X-Virus-Scanned: clean according to Sophos on Logan.com From: "Steven W. Boese" Received: from [207.46.163.203] (HELO na01-bl2-obe.outbound.protection.outlook.com) by logan.com (CommuniGate Pro SMTP 6.0.9e) with ESMTPS id 6983483 for flyrotary@lancaironline.net; Thu, 17 Jul 2014 15:09:17 -0400 Received-SPF: none receiver=logan.com; client-ip=207.46.163.203; envelope-from=SBoese@uwyo.edu Received: from BL2PR05MB098.namprd05.prod.outlook.com (10.255.232.15) by BL2PR05MB099.namprd05.prod.outlook.com (10.255.232.17) with Microsoft SMTP Server (TLS) id 15.0.990.7; Thu, 17 Jul 2014 19:08:29 +0000 Received: from BL2PR05MB098.namprd05.prod.outlook.com ([169.254.2.78]) by BL2PR05MB098.namprd05.prod.outlook.com ([169.254.2.202]) with mapi id 15.00.0990.007; Thu, 17 Jul 2014 19:08:29 +0000 To: Rotary motors in aircraft Subject: RE: [FlyRotary] power circuit design, was: actual current use by a rotary? Thread-Topic: [FlyRotary] power circuit design, was: actual current use by a rotary? Thread-Index: AQHPoeskhdwFZoQ3aE6O9IEHKW6/iZuknFpM Date: Thu, 17 Jul 2014 19:08:28 +0000 Message-ID: <1405624109480.66518@uwyo.edu> References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [70.196.199.14] x-microsoft-antispam: BCL:0;PCL:0;RULEID: x-forefront-prvs: 027578BB13 x-forefront-antispam-report: SFV:NSPM;SFS:(6009001)(164054003)(189002)(199002)(85664002)(43544003)(377454003)(80022001)(106116001)(4396001)(77982001)(20776003)(31966008)(81342001)(19625215002)(89122001)(76482001)(85852003)(83072002)(110136001)(19627405001)(92726001)(99396002)(92566001)(83322001)(19580405001)(64706001)(19580395003)(99286002)(95666004)(74502001)(101416001)(21056001)(107886001)(105586002)(74662001)(77096002)(87936001)(86362001)(79102001)(107046002)(85306003)(46102001)(81542001)(106356001)(2656002)(66066001)(76176999)(54356999)(36756003)(50986999)(75432001)(88552001)(16236675004)(80792004);DIR:OUT;SFP:;SCL:1;SRVR:BL2PR05MB099;H:BL2PR05MB098.namprd05.prod.outlook.com;FPR:;PTR:InfoNoRecords;MX:1;LANG:en; Content-Type: multipart/alternative; boundary="_000_140562410948066518uwyoedu_" MIME-Version: 1.0 X-OriginatorOrg: uwyo.edu --_000_140562410948066518uwyoedu_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable ________________________________ From: Rotary motors in aircraft on behalf of = Charlie England Sent: Thursday, July 17, 2014 12:14 PM To: Rotary motors in aircraft Subject: [FlyRotary] power circuit design, was: actual current use by a rot= ary? Charlie, I chose to install switch type circuit breakers, one for the primary inject= ors and one for the secondary injectors. I did this because if one injecto= r fails, the backup function requires the corresponding injector of the oth= er rotor to be shut off and then the cold function to be activated. If the= re were a power draw that tripped the breaker, the result would already tak= e care of that first step. The down side is that the cold switch needs to = be used for the backup function instead of being taken care of by the secon= d pole of the recommended DPDT injector switch. This required no additiona= l space on the panel. I did the same thing for the leading and trailing coils but for testing pur= poses rather than risk mitigation. Steve Boese RV6A, 1986 13B NA, RD1A, EC2 Well, time for some followup. My 1st draft for circuit protection looked a lot like what Steve describes = (thanks, Steve), with individual fuses for virtually everything, including = an individual fuse for each injector and each ignition coil. After ruminati= ng over the actual loads for the injectors & coils, I'm having second thoug= hts. The GM coil harness I have in hand has a single DC power wire for all = four coils that it feeds (obviously isn't a part intended for flight, but i= ncluded in Tracy's installation manual). The obvious concern is whether an individual coil or injector failure has a= statistically significant risk of taking out the power supply that's fused= for the total load. If there's no statistically significant danger, weight= & complexity could be reduced by feeding the coils and injectors as groups= . So, is there any consensus on how to handle injector & coil wiring? IIRC, t= here have been some coil failures in flight; were those planes wired with a= single fuse/breaker protecting all the coils, or with individual fuses/bre= akers for each coil? What about the injectors? Any failure modes I'm missing? (other than a dead short on a supply wire, o= f course) Thanks, Charlie --_000_140562410948066518uwyoedu_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

From: Rotary motors in ai= rcraft <flyrotary@lancaironline.net> on behalf of Charlie England <= ;flyrotary@lancaironline.net>
Sent: Thursday, July 17, 2014 12:14 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] power circuit design, was: actual current use b= y a rotary?
 Charlie,
 
I chose to install switch type circuit breakers, one for the primary i= njectors and one for the secondary injectors.  I did this because=  if one injector fails, the backup function requires the corresponding= injector of the other rotor to be shut off and then the cold function to be activated.  If there were a power d= raw that tripped the breaker, the result would already take care of that fi= rst step.  The down side is that the cold switch needs to be used= for the backup function instead of being taken care of by the second pole of the recommended DPDT injector switch.  This = required no additional space on the panel.
 
I did the same thing for the leading and trailing coils but for testin= g purposes rather than risk mitigation.

Steve Boese
RV6A, 1986 13B NA, RD1A, EC2
 
 
 
Well, time for some followup.

My 1st draft for circuit protection looked a lot like what Steve describes = (thanks, Steve), with individual fuses for virtually everything, including = an individual fuse for each injector and each ignition coil. After ruminati= ng over the actual loads for the injectors & coils, I'm having second thoughts. The GM coil harness I h= ave in hand has a single DC power wire for all four coils that it feeds (ob= viously isn't a part intended for flight, but included in Tracy's installat= ion manual).

The obvious concern is whether an individual coil or injector failure has a= statistically significant risk of taking out the power supply that's fused= for the total load. If there's no statistically significant danger, weight= & complexity could be reduced by feeding the coils and injectors as groups.

So, is there any consensus on how to handle injector & coil wiring? IIR= C, there have been some coil failures in flight; were those planes wired wi= th a single fuse/breaker protecting all the coils, or with individual fuses= /breakers for each coil? What about the injectors?

Any failure modes I'm missing? (other than a dead short on a supply wire, o= f course)

Thanks,

Charlie




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