dew point?

HI,

Where does a pilot use the dew-point? Why is the volmet transmiting
this info?

Thanks
frank

wrote:

Where does a pilot use the dew-point?

A close temperature/dewpoint spread (less than 5 degree Celsius difference
between the two) can indicate the presence or possibility of fog.

--
Peter

Thanks
joe

A close temperature/dewpoint spread (less than 5 degree Celsius difference
between the two) can indicate the presence or possibility of fog.

Also, knowing the temperature and dew point one can estimate the cloud
bases (using a standard lapse rate of 2 deg/1000 feet).

Jose
--
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On Wed, 01 Mar 2006 18:22:11 GMT, Jose
wrote in : :

A close temperature/dewpoint spread (less than 5 degree Celsius difference
between the two) can indicate the presence or possibility of fog.

Also, knowing the temperature and dew point one can estimate the cloud
bases (using a standard lapse rate of 2 deg/1000 feet).

The Relative Humidity, of which due point and temperature are an
indicator, is useful in predicting induction system icing in
carbureted engines.


http://www.lycoming.textron.com/main...tionIcing.html
Every pilot who flies an aircraft powered by a carbureted engine
should be thoroughly educated about carburetor ice. They should
know that under moist conditions (a relative humidity of 50% to
60% is moist enough), carburetor ice can form with any outside air
temperature from 20o to 90oF. It is most likely in the 30o to 60oF
range. Temperatures in the carburetor can drop 60o to 70oF
(refrigerator effect) as a result of fuel vaporization and the
carburetor venturi effect. It also happens that carburetor ice
forms more readily when the engine is operated in the lower power
range. It will form while taxiing and this makes it very important
to check engine power before takeoff and to remove the ice if
necessary. Care should be taken to avoid dusty or dirty conditions
when utilizing carburetor heat on the ground.

"Peter R." wrote in message
...
wrote:

Where does a pilot use the dew-point?

A close temperature/dewpoint spread (less than 5 degree Celsius difference
between the two) can indicate the presence or possibility of fog.

A close spread like stated above could also mean that carb ice will form
more easily.
--
Jim in NC

Morgans wrote:

A close spread like stated above could also mean that carb ice will form
more easily.

Thanks, Jim.

Not having flown a carburetor-equipped aircraft since 1990 and considering
the fuel-injected BE35 I now own, I certainly overlooked the issue of carb
ice.



--
Peter

Morgans wrote:
A close temperature/dewpoint spread (less than 5 degree Celsius difference
between the two) can indicate the presence or possibility of fog.

A close spread like stated above could also mean that carb ice will form
more easily.


The same 2-3 degree difference between dewpoint and temperature may make the
difference in deciding to go or not. If it occurs as the sun is rising, going
is probably safe as the temperature is going to rise, widening the spread.
Conversely, if the sun is going down, it's a pretty good chance fog is going to
get you if you decide to fly.



--
Mortimer Schnerd, RN

VE

A dew point above about 50 F indicates that storms are
possible and above 60 F that sever storms are likely due the
available supply of latent heat.
A close spread indicates that fog is possible, also a dew
point around 60 with a air temp of 90 is a good indicator of
carb ice conditions.



--
James H. Macklin
ATP,CFI,A&P

--
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But government sees it as an obstacle to be overcome.
some support
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"Peter R." wrote in message
...
| wrote:
|
| Where does a pilot use the dew-point?
|
| A close temperature/dewpoint spread (less than 5 degree
Celsius difference
| between the two) can indicate the presence or possibility
of fog.
|
| --
| Peter

wrote:
HI,

Where does a pilot use the dew-point? Why is the volmet transmiting
this info?


A rule of thumb for the base of convection clouds
is 400 feet / degree C of temperature - dewpoint
difference.

--

Tauno Voipio
tauno voipio (at) iki fi