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Old 07-06-2018, 09:26 AM   #136
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Join Date: Jan 2018
Location: Tocumwal, NSW, Australia
Posts: 1,154
Default Re: tell a Model A related story

Radial engines. How do they work?

My apologies to you. The illustrations were supposed to be with the pertinent explanation but because I am an old fossil or computer dinosaur they ended up down the bottom. I'm sure you will figure it all out. g

To answer the question. How do they work. The question every farmer asked me.
Here is the crank and the conrod conection plus cam.The master rod is number 5 cylinder. If that fails the engine trashes itself. I have had that experience.
The cam is a ring of about 12 inches in diameter. The R985 has gear teeth on the inside of the ring and of course the lobs on the outer.

There is only one crank journal.

This is a supercharger. Piston engines have a centrifugal blower and jets have axial compressors. The PT6 have both.

Note the collector oil sump between numbers 5 and 6. This oil is pumped to the reservoir which is an airframe component. Notice the Pratt and Whitney badge on the sump.Engineers steal that on engine removal when it goes for overhaul. The push rod covers in the engine illustrated above are chromed. This massages the owners ego.
For those inquisitive people you may well find working models on youtube.
Hope you enjoyed reading that.
Attached Images
File Type: jpg radial crank 1.jpg (13.4 KB, 2 views)
File Type: jpg Radial crankshaft.jpg (12.4 KB, 3 views)
File Type: jpg radial conrod system.jpg (6.2 KB, 2 views)
File Type: jpg crank conrod system R985.jpg (11.6 KB, 3 views)
File Type: jpg centrifical blower.jpg (4.5 KB, 2 views)
File Type: jpg cam ring.jpg (10.6 KB, 6 views)
File Type: jpg r985.jpg (18.5 KB, 4 views)
I know many things,
But I don't know everything,
Sometimes I forget things.

And there are times when I have a long memory.

Last edited by; 07-06-2018 at 09:36 AM. is offline   Reply With Quote