Today I was out in a big wind!
So the big Atlantic weather is with us now and I have just retreated from a shoot of a windmill on a hill I have been after for months, the HQ2.0 fairly ripped the arms off me and, although I’d quickly realised I had too much kite before the wind, it was an epic struggle to get it back without snaring overhead wires (telephone, imagine the shame in trying to get British Telecom to co-operate in a kite or line recovery!), swirling trees, lampposts, hedges and rooftops. It was a case of hold on until the gusts eased and then haul away whilst dancing with the kite to keep it in an uncluttered piece of sky! Back at base I ponder the kite I should have used: Paul’sFishing Kites (PFK) Nighthawk.
Although it’s a joy to fly I have never got on with it as a camera sky-hook because the wind-speeds it works in are characterised by sickening turbulence making photography almost impossible as the rig swings about like a floundering ship on a stormy sea.So it looks like Bft 6 is ‘too windy for KAP’.
On the packet it says the PFK Nighthawk will fly in up to 40knots, that’s the kind of weather I like to keep out of, if true this kite could push the KAP envelope into Bft7 or even 8!
Today I was out at between 10 and 11 so I was dealing with a rising wind of 25 mph gusting to 30. The violence of the gusts was such that the kite would heel over and then begin to spin forcing me to run down wind to prevent a powerdive into all manner of obstructions. It’s difficult to describe how stressful this situation can be. The pull on the line in these conditions is severe, tying the line off was not an option as the obvious anchor points I could see would place the madly veering kite in the way of wires, the mill itself or houses whose roofs looked ever more fragile compared to the hammerforce of the diving kite!
The 2 flowforms I have match the chart for the parafoil 7.5 pretty closely although the HQ 2.0 at 26mph is really on its beam ends!
The tough little delta flies well in most brisk breezes but can’t lift a rig until it’s biting into something like Bft5 or better. It has 2 alarming chacteristics: one is the racket it makes and the other is its tendancy to overfly the flyer. The noise turns out to be a good indicator of its lifting capacity, if the noise stops so has the lift. The steep flying angle means it’s a kite that demands the attention of the flyer once the rig is committed to it’s care; it’s a very mobile kite which constantly reacts to changes in wind strength by tracking to left or right. The small surface area means that once the required lift is lost, even if only by a fraction, the rig drops really fast!
This is what I get when I fly my rig from the PFK:
My rig swings about madly as the line is jerked about by the kite! The hit rate for sharp images in these conditions is practically zero! I think it’s fair to say (certainly for these parts anyway) that the bigger the wind the bigger the variation in wind speed.
So what I’m after is a kite that is tough enough to take the battering of a big wind but also stable enough to bridge the lift gaps big winds tend to have. It’s certainly not simply a matter of a bigger kite as the multiplied forces would get painful pretty quickly. My thoughts on dealing with the big range of forces in acting on a single kite (trains of kites is another matter!) tend towards 5 ideas:
1. Elastic Bridle. The idea was desrcibed at KAPiNed10 by Bernard-Noël Chagny of an eleastic bridle to soften the effect of changes in wind pressure on a rokkaku sail to reduce the stress on the spars: the idea being I could fly a slightly bigger PFK and have the eleastic spare the extra stress on the kite and the increased sail area save the falling rig.
2. A ‘reefable’ kite. Sailors tell me reefing is the way to go. When faced with too much sail before the wind sailors’ reef’ in the sail area to reduce the risk of having the boat blow over. Many kites are adjustable but my favorite is the Brogden prize winner from 1908 for no other reason than I think it’s a very pretty kite in the sky. I have a half size one in aluminium and ripstop and it’s something of a performance to tune it to the wind and it has a nastly short line ground loop characteristic. The 5 sails mimic the sails of a square rigger ship, in theory I can vary the tension on each sail in much the same way as reefing. In practice this kite is a bit of a handful and can take an age to get dressed for the wind and even then its very easy to get it out of balance as it has so many adjustments!
In the picture is Charles Brogden with the nervous look typical of a kite flyer who is expected to ‘perform’ in public; only he knows the true extent of the risk in what he is about to do! This photo is so evocative of the ‘dawn of flight’ era, at the time kite builders and flyers above all others were making the dream of flight real, kite designs were leading edge technologies in a world still largely powered by steam and horse. Nothing would come close to this golden age of kiting until Dominina Jalbert created the parafoil and opened up a whole new world of wind powered sports on land and water 50 years later.
3. A smaller ‘softer’ flowform. Reducing the area from 2m2 to something less with a bigger wind spill might work. Simply reducing the size alone would not be enough as these kites have a sort of ‘paper bag’ flight dynamic when they are overblown.
4. Drogue the life out of the kite. It’s possible the PFK can be damped to a degree by a carefully towed drogue. I have seen this work well on the flowform kites, my hope would be that the drogue slows down the tracking of the kite and thus reduce the movement of the line.
5. Gyro stabilisation of the rig in the roll and tilt axis. A ‘roll rig’ is very effective at cancelling rig movements in ‘reasonable’ winds at the cost of a slight increase in weight. Having seen some of the movements ( including 360s around the flying line!) I’m not sure a roll rig could keep up but its worth a try!
So with these ideas in mind I’ll probably start with the drogue, then borrow a roll rig and see what happens next time the wind gets fierce.
Now of course the wind has dropped to nothing and all thoughts of fighting with it are gone:
The full size shots are at: