X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from email2k3.itlnet.net ([64.19.112.12] verified) by logan.com (CommuniGate Pro SMTP 4.3c5) with ESMTP id 933565 for flyrotary@lancaironline.net; Thu, 05 May 2005 12:37:07 -0400 Received-SPF: none receiver=logan.com; client-ip=64.19.112.12; envelope-from=jwvoto@itlnet.net Received: from rav.itlnet.net (unverified [192.168.10.149]) by itlnet.net (Rockliffe SMTPRA 6.1.17) with SMTP id for ; Thu, 5 May 2005 11:36:26 -0500 Received: from JWVOTO (unverified [64.19.116.77]) by itlnet.net (Rockliffe SMTPRA 6.1.17) with SMTP id for ; Thu, 5 May 2005 11:36:24 -0500 Message-ID: <013d01c55190$d1619160$9a731340@JWVOTO> From: "Wendell Voto" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Static MAP readings? Date: Thu, 5 May 2005 08:47:49 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0094_01C5514F.1DDFCE40" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4133.2400 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4133.2400 This is a multi-part message in MIME format. ------=_NextPart_000_0094_01C5514F.1DDFCE40 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MessageWhat is the TWM throttle body? Any pictures? Wendell Yes. As you may recall, I also run with the TWM TB, and I also see = lower MAP than the local atmospheric pressure. That is quite likely as = it should be, or if not; it doesn't matter. The MAP reading depends on = where you measure it. =20 Hi Al, Yes, I recall that we've had this conversation before :-) I certainly agree that it matters where you measure the MAP, and it = would be nice if we were all measuring it in the same place for = comparison. I'm thinking of trying to put a port at the intake flange, = but I'm not sure if I have room to drill and tap a hole there yet. I'm = also not sure it will give an accurate reading. Still, it won't give an = apples to apples comparison to anyone else. =20 On the dyno at WOT at 5300 rpm with a local barometric pressure of = 29.5", the MAP reading was 27.5". At 6000 rpm, WOT, MAP had dropped to = about 26.5", and it was putting out close to 85 hp/rotor (SAE corrected, = which means actual measured of just over 80) with 9.0 rotors. At 7000 = rpm the MAP reading was 23.5" and the power was still climbing at 95 = hp/rotor. =20 Reading these numbers sounds like the definition of "restriction" to = me. The more air you try to pull through the TB, the lower the pressure = drops. Velocity makes up for some of this, but I'm not sure where the = tradeoff is. If you've got 95 hp/rotor now, imagine what it could be = with less restriction. =20 Didn't Lynn say they have to run chokes, or restrictor plates per the = rules of their racing class? He's producing lots of power, but don't = you think he'd love to take those restrictors out :-)=20 Whatever that MAP reading is, I don't think that there is a = significant power penalty that goes with it.=20 Sorry, but I can't see how you can say this. It seems to me that MAP = is probably the number one factor in power production. =20 Hoping this makes you feel better,=20 I'm afraid not, just the opposite in fact, but thanks for trying :-) Cheers, Rusty (dealing with the Ebay single rotor guy)=20 ------=_NextPart_000_0094_01C5514F.1DDFCE40 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
What is the TWM throttle body? Any pictures?
Wendell
Yes.  As you=20 may recall, I also run with the TWM TB, and I also see lower MAP than = the=20 local atmospheric pressure.  That is quite likely as it should = be, or if=20 not; it doesn’t matter.  The MAP reading depends on where = you measure=20 it.   
 
Hi=20 Al,   Yes, I recall that we've had this conversation before=20 :-)
 
I certainly=20 agree that it matters where you measure the MAP, and it would be nice = if we=20 were all measuring it in the same place for comparison.  I'm = thinking of trying to put a port at the intake flange, but I'm not = sure if I=20 have room to drill and tap a hole there yet.  I'm also not sure = it will=20 give an accurate reading.  Still, it won't give an apples to = apples=20 comparison to anyone else. =20    
 
On the = dyno at WOT=20 at 5300 rpm with a local barometric pressure of 29.5”, the MAP = reading was=20 27.5”.  At 6000 rpm, WOT, MAP had dropped to about = 26.5”, and it was=20 putting out close to 85 hp/rotor (SAE corrected, which means actual = measured=20 of just over 80) with 9.0 rotors.  At 7000 rpm the MAP reading = was 23.5”=20 and the power was still climbing at 95 hp/rotor.   
 
Reading these=20 numbers sounds like the definition of "restriction" to me.  = The more=20 air you try to pull through the TB, the lower the pressure = drops. =20 Velocity makes up for some of this, but I'm not sure where the = tradeoff=20 is.   If you've=20 got 95 hp/rotor now, imagine what it could be with less=20 restriction.  
 
Didn't Lynn say=20 they have to run chokes, or restrictor plates per the = rules of=20 their racing class?  He's producing lots of power, but=20 don't you think he'd love to take those restrictors out=20 :-) 
 
Whatever = that MAP=20 reading is, I don’t think that there is a significant power = penalty that goes=20 with it. 
 
Sorry, but I=20 can't see how you can say this.  It seems to me that MAP is = probably=20 the number one factor in power production.=20  

 

Hoping = this makes=20 you feel better, 

 

I'm afraid not,=20 just the opposite in fact, but thanks for trying=20 :-)

 

Cheers,

Rusty (dealing=20 with the Ebay single rotor=20 = guy) 

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