Ack! My ACK!

Russell Kent wrote:

An inch or two of mercury from ram air at 225 kts? I think you're dreaming.
Ideally speaking, dynamic pressure at 200 MPH is 104 pounds per square foot or
about .722 psi. Each inch of mercury is 2.04 psi, so I'd expect just slightly less
than one inch of MP *if* you had a perfect intake diffuser. Since a perfect
intake diffuser is somewhat unlikely, I'd limit my expectations to about 0.5 inch
MP.

Richard Tasker replied:

On the planet where I live it is more like each inch of mercury is 0.5 psi (.4912 to be specific). That means your stated .722 psi is in fact approximately 1.47 inches of mercury - certainly within his estimated inch or 2.

Hmmm. Maybe I'm wrong. I figured that a standard day was 29.92 " Hg = 14.7 psi. Therefore 1" Hg = 2.04 psi. And there's where I went wrong. It's the other way around: 2.04 " Hg = 1 psi. So Dick's 1.47 " Hg is correct.
Again, that's predicated on a perfect diffuser, which is doubtful. As a SWAG, 1" Hg (70% of ideal) is probably a reasonable goal (at 200 mph); at 225kts I'd use a linear extrapolation of 1.3" Hg. 2" Hg at 225 kts is still a
dream, however. :-)

Russell "always willing to learn" Kent
++++++++++++++++++++++++++++++++++++++++++++++++

FWIW....
My old style Van's ram air delivers appx .8" MP at 180 mph.


Barnyard BOb --

Jim,

WOW! I don't think I'd take this as lightly as you. I would have a
serious problem with someone that you know carries a gun and sends
you a target to wear.

I have a AZ concealed permit and took the "class" and have a whole bunch
of respect as far as dealing with other people and a gun. I rarely
carry, only when necessary for safety, not to toy with.


Look for the antenna installation on my Tango II pages soon!!!!!!!
--
Bart D. Hull

Tempe, Arizona

Check http://www.inficad.com/~bdhull/engine.html for my Subaru Engine
Conversion
Check http://www.inficad.com/~bdhull/fuselage.html for Tango II I'm
building.

Jim Weir wrote:
Don't worry about fastglasair. The ******* is a lying sack of shingles. He
raised holy hell with me about carrying a concealed weapon in California on an
Arizona permit. When I told him that if I saw the weapon, I'd probably call
911, he went ballistic.

Today I received a package of targets I'm supposed to wear on my chest in the
vicinity of my heart (according to his instructions). The man is one bubble off
level.

In addition to being an aerodynamic and propulsion zero, the clown is one step
beyond reality.

Shine this thread on.

Jim


Barnyard BOb --
shared these priceless pearls of wisdom:


Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

--
Bart D. Hull

Tempe,Arizona

Check http://www.inficad.com/~bdhull/engine.html for my Subaru Engine
Conversion
Check http://www.inficad.com/~bdhull/fuselage.html for Tango II I'm
building.