what's new ?
release 2.1.3 :
- bug correction under WXP : text boxes were sometimes black...
- final release of Fredrik's Buzzard profiles (Buz One and Buz Vnose)
release 2.1.2 :
- stupid bug correction on thickness percentage computation (thanks again 
Fredrik :-)
- added "narrow" and "wide" version automatic recognition while importing a 
profile
- default profile is now the wide version of Fredrik's "Buzzard"
- both wide and narrow profiles of "Buzzard" are added to the package

release 2.1.1 :
- added Angle of Attack computation (relative to center pannel and A 
bridles)
- added center panel thickness percentage computation
- change slightly the buzzard profile

release 2.1.0 :
- number of B lines as a parameter
- B_B spacing between C lines as a parameter
- last imported or exported file appears now in the title bar (thanks 
Fredrik)
- A scaling didn't affect C_C value --> now fixed
- export now working with decimal separator set to ","
- default profile is now a flying one --> I have choosen Fredrik's Buzzard 
profile :-)

release 2.0.9 : beta version

release 2.0.8 :
- bug correction : C_C spacing was limited to a too short value. it's fixed 
now (thanks Fredrik and Larry)
- two more profiles (thanks Fredrik, thanks Larry)
- And I have suppressed my default profile... it has never well flewn :-)

release 2.0.7 :
- bug (?) correction : lack of precision of bridles after "A" resize --> now 
fixed (almost)
- add of "copy" menu to export the whole window to clipboard
- small modifications to export format to increse readability of A, B, C 
lines :-)

release 2.0.6 :
- bug correction : VRML rendering now OK for convex main body shapes (Thanks 
Mervin)
- C_C spacing text box easier to fill (thanks Tom)
- darker yellow for A profile plot --> it's for you Fredrik :-)


release 2.0.5 :
- help file updated
- number of C lines as a parameter
- C_C spacing between C lines as a parameter
- import/export modified consequently (lines "number of bridles added)
  PLEASE : add manualy these lines (for A , B and C bridles) in an exported 
file generated with a release before 2.0.4 of the exe.
- primaries lines length is now a parameter

release 2.0.4 : beta version

release 2.0.3 :
- VRML rendering of the NPW9b
- help file updated

release 2.0.2 : beta version

release 2.0.1 : beta version

release 2.0.0 :
- first public release of NPW9B calculator :-)

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profiles provided :

- Fredrik's Buzzard profiles : Buzzard _One_030622 wide and narrow --> see comments below
(The Buzzard wide being the default profile of my exe)
- Fredrik's Buzzard Vnose: Buzzard_Vnose_030817.NPW9B.txt --> see comments below
- BillsKite2003-01-18.NPW9B.txt : Bill's and Tom's profile --> not yet 
smooth BUT flies VERY well (see below) (congratulations Bill and Tom !!)
- Larry's profile Larry_2003-02-08.NPW9B.txt  --> see comments below

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NPW9 news group : www.topica.com/lists/npw9b
mailto this list : npw9b@topica.com

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Known bugs :

none for the while


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Tom's COMMENTS ON Bill's and Tom's profile :

I have attached to this the mail the export of the bridle measurements of my
Jan 17 flight.   Since there was no video associated with that flight due to
a snowstorm I will keep the name of 2003-01-08.   I have not "doctored" any
measurements to make profiles look smoother - here it is warts and all.
BTW :   The edge bridle spacing is 25.2cm.

Remember, with these measurments the kite flies wonderfully.   The window
seems to be about as good as I expected.   I will trim some of these values
to make a smoother profile for my next flight.   I also want to play around
with lengthening A1 and A2 to see what would happen.


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Comments from Fredrik to his ""Buzzard One" profile :

A few comments to the "Buzzard One" NPW9b Bridling:

* The development of the Buzzard One profile has been done with two goals in mind ; 
big flying window and good, controllable power. 
It has gotten increasingly thicker, which gives the kite a lot of wing properties 
- it develops plenty of power when on the move, regardless of flying direction. 
I think it now has many properties that makes it a good engine for buggying,
skiing and similar traction activities. 
Some of the wing properties, however, has been added at the expense of high speed all the way up to zenith 
(the flying window sideways, however, appears not to have been affected).
The Buzzard in its current form has a tendency to slow down and gradually
approach zenith - in some winds only approaching it with hesitation. This can
be eliminated easily, but so far only at the expense of some of the excellent
wing properties - those that make you able to modulate the power and generate
a steady pull by flying in figure 8's. 
I find this far more interesting and usable than optimizing the flying window against zenith. 
If you feel otherwise or want to experiment, please email me if you are interested in 
the details (address at the end of message).

* Please note that while it's important to be accurate with all bridle
lengths, it is perhaps even more important to be accurate when sewing the
darts on the nose. A slight error on each dart sums up to a bigger change in
the "total K" value and this sets the frontal curvature of the nose. Any
change of this curvature results in _big_ performance differences! 
My suggestion is to make preliminary darts, then measure the "top" of the nose
(which should be equal to the width B of the centre panel) and the "bottom"
of the nose carefully to see which total K value (the amount of shortening)
that the 5 darts have made _before_ sewing them permanently.

* There are currently two centre panel widths (measurement B) that are used
on the NPW9b kites. 
The Buzzard One bridling has been compared on two equally sized versions, 
one narrow and one wide, and the wider centre panel format of
B=2*A/3 was found to perform better. 
With this wider centre panel, I recommend the use of 5 (instead of 4) equally spaced darts, 
each with a width of the K value stated in the wide version Buzzard file. 
Note that in version 2.1.2 and later of J-P's exe, the program tells the difference between a 
wide and a narrow NPW9b and the number of darts (4 or 5) is clearly shown in the
graphics.

* All bridle lengths have been tested on low-stretch material (chikara/spectra/dacron) 
in the size of A=138 and 146 cm and therefore any radical change in
size and/or materials used might introduce a need for fine-tuning. 
The most common problems I found along the way of making the Buzzard profile are the
following:

a) Partial nose collapse on one corner when flying fast upwind, esp at an
  angle. The best cure for this (provided you are already flying the kite as a
  4-liner and always have some tension on the brake lines) is one that does not
  change the angle of attack and other performance parameters: Gently pull in
  bridles A2 and B1. This reduces the tension on A1 (which is where the
  collapse starts) and should be done a little at a time until the problem
  disappears. "A little" means that for A=150 cm you start by shortening A2
  and B1 with no more than 0.5 cm each.

b) Low "filling" of the sail when flying fast upwind, seen as a wrinkles
  across the width of the kite and a compression of the sail across the length
  of the kite. The first cure to try for this, one that doesn't change AoA or
  the balance between the brakelines, is to gently pull in B6. With "gently" 
  I mean that for A=150 cm you shorten B6 in steps of about 0.5 cm until the
  problem disappears. If necessary, tune the other B bridles slightly to
  obtain a smoothly curved B profile.


Please do not hesitate to contact me if you have any comments, questions or
suggestions: lejonklou@hotmail.com

I wish you the best of luck building and flying this great kite!
/Fredrik Lejonklou

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     Please take a minute and read these instructions for:
             The NPW9b Buzzard Vnose 2003-10-22

* Please note that while the default 'Buzzard One' profile
uses the standard NPW9b building and bridling method (as
described at Jean-Pierres site http://freedom2000.free.fr), the
Buzzard Vnose has a different bridling at the nose. This
results in less distorsion of the sail, especially when going
fast against the wind, and permits the use of a more wing-like
profile. The result is a kite with higher performance.
The Buzzard Vnose profile has:
- more controllable pull, mainly due to a very high top speed
- a larger flying window
- a more agressive flying style with better acceleration

* The Vnose modification (which in summary consist of
shortening A1 by T*1.5 and replacing two T-lines with Extra
lines in the length of T*3.3) that is described below is necessary
for all 'Vnose' profiles to fly, but it does not necessarily enhance
all NPW9b profiles.

* It is not necessary to cut and sew the nose part of the A
(centre) panel. There is very little stress on the T lines,
especially so with the Extra line bridling. Sew only the B and C
wing panels to the full length (including nose) A panel
including a reinforcement cord in all 4 seams and at the
perimeter, as described by J-P. Then sew a reinforcement cord
across the underside of the A panel, at the nose borderline
where the T's will be attached.

* Please make sure you are using version 2.1.2 or higher of
J-P's NPW calculator - then all measurements will be correctly
displayed. When sewing the 5 darts on the nose, be very careful
to keep the width at the specified K value. To keep the sum of
these 5 K's exactly right (this is important for the final
shape of the nose), my suggestion is to make preliminary darts,
then measure the "top" of the nose (which should be equal to
the width B of the centre panel) and the "bottom" of the nose
carefully to see which total K value (the amount of shortening)
that the 5 darts have made _before_ sewing them permanently.

* Finish the sail as described by J-P, cut and tie all bridles
to the sail except A1. Attach only the five middle T lines, do
_not_ use the first and last T lines that attach to the corners
of the nose! These are replaced by the Extra line described
below.

* Fit the Extra bridle line between the corner of the nose and
where the side dart is folded (in other words: from where
bridle A1 normally is attached to a point M-N/2 along the
leading edge towards point B1). This line should have the
length T*3.3.

* Tie bridle A1 around this Extra line with a bridle knot.
This knot should be able to slide on the Extra line so that A1
can find its optimal position by itself. Do not worry if the
knot later becomes very tight - the sliding is only needed for
the first flight.

* In order to compensate for the length of the Extra line, bridle
A1 has been shortened by T*1.5 in the profile. To see the actual
profile of the Buzzard Vnose in the JPG NPW calculator, add
T*1.5 to A1 by typing in value 162.50 at box A1 with A=138
cm. To correctly scale the size of the kite, keep the correct A1
value of 153.50 for A=138 cm, change the A (height) value to
the size you want and then manually calculate the Extra line as
T*3.3.

* The only bridle that in my experience may need some
fine-tuning is A1. Making it slightly longer makes the nose
more stable while making it shorter increases the powerful
wing-properties of the kite. Too short A1 makes the nose prone
to collapsing - make small adjustments (no more than 0.5 cm at
a time) until the nose is in balance. The older tuning tips
for the 'Buzzard One' does NOT work on the Buzzard Vnose.

* If using the cascade type of bridling, please note that the
default secondary bridles B5 and B6 are quite short compared
to the primaries. This can be seen in the air as a slight
compression of the distance B5-B6 and also B3-B4. Therefore,
try to round the primary lengths _down_ after scaling the kite,
by changing the values in the primary boxes to a nice and
even number.

* If you are the fast-building type, anxious to get in the air
as soon as possible, please note that certain details are more
important than others to get exactly right. These are: The 5
nose darts and T-lines, bridles A1, B1-B6, brakes and the
Extra line at the nose.

* All bridle lengths have been carefully tuned on kites made
of low stretch rip-stop fabrics (such as Chikara, Shikarex,
Icarex) and bridle lines of spectra (primaries) and dacron
(secondaries). Any combination of these or similar materials
should therefore result in a high performing kite.
If you are using more stretchy fabrics or lines, various
bridle lengths might need tuning for optimum performance.


Please do not hesitate to contact me if you have any comments,
questions or suggestions: lejonklou@hotmail.com

I wish you the best of luck building and flying this great kite!
/Fredrik Lejonklou

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Comments from Larry to his profile : READ IT -> interesting discussion

I went with a conventional bridle on this test kite as I thought it would be
easier to make any adjustments to the profile. My main reasons for building 
it
were to test out the theories of 4 darts vs. 5 darts in the nose and to test 
out
the effect of the T tie lengths. As it turns out I did not need to adjust 
any
bridle lengths at all (thanks for a sweet exe Tom it was perfect!) and the 
kite
was flown with three different lengths of T tie.

I am quite sure that any more 9b's I build will definitely have a cascade
bridle..........20 lines coming out of the power line Q Point is a pain in 
the
ass! It was a major headache trying to keep them tangle free and without 
twists
and criss-crossing during the bridling process.

So how did it fly..........see this page for photos that relate to the info
below!

http://users.mnsi.net/~lgreen/NPW9b.htm
(click on the thumbnails for a larger image)

I was originally going to test the theory of 4 vs. 5 nose darts on this kite 
as
well as the effect of lengthening the T ties. Well we sewed in the 4 darts 
on a
5 dart spacing (omitting the #3 or centre dart) with the idea that I could 
pin
the dart in place with safety pins, fly the kite, remove the safety pins and 
fly
again to see if it made any difference to the performance. However, in my 
rush
to get out of the door to fly it I forgot to put the safety pins in the bag 
with
the kite! So all the photos below were taken with only 4 darts in place!

I had originally set the T ties to the size in Tom's exe for a keel length 
of A
= 135 cm (i.e. T = 5.4 cm). When I took the kite outside to see if it would 
fill
I noticed that the nose looked very shallow and the sail did not stay filled 
at
all well (admittedly I was just hanging on to the Q Points at the time) so I
decided to extend the T ties by just over 1 cm before heading for the field.

Just for information, according to the 'Weather Network' info the weather
conditions yesterday afternoon were winds at 24 KPH, temperature -5°C,
wind-chill -12°C. However the winds were very gusty and by my estimation 
easily
exceeded 24 KPH!

T Ties at 6.5 cm

The 3 photos show the kite with the T ties at 6.5 cm. It filled nicely but 
was
prone to nose collapse and had a tendency to fly backwards rather than 
forwards.
The turning ability was not particularly hot either being sluggish and slow 
to
respond. The nasty looking loose ends in the photos are lots of spare line 
in
the 'loop backs' so that I can let out the bridles if necessary! Also note 
the
very flat looking nose in the middle shot!

T Ties at 7.5 cm

The  photo shows the kite with the T ties at 7.5 cm. This improved the
performance somewhat with increased pull, less nose collapse and better turn
rate. It also climbed better and approached (but not quite reached) the 
zenith.

T Ties at 8.5 cm

The 4 photos show the kite with the T ties at 8.5 cm. This was the final 
setting
for yesterday (I ran out of adjustment!) The difference in this last 1 cm
compared to the original setting is amazing! The kite pulls like crazy, has
excellent control, will perform 360° spins in its own length, will hover
anywhere in the window, will travel out to at least 80° to either side of 
the
centre of the window and it WILL fly up to the zenith! At one point Rick had 
it
hovering directly overhead and it was still trying to pull the handles out 
of
his hands! Only the wind blowing on the BACK of the nose and partially
collapsing it caused it to back off from 90° overhead!

Conclusions

This was an amazing first flight! This beast has way more pull than my 
similar
sized NPW5, it is faster across the window, much faster to climb and has 
much
more responsive controls. I am very impressed! The T ties DO need to be
lengthened from the dimensions on the plans and at the moment 8.5 cm seems 
like
a good figure for this size of kite.

Rick and I were both tired and cold after over an hour out there but boy did 
we
have FUN! When we landed it for the last time we both had grins from ear to 
ear
and 'high fived' each other like a couple of big kids!

The pull on this kite is something else......at one point Rick decided to 
try
'icekiting' across a frozen puddle in the middle of the field. Now this is 
only
a 2.5 M^2 kite and Rick weighs 290 lbs. It pulled him with ease across that 
ice
patch and we were only flying on 100 lb lines!!

To see how much effort we were putting into this test flight just have a 
look at
the 'lean back' angles in the photos which just show what we were able to
achieve with this little beauty!


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