X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [24.25.9.100] (HELO ms-smtp-01-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 5.0c2) with ESMTP id 712318 for flyrotary@lancaironline.net; Mon, 05 Sep 2005 22:14:45 -0400 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.100; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-065-188-083-049.carolina.res.rr.com [65.188.83.49]) by ms-smtp-01-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id j862DwWf029485 for ; Mon, 5 Sep 2005 22:13:59 -0400 (EDT) Message-ID: <001501c5b288$63228430$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Another great flying day = another day of troubleshooting Date: Mon, 5 Sep 2005 22:12:09 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0012_01C5B266.DBD561D0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0012_01C5B266.DBD561D0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To prevent oxidation of the filament - quickly burns out when exposed to = atmosphere (oxygen). =20 Ed ----- Original Message -----=20 From: Finn Lassen=20 To: Rotary motors in aircraft=20 Sent: Monday, September 05, 2005 10:02 PM Subject: [FlyRotary] Re: Another great flying day =3D another day of = troubleshooting Hmm... and here I thought that vacumn was a better insulator than air = ... Why is the air pumped out of lightbulbs? Finn rijakits wrote: 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 -----=20 From: Ed Anderson=20 To: Rotary motors in aircraft=20 Sent: Monday, September 05, 2005 12:06 PM Subject: [FlyRotary] Re: Another great flying day =3D 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 -----=20 From: David Leonard=20 To: Rotary motors in aircraft=20 Sent: Monday, September 05, 2005 12:57 PM Subject: [FlyRotary] Re: Another great flying day =3D 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 pressure ratio would be 36/29.92 =3D 1.20. At 10,000 ft = ambient pressure =3D 20.57 " hg , so the pressure ratio would be = 26/20.57 =3D 1.26. Not much greater, but it was higher by approx.1.23" = Hg. (1.20 -1.26 =3D .06 *20.57 =3D 1.234" Hg).=20 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.=20 --=20 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_0012_01C5B266.DBD561D0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
To prevent oxidation of the filament - quickly = burns out=20 when exposed to atmosphere (oxygen). 
 
Ed
----- Original Message -----
From:=20 Finn=20 Lassen
Sent: Monday, September 05, = 2005 10:02=20 PM
Subject: [FlyRotary] Re: = Another great=20 flying day =3D another day of troubleshooting

Hmm... and here I thought that vacumn was a better = insulator=20 than air ...
Why is the air pumped out of=20 lightbulbs?

Finn

rijakits wrote:
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=20 didn't bother - engine is dead because the ignition is dead, why try = re-start!!
Anyway the man was surprised that the engine = started=20 just fine and ran well too. So back up to altitude and on with the=20 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=20 went right through the wires and grounded. After building a = pressurized=20 harness for the whole ignition system - no more problems with "dead=20 ignition" - harnesses.
 
Thomas J.
-----=20 Original Message ----- From:=20 Ed Anderson To:=20 Rotary motors in = aircraft=20 Sent:=20 Monday, September 05, 2005 12:06 PM Subject:=20 [FlyRotary] Re: Another great flying day =3D another day of=20 troubleshooting

Well, actually it is absolute pressure = that the=20 spark plug is reacting to.  In this example, the absolute = pressure in=20 the intake is 1.234" HG higher at 10,000 with your 26 " boost than = at sea=20 level with your 36" of boost..  This would contribute to an = increased=20 pressure in the combustion chamber when it is compressed over the = sea=20 level compression pressure.  Therefore, the spark plug is = facing a=20 tougher task at 10,000 than at Sea level (in this = example).
 
Ed
-----=20 Original Message ----- From:=20 David=20 Leonard To:=20 Rotary motors in = aircraft=20 Sent:=20 Monday, September 05, 2005 12:57 PM Subject:=20 [FlyRotary] Re: Another great flying day =3D another day of=20 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=20 36".  At sea level the pressure ratio would be 36/29.92 = =3D=20 1.20.  At 10,000 ft ambient pressure =3D 20.57 " hg , = so the=20 pressure ratio would  be 26/20.57 =3D = 1.26. =20 Not much greater, but it was higher by approx.1.23" Hg. = (1.20 -1.26=20 =3D .06 *20.57 =3D 1.234" Hg).

Ed=20 A

Right.  But = what does=20 the plug know about the ambient pressure?  I thought that = it was=20 just the 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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