Power Kite Forum

Arc inflation

power - 16-12-2009 at 09:57 PM

The user on this forum, herc, has posted some videos on youtube of the launching of his scorpion.
Eg. http://www.youtube.com/watch?v=GkolCdXajeE
He used a coleman quick pump to top it off after the wind did most of the work. One thing I noticed was it seemed like as soon as he pulled on the center lines, the kite rose up and after a quick jerk on the lines it was flying. When Maven and I were launching the 16m scorp, it seemed like you could just keep tugging on the center lines all day and the kite would never catch the wind. Part of that was the fact that we were flying in crappy inland wind, but my question is, how much does that extra top off on inflation with a pump help on the launch, particularly with the scorpions?

brplatz - 16-12-2009 at 10:08 PM

My synergy in light winds needs to be almost completely filled to launch correctly, if it launches at all....

IIRC the scorp is even harder to launch.

Brian

flyjump - 16-12-2009 at 10:14 PM

Every little bit matters with the scorpion. For some reason it needs as much as possible. I've never used the pump, but I usually zip it shut after in flation and push all the air to the far tip then unzip and fill to full. It seems to help keep up pressure to avoid the bowtie

flexiblade - 16-12-2009 at 10:14 PM

The center lines should have given you something of an upward direction of movement. I've launch my 10m guerilla in 5mph winds solely by using the center lines and tugging on them to get the tips to flap like the wings of a bird - got that bird up to zenith that way. What kind of winds were you trying to fly in? The 18m guerilla I have would be nearly impossible to get up in 5mph winds - just too much fabric.

As far as inflation - I've found that 3/4 full is fine to launch - 1/2 full (one side is still a little flat) will bowtie on you every time. Filling really comes down to how much wind you have on hand - good 12mph and up will be easy to fill the kite in less than 3 to 4 minutes. 5 to 10mph will take a bit longer making you impatient enough to try and launch a soft kite. So your problems were probably the winds you were trying to fly in.

power - 16-12-2009 at 10:25 PM

The winds were probably 10-12 on and off getting up to maybe 15. I think (at least from my short experience with one) that 3/4 full would cause a bowtie with the scorp every time. When I pulled on the center lines, it started migrating up at first, but then started turning sideways and bowtied and inverted and all that good stuff.
@flyjump- When you really get your 16m topped on inflation, does it launch like the one in the video?

lad - 16-12-2009 at 10:26 PM

Aren't the hi-AR Scorps the most the most susceptible to bowties of all arcs?

Do you hold in the control bar in half-way when launching?

Kamikuza - 16-12-2009 at 10:49 PM

I thought the Phantoms were ... AR of 6.5, Scorp has an AR of 5.5 although I'm sure there's more to it than that.

First time I tried to launch the Phantom in light winds, it bow-tied. I tried again, but it wouldn't rise about about 45 degrees and was steering like a bus in mud. Then I noticed that I hadn't closed the deflate zipper :D flew fine after that - needed a bit of a walk-backwards to get it in the air but otherwise, great!

flyjump - 16-12-2009 at 10:54 PM

I launch mine in a similar way but not exactly, I need to make a video on how to launch by yourself with a scorp. I have it down pretty good

Kamikuza - 16-12-2009 at 11:00 PM

Whoa just saw the launch at the end - that looked like a total downwind launch! Bit dangerous, no? I thought he'd take off towards the camera and was thinking he'd get the lines tangles up on his bags but he went totally the other way, back into the eye of the wind?

carltb - 17-12-2009 at 03:02 AM

the scorpion is the worst arc to launch. it need to be fully inflated not just 90% or it will bowtie. it also needs back line tension or it will bowtie. a gust on launch will cause a bowtie. once in the air they are great but getting them there isnt always straight forward.

lives2fly - 17-12-2009 at 03:53 AM

I flew my 13 m Venom last week for the first time in over a year. I didn't like it much on the water but its such an awesome landboarding kite! I never knew! think I will be flying it a lot more now.

I did get impatient waiting for it to fill in light wind - blew air in with a pump!

I dont think it helped much but it gave me something to do!

herc - 17-12-2009 at 08:02 AM

@power:
make sure you have backline extensions on the 16m scorpion. my first (and yet only - where is the wind?) launch of the scorpion 16m failed because i didnt had them and even my long throw naish bar had too short throw to proper release the backlines during launch

also, during low wind launch, alternating pulling the frontlines and putting back tension on the backlines helps. tugging frontlines accelerates and lifts the scorpion up, but provokes bowties. if you feel problems coming, just pull in the bar and put backline tension again, and the kite will stabilize and open up. of course, it then will fall back, so you have to alternate.

@kamikuza: with a 7 sqm scorpion, a downwind launch isnt that dangerous. also, the wind was just around 7-10 knots - nothing to fear :-)

PHREERIDER - 17-12-2009 at 08:05 AM

looked like plenty of breeze... did you need a fan?

herc - 17-12-2009 at 08:12 AM

@PHREERIDER: probably not, at least in this video. but to avoid any hassles i just 100% inflate with that fan. but i am sure that i now with more practise can also launch a scorpion not perfectly filled.
my personal observation: the small 7 sqm scorpion filles especially slow and bad. dont know why. maybe the internal mesh is too small? my new scorpion 16sqm filled much easier and much faster in comparable winds.

tridude - 17-12-2009 at 08:35 AM

after watching the launch the kite appeard to be 90 degrees off the wind direction.........this would account for a slow prefill............................and the pump is bad karma......................:lol::lol::duh::duh:

acampbell - 17-12-2009 at 09:37 AM

Quote:
Originally posted by Kamikuza
Whoa just saw the launch at the end - that looked like a total downwind launch! Bit dangerous, no? I thought he'd take off towards the camera and was thinking he'd get the lines tangles up on his bags but he went totally the other way, back into the eye of the wind?


Yeah, that was the strangest ARC launch I have seen. I had to click back and watch again a few times. I too was expecting it to go over the bags on the ground, past the camera and fly to the edge of the window.

I guess it's a variant of the landing axiom. "Any launch you can flay away from is a good one."

My 10m Scorp was my first ARC and I never knew at the time that it was supposed to be difficult, so I had no troubles except for snagging a sand bag and that has nothing to do with the Scorp.

power - 17-12-2009 at 09:59 AM

Thanks for the advice guys. @flyjump- Please post a video, that would be very helpful. @herc- I had the backline extensions on, and I think you were right about the tugging on the center lines. It does lift it but it does tend to provoke a bowtie as well. I'll have to try alternating between pulling the bar in and tugging on the center lines next time I go out. @lad- When I launched the scorp I completely let go of the bar and just pulled on the center lines. From what I'm reading that wasn't all right though.

carltb - 17-12-2009 at 10:05 AM

shudda bought the synergy!!!!

Maven454 - 17-12-2009 at 10:09 AM

He hasn't purchased anything yet.

flyjump - 17-12-2009 at 10:16 AM

What I do is I pull in the bar for the launch so it doesn't bowtie. While it's pulled in, I then tug on the front two lines to get it moving. Since the bar is still pulled in the speed helps the vents to open. After a guy taught me that I had very few failed launches. Make sure the sandbag doesn't snag a line and cause the tip to twist and cause the bowtie. When you launch make sure you're pulling on the leading edge line, not the trailing edge line! That caused a few mishaps in the beginning

f0rgiv3n - 17-12-2009 at 10:17 AM

Quote:
Originally posted by flyjump
What I do is I pull in the bar for the launch so it doesn't bowtie. While it's pulled in, I then tug on the front two lines to get it moving. Since the bar is still pulled in the speed helps the vents to open


I did the same exact thing to launch my scorp. It's quite funny at first but heck.. it works lol

power - 17-12-2009 at 10:28 AM

But pulling the bar in pulls on the rear lines...

Todd - 17-12-2009 at 11:27 AM

Hopefully if we don't get snowed in this weekend we can get a couple of kites in the air. Power, you up for that?

herc - 17-12-2009 at 11:44 AM

@power: if you only pulled on the front-lines, that explains why you were not able to launch. for some strange reason, this is definitely not possible with a scorpion (and maybe most other arcs?) you have to either put a well dosed continuous backline tension on the scorpion, or try to alternate. tug frontlines, till it raises, and observe the kite. just before it wants to collapse pull in the bar just a bit, so that the wind catches the whole sail and the thing opens up.

i wonder if a fifth line could help?
(this was discussed already here in the forum, but in the context of relaunch)
a 5th line must help to keep the kite open much better? also, wouldnt it help to face the air-intakes more to the wind?

i will do some tests soon, because i got another scorpion for cheap (100 euro). at this one i will test:

1. cutting away the grid at the air intakes and wrap up the air vents, such that they are completely open. then i will try to hot-launch it without prefilling :o

2. put a 5th linie or even a simple leadinig edge bridle on the kite

3. cutting away some of the internal mesh so that the air flow inside the kite gets better

4. attaching a long carbon spar to the leading edge (and maybe also to the trailing edge), to make a strange hybrid.
morphine style..

5. probably some more strange stuff

power - 17-12-2009 at 02:36 PM

Wow sounds like your seriousley modding it up. Let me know how that goes. @Todd- I'll definitely be available this weekend, I'm looking to get some snowkiting in if the forecast holds! Do you snowkite?

markite - 17-12-2009 at 05:37 PM

The Scorpions are definitely a twinskin of their own... well so was the hi-arc that wouldn't inflate at all...
anyway it's not all of them but certainly a good number that when launching without good internal pressure will have problems. If you are on the light end of the wind range, and they are partially inflated, they will only climb up about 25 degrees and sit there. no tugging on front lines will get them to climb and you have to watch the clam shelling and pulling too much to luff the kite. Even trying to turn it to fly to get some air inside and it won't respond well to steering - just teeters out in front. It takes a very gentle coaxing and as much pre filling as possible in light wind. Next is higher and gusty winds. Then you definitely need to keep rear line tension, not so much to stall it but to keep it from flying to fast forward then the soft nose drops down and rolls inward for the bowtie. You can get it to climb better but it's a good feel on the line tension and watching the kite to prepare for that overshooting and roll - or in a gust it'll do a sideways twist/bowtie.
New kites need the front screen/vents opened up because the material will be pasted together from shipping - pull all snorkle tubes open.
Watching the Scorpion fill and fly I've always wondered if the vent openings were just a little too high up on the leading edge. When the kite won't fill properly and it hangs out front the intakes are pointing upward and not getting air. Even when flying and a I do certain moves I see a slight dimple develop temporarily along the leading edge just below the intakes. So when the kite looses a bit of internal pressure after a surge in a gust, the dimple would indicate that is the centre of pressure along that edge and it's a bit below the intake ports. I've been tempted to reposition or mod the ports as well to see if that is one solution.
To me I would start at the first point on the kite and slowly work through the airflow process. If air isn't getting into the intakes to begin with improvements to cross venting aren't going to help.
Eventually you learn the quirks of the kite and things get better once they are stretched out but we still get some blown launches but limited to extremely gusty days .

power - 17-12-2009 at 05:45 PM

Thanks markite. What do you think of your 16 scorp?

markite - 17-12-2009 at 06:43 PM

Well I moved from Phantoms to the Scorpions when they first came out so first use was winter. The 16 size had a few quirks that winter launching but had great power speed and lift for winter. Then taking out to the water I had awesome sessions with it getting good air confident performance - but I've never never ditched it so I've personally never deal with a water relaunch on one (just the synergy in the drink), but have had friends get theirs rolled and twisted nicely in the waves. We are on the great lakes so when the winds up it's usually churning washing machine and gusty conditions.
Overall I like all twinskins on the upper ends of their wind range for best performance. Putting the kites on a long throw bar makes a big difference - ride with the bar out get the speed up and when you feel tight lines riding with the bar out that's when you send the kite fast and pull it in to get the big boost - bar out for kite speed first!
Then over the last 2 years inflatables have gained a lot more in depower and relaunch and ease of use so on the lighter end of the Scorp 16 wind range I found I was just having to work the bar too much so I don't use it on the water as much anymore and it's my land use kite and definitely one of most used winter kites riding it in some good blizzards and higher winds before going down to a smaller more manageable kite.
Despite the quirks it's a solid performing kite, not one I would recommend for first twinskin experience. They've moved down the food chain a little in my quiver. I do like the stiffer and quicker feel of the newer designs (Synergy and Chargers).