From: "Stephen Izett stephen.izett@gmail.com" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] OIL
Date: Wed, 27 Jun 2018 08:06:01 +0800
References: <list-11305477@logan.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
In-Reply-To: <list-11305477@logan.com>
Message-Id: <3E0F3D70-F270-47F8-93C6-72BEF6FBB228@gmail.com>

Thanks again Lynn for the =E2=80=98good oil=E2=80=99

I would value your thoughts on our oil cooler?
We have a Mazda cooler but not sure which model its out of. Thought it =
was one of the turbo models.
I=E2=80=99m pretty sure it measures 11 x 8.75 inches by about 2 thick.

My question is - lets say that the rest of the oil plumbing is OK - what =
advantage as a percentage do you believe there would be in exchanging it =
for a Fluidine of the same dimensions?

Thanks again.

Steve Izett


> On 27 Jun 2018, at 3:21 am, Accountlehanover lehanover@aol.com =
<flyrotary@lancaironline.net> wrote:
>=20
> Subject: Re: [FlyRotary] Re: Oil
>=20
> There are some very thick books about oil and water cooling systems. =
There are some engineers who spend whole lifetimes on this. I am not one =
of those. But I have learned quite a bit, mostly the hard way.
> So here is some of that. No flowing system likes sharp corners. Air, =
water or oil. Do not use drilled 90s for fittings. Use sweep 90s and =
45s. When building coolers you find that the chilled media tends to =
cling to the tube, causing a loss of efficiency because the hotter media =
is then being insulated from the tube walls.
> So, manufactures tend to use fewer flat tubes (less money) and add =
cheap fixes to get back up to minimum performance.  Violent tribulation =
is required to keep mixing the cooled media with the hottest media. So =
you see a collection of odd things in the tubes. Mazda uses a Twistoflex =
watch band lookalike. Others a cross hatch pattern in the tube walls. =
Fluidine is the class of the field with their inside out radiator =
design.
>=20
> Every system has one sweet spot for every flow rate, every =
temperature, every pressure, every media. You can track that sweet spot =
with a thousand sensors and a lap top. And cooler designers do just =
that. Everything affects everything.
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> Rotaries run best (Best power) when the oil is below 160 degrees. =
(Daryl Drummond) . High rotor face temps
> tend to expand the fuel air mixture entering the chamber quickly, =
killing off more of the incoming flow. Bad at low RPM. Less bad at high =
RPM. We raced at Grattan Michigan with the temps at 30 degrees.  Water =
thermostat in place and 2/3 of the radiator taped off. All of the oil =
radiator taped off.  Ran the race with water temps at 120 degrees and =
oil temps at 150. The thermostat had a 1/8 hole in the edge to let air =
bubbles through. This is not to suggest that 1/8 inch hose is adequate =
for cold climates.
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> In olden times when we still used the stock pump we opened the lateral =
gallery plug and took the oil out of the block right there. Going back =
into the block at the stock rear Banjo fitting. And the lateral gallery =
in the front iron to the front main bearing. Later with the massive =
external pump we still fed that front bearing with its own supply. We =
did not plug the dowels that connect those two location.
>=20
> Mistral found the oil pickup tube and bug screen to be a problem. The =
anti vortex disk diameter is stupid small.
> And so then is the bug screen. I removed the bug screen and added a =
big flat disc to the end of the tube.
> I built up the back side with braze and ground the sharp edge down to =
look like a trumpet bell. The bug screen would filter out a mouse but =
not small enough to stop the grit that will kill the pump or bearings. I =
never missed it.  Mistral cast up a new pick up tube but without the bug =
screen. they used a baffle plate between between the  pan and engine. It =
had large areas of screen to perform the bug screen job.
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> The object of higher oil pressure is move oil out of the wedge more =
quickly so as not to damage the very soft bearing material.=20
>=20
> Low oil pressure at idle is usually not a problem. No bearing stress =
at all. 5 or 6 pounds is fine. Minimum loaded pressure not below 60 PSI =
while looking for nearest to see where you 80 PSI pressure went.
>=20
> If you or some engine builder took out the springs and balls from the =
crank then low idle pressure cannot be corrected. Used only for constant =
 high RPM in racing. You can put them back in at over haul in about 15 =
years. Keep in mind that this advice is free. And, worth every penny.
>=20
> Lynn E. Hanover
>=20
>=20