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Dynon's OAT sensor
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Jaybannist(at)cs.com
Guest

Posted: Sat Mar 08, 2008 10:39 am Post subject: Dynon's OAT sensor

Out of curiosity, I just took my electronic temp probe out into the sunlight.  In the shade it read 45.3 degF; in the sun, 73.9 degF after about 4 minutes.



Jay in Dallas

do not archive



David Downey <planecrazydld(at)yahoo.com> wrote:



 	  Quote: 	
		  ...could be - but the purpose is to give a reading while flying - and it would take a very black probe and flying very near the sun to have more than a very very small influence after the first several minutes of flight.



Jaybannist(at)cs.com wrote: 



Dave,



If I'm not mistaken, those probes were shielded so that the probe was not exposed to direct sunlight.  The Dynon probe is not shielded.



Jay in Dallas

Do not archive

David Downey 

 wrote:



>I would have thought that the OAT was intended to read OAT - in flight. In the past the probes were direct reading dial thermometers and on many aircraft stuck right through the canopy bow.

>

>Dave Nixon  wrote: 

>

>I mounted mine in the fuselage bottom in the access hole of the co-pilot's seat just aft of the main carry thru spar.  This keeps it out the sun (very important) and away from the exhaust gas.  It works very good. 

>Dave Nixon

>

>

>Read this topic online here:

>

>http://forums.matronics.com/viewtopic.php?p=168400#168400

>

>

>

>  Dave Downey

>  Harleysville (SE) PA

>  100 HP Corvair

>       

>---------------------------------

>Be a better friend, newshound, and know-it-all with Yahoo! Mobile.  Try it now.

>

  Dave Downey

  Harleysville (SE) PA

  100 HP Corvair

       

---------------------------------

Never miss a thing.   Make Yahoo your homepage.

planecrazydld(at)yahoo.co
Guest

Posted: Sat Mar 08, 2008 11:26 am Post subject: Dynon's OAT sensor

very good point. 

Craig Payne <craig(at)craigandjean.com> wrote:[quote]            <![endif]-->       <![endif]-->     Well in my instrument (MGL Enigma) the OAT drives the density  altitude display – something I want to know *before* I try to take off.

  -- Craig

    From: owner-zenith-list-server(at)matronics.com [mailto:owner-zenith-list-server(at)matronics.com] On Behalf Of David Downey

 Sent: Saturday, March 08, 2008 10:47 AM

 To: zenith-list(at)matronics.com

 Subject: Re: Re: Dynon's OAT sensor

  ...could be - but the purpose is to give a reading while flying - and it would take a very black probe and flying very near the sun to have more than a very very small influence after the first several minutes of flight.

 Jaybannist(at)cs.com wrote:

  --> Zenith-List message posted by: Jaybannist(at)cs.com

 Dave,

 If I'm not mistaken, those probes were shielded so that the probe was not exposed to direct sunlight. The Dynon probe is not shielded.

 Jay in Dallas

 Do not  archive

 David Downey wrote:

 >I would have thought that the OAT was intended to read OAT - in flight. In the past the probes were direct reading dial thermometers and on many aircraft stuck right through the canopy bow.

 >

 >Dave Nixon wrote: --> Zenith-List message posted by: 

   	  Quote: 	
		    http://www.matronics.com/Navigator?Zenith-List 	
0 	  Quote: 	

1 	  Quote: 	

2 	  Quote: 	

3 	  Quote: 	

4 	  Quote: 	

5 	  Quote: 	

6[quote][b]Be a better friend, newshound, and  [quote][b]

planecrazydld(at)yahoo.co
Guest

Posted: Sat Mar 08, 2008 2:20 pm Post subject: Dynon's OAT sensor

My answer (worth exactly what I charged for it!) was based on the documented facts that our rotor blades cool rapidly as soon as they start turning. If they did not (and they have been instrumented to prove they do) the materials we engineered them from would fail structurally very soon after loading. My error was in making the assumption that the passing air would remove heat from the probe?

Jaybannist(at)cs.com wrote:[quote] --> Zenith-List message posted by: Jaybannist(at)cs.com

Dave,  I don't understand why flying would influence a temperature probe. Probes are not sensitive to "wind chill" or "heat index".  They ARE influenced by direct sunlight, which is why temps are always taken in the shade (if they are to be accurate).

Jay in Dallas  

David Downey  wrote:

[quote]...could be - but the  purpose is to give a reading while flying - and it would take a very black probe and flying very near the sun to have more than a very very small influence after the first several minutes of flight.

Jaybannist(at)cs.com wrote: --> Zenith-List message posted by: Jaybannist(at)cs.com

Dave,

If I'm not mistaken, those probes were shielded so that the probe was not exposed to direct sunlight.  The Dynon probe is not shielded.

Jay in Dallas

Do not archive

David Downey 

 wrote:

>I would have thought that the OAT was intended to read OAT - in flight. In the past the probes were direct reading dial thermometers and on many aircraft stuck right through the canopy bow.

>

>Dave Nixon  wrote: --> Zenith-List message posted by: "Dave Nixon" 

>

>I mounted mine in the fuselage bottom in the access hole of the co-pilot's seat just aft of  the main carry thru spar.  This keeps it out the sun (very important) and away from the exhaust gas.  It works very good. 

>Dave Nixon

>

>

>Read this topic online here:

>

>http://forums.matronics.com/viewtopic.php?p=168400#168400

>

>

>

>  Dave Downey

>  Harleysville (SE) PA

>  100 HP Corvair

>       

>---------------------------------

>Be a better friend, newshound, and know-it-all with Yahoo! Mobile.  Try it now.

>

  Dave Downey

  Harleysville (SE) PA

  100 HP Corvair

---------------------------------

Never miss a thing.   [quote][b]

601zv(at)ritternet.com
Guest

Posted: Sun Mar 09, 2008 1:49 pm Post subject: Dynon's OAT sensor

What does it read in the sun in a 100mph airstream?



---

Jaybannist(at)cs.com
Guest

Posted: Sun Mar 09, 2008 2:53 pm Post subject: Dynon's OAT sensor

I can't answer that 'cause I don't have a 100 mph airstream in my back yard.  An aircraft's temperature probe, sitting on the ramp, is not in a 100 mph airstream, either. Wouldn't you like an accurate temperature reading on the ground BEFORE charging off into a high density situation?



Jay in Dallas

Do not archive

"Robin Bellach" <601zv(at)ritternet.com> wrote:



[quote]



What does it read in the sun in a 100mph airstream?



---

601zv(at)ritternet.com
Guest

Posted: Sun Mar 09, 2008 3:34 pm Post subject: Dynon's OAT sensor

Most certainly, and I'm planning to avoid a sunny location. I was just 

curious about what effect the cooling airstream might have for in flight 

readings if someone did do a sunny mount, and thought someone knowledgeable 

might chime in. I would guess that the cooling airstream would for the most 

part offset the sun heating, but was wondering if, as is frequently the 

case, I'm guessing wrong.



---

rsteele(at)rjsit.com
Guest

Posted: Sun Mar 09, 2008 3:58 pm Post subject: Dynon's OAT sensor

If you are sitting on hot pavement, seems to me the heat coming off  

the pavement going to affect reading too.  You could have a little  

oven between the skin and the pavement.  I'm not saying this is worse  

than the sun, just that like everything else about flying, it's a  

compromise.



Ron

On Mar 9, 2008, at 5:45 PM, Robin Bellach wrote:



[quote] 

 <601zv(at)ritternet.com>



 What does it read in the sun in a 100mph airstream?



 ---

Jeyoung65(at)AOL.COM
Guest

Posted: Sun Mar 09, 2008 7:22 pm Post subject: Dynon's OAT sensor

I think you are correct. The wind will transfer the heat from radiated heat  and bring your reading down to air temp.   Jerry of Ga.DO NOT  ARCHIVE

  

  In a message dated 3/9/2008 7:35:07 P.M. Eastern Daylight Time,  601zv(at)ritternet.com writes:

  	  Quote: 	
		  -->    Zenith-List message posted by: "Robin Bellach"    <601zv(at)ritternet.com>



Most certainly, and I'm planning to avoid a    sunny location. I was just 

curious about what effect the cooling airstream    might have for in flight 

readings if someone did do a sunny mount, and    thought someone knowledgeable 

might chime in. I would guess that the    cooling airstream would for the most 

part offset the sun heating, but was    wondering if, as is frequently the 

case, I'm guessing  wrong.



	




It's Tax Time! Get tips, forms and advice on AOL Money & Finance.

  [quote][b]

planecrazydld(at)yahoo.co
Guest

Posted: Mon Mar 10, 2008 2:21 am Post subject: Dynon's OAT sensor

we discovered that the hottest surface on a 737 was the underside of the polished horizontal stabilizer when the aircraft was parked at a particular orientation on blacktop.



Ronald Steele <rsteele(at)rjsit.com> wrote:[quote] --> Zenith-List message posted by: Ronald Steele 



If you are sitting on hot pavement, seems to me the heat coming off  

the pavement going to affect reading too.  You could have a little  

oven between the skin and the pavement.  I'm not saying this is worse  

than the sun, just that like everything else about flying, it's a  

compromise.



Ron

On Mar 9, 2008, at 5:45 PM, Robin Bellach wrote:



[quote] --> Zenith-List message posted by: "Robin Bellach"  

 <601zv(at)ritternet.com>



 What does it read in the sun in a 100mph  airstream?



 ---

leo(at)zuehlfield.com
Guest

Posted: Mon Mar 10, 2008 9:56 am Post subject: Dynon's OAT sensor

45 years ago when I was a navigator in C-124s, I had to deduct 1 degree 

centigrade from the in-flight OAT reading due to air friction on the 

probe at our TAS (200K).

Jeyoung65(at)aol.com wrote:

 	  Quote: 	
		   I think you are correct. The wind will transfer the heat from radiated 

 heat and bring your reading down to air temp.   Jerry of Ga.DO NOT ARCHIVE

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