X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from securemail.ever-tek.com ([64.129.170.194] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3885043 for flyrotary@lancaironline.net; Tue, 13 Oct 2009 19:49:24 -0400 Received-SPF: none receiver=logan.com; client-ip=64.129.170.194; envelope-from=cbarber@bellairepolice.com Return-Path: cbarber@bellairepolice.com Received: from fcd-mail05.FCDATA.PRIVATE ([172.16.5.24]) by FCD-MAIL03.FCDATA.PRIVATE with Microsoft SMTPSVC(6.0.3790.3959); Tue, 13 Oct 2009 18:49:04 -0500 Received: from fcd-mail05.FCDATA.PRIVATE ([4.4.5.9]) byfcd-mail05.FCDATA.PRIVATE ([4.4.5.9]) with mapi; Tue, 13 Oct 2009 18:48:45-0500 Message-ID: Date: Tue, 13 Oct 2009 18:48:45 -0500 From: Chris Barber Subject: RE: [FlyRotary] Re: intake manifold 13b 86 To: Rotary motors in aircraft Thread-Topic: [FlyRotary] Re: intake manifold 13b 86 Thread-Index: AcpMRsudW6Rj/MPlQWWMjxFkzq345gAF+VAE References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US X-OriginalArrivalTime: 13 Oct 2009 23:49:04.0760 (UTC) FILETIME=[BF3E0F80:01CA4C5F] MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="_000_D0F749463E0EF646B3946A4248B3C86A020D4135F4fcdmail05FCDA_" This is a multi-part message in MIME format. --_000_D0F749463E0EF646B3946A4248B3C86A020D4135F4fcdmail05FCDA_ Content-Type: text/plain;charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable George, I do not believe stagging is based on RPM but instead Manifold Pressure (= MP). By default, IIRC, Tracy has it at 15.5. Should that conflict to a = cruise or often used setting, such as on final, it is pretty easily chang= ed by selecting....I think, Mode 7, increasing the throttle to the desire= d MP and then pressing the Program button when at the desired MP/RPM. Th= at will set it to that chosen MP/RPM. FWIW. All the best, Chris Barber Houston Cpl Christopher Barber, JD. Badge 330 Bellaire Police Department 5100 Jessamine Bellaire, Texas 77401 713-668-0487 CBarber@BellariePolice.com ________________________________ From: Rotary motors in aircraft [flyrotary@lancaironline.net] On Behalf O= f George Lendich [lendich@aanet.com.au] Sent: Tuesday, October 13, 2009 3:48 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: intake manifold 13b 86 Lynn, About what RPM does the secondaries come in, if I go by memory, which isn= 't always the best thing for mew to do, It's about 3500 rpm - does that s= ound right? George (down under) That would be like disabling one of the intake valves in a 4 valve per cy= linder piston engine. Yes it will still run but the power would be down s= omewhat. Just not a good idea. Tracy On Mon, Oct 12, 2009 at 4:24 PM, jrhopkins > wrote: has anyone used blocked off the center two apertures and used the front a= nd rear intake manifolds only? i do not understand the need for the cent= er split intake for aircraft use. thanks Richard The center ports are smaller (the primary ports in the center iron) are p= art of a system designed to use a carburetter. That means that high veloc= ity was needed to keep the energy high and the fuel air mixture from form= ing droplets and adding to HC. So the smaller barrels of the 4 barrel carb open first to operate the eng= ine on the high velocity runners to those ports. Most of the time the en= gine ran only on those ports. So the effect is that the carb looks small = and the fuel mileage is fair, and HC (unburned Hydrocarbons) are within r= equirements. The key is velocity. The smaller the tube per cubic foot of mixture per s= econd, the higher the velocity. So the center ports and runners are small= =2E Since only about 20 HP is needed to go 60 MPH, most of the engines li= fe is run out on the small ports. When more power is demanded, low manifold pressure opens the secondaries = in the carb via a vacuum diaphragm and the big ports in the front and rea= r irons are called into use. The fuel economy idea is out the window and = in a properly tuned car the engine RPM will be high enough to provide fai= r velocity in the big runners and ports. So the engine will accelerate to= the best power RPM (red line) to deliver the engines rated HP. In the fuel injected engine this feature is still in use so you see the t= hrottle bodies multiple inlets. Same idea. In aircraft use, there is little use for 20 HP beyond a slow taxi. Take o= ff power would be everything you can come up with HP wise. So all 4 ports= and runners are needed. Once in flight, close to 50 HP would be needed j= ust to maintain level slow flight, so there is just no application where = the plane would fly on just the center ports. As the plane climbs the ava= ilable HP goes down based on air density changes, so in most cases, the throttle is left at wide open or very close to that= =2E Further power reduction is by leaning to maintain the ideal fuel air = mixture, or even leaning further to well over lean, or Lean Of Peak. That is Lean Of Peak EGT (the rotary does that very well), So power goes = down as well as fuel consumption and EGT. The throttle will be left wide = open. Closing off the center ports would be the same as not opening the throttl= e by some amount. If you want to build in more power, the 84-85 12A has the biggest runners= and ports in the center iron. Lynn E. Hanover Warning: This e-mail transmission, and any documents, files or previous e= -mails attached to it, may contain confidential information that is legal= ly privileged. If you are not the intended recipient or the person respon= sible for delivering it to the intended recipient, you are hereby notifie= d that any disclosure, copying, distribution or use of any of the informa= tion contained in or attached to this transmission is STRICTLY PROHIBITED= =2E If you have received this transmission in error, please immediately n= otify us by telephone at 713-662-8132 and destroy the original transmissi= on and its attachments without reading them. Thank you. --_000_D0F749463E0EF646B3946A4248B3C86A020D4135F4fcdmail05FCDA_ Content-Type: text/html;charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Georg= e,
 
I do not believe staggi= ng is based on RPM but instead Manifold Pressure (MP).  By default, = IIRC, Tracy has it at 15.5.  Should that conflict to a cruise or oft= en used setting, such as on final, it is pretty easily changed by selecting....I think, Mode 7, increasing the throttle to the = desired MP and then pressing the Program button when at the desired MP/RP= M.  That will set it to that chosen MP/RPM.  FWIW.
 
All the best,
 
Chris Barber
Houston
 
 
Cpl Christopher Barber, = JD.
Badge 330
Bellaire Police Departme= nt
5100 Jessamine
Bellaire, Texas 77401
 
From: Rotary motors in aircraft [= flyrotary@lancaironline.net] On Behalf Of George Lendich [lendich@aanet.c= om.au]
Sent: Tuesday, October 13, 2009 3:48 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: intake manifold 13b 86

Lynn,
About what RPM does the secondaries = come in, if I go by memory, which isn't always the best thing for mew to = do, It's about 3500 rpm - does that sound right?
George (down under)
That would be like disabling one of the intake valves in a 4 valve p= er cylinder piston engine. Yes it will still run but the power would be d= own somewhat.  Just not a good idea.
 
Tracy

On Mon, Oct 12, 2009 at 4:24 PM, jrhopkins <jrhopkins@windstream.net> wrote:
has anyone used blocked off the cent= er two apertures and used the front and rear intake manifolds only? = i do not understand the need for the center split intake for aircraft us= e.  
 
thanks   Richard
 
 
The center ports are smaller (the primary ports in the center iron) = are part of a system designed to use a carburetter. That means that high = velocity was needed to keep the energy high and the fuel air mixture= from forming droplets and adding to HC. 
 
So the smaller barrels of the 4 barrel carb open first to operate th= e engine on the high velocity runners to those ports. Most of the time&nb= sp; the engine ran only on those ports. So the effect is that the carb lo= oks small and the fuel mileage is fair, and HC (unburned Hydrocarbons) are within requirements. 
 
The key is velocity. The smaller the tube per cubic foot of mixture = per second, the higher the velocity. So the center ports and runners are = small. Since only about 20 HP is needed to go 60 MPH, most of the engines= life is run out on the small ports. 
 
When more power is demanded, low manifold pressure opens the seconda= ries in the carb via a vacuum diaphragm and the big ports in the front an= d rear irons are called into use. The fuel economy idea is out the window= and in a properly tuned car the engine RPM will be high enough to provide fair velocity in the big runners and = ports. So the engine will accelerate to the best power RPM (red line) to = deliver the engines rated HP.  
 
In the fuel injected engine this feature is still in use so you see = the throttle bodies  multiple inlets.
Same idea.
 
In aircraft use, there is little use for 20 HP beyond a slow taxi. T= ake off power would be everything you can come up with HP wise. So all 4 = ports and runners are needed. Once in flight, close to 50 HP would be nee= ded just to maintain level slow flight, so there is just no application where the plane would fly on just the ce= nter ports. As the plane climbs the available HP goes down based on air d= ensity changes,
so in most cases, the throttle is left at wide open or very close to= that. Further power reduction is by leaning to maintain the ideal fuel a= ir mixture, or even leaning further to well over lean, or Lean Of Peak.
That is Lean Of Peak EGT (the rotary does that very well), So power = goes down as well as fuel consumption and EGT. The throttle will be left = wide open.
 
Closing off the center ports would be the same as not opening the th= rottle by some amount.
 
If you want to build in more power, the 84-85 12A has the biggest ru= nners and ports in the center iron.
 
Lynn E. Hanover


Warning: This e-mail transmission, and any documents, files or previo= us e-mails attached to it, may contain confidential information that is l= egally privileged. If you are not the intended recipient or the person re= sponsible for delivering it to the intended recipient, you are hereby not= ified that any disclosure, copying, distribution or use of any of the inf= ormation contained in or attached to this transmission is STRICTLY PROHIB= ITED. If you have received this transmission in error, please immediately= notify us by telephone at 713-662-8132 and destroy the original transmis= sion and its attachments without reading them. Thank you.

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