X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao106.cox.net ([68.230.241.40] verified) by logan.com (CommuniGate Pro SMTP 5.1.11) with ESMTP id 2242257 for flyrotary@lancaironline.net; Sat, 04 Aug 2007 12:04:19 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.40; envelope-from=alventures@cox.net Received: from fed1rmimpo02.cox.net ([70.169.32.72]) by fed1rmmtao106.cox.net (InterMail vM.7.08.02.01 201-2186-121-102-20070209) with ESMTP id <20070804160339.MXU11888.fed1rmmtao106.cox.net@fed1rmimpo02.cox.net> for ; Sat, 4 Aug 2007 12:03:39 -0400 Received: from BigAl ([72.192.132.90]) by fed1rmimpo02.cox.net with bizsmtp id Xs3f1X00K1xAn3c0000000; Sat, 04 Aug 2007 12:03:39 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: EM2 & builder issues Date: Sat, 4 Aug 2007 09:05:50 -0800 Message-ID: <000001c7d6b9$b5e53620$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C7D676.A7C46720" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3138 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C7D676.A7C46720 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Tracy wrote: Bottom line is, if you need very accurate readings, learn to calibrate = the EM2 if that is what you are using. To do this, you need a good = reference. The easiest way is to use a non-contact (infra-red) thermometer. Harbor Freight and others are now selling inexpensive ones for about $10.00. = No reason for any airplane builder not to have one. Be sure to paint the = test points on the part to be measured with a spot of flat black paint to eliminate emissivity errors=20 =20 Be careful; though. I haven't seen one for $10; but I did go to Harbor Freight about a month ago, and bought one that was on sale for $39.95 (marked down for $59). I wanted to double check the temps in and out of = the oil cooler. It didn't take me long to realize it was not reading = correctly. I have a lab grade thermometer that I then checked it against. It was = off about 10 degrees or more at room temp on any surface. At higher temps = it was off by more (30 - 40 F at about 180) on any surface with emissivity = less than about .9. It was very accurate pointed at the cooler core = (essentially a 'black body' - emissivity very close to 1.0). I returned it for a = refund. Maybe you'll have better luck. =20 I had previously borrowed one from a friend which was quite accurate, = and used it to calibrate coolant and oil temps. Air temp sensor and CHT TC channels I calibrated using ice water and hot water with the lab = thermometer in it. I used pressure gauges to calibrate MAP and fuel and water = pressure. Yes, my MAP calibration data is different than Tracy's (I guess the = pressure variation is different in FL :-).) =20 FWIW, =20 Al =20 ------=_NextPart_000_0001_01C7D676.A7C46720 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Tracy =
wrote:

Bottom line is, if you need very accurate =
readings, learn to calibrate the EM2 if that is what you are =
using.  To do this, you need a good reference.  The easiest =
way is to use a non-contact (infra-red) thermometer.  Harbor =
Freight and others are now selling inexpensive ones for about =
$10.00.  No reason for any airplane builder not to have =
one.   Be sure to paint the test points on the part to be =
measured with a spot of flat black paint to eliminate emissivity errors =

Be careful; =
though.  I haven’t seen one for $10; but I did go to Harbor =
Freight about a month ago, and bought one that was on sale for $39.95 =
(marked down for $59).  I wanted to double check the temps in and =
out of the oil cooler.  It didn’t take me long to realize it =
was not reading correctly.  I have a lab grade thermometer that I =
then checked it against.  It was off about 10 degrees or more at =
room temp on any surface.  At higher temps it was off by more (30 =
– 40 F at about 180) on any surface with emissivity less than =
about .9.  It was very accurate pointed at the cooler core =
(essentially a ‘black body’ – emissivity very close to =
1.0).  I returned it for a refund.  Maybe you’ll have =
better luck.

I had =
previously borrowed one from a friend which was quite accurate, and used =
it to calibrate coolant and oil temps.  Air temp sensor and CHT TC =
channels I calibrated using ice water and hot water with the lab =
thermometer in it.  I used pressure gauges to calibrate MAP and =
fuel and water pressure.  Yes, my MAP calibration data is different =
than Tracy’s (I =
guess the pressure variation is different in FL J.)

FWIW,

Al

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