VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics


Go Back   VAF Forums > Education > Flight Testing
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #11  
Old 12-17-2016, 05:19 PM
snopercod's Avatar
snopercod snopercod is offline
 
Join Date: Aug 2016
Location: Asheville, NC
Posts: 2,104
Default That's what I was worried about.

Quote:
Originally Posted by Vlad View Post
Likely a very thin layer of ice is my guess.
That's what I was concerned about. I've never flown in icing conditions and don't know what it looks like (other than photos). Neither did I know that one could experience icing in clear weather. My laminar flow airfoil doesn't tolerate icing well so I was real concerned. I didn't notice any degradation in my 165 Kt TAS at the time so I just shrugged and pressed on. I reviewed the ATC audio from my Garmin Virb and they were reporting a -1 deg C dewpoint on the ground. Thanks for your opinion.
__________________
(2020 dues paid)
Reply With Quote
  #12  
Old 12-17-2016, 09:27 PM
BobTurner BobTurner is offline
 
Join Date: Dec 2011
Location: Livermore, CA
Posts: 6,797
Default

If your OAT is accurate, it is very unlikely you had icing at +5 C.
Reply With Quote
  #13  
Old 12-18-2016, 06:53 AM
snopercod's Avatar
snopercod snopercod is offline
 
Join Date: Aug 2016
Location: Asheville, NC
Posts: 2,104
Default OAT calibration unknown

Quote:
Originally Posted by BobTurner View Post
If your OAT is accurate...
I guess I need to do a single-point calibration check on my Davtron 5-in-1 to find out. Dipping the probe in some ice/water mix shouldn't be too difficult. That will give me something to do while I'm suffering through all this non-flying weather. Thanks for the idea.
__________________
(2020 dues paid)
Reply With Quote
  #14  
Old 12-18-2016, 07:07 AM
sblack sblack is offline
 
Join Date: Dec 2009
Location: Montreal
Posts: 1,456
Default

Quote:
Originally Posted by BobTurner View Post
If your OAT is accurate, it is very unlikely you had icing at +5 C.
The temp on the LE will be considerably lower due to the low static pressure at that location.
__________________
Scott Black
Old school simple VFR RV 4, O-320, wood prop, MGL iEfis Lite
VAF dues 2020
Instagram @sblack2154
Reply With Quote
  #15  
Old 12-18-2016, 08:40 AM
runt runt is offline
 
Join Date: Feb 2016
Location: CA
Posts: 10
Default Not convinced it's ice

I assume we are talking about the white area on the leading edge.

I have seen plenty of icing and that doesn't really look like icing. Notice how it doesn't come all the way to the root for one thing. It looks to stop about half way. Ice would be on all of the leading edge. The air in Colorado is pretty dry. Doubtful you would collect ice in that flight condition from what I'm seeing in the photo.

Again, if we are talking about the white area I would guess it's a reflection of the clouds in the distance. Light does funny things.

The plane I normally fly has heated (shiny) leading edges. When we go through clouds and the light is right you would swear there is a layer of ice when in reality it is simply a reflection.

Hard to say based on that picture.

Did it disappear all at once? Ice would break off in sections.
Reply With Quote
  #16  
Old 12-18-2016, 09:05 AM
scrollF4's Avatar
scrollF4 scrollF4 is offline
Moderator, Asst. Line Boy
 
Join Date: Jan 2010
Location: Flower Mound, TX
Posts: 1,473
Default

Quote:
Originally Posted by runt View Post
Did it disappear all at once? Ice would break off in sections.
Just as a point of fact: aircraft icing will indeed break off in sections particularly as it starts to melt. However, if it remains frozen while flown through clear dry air, it will tend to sublimate. Clear air sublimation is the conversion of matter from a solid (ice) directly to a gas (water vapor). Happens faster in jets, but more slowly in slower aircraft because slower speeds lesson the wind/ice friction.

I now return you to your originally scheduled topic. I can't tell what your photo is showing, sorry.
__________________
Scroll

Sid "Scroll" Mayeux, Col, USAF (ret)
52F NW Regional/Aero Valley Airport, Roanoke TX (home of DR's Van Cave)
"KELLI GIRL" N260KM RV-7A tipper
Catch her on YouTube's "Because I Fly!" channel

Exemption waived.
Proud and grateful 2020 -=VAF=- Contributor

Last edited by scrollF4 : 12-18-2016 at 03:22 PM. Reason: wrong -ation
Reply With Quote
  #17  
Old 12-18-2016, 10:31 AM
BobTurner BobTurner is offline
 
Join Date: Dec 2011
Location: Livermore, CA
Posts: 6,797
Default

Quote:
Originally Posted by sblack View Post
The temp on the LE will be considerably lower due to the low static pressure at that location.
Lower, yes. 5 C (9 F) lower? Unlikely.
Reply With Quote
  #18  
Old 12-18-2016, 03:08 PM
brad walton brad walton is offline
 
Join Date: Jul 2007
Location: Cypress, TX
Posts: 526
Default

I've always thought of a change of state from solid to vapor as being sublimation
Reply With Quote
  #19  
Old 12-18-2016, 03:23 PM
scrollF4's Avatar
scrollF4 scrollF4 is offline
Moderator, Asst. Line Boy
 
Join Date: Jan 2010
Location: Flower Mound, TX
Posts: 1,473
Default

Quote:
Originally Posted by brad walton View Post
I've always thought of a change of state from solid to vapor as being sublimation
Yep, you're right. Corrected.
__________________
Scroll

Sid "Scroll" Mayeux, Col, USAF (ret)
52F NW Regional/Aero Valley Airport, Roanoke TX (home of DR's Van Cave)
"KELLI GIRL" N260KM RV-7A tipper
Catch her on YouTube's "Because I Fly!" channel

Exemption waived.
Proud and grateful 2020 -=VAF=- Contributor
Reply With Quote
  #20  
Old 12-21-2016, 11:47 AM
snopercod's Avatar
snopercod snopercod is offline
 
Join Date: Aug 2016
Location: Asheville, NC
Posts: 2,104
Default OAT calibration OK

This morning I did a single point calibration of my OAT sensor/display. I dipped the probe in a bath of crushed ice and water, and the Davtron indicated 32F/0C. My Fluke read 32.1F. At ambient the Davtron read 43F and the Fluke read 43.1F. So the 5C reading was probably accurate. BTW, my OAT probe is located under the wing, well away from the cowling exit air. I wish I had known about Skew-T charts last year
__________________
(2020 dues paid)
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 05:29 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.