Engine considerations
de: Thomas Scherer, Builder # 81, Detroit, Michigan, USA
re: engine considerations
Hello to everyone on this electronic council.
Since last week now, I have received all the parts for my plane - I
cannot blame the company for late pieces anymore, the duty to finish
the plane lies all with me now. There is Stage IV and the instruments
as well as a Warp Prop and Rotax 912.
A building-status report will be another message; I wanted to give
my penny worth regarding engine considerations for the EUROPA.
During the 1.5 years of the project I went through hot and cold baths
of thoughts including that '914 Turbo with a one-of-a-kind color,
active matrix engine monitoring system' or the 'I weld my own exhaust
type auto-conversion 180 hp turbo engine for half the 912-price'.
Not to forget that variable pitch prop that revolutionises prop
efficiency.
Besides me stands now a standard Rotax 912 with
a black WARP Drive three blader - ground adjustable.
One turning point element for me was a sentence of Don Dykins in the
Europa's Aerodynamics book speaking about that almost-laminar airflow
for a speed range of 120 - 150 Mph. I learned from that sentence that
more hp does not linearly translate into more speed, but might bring
you into a unefficient, maybe more instable range above the design
speed range. The Europa is not a BD-10 but a wonderful airplane
designed for 120 - 150 Mph.
Comparing the Europa to a Porsche, I note that it takes 310 hp
to propell 2 people and a teethbrush to 150 Mph, while the Eurpa does
that on 80 hp. I get quite gratefull towards Ivan and Don when
I consider this.
The American magazines do emphasize way too much speed and numbers
('The XY stalls at 38.5 KIAS and that is a non-event') instead of
airplane feel and utility. The articles create dreams in people. Too
many companies live off those dreams (did you see the ad for a kit-
built Jet engine ? Excuse me !! 50000 rpm and highly flammable
liquids in a basement ?). And everyone who has flown the Europa
knows that it feels great.
So I have here the 912 and it makes me feel safe - it is an engine
that is certified and has proven itself on many platforms. The Europa
is designed around it. The 914 seems too young and unfinished and the
extra 20 hp are not worth 4000 $ to me.
Warp Drive will be coming out with a variable pitch hub for next
Sun & Fun. It will be electric (for those with the Vac pump) and
will allow feather (for the Motorglider guys). They guessed a price
of around 1700 $ when I asked.
By the way, the activ matrix display engine monitoring system gave
way to 4 gages from Westach and VDO.
Happy building,
<Thomas>
/ex
y
|