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Introduction
With the Caprise, Alliance, Fashion and Evolis, ZN
Line
has a complete line of pattern planes, which cater to every preference.
For me, a 2000 season with an Alliance has persuaded me to try the latest
model designed my Arnaud Poyet, the Evolis XL. In effect, the fuselage
has soft and fluid lines, which are sufficiently voluminous, a fixed gear
which has become very fashionable as well as a reduced wingspan so as
to improve the snap rolls, which will become the foundation of future
schedules.
 The
Kit
No surprises for seasoned F3A veterans while newcomers won't be disappointed
either. The fuselage, gelcoated white, is superbly finished and light,
with just some light sanding on the center seam needed before painting.
You certainly won't need to paint over the white gel-coat if you want
to save some weight. The cowling is of similar build and fits perfectly
on the fuselage. The two pieces are reinforced by foam as used before,
not just for strengthening, but also to absorb noise by eliminating resonance.
The wing, stab and rudder are balsa-sheeted, foam. The new grade of foam
is used, which is denser than in conventional models, but the honey-combing
minimises any gain in weight. Wood is used for the engine mount, stab
mount, leading edges and edge facings, all being of excellent quality.
It's noteworthy that the stab is not only detachable, but also independently
adjustable. The wing servo cavity is catered for and all flying surfaces
have been separated. There are no cavities for the landing gear as you
can see. The Evolis XL is supplied by an excellent carbon fiber
landing gear and fiberglass spats, which will accommodate wheels up to
65mm (for grass runways).
Information
All joints made on the fiber must be a combination of slow epoxy and micro
balloons, so as to prevent deformation of the fuselage that may arise
from having used fast-drying epoxy. Each element should also be dry-fitted
before applying adhesive. Don't forget to sand the inside surface of the
fuselage with rough sand paper where any joints will be made.
 Engine
Mount
The engine installation consists of a forward support for the nose-ring
and a rear support for the engine mount. I chose the ZN
Line
mount designed by Arnaud Poyet, which is not only light, but also very
easy to mount(More information @ Technical
Section). While you could use the plywood plates that were furnished,
I chose to use a sandwich of carbon fiber / nomex honeycomb in order to
save weight. For the servo mount and fuel tank, you can also make a similar
plate, either using a sandwich of carbon and 3mm-thick balsa, or fiberglass
cloth of 80g/m2 and nomex .
You can also simply purchase the carbon/nomex tray offered as a ZN Line
accessory. Make sure you use slow-dry epoxy when installing the plate
as quick-dry epoxy may deform the fuselage as it cures. The tuned pipe
mounting is very simple (Laurent Lombard's idea): Just two slices of silicon
tuned pipe coupling which are fixed to either side of the tuned pipe.
The slices themselves are mounted to a plywood plate, which also serves
as reinforcement for the rear wing bolts. I've used this system for the
past 3 years and have yet to encounter any trouble. In front, a Hattori
manifold is used with an MK mount.
Finishing
For the fuselage, you can use the white gelcoat as the base colour, which
will certainly save some weight. The flying surfaces are covered with
Oracover, which coats the surfaces very well.
 Servos
For throttle, I used a mini-servo mounted behind the firewall, taking
care to keep the actuating rod as short as possible. Conventional pull-pull
rudder cables are used as well as 2.5mm push rods for the ailerons. However,
I used a twin-servo set-up for the elevator, using two mini-digital servos
in each stab half, and actuated by 2.5mm rods connected to ZN Line aluminum
horns.
The length of the elevator servo extensions
didn't cause any problems, at least with my Futaba set-up. You can install
shields if you wish, but I've never had any problems.
 Radio
I threaded the receiver antenna through a sheath mounted in the fuselage
(glued in place before assembly). It's been 4 years that I've used this
method, and even with the Kevlar/carbon fuselage and long extension cords,
I've never encountered any problems.
For throttle, I used a Futaba 3101. For rudder, a Futaba 9402 was used
(a minimum torque of to 7kg should be used). A pair of Graupner DS3728
(3.6kg) was used for ailerons while the elevator is actuated by a pair
of Graupner DS3328 (4.1kg).
For added security, I use a dual 600mAh
5-cell battery setup mounted behind the firewall (for CG reasons). In
any case, do remember to test your batteries before every flight under
a load of 300mAh.
Setup
Engine: YS 140 Limited
Weight : 4.3kg
Propeller : APC 15.5 x 12W
Radio : Futaba 9ZAP
Low Rates :
Aileron : +15mm -13mm (30% Expo)
Elevator : +10mm (20% Expo)
Rudder : 25 degrees (40% Expo)
High Rates :
Aileron : +/- 28mm (80% Expo)
Elevator : +/- 20mm (80% Expo)
Rudder : 45 degrees (60% Expo)
CG
You can balance your Evolis between 280mm and 270mm from the trailing
edge according to your preferences. I fly at the 270mm position, which
suits me fine with the batteries behind the firewall and no lead required.
Of course, if you use the MK bellcrank elevator assembly, you will need
to move the batteries rearwards to compensate.
 Flight
Such pattern ships are designed for F3A competitors with many years of
success, so we'll dispense with the basic take-off and landing characteristics
of the model. The first thing you'll do to set-up the model will be to
do alternating knife-edge passes to check the stab incidence. You'll also
be adjusting the deflections and exponential to your liking. There is
very little rotational inertia (a smidgen of aileron differential remains
necessary though), which allows extremely precise snap rolls, both in
positive and negative directions. Some minor pitching to the belly was
quickly resolved with some 5% pitch-up on rudder application. But the
point and slow rolls were extremely precise and needed little correction
otherwise. Spins were also sharp, thanks to the low rotational inertia.
Cross wind behaviour is aided by the effective
rudder and the light weight, which also allows for `soft' flying in calmer
weather.
I'll return to the knife-edge flight again,
because in normal F3A conditions, very little rudder deflection is needed,
hence the mixing as mentioned above is not really necessary. So for slow
and point rolls, there'll be a very slight amount of rudder movement.
You will notice the pitching when doing perhaps a knife-edge loop at low
throttle and with a small radius. Thus, if you don't indulge in such fancy
maneuvers, you won't need the mixing.
A little note about the fixed gear: it's
a real advantage for those who don't fly from smooth tarmac runways. Even
with an unkept grass strip, it's unlikely that your aircraft will nose
over at each landing.
Conclusion
So, you now have a model of the highest level, with the results of Pascal
Nowik and Arnaud Poyet speaking for themselves. With this model, you won't
have any more excuses if you fly poorly (at least for me!) and you can
be sure of having a top-class model suitable for the next generation of
F3A schedules. - Frederic
Verroust
Note: Many thanks to Stanley Chan, Singapore National F3A Champion and
my brother, for helping in the translation of the above text.
Check out
Gianluca Crino's
Evolis XL review for another read.
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