X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 17 Dec 2007 19:28:03 -0500 Message-ID: X-Original-Return-Path: Received: from mta13.adelphia.net ([68.168.78.44] verified) by logan.com (CommuniGate Pro SMTP 5.2c1) with ESMTP id 2601894 for lml@lancaironline.net; Mon, 17 Dec 2007 08:52:07 -0500 Received-SPF: pass receiver=logan.com; client-ip=68.168.78.44; envelope-from=glcasey@adelphia.net Received: from [75.82.212.14] by mta13.adelphia.net (InterMail vM.6.01.05.02 201-2131-123-102-20050715) with ESMTP id <20071217135126.QALR7470.mta13.adelphia.net@[75.82.212.14]> for ; Mon, 17 Dec 2007 08:51:26 -0500 Mime-Version: 1.0 (Apple Message framework v752.2) In-Reply-To: References: Content-Type: multipart/alternative; boundary=Apple-Mail-84-548952520 X-Original-Message-Id: <2E4A217E-05BA-424F-920D-374964BA7719@adelphia.net> From: Gary Casey Subject: Re: GAMI Injectors - question for Walter X-Original-Date: Mon, 17 Dec 2007 05:51:24 -0800 X-Original-To: "Lancair Mailing List" X-Mailer: Apple Mail (2.752.2) --Apple-Mail-84-548952520 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Using the vacuum pump (for those of us that still have one, who seem to be in the minority nowadays) is an interesting idea. I'm not sure I would put the extra load on one that was used for the primary attitude information on an IFR plane, but in my case the vacuum system is the backup. I would think that the pump would produce plenty of air, but I don't have displacement or flow information to back that up. I think the bleed holes are bigger than .025 as the fuel orifices, as I recall are about that size. I'm thinking they are more like .030 to .040. I'd want another check valve to handle the air flow when idling as that is when the air flow is the highest and the vacuum pump is producing the least. I'd probably set it up to deliver something less than the optimum 3 inches as that would almost double the pressure the pump has to deliver. No sense in working it too hard, as pilots of P210s found out the hard way. All I need to come up with is a lightweight, simple relief/check valve and manifold. And I'm not sure this will work on Continental fuel systems as I don't know what effect back pressure will have on fuel flow calibrations at idle. The Lycoming systems are mostly insensitive to this. Gary Casey > > So, the question is, "How to boost that air pressure at higher > altitudes?" > Do we need a pressure regulator if over boosting the pressure > causes no improvement or harm? > What about using the filtered output from an existing vacuum pump > (with a relief valve, of course)? > If you have an all electric airplane, then just using a spare > vacuum pump to assist the injection air might be, uh, interesting. > If there is an Electronic Ignition, how about using the magneto > drive to operate a pump. > How about a small dc electric pump (aquarium?)? > What about warming the air to cause expansion? > > After all, I know there are engineers that could carry these simple > calculations further: > Suppose the bleed holes are .025 in diameter. Suppose there are 6 > of them. What CFM requirement is there for an air pump to maintain > 1.5+ PSI thru ports with an area totaling .003 square inches? > Maybe a diaphragm aquarium pump would work.... Hmmmmmm........ > > Example: http://www.fishfarmsupply.ca/lowcost_12v_pump.htm > > Scott AKA Grayhawk --Apple-Mail-84-548952520 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1 Using the vacuum pump (for those of us=A0that still have one, who=A0seem = to be in the minority nowadays) is an interesting idea. =A0I'm not sure = I would put the extra load on one that was used for the primary attitude = information on an IFR plane, but in my case the vacuum system is the = backup. =A0I would think that the pump would produce plenty of air, but = I don't have displacement or flow information to back that up. =A0I = think the bleed holes are bigger than .025 as the fuel orifices, as I = recall are about that size. =A0I'm thinking they are more like .030 to = .040. =A0I'd want another check valve to handle the air flow when idling = as that is when the air flow is the highest and the vacuum pump is = producing the least. =A0I'd probably set it up to deliver something less = than the optimum 3 inches as that would almost double the pressure the = pump has to deliver. =A0No sense in working it too hard, as pilots of = P210s found out the hard way. =A0All I need to come up with is a = lightweight, simple relief/check valve and manifold. =A0And I'm not sure = this will work on Continental fuel systems as I don't know what effect = back pressure will have on fuel flow calibrations at idle. =A0The = Lycoming systems are mostly insensitive to this.
Gary = Casey

=
So, the question is, "How=A0to boost that air pressure at higher = altitudes?"
Do we need a pressure regulator if over boosting = the pressure causes no improvement or harm?=A0
What about = using the filtered output from=A0an existing=A0vacuum pump (with a = relief valve, of course)?
If you have an all electric = airplane, then just using=A0a spare=A0vacuum pump to assist the = injection air might be, uh, interesting.
If there is an = Electronic Ignition, how about using=A0the magneto drive to operate a = pump.
How about a small dc electric pump (aquarium?)?
=
What about warming the air to cause expansion?
=A0
=
After all, I know there are engineers that could carry these simple = calculations further:
Suppose the bleed holes are .025 in = diameter.=A0 Suppose there are 6 of them.=A0 What CFM requirement is = there for an air=A0pump to maintain 1.5+ PSI thru ports with an = area=A0totaling .003 square inches?=A0 Maybe a diaphragm aquarium pump = would work.... Hmmmmmm........
=A0
=A0
Scott = AKA Grayhawk

= --Apple-Mail-84-548952520--