The strange Soviet aeroplanes of Mr. Moskalev

The Soviet Union had its fair share of brilliant aeronautical engineers and aircraft designers. The likes of Ilyushin, Mikoyan, Sukhoi, Tupolev, and the rest became household names, even in the West. They’ve been immortalised with monuments, buildings, airports, and, in at least one case, mountains named after them. But one of the most innovative minds in the Soviet aerospace realm doesn’t even have his own Wikipedia page.

Alexandr Sergeevich Moskalev

Little is known about Aleksandr Sergeyevich Moskalev: where he came from, when he was born, if he preferred brandy over vodka, etc. His bio usually consists of a short blurb describing him as a young designer and lecturer who did most of his work without much (if any) support from the state, who got his start in Leningrad but soon set up shop in Voronezh. We know that his short-lived design bureau was shuttered shortly after the Great Patriotic War, after which he returned to teaching. A source that apparently discovered one of his memoirs also reveals that he blamed a different Aleksandr Sergeyevich, the one with the slightly better-known surname of Yakovlev, for one of his designs’ failures (more on that later). But that’s about it.

One thing we know for sure is that orthodoxy wasn’t in Moskalev’s ethos. He designed and built at least twenty-three aircraft and variants, and, when adding in the types he oversaw modifications of, is credited with around thirty-five distinct machines. Some were fairly conventional; most would be considered radical even in 2020. Moskalev’s lack of success can indeed often be attributed to the impracticality of his designs, though the conservative-minded bureaucrats that micromanaged all affairs of the Soviet state, loath to throw their support behind what they saw as far-fetched and futuristic (a bad word in Soviet circles) unless their hand was forced, bear some of the blame. Let’s take a closer look at what might have been had Moskalev achieved the successes of his peers.

Moskalev—sometimes transliterated “Moskalyev” or “Moskalyov”—cut his teeth in 1931 with the MU-3, also known as the SAM-2, “SAM” standing for Samolyot (aeroplane) Aleksandr Moskalev. This aircraft was a small, single-engine biplane flying boat intended as a trainer featuring a five-cylinder Shvetsov M-11 engine of somewhere between 100 and 200 horsepower fitted in the pusher configuration behind the top wing. The MU-3 was not an original design; rather, Moskalev, together with designers N.G. Mikhelson and O.N. Rozanov, modified an existing design, the Grigorovich MU-2, which was found to be overweight and sluggish. The MU-3 had a shorter bottom wing and improved hull and was over three hundred pounds lighter than its predecessor. However, a competing design, the Shavrov Sh-2, a parasol-wing amphibian, was found to have superior performance and was selected over Moskalev’s offering.

Undeterred, Moskalev set upon what would become his most successful project, the SAM-5, a single-engine, high-wing, all-metal monoplane that was also by far his most conventional design, looking somewhat similar to contemporaries like the Curtiss Robin. Moskalev promised that his remarkably lightweight aircraft would be able to carry five passengers at around 110 mph over a distance of 1,000 km (roughly 621 miles) using a 100hp M-11 engine. Convincing the state authorities that such a feat was possible proved difficult, but an endorsement from Sergei Pavlovich Korolev, destined to become one of the preeminent figures in the Soviet space program and already an influential voice in 1933, breathed life into the SAM-5 project.

Unfortunately, though the SAM-5 design was sound, the quality of workmanship on the first prototype was not, as workers at the nascent Voronezh Aircraft Factory lacked training and experience. Despite this, test flights showed promise, and the aircraft was modified into the improved SAM-5bis, with added wing struts, a slimmer fuselage, and parts of the airframe lightened by using fabric-covered plywood construction. By 1936, this variant was making extensive long-distance test flights; in October of that year, the SAM-5bis performed a 3,500-km flight from Sevastopol to Gorky (modern-day Nizhny Novgorod), with several stops in between, in a little over twenty-five hours—with just a single pilot onboard!

Moskalev would go on to improve and adapt the basic design, resulting in the SAM-5-2bis, a slightly smaller, aerodynamically superior rendition with better performance that was used on passenger flights from Moscow to Stalingrad, Tashkent, and Frunze (modern-day Bishkek, Kyrgyzstan) even into the war years. This in turn was developed into several variants powered by inline engines, including the low-wing SAM-10 and amphibious SAM-11, as well as the radial-powered SAM-25 military transport version, used as an air ambulance during World War II. Around forty of all variants were produced.
The Sigma Projects
Even before the decidedly unassuming SAM-5 took flight, Moskalev was thinking way outside the box. In fact, even in 1933, he was hypothesizing about rocket-propelled fighters and sketching ogival delta-wing concepts that could reach speeds of up to 1,000 km/h—and, eventually, exceed the speed of sound. Working closely with future rocket science pioneer Valentin Glushko at the Krasnyi Letchik factory in Leningrad, he may have been the first in the world to embark upon an endeavor to achieve supersonic flight. The rocket fighter idea was soon abandoned, as it was thought that rocket engines with sufficient thrust for a viable combat aircraft were still years away—somewhat untrue, it’d seem, as German work on the Messerschmitt Me 163 Komet began just four years later, but, considering what became of that monstrosity, it’s probably better that Moskalev quit while he was ahead.

The first of the concepts that came to be known as the Sigma projects, the SAM-4, appeared on paper as a piston-powered aircraft that was no less radical: something that looked like a persimmon leaf stuck to a propeller when viewed from above, with an offset cockpit and ovate endplates (vertical stabilizers) attached to the wingtips. These early drawings don’t do justice to just how forward-thinking Moskalev’s ideas for the aircraft truly were: he intended it to be a twin-engine machine, with 760hp Hispano-Suiza 12Y engines buried in the wing, similar to a modern stealth aircraft of the Northrop B-2 variety, driving coaxial contrarotating propellers with scimitar blades not unlike those found on the Airbus A400M.

Radical machines
Alas, the powers-that-be decided that the SAM-4 was just too radical, and it remains a paper airplane.
Drawings of the SAM-4 circulating around the Internet seem to show it having a fairly conventional two-legged retractable undercarriage, but Moskalev is known to have preferred a single-wheel (or even single-skid) arrangement to save weight. This concept did make it off the drawing board and into the air, albeit in a much less sci-fi manner. The SAM-6 airframe consisted of a rather ordinary (if a bit stubby) fuselage and empennage; the only thing that might’ve suggested anything extraordinary about it was the long, extremely broad wing fitted with the same endplates as those proposed for the SAM-4, albeit without rudders. Originally, skis were fitted under the fuselage and tail, with smaller skids attached to the wingtip fences; the aircraft would later be modified as the SAM-6bis, with enclosed cockpits and a wheel replacing the central ski. With a loaded weight of just 1,100 pounds, it performed adequately on a 65hp M-23 engine.
While the SAM-6 testbed proved that the single-wheel undercarriage concept was feasible, it would obviously not catch on; sailplanes and the U-2 spy plane are the exception rather than the rule. Moskalev did intend to use the arrangement on the next of his wild creations, but eventually opted for a more conventional approach—one of very few things conventional about the next of the Sigma projects, the SAM-7.
If you just look at the SAM-7’s forward fuselage, nothing seems terribly amiss about it. It has a sleek nose and streamlined cowling for its Mikulin AM-34 V-12 engine, which Moskalev was able to acquire while working on modifications for the Tupolev TB-3 bomber. The wingtips still feature those endplate stabilizers, but by now, you might just boil that down to one of the designer’s idiosyncrasies.
Then, it emerges completely from the hangar and…where’s the tail? There’s nothing behind the wing but what looks like a tail turret. No empennage whatsoever. The elevators, located on the inboard part of the twin-spar trapezoidal wing, were supposed to double as flaps.
Perhaps unsurprisingly, the SAM-7 didn’t perform the way Moskalev wanted it to, unless his intention was to give Soviet test pilots heart attacks. Its inherent instability meant that it was reportedly very difficult to control, which, coupled with its relatively high stalling speed of 86 mph (cue the nearest Martin B-26 laughing hysterically), meant that its testing program was short-lived and the aircraft’s full performance envelope was never explored. Only one of the aircraft, which must’ve somehow been funded by Moskalev himself as no evidence of state support or approval has been documented, was ever built.

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Now as we’ve already established, the Soviet state was less than enthusiastic about Moskalev’s forays into radical aircraft design. However, even in 1936, the Soviets were worried about falling behind the Americans. So, when some scientists at the Central Aerohydrodynamic Institute (TsAGI) became aware of US projects for flying machines that looked like they beamed down from outer space, featuring low-aspect-ratio wings and pilots seated in prone positions, the state became concerned about the possibility of a futuristic aircraft gap, and found Moskalev’s address crumpled in their wastebaskets. (In reality, the US ‘projects’ were little more than fanciful drawings in magazines that were never under any serious development consideration.)
What became of this quest was something far less impressive than Moskalev had envisaged, but still sufficiently radical: the SAM-9, known as the Strela, or “arrow.” It retained the leaflike wing shape of the SAM-4 drawings, but featured a traditional taildragger landing gear taken from the SAM-5 (originally with skis, later with wheels) and replaced the wingtip fences with a single central vertical stabilizer. In place of the Hispano-Suiza 12Y, the aircraft featured a license-built Renault 4P inline engine with a paltry output of either 140hp or 270hp, depending on the source; far from the supersonic speeds that Moskalev dreamed of just three short years earlier, the SAM-9 would achieve a maximum speed of 190 mph.
Thanks to Moskalev’s earlier work, the SAM-9 design was presented within three days (!), and a prototype was churned out in a mere seventy. Following promising wind tunnel tests at TsAGI, short hops were conducted starting in the spring of 1937. For the first flight, the controls were handed over to a budding N.S. Rybko, who would go on to break in some of the Soviet Union’s most impressive aircraft. But, in that instance, he couldn’t coax the aircraft more than twenty meters off the ground. It was soon deduced that the ogival delta wing necessitated a much higher angle of attack for low-speed flight—an extreme 22° to be exact. With this in mind, the aircraft was able to fly higher, but that angle of attack made landing it a harrowing exercise, and support was pulled later that year.

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While this was the practical end of the program that started with the SAM-4, Moskalev’s dream wasn’t dead yet. Rocket technology was advancing enough by 1944 that the original Sigma concept now appeared feasible—a perspective shared by Korolev, who once again voiced his support. The resultant SAM-29 would’ve featured the gothic delta wing and single vertical fin from the Strela, but with a sharply pointed nose and streamlined fuselage housing the Dushkin RD-2M-3V engine, propellant tanks throughout the airframe, and pair of cannons. Alas, by the time came to present the idea to the state, the war was over, and the project was deemed too revolutionary and unnecessary.
And that was the end of the Sigma project.

But Moskalev wasn’t wholly obsessed with his Sigmas. He did design a pair of promising warplanes in the 1940s, neither of which went into serial production but merit a mention. In fact, the SAM-13 fighter prototype might’ve been his most successful design of all if not for extenuating circumstances. Drawing heavy influence from the Fokker D.XXIII fighter of 1937, the SAM-13 sought to counter the problems of asymmetric power and frontal drag on a twin-engine aircraft by opting for the pusher-puller (or, more vulgarly, suck-and-blow) arrangement. With its short fuselage and twin-boom empennage, the SAM-13 looks very similar to the Dutch product, the main visual difference being that the smaller Russian product features a single vertical stabilizer centered on an oval tailplane rather than the twin tails attached to the booms on the Fokker. Had it gone into production, the SAM-13 would’ve been armed with four 7.62mm ShKAS machine guns, two in the nose and one in each wing.

The SAM-13’s streamlined design and lightweight construction (it was made mostly of wood) meant that its pair of 220hp Voronezh MV-6 (license-built Renault) inline engines gave it reasonably good performance, with flight tests reaching up to 323 mph and an estimated top speed of over 400 mph. This, combined with the engines cancelling out each other’s torque, was one benefit; however, it did have some drawbacks, as cooling the rear engine proved a challenge and it was prone to overheating, and the aircraft suffered from poor handling characteristics, had a dismal climb rate, and required a lot of ground for takeoff and landing.
This unsatisfactory performance conspired with a state policy prioritizing in-production warplanes over experimental projects to kill the SAM-13 after a few test flights. This is probably why Moskalev blamed Yakovlev, who was at the time Deputy People’s Commissar for the aviation sector and whose fighters were among those taking priority, for the SAM-13’s failure. But, ultimately, it was the Germans who put the final nail in the type’s coffin: those first flights took place on the eve of Operation Barbarossa. The prototype was destroyed as the Gromov Flight Research Institute was abandoned ahead of the German advance.
Another Moskalev design from around the same time, albeit existing only on paper, was the SAM-23 (also known as the LT) ground attack aircraft. Not to be confused with an assault glider with the same designation, this aircraft featured the twin-boom configuration of the SAM-13, again with a single vertical stabilizer intersecting the tailplane, but with only a single pusher engine, an M-11 radial of 150hp, very weak for a 1940s design. However, armed with two 20mm cannon, an equal number of 7.62mm machine guns, and up to four RS-82 air-to-ground rockets, it would’ve been quite formidable for its size.

The most curious aspect of the SAM-23, however, was its landing gear arrangement. The tailwheel was actually attached to a series of rods protruding from the nose; while retracted, it merely jutted out from behind the fuselage and functioned like any other aircraft’s. However, when lowered, the wheel and its elongated strut would roll along the ground as the aircraft flew overhead, acting as a sort of terrain-following device (we’re not entirely sure about about the concept behind this ‘whiskered undercarriage’).

So, you see, while men like Moskalev might not go down in history among the greats, the world of aviation is all the more colourful because of them. слава!

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