Mailing List flyrotary@lancaironline.net Message #64563
From: Neil Unger 12348ung@gmail.com <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] 3D printing - Oil inlet
Date: Mon, 7 Jan 2019 07:09:16 +1100
To: Rotary motors in aircraft <flyrotary@lancaironline.net>

Mat, the printer is impressive for sure.   I am not sure what you are trying to achieve with all this as I am getting the impression that like me you will lose years trying to get everything "right" . I  also have a shed full of flaps, adjustable inlets and outlets etc, all took many months to build.  At the end of the day you simply  want stable temps in the engine.  I have now gone back to a simple thermostat in the water line and the biggest  water and oil cooler I can fit.  All temp adjustments went away.  If the oil cooler is too big the water thermostat will correct that problem as well.  Just keep it simple (and cheap)  I recall Tracy'e wise words   " you are better to have a "good" (practical)  aircraft in the air, than the "perfect" plane still being modified and built". 

This is just some of my self imposed bitter experience! 

Neil.

On 1/7/2019 5:24 AM, Matt Boiteau mattboiteau@gmail.com wrote:

Buying a 3D printer has opened up this whole experimental plane game. SO much easier to autocad a drawing, then trying to fiberglass out of foam and bondo. Bonus is, easy to make changes for version 1, 2, 3, ... 15.


I'm using an CX racing oil cooler. 30 Row, 11 x 9 X 2

To create a Kays & London wedge shape for the inlet, I could of used a flat stock and called it a day. But really it's an 'S' shape to maximize equal amount of air to flow across the rad. Plus I had to make the wedge shape, turn into an 2.75" pipe opening for the scat hose. I wanted to keep the bends like a trumpet, to maximize the air sticking and following the sides without disturbance. Could of sanded and shaped the pieces out of foam for days and days.. Or punch them into autocad. 3D print the parts, then fiberglass overtop of the molds.

The last two pictures (oil4 & oil5) are how I had to make the outlet, with foam and bondo. I couldn't get good measurements around all the pipes and motormounts, so I couldn't 3D draw it. Was easier this way, to build it in place. Took 10x longer to build.

The outlet has a large 5" box to catch the expanded hot air. Then it necks it back down to a 2.75" outlet pipe. The idea is the speed the air back up before it exits. I also added a butterfly valve to the outlet, to be able to control the temps. This should help fine tune my system (inlet, outlet, exhaust, cowl air exit), by watching how much the valve needs to more to keep temps stable at different flight speeds.

- Matt Boiteau

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