X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 05 Apr 2013 07:58:33 -0400 Message-ID: X-Original-Return-Path: Received: from bay0-omc3-s14.bay0.hotmail.com ([65.54.190.152] verified) by logan.com (CommuniGate Pro SMTP 6.0.4) with ESMTP id 6181896 for lml@lancaironline.net; Fri, 05 Apr 2013 06:32:17 -0400 Received-SPF: pass receiver=logan.com; client-ip=65.54.190.152; envelope-from=peterpawaviation@hotmail.com Received: from BAY152-W53 ([65.54.190.187]) by bay0-omc3-s14.bay0.hotmail.com with Microsoft SMTPSVC(6.0.3790.4675); Fri, 5 Apr 2013 03:31:41 -0700 X-EIP: [sH0/cMe9pSkUgiC86FbjQyMzJlsrzsOc] X-Originating-Email: [peterpawaviation@hotmail.com] X-Original-Message-ID: X-Original-Return-Path: peterpawaviation@hotmail.com Content-Type: multipart/alternative; boundary="_373b2f9e-9ccd-4dad-813e-a68d1b013aa4_" From: PETER WILLIAMS X-Original-To: Lancair Mailing List Subject: RE: [LML] Re: Minimum MP for pressurization X-Original-Date: Fri, 5 Apr 2013 06:31:40 -0400 Importance: Normal In-Reply-To: References: MIME-Version: 1.0 X-OriginalArrivalTime: 05 Apr 2013 10:31:41.0142 (UTC) FILETIME=[C2D7CF60:01CE31E8] --_373b2f9e-9ccd-4dad-813e-a68d1b013aa4_ Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable hi there This thing about cabin pressure is interesting=3B i bought a sixteen year o= ld 4P and it was lousy on pressurization. my previous experience was with a= Cessna 340 with 4.2 differential pressure. that gave me a sea level cabin = at 10=2C500 feet after we found the leaks. in the 4P=2C Matthew found that a seam/joint behind the rear seat had never= =2C yea never been sealed. it leaked like a sieve for the last sixteen year= s=2C there was a leak around the door and several firewall leaks. so it may= well be that the plane you fly may never has had full pressure differentia= l. or it had it and over time leaks developed=3B and having maintained the = twin to a high standard=2C i know from the experience that the pressure ves= sel and systems always need attention. now i get sea level at about 12=2C500 and at 17=2C500 i have about 4=2C700 foot= cabin=3B i still think there is ground for improvement. As to speed: 17=2C500 feet 3=2C450 gross weight=2C 17.5 gph=2C 32" and 2250 rpm gives 26= 0 knots (same conditions at 3=2C850 gross 250 knots) 6=2C500 feet 3=2C450 gross 17=2C5 gph 32" and 2250 rpm gives a reliabl= e 238 knots (that one seems to never vary by more than a knot) i do not believe that my plane is leak free=3B it might be that we could do= a little better. what should be clear is that if you are not doing as well=2C it time to che= ck for leaks in the pressurization vessel. i love my 4p=2C put 62 hours in six months and will likely continue at that= rate or higher. and still learning and still cautious as hell. yours peter williams To: lml@lancaironline.net Date: Thu=2C 4 Apr 2013 14:56:53 -0400 From: pete@leapfrogventures.com Subject: [LML] Re: Minimum MP for pressurization In cruise I run my engine at 63% power=2C 23=94 map=2C 15 gph=2C 2400 rpm a= nd have no problem maintaining 5.5 psi cabin pressurization. Pete From: Dic= o Reijers [mailto:dico@internetworks.ca]=20 Sent: Wednesday=2C April 03=2C 2013 2:43 PM To: lml@lancaironline.net Subject: Minimum MP for pressurization Hello all=2C I was looking through the TSIO-550 Power Settings Chart and noticed that it= said the min MP for pressurization was 31.5".... I'm just wondering if th= is is true for all IVPs? I was up to FL170 the other day at 28.5" and the cabin was showing perhaps = 7800. Should I assume that if I was running at 31.5" that the cabin might = only have been showing perhaps 5000'? The reason I ask is because I'm thi= nking if we're at FL170 and the cabin is pushing 8000=2C then at FL250 (or = even FL210) the cabin pressure would be well over 10=2C000'. I had thought= it might have been because I have a leaky cabin or something.... but perha= ps its because I'm being too cheap with the fuel.... Thoughts? -dr --=20 Regards=2C Dico Reijers InternetWorks Ltd. 300 University Avenue Charlottetown PE=2C C1A 4M4 902-892-4671 (T) 888-368-9484 (F) www.internetworks.ca www.apartmentspei.com = --_373b2f9e-9ccd-4dad-813e-a68d1b013aa4_ Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable
hi there

This thing about= cabin pressure is interesting=3B i bought a sixteen year old 4P and it was= lousy on pressurization. my previous experience was with a Cessna 340 with= 4.2 differential pressure. that gave me a sea level cabin at 10=2C500 feet= after we found the leaks.

in the 4P=2C Matthew found that a seam/jo= int behind the rear seat had never=2C yea never been sealed. = it leaked like a sieve for the last sixteen years=2C there was a leak aroun= d the door and several firewall leaks. so it may well be that the plane you= fly may never has had full pressure differential. or it had it and over ti= me leaks developed=3B and having maintained the twin to a high standard=2C = i know from the experience that the pressure vessel and systems always need= attention.

now
i get sea level at about 12=2C500 and at 17=2C500= i have about 4=2C700 foot cabin=3B i still think there is ground for impro= vement.

As to speed:

17=2C500 feet 3=2C450 gross weigh= t=2C 17.5 gph=2C 32" and 2250 rpm gives 260 knots =3B (same conditions = at 3=2C850 gross 250 knots)
6=2C500 feet =3B 3=2C450 gross =3B&n= bsp=3B 17=2C5 gph =3B 32" and 2250 rpm gives =3B a reliable 238 kno= ts (that one seems to never vary by more than a knot)

i do not belie= ve that my plane is leak free=3B it might be that we could do a little bett= er.

what should be clear is that if you are not doing as well=2C it = time to check for leaks in the pressurization vessel.

i love my 4p= =2C put 62 hours in six months and will likely continue at that rate or hig= her. and still learning and still cautious as hell.

yours

pet= er williams

To: lml@lancaironline.net
Date: Thu=2C 4 Apr 2013 14:56:53 -0= 400
From: pete@leapfrogventures.com
Subject: [LML] Re: Minimum MP for= pressurization

In cruise I run my engine at 63% power= =2C 23=94 map=2C 15 gph=2C 2400 rpm and have no problem maintaining 5.5 psi= cabin pressurization.

 =3B

Pete

 =3B

From: Dico Reijers [mailto:dico@internetworks.ca]
Se= nt: Wednesday=2C April 03=2C 2013 2:43 PM
To: lml@lancaironli= ne.net
Subject: Minimum MP for pressurization

 =3B

Hello all=2C
I was looking through the TSIO-550 Power Settings Chart and noticed that i= t said the min MP for pressurization was 31.5".... =3B I'm just wonderi= ng if this is true for all IVPs?

I was up to FL170 the other day at = 28.5" and the cabin was showing perhaps 7800. =3B Should I assume that = if I was running at 31.5" that the cabin might only have been showing perha= ps 5000'? =3B The reason =3B I ask is because I'm thinking if we're= at FL170 and the cabin is pushing 8000=2C then at FL250 (or even FL210) th= e cabin pressure would be well over 10=2C000'. =3B I had thought it mig= ht have been because I have a leaky cabin or something.... but perhaps its = because I'm being too cheap with the fuel....

Thoughts?

-dr


--
Regards=2C

Dico Reijers

In= ternetWorks Ltd.
300 University Avenue
Charlottetown
PE=2C C1A 4M4=

902-892-4671 (T)
888-368-9484 (F)

www.internetworks.ca
www.apartmentspei.com

= --_373b2f9e-9ccd-4dad-813e-a68d1b013aa4_--