The figures you supply are interesting in that they show relative fuel
consumption with different power settings. The absolute figures will
obviously change a bit for an aircraft in the air with the change on
prop loads for the aircraft flying at speed. For what it is worth in
practical terms I found the following relevant.
Using a variety of throttle and prop settings I came to the following
conclusions:
1. Despite the fact that the minimum drag speed is given as 75kts
the aircraft seems to be a lot happier in terms of angle of attack once
it is above 100kts. I doubt that there is much to be gained flying
slower than this.
2. With that in mind I used two speeds to compare fuel flows:
105kts and 120kts IAS
3. At 120kts the difference between 4500rpm and 5000rpm gave
negligible differences in fuel flow as greater throttle settings were
needed at 4500rpm.
4. At 105kts there was a 1.5litres/hr benefit from using 4500rpm
over 5000rpm.
5. Although the fuel flow is significantly lower at 105kts the
better overall economy is not much better because you fly 15nm less in
any given hour.
The engine gives better fuel flows with lower OAT so I generally found
it worthwhile climbing to 7000-8000ft in hot weather to get cooler air
into the engine. Some day I must do some comparison figures up there as
well.
Hope this is of interest.
Regards
Nigel Charles
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of
irampil@notes.cc.sunysb.edu
Sent: 04 April 2007 14:19
Subject: Europa-List: Fw: Rotax 912s Benchmark Performance
Greetings All,
I have been interested for some time in developing a set of performance
data for the Rotax 912s
as installed in my Europa Trigear. This information, provided in the
POH of all certificated
constant speed propellor aircraft is sadly lacking from Europa or Rotax
manuals.
I am enclosing the static performance data at sea level on a standard
pressure day for my engine.
The aircraft is chocked and not moving. At some point soon I hope to add
the data including TAS
airspeed at 3000, 6000, 9000 feet density altitude. NM means not
measured because I thought
higher power would jump my chocks!
Hopefully this data will allow us to make informed choices for MP and
RPM settings for speed or
economy, etc.
At this point I would appreciate comments on the data and methods, etc.
Cheers,
Ira N224XS
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