Return-Path: <13brv3@bellsouth.net> Received: from imf19aec.mail.bellsouth.net ([205.152.59.67] verified) by logan.com (CommuniGate Pro SMTP 4.1.3) with ESMTP id 2574920 for flyrotary@lancaironline.net; Wed, 10 Sep 2003 12:25:23 -0400 Received: from rad ([68.212.14.21]) by imf19aec.mail.bellsouth.net (InterMail vM.5.01.05.27 201-253-122-126-127-20021220) with ESMTP id <20030910162523.GIDY24929.imf19aec.mail.bellsouth.net@rad> for ; Wed, 10 Sep 2003 12:25:23 -0400 From: "Russell Duffy" <13brv3@bellsouth.net> To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: turbo wastegate requirements Date: Wed, 10 Sep 2003 11:25:22 -0500 Message-ID: <002901c377b8$22387900$0201a8c0@rad> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_002A_01C3778E.39627100" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.4510 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 Importance: Normal In-Reply-To: This is a multi-part message in MIME format. ------=_NextPart_000_002A_01C3778E.39627100 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable On my 91 turbo there is a vacuum pipe which comes out of the waste gate = and goes to the side of the turbo casing. It has a T for another vacuum hose connection which goes to a solenoid in the stock installation. The = engine guy tells me that if this vacuum hose is open to the ambiant pressure, = then the wastegate will be open. If it's blocked, then the wastegate will = close. All I have to do to control the wastegate is fit a valve to this hose.=20 =20 I think your engine guy has it exactly backwards, or he turn it around knowing you're a canard guy :-) =20 =20 Assuming this is a hose that goes from the wastegate actuator (big = vacuum pot looking thing) to the compressor side of the turbo, it's using = pressure to open the wastegate. If it's blocked, the wastegate opens at the actuator's normal spring pressure. If you leave it open, the wastegate stays shut, and pieces of apex seals start departing the engine :-0 =20 You are correct about the possibility of having a valve in the cockpit = to control the boost. As I mentioned in the long-winded post a minute ago, = you can use a simple needle valve to set the boost pressure. There's no = reason this can't be in the cockpit, and set as needed for cruise flight. =20 =20 I wonder what Rusty and Todd are doing in this area. =20 As I mentioned, I'm working with manual control only at this point. The reason is that I have 9.7 rotors, and don't want to run over about 36" = of MAP, which is 3 psi of boost at sea level. When you use a wastegate actuator, the minimum boost is set by the spring in the unit, and I've = never seen an actuator with a spring less than about 5 psi. I am considering modifying an actuator at some point, but that's down the line a bit. = Gotta get a real oil cooler first. =20 =20 Cheers, Rusty =20 ------=_NextPart_000_002A_01C3778E.39627100 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable Message
On my 91 turbo=20 there is a vacuum pipe which comes out of the waste gate and goes to=20 the side of the turbo casing. It has a T for another vacuum hose = connection=20 which goes to a solenoid in the stock installation. The engine guy tells = me that=20 if this vacuum hose is open to the ambiant pressure, then the wastegate = will be=20 open. If it's blocked, then the wastegate will close. All I have to do = to=20 control the wastegate is fit a valve to this hose. 
 
I think your = engine guy has=20 it exactly backwards, or he turn it around knowing you're a canard guy = :-) =20
 
Assuming = this is a hose=20 that goes from the wastegate actuator (big vacuum pot looking = thing) to the=20 compressor side of the turbo, it's using pressure to open the=20 wastegate.  If it's blocked, the wastegate opens at the actuator's = normal=20 spring pressure.  If you leave it open, the wastegate stays shut, = and=20 pieces of apex seals start departing the engine=20 :-0
 
You are = correct about the=20 possibility of having a valve in the cockpit to control the boost.  = As I=20 mentioned in the long-winded post a minute ago, you can use a simple = needle=20 valve to set the boost pressure.  There's no reason this can't be = in the=20 cockpit, and set as needed for cruise flight. =20   
 
I = wonder what Rusty=20 and Todd are doing in this area.
 
As I mentioned, I'm working with manual = control only at=20 this point.  The reason is that I have 9.7 rotors, and don't want = to run=20 over about 36" of MAP, which is 3 psi of boost at sea level.  When = you use=20 a wastegate actuator, the minimum boost is set by the spring in the = unit, and=20 I've never seen an actuator with a spring less than about 5 psi.  I = am=20 considering modifying an actuator at some point, but that's down the = line a=20 bit.  Gotta get a real oil cooler first.  =
 
Cheers,
Rusty
 
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