January 5, 2008 16:37 - Delta Stunt Kite Carves Hot Summer Breeze
There was just enough time, we decided, to give the delta
stunt kite a fly before lunch. The day was hot, very hot by most
standards, at around 39 degrees Centigrade. That's over 100 on the old
Fahrenheit scale. There was hardly any cloud cover either, so we slapped
on some sunblock.
Down at the reserve near the school, we set up the kite out on the
grass, a fair distance from the surrounding trees. The breeze was in the
3 Bft range most of the time, as far as I could tell. We must get a
wind meter soon...
The first few launches weren't successful, with the kite
getting knocked out of the air by tree turbulence in most cases. Spins
and stalls led to fairly gentle contacts with the ground. I have to
admit to one actual crash, where the kite sped off sideways, at a height
of only a meter or 2. It took a dive, and my correction was too little,
too late. It sat there on the ground, a forlorn twisted heap of nylon
and fiberglass. Critically injured and fighting for life... well
actually, it didn't turn out so bad after all. Although most of the
fiberglass-to-plastic connections had popped apart, no damage was done.
There was a tiny hole in the sail, which might have been there before.
It was time to let out more line, and get further away from those
pesky trees and their turbulence. With about 35 meters of line out, and
better air, the kite was soon soaring up and away. With a bit of height
and ample wind, the kite proved fairly easy to control. Even so, I was
concentrating hard to avoid unexpected landings and making my poor wife
run around after the kite like before!
With a nice safe line angle of 40 degrees or so, I felt for
the edge of the wind window in both directions. In between, I cautiously
flew from side to side, trying to keep a constant distance from the
ground. Climbing the kite higher, I was delighted to see how steep it
would fly, easily more than a 60 degree angle. Just when I was doing
this, the wind gusted even stronger, keeping the lines almost straight
and exerting a decent pull on my hands. OK, so much for flying in
straight lines... let's try a loop!
Starting at about 50 degrees above the horizon, I pulled in
some right line and watched the kite circle round clockwise, diving
towards the ground. The turn radius opened up a bit, so I pulled in some
more as the kite shot around close to the ground and back up the other
side of the loop. Success! My first loop! Now for the other direction.
Much the same thing happened, except I turned too sharply at the bottom
and so the loop was more like a spiral. Anyway, practice makes
perfect... At least the kite didn't hit the ground.
This final flight was a good long one, by our standards
anyway. Nearly five minutes in the air. Hey, this is only the second
time we've been out with a stunt kite!
Now for a few notes on the flying during that last flight.
Line tension varied a lot, which was mainly due to thermal turbulence I
think. We were flying high enough and far enough from the trees to be
unaffected by their wake most of the time.
I learnt to act quickly when the kite's pull died! A few
quick steps backwards kept just enough tension to keep the kite under
control and fly it somewhere else. Sometimes quite big movements on the
control lines were required.
Whenever there was plenty of tension in the lines, I trotted
off downwind to keep some distance from the trees. This drove my wife
nuts, since she was trying to video the kite and kept losing it straight
overhead. We did end up with some reasonable footage though.
When the kite was speeding sideways, the feel was spongy but
only a few centimeters of line movement were required to steer it.
However, when way off to the left or right, much bigger movements were
required to turn the kite back to the center again. I was never game to
turn toward the ground when doing this! If misjudged, the kite would
really hit hard.
To sum up, I had a lot of fun even if May, my wife, didn't.
As my skills improve though, she will be doing more photography, which
she enjoys, and less retrieving, which is no fun at all. It was nice to
keep the kite in the air for a few minutes, which gave opportunities to
plan what to try next. Maybe we'll try flying at a beach next time, and
attempt some figure eights and triangles! Forget deliberate stalls for
now, this kite stalls on me often enough already, and I don't want to
encourage it! ;-)
January 7, 2008 15:49 - New Rok Kite Floats Up And Glides Down
Gee, this Rok kite saga just continues. We are now onto MBK
Skewer Rok number 3, in our quest to make it fly well and be reasonably
easy to make. The bowed cross spar tensioning has caused numerous
problems during construction. It's just very awkward for the Rok design
on this small scale. Fiddly beyond belief. This time, I experimented
with a dihedral design, rather than a curved bow.
With Aren in his pram, the 2 of us headed off to the Old
Reynella reserve. The weather was warm, with a gusty breeze. Soon the
little Rok was up, and it looked promising. Stability was a bit marginal
though, so I went out to it and bent, yes bent, a little more dihedral
angle into the rear cross spar. Up it went again, and I was able to let
out quite a bit of flying line this time.
Still a few problems in the fresh gusts that came through, so
I slipped that fancy Prussik knot up a bit to decrease the kite's angle
of attack and tried again. A bit better perhaps, but the kite had a
tendency to nose down in lulls and fly around like a model glider. It
managed to get upwind of me at one point!
In stronger gusts the Rok kite would sometimes enter a long
dive to the ground, with a 50-50 chance of recovering and flying back
By this stage, I noticed that the top cross spar had a lot of
dihedral angle. On checking it, I found the joint had weakened, so it
was time to go home and see about reinforcing it. But this design should
work well. My feeling is that with enough dihedral on both top and
bottom spars, plus a properly adjusted bridle, this kite should do just
fine in moderate breezes. Like its bigger 2 meter cousins, it might also
cope well with strong wind with a tail attached.
January 8, 2008 21:29 - Rok Kite Flies High At Last
We just needed a photo of the Rok being launched, for the How
To Make A Rok Kite page on the website. The tops of the trees were
moving around, so it seemed like perfect conditions for this little
Down at the Old Reynella reserve, we soon had the kite up without
any tail. A few short flights later, it was clear that in smooth air of
just the right strength, the Rok would indeed fly well without a tail.
It would soar up straight from time to time, but then give in to rough
air or gusts which were a bit strong for it. In lighter air that wasn't
quite enough to raise it above shoulder level, it would hover quite
With a meter of tail, the kite had much longer and higher
flights. However, it still needed a bit more, so I added another meter
of looped plastic tail. Then, it soared eagerly above the treetops, and I
was able to let about 40 meters of line out.
This won't be a long post, so I'll close with a few comments about this Rok kite.
Although Roks are meant to fly without tails, this relies a
lot on accuracy of the sail surface and the bridle lines. Both of these
are hard to achieve in a very small kite!
The Rok kept flying off to the right, before I noticed one of
the knots in the bridle wasn't dead-center. I moved it maybe a
millimeter, and the kite flew much better!
The cross spar reinforcements have added a bit of glue
weight, so there goes the light-wind performance of the kite. Oh well,
it will still be a fun medium-wind kite with its tail...
This Rok flies similarly to a delta in some ways. For
example, it can reach very high line angles, and is prone to float and
fly around like a paper plane during lulls in the wind.
Unlike a delta, this kite seems to have a fair amount of pull for its size.
That'll do for today!
January 17, 2008 10:20 - Delta Stunt Kite In A Spar-Bending Breeze
Yes, it was windy out at the reserve near the Old Reynella
school. Quite cool too, so we didn't stay too long. By Adelaide
standards there was a bit of chill factor to contend with.
The delta stunt kite leapt eagerly into the air and was soon
high up in the strong breeze. It wasn't super-gusty, but still there
were times when the kite would lose speed very suddenly. At these times,
a few backward steps were necessary to keep control. There was some
wind gradient too, where the wind was much slower near the ground.
However, it was fun getting the feel of the kite in stronger wind than
it had flown in for the other 2 times we have been out. Climbing
straight up with the full force of the wind, I could see the leading
edge spars bending quite a bit!
This time I managed to get a bit more adventurous, and tried
some straight-line climbs and dives. Diagonal and vertical. They'll get
straighter with practice... Plus a few loops, in both directions. Again,
getting them nice and round is going to take some extra practice! A big
wobbly figure eight as well. I guess this stuff will be a bit easier
down at the beach with a smooth breeze off the ocean, and fewer gusts.
I was surprised that the kite didn't have a heavier pull,
considering the strength of the wind. A small parafoil stunter might be a
different story! We might get one later on.
A couple of unexpected landings resulted from sudden wind
drops while the kite was low. I did my best to make them soft, by
throwing both hands towards the kite when it looked like crashing, to
keep its speed down. One time, my loss of control near the ground
resulted in some tight looping and spinning before I managed to get some
airspeed into the kite while it was pointing away from the ground. This
little display, plus the recovery, impressed my wife no end. She
thought it was deliberate!
Anyway, this short flying session left me hankering for more.
However, we might head down to Brighton beach next time! This inland
stunt kite flying is a bit dodgy...
January 19, 2008 21:37 - Delta Kite 4 - Promising Light Wind Floater
With the end of the month approaching, it was time to test
fly the latest kite in the MBK Skewer series. Finally, I have returned
to one of the first types of kite I ever made out of bamboo skewers and
plastic, the Delta. However, this time I incorporated a couple of
standard features that were missing from my first 3 versions. Firstly,
floating leading edge spars. Floating since they are not attached
rigidly to the nose of the kite. Secondly, a keel to aid directional
stability. Also, since the bamboo spars are not flexible enough for a
really genuine delta kite of this size, some bow is held into the cross
spar with a draw string.
Out at the Old Reynella reserve, the wind was fresh and
moderately gusty. Most likely a bit too fresh for the Delta. I was
right, it turned out, but the little kite still managed to strut its
stuff in the lulls. I knew it was a touch nose heavy, but still wanted
to see how it would fly.
Initially, it showed signs of gliding around instead of
settling back on its tail to catch the wind. Yep, too nose heavy
alright. To fix this, I attached a paper clip to the tail end. This did
improve its flying, so I will replace the paper clip with strips of tape
Stability was a bit marginal so I added another meter of
tail. The keel seemed to be about in the right spot. Perhaps it could go
back a tiny bit in light winds. The amount of bow in the cross spar
would probably be enough in steady light winds, but it wasn't quite
enough in the fresh breeze.
Although the kite kept diving to the ground, I had fun doing
recoveries by suddenly letting all tension out of the line. The kite
would just settle on its belly, drifting down, before recovering
straight into a vertical climb. If it was off to one side, it would also
drift or fly back to the middle of the wind window.
Also fun was getting it to hover down low, with so little
tension in the line that for some moments the kite was actually tethered
by the line at my end just sitting in the grass! No tension at all in
the reel. Then, with a little tension applied to the line, the kite
would slowly accelerate straight up and find faster air.
A couple sitting on a bench nearby seemed mesmerized by the
antics of the Delta. Perhaps it will inspire them to make or buy a
At one stage, the little Delta kite got snagged on a tree
when it flew way off to the side. I made the wrong snap decision. By
releasing all tension in the line, the kite would have recovered for
just long enough for me to run to one side and fly it away from the
tree. Instead, I tried to pull in line to get the kite in front of the
tree, whereupon it dived into the leaves on the down-wind side of the
tree! I managed to pull the kite away, with the line still threaded
through the tree. Eventually, the kite managed to free itself by flying
the line out of the top of the tree. Whew!
After some more flying, it was time to walk home. My wife May
and little boy Aren met me halfway, wondering where the heck I had
gone! Dadda! screeched Aren at the top of his lungs, while I was still
100 meters away...
January 24, 2008 22:17 - Delta Kite 5 Bravely Soars Higher In Blustery Breeze
Another Delta already! Yes, I knocked this one together I
mean very carefully constructed the MBK Skewer Delta in order to take
all the pics for its How To... website page. Delta Number 4 proved the
concept. The only real difference is that the cross spar on delta number
5 is slightly closer to the nose than on number 4. I think this is the
most satisfying skewer kite to build in the series so far. It takes some
time to do it accurately, but the reward is a high performance kite.
For its size and humble materials anyway! Now, on with the test flight
Earlier in the afternoon, the wind seemed quite light with
just a little movement in the trees. Great I thought, perfect for the
delta! However by the time we arrived at the Old Reynella reserve, the
wind had picked up considerably with gusts of really fresh wind moving
through. Still, it should be possible to see if the delta is in good
trim. Several loops of tail plastic were tucked away in my pocket, just
in case a bit of extra drag was required on one side of the kite. May,
my wife, had brought the camera since we needed a flying shot of the
kite for the bottom of the How To... page.
MBK Skewer Delta kite The first few launches were ok, but the
little delta was still a touch nose-heavy and tended to glide right
back to my feet in every lull! Also, like delta number 4, it pulled
right every time with too much wind under its sail. So, I added a few
extra strips of tape to the tail to correct the balance. Also, I taped
just a single loop of tail plastic to the right wingtip, to correct the
turning tendency. On the next flight, no more gliding upwind, but it
pulled left quite violently! How sensitive is this kite?! To cut a long
story short, the wingtip tail ended up being just a centimeter or 2 long
to properly correct the turning problem! Quite surprising. With a short
main tail, this is a finely balanced little aircraft.
Then followed a few longer flights where I let out 20 or 30
meters of line. Unfortunately, the delta couldn't cope with the wind
strength and soon ended up on the ground again after being forced into a
dive. However, the dive was not always in one direction, so that
confirmed it was in good trim. We are really looking forward to a light
wind day now, to see the little MBK Delta strut its stuff!
January 28, 2008 22:29 - MBK Delta Kite Hovers and Soars In Light Gusts
On the way back from Aren's grandparents' place we stopped at
the Holden Hill reserve off NE Road. We were prepared with 3 kites in
bags, all with their own flying lines. With a fairly light breeze
outside, we took out the MBK Delta and the MBK Kids Diamond. The little
barn door kite would have had a hard time getting airborne!
The delta went up first, with the wind gusting right up close
to its limit. At last I was able to give this kite a really good fly
inside its wind range. It was fun hovering near the ground and climbing
to max height, depending on the wind strength. Sometimes hauling in,
sometimes letting line slip out with the kite climbing during long
Although the breeze was light and variable, the kite actually
got into trouble quite often during lulls. It was prone to long rolling
dives if the nose happened to dip too far during a lull, or perhaps
straight after being upset by some turbulence.
The kite would begin gliding slowly upwind, then down would
go the nose until the kite was diving straight at the ground and rolling
left at the same time. Usually, it would recover just before contacting
the ground. A couple of times I released all the line tension to force
it to recover quicker. Letting the bowed cross spar do its stuff,
righting the kite as it drifted straight down. To fix the diving, it
should just be a matter of adding yet more weight to the tail end. A few
more strips of tape on the trailing edge.
This kite should really be flying on 3kg nylon, since the 20
pound Dacron is definitely too heavy for it in its comfortable wind
We also flew the MBK Kids Diamond for a while. Aren flew it
briefly, but kept running downwind towards it! Whereupon the kite
promptly settled down on the grass of course...
The diamond could be reliably looped to the left by pulling
hard on the line. After my experience several days ago with trimming the
delta to fly straight, I knew what to do when we got home.
All it needs is a small bit of tape sticking out from one
wing tip to produce a bit of extra drag when the airflow past the kite
speeds up. With just the right amount of tape, it should balance things
out nicely, and enable the little diamond to fly in much stronger wind
than it does now. A more efficient fix than just bunging on another
meter of tail!