PPRuNe Forums - Heikkis' Silhouette Challenge

Ah, bugger! That's the one Graeme!!! As this is the only know photo it I thought it would last a while... clearly not!! NOYADE HAS CONTROL

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

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 Ostechbureauto be built. Following general concept of P.I.Grokhovskij (patented February 25, 1935), it was not a pure experimental machine, but a fighterprototype. One of very uncommon appearance and unusual armament.

It was a specialized ramming fighter. First, it supposed to carry apneumatic gun in the long nose boom. This boom could be also used to tear holesin enemy zeppelins and blimps. Two steel wires running from the nose boom tothe 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 withvertical takeoff. The concept was patented by P.I.Grokhovskij as "Installation of the powerplant in thecentral 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 hiscolleagues had. As a man of practical solutions, P.I.Grokhovskij could sacrifice his ambitions in favour ofsolving the problem. Three skilled designers ('professors' V.F.Bolkhovitinov, S.G.Kozlov, A.E.Kaminov) were invited tojoin Ostechbureau for this Programm. They were attracted by bothterms 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 withdear-drop shaped canopy. Windshield was protected by (retractable?) steel plate- bullet deflector, since G-39 supposed to approach close to enemy planes forramming.

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

Four-point fixed landing gear included small main wheels on long strutsattached at the wing roots and small outriggers at the wing trailing edge, nearwingtips.

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

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

Shortage of experienced workers and poor technological base of the TsAGI workshop forced to simplify design 'on the fly' duringassembly. Cockpit canopy was replaced by small windshield. Ramming armament wasnot fitted. Even oval cutout in the wing was straightened, and wing wastransformed from triangular to swept. None of the trial witnesses noticed VTOL enginemounts...

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

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