Re: Paper Your Walls

OK, we'll do both.

There is a nice little museum near the Hartford airport that has some engines. And some old wooden propellers, which kicked off Hamilton Sunstrand.

Pratt and Hamilton became parts of UTC. UTC has recently acquired or merged with BF Goodrich, Raytheon, and Collins.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics

You think that's an engine? That's not an engine. This is an engine...

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  Rick C. 

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Or part thereof :-)

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Rheilly

Rick C wrote in news: snipped-for-privacy@googlegroups.com:

Nope. That is a motor. (part of).

Lycoming whacked it.

Local Favorite wrote in news:qs1t1n$d3g$ snipped-for-privacy@gioia.aioe.org:

He was doomed to be whacked by that.

If sheer size alone is your thing then good luck with that. It's got a nut missing from the top cowling, BTW. I wouldn't want a picture of that thing on my wall. No imagination nor character whatsoever in evidence in that design.

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The XR-7755 has significantly more bigness, approaching twice the displacement and weight.

It has nine cylinders per row, thirty-six total. Your spindly P&W has seven cylinders per row, just twenty eight total.

But the size isn't "alone". The camshafts can be shifted between two profiles, for max takeoff or cruise power. There are contrarotating props, with two speed ranges in the speed reduction gearing. Liquid cooling.

I saw that too. Blame the Smithsonian, Lycoming didn't lose the nut.

But, but, you were swooning over "sheer audacity" of design before!

The air-cooled P&W does present more lumpy stuff to look at. The Lycoming appears comparatively bland because it's water cooled and you're only seeing the surface. And being the only one in existence, it isn't going to be cut and sectioned to offer a peek inside.

And those are *overhead* cams!

On second glance, I don't think it does. Look at the bosses for the studs cast into that cone. The spacing is closer there, and that one stud is a bit shorter than all the others.

The XR-7755 was an over-the-top, outrageous, clean-sheet-of-paper design.

P&W's imagination... grabbing more of the familiar old stuff from the parts bins. They knew that the rear cylinders were going to overheat, they built it anyway, and the rear cylinders overheat. If jets hadn't arrived, P&W's next piston design would have been a copy of the Lycoming.

Local Favorite wrote in news:qs6ehb$1j30$ snipped-for-privacy@gioia.aioe.org:

Ok. I see 4 per row, nine rows.

Radially speaking, it would be 4 banks of 9 radial arrays sandwiched together.

Nine 4 cylinder rows at 40 degrees shift per row. 360 degrees.

A "circle of cylinders" (or radial array) is a row. I don't like it, I want rows to be straight lines, but that's the way it is. The XR-7755 has banks because cylinders in the rows happen to line up, unlike with air-cooled arrangements.

There are an odd number of cylinders in a row, so that each of a

4-stroke's cylinders will fire every-other revolution. 1-3-5-7-9-2-4-6-8 ... If the number were even, then half the cylinders, the same half every time, would be skipped.

Wikipedia pages also have row/bank terminology mixed up, about as often as they have it right.

Local Favorite wrote in news:qs8qjv$iqu$ snipped-for-privacy@gioia.aioe.org:

Well, put those idiots all in a row and shoot them.

Put me in a bank and give me all the money there.