X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao102.cox.net ([68.230.241.44] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3831284 for flyrotary@lancaironline.net; Mon, 31 Aug 2009 23:49:01 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.44; envelope-from=rv-4mike@cox.net Received: from fed1rmimpo01.cox.net ([70.169.32.71]) by fed1rmmtao102.cox.net (InterMail vM.8.00.01.00 201-2244-105-20090324) with ESMTP id <20090901034825.KON12000.fed1rmmtao102.cox.net@fed1rmimpo01.cox.net> for ; Mon, 31 Aug 2009 23:48:25 -0400 Received: from wills ([68.105.80.138]) by fed1rmimpo01.cox.net with bizsmtp id bFoP1c00R2z3ATG03FoSrc; Mon, 31 Aug 2009 23:48:26 -0400 X-VR-Score: 0.00 X-Authority-Analysis: v=1.0 c=1 a=O4KcONCDyRsA:10 a=DapaW9-qXb0iihCqq00A:9 a=GWtyslU2d6IlQVQ-DYkA:7 a=FHjtWLHJGZDvNDNPyoNtwZZKERAA:4 a=vIagLfnvWU9Mbq1O:21 a=EvFjtuDEtddnE9lC:21 a=kviXuzpPAAAA:8 a=Ia-xEzejAAAA:8 a=SzKoidEsA2to397hqcIA:9 a=k3ALUz16ymuX_cHO9O0A:7 a=TAKP_cFQnEFAivEQS2YsxZ4lkzAA:4 a=4vB-4DCPJfMA:10 a=EzXvWhQp4_cA:10 a=6DwJrh4WX3J1Tben:21 a=sHF2NVDUa3a33Y43:21 X-CM-Score: 0.00 Message-ID: From: "Mike Wills" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: FW: More Charging Circuit Info Date: Mon, 31 Aug 2009 20:48:23 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_003C_01CA2A7C.61CB86C0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5843 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_003C_01CA2A7C.61CB86C0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Al, That wasnt from me, that was from the weblink Kelly sent. I simply = quoted it. I dont know if it is true or false, but I do know that at = least one of my previous cars opened the alternator field any time the = starter was engaged. It is my understanding that this is typical of car = ignition switches though I dont know if its necessary or just a = holdover. My approach is to leave the field de-energized during cranking, = energize it after the engine starts, and then energize the non-essential = equipment bus. My RV is a very simple day VFR airplane so even when = everything is turned on the electrical load is pretty low. I couldnt be much happier with the cooling. 95 is about as hot as it = ever gets here. Oil temp did not limit my climb performance - I chose to = level at 5000 to avoid conflicts with airliner traffic. At some point I = will investigate the cowl flap option but first just want to get in some = flight time and figure out how to consistently land this thing well. The DNA muffler arrived today. Looks like its actually going to be a = pretty easy swap with my existing muffler so i may get it installed = before the next flight. Mike Wills RV-4 N144MW ----- Original Message -----=20 From: Al Gietzen=20 To: Rotary motors in aircraft=20 Sent: Monday, August 31, 2009 12:18 PM Subject: [FlyRotary] Re: FW: More Charging Circuit Info From Mike - ...ensure that the field is de-energized while cranking = the engine. And I will respectfully disagree with that - at least until somebody = can prove me wrong. The output current is a function of rpm as well as = what the voltage regulator is demanding. From what I can find, I = conclude that alternators typically won't put out their rated current = until they get spinning about 1500 - 2000 rpm, or more (which is usually = about double engine rpm). So there is no risk of damaging the rectifier = diodes at cranking speed. I'm going to guess that it is a worse shock to the electronics if the = field is suddenly turned on at higher rpm when the regulator is on full = demand - although I don't think it's an issue. Off topic, another 1.2 hours closer to completing my Phase 1. = This was the first flight that after I landed I didnt have anything on = my list to fix before the next flight. 95 degrees OAT at takeoff today = and the oil temp got to 200 at the top of the climb to 5000' but backed = off to 192 after I leveled. H2O temp never above 180. Starting to gain = some confidence in it.=20 Contrary to our friend George's faint praiseJ, I'd say your temps = are excellent. If it does that well at OAT of 95 F; then your next = thing will be to think about adjustable cowl flap to reduce cooling drag = at cruise on a cooler day. Al ------=_NextPart_000_003C_01CA2A7C.61CB86C0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Al,
 
 That wasnt from me, that was from = the weblink=20 Kelly sent. I simply quoted it. I dont know if it is true or false, but = I do=20 know that at least one of my previous cars opened the alternator field = any time=20 the starter was engaged. It is my understanding that this is typical of = car=20 ignition switches though I dont know if its necessary or just a=20 holdover.
 
 My approach is to leave the field = de-energized during cranking, energize it after the engine starts, and = then=20 energize the non-essential equipment bus. My RV is a very simple day VFR = airplane so even when everything is turned on the electrical load is = pretty=20 low.
 
 I couldnt be much happier with = the cooling.=20 95 is about as hot as it ever gets here. Oil temp did not limit my climb = performance - I chose to level at 5000 to avoid conflicts with airliner = traffic.=20 At some point I will investigate the cowl flap option but first just = want to get=20 in some flight time and figure out how to consistently land this thing=20 well.
 
The DNA muffler arrived today. Looks = like its=20 actually going to be a pretty easy swap with my existing muffler so i = may get it=20 installed before the next flight.
 
Mike Wills
RV-4 N144MW
----- Original Message -----
From:=20 Al = Gietzen=20
Sent: Monday, August 31, 2009 = 12:18=20 PM
Subject: [FlyRotary] Re: FW: = More=20 Charging Circuit Info

From=20 Mike   - =85..ensure that the field is = de-energized=20 while cranking the engine.

 

And I = will=20 respectfully disagree with that =96 at least until somebody can prove = me wrong.=20  The output current is a function of rpm as well as what the = voltage=20 regulator is demanding.  From what I can find, I conclude that=20 alternators typically won=92t put out their rated current until they = get=20 spinning about 1500 =96 2000 rpm, or more (which is usually about = double engine=20 rpm). So there is no risk of damaging the rectifier diodes at cranking = speed.

 

I=92m = going to guess=20 that it is a worse shock to the electronics if the field is suddenly = turned on=20 at higher rpm when the regulator is on full demand =96 although I = don=92t think=20 it=92s an issue.

 

 Off topic, = another 1.2=20 hours closer to completing my Phase 1. This was the first flight = that=20 after I landed I didnt have anything on my list to fix before the = next=20 flight. 95 degrees OAT at takeoff today and the oil temp got = to 200=20 at the top of the climb to 5000' but backed off to 192 after I = leveled.=20 H2O temp never above 180. Starting to gain some confidence in it.=20

Contrary to our=20 friend George=92s faint praiseJ, = I=92d say your=20 temps are excellent.  If it does that well at = OAT of = 95 F; then=20 your next thing will be to think about adjustable cowl flap to = reduce=20 cooling drag at cruise on a cooler day.

Al

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