Contact   Imprint   Advertising   Guidelines

Comparative measurements of mast flex and torsional stiffnes

A forum dedicated to Hydrofoil riders


User avatar
Starsky
Very Frequent Poster
Posts: 4374
Joined: Mon Apr 19, 2004 12:12 pm
Kiting since: 0
Brand Affiliation: None
Location: Ontario

Re: Comparative measurements of mast flex and torsional stiffnes

Postby Starsky » Thu Aug 17, 2017 9:56 pm

tegirinenashi wrote:
Thu Aug 17, 2017 4:54 am

This is why, designs like zeeko (which features plate without collar) would likely to exhibit poor flex number. And their marketers came with nothing better than filming head on masts collision with their competitor. Really?
Nerd out all you like. Means squat to the majority of freeride foilers. A perfectly rigid foil could still be a complete dog.

The zeeko is quite obviously up to the task and one of the best reviewed non race foils out there, from a company with perhaps the longest track record.

Ill put more stock in that than your tinkering !

I can see comparing these measures on a standardized rig for top end race foils, but for nearly anything else, I'd rather hear what a decent rider has to say about it.

tegirinenashi
Frequent Poster
Posts: 454
Joined: Wed Aug 27, 2014 3:29 am
Kiting since: 2003
Local Beach: 3rd Ave
Gear: Cabrinha CO2 9.5m, Naish x2 14m, Litewave 161
Brand Affiliation: None

Re: Comparative measurements of mast flex and torsional stiffnes

Postby tegirinenashi » Thu Aug 17, 2017 10:09 pm

If you are offended by my Zeeko criticism, I can balance it by pointing out what LF did wrong. Their alum fuselage is a solid chunk of metal and weights a whopping 1.2 kg. As you can see from my numbers, they could have easily went for hollow tube, or thinner profile while loosing some torsion strength in the fuselage without affecting performance too much. This whole LF rig can drop 500 grams easily. Unfortunately, they decided to fix this by making carbon fuselage and charging customers $400 for it. Tough luck: I'd rather buy something else.

BWD
Very Frequent Poster
Posts: 3139
Joined: Thu Jun 05, 2003 3:37 am

Re: Comparative measurements of mast flex and torsional stiffnes

Postby BWD » Thu Aug 17, 2017 11:04 pm

The zeeko plate with no fillet, collar or gusset is a little bit of a headscratcher, considering they take the trouble to CNC their Al fuselage, yet my zeeko seems plenty stiff.
Unless that's the reason I am not an expert after a dozen sessions of foiling :rollgrin:
LF being such a small company just can't afford to CNC anything, right? ;)
Without running any numbers, probably if you go to 13-14mm mast thickness, you need a collar on the plate...
Zeeko also don't use 6061 t-6 but claim to use something stiffer, fwiw.

User avatar
Starsky
Very Frequent Poster
Posts: 4374
Joined: Mon Apr 19, 2004 12:12 pm
Kiting since: 0
Brand Affiliation: None
Location: Ontario

Re: Comparative measurements of mast flex and torsional stiffnes

Postby Starsky » Fri Aug 18, 2017 12:07 am

Offended?! By your opinion of a foil you have never ridden? That's a good one.

Your tecking out comparing mm of flex and torsion between foils that in the real world perform drastically different. What would you conclude had the numbers come out the same? Like so much of your conjecture. It amounts to nothing.

Lets be real. There is likely enough error in your rig to negate your observations. I've seen the stuff you build!

Your efforts are better spent on the water. Learn to foil well, it might help your opinions gain weight.

User avatar
Starsky
Very Frequent Poster
Posts: 4374
Joined: Mon Apr 19, 2004 12:12 pm
Kiting since: 0
Brand Affiliation: None
Location: Ontario

Re: Comparative measurements of mast flex and torsional stiffnes

Postby Starsky » Fri Aug 18, 2017 1:13 am

BWD wrote:
Thu Aug 17, 2017 11:04 pm
The zeeko plate with no fillet, collar or gusset is a little bit of a headscratcher, considering they take the trouble to CNC their Al fuselage, yet my zeeko seems plenty stiff.
Have yet to read of a Zeeko lacking in stiffness at the plate. What makes you think a collar would have any real impact. The only alloy foils I have read about on here having slop at the plate have been LFs .... with collars. If the threads lose their integrity there is going to be play. No collar can stop that. The only way I can see a collar helping out is if you weld the whole thing together.


viewtopic.php?f=196&t=2384727&hilit=shim&start=310

User avatar
Kamikuza
Very Frequent Poster
Posts: 5401
Joined: Fri Jan 09, 2009 4:49 am
Local Beach: Sabae Beach
Favorite Beaches: Ol' Stinky
Gear: This, that, the other

Re: Comparative measurements of mast flex and torsional stiffnes

Postby Kamikuza » Fri Aug 18, 2017 2:39 am

Starsky wrote:
Fri Aug 18, 2017 1:13 am
BWD wrote:
Thu Aug 17, 2017 11:04 pm
The zeeko plate with no fillet, collar or gusset is a little bit of a headscratcher, considering they take the trouble to CNC their Al fuselage, yet my zeeko seems plenty stiff.
Have yet to read of a Zeeko lacking in stiffness at the plate. What makes you think a collar would have any real impact. The only alloy foils I have read about on here having slop at the plate have been LFs .... with collars. If the threads lose their integrity there is going to be play. No collar can stop that. The only way I can see a collar helping out is if you weld the whole thing together.


viewtopic.php?f=196&t=2384727&hilit=shim&start=310
If the bolts weren't seized it wouldn't have been an issue. As it was, the head of the bolt had snapped off so there was no fixing that...

Collar is the same as a gusset or bracing between the plate and the board.

User avatar
Starsky
Very Frequent Poster
Posts: 4374
Joined: Mon Apr 19, 2004 12:12 pm
Kiting since: 0
Brand Affiliation: None
Location: Ontario

Re: Comparative measurements of mast flex and torsional stiffnes

Postby Starsky » Fri Aug 18, 2017 3:05 am

Were OT but the point was, all three units that developed play at the plate did so when the bolts failed in some way, regardless of the collar. Yours was the only one where the bolt actually broke. The other two were seized.


Return to “Hydrofoil”

Who is online

Users browsing this forum: max, meteo and 7 guests