.<<...> BMW.....torsional vibration proved to be a too difficult
> problem to overcome after exhaustive development work....>>
Nigel,
Please note that when running the BMW did NOT suffer from torsional
vibration problems. Rather, it had the same starting difficulty that the
912S sometimes has (only more extreme) which, by consensus of this forum, is
not torsional vibration (although I don't agree with that).
Rgds.,
Duncan McF.
----- Original Message -----
From: "nigel charles" <nigelcharles@tiscali.co.uk>
Subject: RE: Europa-List: ENGINES!
> <nigelcharles@tiscali.co.uk>
>
>>Thats easy!
>>> Get the 140 hp Dual Port Fuel Injected EA81 with redundant injection
>>>here:<
>
> Very easy if you want to substitute baggage capability for engine
> weight. The extra weight also means the battery has to be in the tail to
> keep the C of G within limits. This increases the pitch inertia which
> degrades the handling characteristics slightly.
>
> For those who are new to the forum and are trying to make an engine
> choice the following might be a useful summary:
>
> Subaru - too heavy, NSI (the company producing the engine/gearbox
> package) have a poor customer relations record.
>
> BMW - nice engine but torsional vibration proved to be a too difficult
> problem to overcome after exhaustive development work.
>
> Mid West Rotary - very smooth and light but excessive fuel consumption
> and very difficult to set up to run smoothly at all rpm's.
>
> Wilksch Diesel - lovely engine with many original design patents. It is
> very fuel efficient and cheap to run due to much cheaper jet fuel. This
> is an engine to watch in the future for the replacement of
> Lyco/Continentals but it is just too heavy for the Europa. The radiator
> adds significantly to the frontal area which may increase drag.
>
> Lyco/Continental - too heavy and high fuel consumption.
>
> Jabiru - the only workable alternative to the Rotax for the Europa. True
> it is simpler. If you want a simple aircraft you would probably not have
> chosen the Europa in the first place. Although it has a higher power
> output it is at 3300rpm which is too high for the prop to use
> efficiently so the performance advantage is negated. Being aircooled the
> fuel efficiency is slightly down on the Rotax. Some cooling issues were
> apparent from the cowling mods seen on early aircraft. It definitely has
> a price advantage which is the one area which lets the Rotax down. If I
> was cost limited I would sooner spend it on the engine rather than
> expensive avionics.
>
> Rotax - still the most suitable engine for the aircraft if rather
> expensive. As Ivan Shaw said in the early days of the Europa 'there is
> more work in developing the engine for the airframe than designing the
> airframe in the first place'. The P51 argument would be relevant if
> there was an engine that was significantly more suited to the airframe
> but so far this is not the case.
>
> Choice of versions of the Rotax
>
> 912 - very fuel efficient but a little underpowered for the Europa
> especially at max weight with high density altitudes. Using a VP prop
> helps to extract maximum power at take-off without affecting cruise
> performance.
>
> 912S - the extra 20hp make all the difference. Probably the first choice
> for most Rotax users. Make sure the higher power starter is installed to
> help prevent kickbacks on start due to the higher compression ratio.
>
> 914 Turbo - yet more performance but at a price and increased
> complexity. Probably the best engine for those who regularly operate at
> high density altitudes. However the 912S with a VP prop will give
> adequate performance up to density altitudes of at least 10,000ft and
> will comfortably exceed Vno at low altitudes.
>
>
>
|