Europa
trigear - handling report
from
www.pfa.org.uk
1. This aircraft was fitted with a Rotax 912 and the
Arplast electrically controlled variable-pitch propeller. A medium wt/mid
CG aircraft was flown throughout the PFA conversion to type. Although the
trigear Europa is in many ways a simpler aircraft to fly during the
Take-Off and Landing phases than the Monowheel version, it still exhibits
many similar characteristics to the Monowheel aircraft. Principally, the
very powerful all flying tailplane still provides ample opportunity for
PI0 in pitch whilst in contact with the ground. This is partly due to the
centre of gravity being relatively close to the main wheels and thus
providing plenty of scope for the nose wheel to bounce off a rough surface
and into the air. However, this is also exacerbated by the combined
inertia effects of the flight control system itself (counterbalance
weight) and the pilots arm. The effect of a fully aft CG position was not
investigated. Once airborne the aircraft is similar in handling and
performance to the Monowheel. The following significant differences in
technique and handling were noted:
2. A fully castering nose wheel allowed manoeuvrability
in very confined spaces with use of differential toe brakes positioned
between the rudder pedals. Taxying across grass or undulating surfaces at
more than a few knots created a very uncomfortable pitching motion as the
aircraft tends to bounce off the nose wheel and which causes feedback (due
to the mass counterbalance) through the elevator exacerbating the motion.
3. Take Off was completed with flap selected to 10
degrees and a fine propeller pitch setting (4.5 units).
During initial application of power and until the
aircraft has reached around 10-20kts, judicious use of differential
braking was found to be the most effective means of keeping the aircraft
tracking straight. Thereafter, aerodynamic effectiveness is quickly gained
and control transferred to the rudder pedals. The aircraft was allowed to
accelerate to around 50kts before about 0.5 inch of rearward stick
movement was required, just enough to allow the nose wheel to part company
with the ground. During the ground roll it was essential to steady the
hand against the thigh to help prevent inertia acting as a forcing
function to the aircraft's natural susceptibility to pitching motion (as
the nose wheel bounces along the surface). Once clear of the ground, the
aircraft accelerates much more rapidly than the Monowheel Europa (with
Full Flap) and settles down quickly into a comfortable climb at 80 kts.
4. With the speed back at 80 kts the final turn was
commenced with 10-15 degrees of flap. This provided enough drag to
commence descending at a reasonable rate without risking the possibility
of a Flap overspeed in turbulent conditions. Rolling out on the final
approach Full Flap was selected and the speed stabilised at 70 kts. Prior
to landing, it was again found necessary to stabilise the flying arm to
prevent any self-induced pitch oscillation immediately after touchdown.
Even the slightest fore/aft movement after touchdown creates an
uncomfortably large pitch input and should therefore be avoided.
|
home
sport &
experimental aircraft
Aeronca C3