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Wing profile info for backyard hydrofoil builders

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jumptheshark
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Re: Wing profile info for backyard hydrofoil builders

Postby jumptheshark » Fri Apr 23, 2021 12:47 am

Can confirm your chop lift and drop findings. Traversing chop at a more oblique angle helps. If travelling straight down swell there is a particulate speed that you feel it most. Slower and it’s manageable, faster and you barely feel the it. Just right and you trip all day long. Eventually you learn to anticipate well enough.

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Re: Wing profile info for backyard hydrofoil builders

Postby PrfctChaos » Fri Apr 23, 2021 1:45 am

salvatoreone wrote:
Thu Apr 22, 2021 11:49 pm
PrfctChaos wrote:
Mon Apr 12, 2021 1:45 am
Hi All,

In other news, the profile selection tool has gotten another upgrade. 3rd upgrade for those keeping score.
Damn mate, good job! This tool is growing into something powerful! :D :D

I can actually see how the output from the spreadsheet could be used to generate a model in some CAD (like Solidworks or something) with a click of a button. If the model was fully parametric this could be relatively easily done and I probably even have the skills to do that. The only thing you would need to do with it is creating some interface between the wing and fuselage.
ZachMoves wrote: Check out WingHopper.com! A great compliment to this tool. Perhaps we can combine them somehow?
Sort of what this does, it's actually a great tool! It could save many hours of modeling... But I don't see an option to change the foil profile which is basically the whole point of this post :lol:
Thanks mate!

Have a look at the Winghopper thread. Winghopper describes how to import a foilsection into his modelling tool. And will likely do a bit of a colab with Winghopper to make things pretty easy to use, from design to model.

viewtopic.php?f=107&t=2409678&start=10

I'm just busy converting my code to a webapp compatible version at the moment. And if I get the new version to be fast enough, might add a few features while I'm busy.

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Re: Wing profile info for backyard hydrofoil builders

Postby ZachMoves » Sun Apr 25, 2021 12:33 am

salvatoreone wrote:
Thu Apr 22, 2021 11:49 pm
PrfctChaos wrote:
Mon Apr 12, 2021 1:45 am
Hi All,

In other news, the profile selection tool has gotten another upgrade. 3rd upgrade for those keeping score.

1st major version, Aug 2020, included only NACA4 and NACA 5 profiles, around 1000 profiles.
2nd major version, Sep 2020, added basically all the airfoils one can find on Airfoils.com, so up to around 2500 airfoils. Lift induced drag was also added.

Now for the 3rd major version:
In previous versions, the calculation was fairly two dimensional. That means that the average chord length was calculated for the wing and then all lift / drag calculations were based on that single average chord length. So some specific behaviour of the profiles at the extremes of the wing might be missed / ignored (long chord in the middle of the wing and short chord at the wingtips).

The program has now moved to more detailed 2.5d approach. Where the wing is chopped into 10 sections (from middle to the tip), each of these sections are then analysed seperately, before being added together again to find the optimum for the wing as a whole. What it means is:
- The program can now use the correct Reynolds numbers for the bigger chords in the middle of the wing and for the smaller chords nearer the tips. Thus better accuracy. And profile selections where certain parts of the wing would have stalled can be avoided.
- It also means that calculations can accurately be performed for various wing plan shapes. (Typical choices are Elliptical, Tapered or Custom). Induced drag is still only estimated, the required Oswald factor for a given plan shape needs to be entered manually. However, parasitic drag is calculated accurately.
- Wingtip washout can now be calculated accurately (when it comes to parasitic drag). Since each of the 10 sections can be rotated to their respective Angle of attacks for washout.

This does not change the results significantly, but one will notice some small differences. Here is a example with Spirus' wing from the previous page. Comparing Version 2 and Version 3 results.

Version 2:
Capture - Spiru 700 mm x 800.PNG

Version 3:
Capture - Spiru 700 mm x 800Ver3.PNG
Damn mate, good job! This tool is growing into something powerful! :D :D

I can actually see how the output from the spreadsheet could be used to generate a model in some CAD (like Solidworks or something) with a click of a button. If the model was fully parametric this could be relatively easily done and I probably even have the skills to do that. The only thing you would need to do with it is creating some interface between the wing and fuselage.
ZachMoves wrote: Check out WingHopper.com! A great compliment to this tool. Perhaps we can combine them somehow?
Sort of what this does, it's actually a great tool! It could save many hours of modeling... But I don't see an option to change the foil profile which is basically the whole point of this post :lol:
WingHopper does have an option to change the foil profile! You need to make a free account to access that feature. I'm planning on streamlining wing/fuselage interface CAD as well, one of many updates to come :D
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Re: Wing profile info for backyard hydrofoil builders

Postby salvatoreone » Mon Apr 26, 2021 10:54 am

This is amazing, thanks!

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Re: Wing profile info for backyard hydrofoil builders

Postby Damagedd » Wed May 05, 2021 3:34 am

Hi prfctchaos
I will make two foils initially.

First for kite wave, freeride in a 12 to 25 km range.
I guess 750 span and 1350cm.

Second is for wing in a similar speed.
Perhaps 1m span and 1700.

I will also make a faster freeride kite wing 30 to 35km top.

My weight including all gear would be around 98kg.

Im very open to what ever you think.

Cheers

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Re: Wing profile info for backyard hydrofoil builders

Postby PrfctChaos » Thu May 06, 2021 5:02 am

Damagedd wrote:
Wed May 05, 2021 3:34 am
Hi prfctchaos
I will make two foils initially.

First for kite wave, freeride in a 12 to 25 km range.
I guess 750 span and 1350cm.

Second is for wing in a similar speed.
Perhaps 1m span and 1700.

I will also make a faster freeride kite wing 30 to 35km top.

My weight including all gear would be around 98kg.

Im very open to what ever you think.

Cheers
Hi mate,

Might just take a week or so. Just busy with final checks and optimisations for the new version.

Good old Woodies point. Pretty close to my local at Dutchies. Send us a PM if you want to meet at one of the spots sometime and chat foils, might be worth discussing construction plans and your use / background for the foils.

Do you currently foil? What are using at the moment?

Cheers

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Re: Wing profile info for backyard hydrofoil builders

Postby Damagedd » Thu May 06, 2021 2:10 pm

Hi I'm foiling just.
Have almost exclusively been on a surfboard til now.
I made a version of that diy foil on Seabreeze. Finished it back in 2017 but only started using it in last few seabreezes this year.
I'm going to try winging so will be building a board for that and new more modular foil.

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Re: Wing profile info for backyard hydrofoil builders

Postby PrfctChaos » Mon May 10, 2021 7:20 am

Damagedd wrote:
Wed May 05, 2021 3:34 am
Alright, couple of results below for you to have a look at.

750mm wingspan, 1350 cm^2 area, note for this one I have pushed the speed range up to around 17-40 km/hr (10-25 mph), from what I have seen the very-very low speeds (<10 mph) does not really occur when kiting. But happy to run for a lower speed range if you want. The induced drag at the lowest speeds will just become massive for a 750 mm wingspan.
Capture - Damagedd1350.PNG
And having a look at the wider range of wingspans and areas for this speed range, shows that a slightly lower area might also be worth considering. So have added results for a 1080cm^2 option below, to consider. It has a similar lowend, but lower drag around cruising speed of 30 km/hr.
Capture - Damagedd1350 range.PNG
Capture - Damagedd1350 range.PNG (38.23 KiB) Viewed 813 times
750mm wingspan, 1080 cm^2 area, 17-40 km/hr option:
Capture - Damagedd1080.PNG
For the 1m wide wing, I have also pushed the speed range up just a bit to 12-35 km/hr.
1000mm wingspan, 1700cm^2 area, 12-35km/hr:
The combination of wingspan and area looked pretty good. Having a look through changing the surface area didn't show any real additional benefits.
Capture - Damagedd1700.PNG
FYI, this is now version 4 of the software. Same functionality as version 3, it just runs in a different way making it much faster. So can consider a few future detail optimisation options now that it is back to reasonable run speeds.

For example, on the graph there is a value called the "Lift distribution error" it shows how much the lift distribution on the proposed wing deviates from a elliptical lift distribution. In the future this could potentially be used to adjust wing shape and / or Wingtip washout angle to get the lift distribution as close to elliptical as possible over the speed range.
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Re: Wing profile info for backyard hydrofoil builders

Postby Matthijs94 » Mon May 10, 2021 4:42 pm

Hi, I am looking for a set-up that is super stable to practice tricks/transitions for kite foiling. I currently have the Slingshot NF2 with a custom CF pocket board (sometimes taking the alien air board, bigger volume easier touchdown). I weight +-75kg and ride on the north sea, choppy and waves. I have acces to a 3D robot cnc from the automotive industry with super high accuracy. My plan is to build the complete set out of CF, including mast, fuselage, wings and baseplate. Wings should be relatively easy to build compared to the other components. Any advice on the type of wing? Looking for an average speed/liftoff but super stable.

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Re: Wing profile info for backyard hydrofoil builders

Postby Damagedd » Tue May 11, 2021 3:01 am

Great Cheers
I'll build the 1080 first. Will use RichR2 method with VH EPS core, CF uni and double bias E glass.
In the process of making fuselage and though I'd shortcut and buy an aluminium mast. Axis 750x19. Fkn heavy. Will go CF on plywood for the 900.
Thanks heaps will have to catch up.


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