General Information
Type G-39 Cucaracha
Function Experimental Fighter
Year 1935
Crew 1
Powerplant
Type M-11
Power at 0m 100hp
Size
Length ?m
Height ?m
Wingspan ?m
Wing area ?m2
Weights and loads
Empty ?kg
Loaded ?kg
Wing Load (kg/m2) ?
Power load (kg/hp) ?

G-39 Cucaracha by P.I.Grokhovskij, V.F.Bolkhovitinov, S.G.Kozlov, A.E.Kaminov

The only survived photo of the G-39, from the Archives of the SPb State Aviation Museum. Courtesy of Alexandr Larionov, Editor in Chief of the "Aviaciya i Vremya" magazine

In 1933 team lead by P.I.Grokhovskij started project of unusual tailless aircraft. It was not the first proposal, but the first (and only) such aircraft of the Ostechbureau to be built. Following general concept of P.I.Grokhovskij (patented February 25, 1935), it was not a pure experimental machine, but a fighter prototype. One of very uncommon appearance and unusual armament.

It was a specialized ramming fighter. First, it supposed to carry a pneumatic gun in the long nose boom. This boom could be also used to tear holes in enemy zeppelins and blimps. Two steel wires running from the nose boom to the wing tips to cut tail surfaces of the enemy aircraft. If wire fails, leading edges of the wing carried steel blades to serve same goal.

And the most unusual - rotating powerplant had to provide the G-39 with vertical takeoff. The concept was patented by P.I.Grokhovskij as "Installation of the powerplant in the central section of the fuselage".

P.I.Grokhovskij had no illusions about experience of his team. Unusual aircraft layout required much more experience than he and his colleagues had. As a man of practical solutions, P.I.Grokhovskij could sacrifice his ambitions in favour of solving the problem. Three skilled designers ('professors' V.F.Bolkhovitinov, S.G.Kozlov, A.E.Kaminov) were invited to join Ostechbureau for this Programm. They were attracted by both terms of contract and challenges of the project.

General layout of the G-39 resembled tailless aircraft of B.I.Cheranovskij. Short cigar of the fuselage was crowned with dear-drop shaped canopy. Windshield was protected by (retractable?) steel plate - bullet deflector, since G-39 supposed to approach close to enemy planes for ramming.

Leading edge of the wing had 38° sweep. Trailing edge was occupied by ailerons/flaps of large area and span. Wingtips had sharp anhedral to provide additional air cushion at low speed for short takeoff and landing. Engine with pusher propeller was installed at the rear end of the fuselage. It could be tilted vertically upwards for vertical takeoff. Of course, propeller pitch had to be inverted for this purpose!

Four-point fixed landing gear included small main wheels on long struts attached at the wing roots and small outriggers at the wing trailing edge, near wingtips.

Long thin 'legs' of main landing gear, cutting wires 'antennae', tear-drop canopy and anhedral wings provided G-39 with appearance of and insect. Following popular song of the time, aircraft received nickname 'Cucaracha'.

Construction of the prototype was carried out in quite a poor condition. G-39 was not in the official plan of the Ostechbureau, and was built in after work hours from materials saved on other projects. Team had no new (or even sufficiently powerful) engine, but they managed to obtain and restore 'well-worn' M-11.

Shortage of experienced workers and poor technological base of the TsAGI workshop forced to simplify design 'on the fly' during assembly. Cockpit canopy was replaced by small windshield. Ramming armament was not fitted. Even oval cutout in the wing was straightened, and wing was transformed from triangular to swept. None of the trial witnesses noticed VTOL engine mounts...

On the assembly stage G-39 was frequently visited by V.P.Chkalov. He was a senior test pilot of the project, and detailed knowledge of the plane was a must for him. His advice was very valuable, specially in cockpit arrangement.

In the end of Spring 1935 G-39 rolled out for trials. "Indeed, looks like a cockroach. Let's give it a try." - said Chkalov, climbing into cockpit. 'Cucaracha' was running, accelerating - but refused to leave the ground. All skills and determination of pilot failed to force G-39 to fly. When fuel tank was empty, Chkalov noticed grimly: "True cockroach. And cockroach does not fly. There is some miscalculation, or may be you just outsmarted yourself, my dear."

There were number of reasons for this failure. Aircraft was underpowered (3-4 times!). Fuselage, landing gear, wing, canopy all reduced propeller efficiency. All jobs were performed by workers with inadequate skills in unpaid time, and terrible assembly and paint quality were just the last drop. This was a big setback for P.I.Grokhovskij - even a minor hoop of the G-39 could open for him doors of the Factory N°47 with its modern equipment and skillful workers.

Despite the failure of 'Cucaracha', tailless aircraft found it way into officially approved bureau plans. Of course, it was stripped of ramming armament and VTOL capability. It became a 4-passenger plane with 100hp engine and speed of 220km/h. New aircraft had to be built in 2.5 months (!) and participate in All-Union overflight organized by newspaper 'Pravda', TsK VLKSM and TsK Osoaviakhim. Contract with 'professors' was not renewed, P.I.Grokhovskij decided to rely on his own team.

Despite project was not classified and was included into official bureau plan, it vanished from all records and memoirs. Probably it was replaced in the bureau plans by G-26 fighter (1936- 1938, V.D.Urlapov), but this is no more than a guess.

PredecessorsModifications
? Ta-1 "Taran" project
References
  • "Mysterious 'Cockroach' of Grokhovskij" by Alexandre Soloviev, published by 'Aviation and Time' magazine
  • Aviation Chronology, 1935
  • Links
  • ....

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