X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.123] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3841696 for flyrotary@lancaironline.net; Tue, 08 Sep 2009 17:57:26 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.123; envelope-from=eanderson@carolina.rr.com Received: from computername ([75.191.186.236]) by cdptpa-omta03.mail.rr.com with ESMTP id <20090908215651612.XCZA29089@cdptpa-omta03.mail.rr.com> for ; Tue, 8 Sep 2009 21:56:51 +0000 From: "Ed Anderson" To: "'Rotary motors in aircraft'" Subject: Boost controller or not: [FlyRotary] Re: Regarding Scott Emery's turbo manifold Date: Tue, 8 Sep 2009 17:56:54 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0000_01CA30AD.C0519D10" X-Mailer: Microsoft Office Outlook, Build 11.0.5510 Thread-Index: AcowpvguTjiFQ+7cSuG97afFmHQn/AACxV+A In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 Message-Id: <20090908215651612.XCZA29089@cdptpa-omta03.mail.rr.com> This is a multi-part message in MIME format. ------=_NextPart_000_0000_01CA30AD.C0519D10 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sizing a turbocharger installation by careful selection of a/r (area/radius ratio of the turbine scroll) is certainly a valid way to control your boost as long as you are aware of the limitations and your flight operation regime. Like most things in this hobby it's about compromise. You can have greater simplicity or perhaps less complexity with certain approaches, but you frequently trade off some other feature or benefit. You can fly a turbo without a wastegate or other explicit type of boost control by carefully selecting the a/r size of your turbine housing and/or controlling your engine rpm. However, as mentioned above you will give up some features. First if you use max engine power for take off at sea level then that will create the maximum air mass flow through your installation. IF you size the a/r of your turbo to control boost (instead of using some other type of operated boost controller) then you will need to size it so you don't blow your engine at max power take off at sea level. So that tells you you're a/r is going to have to be considerably larger than a turbo which uses some sort of boost control to prevent boosting beyond your limit. As you increase your altitude, the turbine will need to spend the compressor faster to maintain the same gauge boost - with a large a/r that permits your engine to survive a sea level max power take off - it simply won't be able to have full utilization of the exhaust gas energy to give you as much boost at altitude. Now the advantage of a large a/r (in my opinion) is that instead of getting lots of boost at lower rpm and then having to release exhaust gas through a gate (or some other method of control) at higher rpm to prevent blowing the engine, you make your power and boost at higher engine rpm. So instead of a kick in the seat of the pants on take off, you will simply find you produce more power at altitude and the high end of your rpm range. There are other advantages of a large a/r - one is that there is less obstruction to exhaust flow when you are not under boost, there is less exhaust back pressure because the flow is less restricted and of course it can be lighter without a wastegate. So it is certainly possible, but you are going to have to experimental determine what size a/r turbine housing will do the job for you. So I would buy my turbo from a company which would allow me to exchange the turbine housing (for different a/r) either free of charge or a modest exchange fee - because unless somebody has already done this, you will probably have to try two or three different a/r turbine housings to get the correct one. However, you indicated you wanted great short field performance on take off and similar performance at 18,000 feet - I just don't believe you are going to find any single a/r that will fit those conditions. You can choose one or the other and get what you want, but it doubtful you'll get what you want at both ends of the spectrum without some sort of boost controller. I have no experience turbocharging aircraft although I have studied it quite a bit - but, I have scratch build turbocharger systems for cars. Good luck on your decision. Ed Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://www.dmack.net/mazda/index.html http://www.flyrotary.com/ http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.rotaryaviation.com/Rotorhead%20Truth.htm _____ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of shipchief@aol.com Sent: Tuesday, September 08, 2009 1:07 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Regarding Scott Emery's turbo manifold Bob; I understand your position, please understand mine; I don't want anything near 'maximum boost'. I'm willing to limit the turbochargers ability to make boost, by installing a turbine housing that is open enough to be in a perpetual bypass mode. I'm looking for a very modest increase in power, so I do not want a highly stressed turbine. I don't have an instrument rating, so I won't be flying much above 18,000 ft. Van designed the RV-8 airframe for 200 HP, and Tracy rated my gearbox at 200 HP as well. I am working toward a ballanced aircraft where all the systems meet the same performance point, which is flight in the 120 to 222 MPH range. I fly in Washington, with regular flights over the Cascade mountain range, and over water to the San Juan Islands. I seek good short field performance, and a substantial climb rate. After that I seek a strong cruise for 1 to 2 hours in the 7,000 to 12,000 ft zone followed by rapid decent without regard to shock cooling. I'm not sure about this following point, but I am hoping to be able to lean out at cruise with open throttle to control turbo boost. It depends on many ballanced factors, but turbos are controlled by heat input. A bypass literally bypasses a portion of the engine exhaust heat around the turbine. The rotary engine's ability to run lean of peak has a potential application here. Finally, I do have a plan for a waste gate if it turns out I need one. I'm just not willing to add stuff to my plane until I have a demonstrated need for it. If that occurs, I'll post my findings and you will be vindicated. -----Original Message----- From: Rogers, Bob J. To: Rotary motors in aircraft Sent: Tue, Sep 8, 2009 9:14 am Subject: [FlyRotary] Re: Regarding Scott Emery's turbo manifold I recommend that you get the book Maximum Boost by Corky Bell if you want to know all about turbochargers, including wastegates. See http://search.barnesandnoble.com/Maximum-Boost/Corky-Bell/e/9780837601601 You really need a wastegate and it is external to the TO4. The wastegate should be mounted in the exhaust manifold before the flow gets to the turbo. It controls the exhaust pressure and, when necessary, allows exhaust to bypass the turbo to control the amount of boost. The pop-off valve is on the intake side and serves primarily to protect from over pressuring the system when you rapidly close the throttle. This should not happen in an airplane, but it does not hurt to have one (other than extra cost and slight extra weight). Bob _____ From: Rotary motors in aircraft [ mailto:flyrotary@lancaironline.net] On Behalf Of Chris Barber Sent: Sunday, September 06, 2009 8:06 PM To: Rotary motors in aircraft Subject: [FlyRotary] Regarding Scott Emery's turbo manifold Scott/Group, I was just looking at the turbo set up that you posted. http://gallery.eaa326.org/members/semery/?g2_page=1 Thanks for posting. It looks great. It is continuing my motivation to pursue the turbo. I also have the Conversions Concepts mount. I too will likely have to fabricate - read that as have fabricated since, contrary to my manly man status :-), I know not how to weld :-( - my turbo manifold. I like how clean and simple yours is. I am trying to decide the best position for it. The current extension that I have on my engine - in order to clear the Mistral Injectors location puts my aftermarket turbo manifold perilously close to my aileron control linkage (about 3/4 of an inch, or so). Also, it is right up on the top of the cowling. My question to you is, I did not notice a waste gate mounting place on your turbo exhaust manifold. Both my aftermarket manifolds have a place to mount a waste gate. Did I miss it, is the wastage internal to the turbo? which I think is how Mazda did it, but figured this was not the case with the larger T04's we seem to be using). Where might I add one to a manifold I would have made. Would the position be secondary to just putting it in the place with most clearance? While I have learned a great deal about how turbo's work, I am far from versed enough yet. Is there a conventional wisdom as to when to use a waste gate. I thought they were standard and the primary means to control boost, along with a pop off valve (if that is the correct term and idea?) Advice and insight is sought and appreciated. Thanks in advance guys and gals. All the best, Chris Cpl. Christopher Barber, JD Badge 330 Bellaire Police Department 5110 Jessamine Bellaire, Texas 77401 713-668-0487 713-662-8289 fax CBarber@BellairePolice.com Warning: This e-mail transmission, and any documents, files or previous e-mails attached to it, may contain confidential information that is legally privileged. If you are not the intended recipient or the person responsible for delivering it to the intended recipient, you are hereby notified that any disclosure, copying, distribution or use of any of the information contained in or attached to this transmission is STRICTLY PROHIBITED. If you have received this transmission in error, please immediately notify us by telephone at 713-662-8132 and destroy the original transmission and its attachments without reading them. Thank you. ------=_NextPart_000_0000_01CA30AD.C0519D10 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Sizing a turbocharger installation = by careful selection of a/r (area/radius ratio of the turbine scroll) is = certainly a valid way to control your boost as long as you are aware of the = limitations and your flight operation regime.

 

Like most things in this hobby = it’s about compromise.  You can have greater simplicity or perhaps less complexity with certain approaches, but you frequently trade off some = other feature or benefit. 

 

You can fly a turbo without a = wastegate or other explicit type of boost control by carefully selecting the a/r size = of your turbine housing and/or controlling your engine rpm.  However, = as mentioned above you will give up some features.  =

 

First if you use max engine power = for take off at sea level then that will create the maximum air mass flow through = your installation.  IF you size the a/r of your turbo to control boost = (instead of using some other type of operated boost controller)  then you = will need to size it so you don’t blow your engine at max power take off at = sea level.  So that tells you you’re a/r is going to have to be considerably larger than a turbo which uses some sort of boost control = to prevent boosting beyond your limit.  As you increase your altitude, = the turbine will need to spend the compressor faster to maintain the same = gauge boost – with a large a/r that permits your engine to survive a sea = level max power take off  - it simply won’t be able to have full = utilization of the exhaust gas energy  to give you as much boost at = altitude.    

 

 

 Now the advantage of a large = a/r (in my opinion) is that instead of getting lots of boost at lower rpm and = then having to release exhaust gas through a gate (or some other method of = control) at higher rpm to prevent blowing the engine, you make your power and = boost at higher engine rpm.  So instead of a kick in the seat of the pants = on take off, you will simply find you produce more power at altitude and the = high end of your rpm range.

 

 

There are other advantages of a = large a/r – one is that there is less obstruction to exhaust flow when you = are not under boost, there is less exhaust back pressure because the flow is = less restricted and of course it can be lighter without a = wastegate.

 

So it is certainly possible, but = you are going to have to experimental determine what size a/r turbine housing = will do the job for you.  So I would buy my turbo from a company which = would allow me to exchange the turbine housing (for different a/r) either free of = charge or a modest exchange fee – because unless somebody has already done = this, you will probably have to try two or three different a/r turbine = housings to get the correct one.

 

 

However, you indicated you wanted = great short field performance on take off and similar performance at 18,000 = feet – I just don’t believe you are going to find any single a/r that = will fit those conditions.  You can choose one or the other and get what you = want, but it doubtful you’ll get what you want at both ends of the = spectrum without some sort of boost controller.

 

I have no experience turbocharging aircraft although I have studied it quite a bit – but, I have = scratch build turbocharger systems for cars. 

 

Good luck on your = decision.

 

Ed

 

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of shipchief@aol.com
Sent: Tuesday, September = 08, 2009 1:07 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: = Regarding Scott Emery's turbo manifold

 

Bob;

I understand your position, please understand = mine;

I don't want anything near 'maximum boost'. I'm willing to limit = the turbochargers ability to make boost, by installing a turbine housing = that is open enough to be in a perpetual bypass mode. I'm looking for a very = modest increase in power, so I do not want a highly stressed turbine. I don't = have an instrument rating, so I won't be flying much above 18,000 ft. Van = designed the RV-8 airframe for 200 HP, and Tracy rated my gearbox at 200 HP as well. I am working toward a ballanced = aircraft where all the systems meet the same performance point, which is flight = in the 120 to 222 MPH range. I fly in Washington, with regular flights over the Cascade mountain range, and over water to = the San Juan Islands. I seek good short field performance, and a substantial climb rate. After = that I seek a strong cruise for 1 to 2 hours in the 7,000 to 12,000 ft zone = followed by rapid decent without regard to shock cooling. =

I'm not sure about this following point, but I am hoping to be = able to lean out at cruise with open throttle to control turbo boost. It depends = on many ballanced factors, but turbos are controlled by heat input. A = bypass literally bypasses a portion of the engine exhaust heat around the = turbine. The rotary engine's ability to run lean of peak has a potential application = here.

Finally, I do = have a plan for a waste gate if it turns out I need one. I'm just not willing to add = stuff to my plane until I have a demonstrated need for it. If that occurs, = I'll post my findings and you will be vindicated.

-----Original Message-----
From: Rogers, Bob J. <BRogers@FDIC.gov>
To: Rotary motors in = aircraft <flyrotary@lancaironline.net>
Sent: Tue, Sep 8, 2009 9:14 am
Subject: [FlyRotary] Re: Regarding Scott Emery's turbo = manifold

I recommend that you get the book = Maximum Boost by Corky Bell if you want to know all about turbochargers, = including wastegates. 

 

You really need a wastegate and it = is external to the TO4. The wastegate should be mounted in the exhaust = manifold before the flow gets to the turbo.  It controls the exhaust = pressure and, when necessary, allows exhaust to bypass the turbo to control the amount = of boost. The pop-off valve is on the intake side and serves primarily to = protect from over pressuring the system when you rapidly close the = throttle.  This should not happen in an airplane, but it does not hurt to have one = (other than extra cost and slight extra weight).

 

Bob

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net= ] On Behalf Of Chris Barber
Sent: Sunday, September = 06, 2009 8:06 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] = Regarding Scott Emery's turbo manifold

 

Scott/Group,

 

I was just looking at the turbo set up that you posted.  http://gallery.eaa326.org/members/semery/?g2_page=3D= 1  Thanks for posting.

 

It looks great.  It is continuing my motivation = to pursue the turbo. I also have the Conversions Concepts mount. =  I too will likely have to fabricate - read that as have fabricated since, contrary to my manly man status :-), I know not how to weld = :-(   - my turbo manifold.  I like how clean and simple yours = is.

 

I am trying to decide the best position for it.  = The current extension that I have on my engine - in order to clear the = Mistral Injectors location puts my aftermarket turbo manifold perilously close = to my aileron control linkage (about 3/4 of an inch, or so).  Also, it is = right up on the top of the cowling.

 

My question to you is, I did not notice a waste gate mounting place on your turbo exhaust manifold.  Both my = aftermarket manifolds have a place to mount a waste gate.  Did I miss it, is = the wastage internal to the turbo? which I think is how Mazda did it, but = figured this was not the case with the larger T04's we seem to be using).  = Where might I add one to a manifold I would have made.  Would the = position be secondary to just putting it in the place with most = clearance?

 

While I have learned a great deal about how turbo's = work, I am far from versed enough yet.  Is there a conventional wisdom as = to when to use a waste gate.  I thought they were standard and the primary = means to control boost, along with a pop off valve (if that is the correct = term and idea?)

 

Advice and insight is sought and = appreciated.

 

Thanks in advance guys and = gals.

 

All the best,

 

Chris

 

Cpl. Christopher Barber, = JD

Badge 330

Bellaire Police = Department

5110 Jessamine

Bellaire, Texas 77401

 

713-668-0487

713-662-8289 fax

 


Warning: This e-mail transmission, and any documents, files or previous = e-mails attached to it, may contain confidential information that is legally privileged. If you are not the intended recipient or the person = responsible for delivering it to the intended recipient, you are hereby notified that = any disclosure, copying, distribution or use of any of the information = contained in or attached to this transmission is STRICTLY PROHIBITED. If you have = received this transmission in error, please immediately notify us by telephone at 713-662-8132 and destroy the original transmission and its attachments = without reading them. Thank you.

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