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Nak
Since 19 May 2005
4238 Posts
Camas
Site Lackey
CGKA Member
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Wed Feb 06, 19 10:25 pm Improving the Ghost Whisper/Moses 633 |
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I love this foil, but I had three issues with it. First, I hate the dagger shape of the stabilizer. The thought of falling on it does not make me smile. Second, I hate how sharp the edges are. Third, I get a yaw "shimmy" now and then. Other than that, I love this foil. So, I fixed those issues.
The second one was easiest. I sanded off all of the sharp edges. I could see under 18x power magnification exactly where the wing and mast had been sharpened. I sanded that off and rounded the corners a bit. I ended up with a 1mm thick blunt edge. Absolutely no singing whatsoever after the sanding. I can not perceive any difference in handling or performance at all, and the foil is a lot safer now.
Issues 1 is the stabilizer and item 3 is caused by the stabilizer. So I had to find a better stabilizer. After a bunch of research I settled on trying the Slingshot Hoverglide 42cm stabilizer. https://www.slingshotsports.com/Hover-Glide-Rear-Wing-Stabilizer-42cm This stabilizer ended up being near perfect! the chord is identical, the surface area is almost identical, the camber looks damn close and it comes close to bolting right up. I had to extend the rear hole a bit so that the mounting holes would line up. Then I cut down a hoverglide rear shim. https://www.slingshotsports.com/Hover-Glide-rear-wing-shim-kite-windsurf The shim fits perfectly in the stabilizers notch because it was designed to. That, and the flat surface of the shim lines up the angle of attack perfectly as far as I could see. With this mount the stabilizer sits about 3/8" aft of stock.
Anyways, the stabilizer planform--or outline--is nice and rounded and way safer looking the the stock dagger. Also, the wing tips curve up, so I was hoping to cure the yaw instability as well. Mission accomplished!
The rig seems to ride identically to the stock setup as far as I can perceive. The only difference being that the yaw shimmy is gone. The foil still turns on a dime and seems even more stable. Center of lift is unaffected as far as I can tell. Perfect. I was afraid the Frankenstein mounting would sing like a bird, but the rig is still completely silent.
I'm going to make a jig to hold the stabilizer level so that I can drill new mounting holes with a drill press. Once the jig is done I'll fill the holes with a bit of fiberglass and epoxy, drill and paint. it should look pretty nice after that. This will all be purely cosmetic because I have no complaints about function now.
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Mark
Since 20 Jun 2005
3678 Posts
I need my fix because I'm a
Naishaholic
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Thu Feb 07, 19 8:24 am |
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Rides great! Nice job Mike.
_________________ Cleverly disguised as an adult...
www.naishkites.com |
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apctjb
Since 19 Aug 2007
432 Posts
Obsessed
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Thu Feb 07, 19 8:52 am |
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Great ideas and initiative.
Could you provide more detail regarding the specific edges and methods you used to round the edges?
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ldhr
Since 21 Jul 2009
1487 Posts
Hood River
XTreme Poster
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Thu Feb 07, 19 12:01 pm |
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Very interesting - I have also noticed the shimmy - I had the foil resurfaced by Will Cyr and hoping that eliminates the random vibrations that come and go in an instant.
They don't bother me so much and only occur when I'm pushing hard upwind at speed.
Mike - I'm sure you know this - you're a smart guy -but it looks like you're working with pressure treated lumber - hoping you take precautions and don't touch it with bare hands..... unless it's some type of environmentally friendly treatment.
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Nak
Since 19 May 2005
4238 Posts
Camas
Site Lackey
CGKA Member
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Fri Feb 08, 19 2:43 am |
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apctjb wrote: | Great ideas and initiative.
Could you provide more detail regarding the specific edges and methods you used to round the edges? |
I used a sanding block and started with 400 wet sandpaper. I took the trailing edge back to a squared off edge 1mm thick. That's the thickness of the trailing edge where they sharpened it, so I simply eliminated the portion they sharpened. That removed about 1mm from the trailing edge. It's a lot easier to do this if you have some sort of powerful magnification to see what you need to do and judge your progress. I used 18x glasses.
You want to use a hard sanding block so that the edge is nice and square. A rounded edge is more likely to sing than a square edge. I don't know if a rounded edge on this foil would or would not sing, but it might. I just rounded of the corners a little bit till they felt not so dangerous to me...After all that I used 800 wet to take the edge off the squared trailing edges. I didn't round them, just took the edge off the right angles.
BTW, I fell across the foil in Baja and got a rash burn on my leg. I'm pretty sure I would have needed stitches if the wing had been sharp still... The rash disappeared by the next day.
Last edited by Nak on Fri Feb 08, 19 2:55 am; edited 2 times in total |
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Nak
Since 19 May 2005
4238 Posts
Camas
Site Lackey
CGKA Member
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Fri Feb 08, 19 2:51 am |
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ldhr wrote: | Very interesting - I have also noticed the shimmy - I had the foil resurfaced by Will Cyr and hoping that eliminates the random vibrations that come and go in an instant.
They don't bother me so much and only occur when I'm pushing hard upwind at speed.
Mike - I'm sure you know this - you're a smart guy -but it looks like you're working with pressure treated lumber - hoping you take precautions and don't touch it with bare hands..... unless it's some type of environmentally friendly treatment. |
Yeah, I got the shimmy fairly often. After changing the stab not one shimmy or weird vibration in 5 days of riding. The shimmy never seemed to actually affect anything, but I do have a higher level of confidence with the shimmy gone. It's just feels like a more refined ride. Plus that dagger just looks to me like it's waiting to gut someone...
Thanks for the concern! Yep, gloves when handling that stuff and a respirator when working it.
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wylieflyote
Since 30 Jun 2006
1646 Posts
Puget Sound & Wa. Coast
XTreme Poster
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Fri Feb 08, 19 7:39 am |
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Shimmy...
Interesting. I spent all of 2018 on a 590 that I placed a 483 stabilizer with, and I had this anomaly too. Riding along and everything is so perfect, then BOOM the craft goes insane for a millisecond. Is this the "shimmy"? Once called a "sonic boom" on the old LF mast/fish/etc?
Now I'm on the 633/483/91 and a 37 KS.... need more eval time.
_________________ CGKA Member
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Kip Wylie |
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McLovin
Since 11 Sep 2017
284 Posts
Corbett
Obsessed
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Fri Feb 08, 19 11:13 am Beta Tester |
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NAK & Mark,
Thanks so much for continuing to product test all the new toys...can't tell you enough how much I appreciate getting to learn now with so many of the bugs worked out by you guys and many others over the last 20 years...
Sounds like you found a good improvement.
PS - too funny running into you two in that refreshing hot tub at the Palmas de Cortez
KEEP fixing everything - BIG UPS from us new kids still on the TT's
Cheers,
Mc
_________________ 42, the Answer to the Ultimate Question of Life, the Universe and Everything |
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Mark
Since 20 Jun 2005
3678 Posts
I need my fix because I'm a
Naishaholic
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Fri Feb 08, 19 4:55 pm Re: Beta Tester |
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McLovin wrote: | NAK & Mark,
Thanks so much for continuing to product test all the new toys...can't tell you enough how much I appreciate getting to learn now with so many of the bugs worked out by you guys and many others over the last 20 years...
Sounds like you found a good improvement.
PS - too funny running into you two in that refreshing hot tub at the Palmas de Cortez
KEEP fixing everything - BIG UPS from us new kids still on the TT's
Cheers,
Mc
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Very fun hanging with you... and thanks for the recognition! Hope to see you on the water.
_________________ Cleverly disguised as an adult...
www.naishkites.com |
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fisherman
Since 06 Aug 2007
113 Posts
Stoked
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Sat Feb 09, 19 8:21 pm |
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You buy a Stringy and you don't have to do anything. Perfect product. On the top of it, you may learn foiling and that's a bonus !
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fisherman
Since 06 Aug 2007
113 Posts
Stoked
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Sat Feb 09, 19 8:23 pm |
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By the way, working with pressure treated lumber is a life threatening mistake. You may lose a limb. Ask any framer who has been working with it for decades.
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Nak
Since 19 May 2005
4238 Posts
Camas
Site Lackey
CGKA Member
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Sun Feb 10, 19 12:10 pm |
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wylieflyote wrote: | Shimmy...
Interesting. I spent all of 2018 on a 590 that I placed a 483 stabilizer with, and I had this anomaly too. Riding along and everything is so perfect, then BOOM the craft goes insane for a millisecond. Is this the "shimmy"? Once called a "sonic boom" on the old LF mast/fish/etc?
Now I'm on the 633/483/91 and a 37 KS.... need more eval time. |
The shimmy I got was the foil would yaw back and forth quickly for a second or two. It doesn't seem to actually affect anything, just a bit disconcerting. The ride is smoother and more refined with the Slingshot 42cm stab. Still quick and easy to turn, just no shimmy.
McLovin wrote: | NAK & Mark,
Thanks so much for continuing to product test all the new toys...can't tell you enough how much I appreciate getting to learn now with so many of the bugs worked out by you guys and many others over the last 20 years...
Sounds like you found a good improvement.
PS - too funny running into you two in that refreshing hot tub at the Palmas de Cortez
KEEP fixing everything - BIG UPS from us new kids still on the TT's
Cheers,
Mc
| Thanks Mc! Good meeting you in Baja!!
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Nak
Since 19 May 2005
4238 Posts
Camas
Site Lackey
CGKA Member
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Tue Mar 05, 19 12:03 pm |
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Here's how it ended up looking. I've got most of the original finish sanded off What's left looks a bit splotchy, but should look better after clear coating. Regardless, it rides great; it has a more refined ride than stock. Still "twitchy" in that it really wants to turn. The shimmy is completely gone however. There might be just a tad less front foot pressure required, but I'm not completely sure on that. Basically, the only noticeable difference is that the shimmy is gone. I'm most happy that the dagger stabilizer is gone! I REALLY did not want to fall on to that thing!
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skideeppow
Since 26 Aug 2011
519 Posts
Addicted
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Mon Mar 11, 19 9:13 am |
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my stabilizer i received from Slingshot looks totally different. I will take a pick and send it over.
I also love the 633, game changer for me. Foot trans are easy and the foil is super fun to ride.
I dont know that i would want to sand mine, would be super nervous on fucking it up. any tips, or video on how to do it?
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wylieflyote
Since 30 Jun 2006
1646 Posts
Puget Sound & Wa. Coast
XTreme Poster
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ldhr
Since 21 Jul 2009
1487 Posts
Hood River
XTreme Poster
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Mon Mar 11, 19 11:52 am |
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The wings are underwater - Can you really hear a whisper if it initiates from the wings underwater?
I always assumed any type of whistle initiated from the mast above the water.
BTW - my Slingshot hoverglide and 633 have never made any whistling sounds.
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Nak
Since 19 May 2005
4238 Posts
Camas
Site Lackey
CGKA Member
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Tue Mar 12, 19 11:41 pm |
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ldhr wrote: | The wings are underwater - Can you really hear a whisper if it initiates from the wings underwater?
I always assumed any type of whistle initiated from the mast above the water.
BTW - my Slingshot hoverglide and 633 have never made any whistling sounds. |
The primary source of whistling is the trailing edge of the wings and/or mast. Some are so loud you can hear them from the beach... Seriously. Neither my 633 or my LP foils have ever made any noise as well.
skideeppow wrote: | my stabilizer i received from Slingshot looks totally different. I will take a pick and send it over. |
The photos in my last post show the Hoverglide 42cm stabilizer after I sanded off the finish.
Good technique in the video showing the trailing edge sanding. The sanding block is important to get a square trailing edge. A rounded trailing edge is way more likely to sing. I'm not saying it will, it depends on the shape of the whole wing. But rounded is more likely to sing. That said, after squaring off the trailing edge to 1mm, I used 400 grit sandpaper held without a block to relieve the squared edges slightly, not enough to round the edge, but enough to take the edges off. No singing at all; still quiet.
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