X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fmailhost06.isp.att.net ([204.127.217.106] verified) by logan.com (CommuniGate Pro SMTP 5.4c3j) with ESMTP id 4960460 for flyrotary@lancaironline.net; Thu, 28 Apr 2011 09:42:24 -0400 Received-SPF: none receiver=logan.com; client-ip=204.127.217.106; envelope-from=bbradburry@bellsouth.net Received: from desktop (adsl-85-145-79.mco.bellsouth.net[98.85.145.79]) by isp.att.net (frfwmhc06) with SMTP id <20110428134147H0600e7hmee>; Thu, 28 Apr 2011 13:41:47 +0000 X-Originating-IP: [98.85.145.79] From: "Bill Bradburry" To: "'Rotary motors in aircraft'" References: In-Reply-To: Subject: RE: [FlyRotary] Re: Cooling Inlets Date: Thu, 28 Apr 2011 09:42:42 -0400 Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0009_01CC0588.9F88DE20" X-Mailer: Microsoft Office Outlook 11 Thread-Index: AcwFpV+vlZ7LVTEOTB6FGBqQPO1KjQABHD4g X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6001.18049 This is a multi-part message in MIME format. ------=_NextPart_000_0009_01CC0588.9F88DE20 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Tracy, Wow! That is less than 40 sq in of inlet area! Total!! How much exit area do you have? You mentioned a pressure sensor. What pressures are you seeing at wherever you measure it? Bill B _____ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Tracy Sent: Thursday, April 28, 2011 9:08 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Cooling Inlets Finally got around to finishing my cooling inlets. (pictures attached) Up until now they were simply round pipes sticking out of the cowl. The pipes are still there but they have properly shaped bellmouths on them. The shape and contours were derived from a NASA contractor report (NASA_CR3485) that you can find via Google. Lots of math & formulas in it but I just copied the best performing inlet picture of the contour. Apparently there is an optimum radius for the inner and outer lip of the inlet. There was no change to the inlet diameters of 5.25" on water cooler and 4.75" on oil cooler. The simple pipes performed adequately in level flight at moderate cruise settings even on hot days but oil temps would quickly hit redline at high power level flight and in climb. The significant change with the new inlet shape is that they appear to capture off-axis air flow (like in climb and swirling flow induced by prop at high power) MUCH better than the simple pipes. First flight test was on a 94 deg. F day and I could not get the oil temp above 200 degrees in a max power climb. They may have gone higher if the air temperature remained constant but at 3500 fpm the rapidly decreasing OAT kept the temps well under redline (210 deg F). I have an air pressure instrument reading the pressure in front of the oil cooler and was amazed at the pressure recovered from the prop wash. At 130 MPH the pressure would almost double when the throttle was advanced to WOT. That did not happen nearly as much with the simple pipes. These inlets ROCK! Tracy Crook ------=_NextPart_000_0009_01CC0588.9F88DE20 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Tracy,

 

Wow!  That is less than 40 sq = in of inlet area!  Total!!  How much exit area do you = have?

 

You mentioned a pressure = sensor.  What pressures are you seeing at wherever you measure it?

 

Bill B

 

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Tracy
Sent: Thursday, April 28, = 2011 9:08 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: = Cooling Inlets

 

Finally got around to finishing my cooling inlets. (pictures attached)  Up = until now they were simply round pipes sticking out of the cowl.   = The pipes are still there but they have properly shaped bellmouths on them.   The shape and contours were derived from a NASA = contractor report (NASA_CR3485) that you can find via Google.  Lots of math = & formulas in it but I just copied the best performing inlet picture of = the contour.   Apparently there is an optimum radius for the inner = and outer lip of the inlet.   There was no change to the inlet = diameters of 5.25" on water cooler and 4.75" on oil cooler.

The simple pipes performed adequately in level flight at moderate cruise settings even on hot days but oil temps would quickly hit redline at = high power level flight and in climb. 

The significant change with the new inlet shape is that they appear to = capture off-axis air flow  (like in climb and swirling flow  induced = by prop at high power)  MUCH better than the simple pipes.    = First flight test was on a 94 deg. F day and I could not get the oil temp = above 200 degrees in a max power climb.    They may have gone higher if = the air temperature remained constant but at 3500 fpm the rapidly decreasing OAT = kept the temps well under redline (210 deg F).

I have an air pressure instrument reading the pressure in front of the = oil cooler and was amazed at the pressure recovered from the prop = wash.  At 130 MPH the pressure would almost double when the throttle was advanced = to WOT.   That did not happen nearly as much with the simple = pipes.  

These inlets ROCK!

Tracy Crook

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