Contact   Imprint   Advertising   Guidelines

Best way to make a prototype

Forum for hydrofoil builders.


plummet
Very Frequent Poster
Posts: 5934
Joined: Sat Aug 29, 2009 11:25 pm
Kiting since: 33
Local Beach: EE
Favorite Beaches: NZ
Style: Terrain riding
Gear: Old wornout ozone.
Plummet hydrofoil and mutant
Brand Affiliation: None

Re: Best way to make a prototype

Postby plummet » Thu May 31, 2018 8:47 am

downunder wrote:
Thu May 31, 2018 7:22 am
"* Rear wing on the top fuse. That means the bolts don't take all the load. "

- which load? The stab bolts are definitely not taking the longitudinal load but a side one.

* Ensure an easily adjustable rear wing aoa.

- umm why? Without knowing the front wing specs it can be even near 0 degrees...

* 8mm hardware is robust.

- 6mm is not near enough.

* Rear stable about 2/3 surface area as front wing.

- Umm, Levitaz is not 2/3, or any race by that matter.

* Fuse could be a bit long.

- that's why there might be more holes to move a wing...

C'mon Plummet, you riding a DIY board, I recon all knowledge you've got is from reading and not seeing it in person?

Anyways, not to bash you, just pointing to leave to more Authoritative guys on the topic to answer. Which I'm not. But nice try tho...

I think you do mean to bash me. You aim to discredit my input. My knowledge is based on my research and the fact that I have successfully designed and built, learned on and refined my own hydrofoil that works very well. I have been riding it for 18 months and have a number of lessons learned which I would like to share.

Here is the link to my build if you are interested.
viewtopic.php?f=199&t=2394150&p=1000544 ... d#p1000544

I know you have been working on a hydrofoil. Have you completed it yet? ridden it yet? post details on your progress. Are you up and riding yet?
PS my day job is mechanical engineering design, prototype and manufacture..... So I know a thing or 2 about prototyping,

None the less i'll answer your questions.

"* Rear wing on the top fuse. That means the bolts don't take all the load. "
- which load? The stab bolts are definitely not taking the longitudinal load but a side one.

As you know the rear stab wing profile is flipped compared to the front wing. It is designed for negative lift (correct term?). Stab on the top of the fuse means the stab is getting pushed into the fuse. The bolts need to locate the stab, But the most of the lifting force of the stabstab is taken by the fuse. Put the rear stab on the bottom of the fuse and the bolt need to take all the lifting force of the stab as the stab is trying to tear away from the fuse. If the bolts start to loosen the lifting force of the stab can potentially loosen the stab faster. I have seen a bottom mounted stab on a production foil with loose bolts. When you consider design you want to limit failure. This is one small way of doing that. Another advantage of the rear stab on the top is that it is less likely to be damaged with ground strikes.
PSS The opposite is true on the front wing of course. Front wing on the bottom is best.

* Ensure an easily adjustable rear wing aoa.
- umm why? Without knowing the front wing specs it can be even near 0 degrees...
When you first design a foil the optimal AOA of the stab is unknown. Sure you can go with industry accepted settings. However the tune the foil for optimal performance you want to be able to easily adjust the rear stab aoa. Also as your riding progresses you will find you may like a looser feel. The ability to adjust the stab gives you easy tuning as you progress. Lastly, for the prototype you most definately wany adjustability to get the ultimate tune. Once happy with that setting you may choose to lock that in for the production run. Personally I like the adjustability feature.
PSS typical AOA of rear stab sits between 1-3 Deg

George at Delta hydrofoil explains it better than.
phpBB [video]



* 8mm hardware is robust.
- 6mm is not near enough.
I agree. Many production foils use 6mm and sometimes smaller!....

* Rear stable about 2/3 surface area as front wing.
- Umm, Levitaz is not 2/3, or any race by that matter.
Its a good rule of thumb. As you increase stab size you increase stability and drag. Less stab less stability, less drag.
The longer the fuse the smaller the stab can be in relation to the front wing. So when looking at stab size the fuse fuse length must be considered as does the intended purpose of the foil.

* Fuse could be a bit long.
- that's why there might be more holes to move a wing...
Fair enough. Additional holes will increase drag. I's suggest to test fuse length then lock it in for production.

User avatar
downunder
Very Frequent Poster
Posts: 1428
Joined: Mon Jul 01, 2013 7:16 am
Kiting since: 1970
Gear: building my own
Brand Affiliation: None
Location: Perth, Australia

Re: Best way to make a prototype

Postby downunder » Thu May 31, 2018 9:29 am

^

C'mon Plummet, how can you share your experience when riding only a DIY foil? Please be true to yourself and us, you've never ridden anything else (apologies if you were, but even if true, for how many hours?).

Sure I do, I have also a carbon Chinese one, so what. I'm not an expert in a field tho by claiming that if I've built one, refined it etc I am the God given expert. Im tired of your Mutant as well. Now I'll read about your foil for the next 5 years, and how well it works (again you attached your link as a Holly Grail of DIY - not interested btw, it's ugly as hell, only ppl who never built anything will praise it politely, sorry, my attitude is to say how it is, not wrapping it much).


How do you know who am I and what do I do?


I am questioning your research which is purely based on reading. And it is not discrediting, but a critical thinking. If you taking it as discrediting this is your problem, not mine.

As said more times that I can remember, you are placing yourself as an Absolute authority on EVERYTHING. Even on a SB. You're building your profile in that manner, thankfully some on a SB recognized that, so now you're taking it more in here where ppl might tolerate. Now, that's bashing if you like. I'm sure you are a nice guy, but glad do not live in your area coz man I could not team up with you.


~~~

* 8mm hardware is robust.
- 6mm is not near enough.
I agree. Many production foils use 6mm and sometimes smaller!....

- right, how many masts did you see broken on your local? Not one? Me? Quite a few with 6mm bolts.

* Rear stable about 2/3 surface area as front wing.
- Umm, Levitaz is not 2/3, or any race by that matter.
Its a good rule of thumb. As you increase stab size you increase stability and drag. Less stab less stability, less drag.

- bla bla bla, you know well when prototyping you NEED to have more options to move the stuff around. Drag when prototyping? C'mon...Fill the hole = no drag.

* Fuse could be a bit long.
- that's why there might be more holes to move a wing...
Fair enough. Additional holes will increase drag.

- Again you about the drag, and than agreeing that for prod 'lock it in'. That's the whole purpose of prototyping, have u seen a kite and the number of attachment points when prototyping?

plummet
Very Frequent Poster
Posts: 5934
Joined: Sat Aug 29, 2009 11:25 pm
Kiting since: 33
Local Beach: EE
Favorite Beaches: NZ
Style: Terrain riding
Gear: Old wornout ozone.
Plummet hydrofoil and mutant
Brand Affiliation: None

Re: Best way to make a prototype

Postby plummet » Thu May 31, 2018 1:04 pm

I never claimed to be an expert. I have experience in this area and I shared it. Which is what forums are for. It gives OP some options to consider. He can use the advice or disregard it.
You are allowed to disagree of course. That is also what forums are for. Stick to the facts. If you don't agree with my advice then counter it with your own understanding and facts proving evidence otherwise.

However personal attacks are not cool. You don't have to agree or like me. But please keep things civil. How is posting degrading comments helping OP's request?
I think you need to look inward at yourself and consider why you are getting annoyed. Someone on the internet posted something you don't agree with.

Does it really matter at all?

This is my last response to you Downunder. I won't read your posts or respond to your abuse anymore. I suggest you put me on your ignore list. Then you won't need to read my posts and get annoyed at them. Go out and have some fun. Blow off some steam and forget about the people on the internet you don't agree with.


Kitemanmuc if you find my advice useful we can continue to share ideas. If not say so ill back away from the thread.

tahoedirk
Frequent Poster
Posts: 211
Joined: Sun Aug 31, 2014 5:02 pm
Kiting since: 2001
Local Beach: Kings beach, CA
Favorite Beaches: All clean beaches
Style: out of control
Gear: Homemade gear
Brand Affiliation: None

Re: Best way to make a prototype

Postby tahoedirk » Thu May 31, 2018 6:19 pm

If you are riding your own homebuilt hydrofoil you are probably an expert!
I don't agree with all your points Plum , but someone asked for your input. Good job throwing it out there, all legit if you ask me!

stab on the bottom for huge jumps? sure . 1/3 , 2/3 isn't as important as aoa or the stab itself

I'm hesitant to even share anymore, it's barely worth it with all the arm internet chair scholars with calipers and angle apps.

This is truly a refined craft , Cheers to all for trying!

go for it any way you can . I'll ride it

revhed
Very Frequent Poster
Posts: 1119
Joined: Sun Feb 24, 2008 6:15 pm
Kiting since: 1987
Local Beach: france
Gear: kites
Location: France

Re: Best way to make a prototype

Postby revhed » Sat Jun 02, 2018 9:20 am

tahoedirk wrote:
Thu May 31, 2018 6:19 pm
If you are riding your own homebuilt hydrofoil you are probably an expert!
size related to F wing isn't as important as aoa or the stab itself
This is truly a refined craft
Just a few thoughts.
In the learning stage if you are lucky enough to have a confirmed KBHF pilot who can test your DIY
and tell you if it works well enough or not is a huge plus!
I am quite sure many guys have tried to build and failed, breakage, bad design, poor choice of materials, ect
Funny paradox is that because you do not know how it should fly because you are learning you will not know if it is
ok, where as a experienced rider will be able to ride almost anything within reason.
it is just hard to build a STRUT that is thin enough for performance but is stiff in both length and twist.
Adjusting relative wing AoA again not knowing can also daunting.
With some brand new prices coming down and used gear becoming more and more available DIY should be
well thought out.
Is it fun to fly something you designed and built, for sure.
Is a factory able to build better because of machines not available to most DIY guys, YES!
As one gets better pushing low wind limits , going faster, and simply looking for that ultra streamlined cutting thru
the water feeing can be VERY difficult for most DIYers.
And in closing,
the materials needed for most quality builds are toxic, itchy, and otherwise just not user friendly to ones health.
Although I am not a fan at all of alu, seems that if one takes care it can be an option for STRUTS and fuses making building much easier.
Boards are easy, the 2 STRUT connections need care.
R H

plummet
Very Frequent Poster
Posts: 5934
Joined: Sat Aug 29, 2009 11:25 pm
Kiting since: 33
Local Beach: EE
Favorite Beaches: NZ
Style: Terrain riding
Gear: Old wornout ozone.
Plummet hydrofoil and mutant
Brand Affiliation: None

Re: Best way to make a prototype

Postby plummet » Sat Jun 02, 2018 9:39 pm

revhed wrote:
Sat Jun 02, 2018 9:20 am
tahoedirk wrote:
Thu May 31, 2018 6:19 pm
If you are riding your own homebuilt hydrofoil you are probably an expert!
size related to F wing isn't as important as aoa or the stab itself
This is truly a refined craft
Just a few thoughts.
In the learning stage if you are lucky enough to have a confirmed KBHF pilot who can test your DIY
and tell you if it works well enough or not is a huge plus!
I am quite sure many guys have tried to build and failed, breakage, bad design, poor choice of materials, ect
Funny paradox is that because you do not know how it should fly because you are learning you will not know if it is
ok, where as a experienced rider will be able to ride almost anything within reason.
it is just hard to build a STRUT that is thin enough for performance but is stiff in both length and twist.
Adjusting relative wing AoA again not knowing can also daunting.
With some brand new prices coming down and used gear becoming more and more available DIY should be
well thought out.
Is it fun to fly something you designed and built, for sure.
Is a factory able to build better because of machines not available to most DIY guys, YES!
As one gets better pushing low wind limits , going faster, and simply looking for that ultra streamlined cutting thru
the water feeing can be VERY difficult for most DIYers.
And in closing,
the materials needed for most quality builds are toxic, itchy, and otherwise just not user friendly to ones health.
Although I am not a fan at all of alu, seems that if one takes care it can be an option for STRUTS and fuses making building much easier.
Boards are easy, the 2 STRUT connections need care.
R H
All very true statements. I had not ridden a foil before building one. Whats more I had only physically seen one in the flesh, there was no one at my local foiling. I had nobody who could test my design once made. So I had zero reference point on what was good bad or ugly before i started researching and designing.

None the less, there's a lot of info out there and some really knowledgeable guys on here willing to share info. So it is not impossible to design, build, learn, ride your own home build.


I would suggest buying a cheap foil second-hand foil, learning on it and while learning formulate design the design based on what you like/ don't like about the one you currently ride. Then once your foil is built you will bypass a whole lot of potentially bad set up and frustration.

Here's my set up journey.

First I had the foil too far forward on the board. I would just rocket ship out of the water. The foil was unridable. But i didnt know if it was set up or bad design or just the learning curve!

After a few rocket shipping sessions I adjusted the foil position and stopped the rocket ship.

Cool I started to foil. But the foil was really twitchy and sensative. At the time i didnt know it spent the first month of learning with a Stab aoa that was too shallow. It made for lots of crashes due to a hyper sensative board. Again i didnt know what it should feel like. I adjusted the Stab aoa which totlally changed the feel of the foil. It became stable and easily ridable by comparison.


So i continue to learn for several months more with a high stab aoa. I'm foiling around easily now but still finding it hard to control high speed. I set the aoa back a bit shallower. That makes high speed better to control and make the foil a bit more lively and less stable. It's a setting I like.


Months go by and Bletti (kite forum member) roles into town and we do a foil swap. I get to ride my first production foil! It was a spitfire! So a backward canard foil. Anyway after 10-15 mins if crashing getting used to the spitfire I am able to blast around on it and draw some conclusions. My foil is actually faster, better upwind and more stable. I'm pretty pleased about that! I preferred my foil to the spitfire!

The spitfire was dead silent, more maneuverable and better at slow speed. Anyway, Bletti informs me that the foil rides fine but the back foot position is too far forward leading too much rear foot pressure and leg burn. I take his advice and reposition the foil, keeping that front foot position the same and moving the foil back and boom! awesome foil. No more rear leg burn, better at controlling speed and more maneuverable.

It took me about 6-7 months to go from incorrect set up to correct set up for my liking.

rtz
Very Frequent Poster
Posts: 537
Joined: Mon Jan 24, 2011 6:47 am
Kiting since: 2010
Favorite Beaches: OBX
SPI
Style: Freeride
Gear: SlingShot, Switch.
Brand Affiliation: None

Re: Best way to make a prototype

Postby rtz » Thu Jun 07, 2018 7:56 am


User avatar
NYKiter
Very Frequent Poster
Posts: 1726
Joined: Fri Mar 22, 2013 9:17 pm
Kiting since: 2010
Style: Wave
Gear: .

Re: Best way to make a prototype

Postby NYKiter » Tue Jun 12, 2018 2:24 am

Can you tell us what you learned from the computer...did it tell you how to balance the wing sizes for stability?
Did it tell you where to put the mast for optimal balance?
Anything that you can share form the experience?

User avatar
downunder
Very Frequent Poster
Posts: 1428
Joined: Mon Jul 01, 2013 7:16 am
Kiting since: 1970
Gear: building my own
Brand Affiliation: None
Location: Perth, Australia

Re: Best way to make a prototype

Postby downunder » Tue Jun 12, 2018 7:56 am

Plummet

that's funny, I should be civil and you've got 6000 posts here, plus 4000 on other forums. Which makes you what exactly?

Sorry, I've made a mistake opening your post, I've thought maybe something changed and the World is not spinning around your stories...

atomic-chomik
Medium Poster
Posts: 166
Joined: Sat Jul 05, 2014 10:33 pm
Kiting since: 4
Local Beach: The wild west
Style: Freeride/Surf
Gear: North Dice 8 and 10m
North Neo 12m
OR Prodigy 7m
OR Prodigy 9.5.
OR Prodigy 12m
2014 Rebel 5m and 8m
OR 17M Flite
OR Duke
Cabrinha Phenom 5'8
Brand Affiliation: None

Re: Best way to make a prototype

Postby atomic-chomik » Wed Jun 13, 2018 5:21 am

Plummet, I have now built a few foils, starting with crapola and now having a couple pretty nice setups. I found your explanation and lessons learned quite accurate and also validated a few things i have been trying(one being multiple holes for stab placement and size relation to that placement). Thanks for sharing that man.


Return to “Hydrofoil Builders”

Who is online

Users browsing this forum: No registered users and 4 guests