X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [207.46.163.243] (HELO na01-by2-obe.outbound.protection.outlook.com) by logan.com (CommuniGate Pro SMTP 6.0.8) with ESMTPS id 6749857 for flyrotary@lancaironline.net; Wed, 26 Feb 2014 03:42:27 -0500 Received-SPF: none receiver=logan.com; client-ip=207.46.163.243; envelope-from=SBoese@uwyo.edu Received: from BN1PR05MB105.namprd05.prod.outlook.com (10.255.199.13) by BN1PR05MB390.namprd05.prod.outlook.com (10.141.60.152) with Microsoft SMTP Server (TLS) id 15.0.883.10; Wed, 26 Feb 2014 08:41:49 +0000 Received: from BN1PR05MB105.namprd05.prod.outlook.com ([169.254.11.248]) by BN1PR05MB105.namprd05.prod.outlook.com ([169.254.11.248]) with mapi id 15.00.0883.010; Wed, 26 Feb 2014 08:41:48 +0000 From: "Steven W. Boese" To: Rotary motors in aircraft Subject: RE: [FlyRotary] Re: wastegate control and oil coolers Thread-Topic: [FlyRotary] Re: wastegate control and oil coolers Thread-Index: AQHPMne9G87g9bRyQkKDvyoKID61IZrHHTwG Date: Wed, 26 Feb 2014 08:41:48 +0000 Message-ID: References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [70.196.197.251] x-forefront-prvs: 0134AD334F x-forefront-antispam-report: SFV:NSPM;SFS:(10009001)(6009001)(189002)(199002)(377454003)(81342001)(65816001)(69226001)(66066001)(80022001)(50986001)(79102001)(77982001)(63696002)(47736001)(47976001)(49866001)(90146001)(93136001)(76796001)(56776001)(76786001)(75432001)(56816005)(76576001)(95666003)(4396001)(93516002)(81542001)(77096001)(74706001)(94316002)(54356001)(74876001)(87936001)(53806001)(47446002)(92566001)(86362001)(95416001)(74502001)(94946001)(31966008)(74316001)(74662001)(76482001)(85306002)(51856001)(87266001)(80976001)(74366001)(59766001)(46102001)(85852003)(15975445006)(2656002)(16236675002)(19580395003)(33646001)(54316002)(19580405001)(83322001)(81816001)(81686001)(83072002)(24736002)(80792004);DIR:OUT;SFP:1101;SCL:1;SRVR:BN1PR05MB390;H:BN1PR05MB105.namprd05.prod.outlook.com;CLIP:70.196.197.251;FPR:3C97F6DF.2C3644C1.BBC5BFBF.4AD1D14C.20362;PTR:InfoNoRecords;MX:1;A:1;LANG:en; Content-Type: multipart/alternative; boundary="_000_d153fb1fbc72405285f1c8611ca80172BL2PR05MB098namprd05pro_" MIME-Version: 1.0 X-OriginatorOrg: uwyo.edu --_000_d153fb1fbc72405285f1c8611ca80172BL2PR05MB098namprd05pro_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Bobby, I believe the behavior you are describing would be for an absolute pressure= controller (not variable). The variable absolute pressure controller allows a moving target. The way = the one I have is adjusted, the minimum setting of the variable function is= set at 28" Hg and is referenced to the duct between the compressor and thr= ottle body. The wastegate is closed at pressures less than 28". Advancing= the throttle enables the turbo to eventually develop pressure which is ini= tially limited to 28" Hg upstream of the throttle body by the controller mo= dulating the wastegate. So MAP is controlled by the throttle up to that 28= " Hg. With normal atmospheric pressure here of 23" Hg at 7200 ft elevation= , WOT would only give a MAP of 23" Hg without the turbo. With the throttle= open and MAP at 28" Hg, the variable function of the controller can then b= e actuated with a separate control cable and used to raise the MAP above 28= " Hg. The maximum attainable MAP is determined by the adjustment of the co= ntroller or the capability of the turbo. With my equipment, there is still throttle movement available when 28" Hg i= s reached (the throttle body is larger than necessary) so the throttle body= linkage could be also directly connected to the controller instead of usin= g a separate control cable. That way the single throttle control would ena= ble setting the MAP from idle to the maximum allowed by the controller. I = don't know what the upper limit of MAP is since 36" Hg is the highest setti= ng I've tried. My intent is just to normalize MAP to sea level. With this control mechanism, above 28" Hg the turbo is only producing the a= mount of boost required by the throttle setting rather than producing exces= s boost which is then reduced by throttle body. The result is a minimum of= exhaust back pressure and better efficiency. The absolute pressure reference aneroid in the controller enables the contr= oller to maintain the MAP setting independent of changes in altitude. Steve ________________________________ From: Rotary motors in aircraft on behalf of = Bobby J. Hughes Sent: Tuesday, February 25, 2014 3:18 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: wastegate control and oil coolers Steve I think I understand now. You set the maximum \ target MP and use the throt= tle to operate below the target when desired. Bobby Sent from my iPad --_000_d153fb1fbc72405285f1c8611ca80172BL2PR05MB098namprd05pro_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Bobby,

 

I believe the behavior you are describing would be for an absolute press= ure controller (not variable).

 

The variable absolute pressure controller allows a moving target.  = The way the one I have is adjusted, the minimum setting of the variable fun= ction is set at 28" Hg and is referenced to the duct between the compr= essor and throttle body.  The wastegate is closed at pressures less than 28".  Advancing the throttle = enables the turbo to eventually develop pressure which is initially li= mited to 28" Hg upstream of the throttle body by the controller m= odulating the wastegate.  So MAP is controlled by the throttle up to that 28" Hg.  With normal atmospheric pressure here of 23&= quot; Hg at 7200 ft elevation, WOT would only give a MAP of 23" Hg wit= hout the turbo.  With the throttle open and MAP at 28" Hg, the va= riable function of the controller can then be actuated with a separate control cable and used to raise the MAP above 28" Hg.  = The maximum attainable MAP is determined by the adjustment o= f the controller or the capability of the turbo. 

 

With my equipment, there is still throttle movement available when 28&qu= ot; Hg is reached (the throttle body is larger than necessary) so = ;the throttle body linkage could be also directly connected = to the controller instead of using a separate control cable.  That way the single throttle control would enable setting the MAP from idl= e to the maximum allowed by the controller.  I don't know what the upp= er limit of MAP is since 36" Hg is the highest setting I've tried.&nbs= p; My intent is just to normalize MAP to sea level.

 

With this control mechanism, above 28" Hg the turbo is only pr= oducing the amount of boost required by the throttle setting rather than pr= oducing excess boost which is then reduced by throttle body.  The= result is a minimum of exhaust back pressure and better efficiency.

 

The absolute pressure reference aneroid in the controller enables the co= ntroller to maintain the MAP setting independent of changes in altitude.

 

Steve

     

 

 
 
 
Fro= m: Rotary motors in aircraft <flyrotary@lancaironline.net> on beh= alf of Bobby J. Hughes <bhughes@qnsi.net>
Sent: Tuesday, February 25, 2014 3:18 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: wastegate control and oil coolers
 
Steve

I think I understand now. You set the maximum \ target MP and use the throt= tle to operate below the target when desired. 

Bobby

Sent from my iPad
 
 
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