The Mosquito Hang Glider power pack
by
Joel Letouzey
Satisfaction and Self Sufficiency with a Motorised Harness.
I've
been a hang glider pilot since 1979. Having endured long drives to mountain sites or towing
bases long enough, it occurred to me that a motorised harness might offer me the liberty to
search the thermals "in my own backyard". After serious inquiries, it seemed that the Swedish
AeroSport Mosquito was the best available design on the market.
Here we are, 2O years after the invention of the infamous Soarmaster motor unit for hang gliders
("Mixmaster" for those pilots whose toes were chewed up in the prop and who experienced the
sometimes violent adverse stall characteristics of the pioneering Soarmaster design). Bolting the
engine to the wing was not the greatest solution. Then, came the Schwartz Minimum (hundreds
sold ), a rather inelegant design, which normally could not be "foot launched" in most conditions.
I needed steerable wheels on the control bar, and the motor unit was not entirely liberated from
the wing. The design Ropulcin, wa an improvement on the Minimum but still needed wheels, and
total weight added to your wing including your pod harness, was well over 35 kilograms. Not
good for soaring.
It took the genius of the Swedish Aerosports to incorporate all into a lightweight,
aerodynamically clean motor harness in the late 1980's. They have been producing the Mosquito
since 1989, and have succeeded in bringing truly easy foot launch capability with this harness that
folds up into a slightly oversized pod harness bag, all for less than 23 kilograms.
The original Mosquito used a Radne-Raket 100cc two-stroke engine, which developed 10 hp at
8800 RPM. Fan cooled, clutch equipped, with decompressor for easy pull starts. Using a 4:1
cog belt reduction and highly efficient Kevlar/Carbon/ Fibreglass propeller of 135 cm diameter,
this original configuration produced 38 kg of static thrust. The largest pilot to fly with this system
is 1.98 meters tall and weighs I10 kg. naked. In the promotion video available from AeroSports,
a 75 kg. pilot takes off with a very light headwind in (count them!) less than 10 steps, with the
original l00cc engine, and climbs out at better than 1 m/sec.
Since 1996, the Mosquito is equipped with the Radne-Raket 120cc engine. l5hp at 8800 RPM,
with a 3.5/1 reduction, and using the same propeller, produces 46 kg of static thrust. This is the
unit I have, and (at nearly 80 kg naked weight) I have no problem climbing out to 700m AGL in
about 10 minutes on any calm morning, or to 1500m AGL in 20-25 minutes from launch.
I have tested it on a number of gliders, including the Twist 17, Ellipse, Funfex, Topfex
Finsterwalder, and my favourite Sensor 610E. What's great is it can be attached to any hang
glider by the regular hangstrap. 23 kilograms is, after all, only about 13 kg more weight than your
current standard pod harness for free flying. You can see that the glider does not suffer from too
much added wing loading.
The sink rate of my Sensor remains practically the same, whether soaring with my ordinary hang
gliding harness or with the Mosquito, engine at rest, landing gear retracted, propeller blocked.
What is just as interesting is that flying the glider (stability in turns, ease of handling, the wonderful
sensation of free flight) is not at all compromised by the addition of the Mosquito.
lf you think a propeller shaft sticking out the behind of your harness looks bizarre, think again.
The lightweight motor is supported on the ground by the two retractable landing gear tubes,
making for no extra weight for the pilot to carry~ apart from the 4 litre gas tank attached to the
top of the control bar frame. Easily manoeuvred on the ground into takeoff position with the pilot
buckled into the harness and ready to pull start the unit by' himself. The motor weight is
supported by the landing gear as its nylon skids slide over the (preferred) grass takeoff area up
to the moment of takeoff. The classic Keller/ Airstream type harness is specially built with its
hang point designed to compensate for the extra weight of the motor, for comfortable and
efficient inflight performance After all, soaring performance is what they were looking for.
Although 4 litres will give you an hour of nearly full throttle engine run, I have personally flown for
over 2 hours at a time, engine on, for the 4 litres, on a calm no lift day, just by nursing the motor
along at efficient cruise. To say nothing of the hours I spend at cloud base on those great thermal
days after climbing out and shutting off the engine. In-flight restarts: no problem! Release the
propeller brake (which keeps the prop in a safe, low-drag position; no need for a foldable prop,
really!), pull decompressor and choke, and in 2-3 pulls a cold engine starts. No need for choke
if it's still warm.
Maybe you worry about landing with the extra weight behind. Think again! A typical landing
approach, feet out of harness, engine off: the landing gear touches first, and you flare like always.
It's that simple! The landing gear actually acts like a braking system; slowing that last instant of
flight while supporting the harness weight, allowing you to make a precision ;pot landing, full
flare. You can always add control bar wheels for security, but they are not necessary.
Installing The Mosquito
There are two modifications to be made to your hang glider:
1.Cut the keel at about 120 cm. from your hang point.
2.Where the side flying wires join the leading edge, add deeper loops (cable or good cord)
to attach the side to side limiter wires of the notor harness. Obviously, we need to keep
the propeller fron, swinging too much and cutting the sail.
From harness bag unzipped to full installation ready to fly configuration takes less than 3 minutes,
not even hurrying.
Launching The Mosquito:
If you have any foot launch towing or trike foot launch towing experience all the better. After all,
the thrust line is basically the same. But even with no towing experience, we all know what its
like to run in the landing zone with our hang gliders. There comes a speed when the glider wants
to fly and lift you off. All you need is thrust. For many pilots the adding of thrust (whether in the
form of a towline in front, or a motor behind) poses a psychological barrier, a fear to overcome.
The extreme ease of launching a Mosquito equipped hang glider quickly helps the pilot overcome
this fear. Also, once airborne you are not directionally restrained by any tow rope: you are free
to turn in the first thermals you encounter. I often find lift areas right after launch and start my
climbing turns at 20 metres AGL!
Get in the harness and start the motor; let it warm up for about a minute. The centrifugal clutch is
handy: prop spins The ; only at a certain RPM. . Lift propel your glider as usual. When ready,
give it full gas with the between-the-teeth clamp type accelerator. (This throttle may seem funky,
but it works well, freeing your hands). I've rigged up a second and parrallel accellerator onto the
harness for using after getting airborne (AHORA ESTE SISTEMA VIENE DE SERIE).
Once in the air, I switch to this more precise throttle.
Run as usual, with even longer steps, until airborne. With no- wind this will be about 10 meters;
with 10-15 km headwind, about 3 meters. Resist the temntation to push out the control bar. The
bar will already be about 10cm behind where it is in free flight. Let the wing seek its own best
trim, best glide. Remember this is not a high powered trike! You've got to be sensitive to the light
climb rate.
Look for the lift! Use the light thermals once you get to a safe altitude. You can work them up
with the motor still on; best to leave it on, even at idle, until you find excellent soaring conditions.
When you zip closed the harness the landing gear retracts automatically.
Freedom
The MOSQUITO has given me the freedom to search for thermals in areas where it's impossible
or very inconvenient to tow up. Even at my traditional mountain flying sites like Laragne or
Aspres, I've had great fun taking off from the L.Z., even while other pilots are still trucking up the
long turnarounds or sitting on launch waiting for the wind to pick up. Naturally, all this invites
comparison with paramotoring. For me the advantages of the Mosquito are far more
interesting.~. I fly in conditions when a paramotor would not even be setting up and at speeds
where a paraglider would collapse. Imaeine a race to a point 10 kilometers away and 1000
meters above the landscape. Which machine would arrive first? It's obvious. One of the most
important differences I would like to emphasize: the ease the adaptation. Most paraglider pilots
have a fairly difficult and delicate time adaption to the launch phase of a paramotor. Not so with
the Mosquito. The hang glider remains rigid and flyable right up to the running speed of takeoff,
after which the pilot flies like he is used to.
What about the noise level? I asked Johan Ahling about the tests they have done for the Swedish
Aviation Authorities. "They went very well. We are quite a bit under the 68 dB(A) limit of the
weight class. I think we came up to a maximum of 57 dB(A). It is important that these
microlights are quiet in order to keep them popular in the public s eye."
I personally thank them for being a serious company, with a fine product, which has already
given me nearly a year of fun, independent flying!