A B-52 bomber in time for D-Day?

[MIflyer]

Well, we are not talking about building a F-22 in 1942 but a B-52, and not one with EVS, FLIR, and SRAM, either. And in the book they said they would build P-51's followed by F-86's and A-4's followed by F-5's. And the time travelers would not have to do it all by themselves.

But here is an interesting article that deals with the idea a bit more realistically, although using a more extreme example.

Look on page 61, the article, "No Copying Allowed": Collected editorials from Analog : Campbell, John Wood, 1910-1971 : Free Download, Borrow, and Streaming : Internet Archive

 

[Shortround6]

Ok, but how does taking a few turbine blades out of an F22 and comparing them to the turbine blades in a prototype Whittle jet tell you HOW TO MAKE the blades in a J-57?

This is almost, but not quite, equivalent to sending a group of WW II ships and sailors back to the American Civil war and trying to build even Martin B-10s and Curtiss Hawk biplanes in 2 years. The industry/infrastructure simply doesn't exist.

 

[MIflyer]

The GE J-35 axial flow jet engine was in production in 1945. The J-47 was in production in 1948.

 

[pbehn]

You cannot underestimate how much knowledge a company has within all its staff. The company that built the B-52 had progressed from the B-29 and the B-17 with many other types too. That is an awful lot of mistakes made and learned from as planes became more complex. Personally I think if you made everyone redundant who worked on the B-52 and replaced them with equally intelligent workers with no experience but all the manuals and procedures you wouldn't get a B-52 in two years and a lot of people would be killed and injured in the process. I worked in a factory that had just been mothballed for 4 years and the management kept on, it took months to get going as everyone learned what the previous workers knew.

 

[J.A.W.]

You cannot underestimate how much knowledge a company has within all its staff. The company that built the B-52 had progressed from the B-29 and the B-17 with many other types too. That is an awful lot of mistakes made and learned from as planes became more complex. Personally I think if you made everyone redundant who worked on the B-52 and replaced them with equally intelligent workers with no experience but all the manuals and procedures you wouldn't get a B-52 in two years and a lot of people would be killed and injured in the process. I worked in a factory that had just been mothballed for 4 years and the management kept on, it took months to get going as everyone learned what the previous workers knew.

True, post-war examination of Nazi-tech brought some surprises...
& one for Sid Camm, chief designer at Hawker, was that Focke-Wulf had
300 research staff dedicated to investigating 'blue-sky' (non-direct) stuff,
- while he'd had to make do with a mere handful of design staff, all of 'em horribly over-stretched..

 

[MIflyer]

Ok, but how does taking a few turbine blades out of an F22 and comparing them to the turbine blades in a prototype Whittle jet tell you HOW TO MAKE the blades in a J-57?

It's called "Math." But it is true that you probably would not build a J-57 or even a B-52 but something better.

Just knowing what you were going to do that did not work and what you did that did work is of immense value.

 

[Shortround6]

It's called "Math." But it is true that you probably would not build a J-57 or even a B-52 but something better.

Math may tell how and why the blade was shaped the way it was. It does nothing to tell "how" the blade was made. Casting/forging techniques, modern machining techniques, metallurgy and the like. Some of which are as far removed from 1942 metal working as a modern cell phone is from a 1942 rotary dial phone.

 

[Keslerian]

The Problem a lot of these time travel books have is that the "time travelers" do NOT bring all the technical information of how to produce the weapons/planes/ships they have with them.

And unfortunately for even time travel reality ( there is a real stretch in itself) the planes/engine/ computers of 2021 (or even 2001) are generations different than the even the prototype engines of 1941 so that the only things they have in common is general operating principles.
In aircraft fabrication they were using those big Hydraulic presses to bend chemically milled sheets.
Without the knowledge of how to do chemical milling the big hydraulic presses are much less useful.

I agree. It going to be a very specific piece of information, and the odds are against it being in a ships data archives. It'll be a document with some obscure and technical name, like: ''Metallurgical fabrication of the B-52 airframe.'' Or maybe: ''Engineering analysis of the P&W J57 turbine blades.''

Maybe the downtimers will get lucky, and someone in the 2021 fleet will have a PDF of this document. But if they don't, then things get alot more complicated... Reverse engineering without the requisite knowledge is really hard.

In the turbine engine there a number of generations in such things as turbine blades, some of which had nothing in common with their predecessors except shape. For instance RR went, in the years between 1972 and 1987, from an inlet temperature to the turbine of 1530degrees K to 1739 degrees K. using not only different alloys and different layouts of air passages to cool the blades but 3 different casting techniques. This is on the Civil RB 211 turbo fan.
up until 1977 the blades were investment cast in a traditional multi axis grain structure. Between 1977 and 79 they developed a way to cast the blades with very long lengthwise crystals nearly eliminating any crosswise grain boundary lines and greatly increasing tensile strength. Later they were able to make blades that were actually one large crystal.

Good point. The first mention I can find of this 'single crystal' casting method was a business week document from 1966. This is what it said specifically:

''For basic research, P&W set up a metallurgy group six years ago that now has 35 Ph.d's among its staff of 100. Earlier this year, the group came up with a method of casting nickel alloys to produce a "single-crystal" structure that is four times more durable than conventionally cast material. P&W will use the process to cast turbine blades and vanes.''

I'm guessing that the blades on the J57 engine probably didn't use these kindof production techniques... But even so, they could still be problematic for 1940s engineers to reconstruct. Without knowing the specifics, its hard to say one way or another.

Even if you had some of these to examine in a 1942 laboratory, how do you duplicate them?
Or how do you try to backdate any of their features (except for overall shape) to the materials and fabrication techniques used in WW II.

I would note that it usually took around two years (at best) during WW II from breaking ground on a new factory to actually getting mass production numbers of either engines or airframes. This was for engines/ airframes using pretty much existing technology. You can't build the factory until you know what machinery is needed to put in it and for mass production the machines have to placed in a logical order (and near whatever services are going to be needed, electrical, compressed air, steam, nitrogen supplies, etc. When I worked at P & W 40 years ago some of the machines extend down below floor level and had large cooling tanks for the cooling fluid poured on the piece and the cutter/s as the piece was worked on. Trying to move machines after they are installed is a major pain in the ass.

Yeah, going from a blank sheet to an actual, flyable B-52 bomber in 24 months is a real stretch. Granted, there were only a handful of them in Birminghams story, but that still seems implausible. Honestly, it would have been more realistic if the Americans had gone for the B-36 design. Or even a buffed out B-29. Creating an highly advanced aircraft from scratch when you don't even have all the infrastructure in place is going to run into delays. Blueprints are nice, but they don't fix other things.

 

[Shortround6]

Thank you for finding that
I may have stated it badly, but what I meant or was trying to get across was that the fabrication of the modern (post 2000?) compressor and turbine blades are probably more removed from the J57 engine than the blades of an early Whittle jet are.
A bit like trying make a 1950s tube color TV set when your only examples are this:

and a 60 in HD plasma screen.

 

[MIflyer]

Well, once again we are not talking about building a 2018 or even a 1970 airplane in 1942. Detailed design of the B-52 was under way in 1951; I have worked with some of the drawings. The design of the J-47 was begun before the end of WWII. No new materials were required for the J-47 or the J-57. They already had considerable experience with high temp nickel alloys because of the many thousands of turbosuperchargers manufactured before and during WWII. What impeded jet engine development in the early 40's was not the materials and fluid dynamics but "minor" things, like how you make a fuel spray nozzle that will ensure the fuel lights, stays lit, and burns efficiently, as well as basics like "Should you make the air from the compressor do a 180 degree turn on its way to the turbine?" Tell the people of 1942 how not to screw up and they'll get it done even faster.

If in 1975 I had known that Airresearch was shipping boost venturis they had not bothered to calibrate I could have gotten the F-111D/F fixed a lot faster. Of course, if they had stopped with silly $hit like, "Your highest priority is now is writing a report on the loss of a $27.50 flight jacket that was in the possession of an airman in another unit." that would have helped a lot too.