OT, cool books about aircraft engines

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See pics. I found the "Dependable Engines" book in an antique store in Auburn Ca, and the other one is available from Amazon.

What impresses me is how hard it is to design engines, and how relatively easy electronics is.

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John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  
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John Larkin
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I'm sure the engine folks say the same about electronics

NT

Reply to
tabbypurr

My Toyota is over 300k miles. It burns a little oil, but it always starts in a couple of rotations. All the Japanese brands seem to have excellent engines (and mediocre body rust production).

Perhaps equally impressive is what they achieved, back in the days before lubricant rheology and surface physics and synthetic blends and all that.

It's hard to argue with the success of directed evolution, over so many generations of automobile, aerospace, marine and stationary engines.

We finally have CFD with chemical equilibria today (and it was beginning to be practical for the big companies a few decades ago), which can analyze messy things like turbulent combustion, without having to build up a thing and test it (and probably destroy it in the process: see Saturn 5 development).

Still nothing to analytically understand and generate the boundary conditions to achieve a particular goal (such as homogeneity and duration of combustion), but we can at least make guesses in that space much faster than machining a new head and piston, or injector plate and combustion chamber, every time.

I recall one of the greater advances in the automotive field being Jaguar's development of a turbulent chamber giving better combustion, and that was as late as... uh, 60s?

Tim

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Seven Transistor Labs, LLC 
Electrical Engineering Consultation and Contract Design 
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Reply to
Tim Williams

I can easily measure voltages, waveforms, and temperatures almost anywhere on a running PC board. Currents are a bit more work. I can blue-wire or change a part quickly. If I blow something up, it's usually no big deal. I can iterate an entire board design in a few weeks at modest expense. If I drop a board, it doesn't hurt anything or anybody.

The MEs can only guess the temperatures and pressures and flows and stresses inside a running engine; it's hard stuff to instrument and measure. One engine test could cost a few megabucks. If it blows up, maybe months and tens of megabucks. Iterations take thousands of engineer-hours and machine shop labor.

Jet engine testing is radical. The on-ground test stands are gigantic, and few can do temperature/altitude. Most people strap a test engine onto a used 747 and fly it, along with all the test instruments and people that will fit aboard.

That's way too grown-up for me.

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John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  
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John Larkin

During WWII, Rolls Royce Merlin engines were run at full power for a couple of hours, then subjected to bursts at maximum power. A proportion of engines were taken off the production line and sripped down to check for wear, overheating, damage, etc. The engines had an enviable reliability record.

Video from the Past [24] - Rolls-Royce Merlin Engine. See around 23:30

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They did much the same thing for development.

Reply to
Steve Wilson

upto a point, yes. You can't measure inside ICs or transformers etc.

similar to electronics, on one scale you can measure it all, but you won't easily get a picture of the peak stress on each square millimeter of the cylinder head etc.

one long series of tests could

the costly part of the process is the level of testing to meet stringent requirements. One can also build and put into service engines with minimal testing, they just can't be expected to be as good.

NT

Reply to
tabbypurr

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** When RR were developing the R (racing) engine prior to the Merlin, they would push inlet boost pressure and rpms until something broke. Then they knew which part needed improving.

.... Phil

Reply to
Phil Allison

Usually I can.

No, one test. A couple of hundred people might show up from all over the world.

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John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  
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John Larkin

Why? What drama. The engine tests I showed at Rolls Royce are all that is needed. Car companies do the same thing today. They don't need multimegabuck tests. Nobody does that.

Reply to
Steve Wilson

Pratt does; I've been to their engine test facility in Hartford, which can run an engine full-blast simulating temp and altitude. A big qual test will have 80 or so Pratt engineers, a bunch of FAA people, some airline people, some airframe people, and lots of managers.

Down in West Palm Beach, they test engines outdoors. Fun stuff like throwing water and hardware and ice and chickens into a running engine, or running full-blast and blowing off a fan blade with explosives to see if the containment works. In addition to the labor and test stand and instrumentation, that totally destroys a $12 million GTF engine.

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Doesn't that look expensive? They do that test twice.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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John Larkin

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**Shame that video is about a RR Trent 900 Engine.

FYI: The above vid has been heavily edited, see much shorter & raw version here:

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..... Phil

Reply to
Phil Allison

Imagine how rough the nuclear bomb designers have it. Guess that's part of what they invented supercomputers for

Reply to
bitrex

How come so many engineers drive dumpy old beaters? Bob Pease would still be alive had he not been obsessive about a car model that will be missed by nobody on its technical merits.

A lot of "regular" people like old cars but at least they like interesting/good old cars; the Japanese econo-boxes of the 80s and 90s weren't even that great when they were new.

Unless by "Toyota" you're talking about a Toyota Supra in which case you have my apologies.

Variable valve timing and lift was patented in the late 1950s but wasn't really practical for mass production cars until it could be controlled electronically by computer

Reply to
bitrex

Why is that a shame? All the engine makers have to do that. Not everyone puts the test on Youtube.

The engine I saw the insides of had a beautiful milky-amber blanket of fiberglass, about a foot thick, wrapped around the main fan to catch the blades.

The aerospace people are great to work with.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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John Larkin

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** Its not clear at all that Bob's demise was due purely to his driving an old beetle.

Reports say the car left the road, hit a tree head on while and Bob was not wearing his seat belt.

..... Phil

Reply to
Phil Allison

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** That you posted a vid about a different maker's engine.

Plus it failed to show the event fully.

That's two shames.

Dickhead.

.... Phil

Reply to
Phil Allison

uck

Shell set up a single cylinder test engine in the UK where they could fire a laser into the combustion space and get gas flow rates at specific point and specific times. I got marginally involved when the guy setting it up wa nted Pockels cell to modulate the laser fast, which would have needed a fas t high voltage drive. Happily, he worked out that pointing the laser at the right fast rotating diffraction pattern, which he would write onto a CD RO M (which could be spun fast enough) was a much cheaper way of doing the job .

There was a megabuck of hardware tied up in that test set-up, and it got so me interesting results on getting the engine to run lean, mainly based on g etting the initial circulation swirling the right way before you fired the spark plug.

It worked well enough to get his picture into a full-page Shell ad in one o f the UK national newspapers, mainly aimed at recruiting incipient Ph.D.s

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Bill Sloman, Sydney
Reply to
bill.sloman

That's jet engines. I was talking piston.

Reply to
Steve Wilson

how?

which is a different thing to doing a test.

NT

Reply to
tabbypurr

how?

which is a different thing to doing a test.

NT

Reply to
tabbypurr

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