New answers tagged

7

A performance increase after a compressor wash is expected to happen, but it does not return to the original performance as there are more degradation mechanisms at play. This answer explains that organic build-up causes a change in airfoil shape causing the recoverable performance degradation. Another source may be deposition of salts and dissolved ...


5

The compressor blades accumulate a coating of organic material from the atmosphere on the blades, which in the later stages, where the temperatures get above the material's flash point, may be mostly carbon from cooked organic material like pollen and bugs (the same sort of blackened accumulated crud you'll see on the butterfly of a late stage compressor ...


0

This is only part of the answer, but I didn't want to post it in a comment after the moderators said to keep answers out of the comments: Look at the accounting concept of a "burdened rate." It helps to remember that you don't just need 100 engineers collaborating. You need 100 engineers in a building that has to keep the lights on and heat and/or air ...


0

The existing answers do a great job at answering why jet engines are expensive to develop: because they are so complicated. Let me try to answer, why are jet engines so complicated? To understand that, we have to examine the economics of jet engines, and it comes down to fuel efficiency. Let's say that you go shopping for a new car, and one car gets 1% ...


7

Adding to other excellent answers, I'd like to focus on the nature of the research. The work involved in developing and exploring ideas that aren't just capable of resolving via computer models, are huge. As other answers note, jet engines develop at the leading edge of theory and new ideas,as well as pushing existing ones. Concrete typical example #1 ...


5

In addition to the other answers: Jet engines are not only complex, they operate on the edge of what's physically possible. For example, modern jet engines run at internal temperatures that can be higher than the melting point of the metals used. When you design a new jet engine, in order for it to be successful in the market, it has to be better than ...


3

The problem is not fundamentally about jet engines, but about building complex things in general. The reasons are the same as for building a complex software. There are only gradual differences. The question can be seen as "Why does it cost surprisingly much to create complex systems of high quality?" The main issue is complexity. The design of existing ...


12

The answers are all very good in that they detail potential costs, but let me give a different angle for looking at these types of questions. In a highly competitive environment, companies will throw as much money at a problem as it is worth for them to have it solved. In economic speak: "marginal cost equals marginal gain". When designing a new engine, one ...


3

I think most of the answers address the points quite nicely, the teams are huge and there is a lot of expensive kit involved. I'd add three more points: There is risk involved that needs to be priced in. It's not like in Pharma, but not all engines sell equally well, so you need to manage the costs across different engines and designs. These are highly ...


14

Last I checked, most scientists and engineers do not make millionaire salaries. I think it's more around 100 to 250k tops. Even if you had 100 of them working for 10 years on it, that would be 250M, or a quarter of a billion dollars. The salaries in aerospace average less than 100k, it ain't IT, but they're not the issue. You can develop a basic ...


34

Jet engines are some of the most complex machines ever created. They have to be as light, efficient, safe, and reliable as possible. There's a reason that most new airliners recently have been affected by delays from engine manufacturers. This is a hard balance to engineer when on a schedule and budget. Jet engines could certainly be cheaper to develop and ...


56

Even if we ignore the salaries of everyone involved; engineers, sales people, management, Q/A teams, manufacturing teams, more sales people, and then a few spare engineers... I don't understand. If it's just designing a jet engine, then raw materials cannot possibly be a major factor even if it's something like titanium or composites. While the raw ...


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