John Coplin: designing a jet engine
John Coplin describes how the design of an engine is a process of system integration, with some of the factors to consider being engine efficiency, weight, cost, service life and safety.
The whole business about the engine designer is to take this aerodynamic expertise, this structural expertise, the materials, performing and having a high creep resistance at temperatures like you’ve never seen in your life before, you’ve got so many sophisticated things that, as you progress over the years and refine and get more and more efficiency out of the engine, more power out of the engine and less money into it or much increased earning power in relation to the cost of the engine. So you are refining the aerodynamics, you’re refining the structures, you’re refining the lubrication system, the internal air cooling systems, the pressure balancing systems, the instrumentation that detects that it’s working properly, the instrumentation that’s used to control the right amount of fuelling so that you don’t over speed it and burst it and things of that sort. And so the designer, like what I was, and indeed like I continue to be, is very much looking at all of these advances, finding a way of balancing them, not so much to do one at the expense of the other but, how can I have everything that I want? How can I have it safe? How can I have the highest efficiency, the lightest weight, the lowest cost, the longest service life, the greatest ease of repairing things or changing units on the wing? How can I do it without actually ground running and checking the engines before I load passengers first thing in the morning? ‘Cause if I’ve got to ground run, I can’t ground run until after the curfew, otherwise I’ll destroy the quality of life for the people living near the airport. Now I know when we built the airport they weren’t there, but they work at the airport so they’ve come to live near it and now they’re complaining that we’re making too much noise. So I’m sorry, you’ve got to design your aero engine so that it’s safe when operated by ordinary people who don’t understand as much as you do and as much as your specialists do. It’s got to be safe, it’s got to be economic, it’s got to be planned and it’s always got to happen right, right on time, right for the money and most certainly right for the customer. So it’s a – a systems integrational thing.
- Interviewee: John Coplin
- Duration: 00:02:45
- Copyright: British Library Board
- Interviewer: Thomas Lean
- Date of interview: 1/11/2011
- Shelfmark: C1379/37
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