X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: <13brv3@bellsouth.net> Received: from imf19aec.mail.bellsouth.net ([205.152.59.67] verified) by logan.com (CommuniGate Pro SMTP 4.3c5) with ESMTP id 932159 for flyrotary@lancaironline.net; Wed, 04 May 2005 09:23:28 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.152.59.67; envelope-from=13brv3@bellsouth.net Received: from rd ([65.6.194.9]) by imf19aec.mail.bellsouth.net (InterMail vM.5.01.06.11 201-253-122-130-111-20040605) with ESMTP id <20050504132242.HBCZ2470.imf19aec.mail.bellsouth.net@rd> for ; Wed, 4 May 2005 09:22:42 -0400 From: "Russell Duffy" <13brv3@bellsouth.net> To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Static MAP readings? Date: Wed, 4 May 2005 08:22:56 -0500 Message-ID: <040301c550ac$6262b440$6101a8c0@rd> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0404_01C55082.798CAC40" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2527 In-Reply-To: This is a multi-part message in MIME format. ------=_NextPart_000_0404_01C55082.798CAC40 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable 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 =20 Hi Al, Yes, I recall that we've had this conversation before :-) =20 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 =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 =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 =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 =20 Whatever that MAP reading is, I don't think that there is a significant power penalty that goes with it.=20 =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 =20 Hoping this makes you feel better,=20 =20 I'm afraid not, just the opposite in fact, but thanks for trying :-) =20 Cheers, Rusty (dealing with the Ebay single rotor guy)=20 ------=_NextPart_000_0404_01C55082.798CAC40 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message
Yes.  = As you may=20 recall, I also run with the TWM TB, and I also see lower MAP than the = local=20 atmospheric pressure.  That is quite likely as it should be, or if = not; it=20 doesn’t matter.  The MAP reading depends on where you measure = it.   
 
Hi=20 Al,   Yes, I recall that we've had this conversation before=20 :-)
 
I = certainly agree=20 that it matters where you measure the MAP, and it would be nice if we = were all=20 measuring it in the same place for comparison.  I'm thinking = of trying=20 to put a port at the intake flange, but I'm not sure if I have room to = drill and=20 tap a hole there yet.  I'm also not sure it will give an accurate=20 reading.  Still, it won't give an apples to apples comparison to = anyone=20 else.     
 
On the dyno = at WOT at=20 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 of=20 just over 80) with 9.0 rotors.  At 7000 rpm the MAP reading was = 23.5” and=20 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.  = Velocity=20 makes up for some of this, but I'm not sure where the tradeoff=20 is.   If you've got=20 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 = don't you=20 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 you=20 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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