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A Little Gear That Could Reshape the Jet Engine

bloomberg.com

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Re: A Little Gear That Could Reshape the Jet Engine

#11

“The Silicon Valley guys seem to have the attention span of 3-year-olds.”

Or it could be that the FAA and other airline regulatory bodies around the world (especially in UK and Europe) keep innovations from happening, and so development times can be long.

You can have an idea, but getting it into production, especially if the entire design hinges around it, is an entirely different story. From the article, the new engine is to wide to fit a number of existing planes.

Re: A Little Gear That Could Reshape the Jet Engine

#14

Earlier quoted context omitted.

Or it could be that the FAA and other airline regulatory bodies around the world (especially in UK and Europe) keep innovations from happening, and so development times can be long.

If we could distribute a new gear design which fixes flaws in some over-the-air patch it'd be a lot easier to iterate and improve. Selling thousands of engines too soon and realizing they all suffered from a critical engineering issue could bankrupt your company. There's a lot on the line!

Bankrupt your company, and probably do some serious damage to the airlines or plane manufacturers that bought them from you, and also kill a lot of people. But, you know, move fast!

Re: A Little Gear That Could Reshape the Jet Engine

#15
I wonder if instead of gearing a single large fan, you could just remove the fan from the turbine altogether, add a much larger alternator, and power several large electric external fans from each turbine? That would give you more fan area than you can get with a geared turbofan, optimal fan speed for efficiency, redundancy in case one of the fans suffered damage, allow cross-routing of power between turbines if one turbine failed, and not require quite such large fans so they'd fit under the wings more easily.

Re: A Little Gear That Could Reshape the Jet Engine

#16
post #9
post #7

> what may be most remarkable about the engines is that they took almost 30 years to develop. That’s about 15 times as long as the gestation period of an elephant Who the hell is running their analogy department?!? "Thirty years! That's a big number! We need some kind of comparison that will instantly give the reader perspective. Of course, in this, as in so many other things, the answer lies in pachydermian pregnanc…

I thought the next example was even more inane. It goes on to say: "and unimaginably longer than it takes to pop out a smartphone app".

Well, as we all know, every smartphone app takes exactly 1 year to create, and it's hard to imagine a time period 30 times longer.

Re: A Little Gear That Could Reshape the Jet Engine

#17

30 years. I do wonder if that is true. Did they actually developed it under a time period of 30 years. or do they mean it more in a way that it is a continuation of previous models.

It's more of a 'The concept is 30 years old' thing. Some of the reasons driving the commercial development only became factors in the market more recently; things like fuel efficiency and airport noise restrictions. Also, one of the less discussed advantages (as a customer) for the geared turbo fan is the decrease in expected maintenance/repair costs on the life of the engine. That's big business for engine manufacturers and there will be less of it with this design.

Re: A Little Gear That Could Reshape the Jet Engine

#18

I wonder if instead of gearing a single large fan, you could just remove the fan from the turbine altogether, add a much larger alternator, and power several large electric external fans from each turbine? That would give you more fan area than you can get with a geared turbofan, optimal fan speed for efficiency, redundancy in case one of the fans suffered damage, allow cross-routing of power between turbines if one…

This idea would unfortunately negate one of the top benefits of a high-bypass turbofan. Noise reduction.

Re: A Little Gear That Could Reshape the Jet Engine

#19
There's a long negative history of high-speed gearing. Jet engines have one big rotating unit, and that basic simplicity is good for reliability. Turboprops have a gearbox, and fragile, high-maintenance gearboxes are a long-standing problem with turboprops. Adding a gearbox without reducing reliability is a major achievement.

Re: A Little Gear That Could Reshape the Jet Engine

#20
post #9
post #7

> what may be most remarkable about the engines is that they took almost 30 years to develop. That’s about 15 times as long as the gestation period of an elephant Who the hell is running their analogy department?!? "Thirty years! That's a big number! We need some kind of comparison that will instantly give the reader perspective. Of course, in this, as in so many other things, the answer lies in pachydermian pregnanc…

I thought the next example was even more inane. It goes on to say: "and unimaginably longer than it takes to pop out a smartphone app".

Smart phones haven't even existed long enough for anyone to spend 30 years making an app for them... And the laws of physics have much better backwards compatibility than each new fly-by-night smartphone OS
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