X-Junk-Score: 0 [] X-Cloudmark-Score: 0 [] X-Cloudmark-Analysis: v=2.3 cv=G+5i7Os5 c=1 sm=1 tr=0 a=BMg5uwImetesxz4vmnqzIg==:117 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=J70Eh1EUuV4A:10 a=-ZWx6XDNE4MA:10 a=r77TgQKjGQsHNAKrUKIA:9 a=pGLkceISAAAA:8 a=Ia-xEzejAAAA:8 a=3oc9M9_CAAAA:8 a=hOpmn2quAAAA:8 a=7g1VtSJxAAAA:8 a=46_EVFGh8FaAQfvPe2oA:9 a=yKW9opgGIe7cjRnz:21 a=1SX_rgCHA5oGxvlS:21 a=QEXdDO2ut3YA:10 a=Qa1je4BO31QA:10 a=gvSQh4r-fQ0A:10 a=4PR2P7QzAAAA:8 a=wSq0R_NjQbCdBtSMuAIA:9 a=vwKcZmRuZdeq093W:21 a=7hy6Cj2ciYyX3c1N:21 a=BIf_RO449E4rEKJv:21 a=_W_S_7VecoQA:10 a=Urk15JJjZg1Xo0ryW_k8:22 a=GyA-uvUxXSCciAkwuKQO:22 a=grOzbf7U_OpcSX4AJOnl:22 a=4dqwQCo7Po2mVW515mGf:22 From: "Finn Lassen finn.lassen@verizon.net" Received: from sonic302-3.consmr.mail.bf2.yahoo.com ([74.6.135.42] verified) by logan.com (CommuniGate Pro SMTP 6.2.14) with ESMTPS id 12931765 for flyrotary@lancaironline.net; Fri, 06 Sep 2019 16:27:18 -0400 Received-SPF: pass receiver=logan.com; client-ip=74.6.135.42; envelope-from=finn.lassen@verizon.net DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=verizon.net; s=a2048; t=1567801622; bh=MNFBh9GbhvnSGnjzTvKrlFZYP/nf83kjlG3ocbn1x3k=; h=Subject:To:References:From:Date:In-Reply-To:From:Subject; b=cj+UJBzWHO3prU7s0IqUpwBzIOYl0oFxERy7m8hYw1rcd31Yv38CDyloWme3z2KCect95sN0zqA4iKreA54UQOc0FH/DENGONRWKouxZ9wxghSE3uPlo9jzGP4eNivdux1wHUxc+gxms4NlK0O+LMF/fL1YxbaLouVEERRKgoud7aHsk6HvgBGDGPsJ95wzm5wpgEKYUEJYXYR3cxRNGURSOkc5j0RK4SS+hRrmEBxwk2QW7z4OgyDukC7GOVAY4xa9Z1aIyU8k90U0SB2hyYgB1xX7aOkSasXZu1prz5tKYpBxfrmY0HKM6x0Kc0vUybZaz+p+kxeUEnnfXhrruwA== X-YMail-OSG: uK2njUcVM1l.Rl8Kw3xOcrC1qrUnnL3hBni.jluI239v3cZ9Y3iUVKHive_mVf5 AVb_FVJY9qSE2tmvWrf3LJV_53MaGo2AvmjzkjN_IPYhbnuzSyx9k5R_a9AdLgmIsvgdlnTk6LY3 hdeuRu8u89iGVhOs3s9mQLp4WIwngApB80kDD6oPKdINGOMnkRUrD2Ly3Mk3MiAAC_2lcf3eQWun 4HnbVudyQZazxVzZaylirsRogdAc8HwyzLCWg.FJ6Jzc7ZDc17Kbheh0md1bUTVBXTrGJYRZ98fk 1NWlpRjAukEuPwVbxixovcVZkPqxjF_eY9zVC0sHoggWKDeMQ9Z9ZYh3Apq_79_doPBR1sUGw1v7 lcpcjMS2DImU1OKOw.YGEAw9A1OPJHJJ7e6ai0vj8x47h.IVsEaAP4zjRJOvade7Wx6r7qUH5gjb x4E4CTnaB9ML528vqfHSLHLuM2P5Zocsat3gIvJ0KZhzKNyvBxrZ2OXBYCY0dxazVNx6.9OuxsKq uPVguF9jaAAVW155zZGvTxzK1s5p567ZnSAaEJLIeOMsQQo0rx8tpsMnDQe6uSVLh5QwyyaEP8KR 7aQMH_aRmodDRH3HOAjFYz3DShBms6Ddzy3JFoIiMQgPGsrxr.Hkw5gU2VV4sjLBS2QGi0lf1Q1T W1vfFN4Y0IfZlwRryWgB_oUSq5Y58F0HYlcwwdY_BQ0HQptY5YLudenENESxaYXJRPczBcxqOxgT uusrPmyfj0udQ5mijPSbNABhMXeEwYNLwnXNsGx4xjYtmaCcdgmYY93LFMdHIp7vJfeGuXhOqyj7 nJDtmTv003fPr3xIe9K.scIWZh9LutpOIHwLXeNDoL5PwVc0NBArDO7REEEKNmkWpBroUvtXskZh DXDjfzmvLrfFHpbx5oogIq_QrQ_FU9oU0wUgoJ_rA6qy5pPYzdKcuP4VnqNiUGyuet8B5jejXIE9 96I7HCOvNa2NP4H.noqz43CTKWZ0l8A2wxqWVlrTyMnJUvD1dRY0zb9.VNIEgAkZPHhIOvBZGdpy eF5ST02vYqChuyzkqcht5KixLUvThsqSr2L8UB4T4Yn9w1Rljglzh8XRVpTBAYFgTBmj4sJNCaLF jFgW_3PufcaVeAxL6iNCOWQTdf8P8ZXzGrzYMyJnNoXfdLawrV6C0ME6JT4HM8ZlaVcwedcK.e9n VZb9gAwmQxt4aOiN96h.q5W3mHyRtuzJd9lozF5.UMPrtGytc1NV.p4aYzDs8jFexMYcyOGQBxF0 WmT.O0jxuZI2OglQrEndD3KEu_33gtZQ9pjDwDKiV0Ff2rw3NrewhQc9nrwkqli3blOy0gNrly3e ajg-- Received: from sonic.gate.mail.ne1.yahoo.com by sonic302.consmr.mail.bf2.yahoo.com with HTTP; Fri, 6 Sep 2019 20:27:02 +0000 Received: by smtp419.mail.bf1.yahoo.com (Oath Hermes SMTP Server) with ESMTPA ID e3e358299ae6d08b841de4a59a9aeb48; Fri, 06 Sep 2019 20:27:00 +0000 (UTC) Subject: Re: [FlyRotary] Re: Part specs-radiator design To: Rotary motors in aircraft References: Message-ID: Date: Fri, 6 Sep 2019 16:26:56 -0400 User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/alternative; boundary="------------150FB19B79171641B38206DD" Content-Language: en-US This is a multi-part message in MIME format. --------------150FB19B79171641B38206DD Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Thanks Charlie, I'll definitely use your leaf blower test. Looks like I hate the idea of making ducts. I'd really like to use as much as the existing cowling as possible. The thing that makes the most sense (at the moment) is a 12" wide x 17" (plus tanks) long, 2.5" thick radiator slanted with bottom at front and top at rear (cleanest exit air flow down and out). The easiest to duct for the incoming air is probably top at front and bottom at rear. With a 12" or wider radiator I might be able to use existing cowl bottom as bottom of the duct, use straight sides and just have to shape the top of the duct to proper wedge. Extending the scoop (maybe 10"W x 3"H) almost out to the prop (27" to rear) may allow for almost straight sides? Someone who loathes fiberglass less would probably chop off the entire O-360 air/filter inlet from the bottom of the cowling and make something more well designed. Finn On 9/6/2019 2:19 PM, Charlie England ceengland7@gmail.com wrote: > I've never experimented with minimal angles off perpendicular; those > may not matter much. But at some point, you end up with a 'wedge' > diffuser, and then the shape of the wedge becomes important. Finn, > look at K&W chapter 12; section 12-2 deals with 'oblique flow'. BTW, > figure 12-12 in that chapter doesn't seem to jive with real world > experiments. Tracy found, and warned me about, the need to pinch the > aft end of a wedge significantly to avoid the vast majority of the > flow happening in the aft third of the core. It's impressive how much > pinch is needed to keep flow even across the core. > > Charlie > > On Fri, Sep 6, 2019 at 1:05 PM William Jepson wrjjrs@gmail.com > > wrote: > > Rich. I said ???if the airflow is there???. The question I was > answering was about the angle of the heat exchanger. We do need to > be sure we don???t trap air inside, and of course that there is > actual airflow through. Many of our rotary installs would be > helped by using manometers to check if the area behind the > radiators are lower pressure. Motorcycles are another ???special > case??? since most require the air to turn 90 degrees to exit the > fairing. The only really excellent design on bikes was the > Britten. I raced motorcycles in the past and the only different > configuration I saw was the Honda RC 51. ( if I have the right > number) with both radiators in the cheek position in the fairing. > Bill Jepson > > On Fri, Sep 6, 2019 at 10:44 AM A R Goldman argoldman@aol.com > > wrote: > > Not totally true as I learned from overheating my norton > rotary dragonfly. It makes sense that air flows from high > pressure to low. But. Many times oh has a mind of its own > counterintuitively. For example as the air exit the exchanger > if it is not allowed to exit straight or gently deflected, > independent of the delta the air will stagnate and not go > where you expect. Pay as much attention to the exit as you do > with the entry > > Yrmv > > Rich > > Sent from my iPhone > > On Sep 6, 2019, at 11:52 AM, William Jepson wrjjrs@gmail.com > > wrote: > >> Answer is nothing; provided the airflow is there. Also there >> needs to be a vent or tap to get all the air out of the inside. >> Bill Jepson >> >> On Fri, Sep 6, 2019 at 8:38 AM Marc Wiese >> cardmarc@charter.net >> > > wrote: >> >> Finn asks- >> "BTW, what happens when you lay down (at a 20 degree) >> angle a radiator that is designed to be upright?" >> >> I always wondered about that myself. The stock FD (3rd >> gen) radiator has to be at about a 45 degree angle (?) to >> the incoming airstream. And it has 2 "supplemental" >> staged electric fans (no pump fan), one is always on if >> the AC is on, the fans have different blades and >> different speeds controlled by ECU and temp sensor. I >> suppose the fins are canted or perhaps they are best >> tilted to airflow to create turbulence and help remove >> some heat..........don't know much about radiator >> design............ >> MW >> >> -- >> Homepage: http://www.flyrotary.com/ >> Archive and UnSub: >> http://mail.lancaironline.net:81/lists/flyrotary/List.html >> >> >> -- >> Homepage: http://www.flyrotary.com/ >> Archive and UnSub: >> http://mail.lancaironline.net:81/lists/flyrotary/List.html >> --------------150FB19B79171641B38206DD Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 8bit
Thanks Charlie,

I'll definitely use your leaf blower test.

Looks like I hate the idea of making ducts. I'd really like to use as much as the existing cowling as possible.

The thing that makes the most sense (at the moment) is a 12" wide x 17" (plus tanks) long, 2.5" thick radiator slanted with bottom at front and top at rear (cleanest exit air flow down and out). The easiest to duct for the incoming air is probably top at front and bottom at rear. With a 12" or wider radiator I might be able to use existing cowl bottom as bottom of the duct, use straight sides and just have to shape the top of the duct to proper wedge. Extending the scoop (maybe 10"W x 3"H) almost out to the prop (27" to rear) may allow for almost straight sides?

Someone who loathes fiberglass less would probably chop off the entire O-360 air/filter inlet from the bottom of the cowling and make something more well designed.

Finn

On 9/6/2019 2:19 PM, Charlie England ceengland7@gmail.com wrote:
I've never experimented with minimal angles off perpendicular; those may not matter much. But at some point, you end up with a 'wedge' diffuser, and then the shape of the wedge becomes important. Finn, look at K&W chapter 12; section 12-2 deals with 'oblique flow'. BTW, figure 12-12 in that chapter doesn't seem to jive with real world experiments. Tracy found, and warned me about, the need to pinch the aft end of a wedge significantly to avoid the vast majority of the flow happening in the aft third of the core. It's impressive how much pinch is needed to keep flow even across the core.

Charlie

On Fri, Sep 6, 2019 at 1:05 PM William Jepson wrjjrs@gmail.com <flyrotary@lancaironline.net> wrote:
Rich. I said ???if the airflow is there???. The question I was answering was about the angle of the heat exchanger. We do need to be sure we don???t trap air inside, and of course that there is actual airflow through. Many of our rotary installs would be helped by using manometers to check if the area behind the radiators are lower pressure. Motorcycles are another ???special case??? since most require the air to turn 90 degrees to exit the fairing. The only really excellent design on bikes was the Britten. I raced motorcycles in the past and the only different configuration I saw was the Honda RC 51. ( if I have the right number) with both radiators in the cheek position in the fairing.
Bill Jepson

On Fri, Sep 6, 2019 at 10:44 AM A R Goldman argoldman@aol.com <flyrotary@lancaironline.net> wrote:
Not totally true as I learned from overheating my norton rotary dragonfly. It makes sense that air flows from high pressure to low. But. Many times oh has a mind of its own counterintuitively. For example as the air exit the exchanger if it is not allowed to exit straight or gently deflected, independent of the delta the air will stagnate and not go where you expect. Pay as much attention to the exit as you do with the entry

Yrmv

Rich

Sent from my iPhone

On Sep 6, 2019, at 11:52 AM, William Jepson wrjjrs@gmail.com <flyrotary@lancaironline.net> wrote:

Answer is nothing; provided the airflow is there. Also there needs to be a vent or tap to get all the air out of the inside.
Bill Jepson??

On Fri, Sep 6, 2019 at 8:38 AM Marc Wiese cardmarc@charter.net <flyrotary@lancaironline.net> wrote:
Finn asks-
"BTW, what happens when you lay down (at a 20 degree) angle a radiator that is designed to be upright?"

I always wondered about that myself. The stock FD (3rd gen) radiator has to be at about a 45 degree angle (?) to the incoming airstream. And it has 2 "supplemental" staged electric fans (no pump fan), one is always on if the AC is on, the fans have different blades and different speeds controlled by ECU and temp sensor. I suppose the fins are canted or perhaps they are best tilted to airflow to create turbulence and help remove some heat..........don't know much about radiator design............
MW

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