This type of question comes
up often and there are a number of points to consider which will influence
a decision or choice.
A stack of Flexifoil power
kites can be tailored to the conditions (wind). Both the NUMBER and SIZE
of kites can be adjusted. For example I regularly use up to four 6 foot
stackers together in winds from about 15mph upwards. If the wind gets too
strong I land and take one or two off !! A very useful combination is TWO
10 foot Super 10s. Generally the 10 foot is supposed to have up to four
times the pull of a 6 foot but in practice I would suggest that four 6
foot Stackers pull slightly stronger.
This raises an immediate question of 6 v 10 foot kites !! On its own or in a pair the stacker is faster than a 10 foot and needs less arm movement to turn. However when there are three or more Stackers, the overall stack becomes less maneuverable and you must pay attention to the stacking lines which need to be good quality and the SAME length. Generally use fairly short stacking lines – I’ve tried them as short as 2 feet between kites. A big stack does tend to move around in the air and at times the oscillation can become quite violent. You must make sure that none of the kites has sand trapped inside since it upsets the characteristics significantly. Therefore if you use two Super 10s the tendency to oscillate decreases but you do not get the adjustability of a number of 6 foot stackers !
On the buggy the “stack” has to be “worked” to keep the kites moving since they will pull harder (ie: use a sine wave type of flying). This means a lot more arm movement and hence effort. (I recommend the use of Peter Lynn Safety handles rather than padded wrist straps). If the stack is pulling hard you can allow the stack to rest in a more or less fixed position in the sky as you buggy, however if you then try to more the kites the increased pull is far too much, therefore there is a genuine compromise between the “static” power and the need to put a lot of effort in !
Using standard Flexifoils the
up wind performance is fairly poor. The Prospeed 6+ is better in this respect.
The reasons are quite complicated and it is best to refer to papers written
by Peter Lynn, however in a nutshell
Peter suggests that an ideal “traction kite” should have a low MMR – ie:
the maximum pull of the kite in motion should be close to the minimum pull
of the kite which is either directly overhead or at the edge of the wind.
The standard Flexifoils (and the standard spars) do not really have ideal
MMR characteristics, however the Prospeed and its intermediate spar try
to compensate for this somewhat).
One big problem with a stack
is the difficulty of launching and landing (see my other faqs). This is
a major concern if you crash miles up the beach when it is unlikely that
you can get immediate assistance and if sand blows into the kites its almost
packing up time !! (Try it and see !!!)
Hence in conclusion the Stack:
· Needs a fair amount
of effort to fly
· Needs handles rather
than straps which will reduce fatigue
· Has reasonably poor
upwind performance
· Is difficult to launch
and land single-handed
· Can cost a lot for
several kites and stacking lines
However:
· It can be tailored
for the conditions to get an ideal power / pull
· Its particularly
good in high winds
· Looks very impressive
in the air
· Excellent for a good
“workout” !
A 4 line kite overcomes many of these apparent “problems”. The additional degree of control afforded by the brake lines means that the kite can be launched and landed at will which is a major advantage and generally it will fly much better upwind and will be faster in the same conditions with LESS physical effort.
However the disadvantage with a 4 line kite is its FIXED size which places a practical limit on the range of winds it can be flown in. I discuss this in other faqs, but for example a 3sqm kite needs about 15-18mph+ for buggying with a realistic upper limit of around 26-30mph for the average flier. A bigger kite eg: 5sqm needs about 8-12mph up to 18-20mph. Therefore there is NO ideal 4 line kite. The wind range can be extended using shorter lines in higher winds and longer lines in lighter winds however changing line sets can be inconvenient and without great care you will get knots and tangles. I suggest that a 3.3 Blade is better when average winds are stronger , but a 4.9 Blade when average conditions are milder - a difficult choice since you really need BOTH to get the full benefits. Therefore in conclusion the 4 line kite:
· Is faster and more
efficient
· Is very much better
upwind
· Is easy to launch
and land
But:
· Costs more initially
than one or two "standard" Flexifoils
· Has a “restricted”
wind range