The following is some engine trivia for the Europa builders out there not ye
t having sourced an engine: Having spent yet another year at Osh attempting t
o educate myself, on the subject of engine choices I have come to the follow
ing personal conclusions fwiw (my opinion only, "you mileage may vary" etc.
:-)
1- The only feasible/reliable geared engine I saw at the show is the Rotax 9
-series with its thorough engineering to deal with the resonant issues with i
t's newer (since the 100hp) 30deg dog clutch and additional integrated pack-
clutch, set to ~500lbs. I have attached a few cut-away pics of the gearbox o
f it's clever dense packaging). The auto conversions, with their solid engin
e cores have a weak link in the gearboxes - the simplistic rubber bushings..
.. a design that I do not believe is adequate. The European BMW two-cyl with
gearbox appears to now have some good in-service experience, but was not at
the show to check out, and it's gearbox design is still unknown to me.
2- For direct drive engines, there are two feasible designs:
- the ULPower engines: a turbo'd small short-stroke low compression fou
r cyl, or a naturally aspirated larger long-stroke higher compression four c
yl - either would be lighter than the 914 installation.
- The still unproven but incredibly light and low parts-count flat-head w
ater cooled designed D-motor: either a turbo'd four cyl, or the 6 cylinder,
with the 4 being lighter than the 914, and the 6 cyl being about the same w
eight as the 914, albiet not as good at altitude. A turbo'd 4 cyl would get a
round the flat-head's inherent lower compression ratio, and should be good p
erformer.
The 915 is too heavy for the Europa (215lbs as per the factory rep), and wit
h an even longer gearbox putting that CG even further forward it is not a go
od option for the Europa, if one wants FI and Turbo. The smaller ULPower en
gine would be terrific turbo'd, but the factory is not wanting to deal with c
ustomer turbo customer support head-aches and reluctant to provide custom FI
maps. That leaves the D-motor..... which I will be watching carefully over
the next year or so before I'll need to make a decision.
Chatting with Airmaster at the show, a geared prop for the Rotax would be 1-
2k$ (~10%) less expensive (and lighter) than the equivalent prop for the dir
ect drive engines which have to deal with the increased engine pulses and ha
rmonics.
FWIW,
Cheers, and blue skies,
Pete
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