At the National Summer Steamup Jeff Williams was kind enough to let me
inspect the valve gear on his C-16. I had a question about why prototype
Stephenson valve gear had two eccentrics per cylinder that each drove
one end of the expansion link. The C-16 has only one eccentric per cylinder.
Steve asked:-
At the National Summer Steamup Jeff Williams was kind enough to let me
inspect the valve gear on his C-16. I had a question about why prototype
Stephenson valve gear had two eccentrics per cylinder that each drove
one end of the expansion link. The C-16 has only one eccentric
Steve,
I cannot say for sure about the C-16, but the reason that the Aster C7S
Mogul has only one eccentric, is because it isn't Stephenson's Link
motion! It is a modified form of Walchaerts gear, but without and anchor
and union link to impart the lap and lead functions to the valve,
sepeartely
At 11:57 AM 8/31/04 -0400, you wrote:
[snip a true Stephenson's Link Motion ALWAYS has two eccentrics,
So, to make it short, if there is only one eccentric, it isn't Stephenson's
[snip] So unless you make an exhaustive study of valve gears, some can be
a bit difficult to identify.
Sincerely Keith
From: Harry Wade [EMAIL PROTECTED]
snip
Without laborious study of the ancient texts (which I ain't about to
do anytime soon) I can't say whether you are close or correct but IMLHO a
single eccentric does not a Stephenson's gear make. I'd say that permutes
it into something else but what I
Mike, Keith, and Harry:
Thank you for the quick response. I got curious after comparing the
Stephenson valve gear on my Graham single vertical to the C-16's valve gear.
I consulted a couple of ancient, dusty, and dog-earred tomes, Harry,
both of them had good diagrams but lacked sufficient
