X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 50 [XX] Return-Path: Received: from ms-smtp-02.southeast.rr.com ([24.25.9.101] verified) by logan.com (CommuniGate Pro SMTP 5.1.8) with ESMTP id 2021678 for flyrotary@lancaironline.net; Wed, 02 May 2007 12:17:45 -0400 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.101; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-103-061.carolina.res.rr.com [24.74.103.61]) by ms-smtp-02.southeast.rr.com (8.13.6/8.13.6) with SMTP id l42GG5i5012226 for ; Wed, 2 May 2007 12:16:05 -0400 (EDT) Message-ID: <001d01c78cd5$5c375000$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Throttle body size/ other "Paul" issues Date: Wed, 2 May 2007 12:17:20 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_001A_01C78CB3.D4D238D0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3028 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3028 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_001A_01C78CB3.D4D238D0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Thanks, Bill for pointing out the subtle differences. I generally stay = with what my aircraft/engine likes even if I don't always have an = accurate understanding of what is going on. I don't care if larger TB = are "suppose" to be "better" - if my engine doesn't like it, then I = don't like it. {:>). I think the real message here is that our operating regime is different = from the racer and the better we understand those differences the more = optimum our system will be for operating regime. As yourself, Tracy, = Lynn (and others have put it) bigger is not always better. Folks like = yourself and Lynn who have real world experience with the racing side = (be it rotary engines or others) understand this. But for many, lacking = that experience, we try to "think" our way through it - which if you = don't understand the impact/influence of all the variables in all the = situations (and their very complex interaction) - just might lead you to = a false conclusion. I know when I started out with an inadequate understanding of what = producing power meant - I looked around for someone to ask questions of = and found no one (no fly rotary type e mail list then). Well, not = quite correct, some of the rotary racing crowd tried to help, but their = focus was completely different from mine. Not their fault, I tried to = follow/copy their approach. But, I soon realized that what works great = for the racer may really "suck" in our application. =20 Again, referring to a comment , Lynn, made about large TB having minimal = effect on the tuned length whereas the opposite is true for a small TB. = Since my tuned length is undoubtedly on the long side with 21" between = port and TB, this may be another factor why changing the TB in my case = made such a difference. =20 The nicest thing is you guys with the real experience convey it to us = for no $$ and all we have to do is listen and ask questions - even = "dumb" questions. Its really an asset to have you guys on the list. Ed Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.dmack.net/mazda/index.html =20 ----- Original Message -----=20 From: wrjjrs@aol.com=20 To: Rotary motors in aircraft=20 Sent: Wednesday, May 02, 2007 11:37 AM Subject: [FlyRotary] Re: Throttle body size/ other "Paul" issues Ed, You are RIGHT. What Lynn is refering to is that with effort, you can = tune for that if your system is sofisticated enough, and your injectors = have enough headroom. (This would require a lot of fuel, RIGHT NOW) MAP = sensor, Throttle angle sensor, and rpm sensor should allow you to tune = for rapid throttle opening, but that doesn't mean that it will be easy. = If I have a choice I err on the side of smaller rather than larger. Lynn = in in a racing application, which is a bit different. My comment is just = because you can do a thing doesn't always make it the correct choice. = Your 65mm TB is WORKING stay with it. FWIW Bill Jepson =20 -----Original Message----- From: eanderson@carolina.rr.com To: flyrotary@lancaironline.net Sent: Wed, 2 May 2007 5:30 AM Subject: [FlyRotary] Re: Throttle body size/ other "Paul" issues Humm, that very interesting, Lynn. The primary reason I removed the = 75 mm TB and reinstalled the 65mm TB was that the engine would "bog" = upon rapid opening of the throttle with the larger dia TB. If this was not caused by the large TB then I guess I'm wondering = what was causing it as the rest of the induction system was the same. = My thinking (apparently in error) was that the sudden change in = "effective" area by opening the large TB had a momentary impact on the = air velocity in the runners thereby causing the hesitation.. =20 Ed =20 ----- Original Message -----=20 From: lehanover@aol.com=20 To: Rotary motors in aircraft=20 Sent: Wednesday, May 02, 2007 1:58 AM Subject: [FlyRotary] Re: Throttle body size/ other "Paul" issues On further review, TB size should have no affect on throttle response at all in an = ijected system.=20 In our carbed engines, rapid throttle opening drops manifold = pressure to ambiant and flow through the booster venturi is not adequate = to match the fuel flow to the throttle position and the engine falls on = its face for lack of fuel. Thus the accellerator pump and jet system, = which pees a long stream of fuel into the hole while the engine winds up = enough revs (and air flow) to engage the boosters and get a fuel mist = pouring into the carb. No such drama should be required in the injected engine. Should the = TB open in less than X amount of time could not the injectors closest to = the engine stand wide open for one or two revolutions, or cycles? Or = even just some period of time longer than normal? So, it should not matter at all how big the TB is, as it is not even = required until you want to slow or shut down the engine. If there is a = butterfly in the inlet tract, the tuned length is usually figured from = that, and not the total length as from the opening into the air filter = or inlet bell. Notice the slide valve throttles on big time race = engines. No affect on the tuned length. That throttle shaft and = butterfly screws up the tune, and shortens the tuned length. On the old Formula Continental engines, stock 1600CC VW water cooled = engines with the heads and decks shaved to give huge compression with = stock parts, the injection was free. So what did the smart people use = for injection? High pressure mechanical with high pop pressure = injectors, that shot a nasty looking stream of fuel, not a nice fog of = fuel at all. The injectors were mounted in the center of long bell = shapes, and that fast moving stream of fuel was part of an ejector = system that was used to boost airflow to the tune (pun) of 175 HP from a = 54 HP VW Rabbit engine.=20 So the bigger the TB the less it should affect the tuned length, and = conversly the smaller the TB the more it should affect the tuned length. = For a reference the difference between carbed and injected engines = with a restrictor in the injected system the same size as the choke in = the carbed engine as 5 to 8 HP. This is mostly the loss of the booster = venturi in the center of the hole.=20 The improvement in a carbed engine between 36MM and 38MM chokes is = about 5 HP. Per Daryl Drummond. Race engine builder. Is this fun to think about or what? Lynn E.Hanover=20 =20 ----- Original Message -----=20 From: wrjjrs@aol.com=20 To: Rotary motors in aircraft=20 Sent: Tuesday, May 01, 2007 12:27 PM Subject: [FlyRotary] Re: Throttle body size/ other "Paul" issues Interesting Lynn, For the comparison that is 2,035 square mm inlet area. Assuming = the bigger 13B could use 1/3 More inlet area the total would be 2,646 = square mm. The inlet area of the 65 mm throttle body is 3,318 square = mm. Seems like a 65 mm TB would be more than up to the task. A 60 mm TB = is 2,827 square mm for reference. Plenty big Buly Bill Jepson =20 -----Original Message----- From: lehanover@aol.com To: flyrotary@lancaironline.net Sent: Tue, 1 May 2007 9:08 AM Subject: [FlyRotary] Re: Throttle body size/ other "Paul" issues Two 36MM chokes is enough for 244.8 HP at 9,400 RPM, and About 176 = HP at 7,000 RPM. I am in California and the dyno sheet is in Hebron = Ohio. But I can quote it when I get back if it would help anyone. Lynn E. Hanover =20 AOL.com. ------=_NextPart_000_001A_01C78CB3.D4D238D0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Thanks, Bill for pointing out the = subtle=20 differences.  I generally stay with what my aircraft/engine likes = even if I=20 don't always have an accurate understanding of what is going on.  I = don't=20 care if larger TB are "suppose" to be "better"  - if my engine = doesn't like=20 it, then I don't like it. {:>).
 
I think the real message here is that = our operating=20 regime is different from the racer and the better we understand those=20 differences the more optimum our system will be for operating=20 regime.  As yourself, Tracy, Lynn (and others have put it) = bigger is=20 not always better.  Folks like yourself and Lynn who have real = world=20  experience with the racing side (be it rotary engines or others)=20 understand this.  But for many, lacking that experience, we try to = "think"=20 our way through it - which if you don't understand the impact/influence = of all=20 the variables in all the situations (and their very complex = interaction) -=20 just might lead you to a false conclusion.
 
I know when I started out with an = inadequate=20 understanding of what producing power meant - I looked around for = someone to ask=20 questions of and found no one (no fly rotary type e mail list=20 then).  Well, not  quite correct, some of the rotary = racing crowd=20 tried to help, but their focus was completely different from mine.  = Not=20 their fault, I tried to follow/copy their approach.  But, I soon = realized=20 that what works great for the racer may really "suck"  in our=20 application. 
 
Again, referring to a comment , Lynn, = made about=20 large TB having minimal effect on the tuned length whereas the opposite = is true=20 for a small TB.  Since my tuned length is undoubtedly on the long = side with=20 21" between port and TB, this may be another factor why changing the TB = in=20 my case made such a difference. 
 
The nicest thing is you guys with the = real=20 experience convey it to us for no $$ and all we have to do is listen and = ask=20 questions - even "dumb" questions.  Its really an asset to have you = guys on=20 the list.
 
Ed
 
Ed Anderson
Rv-6A N494BW Rotary=20 Powered
Matthews, NC
eanderson@carolina.rr.comhttp:/= /members.cox.net/rogersda/rotary/configs.htm#N494BW
http://www.dmack.net/mazda= /index.html
 
 
 
 
 
 
----- Original Message -----
From:=20 wrjjrs@aol.com
Sent: Wednesday, May 02, 2007 = 11:37=20 AM
Subject: [FlyRotary] Re: = Throttle body=20 size/ other "Paul" issues

Ed,
 You are RIGHT. What Lynn is refering to is that with = effort, you=20 can tune for that if your system is sofisticated enough, and your = injectors=20 have enough headroom. (This would require a lot of fuel, RIGHT NOW) = MAP=20 sensor, Throttle angle sensor, and rpm sensor should allow you to tune = for=20 rapid throttle opening, but that doesn't mean that it will be easy. If = I have=20 a choice I err on the side of smaller rather than larger. Lynn in in a = racing=20 application, which is a bit different. My comment is just because you = can do a=20 thing doesn't always make it the correct choice. Your 65mm TB is = WORKING stay=20 with it. FWIW
Bill Jepson
 
 
-----Original Message-----
From:=20 eanderson@carolina.rr.com
To: flyrotary@lancaironline.net
Sent: = Wed, 2=20 May 2007 5:30 AM
Subject: [FlyRotary] Re: Throttle body size/ other = "Paul"=20 issues

Humm, that very interesting, Lynn.  =  The=20 primary reason I removed the 75 mm TB and reinstalled the 65mm TB was = that the=20 engine would "bog" upon rapid opening of the throttle with the larger = dia=20 TB.
 
  If this was not caused by the large TB = then I=20 guess I'm wondering what was causing it as the rest of the induction = system=20 was the same.  My thinking (apparently in error) was that the = sudden=20 change in "effective" area by opening the large TB had a = momentary impact=20 on the air velocity in the runners thereby causing the=20 hesitation..  
 
Ed 
----- Original Message -----
From:=20 lehanover@aol.com
To: Rotary motors in = aircraft=20
Sent: Wednesday, May 02, 2007 = 1:58=20 AM
Subject: [FlyRotary] Re: = Throttle body=20 size/ other "Paul" issues

On further review,

TB size should have no affect on = throttle=20 response at all in an ijected system.

In our carbed engines, = rapid=20 throttle opening drops manifold pressure to ambiant and flow through = the=20 booster venturi is not adequate to match the fuel flow to the = throttle=20 position and the engine falls on its face for lack of fuel. Thus the = accellerator pump and jet system, which pees a long stream of fuel = into the=20 hole while the engine winds up enough revs (and air flow) to engage = the=20 boosters and get a fuel mist pouring into the carb.

No such = drama=20 should be required in the injected engine. Should the TB open in = less than X=20 amount of time could not the injectors closest to the engine stand = wide open=20 for one or two revolutions, or cycles? Or even just some period of = time=20 longer than normal?

So, it should not matter at all how big = the TB=20 is, as it is not even required until you want to slow or shut down = the=20 engine. If there is a butterfly in the inlet tract, the tuned length = is=20 usually figured from that, and not the total length as from the = opening into=20 the air filter or inlet bell. Notice the slide valve throttles on = big time=20 race engines. No affect on the tuned length. That throttle shaft and = butterfly screws up the tune, and shortens the tuned = length.

On the=20 old Formula Continental engines, stock 1600CC VW water cooled = engines with=20 the heads and decks shaved to give huge compression with stock = parts, the=20 injection was free. So what did the smart people use for injection? = High=20 pressure mechanical with high pop pressure injectors, that shot a = nasty=20 looking stream of fuel, not a nice fog of fuel at all. The injectors = were=20 mounted in the center of long bell shapes, and that fast moving = stream =20 of fuel was part of an ejector system that was used to boost airflow = to the=20 tune (pun) of 175 HP from a 54 HP VW Rabbit engine.

So the = bigger=20 the TB the less it should affect the tuned length, and conversly the = smaller=20 the TB the more it should affect the tuned length.

For a = reference=20 the difference between carbed and  injected engines with a = restrictor=20 in the injected system the same size as the choke in the carbed = engine as 5=20 to 8 HP. This is mostly the loss of the booster venturi in the = center of the=20 hole.

The improvement in a carbed engine between 36MM and = 38MM=20 chokes is about 5 HP. Per Daryl Drummond. Race engine = builder.

Is=20 this fun to think about or what?

Lynn E.Hanover
 
 

 
----- = Original=20 Message -----
From:=20 wrjjrs@aol.com=20
To: = Rotary motors in = aircraft=20
Sent:=20 Tuesday, May 01, 2007 12:27 PM
Subject:=20 [FlyRotary] Re: Throttle body size/ other "Paul" issues

Interesting Lynn,
For the comparison that is 2,035 square mm inlet area. = Assuming the=20 bigger 13B could use 1/3 More inlet area the total would be 2,646 = square=20 mm. The inlet area of the 65 mm  throttle body is 3,318 = square mm.=20 Seems like a 65 mm TB would be more than up to the task. A 60 = mm TB=20 is 2,827 square mm for reference. Plenty big Buly
Bill Jepson
 
 
-----Original Message-----
From:=20 lehanover@aol.com
To:=20 flyrotary@lancaironline.net
Sent: Tue, 1 May 2007 9:08=20 AM
Subject: [FlyRotary] Re: Throttle body size/ other "Paul"=20 issues

Two 36MM chokes is enough for 244.8 HP at 9,400 RPM, and = About 176 HP=20 at 7,000 RPM. I am in California and the dyno sheet is in Hebron = Ohio. But=20 I can quote it when I get back if it would help = anyone.

Lynn E.=20 Hanover
 
 

AOL.com.
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