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From: Terry Seaver <terrys@cisco.com>
Subject: Re: Europa-List: What engine for my Europa?
Hi Richard,
You didn't say where you do your flying. If you intend flying at
altitude like we do around the Sierra Nevadas, you might consider the
914 the best bet.
We have a mono-wheel XS with 912S and Airmaster prop. I would seriously
consider installing the 914 or Jabiru over the 912S, given our
experiences (we have over 400 hours on the plane/engine).
Issues I have with the 912S are:
1) It shakes the whole plane when starting and stopping, causing great
stress on any number of componants. Our exhaust system is in constant
need of repair because of this. An ignition wire probably broke because
of this. Standing outside the uncowled engine and watching the extreme
travel of the shaken componants can be a real eye opener. It is not
unusual to see +2G/0G on the panel mounted accelerometer following a
start or stop. I would guess the 912S is worse than the 914 because of
its higher compression. I would expect the Jabiru to be much smoother.
2) The 912S is a little anemic at high density altitudes. At 7,000+
feet the plane has difficulty accelerating past 55 knots on take off
until the gear/flaps are lifted a little. Climb rate at these altitudes
can also be lower than I would like.
3) The mixture becomes rich at altitude, negating the fuel economy
advantages of flying at altitude. The 914 is altitude compensating, and
I assume the Jabiru has a mixture control (?).
4) Although the Rotax is claimed to have a TBO of 1000 hours or greater
it is recommended that the gearbox be removed and sent in for check out
every 300-400 hours. There have also been suggestions that idling the
912S down to 1400 rpm can cause damage to the gearbox due to rough
idling. We idle our engine at about 1700-1800 rpm, which make the
landings a little hotter with the additional idle thrust.
just my two cents worth, regards, Terry Seaver A135 / N135TD
>>>>>>>>>>>>
Hi Terry,
I have just a few comments that not all 912S installations behave in the same
way.
When I start or stop my 912S, it does so quickly - no shake, rattle or roll.
Perhaps the prop weight and inertia are factors, my Whirlwind 2 blade prop
is very light at 9 lbs. I have the standard factory Lord MT04 rubber vibration
mounts.
I cannot testify regarding high density altitude take-offs but I have
demonstrated
200 ft/min climb rate at 16,000 ft at a take-off weight of 1312 lbs during
a service ceiling check. I agree that the 914 will definitely give one better
performance and a higher comfort factor in the Rockies and the Sierra Nevadas
but for owners who are usually east of the Mississipi, the 912S should serve
very well.
I am sure you are correct that the mixture does become rich at altitude but
there
certainly is some altitude compensation on the 912S. My typical full
throttle/5500
rpm fuel flows at 2,500, 5,000 and 10,000 ft are 6.6, 6.2 and 5.5 US gph.
My fuel economy also seems to be quite good at altitude and the following
is an extract from a logbook entry on 12.12.03 which was the record of a careful
3 cornered run at 10,000 ft, 5500 rpm and full throttle. "Average airspeed
= 124 kts indicated, average groundspeed = 141.7 kts per GPS (=163 mph), average
fuel flow = 5.5 US gph = 29 miles per US gal." (Take off temperature at 840
ft was 6 deg C, so it was a cool day.)
Cheers, John
N262WF, mono XS, 912S, Whirlwind hydraulic C/S prop, factory speed kit fairings,
370 hours
Mooresville, North Carolina
704-664-4167
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