Superbomber B-29

[At ease]

Building the B-29:

[Hetzer 15]

I read the book on the "superfortesski" that the russians made, and so many things had to have a "liberty" taken on them...meaning they needed to substitute something, because it was totally beyond them.

The tires were so big for it, that they had nothing like it, they therefore sent people over to the states to buy spares, under the guise of agricultural vehicle use. Over 3 gross were obtained, until it was shut down by the US Government.

The plaque was hidden that showed who made it and the pride it showed for the plane, this was ripped off quickly and told to a foreman to "destroy it". He said he did, but than hid it in the basement of his house, to show to people/family...it still survives to this day!

The gun calibration system, gunfire control system(turrets) was completely beyond them and could not hope to be made or duplicated. They were shocked at its complexity. 23mm cannons were subsituted instead.

The engines took the longest time to duplicate, then their were problems with the production, because of the exacting tolerances involved.

An amazing book.

[sebfrench76]

Simply the beautest flying dildo,imo.

[broderickwells]

Originally Posted by Hetzer 15

I read the book on the "superfortesski" that the russians made, and so many things had to have a "liberty" taken on them...meaning they needed to substitute something, because it was totally beyond them.

The tires were so big for it, that they had nothing like it, they therefore sent people over to the states to buy spares, under the guise of agricultural vehicle use. Over 3 gross were obtained, until it was shut down by the US Government.

The plaque was hidden that showed who made it and the pride it showed for the plane, this was ripped off quickly and told to a foreman to "destroy it". He said he did, but than hid it in the basement of his house, to show to people/family...it still survives to this day!

The gun calibration system, gunfire control system(turrets) was completely beyond them and could not hope to be made or duplicated. They were shocked at its complexity. 23mm cannons were subsituted instead.

The engines took the longest time to duplicate, then their were problems with the production, because of the exacting tolerances involved.

An amazing book.

A large chunk of the problem was converting from US imperial measurements and grades to metric measurements and such. for example: the skin of the aircraft would have been originally specified as so many thou thick. Convert that to mm, discover that the brackets for something no longer fit. The Soviets had some experience of these problems when they started making the Lisunov Li-2, a licence-built DC-3.

[KICK]

Originally Posted by broderickwells

A large chunk of the problem was converting from US imperial measurements and grades to metric measurements and such. for example: the skin of the aircraft would have been originally specified as so many thou thick. Convert that to mm, discover that the brackets for something no longer fit. The Soviets had some experience of these problems when they started making the Lisunov Li-2, a licence-built DC-3.

that conversion thing shouldn't be a problem

25.4 mm = 1 inch and so on and the Russkies have always been great mathematicians... so it musta been something else that caused the problem... but I am sure it was not the math..

[broderickwells]

Originally Posted by KICK

that conversion thing shouldn't be a problem

25.4 mm = 1 inch and so on and the Russkies have always been great mathematicians... so it musta been something else that caused the problem... but I am sure it was not the math..

It's not the maths, it the standard settings on either side of the Barents Strait. Russians manufacture metals in standard metric gauges, and make their screws to standard metric cuts. Unfortunately, standard US imperial specs don't conveniently convert to these metric standards. This from the wiki article on the USSR version of the DC-3, the Li-2:

The Soviet Union received its first DC-2 in 1935. Although a total of 18 DC-3s had been ordered on 11 April 1936, the Soviets purchased 21 DC-3s for operation by Aeroflot before World War II. A production license was awarded to the Soviets on 15 July 1936. Lisunov spent two years at the Douglas Aircraft Company, between November 1936 and April 1939 translating the design. One of the engineers who accompanied him to Douglas was Vladimir Mikhailovich Myasishchev. The Soviet version was given the designation PS-84 - Passazhirskiy Samolyot 84, passenger airplane 84 (i.e. made in GAZ/State Plant No. 84). The design incorporated 1,293 engineering change orders on the original Douglas drawings, involving part design, dimensions, materials and processes.[4]

Despite the original intention to incorporate as few changes as necessary to the basic design,[5] the GAZ-84 works documented over 1,200 engineering changes from the Douglas engineering drawings, and it was no small task for Vladimir Myasishchev to change all dimensions from U.S. customary units to metric units.[6] Some of the changes were substantial, such as the use of the Russian Shvetsov ASh-62IR engines, a Soviet development of the nine-cylinder Wright R-1820.

The Russian standard design practice also usually mandated fully shuttered engines in order to cope with the extreme temperatures. A slightly shorter span was incorporated but many of the other alterations were less evident. The passenger door was moved to the right side of the fuselage, with a top-opening cargo door on the left side in place of the original passenger door. The structural reinforcement included slightly heavier skins necessitated since the metric skin gauges were not exact duplicates of the American alloy sheet metal. Standard Russian metric hardware was different and the various steel substructures such as engine mounts and landing gear, wheels, and tires were also quite different from the original design.

Going native is harder than you think.

[At ease]

Originally Posted by broderickwells

A large chunk of the problem was converting from US imperial measurements and grades to metric measurements and such. for example: the skin of the aircraft would have been originally specified as so many thou thick. Convert that to mm, discover that the brackets for something no longer fit. The Soviets had some experience of these problems when they started making the Lisunov Li-2, a licence-built DC-3.

Originally Posted by KICK

that conversion thing shouldn't be a problem

25.4 mm = 1 inch and so on and the Russkies have always been great mathematicians... so it musta been something else that caused the problem... but I am sure it was not the math..

Originally Posted by broderickwells

It's not the maths, it the standard settings on either side of the Barents Strait. Russians manufacture metals in standard metric gauges, and make their screws to standard metric cuts. Unfortunately, standard US imperial specs don't conveniently convert to these metric standards. This from the wiki article on the USSR version of the DC-3, the Li-2:Going native is harder than you think.

True.....it's not(wasn't) the maths or converting to metric.

Tupolev was intelligent enough and pragmatic enough to adopt changes as he saw fit, whilst ostensibly fulfilling Stalin's exhortation that everything be copied exactly.

Anyone can copy things.....just ask the Chinese.

But the difficulties came when trying to make copies of something using materials that you have not perfected yourself yet.

From that wonderful magazine "Air & Space":

pp6/7 of 10 of "Made in the U.S.S.R."

By Von Hardesty
Air & Space magazine, March 2001

.....One immense challenge was the difference between English measurements used by U.S. manufacturers and the metric system, which the Soviets used. Early on, Tupolev decided not to convert the U.S. units to the metric system, which would have been time consuming. The manufacture of aluminum panels exemplified the problem. The standard thickness of the aluminum skin on the B-29 was 1/16 of an inch (1.5875 millimeters). It was impossible for Soviet plants to fabricate metal sheets to that dimension. Tupolev opted to vary the thickness of the Tu-4’s skin between .8 and 1.8 millimeters, which actually had the effect of strengthening the aircraft’s structure in some areas. Despite such changes, the weight of the Tu-4 would turn out to be only one percent greater than the B-29. No less critical were other compromises made on electrical wiring as well as hydraulic pressure and fuel consumption.

While Tupolev remained attentive to certain external cosmetic flourishes to suggest strict compliance with Stalin’s order for an exact copy (a repair patch in the fuselage was included and the interior paint scheme duplicated exactly), he often went his own way on the more critical, less obvious components. Stalin’s acquiescence on the matter of using the metric system had been a major concession. Other concessions followed in engines, radar, and armament. Leonid Kerber aptly described the Tu-4 as an “analog” or, in this context, a facsimile of the B-29. If the airplane can be thought of has having a gentic code, the dominant genes were Boeing’s, and the recessive genes were Tupolev’s.

Among all the concessions, the choice of engines for the new Tu-4 became critical. Arkadiy Shvetsov, a Soviet engine designer, learned from Tupolev that he would not have to replicate the B-29’s powerful 2,200-horsepower Wright R-3350 engine. Instead, Tupolev approved Shvetsov’s request to fit the Tu-4 with a variant of the M-71 design (a Wright engine clone). The resulting ASh-73TK engine would boast 2,300 horsepower, but the Shvetsov design proved inadequate, at least in the initial production run, to match the performance of the Wright R-3350. There were constant problems with overheating and frequent propeller failures. The ASh-73TK design, however, was a sound one, and subsequent refinements eliminated problems.

Some duplication efforts led to surprising successes. One of the more complex units on a B-29 was the Central Station Fire Control System, the computerized remote firing system. Gunsights and controls were located with the gunners in Plexiglas blisters and were linked electronically to remote turrets housing the guns. The system incorporated complex circuitry and switches that enabled any B-29 gunner to control any of the gun turrets that he could aim properly. I.I. Toropov devoted his considerable talent and energy to this system. He succeeded, to the amazement of Tupolev and the consternation of observers in the West, who believed this advanced system was beyond the capacity of the Soviets.

No less important was the decision to substitute the Soviet NS-23 cannon for the original .50-caliber machine guns, another concession approved by Stalin. Tupolev also contended with a bomb bay that was larger than any produced in the Soviet Union. And there were enormous problems with the system that actuated the undercarriage, along with the inability of the Soviet aviation industry to produce the oversize tires for the landing gear. When faced with the task of copying the B-29’s large tires and complex gear, the Soviets used a unique approach: Agents were sent to the West to purchase them on the war surplus market.

Many myths have arisen in the West about how the Soviets built the Tu-4. Over the decades stories have circulated that the B-29 was copied in exacting and often ludicrous ways. These tales suggest that Tupolev and his team mindlessly replicated every aspect of the Boeing design. As noted, Tupolev did approve the precise copying of such details as a fuselage patch and the exact hue of the interior paint scheme found on Ramp Tramp. Some rumors circulated that even flak damage on the wings had been carefully copied, but such stories exaggerate what actually happened.

When I interviewed Leonid Kerber in 1991, he told me that these stories were partially true, although he felt Westerners did not understand the historical context or Tupolev’s motives. All these minor details in copying, according to Kerber, were a way to prevent Beria’s police from accusing the Tupolev team of ignoring Stalin’s precise instructions. No one wanted to risk arrest.....

http://www.airspacemag.com/military-...tml?c=y&page=6

[clackers]

Metric\Imperial conversion is a traditional source of expensive screw-ups:

http://www.thefreelibrary.com/MARS+O......-a060332016