Mailing List flyrotary@lancaironline.net Message #66583
From: Bruce Cosgrove bcosgrove@mac.com <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Ross Farnham - Cooling video
Date: Tue, 2 Feb 2021 10:58:37 +1100
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Matt,

I still have lots to do  - Am almost ready to commence mounting the engine.  I believe I have the same tango model as you with the extra fuel capacity in the wings, so will try mounting the engine out further forward to get the balance right?  Not sure if there are other options?

Bruce Cosgrove


On 29 January 2021 at 13:11:47, Matt Boiteau mattboiteau@gmail.com (flyrotary@lancaironline.net) wrote:

This summer I will design a wireless circuit board that can do 6 temperature probes and 6 pressure ports running off batteries that will send data to cell phone/laptop for capturing. Give us real data to test out different diffuser designs. 
 
Charlie, any pictures of your turning vanes? I did a trumpet to wedge diffuser and I don't (only guessing here) think the wedge shapes work as well as they do. Will add some turning vanes to shoot more air into the front of the rads. You are right that I am tail heavy and probably can't do a belly mount :( So the best bet is to get a thicker smaller rad.

Le Roux, I have talked with Alex a bunch over exit louvers on the side. We are hoping to tune the exhaust dumping better to help pull air out of the bottom of the cowl. I don't see too many exit louvers though on planes. Any reason for it?

Bobby, how did you measure the good airflow? Magnetometers? Won't your ground cooling be harder with a belly mount, the further away from the prop ?

Bruce, how far along are you? The tango might be tail heavy like mine, have you done a W&B yet? I am skeptical on P-port = 250hp, very skepataple. I am 10kts slower than a standard lycoming engine in the tango 2, even being p-ported.
 
- Matt Boiteau


On Thu, Jan 28, 2021 at 5:13 PM Bruce Cosgrove bcosgrove@mac.com <flyrotary@lancaironline.net> wrote:
Matt

I have decided to use a belly mount radiator on my tango 2.  Have been dithering around for ages without making a decision - Ross's excellent articles have convinced me to go with this setup.  
I have decided on 20” x 7” x either 68 mm 0r 81 mm   The 68 mm (2 3/4” will give approximately 385 cubic”  the 81 mm approx 455 cubic “ which is around Neil’s recommendation.  I have a P Lamar designed radiator which he was confident would cool up to 250 hp (two 1/2 “ wide cores adding up to 330 cubic “ so hopefully the thinner 68mm core should be okay given the lower drag and straight through flow characteristics   I am looking at around 63 “ length for the pod to improve flow characteristics - All constructive input welcome   I am not sure about the best external shape!  a very rough sketch is attached

Bruce


On 28 January 2021 at 12:07:13, Matt Boiteau mattboiteau@gmail.com (flyrotary@lancaironline.net) wrote:

Ross does the SDS EFI system and did 2 videos on cooling his Subaru engine.

https://www.youtube.com/watch?v=GGXXEgqhmmc&ab_channel=rv6ejguy

It seems him and Tracy agree that we need a thicker core, then the 1" Paul L kept on suggesting. My coolant rad is almost as wide as the plane with the 1" truck core.  

I'm definitely not happy with my cooling setup, but needed to get moving and finish the plane. Can sit around all day talking about it, or start with something and get better in time. I'm done the flyoff hours in FL and hoping to bring the plane back to Canada in the spring where I can tinker with it then. 3D draw things out and get suggestions from people then.

What do you guys think of a belly mount coolant rad? How would we plum the exhaust out of the way? Keep oil coolant in the cowl? Or Below the engine?





- Matt Boiteau
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