X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from access.aic-fl.com ([207.30.253.2] verified) by logan.com (CommuniGate Pro SMTP 5.1.11) with ESMTP id 2270651 for flyrotary@lancaironline.net; Sat, 18 Aug 2007 10:28:02 -0400 Received-SPF: softfail receiver=logan.com; client-ip=207.30.253.2; envelope-from=unicorn@gdsys.net Received: from main (gdsi-46.gdsys.net [207.30.255.46]) by access.aic-fl.com (Rockliffe SMTPRA 4.5.6) with SMTP id for ; Sat, 18 Aug 2007 09:23:41 -0500 Message-ID: <003001c7e1a3$ea0d7da0$2eff1ecf@main> From: "Richard Sohn" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Power! More Power, Scotty! was [FlyRotary] Re: Air/fuel flow Date: Sat, 18 Aug 2007 09:27:26 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_002A_01C7E179.FDA2B620" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_002A_01C7E179.FDA2B620 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Nevertheless, Lynn,s comments safed my day. I was trying to tune the single rotor over the past few weeks. Using a = 38mm Mikuni round slide, I got it to idle clean up from 1600rpm. = Transition into midrange and up to WOT is no problem. Trying to get the = mixture richer at WOT, I did not get the responce to enlarging the main = jet I expected. The mixture stayed lean, indicated by high EGT and white = plug insulators, to some extend suported by the O2 reading. The air flow = rate at 6000 rpm is almost double of what Mikuni says is max. I started = wondering. Now Lynn said " carbs get leaner to the top of their RPM ranges" . There = may be the answer to my problem: bigger carb! Richard Sohn N2071U ----- Original Message -----=20 From: Ed Anderson=20 To: Rotary motors in aircraft=20 Sent: Saturday, August 18, 2007 8:22 AM Subject: [FlyRotary] Power! More Power, Scotty! was [FlyRotary] Re: = Air/fuel flow Lynn's summation says it all (if it ever is all said {:>)). The bottom line is that atmospheric oxygen to support combustion is = the limitation in making power. You can always add more fuel if you = could just get more air/oxygen into the combustion chamber. Using atmospheric pressure alone there is only so much pressure to = force air (approx 20% oxygen) into the combustion chamber. Some = combination of tuning can improve on chamber stuffing over atmospheric = pressure alone, but I think even here you are only talking about = 105-110% VE. To really increase power beyond this point you either need = to go to some sort of forced induction or to an oxidizer like nitrous = oxide to provide more oxygen to burn more fuel to made more power. But, other than that - volumetric flow (CFM) says it all. Anything = done to improve it aids power, but unfortunately, the things done to = improve it at one rpm may well hurt VE at another rpm. So pick your = power band and tune your induction system accordingly. Ed ----- Original Message -----=20 From: Lehanover@aol.com=20 To: Rotary motors in aircraft=20 Sent: Saturday, August 18, 2007 8:37 AM Subject: [FlyRotary] Re: Air/fuel flow In a message dated 8/18/2007 3:13:31 A.M. Eastern Daylight Time, = lendich@optusnet.com.au writes: Lynn, The question was on inlet velocity for a Mazda rotary at 7,500 rpm = - if you happened to have some info on that. Everyday cars have 450' per sec and race cars 125' per second,( = suggested on a carb site) Ed's calculations used 176' per second which = indicated a bigger inlet diameter. I was thinking about 300 to 350' per = second would more like it, but I have no real hard data! Well then let me speculate.=20 The engines have two RPM where they wander above 100% VE. These are = too low to help us much but the car designers use this and stretch it = out a bit looking at the pipe organ intakes. Just off idle and about 2,000 RPM. This confuses the idle and = transition circuits in the Weber and you get a nice = Rumppp...Rumppp...Rumppp. Breathing is very good compared to a piston = engine, and runner diameter is small for any HP output. The stock intake = manifold gasket in my engines (Daryl Drummond) is barely enlarged at = all. The new engine may have more than two such RPM. Porting extends the intake open time and makes for a more turbine = like flow. Even a street port can nearly double the stock HP, and that = would require nearly double the stock airflow. Down low the race or even = street ported engine has little advantage over the stock engine. For any = RPM the air flow determines the HP output, so where (RPM) you are = interested in output there will need to be dramatically improved = airflow.=20 So generally, the displacement times the RPM minus some percentage = for inlet restriction based on TP size or carb choke size and or runner = length and diameter will be the stock situation and one CFM value. And in a modified intake system with longer runners of slightly more = diameter which will favor the same RPM as the stock example engine will = have very much more power than a stock engine at the same RPM, = indicating a much higher than stock (CFM) air flow. Maybe not over 100% = VE but much closer to that number than the stock engine.=20 There is no cheating possible here. So if your example engine is = compared to any other engine with more power at the same RPM. The higher = power output requires very much more airflow, not less.=20 Something is amiss Watson.........I can feel it! Lynn E. Hanover =20 -------------------------------------------------------------------------= --- Get a sneak peek of the all-new AOL.com. -------------------------------------------------------------------------= ----- No virus found in this incoming message. Checked by AVG Free Edition.=20 Version: 7.5.476 / Virus Database: 269.11.19/953 - Release Date: = 8/14/2007 5:19 PM ------=_NextPart_000_002A_01C7E179.FDA2B620 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Nevertheless, Lynn,s comments safed my day.
 
I was trying to tune the single rotor over the past few weeks. = Using a 38mm=20 Mikuni round slide, I got it to idle clean up from 1600rpm. Transition = into=20 midrange and up to WOT is no problem. Trying to get the mixture=20 richer at WOT, I did not get the responce to enlarging the = main jet I=20 expected. The mixture stayed lean, indicated by high EGT and white plug=20 insulators, to some extend suported by the O2 reading. The air flow rate = at 6000=20 rpm is almost double of what Mikuni says is max. I started = wondering.
Now Lynn said " carbs get leaner to the top of their RPM ranges" . = There=20 may be the answer to my problem: bigger carb!
 
Richard Sohn
N2071U
----- Original Message -----
From:=20 Ed=20 Anderson
Sent: Saturday, August 18, 2007 = 8:22=20 AM
Subject: [FlyRotary] Power! = More Power,=20 Scotty! was [FlyRotary] Re: Air/fuel flow

Lynn's summation says it all (if it ever is all = said=20 {:>)).
 
The bottom line is that atmospheric oxygen to = support=20 combustion is the limitation in making power.  You can always add = more=20 fuel if you could just get more air/oxygen  into the combustion=20 chamber.
 
Using atmospheric pressure alone there is only so = much=20 pressure to force air (approx 20% oxygen) into the combustion = chamber. =20 Some combination of tuning can improve on chamber stuffing over = atmospheric=20 pressure alone, but I think even here you are only talking about = 105-110%=20 VE.  To really increase power beyond this point you either need = to go to=20 some sort of forced induction or to an oxidizer like nitrous oxide to = provide=20 more oxygen to burn more fuel to made more power.
 
But, other than that - volumetric flow (CFM) = says it=20 all.  Anything done to improve it aids power, but unfortunately, = the=20 things done to improve it at one rpm may well hurt VE at another = rpm.  So=20 pick your power band and tune your induction system = accordingly.
 
Ed
 
 
----- Original Message -----
From:=20 Lehanover@aol.com
To: Rotary motors in = aircraft=20
Sent: Saturday, August 18, = 2007 8:37=20 AM
Subject: [FlyRotary] Re: = Air/fuel=20 flow

In a message dated 8/18/2007 3:13:31 A.M. Eastern Daylight = Time, lendich@optusnet.com.au=20 writes:
Lynn,
The question was on inlet velocity for a Mazda rotary at = 7,500 rpm -=20 if you happened to have some info on that.
 
Everyday cars have 450' per sec and race cars 125' per = second,(=20 suggested on a carb site) Ed's calculations used 176' = per second=20 which indicated a bigger inlet diameter. I was thinking about 300 = to 350'=20 per second would more like it, but I have no real hard=20 data!
Well then let me speculate.
 
The engines have two RPM where they wander above 100% VE. These = are too=20 low to help us much but the car designers use this and stretch it = out a=20 bit looking at the pipe organ intakes.
 
Just off idle and about 2,000 RPM. This confuses the idle and=20 transition circuits in the Weber and you get a=20 nice Rumppp...Rumppp...Rumppp. Breathing is very good compared = to a=20 piston engine, and runner diameter is small for any HP output. The = stock=20 intake manifold gasket in my engines (Daryl Drummond) is barely = enlarged at=20 all. The new engine may have more than two such RPM.
 
Porting extends the intake open time and makes for a more = turbine like=20 flow. Even a street port can nearly double the stock HP, and that = would=20 require nearly double the stock airflow. Down low the race or even = street=20 ported engine has little advantage over the stock engine. For any = RPM the=20 air flow determines the HP output, so where (RPM) you are interested = in=20 output there will need to be dramatically improved = airflow. 
 
So generally, the displacement times the RPM minus some = percentage for=20 inlet restriction based on TP size or carb choke size and or runner = length=20 and diameter will be the stock situation and one CFM value.
 
And in a modified intake system with longer runners of slightly = more=20 diameter which will favor the same RPM as the stock example = engine will=20 have very much more power than a stock engine at the same RPM, = indicating a=20 much higher than stock (CFM) air flow. Maybe not over 100% VE but = much=20 closer to that number than the stock engine.
 
There is no cheating possible here. So if your example engine = is=20 compared to any other engine with more power at the same RPM. The = higher=20 power output requires very much more airflow, not less.
 
Something is amiss Watson.........I can feel it!
 
Lynn E. Hanover   



Get a sneak peek of the all-new AOL.com.

No virus found in this incoming message.
Checked by AVG Free = Edition.
Version: 7.5.476 / Virus Database: 269.11.19/953 - = Release Date:=20 8/14/2007 5:19 PM
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