X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from web81009.mail.yahoo.com ([206.190.37.154] verified) by logan.com (CommuniGate Pro SMTP 4.3c5) with SMTP id 931126 for flyrotary@lancaironline.net; Tue, 03 May 2005 12:59:43 -0400 Received-SPF: none receiver=logan.com; client-ip=206.190.37.154; envelope-from=deltaflyer@prodigy.net Message-ID: <20050503165857.753.qmail@web81009.mail.yahoo.com> Received: from [199.231.49.128] by web81009.mail.yahoo.com via HTTP; Tue, 03 May 2005 09:58:57 PDT Date: Tue, 3 May 2005 09:58:57 -0700 (PDT) From: James Maher Subject: Re: [FlyRotary] Static MAP readings? To: Rotary motors in aircraft In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-488868950-1115139537=:520" --0-488868950-1115139537=:520 Content-Type: text/plain; charset=us-ascii I'm not sure that the absolute MAP numbers that you quoted are of any value. What is important IMO is the difference between the atmospheric pressure and the MAP. I am shooting for the same value for atmospheric and MAP. Anything lower would indicate a restriction. For instance when I see 29.xx WOT on a day when the atmospheric is 30.00 then I know an improvement can be made. What was the MAP reading before starting the engine? Obviously with RAM air or turbo you could go above atmospheric. That is my limited understanding. If anyone has a better understanding please elaborate. Jim Russell Duffy <13brv3@bellsouth.net> wrote: Greetings, I'm still a bit concerned about the static MAP readings that I'm getting. This isn't something that just happened, but rather has been going on for at least the life of this particular intake setup. At on point, I was almost convinced that the TWM TB ports were just not providing an accurate reading, but now I'm almost convinced that they are. Has anyone measured MAP at WOT static? I got the following results in a few tests the other day: 1- 27.6" This was with my normal configuration, which is an inlet inside the radiator duct, feeding a 3" SCEET hose, to a fiberglass duct that covers the two barrels of a TWM TB. 2- 26.3"-27.0" (erratic probably due to prop blast across the inlet) This was with the SCEET hose removed from the TB fiberglass duct. 3- 27.4" This is with a fairly small K&N cone filter on the inlet to the TB duct where the SCEET hose normally goes. From this, I see that the K&N filter seem to have no significant effect on the MAP, which is good, though I still don't know if I can fit it in there. I've got some numbers from Ed, and also have an idea what Tracy runs, but those have always been in-flight, WOT, low level runs. I'm going to try that at about 1000 ft at some point, but would also like to know what folks run static. Anyone got any readings? Thanks, Rusty (not willing to give away free power) --0-488868950-1115139537=:520 Content-Type: text/html; charset=us-ascii

I'm not sure that the absolute MAP numbers that you quoted are of any value. What is important IMO is the difference between the atmospheric pressure and the MAP. I am shooting for the same value for atmospheric and MAP. Anything lower would indicate a restriction. For instance when I see 29.xx WOT on a day when the atmospheric is 30.00 then I know an improvement can be made. What was the MAP reading before starting the engine? Obviously with RAM air or turbo you could go above atmospheric.

That is my limited understanding.

If anyone has a better understanding please elaborate.

Jim

Russell Duffy <13brv3@bellsouth.net> wrote:

Greetings,

I'm still a bit concerned about the static MAP readings that I'm getting.   This isn't something that just happened, but rather has been going on for at least the life of this particular intake setup. At on point, I was almost convinced that the TWM TB ports were just not providing an accurate reading, but now I'm almost convinced that they are. Has anyone measured MAP at WOT static?

I got the following results in a few tests the other day:

1- 27.6"   This was with my normal configuration, which is an inlet inside the radiator duct, feeding a 3" SCEET hose, to a fiberglass duct that covers the two barrels of a TWM TB.

2- 26.3"-27.0" (erratic probably due to prop blast across the inlet)   This was with the SCEET hose removed from the TB fiberglass duct.

3- 27.4"    This is with a fairly small K&N cone filter on the inlet to the TB duct where the SCEET hose normally goes.

From this, I see that the K&N filter seem to have no significant effect on the MAP, which is good, though I still don't know if I can fit it in there.

I've got some numbers from Ed, and also have an idea what Tracy runs, but those have always been in-flight, WOT, low level runs. I'm going to try that at about 1000 ft at some point, but would also like to know what folks run static. Anyone got any readings?

Thanks,

Rusty (not willing to give away free power)

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