X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 06 Sep 2011 12:31:20 -0400 Message-ID: X-Original-Return-Path: Received: from p3plex1out02.prod.phx3.secureserver.net ([72.167.180.18] verified) by logan.com (CommuniGate Pro SMTP 5.4.1) with SMTP id 5115297 for lml@lancaironline.net; Tue, 06 Sep 2011 12:22:39 -0400 Received-SPF: none receiver=logan.com; client-ip=72.167.180.18; envelope-from=pete@leapfrogventures.com Received: (qmail 12456 invoked from network); 6 Sep 2011 16:21:52 -0000 Received: from unknown (HELO smtp.ex1.secureserver.net) (72.167.180.19) by p3plex1out02.prod.phx3.secureserver.net with SMTP; 6 Sep 2011 16:21:52 -0000 Received: from P3PW5EX1MB14.EX1.SECURESERVER.NET ([10.6.135.87]) by P3PW5EX1HT001.EX1.SECURESERVER.NET ([72.167.180.19]) with mapi; Tue, 6 Sep 2011 09:21:33 -0700 From: "pete@leapfrogventures.com" X-Original-To: Dico Reijers , "lml@lancaironline.net" X-Original-Date: Tue, 6 Sep 2011 09:21:22 -0700 Subject: RE: Figuring out the pressurization system IV-P -- couple of questions Thread-Topic: Figuring out the pressurization system IV-P -- couple of questions Thread-Index: AcxsfA1TNE8vCwlfTxmi0ARVPRMxhQAMm1Dw X-Original-Message-ID: <2A14E6258A8534418F5498D73CCA51EF165F4233@P3PW5EX1MB14.EX1.SECURESERVER.NET> References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: multipart/alternative; boundary="_000_2A14E6258A8534418F5498D73CCA51EF165F4233P3PW5EX1MB14EX1_" MIME-Version: 1.0 --_000_2A14E6258A8534418F5498D73CCA51EF165F4233P3PW5EX1MB14EX1_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable The rate knob sets how fast the cabin pressure will change after moving the= dial. If you are in test mode, turn the rate fully clockwise so the rate = will change more noticeably. The dukes should be set such that it pressurizes the cabin to about 700 fee= t above the field elevation on the dial, until it reaches 5.5 psi, at which= point the cabin altitude will rise in lock step with increasing airplane a= ltitude. I fly out of a sea level airport. I typically put the dial at 3000 feet ai= rport elevation. This gives me a 3700 foot minimum cabin pressure. I do t= his so that, when on a precision approach, which typically start at about 3= 000 feet, my pulling the power to capture glideslope will not pop the ears = of the plane occupants due to a loss of residual pressurization. If I am f= lying to a high altitude airport, about half way through the flight I will = reset the dial to the destination altitude plus 3000 feet. If I know for s= ure I am not going to be doing a precision approach and can descend to patt= ern altitude with at least 50% power, then I will only add 1000 feet. I set the rate knob at the 500 feet/minute rate and leave it there unless I= am doing testing. You can determine the proper position on your unit duri= ng testing by changing the dial and timing how long it takes to change the = cabin altitude 500 feet, then loosening and repositioning the know so that,= in the 500 foot position, the work RATE is lined up horizontally. If I am cruising in the flight levels where 5.5 psi will not maintain a 370= 0 foot cabin, I will set the dial at 2000 feet BELOW the flight level I wil= l be cruising at. This setting gives me a 5.5 psi cabin every time. I always do my descents at 65-70% power so as to have enough boost to maint= ain the 5.5 psi differential. Note these comments assume the brass plunger on the dukes has been adjusted= to the correct maximum pressure differential (mine is set to about 5.6-5.8= psi - this can be done while flying high - note it is very sensitive) and = your dial and pressure head are properly matched (you can correct this your= self, but it takes a few flights as it can only be changed on the ground), = as the connection between the two is not based on actual values but rather = pre-set positions. Pete --_000_2A14E6258A8534418F5498D73CCA51EF165F4233P3PW5EX1MB14EX1_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

The rate = knob sets how fast the cabin pressure will change after moving the dial.&nb= sp; If you are in test mode, turn the rate fully clockwise so the rate will= change more noticeably.

<= o:p> 

The dukes should be = set such that it pressurizes the cabin to about 700 feet above the field el= evation on the dial, until it reaches 5.5 psi, at which point the cabin alt= itude will rise in lock step with increasing airplane altitude.<= /span>

 

I fly out of a sea level airport.  I typically put= the dial at 3000 feet airport elevation.  This gives me a 3700 foot m= inimum cabin pressure.  I do this so that, when on a precision approac= h, which typically start at about 3000 feet, my pulling the power to captur= e glideslope will not pop the ears of the plane occupants due to a loss of = residual pressurization.  If I am flying to a high altitude airport, a= bout half way through the flight I will reset the dial to the destination a= ltitude plus 3000 feet.  If I know for sure I am not going to be doing= a precision approach and can descend to pattern altitude with at least 50%= power, then I will only add 1000 feet.

 

I se= t the rate knob at the 500 feet/minute rate and leave it there unless I am = doing testing.  You can determine the proper position on your unit dur= ing testing by changing the dial and timing how long it takes to change the= cabin altitude 500 feet, then loosening and repositioning the know so that= , in the 500 foot position, the work RATE is lined up horizontally.

 

If I am cruising in the flight levels where 5.5 psi = will not maintain a 3700 foot cabin, I will set the dial at 2000 feet BELOW= the flight level I will be cruising at.  This setting gives me a 5.5 = psi cabin every time.

 

I always do my descents= at 65-70% power so as to have enough boost to maintain the 5.5 psi differe= ntial.

 

Note these comments assume the brass p= lunger on the dukes has been adjusted to the correct maximum pressure diffe= rential (mine is set to about 5.6-5.8 psi – this can be done while fl= ying high – note it is very sensitive) and your dial and pressure hea= d are properly matched (you can correct this yourself, but it takes a few f= lights as it can only be changed on the ground), as the connection between = the two is not based on actual values but rather pre-set positions.

 

Pete

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