Designed by Emilio Bianchi and built in 1953 by the Gruppo Costruzioni Aeronautiche, the GCA.1 Pedro is a side-ny-side two-seat cabin monoplane powered by a 60 hp C.N.A. D4 air-cooled engine.
The Pedro is of all-wood construction with plywood covering. Dual controls are fitted.
Engine: 60 hp C.N.A. D4 Wing span: 32 ft 1.5 in Wing area: 140 sq.ft Height: 6 ft 2.5 in Empty weight: 748 lb Loaded weight: 1276 lb Max speed: 106 mph Cruise: 93 mph Time to 3280 ft: 6 min 30 sec Service ceiling: 14,100 ft Absolute ceiling: 17,550 ft Cruise range: 342 mi
The Gruppo Costruzioni Aeronautiche was a group of aircraft enthusiasts who built aircraft of their own design at the Instituto Industriale in Pisa, Italy.
USSR Two-seat commercial biplane designed by E. E. Groppius and built in late 1924 by a State factory in Moscow. Powered by 300 hp Hispano-Suiza engine.
The second design of French military officer Alfred Groos. Produced in 1909, a small monoplane which was named “Quand même” [“Nevertheless”].
It was tested on 30 July 1909 as it flew about 100 meter with a speed of 55 km/hr at a height of ca. 2 meter. When it came down one part of the wing was damaged and the propeller broken. The monoplane had a four-wheel undercarriage (2 bigger in front and 2 small ones behind) and a very simple “fuselage” – about one piece of wood – and was powered by a 25 hp Anzani.
French military officer Alfred Groos first produced in 1909 an unsuccessful little triplane. Also in 1909 he produced an equally small monoplane which was named “Quand même” [“Nevertheless”].
A third machine was designed by Groos, a further development along the lines of the “Quand Même”. It wasn’t named after Groos, but was known as the Paul Kaufmann monoplane of 1909.
Built in the UK, this 1903 machine, which was about 80 feet in length and 60 feet in width, was to be supported on superposed planes attached to the framework both at the front and rear of the machine. It had three propellers on each side of the framework, and an extra one surmounting the whole structure. The propellers were carried on arms extending from the central driving shaft which form an axis within a rectangle, the two vertical sides of which form axes carrying the vanes of the propellers. During the driving stroke the vanes extended outside beyond the rectangle, while they returned edgewise, in a feathering position, inside it.
Starting in 1931, Grokhovsky worked on systems for air landing. One of the systems, the Grokhovsky G-61 (Russian: Гроховский Г-61), was to take advantage of all the payload capacity of the aircraft models without affecting their structure. It allowed a stock Polikarpov R-5 reconnaissance biplane to lift 16 people.
Grokhovsky decided to save resources in construction of specialized aircraft by installing two specially designed cassettes under the underwing of a stock R-5. Each had several compartments designed to carry one soldier.
The first model of the G-61 container had capacity for two paratroopers and could be opened downwards to allow jumping.
To reduce aerodynamic resistance, the cassettes were designed as a thick wing profile and by protruding from the wing plane in the front and rear area, they increased the wing area by about 7 sq.m. According to the opinion of the institute’s specialists, this should constitute an increase in the lift force and therefore increase the payload capacity of the model. The new leading edge was formed by transparent curved surfaces of Plexiglas, covering the entire width of the cassette and reinforced with a plywood structure.
In addition to transporting soldiers, these cassettes could be used to evacuate the wounded, transport supplies and cargo. Outside the military sphere, the cassettes were used to transport expeditions to remote places, carry out rescue missions, among others.
Cassettes with different capacities were designed, depending on the mission. One of the first versions of the G-61 had only 4 compartments, each calculated to transport a person weighing about 80 kg. The bottom of the compartments could be opened in flight. In this way the pilot could release loads with a parachute or launch the paratroopers into the air.
By 1935 this G-61 system passed factory tests and was delivered to state tests, but Grokhovsky kept working on higher capacity versions.
In 1936 a new version was designed. Each cassette held 7 soldiers, bringing the R-5 ‘s capacity to 15 soldiers (including one in the aircraft’s second seat). The construction turned out to be quite light, only about 200 kg. The entire structure of the R-5 was reinforced.
Yakov Alksnis and NN Polikarpov openly expressed their skepticism about the success of the new version. However, by that time Grojovski had a well-earned reputation, so he was given permission to fly his creation. The most difficult thing was finding a test pilot who wanted to test it. Three would refuse, so Grojovski finally decided to take the risk.
On December 8, 1936 at the NKTP Central Airfield in Podlipki an R-5 plane took off with the two new cassettes. The flight had been planned with sandbags until the expected takeoff weight was achieved. These sacks were jokingly known as “Iván Peskov” because this surname means “Son of the Sand”. When Alksnis and Polikarpov arrived to supervise the flight, the plane had already been loaded and the cassettes closed.
The plane with its ski undercarriage traveled around the runway for about 350 meters and took off. At the controls was Pavel Grojovski. The plane made a low-altitude circle flight and took to the runway. The surprise was tremendous when the cassettes were opened and it was found that instead of bags there were 14 Grojovski collaborators. The “official” explanation was that the Iván Peshkov sacks had not arrived on time for the tests and the collaborators had volunteered to take on the weight. In reality, this fact constitutes a sign of the confidence that the workers of the institute had in their boss.
Grokhovsky poses with his teammates after the successful test.
The take-off weight on this flight, including the pilot, a passenger and an auxiliary 250-liter fuel tank, reached 1,650 kg (tests were carried out with weights up to 2,000 kg). Top speed was set at 180 km/h and cruising at about 160 km/h.
The R-5 plane with the G-61 containers under the wings after Grokhovsky ‘s flight with 14 of his companions.
Despite Grokhovsky ‘s successes at that time, he began to move away from issues related to the landing to concentrate on aeronautical production. In 1937 the institute would be reorganized and all these works abandoned.
The Polikarpov R-5 with the 14 paratroopers under the wings during tests in December 1936.
On 12 August 1937, during an attempted flight to the United States via the North Pole, the crew of the Bolkhovitinov DB-A (“Н-209”) would go missing with the crew led by polar pilot SA Levanevski.
On August 25, 1937 Grokhovsky wrote a letter to Stalin in which he reaffirmed that the capacity of the R-5 with the G-61 could be raised from 1,650 to 2000 kg. This would make it possible to locate auxiliary fuel tanks with a pump transfer system to the main tanks and increase the range of the P-5 (civilian version of the R-5) to 3,000 km. In 7 – 10 days Grokhovsky promised to have the cassettes ready. In addition to fuel, these capacities could take food for several months, a tent, an inflatable boat, and all the necessary instruments for a prolonged search.
Grokhovsky further enunciated the advantages of the R-5 for the task due to its ability to land and take off on relatively short runways, the presence of dual flight control, and the possibility of transporting the entire return crew in a single aircraft. The letter ended with a request to allow to equip a P-5 with cassettes and allow it to participate in the search for the crew of “Н-209”.
Grojovski ‘s request was approved. Two P-5 airliners were loaned from the GVF’s northern direction. The first, with factory number 8458, had been delivered in 1934, receiving registration СССР-Л1565 in August. The second example, with factory number 9627, would enter service in June 1935 with registration СССР-Л1937. Both examples received the designation PG-61.
The cassettes were installed in Factories No.89 and 241. The engineers Gubanov (Factory No.241), Mladkovski (GVF Main Directorate), Vorozhtsov (NII GVF) and instrumentalist Lomtiev played a vital role in the modifications.
PG-61 with wing cassettes. The radio station antenna is clearly visible on the rear fuselage.
The modifications made made it possible to increase the takeoff weight of the P-5 to 4050 kg. The cassettes were designed in such a way that all the weight was concentrated near the center of gravity of the model.
On September 12, 1937, the aircraft, registered СССР-Л1565, took off from Moscow to Arkhangelsk with the pilot of the experimental institute Boris Bitski. In two days it reached its destination, where the plane was disassembled for transport aboard the steamer “Roshal”, which was traveling to Rudolf Island in the Franz Josef Land archipelago .
PG-61 СССР-Л1937 takes off towards Arkhangelsk.
The second example СССР-Л1937 was kept in Moscow for a set of tests. Auxiliary fuel tanks with a total capacity of 840 liters were installed in six of the 8 cassette compartments. The takeoff weight with fuel rose to 3350 kg. In the rest of the compartments there was a reserve radio station, food for two months, weapons, sleeping bags, and additional parts for minor repairs to the plane. The takeoff weight grew to 3780 kg. Instruments for blind flights, a radio-compass and powerful radio equipment were installed in the piloting cabins.
Fuel tanks located on the G-61 cassettes.
On September 16, 1937, pilot IS Kotov and the radio operator Degtiev began the tests of the aircraft at the Bykovsky airfield. Only four flights were carried out in which it was possible to determine that the aircraft behaved quite well in flight and could be controlled without difficulty, despite its great weight. Takeoffs and landings and horizontal flight of maximum and minimum speeds were tested. The plane behaved well and not unlike the normal P-5.
During the takeoff run, no tendency to deviate to one side was recorded. Takeoff occurred at a speed of 90-95 km/h and the run lasted about 18 seconds.
Horizontal flight was tested at speeds between 135 and 185 km/h. Gliding was tested at speeds of 135 – 140 km/h, demonstrating good stability.
The landing was not unlike normal P-5 aircraft. The auxiliary tank system also passed the tests.
After the culmination of the tests, the СССР-Л1937 plane flew to Moscow, from where it departed for Arkhangelsk, taking on board the same crew that participated in the tests. In Arkhangelsk the plane was disarmed and its crew joined that of the other plane, which had not yet boarded.
The Roshal steamer arrived in Arkhangelsk on October 1. The loading of the ship took 5 days. At the end of October, it would arrive at the island of Rudolf, where a group of Tupolev G-2 planes (civilian transport version of the Tupolev TB-3 bomber) were already present. Despite the number of aircraft and crews, constant weather problems did not allow the pilots of these aircraft to conduct an active search for Levanevski’s aircraft.
Unlike these large aircraft, which arrived flying under their own power, the P-5s, after unloading, had to be fuelled and transferred to the improvised runway. During final preparation on December 2, the ice under Bitski’s aircraft gave way and the СССР-Л1565 aircraft plunged about a meter, damaging its propeller. Next to the plane, Chuxnovski, who was helping in the preparation, fell into the water.
On December 8 both planes were prepared for flights. Both pilots calculated that the weather would improve and in about four days they could take off. In one of the planes the navigator LM Rubinshtein would travel. Inclement weather thwarted this plan.
The weather situation improved only on the 20th and the P-5s, together with Chuxnovski’s G-2, were ready. Bitski and Kotov tried twice to take off, but a broken tail skid prevented them from taking off. It is unknown if the PG-61 took part in the rescue flights or not.
It is known that СССР-Л1937 survived this adventure and was still flying at the beginning of 1941. The fate of the P-5 СССР-1565 is unknown.
Grokhovsky G-61 Powerplant: One M-17B, 680 hp takeoff / 500 hp rated power Wingspan:15.5/12.6 m Wing area: 50.2 m² Length:10.56m Loaded weight: 3800kg Wing loading: :75.7 kg/sq.m Power load: 7.6 kg/hp Payload capacity: 15 soldiers Cargo volume :4.3 cu.m Top speed: 201km/h Cruising speed: 130 km/h Take-off run max load: 400 m (30 sec) Ceiling: 2800m Accommodation: 1-2
In 1934 Grojovski began experiments installing conventional weapons used by ground units on bombers. Initially as part of the experiments, he fitted a Tupolev TB-3 bomber with a 76mm regimental gun. The gun was installed under the fuselage, in a structure 600 mm from the bottom of the fuselage. The tests were carried out between December 15 and 18, 1934, first with shots from the ground and then during the flight. As a result of these tests, it was declared that firing with 76mm regimental guns from aircraft is possible.
After these results Grojovski began the development of a version with more powerful weapons, again on a TB-3 bomber. This version was called “Letayuchaya Baterieya” or “Flying Drums” and received the designation G-52 (Russian: Гроховский Г-52 “Летающая Батарея”) in the institute’s consecutive year.
The G-52 “Letayuchaya Baterieya” heavy attack aircraft was submitted for state tests in December 1935. It was a Tupolev TB-3 bomber with M-17 engines and armed with cannons.
After reviewing several installation variants, it was agreed to install a 76 mm anti-aircraft gun (1931 model in the nose.). The developers were forced to shorten the nose, which forced the elimination of the navigator’s position in the bow. The long tube of the gun was located between the pilots’ stations, protruding by about 250 mm at the bow of the aircraft. The body of the cannon was fixed to the upper and lower partitions of the spars of the center plane, by means of a system of adjustable rods. From the nose and up to the pilots’ position, the barrel was covered with a tube to prevent the entry of gunpowder gases into the cockpit. The reloading of this cannon for firing was done manually. To achieve this, the gun server position was located in the fuselage, with a small seat and some shelves for the projectiles.
In the wing consoles two 76 mm field guns (1927 model). To install the guns on the TB-3 bomber , the gun carriage with the wheels was eliminated, maintaining the recoil compensation system. The server for each gun sat during the flight on a mattress attached to the wing structure.
Grojovski G-52 during state tests
The main task for which the G-52 was conceived was fire support to landing troops. The range of the artillery salvoes was 18 km and the location of the target was done during the turn. To achieve some aim, a standard collimator was located in front of the ship’s commander’s post. Each shell had a weight of 6.5 kg.
According to the assertions of its builders, the three cannons of the “Letayuchaya Baterieya” could fire up to 27 shots per minute. This really does not seem credible due to the lack of automatic recharging systems at the time.
The order to fire was obtained by means of light indicators. The ship’s commander had a control board with switches and indicator lamps.
When the commander connected the switch, the piece received the instruction to prepare to fire. When loading the projectile, the server of the piece pressed his switch to indicate that he was ready. After taking the plane to the target, the commander pressed a button and a red light illuminated in the room, indicating the order to fire. In case of need, the wing guns could be fired using a remote control system. For this purpose, cables were located from the cockpit to the wing locations.
The navigator, originally located in the bow of the bomber, in this version came to occupy a position on the left side of the rear part of the fuselage, just above the wing trailing edge area.
This system in general must have turned out to be not very functional, first of all due to the need to approach the target without an aid system for the pilots, maintaining the course during the entire approach despite the interference caused by the enemy fighters and the anti-aircraft systems. On the other hand, the lack of aiming systems guaranteed a very low level of success. During the tests it was also found that the smoke from the cannon shot leaves the pilots practically without visibility.
Grojovski’s experiments in this direction were simply abandoned.
Practical work on the development of a “tailless” aircraft began at the Oskonbyuró (Bureau for Special Constructions of the VVS RKKA) in Moscow at the beginning of 1933. The group led by Grojovski had previously tried to venture into this type of apparatus, but the large number of “gaps” did not allow it to seriously engage in the development of such a complex task. In particular, the issues related to the achievement of the necessary stability in flight became more complex.
Grojovski also clearly understood the need to start with experimental models. Only phased development would allow the necessary experience to be obtained, but this principle was foreign to the bureau’s way of working. Since its creation, all the works conceived by the group under the direction of Grojovski had a practical nature, designed so that once the tests were completed, they could go directly into service.
In those years attention began to be paid to a new type of aerial combat: the demolition of the enemy plane by ramming. In Russia this method was popularized by the pilot Nesterov and received the name “Taran”. Generally the “Tarán” was carried out placing the own plane at 6 o’clock from the enemy and cutting its tail planes or wing tips with the propeller. In the best of cases, the attacking aircraft landed with a damaged propeller, in many others it ended up destroyed along with its opponent. The “Taran” method was promoted during the first stage of the Great Patriotic War, when German aviation had air superiority. Many Soviet pilots rammed their planes into the enemy in those unequal combats.
Grojovski decided to study the possibility of building a plane specialized in ramming. It was a matter of designing a model capable of inflicting great damage on the enemy plane without great damage to its own. The result of this work was an aircraft without analogues for the time that received the name G-39 from the institute and the nickname “Cockroach” (Russian: Гроховский Г-39 “Кукарача”).
As a basis for Grojovski ‘s thought, an example without tail planes was designed. Along the entire leading edge of the wing, a “knife” was installed, a thin, sharp sheet of high-strength steel. In the bow, the installation of a long bar with sharp edges was foreseen, which was to protect a pneumatic cannon. Between this bar and the wing consoles a fine steel cable was installed. It was thought that at the moment of impact, either with the cable or with the edge of the leading edge, the enemy’s tail would be destroyed.
In general, the G-39 repeated Cheranovski ‘s flying wing schemes. The short, cigar-shaped fuselage featured an enclosed bubble-like cockpit forward. In front of the windshield was an armored plate.
The wing had a 38º leading edge camber and ended in vertical surfaces inserted into the trailing edge. The tips of the wings inclined downwards.
At the rear of the fuselage, within a semicircular indentation in the wing, the propeller was located in a drive configuration. The engine was installed at the rear of the fuselage using a special system that allowed it to rotate the engine from its horizontal to vertical position. In this way, the variable pitch propeller was converted from a driver to a tractor and generated the necessary lift to allow vertical takeoff.
The landing gear of the G-39 featured four wheels. The main units featured long landing gear covered by a thin fairing and attached to the wing root, at the point of junction with the fuselage. The other two wheels were located in the lower part of the wingtip vertical surfaces.
From the drawing stage of the new model and by virtue of its appearance, the designers named it “Cockroach”.
Among the novelties incorporated in the development of the model was the introduction of vertical takeoff capability. The idea of such a possibility had been presented by Grojovski in his work “Installation of a power unit in the middle zone of the fuselage”. With this decision the technical task was to develop a tailless ramming aircraft capable of vertical takeoff and landing. The general conception of the new plane was patented by Grojovski on February 25, 1935.
Despite its technological novelty, the new model was based on a body of documented discoveries, calculations, patents, and innovations. On the other hand, there was the trust of the group in the intuition of their boss. Even without the necessary technical preparation and unable to explain how and why, Grojovski always ended up being right, even in those cases in which “science” suggested that his ideas were theoretically incorrect. For this reason, the new task did not raise doubts as to its success, neither in the bureau workers, nor in the invited specialists, and soon the new G-39 model began to take shape on the drawing sheets.
The task was presented with its specifications, but the bureau group lacked knowledge and experience for its development. A group of specialists, VF Bolkhovitinov, SG Kozlov and A. Ye Kaminov were contracted for the conception of the project.
The development and construction of the “Cockroach” was carried out in difficult conditions. The invited specialists could dedicate only their free time to the design, mainly at night. The model was not registered in any development plan, so it had no allocation of material resources.
The construction was carried out in the workshops of the TsAGI. Getting a new engine was impossible, so they had to be content with the underpowered 100-hp M-11, removed from another aircraft. To build the fuselage they had to use leftover materials from other productions. The shortage of qualified personnel was constantly felt. The lack of specialized equipment in the TsAGI workshops made it necessary to simplify the project.
The closed cockpit was replaced by an open one with a windshield. The semicircular slit in the wing, in the position of the propeller, was replaced by a rectangular one. As a result of this modification, the triangular wing ended up becoming a swept wing and its trailing edge a large horizontal stabilizer with a large area and span.
The prototype lacked the ramming equipment, neither the wing knives, nor the installation of the nose system with pneumatic cannon could be installed in the conditions of the workshop.
Another feature that seems to disappear in this prototype was the possibility of vertical takeoff. At least no evidence is collected to show that it was ever tried by the participants in the tests.
The TsAGI workshops were commonly visited by Valeri Pavlovich Chkalov. He had been entrusted with the task of testing the plane and for this reason he considered it mandatory to know the apparatus at the assembly stage. Under his advice, the cabin was set up and the equipment and instruments were placed in the correct position.
At the end of the spring of 1935 the “Cockroach” left the workshops for the development of the tests. Seeing him on the track, Chkalov commented:
“Oh! It actually looks like a cockroach. I’ll try it.”
However, flying the “Cockroach” proved impossible. The G-39 ran down the runway increasing its speed but in no case did it get up on the runway. Chkalov, not giving up, raced the plane up and down the runway failing to get it airborne until the fuel ran out.
Irritated and addressing the plane’s designers, he blurted out:
“A real Cockroach and Cockroaches don’t fly! Somewhere you miscalculated or overthought, distinguished!”
The failure of the G-39 can be explained by a series of causes: The low motor power; The position of the propeller in relation to the fuselage, the wing and the fairings of the main landers contributed to diminish the effect of the propeller; The low quality of the construction of the plane;
With all these problems against, the “Cockroach” was unable to take flight.
But Grojovski did not give up his efforts and, not without the help of some important people in the VVS, managed to have the “Cockroach” project included in the official plan of the NKTP Experimental Institute. For this he had to abandon the idea of the vertical takeoff. Work on such a “progressive” model would not have received support.
The contract with the invited specialists was not renewed. Grojovski put his replacement VD Urlapov in charge of development, taking into account that the project already existed and the experience had been accumulated to take on the job. Three months later in the Soviet press would appear: “The experimental institute of the Narkomtyazhprom in Leningrad begins the development of a model of a flying wing with a 100-hp engine. This plane can carry four passengers and fly at a speed of 220 km/h. In a period of two and a half months the plane should be ready to participate in the all-Soviet race organized by the newspaper “Pravda”, the Central Committee of the Komsomol and the Council of OSOVIAJIM . “
From this moment the development of the G-39 disappeared without a trace. All information about its development has disappeared. Neither was it clear about his fate in contacts with the institute’s workers during that time. Possibly all this is linked to the process that followed the dissolution of the institute and the repression linked to the arrest of MN Tukhachevaski.
G-39 Powerplant: 1 × 100 hp M-11 Wingspan: 6.80 m Wing area: 14.20 m² Length: 8.84m Height: 3.16m Empty weight: 520 kg Maximum takeoff weight: 698 kg Accommodation: 1
