I have the stock Europa cooling duct with the oil cooler lowered to the
bottom of the cowling. As Gert suggests below, all gaps are sealed well,
including the bottom of the oil cooler to the cowling and the sides of
both coolers to the aluminum duct.
I flew last week to Death Valley with a friend in the right seat. When
we departed furnace creek(L06) the OAT was about 90 F. The climb from
200' below sea level to 11,000' at 90 to 100 knots indicated showed oil
temps up to 240 F and the Evans coolant 230. CHT is always within 10
deg. of the coolant.
I have been climbing most of the time at airspeeds around 100 knots and
100% (34"map) which yeilds a healthy climb rate. The temps inside the
cowl have gotten high enough to deform the spark plug indicator labels.
I wraped the exhaust pipes, but I'm not sure if that helped really
because I don't have the cowl temps monitored.
The OAT should exceed 100F today. Whew!
Best of luck, Kevin
Mono intercooled 914 Airmaster prop
----- Original Message -----
From: Lisbet og Gert Dalgaard
To: europa-list@matronics.com
Sent: Saturday, June 05, 2010 4:22 AM
Subject: Re: Europa-List: Cooling issues, once again!
Be 100% sure that no air are bleeding out through gaps around your air
baffles! Just a little gab is enough to spoil your day.
Regards Gert
OY-GDS / mono / 914 / 500 hours
Den 05/06/2010 kl. 12.28 skrev Frans Veldman:
<frans@privatepilots.nl>
Gentlemen,
Although my initial cooling issues have been improved upon, I'm not
satisfied at all with the cooling of my 914.
Now, with increasing ambient temperatures, I have to severely limit
my
climb outs. Cruising is ok. During climb, both the water temperature
and
oil temperature approach the red line, more or less at the same
time.
Water temperature recovers faster than the oil temperature after I
power
down. At this time I can barely make it to circuit height and then
have
to level off, build more speed, and then limit my climb with 200
ft/min
until I'm in cooler air. The engine has now 32 hours on it, so it
might
still improve somewhat further, but I don't expect miracles from
that.
I had to do something.
First I made an additional exit in the cowling, under the turbo,
hoping
to provide more airflow. Whether the airflow in the cowling improved
I
don't know, but it had zero effect on the water and oil
temperatures.
Temperatures inside the cowling seem to be ok anyway, no discoloured
spark plug indicator labels (still bright yellow), no melted
tie-wraps, etc.
My conclusion was that the problem is not in cooling of the cowling,
but
somewhere in the efficiency of the radiators.
So then I built a new radiator inlet, somewhat larger than previous
one,
with a lip to avoid digesting the boundary layer and making sure the
inlet receives ram air, angled straight into the airflow, and with a
diffuser for which I copied a profile out of a famous book.
It was no improvement over my "free style" sleeker inlet and
diffuser.
None. Very frustrating, as I ruined my nicely shaped and painted
original inlet for this.
I need to do something, but to avoid ruining again something in
order to
solve this problem, I need to hear some experiences:
1) A shroud over the cylinders. I don't have it, but instead I have
two
naca ducts in the upper cowling, curved down to release air aimed at
the
cylinders.
Has anyone ever tried whether the Rotax shroud (or home made shroud)
makes any difference? Sure, it will cool the cylinders, but does it
have
any effect over the water temperature and/or oil temperature? Or is
this
again going to be a loss in time and effort?
2) In my setup the oil cooler receives exit air from the water
cooler. I
know there is a "trick" mentioned in the build manual for hot
climates
to lower the oil radiator 2 inches to receive cold air instead of
warm
air, but I didn't opt for this as I don't consider our climate as
extremely warm, and in winter the oild could actually get too cold.
Has anyone tried both options, and did it make much difference?
Also,
did it have any influence over the water temperature? Relocating the
oil
radiator will be a large project, and I fear that after that I will
still have to limit my climb outs to avoid the water from boiling.
Yesterday on the airfield I took a closer look at the Rotax 914
equipped
Dimona, which is used by the glider club to tow all day long
gliders,
with full power at 50 knots, in all ambient temperatures. They never
have cooling problems.
What I saw was shocking. The water radiator is fully exposed to the
airstream, no diffuser whatsoever, it is just part of the cowling,
as if
someone took out some skin of the cowling and fitted the radiator in
the
resulting hole. The oil radiator is mounted in an angle behind a
naca
duct (I was taught that a naca duct does not provide ram air and
shouldn't be used for cooling a radiator?). Both radiators just dump
the
warm air inside the cowling! It can't be easier than that.
Then, at the bottom, the Dimona has a cowl flap which just opens the
cowling to dump *all* air overboard. If it is closed, all radiators,
as
well as all cowling ventilation, is blocked.
How can this system, which looks less sophisticated than our system,
while violating all rules and knowledge, work so well?
Anyway. At the moment I'm grounded, can't fly like this, and after
spending a week trying to improve things with zero effect, I'm out
of
options and I'm inclined to leave the airplane in the hangar and
find
another hobby. :-(
Seriously, what should I - The Europa-List -->
http://www.matroni &n -
&nbs -->
http://www.matronics.com/co================
|