Radial-Diametral Head

[Stuart Baly]

>The Noratlas had a 14cyl. radial with disc-valves (?).

This engine might have used Aspen (Aspin?) valves. I read about these a 
long time ago. They had a disc mounted on a vertical shaft mounted so that 
the lower surface of the disc was the upper surface of the combustion 
chamber. The disc had a hole in it, and was rotated at half engine speed, 
so that intake and exhaust ports were covered and uncovered at the 
appropriate times. Apparently the system was sorted and reliable - ports 
were opened faster and flowed better than with conventional valves, and 
with no reciprocating valve train, they revved to the moon (14000rpm from a 
250cc single in the mid 1930's)

Stuart.

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Stuart Baly
Technical Officer
Cape Grim Baseline Air Pollution Station
S.Baly at bom.gov.au
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All responses are my own and should not be mistaken
for Sagely Advice, or even Common Sense.