X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 15 Dec 2008 19:52:14 -0500 Message-ID: X-Original-Return-Path: Received: from smtp-ext-02.mx.pitdc1.expedient.net ([206.210.69.142] verified) by logan.com (CommuniGate Pro SMTP 5.2.10) with ESMTPS id 3360671 for lml@lancaironline.net; Sun, 14 Dec 2008 10:41:23 -0500 Received-SPF: none receiver=logan.com; client-ip=206.210.69.142; envelope-from=rpastusek@htii.com Received: from dlhtpax009 (static-71-178-198-10.washdc.fios.verizon.net [71.178.198.10]) by smtp-ext-02.mx.pitdc1.expedient.net (Postfix) with ESMTPA id 0550D7C78E for ; Sun, 14 Dec 2008 10:40:47 -0500 (EST) Reply-To: From: "Robert Pastusek" X-Original-To: "'Lancair Mailing List'" References: In-Reply-To: Subject: RE: [LML] Re: Cabin heat LNC4 X-Original-Date: Sun, 14 Dec 2008 10:40:42 -0500 Organization: Holmes-Tucker International, Inc. X-Original-Message-ID: <096401c95e02$530fa6d0$f92ef470$@com> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0965_01C95DD8.6A399ED0" X-Mailer: Microsoft Office Outlook 12.0 Thread-Index: AcldoGxOaMuiYMVcSzSaZZuVX9ciuAAXeUNA Content-Language: en-us This is a multipart message in MIME format. ------=_NextPart_000_0965_01C95DD8.6A399ED0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Tim wrote: Are there Sonics in the Cold side of the intercooler? I don't think so.. Does the longer length of the hoses and the 3rd intercooler reduce flow/pressure ? You are correct on not using sonic nozzles on the cold side of the intercooler. The exit air is much cooler, and therefore under much less pressure (recall Boyle's Law), so full flow through the cold side tubes helps achieve a balanced flow between hot and cold temperature selection in the cockpit. Not the "scientific" way to achieve a flow balance, but it's very simple and works pretty well-over the flow rates and pressures we're using. And to answer your second question, the pressure and flow are not affected so much by the hose length and long flow path-which do contribute somewhat. The drop in temperature is responsible for the majority of reduced pressure/flow through the cold side. To answer another question posed by an LML contributor: the concept of a "sonic" nozzle is that when the air passing through the nozzle reaches supersonic flow, it sets up a shock wave in the throat that effectively "throttles" the flow. This causes the nozzle to flow a relatively constant volume of air over a wide range of input pressure-once the flow reaches supersonic in the throat. Without these, you'd see a very abrupt change in cabin in-flow and pressure every time you move the throttle of your turbocharged Continental while the cabin pressure controller-a rather slow-acting device, struggles to keep up with the changes. If you install the sonic nozzles backward, they won't work as intended, the flow will be closely proportional to the input pressure. Hope this helps. Bob Pastusek ------=_NextPart_000_0965_01C95DD8.6A399ED0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Tim wrote:

 

Are there Sonics in the Cold side of the intercooler?  = I don’t think so..  Does the longer length of the hoses and the = 3rd intercooler reduce flow/pressure ?

 

You are correct on not using sonic nozzles on the cold side of the = intercooler. The exit air is much cooler, and therefore under much less pressure (recall = Boyle’s Law), so full flow through the cold side tubes helps achieve a balanced = flow between hot and cold temperature selection in the cockpit. Not the = “scientific” way to achieve a flow balance, but it’s very simple and works = pretty well—over the flow rates and pressures we’re using. And to answer your = second question, the pressure and flow are not affected so much by the hose = length and long flow path—which do contribute somewhat. The drop in = temperature is responsible for the majority of reduced pressure/flow through the cold = side.

To answer another question posed by an LML contributor: the concept of a = “sonic” nozzle is that when the air passing through the nozzle reaches = supersonic flow, it sets up a shock wave in the throat that effectively = “throttles” the flow. This causes the nozzle to flow a relatively constant volume of = air over a wide range of input pressure-once the flow reaches supersonic in = the throat. Without these, you’d see a very abrupt change in cabin = in-flow and pressure every time you move the throttle of your turbocharged = Continental while the cabin pressure controller—a rather slow-acting device, = struggles to keep up with the changes. If you install the sonic nozzles backward, = they won’t work as intended, the flow will be closely proportional to = the input pressure.

Hope this = helps.

Bob = Pastusek

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