From: "Stephen Izett stephen.izett@gmail.com" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] Re: OIL
Date: Wed, 27 Jun 2018 08:24:53 +0800
References: <list-11306141@logan.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
In-Reply-To: <list-11306141@logan.com>
Message-Id: <96936E37-F35D-451B-935C-F170987B3B17@gmail.com>

Perhaps I should have asked.
What temperature difference do you think a fluidyn cooler would make?
Steve

> On 27 Jun 2018, at 8:06 am, Stephen Izett stephen.izett@gmail.com =
<flyrotary@lancaironline.net> wrote:
>=20
> Thanks again Lynn for the =E2=80=98good oil=E2=80=99
>=20
> 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.
>=20
> 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?
>=20
> Thanks again.
>=20
> Steve Izett
>=20
>=20
>=20
>> 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.
>>=20
>> 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.
>>=20
>> 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.
>>=20
>> 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
>=20
>=20
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