Return-Path: Received: from [24.25.9.103] (HELO ms-smtp-04-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.2b2) with ESMTP id 3181683 for flyrotary@lancaironline.net; Tue, 20 Apr 2004 21:01:16 -0400 Received: from EDWARD (clt25-78-058.carolina.rr.com [24.25.78.58]) by ms-smtp-04-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id i3L10iC9014752 for ; Tue, 20 Apr 2004 21:00:45 -0400 (EDT) Message-ID: <002501c4273c$13d0ab60$2402a8c0@EDWARD> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Wanted - single stage turbo Date: Tue, 20 Apr 2004 21:00:45 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0022_01C4271A.8C6E0530" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1409 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1409 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0022_01C4271A.8C6E0530 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I'm certainly no expert on turbos but I have turbo charged two = automobiles in my time. My personal opinion is that the Mazda stock = turbo is designed to augment power at low engine rpms on the automobile = (at least the single pre 1993 turbo) to give it that 0-60MPH kick in the = pants. Its my opinion (and that is all it is) that the stock Mazda = turbo would need to have a larger turbine housing (increased A/R ratio) = OR as I have seen done by some of the Aussies some of the housing milled = out around the edge of the turbine blades to provide for exhaust gas = escape. =20 This would move the boost range up and lessen the exhaust back pressure = at the lower rpms as well as reduce heat load and actually provide more = top end power. Also, I question whether Mazda expected their stock = turbo to run at a constant boost for long periods of time. They = probably expected it to boost for considerably less than 30 seconds on = each application (foot in the gas tank), so extend boost for extended = periods could cause problems. Non stock turbos may or may not be suitable depending on their mass flow = rate and turbine A/R housing size. Not trying to discourage anyone from = using the stock Mazda ( I have one sitting in my shop). An external and = larger waste gate can alleviate exhaust gas log jam that to some degree, = I would think. Still its well to consider the limitations or expected = use profile that the engineers may have had in mind. Ed Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC ----- Original Message -----=20 From: David Leonard=20 To: Rotary motors in aircraft=20 Sent: Tuesday, April 20, 2004 2:27 PM Subject: [FlyRotary] Re: Wanted - single stage turbo John, sorry to hear about the busted turbo. You caught my attention. = Since I am in the middle of a rebuild I could think about changing my = set-up. Do you think that the turbo was about to go anyway, or is it = just not the right turbo for our application? Were you running a = wastegate? What MAP were you running when the turbo blew? Rusty's = turbo is the same as yours, do you plan to replace it with an Identical = turbo? Todd and I (and Mecanair and perhaps some others) are also = running that turbo. =20 David Leonard The Rotary Roster: http://members.aol.com/_ht_a/rotaryroster/index.html -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of John Slade Sent: Tuesday, April 20, 2004 10:38 AM To: Rotary motors in aircraft Subject: [FlyRotary] Wanted - single stage turbo Rotarians, Does anyone have a good second gen single stage turbo they want to = sell? Failing that - can someone recommend a good supplier / rebuilder? Yes, you guessed it - I flew for almost an hour this morning, then = fried the turbo. I'd noticed a bit of slack in the bearings, so was = expecting to have to rebuild it anyway - just not quite this soon. The good news is that the failure mode was fairly benign. I was trying = out the turbo at 5000ft and just passing through 170 kts making large = circles over the field. The rpm dropped from about the 4500 I was using = to 3500 and no amount of throttle would increase it from there. Below = 3500 the engine ran almost normally, so I had enough power to climb if = needed. It was maybe a tad rough, but not so's you'd notice. An observer = says I put out a puff of white smoke, and was trailing a small amout of = white smoke as I headed back in for a normal landing. In all I ran the = engine for about 10 minutes after the turbo shaft broke. I lost about 1 = pint of oil and the same of coolant through the collapsed bearings, so = perhaps another 10 minutes or more would have been ok if the field had = been further. The exhaust wheel was floating around in the wastegate = housing, but too large to get through the hole, so all it did was block = the exhaust a bit. I guess this is the "experimental" part of the exercise. :) John Slade Rotary Cozy IV (currently sans turbo) ------=_NextPart_000_0022_01C4271A.8C6E0530 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
I'm certainly no expert on turbos but I = have turbo=20 charged two automobiles in my time.  My personal opinion is that = the Mazda=20 stock turbo is designed to augment power at low engine rpms on the = automobile=20 (at least the single pre 1993 turbo) to give it that 0-60MPH kick in the = pants.  Its my opinion (and that is all it is) that the stock Mazda = turbo=20 would need to have a larger turbine housing (increased A/R ratio) OR as = I have=20 seen done by some of the Aussies some of the housing milled out around = the edge=20 of the turbine blades to provide for exhaust gas escape.  =
 
This would move the boost range up and = lessen the=20 exhaust back pressure at the lower rpms as well as reduce heat load and = actually=20 provide more top end power.  Also, I question whether Mazda = expected their=20 stock turbo to run at a constant boost for long periods of time.  = They=20 probably expected it to boost for considerably less than 30 seconds on = each=20 application (foot in the gas tank), so extend boost for extended periods = could=20 cause problems.
 
Non stock turbos may or may not be = suitable=20 depending on their mass flow rate and turbine A/R housing size.  = Not trying=20 to discourage anyone from using the stock Mazda ( I have one sitting in = my=20 shop). An external and larger waste gate can alleviate exhaust = gas log=20 jam that to some degree, I would think.  Still its well to consider = the=20 limitations or expected use profile that the engineers may have had in=20 mind.
 
Ed
 
 
 
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message -----
From:=20 David=20 Leonard
Sent: Tuesday, April 20, 2004 = 2:27=20 PM
Subject: [FlyRotary] Re: Wanted = - single=20 stage turbo

John, sorry = to hear=20 about the busted turbo.  You caught my attention.  Since I = am in the=20 middle of a rebuild I could think about changing my set-up.  Do = you think=20 that the turbo was about to go anyway, or is it just not the right = turbo for=20 our application?  Were you running a wastegate?  What MAP = were you=20 running when the turbo blew?  Rusty=92s turbo is the same as = yours, do you=20 plan to replace it with an Identical turbo?  Todd and I (and = Mecanair and=20 perhaps some others) are also running that turbo.  =

 

David=20 Leonard

The Rotary=20 Roster:

http://memb= ers.aol.com/_ht_a/rotaryroster/index.html

-----Original=20 Message-----
From: = Rotary=20 motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of John = Slade
Sent: Tuesday, April 20, 2004 = 10:38=20 AM
To: Rotary = motors in=20 aircraft
Subject: = [FlyRotary]=20 Wanted - single stage turbo

 

Rotarians,

Does = anyone have a=20 good second gen single stage turbo they want to = sell?

Failing = that - can=20 someone recommend a good supplier / rebuilder?

 

Yes, you = guessed it=20 - I flew for almost an hour this morning, then fried the turbo. = I'd=20 noticed a bit of slack in the bearings, so was expecting to have to = rebuild it=20 anyway - just not quite this soon.

 

The good = news is=20 that the failure mode was fairly benign. I was trying out the turbo at = 5000ft=20 and just passing through 170 kts making large circles over the = field. =20 The rpm dropped from about the 4500 I was using to 3500 and no amount = of=20 throttle would increase it from there. Below 3500 the engine ran = almost=20 normally, so I had enough power to climb if needed. It was maybe = a tad=20 rough, but not so's you'd notice. An observer says I put out a puff of = white=20 smoke, and was trailing a small amout of white smoke as I headed back = in for a=20 normal landing. In all I ran the engine for about 10 minutes after the = turbo=20 shaft broke. I lost about 1 pint of oil and the same of coolant = through the=20 collapsed bearings, so perhaps another 10 minutes or more would have = been ok=20 if the field had been further.  The exhaust wheel was floating = around in=20 the wastegate housing, but too large to get through the hole, so all = it did=20 was block the exhaust a bit.

 

I guess = this is the=20 "experimental" part of the exercise. :)

John=20 Slade

Rotary = Cozy IV=20 (currently sans=20 turbo)

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