Hi Jerry:
I do have a very specific question to the sense of use of the
Arplast VP propellor together with the Jabiru 80 Hp aero engine. As
you probably know, its direct drive rpm is 3300 at max power and
3100 sustained. Would the Arplast prop still be as efficient as
at 2500 rpm as most Rotax users have or will there be a
gain/loss?
I assume a smaller diameter prop will have to be found and also,
maybe a 2-blade prop option could be possible for those pilots
wanting to invest into the glider wing option of the Europa
(one blade less resistence to airflow while gliding...
Let me know. You might like to share the answer also with our forum
if you like.
Answer
Our VP propeller is not suitable for the Jabiru installation at present.
Although there be be suitable development soon.
We have supplied many propellers for use on Jabiru powered aircraft and to
date the results have been most promising with our propellers performing
better than others except perhaps on very low speed aircraft on which we
may try alternative options later.
The Jabiru engine is better suited to either a smaller diameter propeller
or fewer blades because the the blade speed is that much greater.
However - The higher revving engine may have advantages at higher speeds
but some disadvantages at lower speeds. Also note that we expect the
advantages of variable pitch to be less pronounced on the Jabiru engine,
indeed many users may decide the cost, weight and complexity are not
justified on this installation. Time will tell????
I am interested to know how the Jabiru / Europa installation is
progressing.
For those interested in the glider wing option I can add that we have
recently supplied a two blade Arplast propeller for use on an RF4D
motorglider powered by a 1600 VW engine. Top speed is currently 147 kts
corrected for 1013 mb. Some fine tuning still to be done and we may yet see
the magic 150 kt.
Finally - Arplast are refining some small improvements to the VP propeller.
These improvements should improve the overall flexibility of the design and
make it more suitable to a wide range of installations. A small price
increase is will accompany the improvemenets. The overall design of the
propeller remains unchanged but the developments should simplify
installation.
Jerry
Flying Hi - Wish I was
jerry@flyinghi.demon.co.uk
http://www.avnet.co.uk/touchdown
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