X-CGP-ClamAV-Result: CLEAN X-VirusScanner: Niversoft's CGPClamav Helper v1.23.0 (ClamAV engine v0.103.0) X-Junk-Score: 0 [] X-KAS-Score: 0 [] From: " 12348ung@gmail.com" Received: from mail-pl1-f170.google.com ([209.85.214.170] verified) by logan.com (CommuniGate Pro SMTP 6.3.5) with ESMTPS id 154339 for flyrotary@lancaironline.net; Tue, 20 Jul 2021 18:01:52 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.214.170; envelope-from=12348ung@gmail.com Received: by mail-pl1-f170.google.com with SMTP id n11so12115914plc.2 for ; Tue, 20 Jul 2021 15:01:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:references:in-reply-to:subject:date:message-id:mime-version :thread-index:content-language; bh=XdVVjlQaDzXcvkg3eAjgyCIk0ErHgTJplyH6MlxEyE0=; b=V8kOa+c2u88L31BiewtKL7EzkyTC/DDgZ0zh0so6eCB6hT4f3MWIZi91pxKOrfDluZ VYoUUFxXjnwgCxRNs8/iMKFPTDDLbQk4NLqHdXL31CiCU4C8hSGtk2sG0CoN0RP8w6QY xeJUWZ+p9QV6L1mNAznUGdfQBHDjExcTfV3dhUox1tBWrWAaE+HECBjcMdQ44+n+nF8y 40QUEsAm5oHmNqSGvLLn/6MygRLAWW343GAn1iwobCjV3toljEJGKAGXSB/dGWeg4i4Z x1OChUM1eAStpdBG1qbwERUoksHOpvOt02GNEnpzrkvKPcxbTaLrwTQ1SKWBZsL/N1QF 2CSw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:references:in-reply-to:subject:date :message-id:mime-version:thread-index:content-language; bh=XdVVjlQaDzXcvkg3eAjgyCIk0ErHgTJplyH6MlxEyE0=; b=iP7ccj1p37Gwj8yjAgl3rXh0e3X7frJKecZRnk8uncaOLsKfxVXm5kaQpJZbC0zWQS 7u2mwnvEodbKTW9lUKXIRg0ae8n9Ll8e3UwsTdln8msmottXuX+4ZkHXYzsChBSGH1un Sp01B4UczQ9hvSGrGF0US8wApDPd4SzU1jWVXrJAoFcnnkFkpgWIapgryQg0o0CHe/W4 5atYwwT2YU4Ix/lfVfaMrHtnnMoXTrMNdhqmtTHqIarYRWfuSd0vHmyvXYpQAR+3Hhnd Llo+6FjRMgGQcvBCnVv8gHF1Q8vOVl8vce1ts1lj1vFDUHeaXWczV6ZSaDjiwylc4g+n oECw== X-Gm-Message-State: AOAM533OKeTRYLCEeeX5NB+Ly5cVBTAsUprfIsdDTbIrgNNkUqdHNMrE FgYddZBNT7ZLRcbfFZY7KPdXqEMyACo= X-Google-Smtp-Source: ABdhPJyvFfexhlNhR/NeNmMycsEgDk0TIQalYj34qqaB/C9XFNKLwLocAtMLmk4ZR9sHx1FsSgugCg== X-Received: by 2002:a17:902:e5ce:b029:12b:45c1:2244 with SMTP id u14-20020a170902e5ceb029012b45c12244mr25603286plf.4.1626818494929; Tue, 20 Jul 2021 15:01:34 -0700 (PDT) Return-Path: <12348ung@gmail.com> Received: from UserPC ([103.198.24.78]) by smtp.gmail.com with ESMTPSA id v23sm3779800pje.33.2021.07.20.15.01.33 for (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Tue, 20 Jul 2021 15:01:34 -0700 (PDT) To: "'Rotary motors in aircraft'" References: In-Reply-To: Subject: RE: [FlyRotary] Re: Fwd: Inlet cooling article Date: Wed, 21 Jul 2021 08:01:31 +1000 Message-ID: <007501d77db2$cdbb16c0$69314440$@gmail.com> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0076_01D77E06.9F6970B0" X-Mailer: Microsoft Outlook 16.0 Thread-Index: AQHaIgQt4nVxuKrZCLKOmZkZDk5g1atHIBmw Content-Language: en-us This is a multipart message in MIME format. ------=_NextPart_000_0076_01D77E06.9F6970B0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Charlie, Much wisdom out there, you just have to find the = truth! Max cooling is apparently 30 MPH, so Any faster and it does not = pick up heat before going past. Look at big trucks, that grill is not = only for looks, they slow the air to get max cooling. If too slow they = have a quite large fan that kicks in to drag air through at 30 MPH not = 100! As you say, what do I know =E2=80=93 I have seen too = many that do not work =E2=80=93 without any degree. Neil. =20 From: Rotary motors in aircraft =20 Sent: Wednesday, July 21, 2021 7:07 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Fwd: Inlet cooling article =20 On 7/20/2021 3:26 PM, Marc Wiese cardmarc@charter.net = wrote: Comments? =20 Subject: Inlet cooling article =EF=BB=BF https://www.kitplanes.com/down-to-earth-40/ Sent from my iPhone I remember the Laboda article about enlarging their cooling inlets, but = not many of the details. This: The plenum receives air through two circular air intake ducts behind the = propeller and squeezes it, Bernoulli-style, so that the air accelerates = across the cylinders and between their fins, carrying the heat back, = down and out an outflow "gate" at the back and bottom of the engine = area, forward of the firewall. Is contrary to everything I've ever read about cooling efficiently. = Faster relative flow will always have higher drag, all else being equal. = Accelerating the air even faster than freestream just sounds crazy. My = understanding is that there's a balancing act between having the room in = an a/c to 'recover' (increase) differential pressure across the heat = exchanger (engine fins, in this case), and causing too much drag from = the air going through the fins too fast (there's aerodynamic drag in the = heat exchanger, just like over the a/c itself). It's surprising to me = that James made the plenum the way he did. The rest sounds like putting = bandaids on stuff. The next-to-last image, of the final inlet, shows = what appears to be a *much* smaller plenum inlet than the cowl ring in = front of it, and a rather sharp edged lip where the plenum starts. It = looks like the air would accelerate until it hits that sharp lip, and = immediately go turbulent, which will kill any pressure recovery and = actually slow flow into the cylinder fins.=20 Most Lyc plenums I've seen (even the ones James made for the 4 cyl = engines) have significant volume above the cylinders with smoothly = expanding ducts feeding the plenum. That allows the air to slow in an = organized fashion, which increases *pressure*, which is what actually = makes the air move through the fins. But what do I know; I have an Economics degree.... Charlie =20 = =20 Virus-free. = = www.avast.com=20 =20 ------=_NextPart_000_0076_01D77E06.9F6970B0 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable

Charlie,

=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 Much wisdom out there, = you just have to find the truth!=C2=A0=C2=A0 Max cooling is apparently = 30 MPH, so Any faster and it does not pick up heat before going = past.=C2=A0 Look at big trucks, that grill is not only for looks, they = slow the air to get max cooling.=C2=A0 If too slow they have a quite = large fan that kicks in to drag air through =C2=A0at 30 MPH not = 100!

=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 As you say, what do I know =E2=80=93 I = have seen too many that do not work =E2=80=93 without any = degree.

Neil.

 

From: Rotary motors in aircraft = <flyrotary@lancaironline.net>
Sent: Wednesday, July 21, = 2021 7:07 AM
To: Rotary motors in aircraft = <flyrotary@lancaironline.net>
Subject: [FlyRotary] Re: = Fwd: Inlet cooling article

 

On = 7/20/2021 3:26 PM, Marc Wiese cardmarc@charter.net = wrote:

Comments?

 

Subject: Inlet cooling = article

=EF=BB=BF https://www.kitplane= s.com/down-to-earth-40/

Sent = from my iPhone

I remember the Laboda article about enlarging their = cooling inlets, but not many of the details.
This:
The plenum receives air through two circular air intake ducts behind = the propeller and squeezes it, Bernoulli-style, so that the air = accelerates across the cylinders and between their fins, carrying the = heat back, down and out an outflow "gate" at the back and = bottom of the engine area, forward of the firewall.

Is = contrary to everything I've ever read about cooling efficiently. Faster = relative flow will always have higher drag, all else being equal. = Accelerating the air even faster than freestream just sounds crazy. My = understanding is that there's a balancing act between having the room in = an a/c to 'recover' (increase) differential pressure across the heat = exchanger (engine fins, in this case), and causing too much drag from = the air going through the fins too fast (there's aerodynamic drag in the = heat exchanger, just like over the a/c itself). It's surprising to me = that James made the plenum the way he did. The rest sounds like putting = bandaids on stuff. The next-to-last image, of the final inlet, shows = what appears to be a *much* smaller plenum inlet than the cowl ring in = front of it, and a rather sharp edged lip where the plenum starts. It = looks like the air would accelerate until it hits that sharp lip, and = immediately go turbulent, which will kill any pressure recovery and = actually slow flow into the cylinder fins.

Most Lyc plenums I've = seen (even the ones James made for the 4 cyl engines) have significant = volume above the cylinders with smoothly expanding ducts feeding the = plenum. That allows the air to slow in an organized fashion, which = increases *pressure*, which is what actually makes the air move through = the fins.

But what do I know; I have an Economics = degree....

Charlie

 

V= irus-free. www.avast.com =

 

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