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| Master Connecting Rod |
Mummy mummy, why am I running around in circles?Stu was asking where they put all the connecting rods on a radial engine. Here's a picture of a master connecting rod. Only piston #1 is connected directly to the crank (that's what the big hole is for). All the other pistons connect to the master connecting rod. That's what the eight smaller holes are for.
Shut up kid or I will nail your other foot to the floor.
Got that from the same place as the picture.
A connecting rod like this would require a two piece crank, which would only be suitable for an engine with a single row of pistons. Engines with multiple rows (like a Pratt & Whitney Wasp) would require a single piece crank and a two piece rod. Which is what my Uncle had. The top and bottom haves of the master connecting rod were bolted together.
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| Picture stolen from Just An Earth-Bound Misfit. |
Update January 2017 replaced missing pictures.
OK, so what determines which 'pot' the master rod is positioned? On many US Radials, the master rod goes to number one and in a double row radial the second master rod goes to the opposite 'pot' on the rear row. On the Russian engines I work on the master rod goes to number five pot on a seven-cylinder and number six cylinder on a nine-cylinder. I read in a contemporary US Navy engine manual that the master rod is usually number one cylinder but can be positioned at other cylinders "for special reasons" but didn't say any more!! What do you reckon? John
ReplyDeletePlus, if you look at the M14P section you posted, you will see that the number one cylinder (the one at the top) has a slave connecting rod not the master rod which on an M14P is at cylinder number six.
ReplyDeleteIf you could find out what determines where the master rod goes - I will be able to slep at night! John
Because the West is straight forward, so we always start with we're number one! The Russkies, being from the East, do things for their own inscrutable reasons, like Stalin was 56 when he won the Great War, which is why they picked cylinder numbers 5 and 6. In other words, I have no idea. I wonder if it makes any difference? I supposed if you had an extra $10 grand to throw around, you could try moving the master rod to a different position and seeing what happened. Does the FAA know about this, or even care?
ReplyDelete