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Flying in
gusty wind conditions or in hot air with noted thermal
activity can impart tremendous loads upon the airframe.
It is not uncommon to experience load factors (g-loads)
ranging from -1.5g to +3.5g or more when flying in
“bumpy” air. For some aircraft, the structure is not
capable of withstanding much more than this! And if
there is any damage from a less than ideal landing or
other undesirable operation or handling, the safety
factor can be reduced significantly.
When an
aircraft experiences a gust, the effect is an increase
(or decrease) in angle of attack that is proportional to
the ratio of gust intensity to the airspeed. And a sad
fact is that a small plane encounters the gust more
rapidly than a larger one due to obvious relative
scaling . So our model aircraft are “jolted” by this
aerodynamic impulse more than their full-scale
counterparts which cycles the structure more violently.
Another factor at play with our models is that an
aircraft with a lighter wing loading will experience a
larger vertical acceleration (g-loading) for a given
gust intensity and thus will experience more structural
stress! So, it suffices to say that our aircraft are
more vulnerable to the effects of air turbulence and
gusts, particularly when one considers the fact that
model structures are also generally less validated and
tested than the “big boys”. You couldn’t afford a model
jet that was designed/built using full-scale
certification practices!
So what
can we do about this? Well, we can’t control the
atmospheric conditions but we can control how we operate
within them. The increase in g-load due to gusts is
directly proportional to the speed at which you are
flying. So, when it’s clear that gusty winds or bumpy
air is present, just SLOW DOWN. Every percent you
decelerate from the initial speed is a percent reduction
in load factor due to a given gust intensity. This is
really the only recourse you have to protect your prize
aircraft from potential, unexpected structural failure.
It’s as simple as that! |
