X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 2 [X] 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 2021213 for flyrotary@lancaironline.net; Wed, 02 May 2007 08:30:40 -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 l42CTRSY006305 for ; Wed, 2 May 2007 08:29:28 -0400 (EDT) Message-ID: <001301c78cb5$b3260110$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 08:30:42 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0010_01C78C94.2BC0E9E0" 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_0010_01C78C94.2BC0E9E0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable 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_0010_01C78C94.2BC0E9E0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Humm, that very interesting, Lynn.  =  The primary=20 reason I removed the 75 mm TB and reinstalled the 65mm TB was that the = engine=20 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 guess=20 I'm wondering what was causing it as the rest of the induction system = was the=20 same.  My thinking (apparently in error) was that the sudden change = in=20 "effective" area by opening the large TB had a momentary impact on = the air=20 velocity in the runners thereby causing the=20 hesitation..  
 
Ed 
----- Original Message -----
From:=20 lehanover@aol.com
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 = position and the engine falls on its face for lack of fuel. Thus the=20 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 longer=20 than normal?

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

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

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

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

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

Is this fun to think about or what?

Lynn = E.Hanover
 
 

 
----- = Original Message=20 -----
From:=20 wrjjrs@aol.com=20
To: = Rotary motors in = aircraft=20
Sent: = Tuesday,=20 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 mm.=20 The inlet area of the 65 mm  throttle body is 3,318 square mm. = Seems=20 like a 65 mm TB would be more than up to the task. A 60 mm TB = is 2,827=20 square mm for reference. Plenty big Buly
Bill Jepson
 
 
-----Original Message-----
From: lehanover@aol.com
To:=20 flyrotary@lancaironline.net
Sent:=20 Tue, 1 May 2007 9:08 AM
Subject: [FlyRotary] Re: Throttle body = size/=20 other "Paul" 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 I=20 can quote it when I get back if it would help anyone.

Lynn E. = Hanover
 
 

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