Power Kite Forum

The Mystery of the F-arc

Snake - 13-1-2013 at 11:10 PM

The F-arc, one of the best awesome low wind engines that exists. They were made over 10 years ago yet they have the record for fastest depower kite and go up wind better than almost any kite. Crazy lifty and amazing hangtime. Some call it a death trap, others a thing of beauty. What makes these kites so high preformance?

Aspect Ratio and profile. The combination of crazy high AR and a profile similar to a paraglider makes the F-arc have all it's crazy goodness. The profile is an important part of what makes a F-arc so high preformance, but the AR is what makes them what they are.

Twinskins lack of bridles makes them have unique characteristics. The 16m F-arc , with an AR of 7, does something strange when is gets moving.

Notice how the kite seems to open up once Hardwater starts moving. Using multiple spots in multiple videos to take measurements. I have calculated the AR of the kite in the arc shape when moving to be 5.625 with a projected area of just under 13m. Peter lynn himself states the S-arc flys with a near perfect arc. This is true for all arc except for the f-arc and maybe the phantom. If the f-arc flew with a perfect arc then it would have a projected area of 9.5m and an 4.43 AR when in the arc shape. My theory of why this happens is that the amount of shoulder the kite creates is proportional to the cord of the kite, not the area.

All of this means that the f-arc, when moveing, is equivalent to a lifty 13m kite without bridles. Bridles add alot of drag to a kite. One round bridle line creates as much drag as an airfoil 10x as thick. Being bridle-less the f-arc has less drag than a bridled foil. Less drag mean more prefomance and light wind power.

Kamikuza - 14-1-2013 at 05:06 AM

Could have saved some time by scanning the Arc faq :)

Bladerunner - 14-1-2013 at 05:48 PM

Fastest depower kite ? Can you expand on that ?

Snake - 14-1-2013 at 06:03 PM

Quote:
Originally posted by Kamikuza
Could have saved some time by scanning the Arc faq :)

The arc faq has very litle information on the f-arc. I got some of the data I needed from there like the span and cord of the kite. I have an experement that should prove my data that the f-arc is producing a higher than normal projected area. The problem is I don't have an F-arc:no:. I really want to get some f-arcs for low wind days. I have a few mods in mind that could improve the depower range and turning speed of this beast. A F-arc would also be the ultimate test for my anti-invert and anti-bowtie mod.:yes:

Kamikuza - 14-1-2013 at 10:35 PM

Feyd has/had one... or two...

Kamikuza - 14-1-2013 at 10:37 PM

Doh but I guess you know that already :lol: I'm suffering brain-farts cos I haven't had a good session to blow the crap out lately ;)

BeamerBob - 14-1-2013 at 11:19 PM

I have a 1200 I need to give some airtime the next appropriate wind day. Anxious to try it out and see what it's made of.

Snake - 15-1-2013 at 08:45 PM

I just found some vintage 2002 F-arc footage. The airtime is insane!!! I'd say the 16m has as much airtime as a speed 3. There is even some footage of the rare 9m version.
http://www.awindofchange.com/photo.html

Feyd - 16-1-2013 at 05:24 AM

I would not argue that the F-Arc has as much lift and glide as a Speed 3, maybe even more. And it will blow a Speed 3 away in an upwind run.

The Speed 3 comes out on top in downwind performance and wind range. The depow on the speed is much better as any modern production kite should be.

I saw a video around somewhere or the Kiwis flying F-arcs on water with handles in some pretty good surf. I have an old instruction manual around here somewhere that shows you the bar and handle options for F-Arcs.

I can't even imagine.

I hear a lot of people say that the F-arc generates minimal pull relative to it's forward speed. I would agree that is the case with the Phantom 1 but the F-arc, at least mine, generate some serious grunt at speed. If my edges are locked in it can still pull me off my line which none of the current Arcs (except maybe the CH1) are able to do very often.:roll:

Bladerunner - 16-1-2013 at 07:37 AM

Quote:
Originally posted by Feyd

I can't even imagine.

I hear a lot of people say that the F-arc generates minimal pull relative to it's forward speed. I would agree that is the case with the Phantom 1 but the F-arc, at least mine, generate some serious grunt at speed. If my edges are locked in it can still pull me off my line which none of the current Arcs (except maybe the CH1) are able to do very often.:roll:



This is why I question how this can be called the fastest depower ?

awindofchange - 16-1-2013 at 11:51 AM

The F-Arc has some pretty good depower, but you need to have long monkey arms to be able to use it. The depower throw was somewhere in the 2-3 foot range and steering was also rather slow compared to today's foils/kites. You needed a huge bar to really get the turning performance out of it. With a long bar and a huge depower line, the F-Arc was a kite that was well ahead of it's time.

The speed comes from the ultra thin profile, near flat trailing edge and 7+ aspect ratio. Not sure how PL did it, but that thing is incredibly fast!!!

Feyd - 16-1-2013 at 12:17 PM

AWOC is right. It has some amount of depow with a long throw bar. My Navi bar (large) works very well with the F-Arcs.

I had to tweak the F-Arcs leader lengths to work with my bar the way I want but it works great IMO.

In regards to "The world's fastest depower" I think "fastest REPORTED depower" or "fastest depower with a buggy" would be less controversial. There are a lot of people trying to go fast in the world and not everyone reports on every session. :rolleyes:

F-Arcs are very fast. When I first started playing with them I thought they would be a sweet easy way to set some new personal bests but it lacks the windrange and depower to do what I need it to do in the conditions I like to operate in. Now it's been relegated to use when I want a kite that just cranks in moderate winds, claws upwind like crazy and floats for days. It really is one of my all time favorites. Feels very much like a fixed bridle IMO. Turn rate isn't bad either.
:bouncy:
http://www.youtube.com/watch?v=FTLBuJIRwxM&feature=share...

One of the local Flysurfer disciples commented after taking a test ride on the 1200 his words were "You were cheating". This was after a day of moderate light winds in which I was smoking him and his S3 15m SA all over the place. He was very impressed.

awindofchange - 16-1-2013 at 04:29 PM

Love the video, awesome!!!

So let me get this straight...you were using 10 year old technology....and you were cheating?!?! :) Love it.

Snake - 16-1-2013 at 05:02 PM

Quote:
Originally posted by Bladerunner
This is why I question how this can be called the fastest depower ?


"Not for the faint hearted. (worlds fastest depower kite at 128kph)."

The excerpt directly from the Peter Lynn website. I don't think they would say that If it wern't true. Maybe they were on a dry lake bed with a buggy or under similar conditions.

I think PL should try a kite similar to the f-arc again. With the vpc and shaped panels they could drop the AR to about 6. With everything they have learned over the lat 10 year the could surely make an f-arc like kite with better relaunch and turnrate. PL really needs a low wind kite to compete with all the other brands and the f-arc fits the bill.

BeamerBob - 16-1-2013 at 07:51 PM

Well, they have a 22 and 24m arc available right now. Who do they say went 79 mph with an F arc? I know Brian Holgate got into the 70s with one last spring but I thought it was low to mid 70s.

Feyd - 16-1-2013 at 08:53 PM

Gav Mulvey. He told me about it in FB chat last summer. And my response was kinda the same and kinda in jest. But like I said, they claimed it.

The thing that intrests me about that is that he did his speed on a 9m arc. I do my speeds on a 10-12m arc. Holgate did his top speed on a 2.5m (?) FB foil. What does this mean exactly?

BeamerBob - 16-1-2013 at 11:35 PM

That is higher than the "official" buggy with depower record with PTW. Shame they don't submit it where all the records are kept. I guess that was in the speed buggy last April, right after NABX?

You are in a different element than buggies and kite size. Holgate was on a 2.7m Vapor FB race kite with winds gusting over 50 mph. It has the power similar to a 4-5m FB, but delivers it WAY out front. To compare, a 9m Phantom had a projected area of 5.7. With the right winds I can probably get over 60 with my 12m P II. I don't think I can handle it and stop and stuff with the more than 40 mph winds it would take to break 70. I'm still looking for it's limits though. Then there is still the 9 and 6m ones to find the limits of. I also need to put in some FB time for perspective now.

Feyd - 17-1-2013 at 05:48 AM

Thanks you for illustrating my point B.

It's an interesting thing. We've had this discussion of kite size/wind and the speeds we all get but one factor that you never mention is surface conditions. I'm going to guess that surface conditions for you on the playa are pretty constant?

To confuse things (for myself) further, I had a session on a 12m Ph2 and got a top speed was 72mph. I then switched to my 8m Charger 1, first time flying it, and managed 69mph. Winds hadn't changed much if at all and the variation in speed could easily be as simple as catching the right gust.

The stark difference was on the 12m I had to depower almost completely to fight my way up wind whereas the 8m I had to actually sine the kite to get the speeds that I did. What does this mean exactly?, I have no idea. :ticking:

BeamerBob - 17-1-2013 at 07:22 AM

I've found that the the more well powered the kite is, the better the upwind performance. Larger kites are more efficient with the wind. My problem is to have maximum "useable" power. Too much and I'm dragged sideways and downwind. Too safe on kite size and I'm missing speed.

Bladerunner - 17-1-2013 at 07:32 AM

72mph and 128KPH are not far apart ?

I was thinking that they may be refering to hard water with those speeds.

Feyd, what kite did you use when hitting your speed record ? How fast ?

Snake - 17-1-2013 at 08:30 PM

The f-arc has nothing compaired to the AR of this beast.

http://www.powerkiteforum.com/viewthread.php?tid=24660

Proletariat - 17-1-2013 at 09:59 PM

Hey! I have those same skis! I bought them on a lark for $50 with tons of camber left and they turned out to be fun as hell. Go Salomon!

Anyway, don't suppose anyone knows what the actual "perfect" shape of the f-arc is supposed to be? Is it an actual "arc" as in s*theta, or is it a parabola (y = x^2) or hyperbola (erm... some formula I don't recall offhand.)? Maybe a hyperbolic cosine (that's the shape of a chain hanging between two posts.)?

That f-arc looks incredibly challenging for a noobie. At the beginning, he's pumping the bar to keep it afloat and 3 seconds later it's whipping him along with no problem. Anyway, I was just curious, in case anyone knows.

Feyd - 18-1-2013 at 06:33 AM

I feel I should point out that the video that Snake has used as an example here is the very first time I took the 1600 for a ride. At this point I didn't have the pigtail lengths dialed in for my bar (see my leaders, shortened to off set wrong pigtail lengths) and I was very cautious with it being my first time out. The winds were very light that day for sure and it made it hard to get air into the Arc. But once she inflated I was amazed at the kite's performance.

It definately isn't a begginer kite. But in light winds it's a dream to fly.

The 1200 is the sweet spot tho =)

awindofchange - 18-1-2013 at 01:17 PM

The F-Arc is definitely quirky to fly and not something a beginner should NOT be starting out on. It has its attitude issues and because of the high aspect ratio, it can bowtie extremely easy when launching/landing etc... In light winds there is a mandatory technique that needs to be used to get it inflated and flying, it asks to be "pumped" by the front lines to get its long ribbon shape inflated but once it locks in, it is pure adrenaline.

I heard a rumor that there was a stash/stockpile of brand new F-Arc's available that were never released / sold on the open market. I am inquiring on a price on them right now and if we can work out a deal to get them here, I will offer the deal to PKF users.

If you are interested in picking up one (or more) of these bad boys, let me know and if we can get enough people interested, it makes the shipping much more affordable and we may be able to score a great deal.

Snake - 18-1-2013 at 04:17 PM

Kent, it would be awesome if you could get some f-arcs for everyone. I would want 1600 and a 1200. I also call dibs if they find a rare 900 :spin:. You should also see if they have any other old kites like venoms or phantoms. You should start a new thread to see how many people would be interested in getting an f-arc(s).

markite - 18-1-2013 at 04:37 PM

Quote:
Originally posted by Snake
You should also see if they have any other old kites like venoms or phantoms. You should start a new thread to see how many people would be interested in getting an f-arc(s).


haha is anyone else experiencing deja vu?

remember this whole thing a year or year and half ago when there were the last of the original Phantoms found and sold off and then a number of other things as well as the infamous F-Arc shipment that was supposed to be on it's way to Ricardo.
At that time there was also talk of the SLarc project and Peter had distributed a quantity of F Arcs around the world to hub people interested in the project. I was thinking the F-Arcs were pretty much accounted for with that dispersement but I did see the Peter Lynn New Zealand site offering some F arcs at the year end so maybe there are more coming to light?

Feyd - 18-1-2013 at 04:50 PM

I dunno, sounds like carnage in the making to me. :P


It's easy to get wrapped up in gear lust for a wing that does some amazing things. But Like Kent said it is NOT a kite for beginners and to be fair it's not a kite for a broad range of experienced kiters IMO. Don't get me wrong, I love my F-Arcs but my tastes and the environment I use them in is likely very different than 90% of the kiting population. The responses I got back from F-Arc owners (prior to getting the 2 I have) were by and large on the negative side. Most people who have them don't fly them either because they were immediately put off by the endless bowtie action or by the fierceness the kite posses when it turns on you. :evil:

I made some mistakes playing with mine before I got them dialed in and luckily cam out ahead. When you're out on a big patch of ice you have some room to make mistakes. It has some depower but compared to say and old Venom it has about 1/3rd the comparable depower IMO. Personally don't know if I would recommend these things to anyone that wasn't looking to absolutely haul ass.

BeamerBob - 18-1-2013 at 05:00 PM

Quote:
Originally posted by Feyd
Personally don't know if I would recommend these things to anyone that wasn't looking to absolutely haul ass.


:yes::ticking:

I feel better about being a little bit afraid of this thing. Not sure what to expect. Afraid I can't get it launched without a bowtie and invert. Gotta try next chance I get.

Feyd - 18-1-2013 at 05:24 PM

As long as your internal pressure is good it's easy.

Low air pressure, not so much but possible....

http://youtu.be/sdBV2njwwJg

And just because these words are from the man himself back in 2001 (shaking my head)

http://www.peterlynnkites.com/news/0112news.htm

BeamerBob - 18-1-2013 at 05:54 PM

You got away with way more issues than you actually had. I was jumping all over my seat watching the kite. Good job. I guess you were trying to get home under kite power after the wind went over the horizon with the sun.

Feyd - 18-1-2013 at 06:06 PM

I was 3 miles out from my anchor and the wind shuts OFF, completely when the sun sets. Seriously like someone flick a switch. The snow was about 1.5' deep with 8'' of slush underneath and I didn't bring my skins out with me so getting back was going to be a long hard process. My plan was to dump the kite and skis on one of the islands and hike back from island to island to avoid post holing in the snow/slush. Would add mileage but less fatigue. I could fly out and grab the kite/skis another day.

It was well below freezing so the slush snap freezes when it comes into contact with air above the snow. Adds 5lbs to each foot in a blink.

I was really, really motivated to get that kite in the air. :D

krumly - 19-1-2013 at 12:29 PM

Kent or Chris -

You've both probably flown the F-arc 1200 more than any of the others on here. I have flown mine both umodded and with a SLarc-type front bridle using a 60 cm bar with about 15" throw and 10" strap adjustment. I saw Kent's throw length comments above and wondered if that refers to the 1200. What do you think the total throw range is for a 1200; i.e., as if you were not using a depower strap and had ape arms to run it through it's full range?

My sense is that the Farc with a small chord and high aspect ratio just doesn't have the ability to use all its potential depower range with the standard Arc bridle-less set-up. The front bridle let's me lower the angle of attack and depower the kite more than is possible without it. It still steers like a truck. I wonder if the only way to improve that would be to go to a long, old-school bar, maybe 70-80 cm; or try a pulley bar like on the older bows and SLE's and deal with the higher bar pressure.

krumly

Snake - 21-1-2013 at 10:27 PM

I think I figured out why the F-arc opens up when flying. This weekend I noticed the kite opens up slightly when on the decent a of a jump. I after some research on aerodynamics I found the solution.

When you are falling, your decent is perpendicular to the true wind, createing apparent wind diagonally across the shoulder of the kite. Since the kite is in an arc shape, the curve of the kite slightly deflects the wind createing more lift in the shoulders than in the center, which causes the kite to change shape and and become more open. This can be applied to rideing horizontally also as you create apperent wind when you begin to move.

I will post some pictures tomarrow since this is really confuzing to understand.

bourgeois.jason - 22-1-2013 at 05:07 AM

Snake,

Here is what I thought when I first saw this post.

Assuming that the entire length of the kite has a profile like a wing (the top skin is longer than the bottom skin as the air travels over it), this would create lift throughout the length of the kite. As the speed of the air passing over the foil increases , it will create a force that is perpendicular to the skin at any place you measure it. It is easy to understand that the middle of the kite creates lift, but the same force that creates lift on the middle of the kite will also push the edges out. This force is counteracted by the strings. If you had really short strings, lets say 10m, the kite would not be able to flex out as much because the strings are trying to pull the kite closed. If you had really long strings, like 40m, the kite would not really notice the strings pulling it closed, but it would still never go straight because the middle of the kite is not supported by bridles. Since the ends of the kite are the only parts with a counter force, the kite will always be bowed.

SKMBT_C28013012212510 - Copy - Copy.jpg - 110kB

Snake - 22-1-2013 at 08:13 PM

Jason, your theory is close but not quite right. An arc will always fly in a near perfect semi-circle when it is stationary. When the wind speed increases, the lift everywhere on the kite increases, so the kites shape stays the same.

The reason the kite opens up when the apparent wind starts to develop is because there is another force acting on the shoulders of the kite. The apparent wind moves over shoulders diagonally at the angle of the lift to drag ratio. This causes the the curve of the arc shape to deflect some air, which, according to newtons 3rd law, causes the kite to react in an opposite direction, which is outwards. This causes there to be more lift in the wingtips, changing the shape of the kite to have more projected area.

My original observation in the first post is backed up by theory. I used a lift to drag ratio of 8 to do my calculations. This gave me an additional 3.55 degrees of deflection which increases the lift 35.5% in the shoulders. This in tern causes the kite to open up to a projected area of 12.8725m, not far off from my inital guess of 13m.

This picture shows how the extra lift is created. The air (black arrows) curves around the skin of the kite (blue arc), which pulls the wingtips outwards.


This picture shows the kite (orange box) from the side. The red arrow is the true wind, the blue arrow is the apparent wind, and the black arrow is the the wind created from forward movement. The blue line shows how the wind flows over the shoulder of the kite. The angle of the apparent wind is drawn much steeper than what it would be to help illustrate how the wind is flowing.

bourgeois.jason - 23-1-2013 at 12:16 AM

Snake,

Can you please let me know what calculation you used? What assumptions did you use? How did you model the kite?

Since I don't know the answers to those questions, I cannot comment on most of your post; however, I am mostly interested in hearing your explanation for "the lift everywhere on the kite increases, so the kites shape stays the same." My diagram shows that as the air moves faster over the foil, the forces acting perpendicular to the foil at any given section increase. This is what I theorize opens up the kite. There are other factors, but when someone is moving 40 mph in 20 mph winds, the apparent wind takes on a significant role in the shape of the kite. I do realize, however, that the force of lift at the center of the kite may very well be too great for the edges to deflect due to apparent wind alone, which is where your assumptions may complete the picture.

It would be interesting to hear a kite designer's input on this. I don't have any experience in that area.

-Jason

BeamerBob - 23-1-2013 at 09:43 AM

In the real world, an arc tends to compress a bit as the wind increases. They can "flair" if the wind suddenly drops. Gusts tend to cause the tips to come together while the kite elongates. The bulk of the wind pressure on the kite hits the "projected area", which causes the kite to slightly elongate in higher wind or apparent wind due to airspeed.

pbc - 23-1-2013 at 12:13 PM

What Bob describes is what I see. It seems to be the visual manifestation of the gust response we feel--more wind reduces the projected area.

Philip

Bladerunner - 23-1-2013 at 06:59 PM

Bob explains what I have experienced. They stronger the wind the tighter my projected area. Opening in lulls. Clapping in crap.

pbc - 23-1-2013 at 08:12 PM

There's not much worse to an Arc flyer than a case of the clap.

Snake - 23-1-2013 at 09:00 PM

I have notices my Venom loses some area when the wind is strong. I am pretty sure this is from PL reduceing lift in the wing tips to gain speed. That is why chargers had the clapping problem. Old S-arcs F-arcs have the same profile through out which means eqaul lift through out. The S-arc has smaller tips than the center so it also has some list lift in the shoulders. That is why older Arcs are more stable and slower than the new Arcs. This also means that the angled wind makes the kite have more lift in the shoulders in than the center. F-arcs are the only kite I have ever seen this happen on and I think it is the only one that does this.

Jason, say the kite is above your head and the wind is 15mph. The kite will be in a semi-circle shape because in that shape the shoulder lift and the center lift are balanced. If the wind doubles to 30mph, the kite have 4x the pull. The pull will increase the same everywhere equaly on the kite so the shape wil be the same.

BeamerBob - 23-1-2013 at 09:45 PM

There might be some slight pressure on the wing tips for stabilization and autozenith but there isn't any significant lift coming from the sides of the kite. Something was pushed to the limit at the wingtips on the charger and so it had the tipclap issues in some conditions.

first winter session with F-arc

mdpminc - 27-1-2013 at 08:38 AM

Quote:
Originally posted by Feyd
It definately isn't a begginer kite. But in light winds it's a dream to fly. The 1200 is the sweet ......


Yesterday I had my first winter session (not counting surfing session just two weeks earlier, yes surfing in Ontario in January)
Wind was light 8-10 knts, 3"powder on top of 2" harder gritty stuff, "snowkite" Nobile board.
I had three choices to fly; Aurora 15m, JN Luis 10m and F-1200.
Wind was light maybe too light, but I remember one of the Feyd's posting regarding low wind performance of the F-arcs.
So decided to try the F-arc, middle zipper only, so only half inflated, got it filled with "Scorpion" technique; ie praying hard for it not to bowtie, a success, inflated fully.
I had it on a "navigator" copy 56cm bar with 28m lines and 45cm bar travel.
Boy..., this thing wants to go and wants to fast. Apparent wind wow...it felt like I was going twice or more the wind speed (no gps to verify)
Very stable, really quick turning, and upwind like no other.
I found it really likes to fly with almost no rear line tension, I was trimmed all the way in, so power management was in bottom 1/4 of the bar travel.

Long story short I was amazed how much fun I had flying it. If one can get past the occasional bowties and limited depower (~50%) it is a truly an amazing kite to fly. It does not show its age at all
Can't wait to try it on water next.......

Snake - 27-1-2013 at 08:35 PM

Not to sound rude mdpminc, but how much do you weigh? And how would you say it compairs to your your phanny and your scorp?

Feyd - 28-1-2013 at 05:35 AM

Jeeeeeze Snake you NEVER ask a lady her weight. Not in public anyway:lol:

That's a great description of your session mdpminc. I'm glad you had a such a great time on the F-arc. Works very well with the Navigator bar's throw I think.

@ Krumly I suspect you are right about the limited depower of the F-Arc. At the time it was designed I don't know that they really put as much consideration into the depow as they do in "modern" kites. I think the focus was probably more on pushing the powered performance. WHich I think they did quite well.:roll:

The "holy grail" is to get a kite that has mad performance but can be depowered signifigantly when needed. There always seems to be a trade off IMO.

I've got mine set up so that it is slightly oversheeted and I rely on heavy stall as a means of power management and trimming to fine tune but I deal with the F-Arc like it's a fixed bridle using the brakes to slow it down when needed.

To me it generates power like a fixed bridle but still, like mdpminc say's it gets about 50 (maybe 40) percent depow when you need it. The longer bar throw is key to getting some depow out of her. A bar like an '04 or -07 PL won't work nearly as well w/o some modification IMO.

I've been thinking about how to get her to turn faster w/o having to muscle float turns. The pulley bar may be one route would try, the long 70cm bar is just a way for me to put my helmet to work as I always whack myself in the head with bars that long. I've been considering putting together a steering system similar to waht came on the Flexi, Sabre MK1. It had a crossover line than worked similar to a pulley bar. It seemed convoluted at the time but as I reflect it was actually pretty elegant.

After reading mdpminc's post I'm going to make an effort to get out on the F-Arcs today I think. :evil:

Feyd - 28-1-2013 at 05:40 AM

In answer to the question how does the F-Arc compare to a Phantom or Scorp I would say that the Scorp is an excellent teacher for handling skills that translate well to the F-Arc. FLying wise they aren't even close. The Phantom, tho sharing the same AR as the 1200 is so detuned and docile there's no real comparison. IMO.

Bladerunner - 28-1-2013 at 07:38 AM

Has anybody ever considered putting a VPC bridle on an Farc?

mdpminc - 28-1-2013 at 08:38 AM

Quote:
Originally posted by Snake
Not to sound rude mdpminc, but how much do you weigh? And how would you say it compairs to your your phanny and your scorp?


not to be rude :-) 207lbs naked, 230lbs in winter gear


Quote:
Originally posted by Feyd
In answer to the question how does the F-Arc compare to a Phantom or Scorp I would say that the Scorp is an excellent teacher for handling skills that translate well to the F-Arc. FLying wise they aren't even close. The Phantom, tho sharing the same AR as the 1200 is so detuned and docile there's no real comparison. IMO.


As Feyd said.......and to add it takes same amount of muscle to get the P2-15m to turn fast as it did 1200.

mdpminc - 28-1-2013 at 08:42 AM

Quote:
Originally posted by Bladerunner
Has anybody ever considered putting a VPC bridle on an Farc?


I think "dog ears" would have to be removed to attach VPC, but could be worth to try it.
Anyone outhere with a 1600 that is collecting dust in their garage, I could dust it off for you and try the VPC thing on that :saint:

I'll leave 1200 as is, it just flies perfect the way it is.

Feyd - 28-1-2013 at 08:48 AM

I've been talking with some people about that and there is some thought that a VPC on such a hi AR wing may be more of a detriment than a benefit.

I'm with mdpminc, I was going to remove the dog ears on my 1200 in hopes of getting rid of flutter and gaining some of the performance that removing the ears is supposed to offer but damn the kite flies so nice I just don't want to mess with it.

The 1600 is so long and thin I think if you threw a VPC on it, you would have half the kite halfway through a turn before the other half even knew what was going on.

Unlike mdpminc, I won't fly it naked to get the extra performance out of it. :wee:

mdpminc - 28-1-2013 at 08:57 AM

Quote:
Originally posted by Feyd
....... I was going to remove the dog ears on my 1200 in hopes of getting rid of flutter and gaining some of the performance that removing the ears is supposed to offer but damn the kite flies so nice I just don't want to mess with it..........


I was thinking to saw-in thin fiberglass battens (similar to what Waroo had on trailing edge) to stabilize the ears, maybe that would help, but I only observed the flutter during harder turns and none really during straight flight.

Snake - 29-1-2013 at 11:19 PM

Quote:
Originally posted by Feyd


I've been thinking about how to get her to turn faster w/o having to muscle float turns. The pulley bar may be one route would try, the long 70cm bar is just a way for me to put my helmet to work as I always whack myself in the head with bars that long. I've been considering putting together a steering system similar to waht came on the Flexi, Sabre MK1. It had a crossover line than worked similar to a pulley bar. It seemed convoluted at the time but as I reflect it was actually pretty elegant.



Feyd, I looked up the sabre and it has a normal depower bar. Is the crossover in the bridles? Pully bars work well for better depower and turning but at the cost of double the bar pressure and less direct feedback from the kite. I have an idea for a bar that would keep everything the same but speed up the turning. I'll mod my bar and try it out on my venom this weekend.:wee:

herc - 31-1-2013 at 08:17 AM

thinking out of the box, ULS System could be the answer to enforce control over the F-Arc:

http://vimeo.com/30119969

the idea is to remove the bar. a bar limits the massive action and depower range of your arms. a bar limits the left/right difference needed for steering. simple solution: get rid of this thing. control the kite "paraglider style" with brake handles for each arm. only drawback: no more single handed riding.



of course on normal length lines for the f-arc or other kites.

i will try the same system with my new sliding ring harness.

Snake - 15-3-2013 at 04:50 PM

I was doing some more reasearch one the F-arc being I am getting some (thanks again kent!)and found some more interesting info. Peter lynn made an F-arc 2. It was marketed toward land use because of the high AR. Though the days of one color fabric and calling them "Arcs" was over so they came up with new name. The Phantom. It was interesting reading what was said about the prototype from a test rider. "I was disappointed with the bottom
end of the F2 16". That was in the first sentence. Reminds me of what Feyd said once, The Phantom is the F-arc with it's balls cut off. This seems to be the case from everything I have read. Prefomance and raw power was traded for relaunch and depower.

http://sports.groups.yahoo.com/group/arcusers/message/7423

http://www.powerkiteshop.com/news/peterlynnfarc.htm

Bladerunner - 15-3-2013 at 05:10 PM

On the ultra short line thing.

I see how this method gives you greater depower / turning etc. but I don't think you could jump worth a bean ? Glide, yes but how do you send it ? It would certainly be a safer way to kite but this is about the Farc , not the safer way to fly ! Something tells me that's not the Mod' that Snake is after! ;-)

doneski - 16-3-2013 at 09:46 AM

I agree with Herc; remove the bar to get massive throw lengths/depower on the brake lines.

Here's a vid that shows this better than the one Herc used. He's probably too modest to use this one:
http://www.youtube.com/watch?v=LKDroQGIq7c

What about running a line from the handles to the chickenloop so you can let go?
What about making the handles attachable like Bobalooie's so you can fly single handed?

Feyd - 17-3-2013 at 04:52 AM

I was out the other day and got caught in high winds while flying an 11m Apex 4. It had gotten to the point where I exhausted the trim range and couldn't hold position at the edge of the window. I flew her to a wind shadow, landed and shortened my lines to 12m.

With 12m lines I shaved a lot of power off but it was still very capable of jumping. With the short lines she snaps a turn like plenty fast to jump with. Redirecting my tacks was a difficult to manage without getting lofted a little. The windspeed could have been a strong influence in that tho.

If the lines were much shorter, I think the kite would be getting choked out.

Very cool video there Herc.

krumly - 18-3-2013 at 08:53 PM

I am going to try removing the bar ala Herc's set-up on my front-bridled FArc1200.

The kite will fly on a single front line with a Y divider and rears detached, for a bit. But steering input is non- existent with a bar, even a long bar with long throw and long trim strap. Seems to me a front bridle is the only way to get even more depower out of the kite - it moves the front line attachment points further forward. Having control of the rears with separate handles and lots of throw may be the only way to be able to get steering input.

krumly

awindofchange - 19-3-2013 at 12:20 PM

We use to ride with what was called a "free bar" setup. Basically you take the center depower line out of the center of the bar and move the bar above the line. Then attach the bar to the center line with a small insignificant bungee or line (in case you accidentally drop the bar). This gives you control bar type control with unlimited depower (at least as long as your arms are), you can still ride one handed by moving your hand towards the center of the bar and you still maintain all the safety features.

herc - 19-3-2013 at 12:57 PM

@krumly: i am very interested in your results with steering the bridled F-Arc using free-brakes.

@windofchange: a free bar is for sure a very good idea ! i must try that out.

in the meantime, i have improved my setup using better grip - handles and some bungee cord to attach the break lines to the sides of the harness. btw, the handles are the wood grips from corkscrewers :-) anatomically perfect !
i have also added additional grip positions with two small aluminum tubes and two bottle caps.

here are some pictures:

https://picasaweb.google.com/111510368262264907350/19Marz201...

zero gee - 19-3-2013 at 01:17 PM

Personally, I never liked the freebar setups for small, faster kites (15m and smaller at the time). The bar type was a little better. They also look more complicated than just a conventional bar. It was way too easy to stall the kite (killing the power, made for uneven power) and too hard to just relax when riding with it. Might be better for the slow, super sized kites though. I never had anything that big and slow to try it out on though.

Snake - 10-5-2013 at 03:43 PM

I've flown theses kites quite a bit lately and have noticed some quirks. Firstly, they do not like going downwind. They lose most of there pull and speed even if you go a little bit downwind. They prefer you go slightly upwind. They also like to "load". If you add a bit of resistance, such as sliding, The kite will generate massive pull. I slid 20 feet past where I normally stop with my venom and hit a path. I got a pretty huge scrape on my ankle from that. That's about it that I found that hasn't been mentioned already.

elfasa - 11-5-2013 at 02:48 AM

There was a F arc 1200 on ebay in the UK recently. Went for £50 ! :o Was KO, but I was really tempted to bid. Probably would have done if I didn't think it was going to go for more..

Tim

Snake - 11-6-2013 at 11:46 PM

Does any one else have one of these bad boys? I'm loving mine. I have a plan for a vpc for the 1200. I'm not sure it the 1600 would like a vpc because it can be bowtied by turning really hard (like garbing the leaders hard).

Carl, I think you need a pair of them, or at least a 1200. Then we could see how they stack up against new arcs for freestyle. Mine boost huge and seem to do well, but I am nowhere near the level that you are.

Feyd - 16-6-2013 at 10:21 AM

Yarding a hard turn on the 1600 shouldn't cause it to bowtie. Ycan reach over steer it at the end of the leader to snap a turn and it will respond without issues.

Comparing F-Arcs to a modern Freestyle kite is apples and oranges. The F-Arc can send it to the moon but Kite looping it is a total PITA and turn rate, unless you have th muscle to snap the turn, is not even close to say a CH2.

The Farc is closer to race kite than a freestyle rig.

Snake - 16-6-2013 at 04:47 PM

Feyd- I pulled the leader so hard it took tension off the front line. I almost never have to do that but the kite was on a dive directly into the ground. The shoulder curled in and it fell to the ground. It was more user error than the kites fault.

As for freestyle I'd say it's pretty good. Don't expect to be busting kite loops or riding unhooked. For basic jumps with technical maneuvers, like board-offs and spins, It should rock. It has plenty of lift and float to allow things like that.

Feyd - 17-6-2013 at 03:28 PM

Still seems odd to me to have that reaction to yarding the leader.

The F-Arc flies unhooked very well. FUn to play around with, (not like I'm doing huge handle passes or anything) but it give you the feel of an old school fised bridle. Love that raw power.

It's got plenty of lift and hangtime for board offs. :D