September - October - The Recreational Aircraft Association

Room with a view.
etry on the large centerline tire.
The Xtremes use an MT Propeller’s constant speed
system with settings for automatic governing and full
feathering. Europas typically install an Airmaster AP
332 three bladed composite construction propellers
with an adjustable pitch system that allows selection
of these modes: Take Off, Climb, Cruise, Hold and
Feather ($3,990 US). The system worked well in all
modes and while it does not have a constant speed
capability, none was necessary. The “hold” setting
allows pilots to manually adjust the propeller rpm to
a desired setting. The Europa three blade had a slimmer
leading edge and my guess would be considerably
better performance in terms of efficiency due to
lower profile drag and a higher solidarity ratio – but I
have no definitive data on this.
Runway Considerations
Neither type has flaps, nor do they need them for
take offs with their high lift wings. With my Xtreme,
one lifts the tail at 40 KIAS and levitates at 45 knots
in approximately 600 feet at gross weight. The turbo
versions of these motorgliders both use one hundred
feet less and climb at better than 1300 fpm compared
to my optimum 800 fpm – all according to manufacturer’s
published data. While I find the Xtremes
easily match that published data, the Europa’s take
off left 1000 feet behind us and yet it yielded a rate of
climb in excess of 1400 fpm. It is to be expected that
the Europa should out climb the similarly turbo’d
Xtreme due to its similar L/D and power while propelling
a lighter gross weight. The Europa folks were
obviously conservative in stating the rate of climb.
When John Hurst transferred control to me after
take off I lowered the nose to improve visibility and
climbed at 115 mph with 550 fpm showing on the VSI
as this provides an excellent cruise climb configuration.
Relatively speaking, Xtremes are considerably
quieter in the climb as I usually forget to turn on the
electric noise canceling feature of my headset. Visibility
over the nose is also much better as the fuselage
sits more nose down on the wing planform with
the Diamond.
In Flight
Levelling off at 5000 feet (far from the turbo’s optimum
cruise altitude) approximately 75% cruise power
and pitch were selected to provide 152 mph TAS. Control
response was good with control forces increasing
with speed and the harmony was good between axes
and pitch stability was excellent. The Xtremes have
light pitch forces but rudder and aileron are heavier.
Additionally, pitch stability in my Xtreme is close to
neutral at cruise power settings in the 121-128 mph
September - October 2007 Recreational Flyer 25