Return-Path: Received: from ms-smtp-02.southeast.rr.com ([24.93.67.83] verified) by logan.com (CommuniGate Pro SMTP 4.1.3) with ESMTP id 2584594 for flyrotary@lancaironline.net; Thu, 18 Sep 2003 14:24:29 -0400 Received: from o7y6b5 (clt78-020.carolina.rr.com [24.93.78.20]) by ms-smtp-02.southeast.rr.com (8.12.5/8.12.2) with SMTP id h8IIKepN021548 for ; Thu, 18 Sep 2003 14:20:40 -0400 (EDT) Message-ID: <007d01c37e11$cd6073a0$1702a8c0@WorkGroup> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Whats good for Racing is necessarily good for aircraft was Re: Intake questions Date: Thu, 18 Sep 2003 14:22:21 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_007A_01C37DF0.4614D7E0" 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_007A_01C37DF0.4614D7E0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message From: Russell Duffy=20 To: Rotary motors in aircraft=20 Sent: Wednesday, September 17, 2003 11:01 AM 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 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 Hi, Rusty.....I purchased the short intake manifold from Dave = Atkins. He claims he has more than adequate power with his, and that = idle is also good. Look at all the race cars and racing motorcycles = that have the carbs or throttle bodies right next to the engine. They = seem to generate a lot of power that way. For what it's worth. Paul Conner Paul is correct. There are any number of intake configurations that = will produce adequate power for the RV-6. I am told that Dave Atkin's = intake permits him to generate approx 160HP which is certainly adequate = for an RV and could even provide thrilling performance in a low weight = RV I'll have to say I've flow an RV with adequate (whatever that means) = performance while producing as little as 120HP. The cruise was around = 180 TAS which was adequate because even today I generally elected to = cruise at 170 TAS to conserve fuel, but take off and climb with 120 HP = in my somewhat heavy bird were agony! Paul, not disputing what you say at all, but you have to consider = the different application. you are making the same assumption that I = made with my first intake. Yes, I listened to the Racing guys and I'm = certain that their advice was just peachy for racing - if you are = turning over 7000-8000 rpm. Than rpm range means short runners and = large diameter inlets are the cats meaow. =20 But, I can tell you from personal experience that if you think you = are going to put a curise prop on your RV-6 with that set up and think = you are going to turn 7000-8000 rpm with a 2.17:1 PSRU you are going to = be sadly disappointed. Tracy Crook turns as high an RPM with that set up = as anyone I know (has hit 214 mph TAS) and maxs out at around 6400 rpm. = His tubes are 1.25 and 1.5" in diameter as best I recall and wrap over = the top of his engine so that is air intake sits on the top middle of = his cowl. So the tubes are not short. =20 The auto and motor cycle guys have one advantage - they have gear = boxes which permit them to wind the engine up into those higher rpm = ranges with a lighter load (lower gear) before shifting to the next = ratio (where you do indeed generate more power), but we can't wind our = engine and then shift gears (at least not yet). Bill Eslick initially use a very short induction system which = provided very disappointing performance results. His report (earlier on = the list this week) indicates that once he went with a different (read - = longer intake, copied after Tracy's as was mine) his performance = improved so that he now keeps up with the 160 HP Lycoming powered RV-6s. = You have to select the induction system parameters that is realistic = for your application! What sucks for us - works for the race guys, what = works for us -would suck for the race guys. Its like apples and oranges = (so to speak) {:>) Now, I will be the first to say, if you want to experiment or if you = find for cost, configuration or convience reasons you want to try some = particular intake configuration, please do so. I've been wrong before = and I am certain will be in the future - but, do it with your eyes open = and understanding of what performance might reasonably be expected. Best Regards Ed Anderon ------=_NextPart_000_007A_01C37DF0.4614D7E0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
 
From:=20 Russell=20 Duffy
To: Rotary motors in = aircraft=20
Sent: Wednesday, September = 17, 2003=20 11:01 AM
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 :-) 
 power band, so I started wondering if I = could=20 "tune" it with individual pipes on the inlet side of the=20 TB.  
 
Thanks,
Rusty = (Scotty, I need=20 more power!) 
 
Hi, = Rusty.....I=20 purchased the short intake manifold from Dave Atkins. He claims he = has more=20 than adequate power with his, and that idle is also good.  Look = at all=20 the race cars and racing motorcycles that have the carbs or throttle = bodies=20 right next to the engine.  They seem to generate a lot of power = that=20 way. For what it's worth.
 
 Paul=20 Conner
 
 
 
Paul is = correct. There=20 are any number of intake configurations that will produce adequate = power for=20 the RV-6. I am told that Dave Atkin's intake permits him to = generate=20 approx 160HP which is certainly adequate for an RV and could even = provide=20 thrilling performance in a low weight RV
 
I'll have = to=20 say I've flow an RV with adequate (whatever that means)=20 performance while producing as little as 120HP.  The = cruise=20 was around 180 TAS which was adequate because even today I = generally=20 elected to cruise at 170 TAS to conserve fuel, but take off and = climb with=20 120 HP in my somewhat heavy bird were agony!
 
 Paul, = not=20 disputing what you say at all, but you have to consider the = different=20 application.  you are making the same assumption that =  I made=20 with my first intake.  Yes, I listened to the Racing guys and = I'm=20 certain that their advice was just peachy for racing - if you are = turning=20 over 7000-8000 rpm.  Than rpm range means short runners and = large=20 diameter inlets are the cats meaow. 
 
But, I can = tell you=20 from personal experience that if you think you are going to put a = curise=20 prop on your RV-6 with that set up and think you are going to turn = 7000-8000=20 rpm with a 2.17:1 PSRU you are going to be sadly = disappointed. Tracy=20 Crook turns as high an RPM with that set up as anyone I know (has = hit 214=20 mph TAS) and maxs out at around 6400 rpm.  His tubes are 1.25 = and 1.5"=20 in diameter as best I recall and wrap over the top of his engine so = that is=20 air intake sits on the top middle of his cowl.  So the tubes = are not=20 short.  
 
 The = auto and=20 motor cycle guys have one advantage - they have gear boxes which = permit them=20 to wind the engine up into those higher rpm ranges with a lighter = load=20 (lower gear) before shifting to the next ratio (where you do indeed = generate=20 more power), but we can't wind our engine and then shift gears (at = least not=20 yet).
 
Bill Eslick = initially=20 use a very short induction system which provided very disappointing=20 performance results.  His report (earlier on the list this = week) indicates that once he went with a different (read - = longer=20 intake, copied after Tracy's as was mine) his performance improved = so that=20 he now keeps up with the 160 HP Lycoming powered RV-6s.=20
 
You have to = select the=20 induction system parameters that is realistic for your=20 application!  What sucks for us - works for the race guys, what = works=20 for us -would suck for the race guys.  Its like apples and = oranges (so=20 to speak) {:>)
 
Now, I will = be the=20 first to say, if you want to experiment or if you find for cost,=20 configuration or convience reasons you want to try some particular = intake=20 configuration, please do so.  I've been wrong before and I am = certain=20 will be in the future - but, do it with your eyes open and = understanding of=20 what performance might reasonably be expected.
 
Best=20 Regards
 
Ed=20 Anderon
 
 
 
 
 
 
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