X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [201.225.225.167] (HELO cwpanama.net) by logan.com (CommuniGate Pro SMTP 5.0c2) with ESMTP id 711838 for flyrotary@lancaironline.net; Mon, 05 Sep 2005 13:35:36 -0400 Received-SPF: none receiver=logan.com; client-ip=201.225.225.167; envelope-from=rijakits@cwpanama.net Received: from [201.224.93.110] (HELO usuarioq3efog0) by frontend1.cwpanama.net (CommuniGate Pro SMTP 4.2.10) with SMTP id 48927523 for flyrotary@lancaironline.net; Mon, 05 Sep 2005 12:47:09 -0500 Message-ID: <003601c5b240$01c361c0$6e5de0c9@usuarioq3efog0> From: "rijakits" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Another great flying day = another day of troubleshooting Date: Mon, 5 Sep 2005 12:34:02 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0032_01C5B216.18A10E80" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1437 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 This is a multi-part message in MIME format. ------=_NextPart_000_0032_01C5B216.18A10E80 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Not exactly the same, but running the direstion: During WW II the first fighters didn't run pressurized ignition harnesses. Tales from Gruman state that a couple of test pilots encountered a sudden "Ignition failure" once they reached around 36 K feet. It took (supposedly:)) a coulpe of deadstick landings until one pilot tried to restart the engine on the way down. The others didn't bother - engine is dead because the ignition is dead, why try re-start!! Anyway the man was surprised that the engine started just fine and ran well too. So back up to altitude and on with the test. Wouldn't you know at around 36 K "engine out again, damn!" Finally they caught the problem: The air seems to be a good isolator - once the air got rather thin at altitude, the spark just went right through the wires and grounded. After building a pressurized harness for the whole ignition system - no more problems with "dead ignition" - harnesses. Thomas J. ----- Original Message ----- From: Ed Anderson To: Rotary motors in aircraft Sent: Monday, September 05, 2005 12:06 PM Subject: [FlyRotary] Re: Another great flying day = another day of troubleshooting Well, actually it is absolute pressure that the spark plug is reacting to. In this example, the absolute pressure in the intake is 1.234" HG higher at 10,000 with your 26 " boost than at sea level with your 36" of boost.. This would contribute to an increased pressure in the combustion chamber when it is compressed over the sea level compression pressure. Therefore, the spark plug is facing a tougher task at 10,000 than at Sea level (in this example). Ed ----- Original Message ----- From: David Leonard To: Rotary motors in aircraft Sent: Monday, September 05, 2005 12:57 PM Subject: [FlyRotary] Re: Another great flying day = another day of troubleshooting Actually, Dave you had a higher pressure ratio (manifold to ambient) at 10,000 feet with 26" boost than at sea level with 36". At sea level the pressur e ratio would be 36/29.92 = 1.20. At 10,000 ft ambient pressure = 20.57 " hg , so the pressure ratio would be 26/20.57 = 1.26. Not much greater, but it was higher by approx.1.23" Hg. (1.20 -1.26 = .06 *20.57 = 1.234" Hg). Ed A Right. But what does the plug know about the ambient pressure? I thought that it was just the absolute density of the charge that was contributing to SAG. -- Dave Leonard Turbo Rotary RV-6 N4VY http://members.aol.com/_ht_a/rotaryroster/index.html http://members.aol.com/_ht_a/vp4skydoc/index.html ------=_NextPart_000_0032_01C5B216.18A10E80 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Not exactly the same, but running the=20 direstion:
During WW II the first fighters didn't run = pressurized=20 ignition harnesses.
Tales from Gruman state that a couple of test = pilots=20 encountered a sudden "Ignition failure" once they reached around 36 K=20 feet.
It took (supposedly:)) a coulpe of deadstick = landings=20 until one pilot tried to restart the engine on the way down. The others = didn't=20 bother - engine is dead because the ignition is dead, why try=20 re-start!!
Anyway the man was surprised that the engine = started just=20 fine and ran well too. So back up to altitude and on with the = test.
Wouldn't you know at around 36 K "engine out = again,=20 damn!"
 
Finally they caught the problem: The air seems = to be a=20 good isolator - once the air got rather thin at altitude, the spark just = went=20 right through the wires and grounded. After building a pressurized = harness for=20 the whole ignition system - no more problems with "dead ignition" -=20 harnesses.
 
Thomas J.
----- Original Message -----
From:=20 Ed=20 Anderson
Sent: Monday, September 05, = 2005 12:06=20 PM
Subject: [FlyRotary] Re: = Another great=20 flying day =3D another day of troubleshooting

Well, actually it is absolute pressure that = the spark=20 plug is reacting to.  In this example, the absolute pressure in = the=20 intake is 1.234" HG higher at 10,000 with your 26 " boost than at sea = level=20 with your 36" of boost..  This would contribute to an increased = pressure=20 in the combustion chamber when it is compressed over the sea level = compression=20 pressure.  Therefore, the spark plug is facing a tougher task at = 10,000=20 than at Sea level (in this example).
 
Ed
----- Original Message -----
From:=20 David=20 Leonard
To: Rotary motors in = aircraft=20
Sent: Monday, September 05, = 2005 12:57=20 PM
Subject: [FlyRotary] Re: = Another great=20 flying day =3D another day of troubleshooting

 Actually, Dave you had a higher pressure ratio = (manifold to=20 ambient) at 10,000 feet with 26" boost than at sea level with = 36". =20 At sea level the pressure ratio would be 36/29.92 =3D = 1.20.  At=20 10,000 ft ambient pressure =3D 20.57 " hg , so the pressure=20 ratio would  be 26/20.57 =3D 1.26.  Not = much=20 greater, but it was higher by approx.1.23" Hg. (1.20 -1.26 =3D = .06 *20.57=20 =3D 1.234" Hg).

Ed=20 A

Right.  But what = does the=20 plug know about the ambient pressure?  I thought that it was = just the=20 absolute density of the charge that was contributing to SAG. =

--=20
Dave Leonard
Turbo Rotary RV-6 N4VY
http://memb= ers.aol.com/_ht_a/rotaryroster/index.html
http://members= .aol.com/_ht_a/vp4skydoc/index.html=20
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