X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from poplet2.per.eftel.com ([203.24.100.45] verified) by logan.com (CommuniGate Pro SMTP 5.3.4) with ESMTP id 4181270 for flyrotary@lancaironline.net; Sun, 28 Mar 2010 00:35:54 -0400 Received-SPF: none receiver=logan.com; client-ip=203.24.100.45; envelope-from=lendich@aanet.com.au Received: from sv1-1.aanet.com.au (mail.aanet.com.au [203.24.100.34]) by poplet2.per.eftel.com (Postfix) with ESMTP id 5BC711739E3 for ; Sun, 28 Mar 2010 12:35:19 +0800 (WST) Received: from ownerf1fc517b8 (203.171.92.134.static.rev.aanet.com.au [203.171.92.134]) by sv1-1.aanet.com.au (Postfix) with SMTP id 89CD3BEC009 for ; Sun, 28 Mar 2010 12:35:18 +0800 (WST) Message-ID: From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: P-Port performance Date: Sun, 28 Mar 2010 14:35:20 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0015_01CACE83.E484DA70" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5843 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 X-Antivirus: avast! (VPS 100327-1, 03/27/2010), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_0015_01CACE83.E484DA70 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Joe, As Lynn mentioned 2" and then into the housing port where it's = reduced, is good. George ( down under) The nice thing about a 2" runner dia P Port is that if doesn't make = power at the desired rpm you could place a linner in the runners to = reduce the dia. A liitle harder to increase the runner dia without = disassembly. Thisof course depends on how many bends are in the = runners. Joe Berki ----- Original Message -----=20 From: Lehanover@aol.com=20 To: Rotary motors in aircraft=20 Sent: Saturday, March 27, 2010 1:40 AM Subject: [FlyRotary] Re: P-Port performance In a message dated 3/26/2010 8:58:41 PM Eastern Standard Time, = lendich@aanet.com.au writes: =E2=80=9Cthat things that work in one application (like Rx-7 = racing) just great - may well suck in another application.=E2=80=9D =20 Or not suck enough=E2=80=A6. ;) =20 Neilk Here is some more stuff to read, since none of you are building = right now.=20 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 = intake 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 is 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.=20 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 engine. And in road racing and drag racing, it is the first = person to his top speed that wins, not always the highest top speed.=20 Think gear ratio spreads, and area under the curve when you graph = HP.=20 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.=20 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 = calculate the ratio of your reduction unit, you know how fast you can = turn up your engine. And it isn't very much RPM.=20 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 to be where? 5,000 RPM with best HP at 5,800 or 6,000 RPM?=20 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 = where the airplane engine runs all of the time. This should be easy. = That length thing has to do with tuned length, or a pipe organ effect.=20 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.=20 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 = runner 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 port face.=20 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 valve timing we need, that bowl is too big (Too much volume). = Some folks fill this 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 causes the velocity to drop right where we = want the highest velocity.=20 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.=20 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. The best HP should be just before the top speed, so = you can lean away power and heat to get down to cruise RPM.=20 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. The engine will make power to well past 9,000 RPM in street trim, = if the breathing is available.=20 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 = holes. 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 idle 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 ------=_NextPart_000_0015_01CACE83.E484DA70 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable =EF=BB=BF
 
 Joe,
As Lynn mentioned 2" and then =  into the=20 housing  port where it's reduced, is good.
George ( down under)
 
The nice thing about a 2" runner dia P Port is that if doesn't = make power=20 at the desired rpm you could place a linner in the runners to reduce = the=20 dia.  A liitle harder to increase the runner dia without=20 disassembly.  Thisof course depends on how many bends are in the=20 runners.
 
Joe Berki
 
----- Original Message -----
From:=20 Lehanover@aol.com
To: Rotary motors in = aircraft=20
Sent: Saturday, March 27, = 2010 1:40=20 AM
Subject: [FlyRotary] Re: = P-Port=20 performance

In a message dated 3/26/2010 8:58:41 PM Eastern Standard Time, = lendich@aanet.com.au = writes:

=E2=80=9Cthat = things that=20 work in one application (like Rx-7 racing) just great - may well = suck in=20 another application.=E2=80=9D

 

Or not = suck=20 enough=E2=80=A6.  ;)

 

Neilk

Here is some more stuff to read, since none of you are = building=20 right now.
 
http://moto= tuneusa.com/think_fast_intake_porting.htm
 
This fellow fills in some cross section on the intake = runners of=20 big engine street and road race bikes.
 
Even the factory people fall in love with maximum HP = numbers to=20 sell bikes. The big numbers at the top RPM require big intake = runners. Big=20 intake runners means high flow velocity will be at astoundingly high = RPM.=20 This means the reverse will be available at mid and lower RPM. So, = the rider=20 is beaten silly on the road course by some weekend nitwit with a = smaller=20 engine, that appears to be stock. He obviously has less maximum HP, = but=20 seems to be doing quite well with his setup.
 
Because.......
 
The smaller engine has good torque and HP at lower and mid = range=20 RPM. Maybe he is not as fast at the end of the long straightaway, = but he=20 seems to get to  his top speed much sooner than the new bike = with the=20 bigger engine. And in road racing and drag racing, it is the first = person to=20 his top speed that wins, not always the highest top speed. =
 
Think gear ratio spreads, and area under the curve when you = graph=20 HP.
 
Racing engines and airplane engines are the same engines. = Some=20 racing organizations even use rev limiters to equalize competition = between=20 car brands to keep the racing interesting. So you have to imagine = that your=20 club, be it hair club for men or the home built airplane club has a = rule=20 about top RPM.
 
Of course the club has no such rule, but Mother nature does = have=20 such a rule. It has to do with the tip speed of propellers. So once = you=20 calculate the ratio of your reduction unit, you know how fast you = can turn=20 up your engine. And it isn't very much RPM.
 
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 torque=20 to 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=20 to lengthen the runners for low RPM. You might even say that low RPM = is=20 where the airplane engine runs all of the time. This should be easy. = That=20 length thing has to do with tuned length, or a pipe organ effect.=20
 
And our motorcycle friend above shows us that in order to = fill out=20 the mid range,(right where airplane engines run) you need to fill in = part of=20 the intake runners.
 
So folks are making errors at both ends of the runner. The = Throttle=20 body is so big that the last 1/3 to 1/4 of opening has no affect on = RPM.=20 Fortunately this has nearly no affect on HP. At the engine end = of the=20 runner just as in the stock intake manifold the runner needs to be = smaller=20 just as it mates with the block. So the highest flow velocity is = right at=20 the port face.
 
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 get=20 the valve timing we need, that bowl is too big (Too much volume). = Some folks=20 fill this in a bit with epoxy products. Some folks make it worse by=20 increasing the port timing but that makes the bowl volume increase. = The bowl=20 volume causes the velocity to drop right where we want the highest = velocity.=20
 
Some folks make Periphery port engines with 2" tubing run = from 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.
 
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 range.=20 The 2 inch pipe flattened slightly, or a dart removed to reduce the = ID about=20 15% or a bit more. would keep the velocity high, where it needs to = be high.=20 The best HP should be just before the top speed, so you can lean = away power=20 and heat to get down to cruise RPM.
 
Like the racer you want to be first to your top speed. If = you have=20 to pull off throttle to stay at cruise RPM, add some prop and test = again.=20 The engine will make power to well past 9,000 RPM in street trim, if = the=20 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=20 holes. My side port 12-As can do 250 HP at 9,400 RPM breathing = through two=20 38MM holes. My intake manifold gasket is stock. The runners at the = port face=20 are the street diameter and shape. A 12-A is 2,292 CCs, a 13-B is = 2,606CCs.=20 These engines are not dynoed below 7,000 RPM, because they have no = power at=20 all below that RPM it is pointless to test there. They are towed to = the=20 false grid with little tractors because they have no torque  at = all and=20 they idle at 2,200 RPM.
 
So if you keep building racing 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. Of course I could be completely = wrong.
 
Lynn E.=20 Hanover   
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