MBK 1-Skewer Sled
Well, up went the little sled with the first thermal to pass through the reserve.
Darn thing had a bad tendency to hang right, so it needs adjustment.
Never mind, trimming kites to make them fly better is part of the fun!
With the photo shoot over, thanks to my wife May with her digital
camera, I let out some more line and flew the sled up around 10 meters
or so for a while...
Partly due to it's flying fault, the little sled collapsed a few
times and eventually managed to lose a tail! The paper clip must have
been jiggled like a tea bag at some point, and somehow the tail
attachment loop found its way around the bend and slipped off. First
time that has ever happened.
Funnily enough, with the right tail gone,
the sled flew much better! See how 2 wrongs can sometimes make a right,
in kite making!
Stay tuned for how I fix the kite, and for descriptions of some much more successful flights!
Date: Fri 17 Aug 2007
Location: Old Reynella (vacant block)
Weather: Light to moderate breeze, variable
Kite(s): MBK Skewer Sled prototype 1
Comments: It was getting a bit late, but there was some breeze
so I decided to quickly repair the sled kite and head off. Went past
the reserve, but it looked risky with kids playing and kicking a
football, so headed back up the hill to the vacant block. Pretty soon I
had the kite out and hooked onto the fishing line. No problems launching
with the fresh breeze. A bit too fresh, as I discovered a tendency for
the kite to hang left. Sure enough, each gust would send it looping left
and losing height.
After bringing the kite in, I tied a couple of extra knots
into the right hand bridle line, with the free end of cotton from the
knot. This little trick shortens the line just a fraction. Sure enough,
the kite took off straight as a die on the next launch. Actually, there
was still a small tendency to hang left with the stronger gusts, but it
was very much better than before. With the take-off time noted, this was
a real chance to break our duration record!
Soon, 50 meters of line was out. I had to stand in just
the right spot to avoid any danger of a tree landing. This vacant block
is quite a small spot to fly a kite! A few people walked past and didn't
seem to notice the kite. The light nylon line must be nearly invisible
from a distance. Not to mention the kite itself if you happen to be
right under it!
Gentle thermal activity was still around, as I discovered
when the little sled soared up to a 55 or 60 degree angle from the
horizontal. It can't make that angle in a steady breeze. Earlier in the
day, 5 pelicans in a V-formation soared over our house and then on into
the distance, without a lot of flapping! Great soaring birds they are.
A lightweight swivel would be handy to have on the line.
The monofilament line is always very twisted from being wound onto the
reel, and this has the effect of twisting up the sled's bridle lines in
flight. This effectively shortens the bridle, so the side flaps tend to
collapse inwards occasionally! Only a minor problem.
I saw a bird flying quickly toward us at about 10 meters
up. It only spotted the line when about 5 meters away from it, hastily
changing course to avoid a collision!
With the sun setting, the freezer bag plastic actually
started to glisten. Particularly the tails, as they made a silvery
glittery dance in the dying evening breeze. Ahem, excuse me while I wax
More down to earth, I put Aren's socks on for the 6th
time, as he insisted on pulling them off in the cold evening air! Also,
my duration attempt was in danger of being cut short as I struggled to
keep the little fellow entertained while the kite moved around in the
wind shifts and gusts.
Towards the end of the flight, the breeze smoothed out,
then finally died altogether. Winding the line onto the reel as quickly
as I could, the kite touched down while still about 10 or 15 meters out.
A new duration record of 38 minutes!
Date: Wed 15 Aug 2007
Location: Old Reynella (reserve)
Weather: Moderate to fresh breeze, variable
Kite(s): MBK Skewer Delta prototype 2, Modified Baby Sled
Comments: Plenty of wind about, so Aren and I went down to the
reserve with 2 kites under the pram. Hoping to break either the
altitude record or the duration record or maybe both today!
First up was the delta, this time with a bit more bow held
into the cross spar. Actually, kite geeks might correct me on that and
call it a 'spreader' rather than a cross spar. Anyway, in the ample
breeze, the delta was soon laying out line into the sky. Being a bit
tricky in gusty wind, it ended up on the ground a few times. Nearly
every time, I managed to relaunch without walking out to it, as
described in an earlier log entry.
Finally, it was nice and high and I let the reel spin out
to just past the 50 meter mark, let's say 51 meters. As I hoped, it got
up to a very high angle once or twice. With the help of some thermal
activity I'm pretty sure. That was the altitude record broken, simply
due to the very high line angle which I estimated to be about 70
degrees. With not much sag in the line at all I might add. Let's see...
calculate, calculate ... that means the kite was about 48 meters off the
ground, not even allowing for any line stretch!
When the wind got a bit strong from time to time, I
discovered another of its characteristics. It would start to loop very
tightly, with its 4 meter tail forming a 3 or 4 loop corkscrew shape.
Seems like when it got like this, the tail wasn't doing its job very
well. The fix was to walk quickly toward the kite to de-power it
completely. Then it would recover and race away in one direction or
another, before eventually climbing high again. Maybe using 2 or 3
shorter tails instead of one long one will fix this looping problem?
Definitely something to try later! It's easy to change tails on MBK
After the fun of breaking the altitude record it was time
to try the Baby Sled. Maybe the duration record would fall now, with the
decent breeze up there filling the more stable sled kite. I haven't
flown this for a while. Surprisingly, this little shop-bought kite felt
like a bit of a dog after flying the delta! It took much more breeze to
get up there, and being a sled tended to hang around the 30 to 40 degree
mark in terms of line angle. It came close to breaking the duration
record, but Aren was a very naughty boy and pulled out my yellow kite
bag and let it go in the breeze. Just at the very moment I was trying to
keep the sled in the air during a lull in the breeze! I ran forward and
grabbed the bag, but that's all it took for the sled to hit the deck
from about 5 meters up, unfortunately. Oh well, there's always another
Date: Wed 8 Aug 2007
Location: Old Reynella (vacant block)
Weather: Strong breeze, gusty
Kite(s): MBK Skewer Delta prototype 2
Comments: Blustery weather today, about 50% cloud cover, some
of it a bit dark so wondered about safety. Eventually decided to go out,
as bluer skies were on the way from the north east. Popped the delta in
the pram and headed off to the reserve. Too many kids of a dangerous,
kiting-interfering age were there, so continued on to the vacant block.
:-) Nothing against kids, but today I was doing some testing.
This time, the delta had some dihedral held into the cross
spar with some cotton line tied across it. Let me explain dihedral.
Looking at the kite's nose from the front, the sail is now gently bowed
upwards instead of being perfectly flat from wing tip to wing tip. Some
kites are built like this so they don't need a tail. In this case, I
just wanted to cure the dreaded instability problems! Well, it worked
The kite quickly climbed up to a steep angle on the line.
Soon, the turbulent breeze had the kite right across to the left, from
where it usually doesn't recover. But this time, it hung there for a
moment then gradually righted itself and shot back across the wind
window. And up to the top, then across to the right. Slow recovery
again. And again and again. At last, a stable skewer delta handling a
strong gusty breeze! Turbulence from the surrounding trees hit the kite
repeatedly, sometimes making it feel like I had a large fish taking
bites on the end of the line!
Having said all that, the wind was so rough that the delta
still ended up on the ground many times. But its flying characteristics
were so much better than before. What seemed to happen to this delta
and also the number 3 is that a sudden drop in wind strength causes a
stall. The pointy wing tips tend to stall before the rest of the sail,
so the kite drops a wing tip, rolls onto its back and then glides
steeply to the ground. But now, with the dihedral, I could often slacken
off the line, allowing the kite to glide free and right itself. It
would then catch the breeze and take off again, up or across the wind
Would you believe, this little single-line delta is
relaunchable! Yes, you just carefully pull it towards you while it's on
the ground. The pointy tip catches in the grass and the kite pivots up
on one spar. With care, you can keep pulling until it flops down again,
with the bridle on the bottom. Further careful pulling will line the
nose up into wind. Now, it's just a firm tug and the nose comes up and
catches the breeze. This worked so many times, far more often than I had
to walk out to get the kite. So cool. A single-line trick kite! I'm not
sure that Aren, watching from his pram, appreciated the fun I was
The kite was now flying 2 or 3 minutes at a time on the 17
meter cotton test line, sometimes reaching a 70 degree angle in the
fresh breeze. What will it do on 100 meters of fishing line? Watch this
Date: Wed 1 Aug 2007
Location: Woodcroft (reserve near golf course)
Weather: Moderate/strong breeze, gusty
Kite(s): MBK Skewer Delta prototype 2, Skewer Sled prototype 1
Comments: A sunny and windy day, with some high and mid level
cloud cover. Time to try a new flying location we found the other day.
Into the car went 3 bags, each containing a kite attached to an
appropriate tail for the conditions.
First up was the delta, which I had modified a little by
trimming its trailing edge so it goes virtually straight across from
wing tip to wing tip. A true delta shape now, whereas before it looked
more like a diamond from a distance. This left the center spar
protruding out from the trailing edge. With a fairly strong breeze now, I
went with another approach regarding its balance. With all the
paperclips removed from its tail, I made sure the bridle attachment
point was still well ahead of the balance point. As it should be for all
flat kites. Also, it now had a new 2.5 meter blue plastic tail
Even when out of the wind shadow of any trees, the air was
very gusty. The kite alternated between hanging in the air with a slack
line, and rocketing straight up to a high angle with plenty of tension
in the line. The old instability problems were still there whenever it
got too far to one side however. The continuing saga of the misbehaving
flat delta! I still have a trick up my sleeve though. We'll try it next
time with a slight bow held into the cross-spar by tying a length of
cotton line across it. Like a bow kite, but just a tiny bit of bow. It
could yet end up a great little high-wind kite. Rigid, light and stable.
Didn't want to waste any more time, so I walked back to
the car and got out the sled. Brave move. Will it survive this breeze?
Will it survive the dogs that keep walking across this field with their
owners? After untangling the twin tails and letting it fly, the little
sled soared up several meters. Walking backwards to keep some distance
from the downwind trees, I let out more line. To cut a long story short,
it had several flights, some of them quite high. All flights were
terminated by the looping caused by too much air pressure. Always to the
left. Added a paper clip to the right spar, for weight. No difference.
Mmm. Aha, maybe I could adjust the bridle.
After a bit of experimenting I discovered small
adjustments can be made simply by tying more knots into the existing
knot which tied the bridle line to the kite sail. Each time the loose
end of the knot was knotted again, the bridle line would shorten just a
tiny bit. In fact, I overdid it and on its next flight the kite started
looping to the right instead of the left when overpowered by the wind.
Ok, so lets shorten the other bridle line as well. As I was getting this
adjustment just right, the poor little sled shed one of its bridle
lines. Yep, in-flight structural failure. Tested to destruction, as they
say in the industry. Amazingly, the fluttering, broken kite continued
to fly a meter off the ground for some time!
We didn't bother with flying the diamond today, after all.
When we got home I discovered it was the sticky tape
attachment point that had failed on the sled. It had simply split where I
had cut a nick into it to stop the bridle line knot from slipping off.
Might have to tie it without a nick after all. If the knot is tight
enough it shouldn't slip off. We'll see!