X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 16 Dec 2007 16:19:06 -0500 Message-ID: X-Original-Return-Path: Received: from ironport5.liveoakmail.com ([216.110.12.21] verified) by logan.com (CommuniGate Pro SMTP 5.2c1) with ESMTP id 2582701 for lml@lancaironline.net; Sat, 15 Dec 2007 15:55:02 -0500 Received-SPF: none receiver=logan.com; client-ip=216.110.12.21; envelope-from=walter@advancedpilot.com X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Ao8CALfNY0dAMf4VZGdsb2JhbACCOjWNBJgt X-IronPort-AV: E=Sophos;i="4.24,172,1196661600"; d="scan'208,217";a="39729860" Received: from rs5.liveoakhosting.com (HELO secure5.liveoakhosting.com) ([64.49.254.21]) by ironport5.liveoakmail.com with ESMTP; 15 Dec 2007 14:54:23 -0600 Received: (qmail 8632 invoked from network); 15 Dec 2007 14:54:22 -0600 Received: from ip12-197-248-25.networkusa.com (HELO ?10.0.1.4?) (12.197.248.25) by rs5.liveoakhosting.com with (AES128-SHA encrypted) SMTP; 15 Dec 2007 14:54:22 -0600 Mime-Version: 1.0 (Apple Message framework v752.3) In-Reply-To: References: Content-Type: multipart/alternative; boundary=Apple-Mail-3-401528579 X-Original-Message-Id: <5A005728-ACE7-4D2F-B56A-235EDCEC11BD@advancedpilot.com> From: Walter Atkinson Subject: Re: [LML] Re: GAMI Injectors - question for Walter X-Original-Date: Sat, 15 Dec 2007 14:54:20 -0600 X-Original-To: "Lancair Mailing List" X-Mailer: Apple Mail (2.752.3) --Apple-Mail-3-401528579 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed FWIW, I agree 100% with Scott's recommendations. It's sometimes beneficial to remember that the enemy of "very good" is an attempt at "better!" Walter On Dec 15, 2007, at 7:59 AM, Sky2high@aol.com wrote: In a message dated 12/14/2007 3:43:38 P.M. Central Standard Time, douglasbrunner@earthlink.net writes: I have an IO-550N with GAMI injectors and on my first GAMI lean test it appears that the spread between the first and last EGT to peak is about 0.2 gal/hr. In otherwords - pretty darn good. My ram air setup gives about 1.5 inches increase in manifold pressure. I intend to operate LOP at "high" altitudes (high teens mostly) and would like a smooth running engine. Is it the consensus of opinion that using turbo injectors and pressurizing them creates a smoother running engine? Has this been consistently demonstrated? The reason that I ask is that people that I respect have come down on both sides of this issue. Some say that pressurizing the injectors is crucial, others that it makes no difference. At what altitudes and at what settings LOP (20 deg vs 100 deg) do you notice this effect? If you turn off the ram air (but still run LOP) does the engine run more smoothly? Obviously, I can test these issues myself in the future (I am still in Phase 1), but am interested in others experience. Doug, Perhaps you should wait until you, the airplane and the engine are broken in. With the lean test results you have reported, anything you do can only make the spread worse. In other words, evening the air flow to the injectors when such was not the case may create some A/F ratio imbalance leading to roughness. Your results imply that the cylinders are pretty much producing the same power, a useful condition for a smooth running engine. If your primary desire is for smoothness at LOP and you think the engine can be run at low power LOP 'cause it has been tamed, go test 'er now. Let's see, 25 miles is about 125,000 feet, well above your ceiling and still within Phase 1 limitations for distance from the airport. What about the pressure at the injector bleed hole? Well, an awful lot of people have been operating without pressurizing the air - but those have been airplanes not using the benefit of ram air. Continental engines, usually with filtered air taken from the same engine cooling plenum that is supplying air to the injectors, should never see the pressure imbalance. Even with a ram air setup, Continental engines may still not exhibit any problem because the pressure difference is not enough. Forget the consensus - every experimental aircraft engine installation may be different and results may vary. If you think you can improve on your setup by considering the concepts, go experiment and report back. You have an interesting starting condition and the before/after comparison could be educational. If I had your current setup, I wouldn't do a thing for now. Grayhawk, AKA Others See AOL's top rated recipes and easy ways to stay in shape for winter. --Apple-Mail-3-401528579 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1 FWIW, I agree 100% with Scott's recommendations. =A0It's sometimes = beneficial to remember that the enemy of "very good" is an attempt at = "better!" <g>

Walter



On Dec 15, = 2007, at 7:59 AM, Sky2high@aol.com= wrote:

=
In a message dated 12/14/2007 3:43:38 P.M. Central Standard Time, = douglasbrunner@earthlink.net<= /a> writes:
I have an IO-550N with GAMI injectors and on = my first GAMI lean test it appears that the spread=A0 between the = first and last EGT to peak is about 0.2 gal/hr.=A0 In otherwords = -=A0pretty darn=A0good.=A0 My ram air setup gives about 1.5 inches = increase in manifold pressure. I = intend to operate LOP at "high" altitudes (high teens mostly) and = would like a smooth running engine.=A0
=A0
Is it the consensus of opinion that using turbo injectors = and pressurizing them creates a smoother running engine?=A0 Has this = been consistently demonstrated?
=A0
The = reason that I ask is that people that I respect have come down on both = sides of this issue.=A0 Some say that pressurizing the injectors is = crucial, others that it makes no difference.=A0
    =
  • At what altitudes and at what = settings LOP (20 deg vs 100 deg)=A0do you notice this effect? =
  • If you turn off the ram air = (but still run LOP) does the engine run more = smoothly?
Obviously, I can test these issues myself in the future=A0(I = am still in Phase 1), but am interested in others = experience.
=
Doug,
=A0
Perhaps you should wait until you, = the airplane and the engine are broken in.=A0 With the lean test results = you have reported, anything you do can only make=A0the spread=A0worse.=A0 = In other words, evening the air flow to the injectors when such was not = the case may create some A/F ratio imbalance leading to roughness.
=
=A0
Your results imply that the cylinders are pretty = much=A0producing the same power, a useful condition=A0for a smooth = running engine.=A0 If your primary desire is for smoothness at LOP and = you think the engine can be run at=A0low power=A0LOP 'cause it has=A0been = tamed, go test 'er now. Let's see, 25 miles is about 125,000 feet, well = above your ceiling and still within Phase 1 limitations for distance = from the airport.
=A0
What about the pressure at = the injector bleed hole?=A0 Well, an awful lot of people have been = operating without pressurizing the air - but those have been airplanes = not=A0using the benefit of ram air.=A0 Continental engines, usually with = filtered air taken from the same engine cooling plenum that is supplying = air to the injectors, should never see the pressure=A0imbalance.=A0 Even = with a ram air setup, Continental engines may still not=A0exhibit any = problem because the pressure difference is not enough.=A0
=
=A0
Forget the consensus - every experimental aircraft = engine installation may be different and results may vary.=A0 If you = think you can improve on your setup by considering the concepts, go = experiment and report back.=A0 You have an interesting starting = condition and the before/after=A0comparison could be educational.
=
=A0
If I had your current setup, I wouldn't do a thing = for now. =A0
=A0
Grayhawk, AKA = Others




= --Apple-Mail-3-401528579--