Return-Path: Received: from ms-smtp-01.southeast.rr.com ([24.93.67.82] verified) by logan.com (CommuniGate Pro SMTP 4.1.3) with ESMTP id 2583698 for flyrotary@lancaironline.net; Wed, 17 Sep 2003 22:56:46 -0400 Received: from o7y6b5 (clt78-020.carolina.rr.com [24.93.78.20]) by ms-smtp-01.southeast.rr.com (8.12.5/8.12.2) with SMTP id h8I2nM0R001363 for ; Wed, 17 Sep 2003 22:49:23 -0400 (EDT) Message-ID: <011901c37d90$37076520$1702a8c0@WorkGroup> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Intake questions Date: Wed, 17 Sep 2003 22:54:44 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0116_01C37D6E.AFC36A80" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 This is a multi-part message in MIME format. ------=_NextPart_000_0116_01C37D6E.AFC36A80 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message ----- Original Message -----=20 From: Russell Duffy=20 To: Rotary motors in aircraft=20 Sent: Wednesday, September 17, 2003 12:01 PM Subject: [FlyRotary] Intake questions Greetings, I'm probably about to prove that I haven't paid any attention to any = of the intake construction threads, but here goes... I know there's = special length that will tune the intake to make more power. Ed knows = what this is, but if he tells us, he has to kill us (a slow painful = death, involving 60 slides) :-) =20 My general question is this- does it matter if this runner length is = before, or after the throttle body? I'm using the TWM throttle body, = which is completely separated into two sides. If I kept the air inlet = to the TB as separate tubes for a particular length, would that count = towards the tuned system? =20 The reason I'm thinking about this of course is pre-planning for the = almost inevitable removal of my turbo. If I end up using a stock cowl, = I'll have space in the left cheek for intake stuff. I've seen a very = short intake manifold that sticks straight out to the side about 4 = inches or so, then the TB would stick straight out another 4 inches or = so. While this is simple, and compact, it would certainly not be good = for our power band, so I started wondering if I could "tune" it with = individual pipes on the inlet side of the TB. =20 Thanks, Rusty (Scotty, I need more power!)=20 The short answer is that for the DIE effect, you need the runners = between the TB and intake port For you Rusty, you have to sit throught the presentation TWICE! The = answer is (I love this ) is- it depends. There are numerous approaches = to "induction tuning" (as you now) , there are even more theories from = the yard tree to the NASCAR chief mechanic's favorite one. Depending on = whether you adopt "Organ Pipe", "Helmhotz", "Finite-Amplitude Wave = theory" Or WHAT, you are likely to get different answers. However, there are a couple of things that appear to fall out of most = theories and practice. 1. Long small tubes make for good low-to mid range torque and power, = but tend to fall off at higher RPM. Now define "small", Tracy Crook's = engine probably has some of (if not the smallest) diameter tubes and has = done 214 MPH. 2. Short large tubes tend to make good High RPM range torque and = power (mainly power) but tend to suck at low - mid rpms 3. Airflow velocity in the tubes should be at some minimum velocity = for good combustion chamber stuffing with air/fuel mixture. The min = velocities I have seen in literature range from 180 ft/sec to mach 0.6 = (now that helps narrow it down doesn't it?) The basic bottom line seems to be that you can't have everything and = trying to get it will most likely end with a poor set up. I orginially = had a very similar set up, at 4 injector TMW throttle body sitting on a = Racing Beat webber system manifold. Dual 2" dia throats ready to turn = 10,000 rpm. Well, as I learned, the set up that's golden for 10,000 rpm = sucks at 5500 rpm. My second manifold was one I build copied after = Tracy Crooks (with some changes of course). Even my low power 1986 NA = 13B showed a climb improvment of 300 fpm and top speed increased 10 MPH = with the new manifold. My nominal static with a high pitch (68x72) prop = was 5200 rpm which I consider good - but on cool days I could turn it as = high as 5800 static. I took off one 28F morning turning 5800 rpm from = take off roll to 3000 msl with a fuel flow rate of 20 GPH indicating I = was producing over 200HP. Never thought to look at the VSI with my = eyeball glued to the rpm and fuel flow meter, but I got to 3000 ft = before I was much past the end of the runway. On the other hand, my top speed didn't seem to change! This type of = thing=20 is what got me started researching this DIE effect for an answer. The secret seems to be to clearly define what you want (compromise!) = out of the engine, then go about refining your intake system to fit = those needs. BUT, if you intend to employ this Dynamic Intake Effect (DIE) that you = will hear (at least twice {:>), the the answer is you must put your = runner length BETWEEN the trottle body and intake port. Let me make = one point clear about DIE, it is an adjunct to a basically good intake = system. If your basic induction system is D.. S... then DIE will not = pull the situation out of the mud. If you have a basically good intake that provides good airflow (no = doesn't have to be the perfect system) then DIE can indeed add enough = increased torque and power to make it worthwhile. Do you need it to fly = a rotary sucessfully - certainly not. But, if you want to twitk the = most HP from you installation with the minimum weight, I believe you = will find DIE potential highly interesting. Also it turns out there is no one magic runner length for the DIE = effect and the length for this effect depends not only on the rpm point = you select for this effect to occur but also on your particular engine = specifications - there that sounds mysterious enough, I think. So show up, Rusty. Fly, drive, swim or walk but be there. Best Regards Ed Anderson ------=_NextPart_000_0116_01C37D6E.AFC36A80 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
 
----- Original Message -----
From:=20 Russell=20 Duffy
Sent: Wednesday, September 17, = 2003 12:01=20 PM
Subject: [FlyRotary] Intake=20 questions

Greetings,
 
I'm probably = about to=20 prove that I haven't paid any attention to any of the intake = construction=20 threads, but here goes...  I know there's special length that = will tune=20 the intake to make more power.  Ed knows what this is, but if he = tells=20 us, he has to kill us (a slow painful death, involving 60 = slides) =20 :-) 
 
My general = question is=20 this- does it matter if this runner length is before, = or after the=20 throttle body?  I'm using the TWM throttle body, which is = completely=20 separated into two sides.  If I kept the air inlet to the TB as = separate=20 tubes for a particular length, would that count towards the tuned=20 system? 
 
The reason = I'm thinking=20 about this of course is pre-planning for the almost inevitable removal = of my=20 turbo.  If I end up using a stock cowl, I'll have space in = the left=20 cheek for intake stuff.  I've seen a very short intake manifold = that=20 sticks straight out to the side about 4 inches or so, then the TB = would stick=20 straight out another 4 inches or so.  While this is simple, and = compact,=20 it would certainly not be good for our power band, so I started = wondering if I=20 could "tune" it with individual pipes on the inlet side of the=20 TB.  
 
Thanks,
Rusty = (Scotty, I need=20 more power!) 
 
The short = answer is that=20 for the DIE effect, you need the runners between the TB and intake=20 port
 
For you = Rusty, you have=20 to sit throught the presentation TWICE!  The answer is (I love = this ) is-=20 it depends.  There are numerous approaches to "induction = tuning" (as=20 you now) , there are even more theories from the yard tree to the = NASCAR chief=20 mechanic's favorite one.  Depending on whether you adopt "Organ = Pipe",=20 "Helmhotz", "Finite-Amplitude Wave theory" Or WHAT, you are likely to = get=20 different answers.
 
However, = there are a=20 couple of  things that appear to fall out of most theories and=20 practice.
 
1.  Long = small tubes=20 make for good low-to mid range torque and power, but tend to fall off = at=20 higher RPM. Now define "small", Tracy Crook's engine probably has some = of (if=20 not the smallest) diameter tubes and has done 214 = MPH.
 
2.  = Short large=20 tubes tend to make good High RPM range torque and power (mainly power) = but=20 tend to suck at low - mid  rpms
 
3.  = Airflow velocity=20 in the tubes should be at some minimum velocity for good combustion = chamber=20 stuffing with air/fuel mixture.  The min velocities I have seen = in=20 literature range from 180 ft/sec to mach 0.6 (now that helps narrow it = down=20 doesn't it?)
 
 
The  = basic bottom=20 line seems to be that you can't have everything and trying to get it = will most=20 likely end with a poor set up.  I orginially had a very = similar set=20 up, at 4 injector TMW throttle body sitting on a Racing Beat webber = system=20 manifold. Dual 2" dia throats ready to turn 10,000 rpm.  Well, as = I=20 learned, the set up that's golden for 10,000 rpm sucks at 5500 = rpm.  My=20 second manifold was one I build copied after Tracy Crooks (with some = changes=20 of course).  Even my low power 1986 NA 13B showed a climb = improvment of=20 300 fpm and top speed increased 10 MPH with the new manifold.  My = nominal=20 static with a high pitch (68x72) prop was 5200 rpm which I = consider=20 good - but on cool days I could turn it as high as 5800=20 static.   I took off one 28F morning turning 5800 rpm from = take off=20 roll to 3000 msl with a fuel flow rate of 20 GPH indicating I was = producing over 200HP.  Never thought to look at the VSI with my = eyeball=20 glued to the rpm and fuel flow meter, but I got to 3000 ft before I = was much=20 past the end of the runway.
 
On the other = hand, my top=20 speed didn't seem to change!  This type of thing =
is what got = me started=20 researching this DIE effect for an answer.
 
 
The = secret seems=20 to be to clearly define what you want (compromise!) out of the engine, = then go=20 about refining your intake system to fit those = needs.
 
BUT, = if you intend=20 to employ this Dynamic Intake Effect (DIE) that you will hear (at = least twice=20 {:>), the the answer is you must put your runner length =  BETWEEN the=20 trottle body and intake port.  Let me make one point clear about = DIE, it=20 is an adjunct to a basically good intake system.  If your basic = induction=20 system is D.. S...  then DIE will not pull the situation out of = the=20 mud.
 
If = you have a=20 basically good intake that provides good airflow (no doesn't have to = be the=20 perfect system) then DIE can indeed add enough increased torque and = power to=20 make it worthwhile.  Do you need it to fly a rotary sucessfully - = certainly not.  But, if you want to twitk the most HP from you=20 installation with the minimum weight, I believe you will find DIE = potential=20 highly interesting.
 
Also = it turns out=20 there is no one magic runner length for the DIE effect and the length = for this=20 effect depends not only on the rpm point you select for =  this effect=20 to occur but also on your particular engine specifications - there = that sounds=20 mysterious enough, I think.
 
So = show up,=20 Rusty.  Fly, drive, swim or walk but be = there.
 
Best = Regards
 
Ed=20 Anderson
 
 
 
 
 
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