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Former world champion paramotor pilot Michel Carnet shared some
insights on reflex wings and speed that I thought was very well put and
spot on. I've included it here, with permission.
Since 2003 when the original Action came out, we have been spoilt
with fast bulletproof stable reflex profiles, in wings such as the
ReAction, Synthesis and the Nucleon.
Some of the performance gain of the Hadron is due to a reduction of
Reflex in the profile. The dilemma for manufacturers is to get more
efficiency without compromising stability. I, for one, would not wish to
see paramotoring competition go the way paragliding comps have gone,
with lots of deflations and emergency parachute deployments.
At the moment, there are three ways to make a wing go fast:
- Big reflex wing, that needs full speed bar to achieve top speed,
hence lots of reflex.
- Smaller reflex wing, that flies naturally fast on fast trims or
part speed bar, therefore with less reflex.
- Small classic paraglider, no reflex and relying purely on high
wing loading. The smaller wings tend to be nippier and naturally
fast, so they are currently in fashion in slalom events. However, it
is possible to make big reflex wings turn very fast in slaloms,
although most of the mods used by factory pilots have not found
their way into production models, as yet.
However, it is possible to make big reflex wings turn very fast in
slaloms, although most of the mods used by factory pilots have not found
their way into production models, as yet.
One advantage of higher wing loading is that for a given high speed,
the L/D ratio (Lift over Drag) can be significantly better than on the
same model with lower wing loading. So the extra power required to fly
level on a smaller wing can be balanced with the better L/D ratio.
This effect can be seen in paragliding when ballasting has a very
small effect on max speed but a significant effect on glide angle when
gliding into a headwind.
It was very interesting to watch the Hadron compete against the
Nucleon in some of the various Opens in 2011. In the Cloverleaf slaloms
in the French and British Opens, Pascal Vallée and David Muzellec were
the best pilots with similar amazing fast times on their respective
Hadron 22 and Nucleon 31.
The same thing happened in the Figure of Eight slalom that eventually
got cancelled in the Belgian Open.
When it came to thermalling tasks in the French and Czech Opens, the
bigger surface area of the Nucleon 31s made all the difference, showing
the advantage in speed range of a large reflex wing that can be
accelerated.
But with the influx of slalom only events in recent years such as the
World Air Games, Parabatics, Slalomania, Icarobatics and FlyGames, some
competition pilots have been forced to select more extreme equipment
that favours slalom flying, with emphasis on high wing loading and
powerful engines, with little consideration on reliability, economy,
noise,
directional stability etc.
This is a significant departure from the all round equipment you need
for traditional competitions such as the British Open or the World
Championships, and even more from what most recreation pilots need in a
wing.
Another reason for choosing high wing loading in some slalom
competitions is that you may need your legs for grabbing gym balls,
kicking small balls, catching hoops or even launching whilst the clock
is ticking, thus making the use of speed bar difficult.
There is an old proverb that says: Pain is proportional to the square
of the velocity of the crash! (ed: this is the law, too)
So flying low, fast and furious is great but it is important not to
crash, or at least to be able to slow down a lot before a crash impact.
Michel Carnet
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Michel Carnet nails the stick on full speedbar.
This article highlights the tradeoffs between
standard and reflex gliders, and between larger and smaller reflex
gliders.
Another consideration for reflex wings is that they
become more susceptible to collapse when flown on full speedbar if the
brakes are pulled--a condition they are not intended to be flown in. But
competition tends to push it. There are ways to minimize the risk,
including with control design, but those are not necessarily employed on
production gliders offered to the public.
Pylon competitions all but require reflex speed but
extreme care must be exercised! |
