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Which Stab for the 720?

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NYKiter
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Which Stab for the 720?

Postby NYKiter » Sat Feb 08, 2020 3:02 am

Finally could afford to get my hands on a 720 and have yet to ride it.

I have a 483, 450 and 325 stab....which would be best for it?

Thanks

:cheer: :cheer: :cheer:

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Re: Which Stab for the 720?

Postby Peter_Frank » Sat Feb 08, 2020 8:39 am

There is no such thing as a "best" stab for a hydrofoil.

It is personal preferences only.

Do you want a more stable combo, or do you want it more lively (smaller stab)

Some like a tad more stability for jumping or tricks, some want more agility for riding waves or tricks.

A few ride without the stab :naughty:

Just try yourself to find what you prefer, or pick the largest if you have no idea :wink:

8) Peter

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Re: Which Stab for the 720?

Postby gmb13 » Sat Feb 08, 2020 11:29 am

NYKiter wrote:
Sat Feb 08, 2020 3:02 am
Finally could afford to get my hands on a 720 and have yet to ride it.

I have a 483, 450 and 325 stab....which would be best for it?

Thanks

:cheer: :cheer: :cheer:
I really depends on your preference. If you want it super loose and agile then the 325. 450 will give you the most stability in all axis and have the pressure point quite far forward. The 483 gives a more balanced stabilisation, and allows for a bit of sideways slip in turns.

My personal favourite for the 720 is the s420. It's fast and loose, but not as loose as the 325.

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Re: Which Stab for the 720?

Postby NYKiter » Mon Mar 02, 2020 6:20 pm

I finally rode the 720 with the 483 stab today.

The wing can definitely go as slow as the 633 and 683 without stalling which is rather crazy....

Its also definitely has a little less roll stability, which is expected...but it felt twitchy (or more responsive?) and it seems to handle fast drops better (small swells...not real waves).

I found that I had to be way up on the front as the wing sits at the nose...

To me it doesnt like to go screaming down wind while riding flat...it likes to go from edge to edge.....so as long as I was edging roll stability was better..

I do believe the 683 goes a little quicker than the 633, but Im not seeing any significant increase in speed between the 683 and the 720...

Im sure the 450 stab would make it go at lightning speed but Im not interested in the roll stability tradeoff.....

Seemed to carve hard turns MUCH better than the 683 and it went upwind WAY better......

Just my first take on the 720...

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Re: Which Stab for the 720?

Postby grigorib » Mon Mar 02, 2020 9:05 pm

It won’t fly faster with 450, rather otherwise (450 is as thick as 483 and is more pointed down making setup slower). You might get better speed result flying it with 425 race stabilizer though as it’s thinner.

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Re: Which Stab for the 720?

Postby a99 » Mon Mar 02, 2020 10:36 pm

Can't understand how very different shape wing can be have the same characteristics of slow and fast rides as 683?

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Re: Which Stab for the 720?

Postby grigorib » Mon Mar 02, 2020 10:48 pm

a99 wrote:
Mon Mar 02, 2020 10:36 pm
Can't understand how very different shape wing can be have the same characteristics of slow and fast rides as 683?
It would have same average high speed as 683s because it’s as thick as 683s. 720 doesn’t go as low as 683s because of smaller area but when ridden with large stabilizer like 483 the lowend improves significantly even for smaller wings.
Stall speed of 720 is certainly higher than 683s
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Re: Which Stab for the 720?

Postby Peter_Frank » Tue Mar 03, 2020 8:32 pm

Sorry, I dont understand this, what you are writing here and in other posts about stab wings and speed?

Just calculated an example, having a rear stab around 270 cm2, a front wing 1200 cm2, mast submerged 25 cm only, and comparing the overall drag at high speed (meaning virtually no induced drag - not true, but just to be in favor of you)
Comparing a 6 % stab and a twice as thick 12 % stab, same area, and how much the thicker 12 % would increase overall drag.

4.2 %.

And I doubt the thick/thin stabs are a factor 2 different, besides there will be a tad of induced drag also, meaning the realistic drag difference from a thick to a thin stab will most likely be around 1-2 % overall only.
Higher AR stabs dont really have noticeable less drag, as they ride close to zero lift coefficient.

I doubt freeriders can feel this difference at all, it is more likely a mental thing, it you THINK it is better when thinner and more low drag, it will feel hugely like this :naughty:

Of course in racing it matter more, no doubt :D

8) Peter

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For sale: Slingshot SST 6m 2018 $480, Slingshot Turbine 5m 2017 like new $450, BROkite carbon board 140x44cm like new complete $650, Slingshot Rally 6m 2017 like new $530

Moses 590/647/330 $690, Moses 679/749/483 $890, 80cm alu mast $260
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Re: Which Stab for the 720?

Postby grigorib » Tue Mar 03, 2020 9:19 pm

Peter_Frank wrote:
Tue Mar 03, 2020 8:32 pm
Sorry, I dont understand this, what you are writing here and in other posts about stab wings and speed?

Just calculated an example, having a rear stab around 270 cm2, a front wing 1200 cm2, mast submerged 25 cm only, and comparing the overall drag at high speed (meaning virtually no induced drag - not true, but just to be in favor of you)
Comparing a 6 % stab and a twice as thick 12 % stab, same area, and how much the thicker 12 % would increase overall drag.

4.2 %.

And I doubt the thick/thin stabs are a factor 2 different, besides there will be a tad of induced drag also, meaning the realistic drag difference from a thick to a thin stab will most likely be around 1-2 % overall only.
Higher AR stabs dont really have noticeable less drag, as they ride close to zero lift coefficient.

I doubt freeriders can feel this difference at all, it is more likely a mental thing, it you THINK it is better when thinner and more low drag, it will feel hugely like this :naughty:

Of course in racing it matter more, no doubt :D

8) Peter
I meant two different things:
area - smaller area stabilizer delivers less pitch stability. 450 is larger than 483 (by Moses specs) then go smaller and smaller 425, 420, 325 and 330. The moment you start shimming them you can increase stability by increasing downward push therefore increasing drag
profile thickness - thicker stabilizers 450-483 feel slower, kite stabilizers feel faster (less drag), stabless feels minimal drag.

It's not only I think they're different - I tried 720 with 450 and 325 side by side and I knew difference exactly. 325 felt less draggy but unstable like crap and needed more speed to go.
Similarly I rode 695 wing with 330 vs. 420 stabilizers and even they're equally thick, larger 420 provided better lowend and felt more stable overall. Other two riders felt that race 420 stabilizer compared to usual 330 they ride moved their stance forward by 2" or so. They didn't comment on lowend/speed difference.

My feeling is Moses should not be making 325 and 330 stabilizers - those are not good compared to race versions. Race stabilizer can easily be used with large kitefoiling wings, just as they're meant to be used with winsurf foiling wings. Larger/stronger 450 might still be a good idea for huge 1500+ sq.cm wings but I'm no expert in those


What I can't measure is how much drag is introduced by profile difference combined with pitch of stabilizer. It would have been the simplest to measure that experimentally and I wish hydrofoil manufacturers would subcontract university labs to do that and we'd all benefit from having better wings.


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