with a group of specialists from the OKB-28. By the end of the year, Factory No.471 had finished 10 copies, which soon entered service with the Landing Troops (VDV), receiving the name G-11 (in view of the number of places).
The production of the G-11 was maintained until June 1942, when it was concluded that the military was not prepared for the execution of large landing operations with gliders. The lack of prepared crews in tow and glider pilots was being felt. The absence of conditions for the conservation of these airplanes caused them to be affected by weather conditions, which affected their resistance and reliability.
As a result of this situation the production of the G-11 glider was stopped in 1942 . The OKB-28 collective was reassigned as technical personnel to Factory No.471, which at that time received the mission to start producing the Yakovlev Yak-6. Gribovski was placed at the disposal of the Commissariat for the Aeronautical Industry (NKAP).
In the year of closure of production, Factory No.471 had produced 127 copies (to which must be added the 10 produced in 1941 and the prototype), while Factory 494 delivered 170 copies. Thus, the total number of units produced in this first stage reached 308 copies.
At the end of 1943, the logistical supply needs for guerrilla and combat groups caused the restart of production. This time the Ryazan aviation factory was chosen as the production base. Vladislav Gribovski would be appointed chief builder.
The first G-11 produced in Ryazan was tested in March 1944 by the glider test pilot Lieutenant Chubukov, who even performed spins, inverted flight and barrel roll.
During production various modifications were made. Starting from the standard number 21 on the left side, an increased door 1.4 meters wide with two-leaf opening was introduced. The cargo door located on the right side, present in previous versions, was eliminated. The number of copies produced at this stage, which would last until 1948, is unknown. It is estimated that the total number produced was between 500 and 600 copies.
By the final stage of the war, the VVS leadership had internalized the importance of the gliders in the actions of rapid troop transfer, carrying out surprise attacks on enemy positions, supporting offensive missions and supplying logistics to units. The experiences during the war had not been good, so it was necessary at high speed to start working on the preparation of glider crews and the development of preparation exercises in this type of operations.
As of October 1944, the manufacture of landing gliders equipped with dual flight control, a landing ski suspension system and structural reinforcements would begin in Ryazan. This version would be renamed G-11U.
Production of the G-11U version was closed in mid- 1945, but a little less than a year later it would be resumed, remaining until 1948.
In 1942 Gribovski proposed to develop on the basis of the G-11 a motor glider with an M-11 engine, which would eventually be produced in prototype form under the company name G-30, although it was also known as G-11M.
The landing actions carried out in the USSR during the war were scarce and in some cases catastrophic. The main use of gliders was restricted to specific supply operations, fundamentally to guerrilla groups and the transport of small sabotage units, which operated in the enemy rear.
Perhaps the most brilliant performance of the landing gliders took place in 1943 when they were used in supplying the Belarusian guerrillas in the Minsk region. The gliders were prepared to transport fuel, weapons and ammunition, including those for cannons.
The glider launch operation over Belarus was kept a great secret, so for the Germans it was totally unexpected. This operation was directed by the headquarters of the Air Landing Troops (VBV) and its development was personally followed by Stalin.
It was planned to be executed at night. Ilyushin DB-3F and Lisunov Li-2 towed Moscaliov and Gribovski gliders in pairs, releasing about 50 to 60 km from the target. The guerrillas had prepared surfaces for the landing and at the agreed time they lit bonfires as signalling. This operation was successful and allowed the Belarusian partisans to achieve significant successes against the fascist groups.
The aeronautical designers OK Antonov, AS Moscaliov and VK Gribovski received the 2nd rank “Guerrilla of the Great Patriotic War” medal for their contributions to the partisans, which was one of the few exceptions for the delivery of this medal to personnel from the deep rear.
The G-11 gliders were also used on a small scale during the crossing of the Dnieper, carrying guns and mortars from one shore to the other. Another notable action was the creation of a supply bridge between Moscow and Stalingrad in November 1942 to carry deicing fluids for Soviet tanks, which were preparing for the offensive.
Versions:
G-29 (G-11)
Original version as a transport glider from 1941 with capacity for 11 people and a rectangular section fuselage. Built 308 copies in factories 471 in Shumerlya city and 494 in Kozlovka village.
G-11U
1944 training version with dual controls, structural reinforcements and changes to the landing gear. The quantity produced is unknown.
G-30 (G-11M)
Motorized version of the G-29 with M-11 powerplant. A prototype was built in 1942. With the closure of production in 1942 the development would be abandoned.
Specifications
G-11
Wingspan: 18.00 m
Wing area: 30.00 m²
Length: 9.71m
Height: 2.7 m
Empty weight: 1250 kg
Maximum takeoff weight: 2400 kg
Wing loading: 83 kg / m²
Payload: 10 equipped soldiers or 1200 kg
Surface of the horizontal planes: 5.64 m²
Vertical plane surface: 2.7 m²
Spoiler area: 3.1 m²
Maximum towed speed: 370 km / h
Maximum planing speed: 146 km / h
Glide ratio: 16
Accommodation: 1
All Aero 