Contact   Imprint   Advertising   Guidelines

Pansh Genesis and some tuning

For all foil kite riders
S2000kitesurfer
Medium Poster
Posts: 86
Joined: Wed Jul 17, 2019 6:50 pm
Local Beach: Poole sandbanks
Favorite Beaches: Mauritius le morne
Fuerteventura
Sardinia
Style: Moved to foiling
Gear: Flysurfer soul.
Brand Affiliation: None
Has thanked: 26 times
Been thanked: 27 times

Re: Pansh Genesis and some tuning

Postby S2000kitesurfer » Sun Mar 15, 2020 9:31 pm

Regis-de-giens wrote:
Sun Mar 15, 2020 6:27 pm
Of course i do speak of straight line for my formula.
Why should LD ratio vary with wind ? Not in theory if we stay in the same type of flow speed (this is actually all the interest and beauty of having created this LD ratio by the way) and if the kite is not too flemsy (it is not wrt profile deformation negligeable on LD ratio).

Believe it or not, it is a good way to assess wind, definitelly.

How fast the A15 turns on the video is also a sign of significant wind anyway. I know this kite ...
🙋🙋 The Kite in the video is on a 65cm bar with 21.5m lines .
Im just pointing out it hangs in lighter wind than my 12m flysurfer (which is very good). And also the flysurfer would of definitely overflown me in the same conditions .But Those conditions don't get any worse than that.
Looking forward to giving it ago . Seems more powerful than I thought it would be🙈🙈🙈🙋👍.

kiteykitekite
Frequent Poster
Posts: 271
Joined: Sun Mar 08, 2020 10:41 pm
Kiting since: 2020
Gear: Core kites
Brand Affiliation: None
Has thanked: 56 times
Been thanked: 32 times

Re: Pansh Genesis and some tuning

Postby kiteykitekite » Sun Mar 15, 2020 10:59 pm

It also has the jackomixer so that makes it turn much faster.

The best way I can explain it is kites have an amount of fixed AOA so they can not maintain best L/D beyond a point and then also because of the wind window, angles of attacks and speeds vary so much. There would have to be other effects airspeeds have on their soft and ram air structure too. The extreme example is single skins where they flap depowered. I have observed in lighter wind kites always seem to fly forward more which to me indicates better L/D (although maybe it
s inertia) and the speed change to wind does not seem to scale as L/D would dictate. I can only guess at what causes this but the window effect must be one thing. If kites could forever remain in the middle of the window at max speed then L/D should remain constant, but that is not true. All this is besides the fact that best L/D (or for me best upwind) related to riding is completely different, for that you have an optimum wind speed, no more and no less.
These users thanked the author kiteykitekite for the post:
S2000kitesurfer (Mon Mar 16, 2020 11:42 pm)
Rating: 8.33%

kiteykitekite
Frequent Poster
Posts: 271
Joined: Sun Mar 08, 2020 10:41 pm
Kiting since: 2020
Gear: Core kites
Brand Affiliation: None
Has thanked: 56 times
Been thanked: 32 times

Re: Pansh Genesis and some tuning

Postby kiteykitekite » Thu Mar 19, 2020 1:03 pm


Regis-de-giens
Very Frequent Poster
Posts: 1323
Joined: Thu Jul 31, 2014 2:58 pm
Weight: 62 kg
Local Beach: France: St Laurent du Var, Cannes, Almanarre
Style: 62 kg , light wind, waves
Gear: Conceptair pulsion 18&15&12S, OR Flite 10m , Airush One 9&6, peak 5M , Rally 6, Elf 11 &7, 19m2 single skin proto.
foil Ketos, RCS Supreme, TBK Mana, snowskis, kite-boat
Brand Affiliation: None
Has thanked: 72 times
Been thanked: 66 times

Re: Pansh Genesis and some tuning

Postby Regis-de-giens » Thu Mar 19, 2020 2:45 pm

kiteykitekite wrote:
Sun Mar 15, 2020 10:59 pm
I have observed in lighter wind kites always seem to fly forward more which to me indicates better L/D (although maybe it
s inertia) and the speed change to wind does not seem to scale as L/D would dictate. I can only guess at what causes this but the window effect must be one thing.
I do not observes that clearly, sorry , except in irregular wind / lulls or when the kite arrives to the zenith with a lot of speed, and in that case, it is inertia mainly ; inertia explains why in light wind you need to slow down the kite before it reaches the zenith by keeping a bit more pressure on rear lines ( and AoA increase to avoid frontstalls)

kiteykitekite wrote:
Sun Mar 15, 2020 10:59 pm
If kites could forever remain in the middle of the window at max speed then L/D should remain constant, but that is not true.
I do not understand your statement , could you detail what you call middle window in this case ?
kiteykitekite wrote:
Sun Mar 15, 2020 10:59 pm
best L/D (or for me best upwind) related to riding is completely different, for that you have an optimum wind speed, no more and no less.
best upwind is not linked to L/D ratio only; L/D ratio leads to optimum angle of traction, ok, but if it is in detriment of total pull through the lines, this can degrade the upwind speed ; hence you can sometimes go better upwind with a smaller L/D ratio if the kite is bigger for example; in other word, you can go better upwind with the same kite even if you sheet-in a bit more (than the AoA corresponding to maximum L/D ratio)

kiteykitekite
Frequent Poster
Posts: 271
Joined: Sun Mar 08, 2020 10:41 pm
Kiting since: 2020
Gear: Core kites
Brand Affiliation: None
Has thanked: 56 times
Been thanked: 32 times

Re: Pansh Genesis and some tuning

Postby kiteykitekite » Thu Mar 19, 2020 8:54 pm

So we can differ on observation sure. I must say since increasing depower on kites there is now a point where they sit further back in the wind where before they would stall. So maybe it is somewhere between 5-8kots they sit most forward, but depends on the kite.

Middle of the window is just that. Where the actual wind is perpendicular to the bottom of the kite. There the wind should simulate sink rate and speed should be a multiple of L/D to the wind.

Too many examples where the kite with general best L/D has the best upwind. Main example is race kites which are fast and with high AR, but also other fast kites in general. The confusion maybe with a fast kite is they need to be actively flown to produce maximum pull. A flown kite will always pull more than a static kite. Pull or lift squares with speed. It is why kites that are faster are better. There is some amount of sheeting with kites to increase the pull. In general there is a optimum AoA and camber for best L/D. On some kites there is weird effects from depower though. Certain kites flap or become C shaped, or LE dents, all diminishing L/D and slowing them down. For those sheeting a bit has a more dramatic effect on L/D.

The example where you go better upwind with worse L/D is where you always park the kite. Most kites are more designed like this because they are "easier". To me they are just trimming the range down. The faster kite has more top and low end, it's just the low end has the be flown more.

Regis-de-giens
Very Frequent Poster
Posts: 1323
Joined: Thu Jul 31, 2014 2:58 pm
Weight: 62 kg
Local Beach: France: St Laurent du Var, Cannes, Almanarre
Style: 62 kg , light wind, waves
Gear: Conceptair pulsion 18&15&12S, OR Flite 10m , Airush One 9&6, peak 5M , Rally 6, Elf 11 &7, 19m2 single skin proto.
foil Ketos, RCS Supreme, TBK Mana, snowskis, kite-boat
Brand Affiliation: None
Has thanked: 72 times
Been thanked: 66 times

Re: Pansh Genesis and some tuning

Postby Regis-de-giens » Fri Mar 20, 2020 10:17 am

just as an introduction for evrybody, L/D ratio depends on AoA, so when we talk about the L/D ratio of a kite, it is a "summary" ; its actually a curve depending on bar position , with a masximum , and sometimes people mixed the overall L/D ratio of a kite , with its "maximum L/D ratio" that happens only at one certain bar stroke. Lets call it the "max L/D ratio" in this message ; Hence a freeride kite can have a better L/D ratio than a race kite in certain conditions of use (if you sheet-in a lot the race kite for exemple).

I think we agree overall, but not on all ...
kiteykitekite wrote:
Thu Mar 19, 2020 8:54 pm
I must say since increasing depower on kites there is now a point where they sit further back in the wind where before they would stall. So maybe it is somewhere between 5-8kots they sit most forward, but depends on the kite.
Are you talking about depower stroke ( this I agree the L/D curve and max L/D ratio depends on AoA) or wind (unless you reach a very very low wind that leads to air lines detachments, then angle to zenith ( hence L/D ratio, which is the same) is overall constant on a standard wing
kiteykitekite wrote:
Thu Mar 19, 2020 8:54 pm
There the wind should simulate sink rate and speed should be a multiple of L/D to the wind.
Yes ok, that is was I was telling in the previous message with speed proportional to L/D ratio (max or curve) nand wind in the center of window.
kiteykitekite wrote:
Thu Mar 19, 2020 8:54 pm
Too many examples where the kite with general best L/D has the best upwind. Main example is race kites which are fast and with high AR, but also other fast kites in general. The confusion maybe with a fast kite is they need to be actively flown to produce maximum pull.
ok of course at equal pull in the lines, a higher L/D ratio will generate better upwind ; but .... at equal pull ... meaning if the wind is a bit lower, in lulls for example, you can obtain better upwind with a bigger lower L/D kite ; for two reasons:
-1 - you get more total pull, so even if the traction angle is worse, the effective pull ( total pull*cos of kite angle) remains higher ...
-2 - L/D ratio decreases very rapidly with increasing the AoA ; hence with a smaller kite you need to sheet-in, more AoA, so possibly less L/D ratio than a non race kite at its optimum AoA.

Here we talk about parked kite for sure ; as soon as you work the kite you loose a lot of upwind angle vs a bigger kite parked, even with worse max L/D ratio
kiteykitekite wrote:
Thu Mar 19, 2020 8:54 pm
A flown kite will always pull more than a static kite. Pull or lift squares with speed. It is why kites that are faster are better.
Yes
kiteykitekite wrote:
Thu Mar 19, 2020 8:54 pm
In general there is a optimum AoA and camber for best L/D.
yes and even not in general: always
kiteykitekite wrote:
Thu Mar 19, 2020 8:54 pm
The example where you go better upwind with worse L/D is where you always park the kite. Most kites are more designed like this because they are "easier". To me they are just trimming the range down. The faster kite has more top and low end, it's just the low end has the be flown more.
Yes parked kite , if powered enough , has a best upwind ... if powered enough ... and yes parking the kite leads to better angle of traction (not necessarily better L/D ratio intrinsequelly, but its flying decreases the angle of traction).
better low end for race yes if wind is not at the far bottom of the low end of the kite ; at the far low end ( freeride application, not race where you are overpowerd) you get better minimum waterstart and planning with a grunty kite rather than high L/D ratio.
kiteykitekite wrote:
Thu Mar 19, 2020 8:54 pm
.... seems we have lots most every readers interested by the genesis , sorry :argue:

kitexpert
Very Frequent Poster
Posts: 1024
Joined: Sun Aug 09, 2015 11:20 pm
Gear: many kites, also diy
Brand Affiliation: None
Has thanked: 21 times
Been thanked: 37 times

Re: Pansh Genesis and some tuning

Postby kitexpert » Fri Mar 20, 2020 2:12 pm

Flying kite through the WW doesn't reveal its L/D ratio for many reasons. Most obvious two is high inertia of (foil) kite and inability not to limit kite L with the weight of a kiter. Because of these reasons small kites fly much faster through the WW even if big kite has same shape and L/D.

Flying kite overhead and measuring how high it flies gives better results. Race kites are of course superior here. Kite weight is like drag, it restricts how high kite can fly. However weight is constant unlike L and D which are proportional to wind speed. This means weight is not that harmful in higher winds or when it is park-and-ride kiting well powered.

It is useful to estimate wind strength by looking how kite actually flies when you know your kite. Quite often in very low winds only way to find out if kiting is possible is to try it. In very low wind WW gets small and finally it will be difficult to keep kite flying.

Using different mixer can't make kite L/D ratio significantly better or worse as long as mixer does its basic job, which is to control AoA. Usual inventions or non standard mixers increase L in high AoA's, but then L/D is always low and not essential thing at all.

To try to prove mid AR kite having higher performance (for instance in very low winds) is a desperate task. If mid AR kite is "better" it is a user issue more than anything else. If comparison is made on hard surface mid AR kite always loses high AR kite (low end, upwind, speed, boosting). However there is some limit for having higher AR is not worth it, even if L/D rises other properties suffer too much.

Regis-de-giens
Very Frequent Poster
Posts: 1323
Joined: Thu Jul 31, 2014 2:58 pm
Weight: 62 kg
Local Beach: France: St Laurent du Var, Cannes, Almanarre
Style: 62 kg , light wind, waves
Gear: Conceptair pulsion 18&15&12S, OR Flite 10m , Airush One 9&6, peak 5M , Rally 6, Elf 11 &7, 19m2 single skin proto.
foil Ketos, RCS Supreme, TBK Mana, snowskis, kite-boat
Brand Affiliation: None
Has thanked: 72 times
Been thanked: 66 times

Re: Pansh Genesis and some tuning

Postby Regis-de-giens » Fri Mar 20, 2020 4:45 pm

I agree with your statement here ;

About last paragraph, I was talking on water where a boost is needed to ride , just commenting the sentence above : "The faster kite has more top and low end, it's just the low end has the be flown more" ; a faster kite can have a worse low end for freeride, if its not grunty or agile engouh for exemple ; for exemple the low end I can reach with the good Peter Lynn Aero 17m is not as good as my Pulsion 15m in term of minimum wind to ride. I can ride sooner but slower.

...and just to clarify again if needed (if it was oriented to my post ) : I never said a mid AR kite will be more performant ( too vague term IMO) ; I just said that if you are underpowered with a race kite, you can go faster upwind with a bigger mid At kite. Clearly .

Cheers

kiteykitekite
Frequent Poster
Posts: 271
Joined: Sun Mar 08, 2020 10:41 pm
Kiting since: 2020
Gear: Core kites
Brand Affiliation: None
Has thanked: 56 times
Been thanked: 32 times

Re: Pansh Genesis and some tuning

Postby kiteykitekite » Fri Mar 20, 2020 9:56 pm

So I feel the main point we disagree on is the kite with a faster speed or more L/D won't have as much pull as some potential lower L/D one, I guess like pulsion, below some wind. This I strongly disagree in that it couldn't go faster if it didn't create more pull. And all of my experience with faster vs slower kites too disagrees. Where you are likely right is the heavier kite with better L/D at some point the weight creates too much disadvantage for it and so it loses. I think it could be argued that the weight would somehow diminish the L/D.
Regis-de-giens wrote: you can obtain better upwind with a bigger lower L/D kite
So we should have to keep a constant comparing kites or their principles. Upwind depends on many things especially and most importantly the board. If we took at a high L/D kite and say increased the drag to reduce the L/D, say by adding a fifth line, or using thicker lines or even just running streamers off it, do you think now that kite with lower L/D would go upwind better? I think no, and my experience says no. Do you as well think that that kite would pull more flying in the window? I say no, my experience says no. So you could then argue that no it is some other special kite that has lower L/D but won't suffer the same consequence as to the kite we just tampered with. Well what other principles other than L/D do we have? Weight yes I will concede that is a factor and then total lift that is another factor. So lets tamper with the same kite, add 2kg to it. Is it worse in every possible way? yes. I am sure we agree on that. Now lets tamper another way with the same kite, we add some camber to increase the lift. This is an interesting point, the L/D is now maybe lower but does it go upwind better? My experience is usually no but maybe in some case yes and to that I would say you have likely increased the L/D. This is on kites where I have increased the camber and too seen a speed increase in the kite, but that is only a slight camber.

But if we look at info on paragliders with regard to sink rate. Lower sink rate equals more lift or pull. So for a paraglider the slight application of the brakes or Z lines results in the highest pull. It is only a slight change in sink rate 1m/s with brakes vs 1.1m/s without. The information for aircraft in general is the minimum sink rate is always slightly below the speed for maximum L/D. Now it is hard to find this info for many planes because they are only interested in maximum L/D or maximum glide ratio. But for gliders you can find this info, and the name of the graph of speed changing the sink rate is the "Polar curve". So lets look at some polar curves and more.

https://aviation.stackexchange.com/que ... s-related

So from that link this is the L/D graph and Polar curve for an aircraft caller the dg1000, a sailplane.


https://en.wikipedia.org/wiki/DG_Flugzeugbau_DG-1000

dg1000liftdrag.jpg
dg1000polarcurve.jpg
So both L/D and Lift(minimum sink rate) increase with speed and then drop off. You will note that peak L/D is about 10kph after peak lift or about 10% after. Then another interesting thing about these graphs is the effect of weight which would simulate changes in wind speed. So as weight or wind speed goes up, the speed for peak L/D increase which we already knew, but the total L/D increases too but only slightly, but even more interesting the peak lift speed increases, but also the peak lift seems to change with there being a higher peak in less wind speed but a quicker drop off and then a lower peak in higher wind speed but a slower drop off. But if we do some basic math and compare the wing loadings of 28kg/m2 vs 42.8kg/m2 we have 53% increase in wing loading, so if the sink rate was to remain constant there would have to be a 53% increase in lift. If we compare lift respectively we have about 0.5m/s vs 0.6m/s so a 20% increase in sink rate. So we increase the lift needed by 53% but only saw a effect of 20%. Without doing the math to resolve the actual change in lift I would say the lift has increased but not linearly with the speed increase or change in wind.

So the L/D or glide ratio for the DG1000 is 46.5 which is pretty high compared to kites, so lets compare different polars at different L/D.

So this is the ASK 21 glider a sailplane. It has a L/D of 34.5

https://en.wikipedia.org/wiki/Schleicher_ASK_21

https://aviation.stackexchange.com/ques ... ts-related

ASK21polarcurve.png
If you look the lower wing loading graph is cut off so we don't the early change we would expect and the wing loadings are not exact to compare between the ASK21 and the dg1000. If we look at the 28kg/m2 on the dg1000 at L/D of 46.5 its 0.5m/s sink at 80kph, wheres at 26.1kg/m2 on the ASK21 at L/D of 34.5 its 0.7m/s sink at 75kph. So its lower lift and lower speed with a lower L/D. But lets look at one more.

Boy it is hard to find this data on paragliders.

So the Agera RS L/D has no data but if we guess it from the below graph would be about 11.1 , 40kph is 11.1m/s divide 1m/s.

http://www.iparaglide.com/swing-paragli ... -en-c.html

http://www.swing.de/agera-rs-en.html
AGERA-RSpolarcurve.jpg
AGERA-RSpolarcurve.jpg (79.23 KiB) Viewed 306 times
So the wing used is likely the L at 29m2 wing area, it says "RS/L" but also from the weight specs. The weight is 122kg/29 is a wing loading of 4kg/m2.

It achieves a lowest sink rate of 1m/s at a speed of 35kph with a L/D of 11.1 compared to the dg1000 at L/D of 46.5 with its 0.5m/s sink at 80kph. The wing loading is drastically different though, 4kg/m2 vs 28kg/m2. We do know that increasing wing loading will increase sink rate but also increase speed. Should the paraglider have the same wing load the pattern is clear it would have a vastly worse sink rate. So we see a pattern that lower L/D makes less lift and at a lower speed.

So I hold the point that a faster kite has more pull, always :-)

Thankyou for reading

Regis-de-giens
Very Frequent Poster
Posts: 1323
Joined: Thu Jul 31, 2014 2:58 pm
Weight: 62 kg
Local Beach: France: St Laurent du Var, Cannes, Almanarre
Style: 62 kg , light wind, waves
Gear: Conceptair pulsion 18&15&12S, OR Flite 10m , Airush One 9&6, peak 5M , Rally 6, Elf 11 &7, 19m2 single skin proto.
foil Ketos, RCS Supreme, TBK Mana, snowskis, kite-boat
Brand Affiliation: None
Has thanked: 72 times
Been thanked: 66 times

Re: Pansh Genesis and some tuning

Postby Regis-de-giens » Fri Mar 20, 2020 11:35 pm

I must thank you for all the effort you put on your answer ; really ; it is a bit late for a complete answer tonight, but besides the documented information on those graphs, I just need maybe to precise my statements since they seem to be less opposite than what you think...
kiteykitekite wrote:
Fri Mar 20, 2020 9:56 pm
So I feel the main point we disagree on is the kite with a faster speed or more L/D won't have as much pull as some potential lower L/D one, I guess like pulsion, below some wind. This I strongly disagree in that it couldn't go faster if it didn't create more pull.
My point is more simple that you think and almost obvious : if you have a larger kite, even if less L/D ratio , you get more pull of it ; do you agree ? if yes you can go better upwind assuming the L/D is just better than a nasawing.
Now about your definition of "Low end" : for application on kiteboarding on water , and specially hydrofoiling, riding (in real conditions) is not just a matter of instant pull ... to get out of the water you need a pull during a certain time ; do you agree ? If yes, and assuming acceptable line length in the range of 30 meters and a similar kite surface, the limiting factor is often the time you get the pull to water start (get up on board then accelerate) ; and in that case ; a kite that pursue a good flying during a movement (loops or 8 moves) can be more efficient; and a high AR (which is a condition of high L/D ratio) goes in detriment of this pull during a turn. So low end is not always better with high L/D simply.
kiteykitekite wrote:
Fri Mar 20, 2020 9:56 pm
So I hold the point that a faster kite has more pull, always :-)
Yes, or a similar surface , and assuming a similar camber for example; I agree (from start ....) ; camber changes the game, otherwise camber on planes would never increase at the landing phase .... but again, as above quoted, a higher AR kite is not faster in turn for example, so not more powerful for the overall water start process.


Return to “Foil Kites”

Who is online

Users browsing this forum: No registered users and 4 guests