Return-Path: Received: from imo-m28.mx.aol.com ([64.12.137.9] verified) by logan.com (CommuniGate Pro SMTP 4.3c1) with ESMTP id 723190 for flyrotary@lancaironline.net; Thu, 10 Feb 2005 00:57:44 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.9; envelope-from=WRJJRS@aol.com Received: from WRJJRS@aol.com by imo-m28.mx.aol.com (mail_out_v37_r3.8.) id q.2b.6c79a555 (17526) for ; Thu, 10 Feb 2005 00:56:57 -0500 (EST) From: WRJJRS@aol.com Message-ID: <2b.6c79a555.2f3c51a8@aol.com> Date: Thu, 10 Feb 2005 00:56:56 EST Subject: Re: [FlyRotary] Same HP = Same Air Mass <> same air Velocity [FlyRotary] Re: ... To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1108015016" X-Mailer: 9.0 SE for Windows sub 5005 -------------------------------1108015016 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 2/9/2005 7:00:00 PM Pacific Standard Time, eanderson@carolina.rr.com writes: So if the rotary has less displacement of the sucking component and must take 25% longer for each revolution. Therefore the only way it can obtain an equal amount of air is for the intake air to have a higher velocity than the Lycoming does. The air velocity of the area in the intake for the rotary would appear to have to be much higher than the Lycoming. If my assumptions and calculations are correct that would imply (at least to me) that to minimize air flow restriction a larger opening would be required on the rotary compared to the same HP Lycoming. Its not that one is taken in more air its that the rotary has less time and smaller displacement pump so must take in the air at a higher velocity Ed, you have a good cut on the discussion, with one other variant to add in. There is flow stopage in the rotary in the overlap phase so the easiest way for the tuning to work is low restriction. You can use a single throttle body but it better be a big one. Air has mass which is why tuning works at all. The correct length inlet tube keeps the air moving toward the chamber durring the overlap phase. You are right on about the timing which is why a no-compromise intake like the Le Mans engine uses the variable length inlets that get shorter at high RPMs. The shorter time to cram in the air, (higher RPM), the less restriction you must have to extract the most out of the engine. On the latest F1 engines 18K RPM is common, that's why they have an intake tract about 3-5 inches long. They started the showerhead style injection because the length is so short that shooting across the plenum allowed milliseconds longer for the fuel to vaporize. Pretty extreem stuff. Your comments about rotor speed also indicated why we need longer intakes than piston engines for the same shaft RPM. The rotor turns slower than the E-shaft so our intake event is like a piston engine turnig over slower. Bill Jepson -------------------------------1108015016 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
In a message dated 2/9/2005 7:00:00 PM Pacific Standard Time,=20 eanderson@carolina.rr.com writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
So if the rotary has less displacement of= the=20 sucking component and must take 25% longer for each revolution. =20 Therefore the only way it can obtain an equal amount of air is for the int= ake=20 air to have a higher velocity than the Lycoming does.
 
The air velocity of the area in the intak= e for=20 the rotary would appear to have to be much higher than the Lycoming. = If=20 my assumptions and calculations are correct that would imply (at least to=20= me)=20 that to minimize air flow restriction a larger opening would be requi= red=20 on the rotary compared to the same HP Lycoming.  Its not that on= e is=20 taken in more air its that the rotary has less time and smaller displaceme= nt=20 pump so must take in the air at a higher=20 velocity
Ed, you have a good cut on the discussion, with one other variant to ad= d=20 in. There is flow stopage in the rotary in the overlap phase so the easiest=20= way=20 for the tuning to work is low restriction. You can use a single throttle bod= y=20 but it better be a big one. Air has mass which is why tuning works at all. T= he=20 correct length inlet tube keeps the air moving toward the chamber durring th= e=20 overlap phase. You are right on about the timing which is why a no-compromis= e=20 intake like the Le Mans engine uses the variable length inlets that get shor= ter=20 at high RPMs. The shorter time to cram in the air, (higher RPM), the less=20 restriction you must have to extract the most out of the engine. On the late= st=20 F1 engines 18K RPM is common, that's why they have an intake tract about 3-5= =20 inches long. They started the showerhead style injection because the length=20= is=20 so short that shooting across the plenum allowed milliseconds longer for the= =20 fuel to vaporize. Pretty extreem stuff. Your comments about rotor speed also= =20 indicated why we need longer intakes than piston engines for the same shaft=20= RPM.=20 The rotor turns slower than the E-shaft so our intake event is like a piston= =20 engine turnig over slower.
Bill Jepson
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