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  #1  
Old 07-04-2020, 11:01 AM
kaweeka kaweeka is offline
 
Join Date: May 2011
Location: Roseville
Posts: 386
Default Ceiling

Since I didn't build my -9A and do the performance flights, I always wanted to know my ceiling. Living in the Sacramento Valley, it's nice to know how high I can go to get over the mountains with room to spare. Today was a great day to do this. I took off from KLHM and called up NorCal approach, asking if they had time to help me with my quest. They gave me an area between Beale AFB and Grass Valley, initially cleared to 19,000. That came and went with requests every thousand feet untilI stopped at 24,000. My oxygen just couldn't keep up through a nasal cannula with SpO2 drifting down to 80%. That was enough for me to head down. The controller was great. I told him the book says 19,000 for a ceiling and after passing 21,000 he suggested we "go for the record". FYI, the data at 24,000 from my G3x showed 11.0" Hg, 38% hp. It's on Flightaware. I might have been able to get to 25,000 but just didn't feel comfortable with O2 trending down. Maybe I'll get a mask from my office and try it again.
Happy 4th everyone

David
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  #2  
Old 07-04-2020, 11:06 AM
Pilot135pd's Avatar
Pilot135pd Pilot135pd is offline
 
Join Date: Jan 2019
Location: Vaca Moo Airport - TA37 in East TEXAS
Posts: 1,331
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Quote:
Originally Posted by kaweeka View Post
Since I didn't build my -9A and do the performance flights, I always wanted to know my ceiling. Living in the Sacramento Valley, it's nice to know how high I can go to get over the mountains with room to spare. Today was a great day to do this. I took off from KLHM and called up NorCal approach, asking if they had time to help me with my quest. They gave me an area between Beale AFB and Grass Valley, initially cleared to 19,000. That came and went with requests every thousand feet untilI stopped at 24,000. My oxygen just couldn't keep up through a nasal cannula with SpO2 drifting down to 80%. That was enough for me to head down. The controller was great. I told him the book says 19,000 for a ceiling and after passing 21,000 he suggested we "go for the record". FYI, the data at 24,000 from my G3x showed 11.0" Hg, 38% hp. It's on Flightaware. I might have been able to get to 25,000 but just didn't feel comfortable with O2 trending down. Maybe I'll get a mask from my office and try it again.
Happy 4th everyone

David
I suggest downloading and sending the data to Savvy to get analyzed and maybe even get tips on how to make the engine perform even better for your next attempt.
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  #3  
Old 07-04-2020, 11:24 AM
SPX SPX is offline
 
Join Date: Dec 2018
Location: San Diego
Posts: 403
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Were you level long enough anywhere to allow the airplane to accelerate and note your TAS?
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  #4  
Old 07-04-2020, 11:42 AM
BobTurner BobTurner is offline
 
Join Date: Dec 2011
Location: Livermore, CA
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What was the rate of climb as you approached FL240?
Using a cannula above 18,000? is against the rules, but I am surprised your blood-Ox dropped so low. Do you recall the flow rate you were using on the O2?
  #5  
Old 07-04-2020, 01:15 PM
kaweeka kaweeka is offline
 
Join Date: May 2011
Location: Roseville
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Quote:
Originally Posted by SPX View Post
Were you level long enough anywhere to allow the airplane to accelerate and note your TAS?
No. I headed down but at 38% power, it is unlikely to be impressive.
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G3x touch
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  #6  
Old 07-04-2020, 01:17 PM
kaweeka kaweeka is offline
 
Join Date: May 2011
Location: Roseville
Posts: 386
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Quote:
Originally Posted by BobTurner View Post
What was the rate of climb as you approached FL240?
Using a cannula above 18,000? is against the rules, but I am surprised your blood-Ox dropped so low. Do you recall the flow rate you were using on the O2?
Climb rate was between 100-200 fpm. You all are right, I should have remembered the requirement for the mask.
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LIO 320 B1A, Dual LS Plasma III, AFP injection
G3x touch
Roseville, Ca
  #7  
Old 07-04-2020, 05:02 PM
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rvbuilder2002 rvbuilder2002 is offline
 
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Location: Hubbard Oregon
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Default

I think the ?book? values are extrapolated from test data for what the ceiling would be at gross weight. Anything lighter would allow higher.
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  #8  
Old 07-04-2020, 05:27 PM
Taltruda Taltruda is offline
 
Join Date: Oct 2017
Location: Las Vegas, NV
Posts: 407
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Quote:
Originally Posted by BobTurner View Post
What was the rate of climb as you approached FL240?
Using a cannula above 18,000? is against the rules, but I am surprised your blood-Ox dropped so low. Do you recall the flow rate you were using on the O2?
I didn?t realize there were rules restricting cannula use above fl180, so I looked it up. Although oxygen deprivation is pretty serious, and I applaud the OP for monitoring his levels, does FAR 23.1447 not actually apply to experimental aircraft that aren?t certified under part 23? I would think that he didn?t break any rules unless perhaps his ops limitations have a ceiling, and he should have gone back to phase 1 to expand them, but I don?t really know. Anybody care to chime in?
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  #9  
Old 07-04-2020, 05:47 PM
SPX SPX is offline
 
Join Date: Dec 2018
Location: San Diego
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Quote:
Originally Posted by Taltruda View Post
I didn?t realize there were rules restricting cannula use above fl180, so I looked it up. Although oxygen deprivation is pretty serious, and I applaud the OP for monitoring his levels, does FAR 23.1447 not actually apply to experimental aircraft that aren?t certified under part 23? I would think that he didn?t break any rules unless perhaps his ops limitations have a ceiling, and he should have gone back to phase 1 to expand them, but I don?t really know. Anybody care to chime in?
FAR 23.1447 probably is not the controlling regulation in this case (although I tend to agree, it does not apply, for a few reasons...)

The cannula itself is only approved for use up to 18,000'. Probably if you look around the documentation for the unit in question, it has a statement saying just that. The fact that the cannula is being used in an experimental aircraft most likely does not factor into the equation in this case.
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  #10  
Old 07-04-2020, 06:11 PM
Taltruda Taltruda is offline
 
Join Date: Oct 2017
Location: Las Vegas, NV
Posts: 407
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Quote:
Originally Posted by SPX View Post
FAR 23.1447 probably is not the controlling regulation in this case (although I tend to agree, it does not apply, for a few reasons...)

The cannula itself is only approved for use up to 18,000'. Probably if you look around the documentation for the unit in question, it has a statement saying just that. The fact that the cannula is being used in an experimental aircraft most likely does not factor into the equation in this case.
I don?t think a manufacturer can make a statement ?approving? or ?not approving? a product for use in an experimental. I?m sure Chevy or Subaru doesn?t ?approve? their products for aircraft. Maybe I?m wrong here, but if you comply with applicable sections of part 91, I think you?re good, no?
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