How are/were computers used in jet engine design?

[orb_yt]

Hello all,

I have been tasked with writing a very short article regarding the use of computers and software in early jet engine design up to modern times.

I've been having a relatively hard time finding reading material through Google. I understand that modern jet engine designers use CAD software like SolidWorks or CATIA, and I've come across some software called Ansys Fluent which is used for computational fluid dynamics.

I'm looking for resources to help me continue to learn (at least at a high level) how computers and software have been used to design early jet engines (~1960s, ~70s or even ~80s) up to current techniques.

P.S. If this is not the correct forum for this question, please let me know. It seemed like the most suitable of the different engineering forums.

 

[anorlunda]

Wow, what a broad question. You might as well ask how paper and pencils are used.

 

[orb_yt]

Wow, what a broad question. You might as well ask how paper and pencils are used.

Then help me narrow it down. For example, the GE J79 turbojet used on the B-58 hustler, F-104 and the F-4 Phantom II was originally produced in the mid 50s and continued production through the 1960s. Given that CAD software like CATIA wasn't available till nearly the 1980s, or SolidWorks until the 1990s, how might of computers been used to design and test these early jet engines?

 

[jackwhirl]

I think you realize that there's a point you could go back to where electric computers were not used to design, build, or test aircraft. To @anorlunda's point, there is no aspect of aircraft design, manufacture, or testing that is not touched by computers at this time.

Since it is meant to be a short article, you're probably getting pretty close. Do you think the CAD angle would provide sufficient material? You could start with what drafting used to involve, the tools and their uses, and move from that to the introduction of CAD and how it has become more capable over time. (i.e. 2D to 3D, integration of CFD and/or FEA)

 

[orb_yt]

I think you realize that there's a point you could go back to where electric computers were not used to design, build, or test aircraft. To @anorlunda's point, there is no aspect of aircraft design, manufacture, or testing that is not touched by computers at this time.

Since it is meant to be a short article, you're probably getting pretty close. Do you think the CAD angle would provide sufficient material? You could start with what drafting used to involve, the tools and their uses, and move from that to the introduction of CAD and how it has become more capable over time. (i.e. 2D to 3D, integration of CFD and/or FEA)

Was there no intermediate step between no computers and CAD software being used? I would have assumed early designers may have used early computers to compute complex calculations during the design or testing phases, such as calculating aerodynamic properties.

 

[anorlunda]

Was there no intermediate step between no computers and CAD software being used? I would have assumed early designers may have used early computers to compute complex calculations during the design or testing phases, such as calculating aerodynamic properties.

We used analog computers, mechanical calculators, electronic calculators, card tabulating machines, and slide rules. Gradually, they were replaced with computers and custom software. When I say we, I mean all engineers in all fields, not just J79 designers. I never heard the word CAD until the 70s.

 

[jackwhirl]

Was there no intermediate step between no computers and CAD software being used?

You'd be better served looking into a book about the history of computers, I think, than one about aircraft to learn more about what they were capable of. But beside that, what kind of scope do you want your article to have? If you mention a dozen things that computers made easier without going into details it will be a listicle. If you have the details on a dozen things then you've written a book.

 

[orb_yt]

We used analog computers, mechanical calculators, electronic calculators, card tabulating machines, and slide rules. Gradually, they were replaced with computers and custom software. When I say we, I mean all engineers in all fields, not just J79 designers. I never heard the word CAD until the 70s.

How were analog computers used for design/testing?

You'd be better served looking into a book about the history of computers, I think, than one about aircraft to learn more about what they were capable of. But beside that, what kind of scope do you want your article to have? If you mention a dozen things that computers made easier without going into details it will be a listicle. If you have the details on a dozen things then you've written a book.

I gave a short presentation on the history of jet engines..ranging from the He 178 (worlds first turbojet powered aircraft) and Frank Whittles contributions, to later century fighters and bombers, to modern jet airliners using efficient turbofans. This article is a supplement to that brief presentation.

The scope of the article can be fairly broad, I really would just like to incorporate how computers we're used to aid in jet engine design and testing. Finding information on that topic for earlier periods (1960s, 70s, etc) has been tricky.

 

[anorlunda]

Analog computers were used to solve differential equations. Time based transients.

 

[orb_yt]

Analog computers were used to solve differential equations. Time based transients.

When designing, building, or testing a jet engine, for what tasks would you need to use an analog computer to solve a differential equation or equations involving time based transients?

 

[anorlunda]

When designing, building, or testing a jet engine, for what tasks would you need to use an analog computer to solve a differential equation or equations involving time based transients?

You ask an engineer what tasks need equations, WTF.

I'm afraid you don't have the perspective to write this article. You need to understand what engineering Is and what engineers do.

 

[orb_yt]

You ask an engineer what tasks need equations, WTF.

I'm afraid you don't have the perspective to write this article. You need to understand what engineering Is and what engineers do.

No, I asked the following:

When designing, building, or testing a jet engine, for what tasks would you need to use an analog computer to solve a differential equation or equations involving time based transients?

 

[anorlunda]

As a writer, for which writing tasks do you use words? That illustrates how your questions sound to me. The flippant answer is all tasks.

Slide rules were far more useful than analog computers. Why didn't you ask about them?

 

[orb_yt]

As a writer, for which writing tasks do you use words? That illustrates how your questions sound to me. The flippant answer is all tasks.

Slide rules were far more useful than analog computers. Why didn't you ask about them?

I did not ask about slide rules because my research is focused on the usage of computers in jet engine design. You're more than welcome to talk about how slide rules are used when designing engines.

You asked:

As a writer, for which writing tasks do you use words?

I would use them for writing articles, essays, a letter, a book, and so on. Using this analogy, for what tasks were analog computers used when designing or testing a jet engine? Were they used to calculate aerodynamic properties? Perhaps they were used to help determine thrust levels at various engine speeds? Or maybe used for calculating the ideal physical characteristics of turbine blades?

If the following is true:

The flippant answer is all tasks.

I would assume it would be trivial to come up with a few specific examples.

 

[Nidum]

The two most computationally intensive tasks in jet engine design have always been and are today performance analysis and structural analysis .

Up to about 1958 most design calculations where done by hand . By about 1964 most engine design companies had powerful digital computer systems in regular use . The transition from no computers to powerful computers was very rapid indeed .

From the earliest days of digital computers and well into my time in the industry all software was written in house . Mostly by the engineers themselves .

Where I was there were two programming languages available . FORTRAN for the heavy number crunching and a BASIC like language with extended features for more like programmable calculator uses .

FORTRAN programmes ran on the big computers in batch mode . The BASIC like language was used live at a teletype terminal connected to one of the smaller computers .

 

[orb_yt]

The two most computationally intensive tasks in jet engine design have always been and are today performance analysis and structural analysis .

Up to about 1958 most design calculations where done by hand . By about 1964 most engine design companies had powerful digital computer systems in regular use . The transition from no computers to powerful computers was very rapid indeed .

From the earliest days of digital computers and well into my time in the industry all software was written in house . Mostly by the engineers themselves .

Where I was there were two programming languages available . FORTRAN for the heavy number crunching and a BASIC like language with extended features for more like programmable calculator uses .

FORTRAN programmes ran on the big computers in batch mode . The BASIC like language was used live at a teletype terminal connected to one of the smaller computers .

Very interesting, thank you. When you say some of the most computationally intensive tasks are structural analysis, I assume you mean tasks like finding the max loads/temperature that something like a compressor blade could withstand, correct? What other components might you perform structural analysis on? What aspects of performance were commonly analyzed?

 

[Nidum]

Look through some of this : https://docs.google.com/file/d/0Bx0MqOfev7dnS01DMmtqSmhoVmc/view

 

[JBA]

Go to the following for the early history of the first computer FEA program used in aerospace design.

https://en.wikipedia.org/wiki/Nastran

 

[orb_yt]

Look through some of this : https://docs.google.com/file/d/0Bx0MqOfev7dnS01DMmtqSmhoVmc/view

Very cool. I've nearly completed a book on the Pegasus engine, this looks like a good supplemental read.

Go to the following for the early history of the first computer FEA program used in aerospace design.

https://en.wikipedia.org/wiki/Nastran

Will give that a read, thanks!

 

[bigfooted]

You could check the technical reports server of NASA and see what simulations they did on jet engines in the past:

https://ntrs.nasa.gov/

You could also check what Anthony Jameson has to say about the history of computational fluid dynamics, he's an authority because he was involved in most of it:
http://aero-comlab.stanford.edu/Papers/NASA_Presentation_20121030.pdf

 

[orb_yt]

You could check the technical reports server of NASA and see what simulations they did on jet engines in the past:

https://ntrs.nasa.gov/

You could also check what Anthony Jameson has to say about the history of computational fluid dynamics, he's an authority because he was involved in most of it:
http://aero-comlab.stanford.edu/Papers/NASA_Presentation_20121030.pdf

Great suggestions, thank you. That Antony Jameson presentation is quite interesting, i'll be sure to look it over.