X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-qy0-f204.google.com ([209.85.221.204] verified) by logan.com (CommuniGate Pro SMTP 5.3.4) with ESMTP id 4181442 for flyrotary@lancaironline.net; Sun, 28 Mar 2010 08:20:53 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.221.204; envelope-from=rwstracy@gmail.com Received: by qyk42 with SMTP id 42so1637550qyk.7 for ; Sun, 28 Mar 2010 05:20:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:sender:received:in-reply-to :references:date:x-google-sender-auth:received:message-id:subject :from:to:content-type; bh=pM3lTvWfsGTupFKDRAq1aWZmavOD+XRc0BfLtS5KZd4=; b=mFtaLsDO1ZVki9LlHxD81LwvTO9xFN4VHtXoxvekjgogbmafTj3En+9ggVGhmab/Oq h1dXvewXO/I44zn5Wnpqd7zxdajEfuMbNgoDPSIiW8AZa+zpik82sogd4eG/4Hcnx2Gr QkNY0YhM8nhxBHzZgVDhjbsxFo5COl9Gjym90= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:content-type; b=R0gUyadYyOY/jdncCbb8Nr/6ISbgLOIqH84bL2p7e8IzRiusQdypd6/9jFtMZjYNTO wNSTMpaig3VKjkKF1qylgeDLyaa1D4HcMpausnDKj/6gNNMvo/imIm4YI87uQuUiRAna oRGOTjdZ2x0v+VFj0x364iAb99LCTQ3hf1VoQ= MIME-Version: 1.0 Sender: rwstracy@gmail.com Received: by 10.224.60.211 with HTTP; Sun, 28 Mar 2010 05:20:16 -0700 (PDT) In-Reply-To: References: Date: Sun, 28 Mar 2010 08:20:16 -0400 X-Google-Sender-Auth: 400681021ed4ea07 Received: by 10.224.30.82 with SMTP id t18mr1262285qac.355.1269778817032; Sun, 28 Mar 2010 05:20:17 -0700 (PDT) Message-ID: <1b4b137c1003280520y22ba3c09jda4d3c413fb4b5aa@mail.gmail.com> Subject: Re: [FlyRotary] Re: P-Port performance From: Tracy Crook To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=000feaef43ba5525b00482db6b03 --000feaef43ba5525b00482db6b03 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable George, your numbers look reasonable. Only thing I would add is that the calculated runner speed is an average. The actual velocity in a running engine varies radically (it even reverses). The significant speed is peek velocity which is so high it is measured in Mach. Mach .6 or more is not uncommon in a well tuned engine. It is the energy in this peek velocity which allows better volumetric efficiency at the tuned rpm. Tracy On Sat, Mar 27, 2010 at 10:43 PM, George Lendich wrot= e: > Naturally I take on board all Lynn and Ed say, as they have helped me > understand how things work and Ed with the maths to give a ball park figu= re > rather than a WAG, on performance. > > So I have condensed the figures Ed gave me a tried to make it as simple a= s > possible to show others - see attached. I hope this helps those willing t= o > look into the maths. > > You will notice that the results strongly agree with what Lynn has stated > (in general terms). This in turn strongly agrees with what powersport was > using i.e. 40mm up to 6,000 rpm and 44mm up to 7,500rpm (checked this wit= h > Bill). What Lynn has suggested is 50mm reduced 15% 42.5mm - hello! I've s= een > that figure before - dia required at 7,200 rpm. I also agree with what Ly= nn > suggests on P-port shapes - I just find round easier to do, so round is > probably not optimum, but good enough for some. > > Some of the Renesis figures I've increased hp in line with compression > increase and rounded off some end result figures. > Hope it helps - it sure helped me. > George ( down under) > > =93that things that work in one application (like Rx-7 racing) just great= - > may well suck in another application.=94 > > > > Or not suck enough=85. ;) > > > > Neilk > > *Here is some more stuff to read, since none of you are building right > now. * > ** > *http://mototuneusa.com/think_fast_intake_porting.htm* > ** > *This fellow fills in some cross section on the intake runners of big > engine street and road race bikes.* > ** > *Even the factory people fall in love with maximum HP numbers to sell > bikes. The big numbers at the top RPM require big intake runners. Big int= ake > runners means high flow velocity will be at astoundingly high RPM. This > means the reverse will be available at mid and lower RPM. So, the rider i= s > beaten silly on the road course by some weekend nitwit with a smaller > engine, that appears to be stock. He obviously has less maximum HP, but > seems to be doing quite well with his setup. * > ** > *Because.......* > ** > *The smaller engine has good torque and HP at lower and mid range RPM. > Maybe he is not as fast at the end of the long straightaway, but he seems= to > get to his top speed much sooner than the new bike with the bigger engin= e. > And in road racing and drag racing, it is the first person to his top spe= ed > that wins, not always the highest top speed. * > ** > *Think gear ratio spreads, and area under the curve when you graph HP. * > ** > *Racing engines and airplane engines are the same engines. Some racing > organizations even use rev limiters to equalize competition between car > brands to keep the racing interesting. So you have to imagine that your > club, be it hair club for men or the home built airplane club has a rule > about top RPM. * > > *Of course the club has no such rule, but Mother nature does have such a > rule. It has to do with the tip speed of propellers. So once you calculat= e > the ratio of your reduction unit, you know how fast you can turn up your > engine. And it isn't very much RPM. * > > *So now you are unhappy with the torque of the car engine that had good > torque at 2,500 RPM in the street car, and now you want the best torque t= o > be where? 5,000 RPM with best HP at 5,800 or 6,000 RPM? * > > *Note that the car engine has short runners for high RPM and valving to > lengthen the runners for low RPM. You might even say that low RPM is wher= e > the airplane engine runs all of the time. This should be easy. That lengt= h > thing has to do with tuned length, or a pipe organ effect. * > > *And our motorcycle friend above shows us that in order to fill out the > mid range,(right where airplane engines run) you need to fill in part of = the > intake runners. * > > *So folks are making errors at both ends of the runner. The Throttle body > is so big that the last 1/3 to 1/4 of opening has no affect on RPM. > Fortunately this has nearly no affect on HP. At the engine end of the run= ner > just as in the stock intake manifold the runner needs to be smaller just = as > it mates with the block. So the highest flow velocity is right at the por= t > face. * > > *The rotary has a problem that involves the bowl shape below the opening > into the engine, valved by the sides of the rotor. In order to get the va= lve > timing we need, that bowl is too big (Too much volume). Some folks fill t= his > in a bit with epoxy products. Some folks make it worse by increasing the > port timing but that makes the bowl volume increase. The bowl volume caus= es > the velocity to drop right where we want the highest velocity. * > > *Some folks make Periphery port engines with 2" tubing run from some > distance that seems to make sense. This is a big help at RPM above where = you > can use it for anything. So at RPM lower than the ideal to take advantage= of > the Pport, there is less HP than a side port engine. * > > *The opening into the housing with a Pport is usually a round hole. Not > ideal. Later intake opening and earlier closing give you more mid range. = The > 2 inch pipe flattened slightly, or a dart removed to reduce the ID about = 15% > or a bit more. would keep the velocity high, where it needs to be high. T= he > best HP should be just before the top speed, so you can lean away power a= nd > heat to get down to cruise RPM. * > > *Like the racer you want to be first to your top speed. If you have to > pull off throttle to stay at cruise RPM, add some prop and test again. Th= e > engine will make power to well past 9,000 RPM in street trim, if the > breathing is available. * > > *If you want to go real fast, cool the oil.* > ** > *A 12-A can do 310 HP at 10,700 RPM breathing through two 44MM holes. My > side port 12-As can do 250 HP at 9,400 RPM breathing through two 38MM hol= es. > My intake manifold gasket is stock. The runners at the port face are the > street diameter and shape. A 12-A is 2,292 CCs, a 13-B is 2,606CCs. These > engines are not dynoed below 7,000 RPM, because they have no power at all > below that RPM it is pointless to test there. They are towed to the false > grid with little tractors because they have no torque at all and they id= le > at 2,200 RPM.* > ** > *So if you keep building racing engines and puting them into airplanes > that operate below the bottom of the power band of the engine, why do you= do > that? Doctor, Doctor, it hurts when I do that. Quit doing that.* *Of > course I could be completely wrong.* > ** > *Lynn E. Hanover* > > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > > --000feaef43ba5525b00482db6b03 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable George, your numbers look reasonable.=A0 Only thing I would add is that the= calculated runner speed is an average.=A0 The actual velocity in a running= engine varies radically (it even reverses). The significant speed is peek = velocity which is so high it is measured in Mach.=A0 Mach .6 or more is not= uncommon in a well tuned engine.=A0 It is the energy in this peek velocity= which allows better volumetric efficiency at the tuned rpm.

Tracy

On Sat, Mar 27, 2010 at 10:43 P= M, George Lendich <lendich@aanet.com.au> wrote:
Naturally I take on board all Lynn and Ed say, as they have helped me= =20 understand how things work and=A0Ed with the maths to give a ball park figu= re=20 rather than a WAG, on performance.
=A0
So I have condensed the figures Ed gave me a tried to make it as simpl= e as=20 possible=A0to show others - see attached. I hope this helps those willing t= o=20 look into the maths.
=A0
You will notice that the results=A0strongly agree with what Lynn has= =20 stated (in general terms). This in turn strongly agrees with=20 what=A0powersport was using i.e. 40mm up to 6,000 rpm and 44mm up to 7,500r= pm=20 (checked this with Bill). What Lynn has suggested is 50mm reduced 15% 42.5m= m -=20 hello! I've seen that figure before - dia required at 7,200 rpm. I also= agree=20 with what Lynn suggests on P-port shapes - I just find round easier to do, = so=20 round is probably not optimum, but good enough for some.
=A0
Some of the Renesis figures I've increased hp in line with compres= sion=20 increase and rounded off some end result figures.
Hope it helps - it sure helped me.
George ( down under)
= =93that = things that work=20 in one application (like Rx-7 racing) just great - may well suck in anoth= er=20 application.=94

<= span style=3D"font-size: 10pt; color: navy; font-family: Arial;" lang=3D"EN= -US">=A0

<= span style=3D"font-size: 10pt; color: navy; font-family: Arial;" lang=3D"EN= -US">Or not suck=20 enough=85.=A0 ;)

<= span style=3D"font-size: 10pt; color: navy; font-family: Arial;" lang=3D"EN= -US">=A0

<= span style=3D"font-size: 10pt; color: navy; font-family: Arial;" lang=3D"EN= -US">Neilk

Here is some more stuff to read, since none of you are building r= ight=20 now.
=A0
=A0
This fellow fills in some cross section on the intake runners of = big=20 engine street and road race bikes.
=A0
Even the factory people fall in love with maximum HP numbers to s= ell=20 bikes. The big numbers at the top RPM require big intake runners. Big int= ake=20 runners means high flow velocity will be at astoundingly high RPM. This m= eans=20 the reverse will be available at mid and lower RPM. So, the rider is beat= en=20 silly on the road course by some weekend nitwit with a smaller engine, th= at=20 appears to be stock. He obviously has less maximum HP, but seems to be do= ing=20 quite well with his setup.
=A0
Because.......
=A0
The smaller engine has good torque and HP at lower and mid range = RPM.=20 Maybe he is not as fast at the end of the long straightaway, but he seems= to=20 get to=A0 his top speed much sooner than the new bike with the bigger=20 engine. And in road racing and drag racing, it is the first person to his= top=20 speed that wins, not always the highest top speed.
=A0
Think gear ratio spreads, and area under the curve when you graph= HP.=20
=A0
Racing engines and airplane engines are the same engines. Some ra= cing=20 organizations even use rev limiters to equalize competition between car b= rands=20 to keep the racing interesting. So you have to imagine that your club, be= it=20 hair club for men or the home built airplane club has a rule about top RP= M.=20
=A0
Of course the club has no such rule, but Mother nature does have = such=20 a rule. It has to do with the tip speed of propellers. So once you calcul= ate=20 the ratio of your reduction unit, you know how fast you can turn up your= =20 engine. And it isn't very much RPM.
=A0
So now you are unhappy with the torque of the car engine that had= =20 good torque at 2,500 RPM in the street car, and now you want the best tor= que=20 to be where? 5,000 RPM with best HP at 5,800 or 6,000 RPM?
=A0
Note that the car engine has short runners for high RPM and valvi= ng=20 to lengthen the runners for low RPM. You might even say that low RPM is w= here=20 the airplane engine runs all of the time. This should be easy. That lengt= h=20 thing has to do with tuned length, or a pipe organ effect.
=A0
And our motorcycle friend above shows us that in order to fill ou= t=20 the mid range,(right where airplane engines run) you need to fill in part= of=20 the intake runners.
=A0
So folks are making errors at both ends of the runner. The Thrott= le=20 body is so big that the last 1/3 to 1/4 of opening has no affect on RPM.= =20 Fortunately this has=A0nearly no affect on HP. At the engine end of the= =20 runner just as in the stock intake manifold the runner needs to be smalle= r=20 just as it mates with the block. So the highest flow velocity is right at= the=20 port face.
=A0
The rotary has a problem that involves the bowl shape below the= =20 opening into the engine, valved by the sides of the rotor. In order to ge= t the=20 valve timing we need, that bowl is too big (Too much volume). Some folks = fill=20 this in a bit with epoxy products. Some folks make it worse by increasing= the=20 port timing but that makes the bowl volume increase. The bowl volume caus= es=20 the velocity to drop right where we want the highest velocity.
=A0
Some folks make Periphery port engines with 2" tubing run fr= om some=20 distance that seems to make sense. This is a big help at RPM above where = you=20 can use it for anything. So at RPM lower than the ideal to take advantage= of=20 the Pport, there is less HP than a side port engine.
=A0
The opening into the housing with a Pport is usually a round hole= .=20 Not ideal. Later intake opening and earlier closing give you more mid ran= ge.=20 The 2 inch pipe flattened slightly, or a dart removed to reduce the ID ab= out=20 15% or a bit more. would keep the velocity high, where it needs to be hig= h.=20 The best HP should be just before the top speed, so you can lean away pow= er=20 and heat to get down to cruise RPM.
=A0
Like the racer you want to be first to your top speed. If you hav= e to=20 pull off throttle to stay at cruise RPM, add some prop and test again. Th= e=20 engine will make power to well past 9,000 RPM in street trim, if the brea= thing=20 is available.
=A0
If you want to go real fast, cool the oil.
=A0
A 12-A can do 310 HP at 10,700 RPM breathing through two 44MM hol= es.=20 My side port 12-As can do 250 HP at 9,400 RPM breathing through two 38MM= =20 holes. My intake manifold gasket is stock. The runners at the port face a= re=20 the street diameter and shape. A 12-A is 2,292 CCs, a 13-B is 2,606CCs. T= hese=20 engines are not dynoed below 7,000 RPM, because they have no power at all= =20 below that RPM it is pointless to test there. They are towed to the false= grid=20 with little tractors because they have no torque=A0 at all and they idle = at=20 2,200 RPM.
=A0
So if you keep building=A0racing engines and puting them into=20 airplanes that operate below the bottom of the power band of the engine, = why=20 do you do that? Doctor, Doctor, it hurts when I do that. Quit doing=20 that.=A0Of course I could be completely wrong.
=A0
Lynn E. Hanover=A0=A0=A0

--
Homepage: =A0http:/= /www.flyrotary.com/
Archive and UnSub: =A0 http://mail.lancaironline.net:81/lists= /flyrotary/List.html


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