Nigel, Ron, Gilles, Ira and all,
For instance I much appreciate your valuable interventions.
Using water/glycol or Evans was and still is a choice
But let's make a statement. We have the performing engine and we have the
fixed configuration with cowlings and radiators. The engine has three
cooling elements: air, oil and coolant. Oil and coolant temperatures are
regulated by air flow thru the radiators. Air flow is dependent of ducts,
speed and propeller wash. Not so simple as at a given outer temperature all
is in the limits when cruising at more then 110 knts. The discussion about
Evans or water/glycol may give a difference of about 10C. But for the same
configuration with a difference of temperature between winter and hot summer
of 40C and a take off speed of 60 knts at full power creates the problems.
With 3 liters of oil and 4 liters of coolant we have no margin and no
buffer. Until we don't find to regulate and control from the cockpit this
temperatures we canot climb at the 1000'/min rate in every season. Let us be
humble and say that the cowlings are of a very poor design. But we build an
experimental airplane and we are proud of it. I think that I can find in
Ron's approach a stimulation to continue the experiment by making several
small changes until we succeed. And for my results you still have to wait.
Kind regards,
Karel Vranken, # 447 XS mono 912ULS Airmaster AP332 now only 35 hours.
----- Original Message -----
From: "nigel charles" <nwcmc@tiscali.co.uk>
Sent: Saturday, May 05, 2007 8:45 AM
Subject: RE: Europa-List: Re Coolant Coice
>
>>Which is why I am just modifying the air duct exhaust with
> a temperature controlled 'cowl' flap. <
>
> I have been down this route on 2 occasions once with a Classic cowl and
> once with an XS cowl. It is normal to control the exhaust rather than
> the inlet air which is what I did in both cases. Even with the outlet
> for the XS cowl being fully closed it made little difference to
> controlling either oil or coolant temperature. The only flap I have seen
> work really successfully controls the inlet air. The design uses a flap
> which can be raised to close off airflow whilst airborne or lowered on
> the ground to encourage increased airflow.
>
>
> Nigel Charles
>
>
>
|