REFLECTOR: fun flying

[Laurence Coen]

Al,

Thanks for sharing your trip with us.  I wanted to set your mind at ease as to altitude and O2 requirements.  Blood gas exchange takes place at body temperature which is constant.  Density altitude is pressure altitude adjusted for temperature but since the absorption of O2 into the blood is a function of absolute pressure and concentration at body temperature the OAT is not a factor. Pressure altitude is the true factor in this equation but indicated altitude is close enough.  I fly into Slaida CO where my son lives and to make sure I'm OK I use a pulse oximeter.

Larry Coen
N136LC


From: Al Gietzen 
Sent: Tuesday, July 15, 2008 10:19 AM
To: reflector 
Subject: REFLECTOR: fun flying


I just returned on Friday from trip of about 2500 nm, including visits in Salt Lake City, North Dakota, and Boulder, CO.  Plane worked great, engine ran fine - even at density altitude of 16,500 over the Rockies west of Denver.  Typical cruise of 165 KTAS, and 9.5 ghp.  (I like my 20B rotary). Had good weather all the way. 



I learned that the standard Koch chart for runway requirement isn't a bit conservative for my airplane.  Taking off from Boulder (4000 ft) with density altitude near 8000 ft and full fuel didn't leave much excess runway.



Photo 1 - Air Center of Salt Lake at Muni #2 (U42) were very friendly, helpful and accommodating. Spotless hangar where they put my plane with a jet and twin turbo.  (the plane was very happy there).



Photo 2 - Crossing the divide around Rollins Pass.  I peaked at about 13,800 MSL, but density altitude was 16,400.  I was surprised to note that I was still climbing at 160 KTAS and 500 fpm and still had throttle to go. It occurred to me that the regs give O2 requirements based on indicated MSL, when density altitude must be more representative of O2 content. (Of course I wasn't above 12,500 more than a few minutes).



Photo 3 - (sent separately due to message size restriction) speaking of EFIS; I've been very happy with my twin GRT screens.  They have reliable, functional; and the customer service great.  The right screen shows the map with terrain when flying relatively low around Boulder area. All that red terrain is higher than I was.



BTW; I tried contacting Flight Watch on 122.0 three or 4 times on the trip, and never got a response. It is just me?



Just sharing some of the things you do AFTER you finish building.



Al (SE 20B RG)









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