1: LIFT TO DRAG RATIO (L/D)
- Rams have a HUGE drag ("D") coefficient compared to inflatables, making them more inefficient. Ram air drag stems primarily from more friction at the "boundary layer"; ie the interface between air and the ram air kite is poorer because of more minute ripples in ram air kites. This is reflected in their poorer lift and inability to fly as close to the window's edge as inflatables. Large rams can pull steadily enough, but lack the aerodynamic finesse of good quality inflatables.
- Because large ram airs contain a much larger mass of air compared to inflatables within their pockets, inertia is HUGE. Large ram air kites contain OVER 11kg of air in their cells vs 2-3 kg for inflatables. It is very difficult to move this mass of air across the sky. This causes a multitude of problems including poor lift, slow turning, slow sining, and difficulty kitelooping. Excessive inertia also means that ram air kites to have a smaller "sweet spot" for unhooking, which is one of the reasons ram air kites are poor choices for wakestyle riding.
3: RIGIDITY, STABILITY, & FOIL SHAPE
- Semi-rigidity improves consistency, stability, turning, and handling. It means inflatables are able to withstand gusty conditions better than ram airs. Ram airs often fold, collapse, and twist in gusty conditions. Kite makers are always looking for ways to make kites more internally rigid, eg by joining the struts firmly to the leading edge, adding fifth lines, and bridles.
- For stability problems in ram airs stemming from lack of internal rigidity, see: http://www.foilzone.com/phpbb3/viewtopi ... sc&start=0
- Inflatables have a consistent foil shape because they are semi rigid. Rams deform and change their foil shape which causes an inconsistent aerodynamic profile.
- Far from being a hindrance, the tips of inflatable act as rudders, enabling faster, more controlled turns.
- When in the air, the semi rigid tips of inflatables create a "sled effect" leading to better stability and predictability. The sled effect is noticeably poorer in bow kites and ram airs.
- Rigidity facilitates turning. Bar input TWISTS the WHOLE kite, causing a rudder effect at the wing tips to accelerate turns. Lack of internal rigidity means that rams can't twist as aerodynamically as inflatos, meaning their turning and feedback feels sloppier and less precise.
5: LUFF CURVE/DEPTH PROFILE
- Luff curves vary extensively. Inflatables with flat luff curves sit forward in the window whereas inflatables with deeper luff curves sit further back in the window. It is the same principle as sailing: If you want more "bottom" end with a sail, you deepen the luff curve (eg letting out the outhaul on a sailboard). If you want more "high" end, you make the luff curve shallower (eg sheeting in the outhaul on a sailboard). There is a lot of difference amongst luff curves on kites; this determines a lot of handling differences. It's a matter of trying different inflatables until you find one you like.
- The excessive drag and inertia of ram airs causes them to sit further back in the window compared to inflatables. Also, when ram airs move too close to the side of the window, they start collapsing and deforming. Hence, there is less scope for ram designers to modify the luff curve.
- Because of the semi-rigid structure inherent to inflatables the luff curve is much easier to standardise and maintain.
- Ram lovers make a big issue of this. It isn't a big issue. Beginners find relaunching inflatables easy after a few sessions. Yes, some rams can reverse launch, but so what... a lot of inflatables can reverse launch. Rams can launch directly downwind in the water, but so what... so can a lot of inflatables. Anyway, downwind launches are dangerous for beginners because of the risk of being flung or dragged downwind. For intermediates and above, relaunching should not even be considered in the equation because a) they won't be dropping the kite much anyway and b) Relaunching inflatables is EASY. Commonly, ram airs will not relaunch properly because of twisting, bridle tangles, or waterlogging. These aren't such big problems with inflatables. See the threads below about ram airs sinking or becoming unlaunchable.
Inflatables are safer than ram airs because:
a) Downwind launches are bloody SCARY and can be dangerous. Eg viewtopic.php?f=1&t=2359529 . Because only a small bunch of slightly odd people use ram airs, there is confusion about their correct use, leading to potentially dangerous situations eg viewtopic.php?f=1&t=2360971
b) Because they lack internal rigidity, rams deform, twist, wineglass, and jellyfish in the middle of the power zone etc when they are downwind of obstacles, in rotors, and in VERY gusty conditions. This is VERY dangerous. Some of the most frightening kitemares seen have involved ram users in gusty conditions - their kites have been virtually uncontrollable and have endangered both the rider and other beach users.
c) Surf conditions
-- While it is always a gamble if your kite gets caught by a wave, at least you've got a fighting chance if it is an inflatable. If it is a ram air, it's all over.
8: BRIDLE TANGLES & FAILURES
Bridle tangles are disturbingly common with ram airs. Check this thread viewtopic.php?f=1&t=2354115&start=30
schmoe wrote: A bridle tangle on flysurfer can mean that you do not go out... For me I had many lost hours where the wind is cranking because of the bridles. I rather inflate 5 tubes and know that the setup time is exactly 10 minutes, no more no less, than have setup time that is 70% 5 minutes and 30% an hour. And now with one pump, the setup time of a tube is less, so it is not an advantage of the foil anymore.
Ram air bridle tangles can be very dangerous. A lot of riders have reported how their ram airs caught seaweed in their bridles, causing their kites to wineglass and spin out of control.
Bridle breakages occur surprisingly frequently with ram airs. They can be expensive (US $500 plus). eg "Flysurfer Warrior Exploding" viewtopic.php?t=4612
- Ram users struggle to pre-inflate their kites in a lot of situations eg cross- offshore conditions. I once witnessed a Flysurfer lover trying to launch at a point break in cross offshore conditions. He had to get a friend (inflatable rider) to grab one tip while he grabbed the other tip and they both ran up and down the narrow strip of beach, trying to pre-inflate - to no avail. He had to pack up and go home while the inflatable riders were able to do drift launches. Without pre-inflation, ram users find it very difficult to drift launch, a skill that is often required eg Promontory/headland launches.
- Contrary to the propaganda of ram lovers, ram airs and inflatos have similar lifespans. The major determinant of lifespan is obsolescence. In 2-3 years, whatever you're using now won't be worth much and will be superseded.
- Ram air repairs are generally a LOT more expensive eg viewtopic.php?t=4612 Trained PARACHUTE repairers are often needed, costing well over $1000. Bills over $1000 are common, eg viewtopic.php?f=1&t=2348790
- In the first example above, Flysurfer refused to honor the warranty, even though the kite was less than a year old.
Ram lovers frequently make ridiculous claims about upcoming competitions that they will "dominate." They then go on to get blown out of the water. For example, they said that various kites from Flysurfer (Psycho, Silver Arrow, Warrior, Voodoo, Titan, Insert Name Here..... etc) would dominate the pro kitesurfing circuit. It has never happened. No ram riders have ever made it into the top 20 on the PKRA http://www.prokitetour.com/ . Ram lovers said ram airs would dominate the Cabo Verde Wave event... They didn't. They said ram airs would dominate the "low-wind" showdown in San Diego - They didn't. The top pro riders ALL ride inflatables because of their superior aerodynamic properties. It's interesting that ALL the world records in hang-time, as well as unofficial records like Eric Eck's crazy jump, are held by inflatables.
13: LAND & SNOW
Check out this thread viewtopic.php?f=1&t=2355153 Not only are inflatables superior on water (because of better aerodynamic performance, jumping, stability, and safety), they are also superior on snow and land for the same reasons.
14: LIGHT WINDS
Ram airs are inferior light wind kites for the following reasons:
a) Excessive drag (bridles, lack of internal rigidity), compromising the Lift/Drag ratio
b) VERY slow turning
c) Inertia. The Speed 2 19 contains over 11kg of air in its pockets, compared to about 3kg in the largest inflatables.
d) Bridle failures and tangling
e) Wind dropouts and gear failure
--EVERYONE experiences a few gear failures (eg broken lines) and COMPLETE wind dropouts every year. You're usually safe with an inflatable. It can be used to "self-rescue" or you can swim in with the kite. If things go REALLY bad, you can just use the inflatable structure to support your weight, eg viewtopic.php?f=1&t=2368004
--ALL ram airs become hopelessly waterlogged after 45 minutes - unlaunchable and certainly unable to support your body weight.
-- The following is an example of "diraklib's" experience with ram airs in wind dropouts:
For the full admission, checkout the following link: viewtopic.php?f=1&t=2360979&start=40diraklib wrote:"the SA-19 is huge and can whack you silly if you let it get down wind of you in a low wind launch. It is downright scary - be ready with the QR at all times if not up and riding!!! I can't say I agree with claims that you can ride the SA-19 in anything lower than a steady 8 knots. I made a personal choice to not ride the SA-19 any more. It went down twice in lulls and managed to bow-tie on the way down - there was no way to relaunch. I was not as lucky as others that self rescued. My kite was full of water by the time I dragged my very tired and frustrated a$$ to shore. It sounds simple, "wrap the lines around the bar, fold the kite in half, roll it up on your board and paddle in"... noooo... there are lines everywhere under water that wrap around your feet as you are trying to manipulate the kite. You just pray that a gust won't pop the kite up and slice of an appendage. The kite ... is just too scary when it goes down. My attitude now is - if my LEI won't fly, I shouldn't be on the water. Anyone interested in a slightly used SA2-19m??? Cheap???"
-- The following is an example of FredBGG's experience with a line failure:
For the full admission viewtopic.php?f=1&t=2362065FredBGG wrote:The other day I had a front line fail.
Wind was slightly off shore...
I really needed a tow to the beach.
I had the kite safely on the 5th line folded in half (flysurfer Foil)
I waved down two kiters.... both expert judging by their riding.
Both refused to help.
One even yelled if you can't relaunch it's your problem.
Anyway after a difficult ordeal in the surf and current I got back to the beach.
I had to rest a bit but my board was still out there.
The problem here isn't with the other kiters, it's with Fred's choice of kite. If Fred had an inflatable, he would have been able to "self-rescue" by grabbing the tips and "sailing" to shore. The other kiters refusing to help is understandable: Fred made the choice to choose less safe equipment (ram airs - for self rescue) - it's his problem and he shouldn't impose on others to make up for the deficiencies in his equipment. Also, towing a Flysurfer to shore is like towing a sleeping bag full of water - horrible.
f) 8 knot limit
-- Despite what anybody tells you, you won't really have fun on any kite (ram air OR inflatable) unless the wind is over about 8 knots. This is the starting point for BOTH ram airs and inflatables, but because of the reasons I've outlined above, inflatables are vastly superior. And this is just the starting point. You won't really be having fun until it hits about 10 knots on an inflatable OR a ram air.
- Ram lovers have been shown to lie repeatedly about their light wind capabilities:
eg "jumping 8m in 8 knots" viewtopic.php?f=1&t=6349
gmb13 wrote:Please let me know which Kite you use that will allow me to get out in less than 5 knots. My Speed 3 19 DL gives up under 5 knots, so if you could please let me know about a flying tyre that will outdo my Speed3 please let me know - Gunnar Biniasch
NO kite - ram air or inflatable - will perform in under ~8 knots and NO KITE WILL PERFORM UNDER 5 KNOTS. The physics is complex, but primarily involves the power that wind moving at 7 knots (13km/h) can deliver. There is simply not enough power or velocity at this wind speed for ANY kite to perform.
Gunnar's exaggerations and lies can be found at viewtopic.php?f=1&t=2361421 This is typical of the ridiculous and unsubstantiated claims made by ram lovers. Kitesurfing in under 5 knots.......laughable.
g) Objective Testing
-- A variety of kites were tested in light wind conditions in San Diego a few years ago viewtopic.php?f=1&t=2319439&hilit=ram+airs+crash+in+san+diego . Despite the ridiculous over-hyped claims from Flysurfer reps like Ted Bautista, Flysurfer ram air kites crashed and burned. The overall consensus was that Flysurfer ram air kites are ok in light wind, but they turn VERY SLOWLY. The overall impression was that there are much better inflatables. It's interesting that a lot of the ram air guys who were excited about this showdown were remarkably SILENT afterwards, in particular, Ted Bautista, the U.S. rep for Flysurfer. His alpha-male chest-beating rants in the lead up to this showdown almost defied belief.
For an example of the LIES that ram lovers tell about their kites, checkout viewtopic.php?f=1&t=2350141&p=539227#p539227
h ) Flysurfer and Light Winds
See the thread about the poor light wind properties of Flysurfer viewtopic.php?f=1&t=2349064
i) Peter Frank's opinion
Peter Frank, a well respected commentator on the sport, says 8-9 knots is the bare minimum viewtopic.php?f=1&t=2365531
Peter_Frank wrote:Night_Thrasher wrote:What is the lowest wind condition I can go kitesurfing and what is the best kite brand and size for it?
It depends a lot on your weight, how low you can go.
If you are "average" around 80kg, the lowest you can go will be around 5m/s (10knots) with the right kite and board.
If you are REALLY experienced, you will be able to push the lower limit down to about 8-9 knots, but this is the absolute lowest wind possible to kitesurf in (holding ground/going upwind) with average weight IMO.
We are talking about 14-17m2 typical SLE kites and raceboards here
And talking about EXACTLY how "low you can go" is just pure bullshit - as you can not measure the windspeed at the kite, which is the only true value for this.
Sometimes you have a huge windgradient, sometimes a small one, and air temperature and height also influences.
But around 10knots is the limit for most kitesurfers, and just a small tad lower for the "extreme" ones
When you talk about windspeed - where is it measured then ?
At headheight, maybe around 2 meter above the water ?
Or at 10 meter height, which is our (Denmark) meterological standard height for wind measurements ?
There is a difference of typical 2 knots, so VERY important.
My point is - always take those claiming "this and that" as their minimum wind speed with a grain of salt
But the answer to your question would IMO be around or just below 10 knots measured at 2 meters height (in normal "summer" temperatures), and it is not dependant on brand, as many brands has excellent kites for this - and more and more has raceboards now too.
Amongst inflatable riders, there is a certain amount of collegiality. Inflatable riders tend to hang out together and help each other on the beach and on the water. If you fly a ram air, you'll always be a bit on the outside; regarded as a bit weird and not really part of the group. Part of this is because you will always be in a minority on the beach, part of it is because ram airs are so rare that inflatable riders are a scared/unsure of ram airs, and part of it is because, as a group, ram rides ARE a bit weird. Anyway, one of the problems with being part of a weird minority on the beach is that it can be very difficult to find people to help launch and land your kite, eg http://www.seabreeze.com.au/forums/Kite ... -on-beach/
Ignore the ram air propaganda. Ignore the lies. Ram airs are aerodynamically inferior to LEIs and nothing can change this.