Jim;
I have reported here 3 or 4 times before
that I have measured the flow through my engine and the dyno cooling loop
provided by the engine driven pump; and it correlates quite well with what I
calculated the flow requirements to be for something near optimum for aircraft
use.
We have also repeatedly been over the
issue that; all other things remaining the same, the higher the flow rate the
better the cooling. Lower flow simply means higher delta T, and lower
average radiator temps. No, we don’t know what the minimal needs are in
regard to keeping thermal stresses from being an issue in the engine.
And I agree that whether BMW wants to
design for, and use, and EPW or not is irrelevant to our application, and the
exchange have mostly been in the spirit of fun.
I am not “against” the use
of EWPs in our airplanes. My position is simply that unless you have a “need”
for configuration reasons, there is no technical reason to enter into that
realm of whatever the unknowns are for this application.
Al
-----Original
Message-----
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Jim Sower
Sent: Sunday, March 20, 2005 12:41 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: BMW and
EWP
Wasn't someone talking
about the 12-16 GPM his EWP was pumping through his [not running, no EDWP]
engine? Assuming 2-3 gal capacity, that circulates every bit of coolant
through the system 5 or 6 times per minute. That's an entire cycle of coolant
every 10 seconds or less. That sounds pretty fast to me.
Does anyone actually know what the
flow through a rotary is with EDWP? I mean, like measured (the other list can be relied upon
to calculate stuff). Just
as important, does anyone actually know
how far open/closed a thermostat is in our applications. I know some
folks don't have thermostats installed. Is it possible that EDWP might be
circulating coolant so fast it doesn't have time to cool off much in the
radiator or heat up much in the block? That the same system would work as
well at lower flow? Or something like that?
It seems to me that all this quibbling about Beemer power levels on the
autobahn ignore the obvious fact that as Leon has attested, EWP works quite
well on the race tracks of Oz. I would hazard a guess that the stress on
the system (WOT nearly all the time, maybe 1/3 the Q through the cooling
system, SL summer temps rather than cruising much faster (3x the Q) at 80% at
much higher/cooler altitudes) would hold a lot more water than a bunch of
Beemer marketing brochures.
The other list is forever making pronouncements about what will or will not
work. Their math is impeccable.
The premises they operate from are not
Is it not possible that we are overlooking or underemphasizing some important
factor? That the hybrid (EWP and
EDWP) systems we have online now are distorting the data? Leon's
experience cannot ignore any of the factors. Our estimates can ignore as
many as we want to (or are unaware of). I can't help but think that a
little morel hard data gathered from a purely EWP system will put a lot of the
controversy to rest.
A flawless line of reasoning,
based on a false premise leads us
right through the lookin' glass
...
Jim S.
Leon wrote:
----- Original
Message -----
Sent: Sunday,
March 20, 2005 5:45 PM
Subject: [FlyRotary]
Re: BMW and EWP
In a message dated
3/18/2005 11:24:08 PM Pacific Standard Time, ALVentures@cox.net
writes:
Let’s
say the rated hp is at 4800 rpm. The only time you approach rated power with
this car is WOT at 4800 rpm at sealevel on a 60F day. How long would you
ever sustain that condition.
Al
Al, How about
100mph for 20 minutes on the autoban?
Bill
Ah-h-h-h;
you’re getting close now. That‘s probably about 80%
power. But you’d probably have to stop once to pay a toll, and slow
down for the Opal that’s driving in the left laneJ. Or maybe they
don’t sell the EWP version in Germany.
All