X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from sccrmhc15.comcast.net ([204.127.200.85] verified) by logan.com (CommuniGate Pro SMTP 5.1.9) with ESMTP id 2084040 for flyrotary@lancaironline.net; Mon, 04 Jun 2007 18:54:52 -0400 Received-SPF: none receiver=logan.com; client-ip=204.127.200.85; envelope-from=wschertz@comcast.net Received: from wschertzpc (c-24-7-194-231.hsd1.il.comcast.net[24.7.194.231]) by comcast.net (sccrmhc15) with SMTP id <2007060422541501500cf6rme>; Mon, 4 Jun 2007 22:54:15 +0000 Message-ID: <43019672AD624C6998D1B1EABC7D25D2@WschertzPC> From: "Bill Schertz" To: "Rotary motors in aircraft" References: In-Reply-To: Subject: Re: [FlyRotary] Re: EC-2/EM-2 manifold pressure Date: Mon, 4 Jun 2007 17:54:13 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0027_01C7A6D1.5CC5C8B0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Windows Mail 6.0.6000.16386 X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6000.16386 This is a multi-part message in MIME format. ------=_NextPart_000_0027_01C7A6D1.5CC5C8B0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I understand that, but what I was asking: My field elevation is 700 feet. I set the altimeter needle to 700 feet, = the Kohlsman window reads (whatever it is that day), and that is the = manifold pressure that the EC-2 should be reading - isn't it? Bill Schertz KIS Cruiser #4045 ----- Original Message -----=20 From: Thomas Jakits=20 To: Rotary motors in aircraft=20 Sent: Monday, June 04, 2007 10:22 AM Subject: [FlyRotary] Re: EC-2/EM-2 manifold pressure Well Bill, if the Kolsman window is where you set your altimeter setting (mb or = inches mercury) you will never see field elevation (pressure) unless you = are at sealevel. E.g. if you have 29.92" at sealevel (and in the window) you still have = 29.92 in the window (you set it there!) when you get to 6500'. Your = actual ambient pressure is around 23.42".... (which you should be = reading on your manifold pressure gauge - engine stopped...=20 Unless, I got it wrong the last 15 years and 9500 hours - ohhh my...!! TJ =20 On 6/4/07, Bill Schertz wrote:=20 Al, thanks for the clarification on what sensor the EM2 is reading. When I set an 'old fashioned' altimeter to field elevation, the = engine is not running, isn't the Kolsman window reading the local = pressure -- ie the 'manifold' pressure?=20 Bill Schertz KIS Cruiser #4045 ----- Original Message -----=20 From: Al Gietzen=20 To: Rotary motors in aircraft=20 Sent: Sunday, June 03, 2007 11:55 AM Subject: [FlyRotary] Re: EC-2/EM-2 manifold pressure =20 Ed, When I have my EM-2 on, EC-2 off, the Manifold pressure reads the = barometric pressure (29.7 today).=20 When I then turn on the EC-2, the manifold pressure increases to = 32.9. This seems peculiar, have you noticed anything like this?=20 Bill Schertz KIS Cruiser #4045 When the EC2 is off, it is using the reading from the sensor in = the EM2. When it is on, it is reading the sensor in the EC2. I have = also found considerable disagreement on these sensors. I also found = that I had to change the calibration on the MAP pressure channel on the = EM2 to get the correct reading (with EC2 on, we don't care what the = sensor in the EM2 is reading). I have no idea why the calibration = should be different on different units that use the sam e sensor; but = there it is. You can get a vacuum gage (actually a pressure gage, so = you have to subtract from atmospheric) at a reasonable price from = McMaster-Carr, or I could loan you mine. =20 Also, it should not necessarily read the barometric pressure; you = have to adjust for altitude. Barometric is equivalent sea level (or = something like that).=20 Al ------=_NextPart_000_0027_01C7A6D1.5CC5C8B0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
I understand that, but what I was=20 asking:
 
My field elevation is 700 feet. I set = the altimeter=20 needle to 700 feet, the Kohlsman window reads (whatever it is that day), = and=20 that is the manifold pressure that the EC-2 should be reading - isn't=20 it?
Bill Schertz
KIS Cruiser #4045
----- Original Message -----
From:=20 Thomas Jakits
Sent: Monday, June 04, 2007 = 10:22=20 AM
Subject: [FlyRotary] Re: = EC-2/EM-2=20 manifold pressure

Well Bill,
if the Kolsman window is where you set your altimeter setting (mb = or=20 inches mercury) you will never see field elevation (pressure) unless = you are=20 at sealevel.
 
E.g. if you have 29.92" at sealevel (and in the window) you still = have=20 29.92 in the window (you set it there!) when  you get to 6500'. = Your=20 actual ambient pressure is around 23.42".... (which you should be = reading on=20 your manifold pressure gauge - engine stopped...
 
Unless, I got it wrong the last 15 years and 9500 hours - ohhh=20 my...!!
 
TJ

 
On 6/4/07, Bill=20 Schertz <wschertz@comcast.net> = wrote:=20
Al, thanks for the clarification on = what sensor=20 the EM2 is reading.
 
When I set an 'old fashioned' = altimeter to=20 field elevation, the engine is not running, isn't the Kolsman window = reading=20 the local pressure -- ie the 'manifold' pressure?
Bill Schertz
KIS Cruiser=20 #4045
----- Original Message ----- =
From: = Al Gietzen =
To: Rotary = motors in=20 aircraft
Sent: Sunday, June 03, 2007 = 11:55=20 AM
Subject: [FlyRotary] Re: = EC-2/EM-2=20 manifold pressure

 

 

Ed,

When I have my EM-2 = on, EC-2=20 off, the Manifold pressure reads the barometric pressure (29.7=20 today).

 

When I then turn on = the EC-2,=20 the manifold pressure increases to 32.9.  This seems = peculiar, have=20 you noticed anything like this?

 

Bill Schertz
KIS = Cruiser=20 #4045

When = the EC2 is=20 off, it is using the reading from the sensor in the EM2. =  When it is=20 on, it is reading the sensor in the EC2. I have also found = considerable=20 disagreement on these sensors.  I also found that I had to = change the=20 calibration on the MAP pressure channel on the EM2 to get the = correct=20 reading (with EC2 on, we don't care what the sensor in the EM2 is=20 reading).  I have no idea why the calibration should be = different on=20 different units that use the sam e = sensor; but=20 there it is.  You can get a vacuum gage (actually a pressure = gage, so=20 you have to subtract from atmospheric) at a reasonable price from=20 McMaster-Carr, or I could loan you mine. 

 

Also, = it should=20 not necessarily read the barometric pressure; you have to adjust = for=20 altitude.  Barometric is equivalent sea level (or something = like=20 that).

 

Al


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