X-Junk-Score: 0 [] X-Cloudmark-Score: 0 [] X-Cloudmark-Analysis: v=2.2 cv=aM2ykv1m c=1 sm=1 tr=0 a=RPZgViSN43jj7cy/UnIhow==:117 a=Gcxronpr07aM3adkepbldQ==:17 a=x7bEGLp0ZPQA:10 a=VqmtQeTB-p0A:10 a=KeKAF7QvOSUA:10 a=Ia-xEzejAAAA:8 a=_6GpL_ENAAAA:8 a=Wma5eQDI0Qxv1pJgxLQA:9 a=-EU-WeEGcj-KgZaI:21 a=9K1SRzpDJlR5GrjI:21 a=QEXdDO2ut3YA:10 a=yMhMjlubAAAA:8 a=Xb3CnXNdLQRa2zZKGW8A:9 a=C9JnuQ-87zn3i2ux:21 a=yOqVJOE56nwKA6DL:21 a=rmyseTWwyqobgZNJ:21 a=UiCQ7L4-1S4A:10 a=hTZeC7Yk6K0A:10 a=_W_S_7VecoQA:10 a=frz4AuCg-hUA:10 a=Urk15JJjZg1Xo0ryW_k8:22 From: "Tracy" Received: from mail-io0-f172.google.com ([209.85.223.172] verified) by logan.com (CommuniGate Pro SMTP 6.2c3) with ESMTPS id 10032017 for flyrotary@lancaironline.net; Mon, 21 Aug 2017 08:46:48 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.223.172; envelope-from=rwstracy@gmail.com Received: by mail-io0-f172.google.com with SMTP id g71so51616973ioe.5 for ; Mon, 21 Aug 2017 05:46:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:references:from:in-reply-to:message-id:date:to :content-transfer-encoding:mime-version; bh=b5uZGagO+mbNUQCn16Bs46LurX9pKVQRsOJ8YGcA7ck=; b=uG3mMq4tarp2bqOezQ4kwF7jYtLMN503OXum9zlvza5tpgJejqwssCwf7yl7wV7Z3Q JVsoUmeIgjA+HLnQNUGj6FEFy1ggkNIIqKSHeGhS1w5rtKXpieqn1iI99xniCjD6tznC C4iVpWXwH4jLXLrH8RyJAnUvXk84o7gAlkxBDWaKOpGHU0J6Z1nmxlszw8sp3VOQI71x ur4MyYYEWxAH1q6Z8Fq6ddIwwyMDSM8zTaL8sgdu654f9DlwtR3uJ7l4sUy5gO0R5qTu gEA2+qmYFWXoQt2mTkmi7XFBONjskQ7vzAZu/TsMIaOVgeZa1h7FlzioXzJm0D8sleuK zNkg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:references:from:in-reply-to:message-id :date:to:content-transfer-encoding:mime-version; bh=b5uZGagO+mbNUQCn16Bs46LurX9pKVQRsOJ8YGcA7ck=; b=kxiV6CIFHnfzOZeLNYanZ6VIro42nIsGsKzbNiCS+0J7seueThtugM2uMKpjbBkqAS 8plek2JYTVs75Ql/tNw7r39hgbLNNurf9K23qd0EP8yRU/3SD+94LJNKRKN14CDTJvVk xyirApjymE9Rz75afVvVxrWIYiHBpcN1Yqq6cV32YErzR6PC7vz7sTYDRZU8W1bD+ImF +JW5xYARg+Jh5EReBuMJZXWbkvk5AR1drtpD2YzZvRjEudd2B20H6OqjFR1LHdUfPi0p 1kVlsk5PvKo5pPh3x/Q+2dN6VSyEuFCsxblBFcVGuAHrA5TJHmGhh1ZHiIfOK8DB7L+M 8uoQ== X-Gm-Message-State: AHYfb5gEdafAx/sNCOIrdp6tRDcMjwul0xJHYuUhU66j2JEmD7sZHnlF j3sHcQIs+2+y2GexZzE= X-Received: by 10.107.137.86 with SMTP id l83mr1311351iod.305.1503319591305; Mon, 21 Aug 2017 05:46:31 -0700 (PDT) Return-Path: Received: from [10.240.219.80] (195.sub-97-44-3.myvzw.com. [97.44.3.195]) by smtp.gmail.com with ESMTPSA id j82sm5766055ioo.44.2017.08.21.05.46.28 for (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 21 Aug 2017 05:46:29 -0700 (PDT) Subject: Re: [FlyRotary] Re: Coolers References: Content-Type: multipart/alternative; boundary=Apple-Mail-4EB5C648-0159-4CA7-AB62-73E1EE90FE61 X-Mailer: iPad Mail (13G36) In-Reply-To: Message-Id: Date: Mon, 21 Aug 2017 06:46:25 -0600 To: Rotary motors in aircraft Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (1.0) --Apple-Mail-4EB5C648-0159-4CA7-AB62-73E1EE90FE61 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Hi Will, =20 My rule of thumb for rad core volume is between 2 and 3 CI per HP. At 375 C= I you would be on the small side but I think your calculation of CI is off. = Thick rads can be efficient but will need more CI.=20 The needed CI is of course affected by core design, duct efficiency, aircra= ft speed, etc. At 4.5" thick you should be in at least a 200 mph top speed d= esign, otherwise you might not have enough diffuser pressure to force the ai= r through. Other thoughts: Airflow around the engine is a waste. Very little cooling f= or a lot of drag. There is no such thing as drag being a good idea unless y= ou are landing (flaps) or flying a Stuka dive bomber. A little Cooling Airf= low around coils, alternators, electronics, etc. is a good idea. =20 Personally I've had good luck with the RX-7 oil cooler. There is a big mi= smatch between the delta P air pressure required between that cooler and you= r rad though. Separate ducts would be a good idea otherwise the oil cooler m= ight hog most of the airflow. Even the pressure on the back side of the he= at exchangers can affect the balance but it sounds like you are going for se= parate outlets so may not be a factor here. Let us know how the project goes! Tracy Crook =20 Sent from my iPad > On Aug 20, 2017, at 19:42, william Aldridge w= rote: >=20 > Ok I've spent the last few years on Paul Lamars list and got tired of it. I= 'm designing and building my own design and was wondering what you guys say i= s the right size for the water and oil coolers? I plan on p-porting the eng= ine so am expecting 200+ hp. I know there's a lot of factors that go into ra= d sizing but let's just say i get a moderately efficient cooling system, how= much volume do i need? I've got a cross counter flow setup drawn in now t= hat is about 375 cu inches and 10.5 x 17.75 on the face and about 4.5 inches= deep. The water cooler will be mounted perpendicular to the airstream wit= h an adjustable exit ramp. For the oil cooler I=E2=80=99m planning on using= a standard rx 7 oil cooler that will use a wedge diffuser on the intake and= exhaust out shark gills on the side of the cowling. I will also have quite a= bit of airflow around the engine itself. That will probably take the airsp= eed down somewhat but it=E2=80=99s such a slick small airframe that I think i= t could get uncomfortably close to Vne in level flight, so a little unnecess= ary drag might be a good thing. > =20 > Thanks,=20 > =20 > Will Aldridge=20 > =20 > =20 > Sent from Mail for Windows 10 > =20 > From: Todd Bartrim > Sent: Sunday, August 20, 2017 4:56 PM > To: Rotary motors in aircraft > Subject: [FlyRotary] Re: Coolers > =20 > Another great example of how tech changes our lives. Back when, we had to g= uess at what was happening under the cowl. Now a few clicks on Amazon and 2 d= ays later we can have all the investigative tools we need to know instead of= guessing. > =20 >=20 > Virus-free. www.avast.com >=20 > Todd Bartrim > =20 > On Sun, Aug 20, 2017 at 2:45 PM, Ernest Christley wrote: > Just a point to highlight what Todd was saying about exit ducting. > =20 > On the Dyke Delta I built, I had a water cooler under the cowl. The other= water cooler and oil cooler were buried in the strakes. The air exited the= cooler under the cowl close to the firewall, and was supposed to go down an= d out the bottom. It didn't do that. > =20 > What it did was set up a horizontal whirlwind inside the cowl. The air hi= t the firewall and then spun around clockwise. I discovered what was happen= ing during the investigation of why some hoses were melting. I constructed a= crude dam to force the air out the cowl exit, and saw a significant drop in= temps. > =20 > All that is to say that the airflow INSIDE the cowl is as important as the= flow outside. Today, I would tuft the engine with pieces of yarn on hoses, w= ires, and engine mount tubes. I have a tiny camera with a 15ft cord that tu= rns my phone into a video surveillance monitor. I'd stick it in various pla= ces under the cowl and see how the air flows with the engine running. > =20 > =20 >=20 > On Sunday, August 20, 2017 4:22 PM, Todd Bartrim wrote: > =20 >=20 > I didn't crunch any numbers in my decision to use this Laminova heat excha= nger, I only knew that in climb and level flight I had different cooling bet= ween oil & water and figured I could balance it out with this heat exchanger= at a small price in weight. It certainly doesn't increase the cooling of th= e system as a whole. > It should be pointed out that these are not coolers, only heat exchangers= . So if a oil/water cooling system doesn't have adequate cooling to begin wi= th, then this will do nothing to address that. > In my case I found that I could climb from 2000' ASL (field) to 10000' ASL= in 3 minutes before my coolant temps hit redline, but I still had plenty of= room on my oil temps. In level flight my coolant temps would drop but my oi= l temps would slowly increase to redline. So I figured this would help me bo= rrow from Peter to pay Paul. It still didn't address cooling shortfalls prop= erly. > I believe the biggest culprit in this was the shape and position of my o= il cooler inlet which was form over function (hey, it looked good). > Now I have made a lot of other changes which hopefully should address i= mproper cooling airflow. As well as reshaping the oil cooler inlet duct I al= so did outlet ducting for the oil cooler, intercooler and right coolant radi= ator. I did not build a outlet duct from the left radiator due to it's close= proximity to the turbo exhaust pipe. This interfered with the space require= d for a proper exit duct and I figured it probably would be a good idea to h= ave some airflow over the turbo. Previously I had only ducted my inlets and l= eft the air to find it's own way out of the cowl through what I believed wer= e adequate sized exits. Ed Anderson spent a lot of time researching cooling a= ir flows and finally was able to beat it into me that exit ducting is every b= it as important as inlet ducting. > The other change I made which I hope will have a significant effect is I= bought a new set of deep pitch blades for my IVO prop. I also cut it down f= rom 76" to 70". This should give me a higher cruise speed with the accompany= ing increase in cooling airflow with the same RPM. > So with all these changes it's unknown if this Laminova cooler will have a= ny benefit but I'm certainly not going to remove it as it it's only cost at t= his point is a few pounds which if I need to get rid of that I'll just start= jogging again... not a bad idea anyways :-) > =20 > On Sun, Aug 20, 2017, 09:46 Thomas Mann, wro= te: > As a side note to these observations there is something to be said about o= vercooling the engine oil. (i.e. cooling the oil too much at higher altitude= s or in cold conditions.) > An oil-to-coolant system help to moderate that scenario. > =20 > T Mann > =20 > Sent from Windows Mail > =20 > =20 > =20 >=20 > Virus-free. www.avast.com > =20 >=20 > =20 > =20 --Apple-Mail-4EB5C648-0159-4CA7-AB62-73E1EE90FE61 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
Hi Will,   
My rul= e of thumb for rad core volume is between 2 and 3 CI per HP.  At 375 CI= you would be on the small side but I think your calculation of CI is off. &= nbsp;Thick rads can be efficient but will need more CI. 

=
The needed CI  is of course affected by core design, duct ef= ficiency, aircraft speed, etc.  At 4.5" thick you should be in at least= a 200 mph top speed design, otherwise you might not have enough diffuser pr= essure to force the air through.

Other thoughts: &n= bsp;Airflow around the engine is a waste.  Very little cooling for a lo= t of drag.  There is no such thing as drag being a good idea unless you= are landing (flaps) or flying a Stuka dive bomber.  A little Cooling A= irflow around coils, alternators, electronics, etc. is a good idea.  

Personally I've had good luck with the RX-7 oil cool= er.    There is a big mismatch between the delta P air pressure re= quired between that cooler and your rad though.  Separate ducts would b= e a good idea otherwise the oil cooler might hog most of the airflow.  = Even the pressure on the back side of the heat exchangers can affect the ba= lance but it sounds like you are going for separate outlets so may not be a f= actor here.

Let us know how the project goes!
=

Tracy Crook
   

Sent fro= m my iPad

On Aug 20, 2017, at 19:42, william Aldridge &l= t;flyrotary@lancaironline.net= > wrote:

Ok I've spent the last few years on Paul Lamars list a= nd got tired of it. I'm designing and building my own design and was wonderi= ng what you guys say is the right size for the water and oil coolers?  = I plan on p-porting the engine so am expecting 200+ hp. I know there's a lot of factors that go into rad sizing b= ut let's just say i get a moderately efficient cooling system, how much volu= me do i need?   I've got a cross counter flow setup drawn in now that i= s about 375 cu inches and 10.5 x 17.75 on the face and about 4.5 inches deep.   The water cooler will b= e mounted perpendicular to the airstream with an adjustable exit ramp. = For the oil cooler I=E2=80=99m planning on using a standard rx 7 oil cooler= that will use a wedge diffuser on the intake and exhaust out shark gills on the side of the cowling. I will also have q= uite a bit of airflow around the engine itself.  That will probably tak= e the airspeed down somewhat but it=E2=80=99s such a slick small airframe th= at I think it could get uncomfortably close to Vne in level flight, so a little unnecessary drag might be a good thing.

 

Thanks, 

 

Will Aldridge 

 

 

Sent from Mail for Windows 10

 

From: Todd Bartrim
Sent: Sunday, August 20, 2017 4:56 PM
To: Rotary motors in a= ircraft
Subject: [FlyRotary] Re: Coolers

 

Another great example of how tech changes our lives. B= ack when, we had to guess at what was happening under the cowl. Now a few cl= icks on Amazon and 2 days later we can have all the investigative tools we n= eed to know instead of guessing.

 

3D"https://ipmcdn.avast.com/ima==

Virus-free. www.avast.com


Todd Bartrim

 

On Sun, Aug 20, 2017 at 2:45 PM, Ernest Christley <= ;flyrotary@= lancaironline.net> wrote:

Just a point= to highlight what Todd was saying about exit ducting.

=

 <= /o:p>

On the Dyke D= elta I built, I had a water cooler under the cowl.  The other water coo= ler and oil cooler were buried in the strakes.  The air exited the cooler under the cowl close to the firewall, and was suppose= d to go down and out the bottom.  It didn't do that.<= /p>

 <= /o:p>

What it did w= as set up a horizontal whirlwind inside the cowl.  The air hit the fire= wall and then spun around clockwise.  I discovered what was happening during the investigation of why some hoses were melting.=   I constructed a crude dam to force the air out the cowl exit, and saw= a significant drop in temps.

 <= /o:p>

All that is t= o say that the airflow INSIDE the cowl is as important as the flow outside. T= oday, I would tuft the engine with pieces of yarn on hoses, wires, and engine mount tubes.  I have a tiny camera wi= th a 15ft cord that turns my phone into a video surveillance monitor.  I= 'd stick it in various places under the cowl and see how the air flows with t= he engine running.

 <= /o:p>

 

On Sunday, Augus= t 20, 2017 4:22 PM, Todd Bartrim <flyrotary@lancaironline.net> wrote:

 

I didn't cru= nch any numbers in my decision to use this Laminova heat exchanger, I only k= new that in climb and level flight I had different cooling between oil & water and figured I could balance it out with thi= s heat exchanger at a small price in weight. It certainly doesn't increase t= he cooling of the system as a whole.

 It sho= uld be pointed out that these are not coolers, only heat exchangers. So if a= oil/water cooling system doesn't have adequate cooling to begin with, then this will do nothing to address that.=

In my case I= found that I could climb from 2000' ASL (field) to 10000' ASL in 3 minutes b= efore my coolant temps hit redline, but I still had plenty of room on my oil temps. In level flight my coolant temps would d= rop but my oil temps would slowly increase to redline. So I figured this wou= ld help me borrow from Peter to pay Paul. It still didn't address cooling sh= ortfalls properly.

  I bel= ieve the biggest culprit in this was the shape and position of my oil cooler= inlet which was form over function (hey, it looked good).

   = ;Now I have made a lot of other changes which hopefully should address impro= per cooling airflow. As well as reshaping the oil cooler inlet duct I also did outlet ducting for the oil cooler, intercooler and ri= ght coolant radiator. I did not build a outlet duct from the left radiator d= ue to it's close proximity to the turbo exhaust pipe. This interfered with t= he space required for a proper exit duct and I figured it probably would be a good idea to have some airfl= ow over the turbo. Previously I had only ducted my inlets and left the air t= o find it's own way out of the cowl through what I believed were adequate si= zed exits. Ed Anderson spent a lot of time researching cooling air flows and finally was able to beat it= into me that exit ducting is every bit as important as inlet ducting.<= /o:p>

  The o= ther change I made which I hope will have a significant effect is I bought a= new set of deep pitch blades for my IVO prop. I also cut it down from 76" to 70". This should give me a higher cruise speed with= the accompanying increase in cooling airflow with the same RPM.<= /span>

So with all t= hese changes it's unknown if this Laminova cooler will have any benefit but I= 'm certainly not going to remove it as it it's only cost at this point is a few pounds which if I need to get rid of that I= 'll just start jogging again... not a bad idea anyways :-)=

 <= /o:p>

On Sun, Aug 2= 0, 2017, 09:46 Thomas Mann, <flyrotary@lancaironline.net> wrote:

As a side no= te to these observations there is something to be said about overcooling the= engine oil. (i.e. cooling the oil too much at higher altitudes or in cold conditions.)

An oil-to-co= olant system help to moderate that scenario.

 <= /o:p>

T Mann<= /o:p>

 <= /o:p>

Sent from Wi= ndows Mail

 <= /o:p>

 <= /o:p>

 <= /o:p>

3D"https://ipmcdn.avast.com/ima==

Virus-free. www.avast.com

 

 

 

= --Apple-Mail-4EB5C648-0159-4CA7-AB62-73E1EE90FE61--