X-Junk-Score: 0 [] X-Cloudmark-Score: 0 [] X-Cloudmark-Analysis: v=2.2 cv=No+TSIVJ c=1 sm=1 tr=0 a=Dan8yT3GjQgZekbd7xHNVg==:117 a=IrvoUvzoI6vFScZsnRROXw==:17 a=x7bEGLp0ZPQA:10 a=A-0mRrAPPO4A:10 a=3JhidrIBZZsA:10 a=r77TgQKjGQsHNAKrUKIA:9 a=pGLkceISAAAA:8 a=Ia-xEzejAAAA:8 a=7g1VtSJxAAAA:8 a=HLElNSDFAAAA:8 a=N4BA22dSAAAA:8 a=_6GpL_ENAAAA:8 a=XnyKTCjI3CSpMaV6aQsA:9 a=QEXdDO2ut3YA:10 a=Qa1je4BO31QA:10 a=izEWSWqvyK8A:10 a=KqsoOQp8tHIA:10 a=ooph3NpzJo8A:10 a=gvSQh4r-fQ0A:10 a=4PR2P7QzAAAA:8 a=LG-zNOvVAy08ijtNIncA:9 a=2X04Ax1zPCXl22ve:21 a=_W_S_7VecoQA:10 a=Urk15JJjZg1Xo0ryW_k8:22 a=grOzbf7U_OpcSX4AJOnl:22 a=NTybjnMHmzLOwcLJc94Q:22 a=DfVtRexSPdyR86Qi2_78:22 a=4dqwQCo7Po2mVW515mGf:22 From: "Charlie England ceengland7@gmail.com" Received: from mail-yb1-f175.google.com ([209.85.219.175] verified) by logan.com (CommuniGate Pro SMTP 6.2.10) with ESMTPS id 12073640 for flyrotary@lancaironline.net; Sat, 05 Jan 2019 22:48:42 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.219.175; envelope-from=ceengland7@gmail.com Received: by mail-yb1-f175.google.com with SMTP id j10so13204273ybj.8 for ; Sat, 05 Jan 2019 19:48:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language; bh=67T6K2A5qyhhjRCRo8Rr+9eaMFdZWiXucFewzJy+860=; b=MjJfDdXow2oQN0fL5uL3vPq/c+0pLjgPron/XGNP3OwDQdNkqq/vEYaBYNCWPbhr8a IHIuTdnt/RvUb1woqNPPsz1kMKsr8tGDa8Lm1PwF84tiMb/QGrWopHfQSYaARB5etNTF pwwg6tQjciBEsu9KX4ZHk9imI7E5R+KYloyHxsetGZHwDzQ8KXDc8X9XceskPpkaW4oL VShH4qxGZAmFYnjaZhka8IsGWqMPwoXbaNyZUVksEcZMEP12Zp9xBcu9jr5/wTd/M7ru GyLwPm+pdK9vk1LTHDc2Z6SWQEUfz5/SpLa8uCODTpg7O5VGJG8VX7omMIoqShuS6jNH WGAw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language; bh=67T6K2A5qyhhjRCRo8Rr+9eaMFdZWiXucFewzJy+860=; b=HjeoWG1jCRVK0tfcHlaKPrReODMZhPW5XQWcmV6niD/0gztL5N7EdcyrL27/YB9BZ1 QdVshmv6TQdkxBSfwDQakIQ2+NULRbCrLWU0jYJ3y3gCTocrTKslO3r0NOIrBH/jKixx 4Hjkch8Nhf3LDywZmXq/KmJHri/MAS+wbzRMwiJEjJHVZoQTj8c3TB/hAdPCRn6U6GXf OtIe1pn+rcKuyR4cDtGnhp9wrYQrtsVAmYN2vxhA0707STbbx9xcB6Wkj6J2+xpsKCtt 0zWr0iv5YtoBQTQT8t01w+3v2J4SAI2gH+rz9guL54JyH8iSb07mjHABjJ8fKSFYESWI Rp6Q== X-Gm-Message-State: AJcUukf+jlQj0NpI7P4bBPKVIps9EqKFhUBzkIez0DPYSRRJQXvLLp/Z g5ypW0GUspAMqxGSBa9Ba4aquQ5b X-Google-Smtp-Source: ALg8bN7Gjlq+N1aqCV+j322CkoHMJUmoEWGK+F6oFGgvSC6QRpybtJbo/A5PuEzVoLLhLidRokPlHw== X-Received: by 2002:a25:ef47:: with SMTP id w7mr41403179ybm.50.1546746506854; Sat, 05 Jan 2019 19:48:26 -0800 (PST) Return-Path: Received: from [192.168.10.217] (mobile-166-177-186-115.mycingular.net. [166.177.186.115]) by smtp.googlemail.com with ESMTPSA id w1sm22724670ywd.49.2019.01.05.19.48.25 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 05 Jan 2019 19:48:26 -0800 (PST) Subject: Re: [FlyRotary] Exhaust setup's To: Rotary motors in aircraft References: Message-ID: Date: Sat, 5 Jan 2019 21:51:18 -0600 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.3.3 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/alternative; boundary="------------8D2C35A8F121D986E10E4511" Content-Language: en-US X-Antivirus: Avast (VPS 190105-4, 01/05/2019), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. --------------8D2C35A8F121D986E10E4511 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit On 1/5/2019 11:32 AM, Matt Boiteau mattboiteau@gmail.com wrote: > *Anybody have advice on how they run their exhaust exit systems?* > > - Matt Boiteau > > ------ Forwarded Message -------- > From: Matt Boiteau mattboiteau@gmail.com > Date: 12/9/2018 10:13:56 PM > Subject: [FlyRotary] Exhaust setup's > To: Rotary motors in aircraft > > I'm at the stage of securing an exhaust setup. How do you guys do it? > > I'll have a sub-cowl under the belly of the plane (shape of a tear > drop), which will streamline the main cowl air (coolant and oil outlets). > > I'm thinking I exit the exhaust (2.5" pipe) inside the sub-cowl and > have a 5" wrapped around it which ends out the sub-cowl for x length. > This should help create a vacuum and pump out the main cowl air. > > Before exiting the main exhaust pipe, should I have perforated holes > or louvers in it? > > > - Matt Boiteau > -- Homepage: http://www.flyrotary.com/ Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > Hi Matt, I'm no engineer, but I do know a few engineers with recent hotel time. :-) Have you read this thread? http://www.vansairforce.com/community/showthread.php?t=68241&highlight=cowl This is a later thread, with postings & references back to the link above: http://www.vansairforce.com/community/showthread.php?t=159473&highlight=cowl Watch Onewinglo's youtube video & try to visualize what the air's doing wrong as it comes out of the cowl. It's about cooling a Lyc, but cooling is cooling. It's a long thread, but reading anything posted by DanH is worthy of respect. Note all the attention to smoothly curved entry areas, and the ultimate 'bluff body' (squared off) exit, with the external surfaces parallel to the free stream around the a/c. I could be wrong, but I see a lot of skin drag with the tube-in-a-tube, with the exit air having to scrub on both tubes to get out. Also a *lot* of drag where the cooling outlet air enters the outer tube (reference: 'bellmouth' & 'velocity stack'). Is the perforated inner tube intended to be a muffler? If so, it's kinda like  the inner tube of a Spintech muffler, but the dimpled slots face aft in the Spintech. The spintech works great as a rotary muffler, if that's your goal. There's lots of NACA & NASA research on eductors, if you do a little digging. Most of the stuff I've seen says that they can work great at low speeds, at the expense of excess cooling drag in cruise. A good storehouse of reading material is the CAFE Foundation. Try here: https://cafe.foundation/v2/tech_enablingtech_dragreduction.php and here: https://cafe.foundation/v2/research_reports.php with attention to the three 'Local Flow' articles in the 2nd link. Here's hoping I'm not making things worse, Charlie --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus --------------8D2C35A8F121D986E10E4511 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 8bit
On 1/5/2019 11:32 AM, Matt Boiteau mattboiteau@gmail.com wrote:
*Anybody have advice on how they run their exhaust exit systems?*

- Matt Boiteau

------ Forwarded Message --------
From: Matt Boiteau mattboiteau@gmail.com <flyrotary@lancaironline.net>
Date: 12/9/2018 10:13:56 PM
Subject: [FlyRotary] Exhaust setup's
To: Rotary motors in aircraft <flyrotary@lancaironline.net>

I'm at the stage of securing an exhaust setup. How do you guys do it?

I'll have a sub-cowl under the belly of the plane (shape of a tear drop), which will streamline the main cowl air (coolant and oil outlets).

I'm thinking I exit the exhaust (2.5" pipe) inside the sub-cowl and have a 5" wrapped around it which ends out the sub-cowl for x length. This should help create a vacuum and pump out the main cowl air.

Before exiting the main exhaust pipe, should I have perforated holes or louvers in it?


- Matt Boiteau
-- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html

Hi Matt,

I'm no engineer, but I do know a few engineers with recent hotel time. :-)

Have you read this thread?
http://www.vansairforce.com/community/showthread.php?t=68241&highlight=cowl

This is a later thread, with postings & references back to the link above:
http://www.vansairforce.com/community/showthread.php?t=159473&highlight=cowl
Watch Onewinglo's youtube video & try to visualize what the air's doing wrong as it comes out of the cowl.

It's about cooling a Lyc, but cooling is cooling. It's a long thread, but reading anything posted by DanH is worthy of respect. Note all the attention to smoothly curved entry areas, and the ultimate 'bluff body' (squared off) exit, with the external surfaces parallel to the free stream around the a/c.

I could be wrong, but I see a lot of skin drag with the tube-in-a-tube, with the exit air having to scrub on both tubes to get out. Also a *lot* of drag where the cooling outlet air enters the outer tube (reference: 'bellmouth' & 'velocity stack'). Is the perforated inner tube intended to be a muffler? If so, it's kinda like  the inner tube of a Spintech muffler, but the dimpled slots face aft in the Spintech. The spintech works great as a rotary muffler, if that's your goal.

There's lots of NACA & NASA research on eductors, if you do a little digging. Most of the stuff I've seen says that they can work great at low speeds, at the expense of excess cooling drag in cruise. A good storehouse of reading material is the CAFE Foundation. Try here:
https://cafe.foundation/v2/tech_enablingtech_dragreduction.php
and here:
https://cafe.foundation/v2/research_reports.php
with attention to the three 'Local Flow' articles in the 2nd link.

Here's hoping I'm not making things worse,

Charlie


Avast logo

This email has been checked for viruses by Avast antivirus software.
www.avast.com


--------------8D2C35A8F121D986E10E4511--