Not having an aviation background, I wonder what the atmospheric

pressure is

at altitudes at which these experimental aircraft actually fly. I

wouldn't

have guessed that it is nearly as low as 7.5psi. Still seems to me that

the

minimum acceptable pressure should be used for both nucleate boiling and

leak

prevention reasons.

Jon

Yvon Cournoyer wrote:

 According to the attached map, you would have to fly at 17,500 ft to

reach a pressure of about 7.5 psia. The highest I have flown with my 13B
powered Zenith is 11,220 ft. In Canada, to be legal, you have to have oxygen
to fly above 12,500 ft for more than 30 minutes. Probably other exigencies
as well,.
Yvon.

Also another tidbit of info from SAE 871042. Pump flow rate for 170-190 HP 3000 RPM
is 30 GPM and the pump runs at 8000 RPM as I recall. That is relevant to the
comment about the system pressure remaining high to prevent cavitation.

Paul Lamar

 
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