<marv>.


"william Aldridge" <flyrotary@lancaironline.net> wrote:

>
> http://www.homebuiltairplanes.com/forums/showthread.php?t=16831
>
> The above link is the build thread for my plane. Not very far along but just
>got a permanent workshop so hopefully it'll pick up the pace.
>
> I tried attaching a few pics but got a message fail for too big a message
>
> Will
>
>
> Sent from my Verizon, Samsung Galaxy smartphone
>
>
> -------- Original message --------
>From: Todd Bartrim <flyrotary@lancaironline.net>
> Date: 8/21/17 12:17 PM (GMT-07:00)
> To: Rotary motors in aircraft <flyrotary@lancaironline.net>
> Subject: [FlyRotary] Re: Coolers
>
> Hi Will;
>   Tracy has given you a good rule of thumb for sizing, so I'll just add a
>few comments.
>First the oil cooler. It seems these days that many consider the stock oil
>cooler to be too restrictive and they may be right so it may be worth
>investigating other options, however as Tracy just mentioned, he has had good
>luck with the stock cooler. Which is what I like to hear as I too am using a
>stock cooler. If I was to change it, the replacement would have to be exactly
>the same size as I'm not in any mood to do more fiberglassing, painting, etc
>on the cowl. I believe the stock cooler did change a fair bit over the years
>and I'm not even sure what year mine was from, but there could be some
>variation in stock coolers that you may have to consider.
>   Rads have also changed in preference over the years I've been on this
>list. Air conditioner evaporator cores seem to have fallen out of favor, but
>at one time they were quite commonly used likely due to the ease of mounting
>them directly behind the air inlets on either side of the ever popular RV
>aircraft and similar airframes. Which is exactly what I have. Tracy, Ed and
>others also successfully used this configuration if I recall. Tracey may add
>more here, but I know his RV4 Otter was cooled this way, but his higher
>powered 20B RV8 likely has more cooling requirements than could be provided
>for with these coolers.
>    Your airframe and it's configuration will have a large effect on your
>choice of cooler(s). What is that you are building? And how far along are
>you? I made the choice to use a rotary back when I was just building the tail
>feathers, so engine considerations were always on my mind throughout the
>building process.
> You'll find on this list that nobody will tell you how you have to build
>your engine install, you left that behind on the other list, however asking
>questions, posting pics, etc will usually earn a few insightful comments. And
>at times when the list is quiet it helps to get us talking again.
> So when you're at a stage where you can take some pics of your current
>install, feel free to share them.
>
> Todd,     feeling eclipse envy :-(
>
> Todd Bartrim
>
> On Sun, Aug 20, 2017 at 6:42 PM, william Aldridge
><flyrotary@lancaironline.net<mailto:flyrotary@lancaironline.net>> wrote:
> 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
>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 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
>that 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 with
>an adjustable exit ramp.  For the oil cooler I’m 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 airspeed down
>somewhat but it’s such a slick small airframe that 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<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows
>10
>
>From: Todd Bartrim<mailto:flyrotary@lancaironline.net>
> Sent: Sunday, August 20, 2017 4:56 PM
> To: Rotary motors in aircraft<mailto:flyrotary@lancaironline.net>
> Subject: [FlyRotary] Re: Coolers
>
> Another great example of how tech changes our lives. Back when, we had to
>guess at what was happening under the cowl. Now a few clicks on Amazon and 2
>days later we can have all the investigative tools we need to know instead of
>guessing.
>
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> Todd Bartrim
>
> On Sun, Aug 20, 2017 at 2:45 PM, Ernest Christley
><flyrotary@lancaironline.net<mailto:flyrotary@lancaironline.net>> wrote:
> Just a point to highlight what Todd was saying about exit ducting.
>
> 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 and
>out the bottom.  It didn't do that.
>
> What it did was set up a horizontal whirlwind inside the cowl.  The air hit
>the firewall 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.
>
> 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,
>wires, and engine mount tubes.  I have a tiny camera with 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 the engine running.
>
>
> On Sunday, August 20, 2017 4:22 PM, Todd Bartrim
><flyrotary@lancaironline.net<mailto:flyrotary@lancaironline.net>> wrote:
>
> I didn't crunch any numbers in my decision to use this Laminova heat
>exchanger, I only knew that in climb and level flight I had different cooling
>between 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 the 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 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 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 oil
>temps would slowly increase to redline. So I figured this would help me
>borrow from Peter to pay Paul. It still didn't address cooling shortfalls
>properly.
>  I believe 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
>improper cooling airflow. As well as reshaping the oil cooler inlet duct I
>also did outlet ducting for the oil cooler, intercooler and right coolant
>radiator. 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
>required for a proper exit duct and I figured it probably would be a good
>idea to have some airflow over the turbo. Previously I had only ducted my
>inlets and left the air to find it's own way out of the cowl through what I
>believed were adequate sized 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.
>  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
>from 76" to 70". This should give me a higher cruise speed with the
>accompanying increase in cooling airflow with the same RPM.
> So with all these 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 :-)
>
> On Sun, Aug 20, 2017, 09:46 Thomas Mann,
><flyrotary@lancaironline.net<mailto:flyrotary@lancaironline.net>> wrote:
> As a side note 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-coolant system help to moderate that scenario.
>
> T Mann
>
> Sent from Windows Mail
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