Return-Path: Received: from fed1rmmtai03.cox.net ([68.230.241.56] verified) by logan.com (CommuniGate Pro SMTP 4.2) with ESMTP id 351398 for flyrotary@lancaironline.net; Wed, 04 Aug 2004 02:13:20 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.56; envelope-from=ALVentures@cox.net Received: from BigAl ([68.107.116.221]) by fed1rmmtao02.cox.net (InterMail vM.6.01.03.02.01 201-2131-111-104-103-20040709) with ESMTP id <20040804050726.KJON18674.fed1rmmtao02.cox.net@BigAl> for ; Wed, 4 Aug 2004 01:07:26 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] May not work above 8000 MSL was [FlyRotary] Re: Oil injection, and more Date: Tue, 3 Aug 2004 22:07:47 -0700 Message-ID: <000001c479e0$fbdaeb40$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C479A6.4F7E5D30" 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 V6.00.2800.1165 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C479A6.4F7E5D30 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Subject: [FlyRotary] May not work above 8000 MSL was [FlyRotary] Re: Oil injection, and more =20 Dave may be correct, Perry. =20 Here is what I think could occur. First, The oil meter pump itself is = a positive displacement pump.=20 =20 Therefore, from the standpoint of the pump it will always disperse any = oil fed to it into the injectors and combustion chamber under some amount of pressure. However, the shaft opening that drives the pump also provides = for the oil flow from inside the Engine Front mount into the metering pump. There is a hole in the boss of the metering pump shaft (on the inside of = the front housing) that is open to the atmosphere. =20 At sea level of course this hole in the boss results in 14.7 psi of pressure on the oil in the meter shaft. So as the positive displacement pump opens a chamber - the oil flows into the chamber with the help of = this 14.7 (or what ever the differential between the pressure in the pump = chamber and the atmosphere- it will something less than 14.7 but probably = greater than 12?) and gets "squirted" toward the injectors underpressure. =20 Ed; =20 I hear what you're sayin', but I really don't think so. How much = pressure does it take to make hot oil flow through a short length of tube (or a = port in the pump) at a VERY low flow rate? Very little. We're talking a few cc/min; and I'd guess even a couple of psi, would do the job nicely. = And at 8000 ft we still have; what, about 11 psi. =20 As we go to higher altitudes it is probably more likely that we'd get = vapor lock upstream from the fuel pump before we stop getting oil from the metering pump.=20 =20 This is just off the top of my head, so, you know, maybe there is = something I overlooked. The question is: what phenomenon was Atkins observing? = He obviously had some reason for his statement. =20 Al ------=_NextPart_000_0001_01C479A6.4F7E5D30 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Subject: [FlyRotary] May not work above 8000 MSL was [FlyRotary] Re: Oil injection, and = more

Dave may be correct, = Perry.

Here is what I think could occur. First, The oil meter pump itself is a positive = displacement pump.

Therefore, from the = standpoint of the pump it will always disperse any oil fed to it into the injectors = and combustion chamber under some amount of pressure. However, the = shaft opening that drives the pump also provides for the oil flow from inside = the Engine Front mount into the metering pump. There is a hole in = the boss of the metering pump shaft (on the inside of the front housing) = that is open to the atmosphere.

At sea level of = course this hole in the boss results in 14.7 psi of pressure on the oil in the meter shaft. So as the positive displacement pump opens a chamber = - the oil flows into the chamber with the help of this 14.7 (or what ever the differential between the pressure in the pump chamber and the = atmosphere- it will something less than 14.7 but probably greater than 12?) and = gets "squirted" toward the injectors = underpressure.

Ed;

I hear what you’re = sayin’, but I really don’t think so. How much pressure does it take = to make hot oil flow through a short length of tube (or a port in the pump) at a = VERY low flow rate? Very little. We’re talking a few = cc/min; and I’d guess even a couple of psi, would do the job nicely. And at 8000 = ft we still have; what, about 11 psi.

As we go to higher altitudes it = is probably more likely that we’d get vapor lock upstream from the = fuel pump before we stop getting oil from the metering pump.

This is just off the top of my = head, so, you know, maybe there is something I overlooked. The question is: = what phenomenon was Atkins observing? He obviously had some reason for = his statement.

Al

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