I just KNEW Ron would know that!!
Thanks, Ron.
Geoff Branch
----- Original Message -----
From: "Ron Soave" <soavero@yahoo.com>
To: "Geoff Branch" <gjbranch@comcast.net>; <spridgets@autox.team.net>
Sent: Tuesday, January 30, 2007 7:38 PM
Subject: Re: Portable generators --No LBC
> --- Geoff Branch <gjbranch@comcast.net> wrote:
>> Why is aircraft electricity such high frequency?
>
> Because they don't drug test them?
>
> It's commonly wild frequency now, btw. But it was done
> initially to save weight, as power supplies can be
> made smaller, albeit less efficient.
>
>> And for a bonus question: What are those little
>> "donuts" of blue in the
>> exhaust of high speed aircraft such as the SR71??
>
> Mach diamonds, a cool phenomenon of the exhaust gases
> being at a significantly different pressure than the
> ambient. AKA "overexpansion" when the exhaust pressure
> is lower than ambient at low altitudes. Technically,
> they are Prandtl Meyer (SP?) waves.
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