Having carried out a number of first flights on 912 powered Europas I would
offer the following observations.
Prior to first flight I insist on carrying out at least a full power run for
2 minutes on the ground. Full power meaning 5800 RPM (throttle full open,
RPM controlled by prop pitch). If a fixed pitch prop then full throttle
will do.
Such a run achieves two things. Firstly it demonstrates the engine
performance and fuel flow adequate to get the aircraft airborne and into a
safe downwind position. Secondly it demonstrates adequate cooling to enable
flight without exceeding any limits. After shut down heat soakage from
engine to coolant may well cause the water to boil. Pressure is built up in
the cooling system and the system may well vent itself out of the water
header tank. This demonstrates operation of the pressure relief valve and
integrity of all your joints. After the run (and cooling), top the system up
and check tighten all hoses.
During such a ground run I would expect the oil and water temperatures to
get very close to or equal to limits. Subsequent flights will demonstrate
that cooling is adequate and as the engine settles in will progressively
improve. Assuming no other problems the temperatures will continue to slowly
fall over the next 50 to 100 hours of running.
I hope this provides some guidance as to what to expect on early runs and
flights.
Pete Jeffers
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Frans Veldman
Sent: 30 October 2009 12:27
Subject: Re: Europa-List: Coolant overheating
Kingsley Hurst wrote:
> Not that I can speak from experience, but I'm wondering if you might be
> better off getting the aircraft into the air where you can properly load
> the engine to run the rings in and at the same time generate more
> cooling from the airflow. Once the rings are properly bedded in, the
> heating experience on the ground might be quite different from what it
> is now.
That would be an ideal solution. However I presume that any test pilot
will want to see this thing running at full power on the ground for
several minutes, before taking it out for a test flight. So, I have at
least get to that stage. I haven't dare to test it yet, but I would be
surprised if I can run it for two minutes at full power at the ground
without overheating it.
Frans
Checked by AVG - www.avg.com
07:38:00
|