X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-we0-f180.google.com ([74.125.82.180] verified) by logan.com (CommuniGate Pro SMTP 5.4.3) with ESMTPS id 5353990 for flyrotary@lancaironline.net; Tue, 17 Jan 2012 15:04:31 -0500 Received-SPF: pass receiver=logan.com; client-ip=74.125.82.180; envelope-from=msteitle@gmail.com Received: by werm10 with SMTP id m10so1640371wer.25 for ; Tue, 17 Jan 2012 12:03:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=EgvMyF1/AXWOUIfKmYlcBpepjwFzMhFtLwF8oWDbzqQ=; b=E7d3npLyF57CggF2Cy4tSeflH1ht+09iEq42FuL7yBGxQHWwuIZbv1KJCjE5xY0C3w zl3aFL0jNHRbn3l5irkrJ8nL/uBpgtZnBXv9RvTmlDHjntbA44ESI7+M13/khjZdG66t ZhP3pppxP9PF6w+loh36S6gN/QrFNlWpGjWU0= MIME-Version: 1.0 Received: by 10.216.131.91 with SMTP id l69mr5043298wei.28.1326830634904; Tue, 17 Jan 2012 12:03:54 -0800 (PST) Received: by 10.223.105.211 with HTTP; Tue, 17 Jan 2012 12:03:54 -0800 (PST) In-Reply-To: References: Date: Tue, 17 Jan 2012 14:03:54 -0600 Message-ID: Subject: Re: [FlyRotary] Re: tuning advice From: Mark Steitle To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=0016e6db2966abad4604b6bed469 --0016e6db2966abad4604b6bed469 Content-Type: text/plain; charset=ISO-8859-1 Lynn, Your statement, "Everything affects everything else" is etched in my brain from a posting long ago. I can definitely agree with your statements relating to the exhaust system. I'm on #4, or is it #5, I've lost count. Most of them were destroyed in a few short hours. The current one works pretty well, best I can tell from flight numbers. Sure wish you lived in Texas, I'd fly up and get you to perform some of your magic on my engine. ;-) With all that said, its running better now than it ever has before, except for idle speed. But then the p-port won't ever win the contest for smoothest idle. So, I guess I just won't idle it much. Thanks for sharing your wisdom. Ernest - Good suggestion on the rotary engine book, I guess I should pour me a glass of wine and read through it cover to cover. Mark On Tue, Jan 17, 2012 at 12:15 PM, wrote: > ** > > > In a message dated 1/17/2012 6:47:41 A.M. Eastern Standard Time, > msteitle@gmail.com writes: > > Lynn, > > Thanks so much for a very detailed reply. It sounds like the factory EC-2 > setting for advance will be pretty close for cruise (5200 rpm) mode for my > p-port engine. I usually lean pretty aggressively, so maybe a couple of > degrees would be in order. > > Can you tell me if its normal for the MAP to be different for p-port > engines, particularly around idle (1800 rpm)? My MAP readings are approx. > 17.0 - 17.3 at idle. This is about 2" higher that with my side-port > engine. I'm thinking this is because of the much higher intake/exhaust > overlap with the p-port engine. > > Thanks, > Mark > > > Everything affects everything, all of the time. > > So where the side port can have less overlap, or even no overlap in the > case of the Renesis, the Pport has a lot of overlap. So, the Pport is > easily affected by exhaust system and muffler design. At any particular RPM > a wildly differing set of factors plays out inside the engine. The most > obvious is the exhaust gasses re-entering the chamber diluting the intake > charge, and making it over rich (because some of the oxygen bearing charge > has be displaced and the fuel delivery has remained unchanged. This whole > scenario may change just a few RPM up or down the range. > > So you might get it idling really well today, and in the morning it barely > runs at all until the oil temps come up a bit. What could cause that? The > cold rotors are condensing fuel back into droplets, which makes for less > surface area to mate up with any oxygen, and the engine is now very much > over lean. Everything affects everything. > > If you have fiddled with dirt bike engines, this all comes to be very > clear. There is a similar interaction between intake design and exhaust > design in a piston port 2 cycle engine. > > Notice the strange mufflers on those bikes. A seemingly over sized muffler > ending with a very small tube that seems far too small to make any power. > And still it works. > > The rotary is a 4 stroke Otto cycle engine that tunes like a 2 stroke dirt > bike engine. > Less so for little or no overlap. Much more so for lots of overlap like > the Pport. > > So, it will never tune up in idle quite as well as a side port. But the > higher the idle RPM you can stand the better it will be. Another factor > that removes the engine from its car like idle, is the fact that the prop > load is higher than the engine would see in just stirring up trans oil at > idle. So instead of say 3 HP required to idle you may need12 or 15 HP to > spin that prop even 1,000 RPM. > > Your first Viking departure will make it all worth the trip. > > Lynn E. Hanover > > > --0016e6db2966abad4604b6bed469 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Lynn,=A0

Your statement, "Everything affects everyt= hing else" is etched in my brain from a posting long ago. =A0
=
I can definitely agree with your statements relating to the = exhaust system. =A0I'm on #4, or is it #5, I've lost count. =A0Most= of them were destroyed in a few short hours. =A0The current one works pret= ty well, best I can tell from flight numbers. =A0Sure wish you lived in Tex= as, I'd fly up and get you to perform some of your magic on my engine. = =A0;-) =A0

With all that said, its running better now than it ever= has before, except for idle speed. =A0But then the p-port won't ever w= in the contest for smoothest idle. =A0So, I guess I just won't idle it = much. =A0=A0

Thanks for sharing your wisdom.

Ernest - Good suggestion on the rotary engine book, I guess I should pour= me a glass of wine and read through it cover to cover. =A0

Mark
=A0

On T= ue, Jan 17, 2012 at 12:15 PM, <Lehanover@aol.com> wrote:
=A0
Everything affects everything, all of the time.
=A0
So where the side port can have less overlap, or even no overlap in th= e=20 case of the Renesis, the Pport has a lot of overlap. So, the Pport is easil= y=20 affected by exhaust system and muffler design. At any particular RPM a wild= ly=20 differing set of factors plays out inside the engine. The most obvious is t= he=20 exhaust gasses re-entering the chamber diluting the intake charge, and maki= ng it=20 over rich (because some of the oxygen bearing charge has be displaced and t= he=20 fuel delivery has remained unchanged. This whole scenario may change just a= few=20 RPM up or down the range.
=A0
So you might get it idling really well today, and in the morning it ba= rely=20 runs at all until the oil temps come up a bit. What could cause that? The c= old=20 rotors are condensing fuel back into droplets, which makes for less surface= area=20 to mate up with any oxygen, and the engine is now very much over lean.=20 Everything affects everything.
=A0
If you have fiddled with dirt bike engines, this all comes to be very= =20 clear. There is a similar interaction between intake design and exhaust des= ign=20 in a piston port 2 cycle engine.
=A0
Notice the strange mufflers on those bikes. A seemingly over sized muf= fler=20 ending with a very small tube that seems far too small to make any power. A= nd=20 still it works.
=A0
The rotary is a 4 stroke Otto cycle engine that tunes like a 2 stroke = dirt=20 bike engine.
Less so for little or no overlap. Much more so for lots of overlap lik= e the=20 Pport.
=A0
So, it will never tune up in idle quite as well as a side port. But th= e=20 higher the idle RPM you can stand the better it will be. Another factor tha= t=20 removes the engine from its car like idle, is the fact that the prop load i= s=20 higher than the engine would see in just stirring up trans oil at idle. So= =20 instead of say 3 HP required to idle you may need12 or 15 HP to spin that p= rop=20 even 1,000 RPM.
=A0
Your first Viking departure will make it all worth the trip.=A0
=A0
Lynn E. Hanover


--0016e6db2966abad4604b6bed469--