Sender: <marv@lancaironline.net> (Marvin Kaye)
To: lml
Date: Thu, 16 Jan 2003 00:26:20 -0500
Message-ID: <redirect-1990073@logan.com>
Mime-Version: 1.0
In-Reply-To: <redirect-1983502@logan.com>
References: <redirect-1983502@logan.com>
From: "Lorn H. Olsen" <lorn@dynacomm.ws>
Subject: Re: [LML] LNC2 - OAT error
Content-Type: text/plain; charset="us-ascii" ; format="flowed"

>I calibrated the OAT on my Rock Mountain Micro Encoder on the 
>ground.  However, I still noticed significant in flight errors, 
>especially in the wintertime.  On a recent flight at 19,000, with a 
>reported OAT of -25c, I was indicating -12c.
>
>Clark Baker, N250JF, LNC2 360 - 550 hrs tt (and still debugging!)

Clark,

What was your indicated speed? Are you turbo charged or not?

Don't forget to consider compressibility. Even without turbos, when 
you are flying at 19,000 ft and indicating 130 kts at standard 
temperature of -22 C with a TAS of 174 kts, there is a temperature 
rise of 4 degrees centigrade. Of course if you are turbocharged the 
temperature rise would be much higher. As a matter of fact, at 19,000 
ft and indicating 170 kts at standard temperature of -22 C with a TAS 
of 228 kts, there is a temperature rise of 7 degrees centigrade.

Why do you think that the reported temperature is the real 
temperature. I use what is reported as an indication of what is going 
on, not as actual fact.

Thanks for the info though. I am going to take a look at the inside 
end of my probe also.

Lorn
-- 
Lorn H. 'Feathers' Olsen, MAA, DynaComm, Corp.
248-478-4301, mailto:lorn@dynacomm.ws
LNC2, O-320-D1F, N31161, Y47, SE Michigan