Foil section design using xflr5

[Alan Cattelliot]

This is exactly where my expected operating point for the upwind course begins.

What makes you expect this operating point ? Can't you just increase the upwind area of your daggerboards ? In that case, re-using an existing daggerboard made out of the NACA 0012-34 may be profitable for you, sparing time and perhaps money.

 

[hashtag_laeuft]

Hi Alan,

thanks for your comment and the visual comparision of the two sections.

I actually compared over 30 different sections that visually came into question as potential candidates.
It is very interesting that it finally came down to a NACA 0012 again or in this case the slightly modified GA 30A012 profile, which might be a bit disapointing when reading the title of the thread . As you said - it's the lazy candidate. Without real deep investigations and the aim to re-invent the wheel - or foil - I guess there is no way for a noticeable improvement.

What makes you expect this operating point ?

Actually it's just a bet. Unfortunately, I don't have any real indications for this.
I would like to take a GPS logger with compass on board and record operating data. Speed, course over ground and heading. Preferably with incremental encoders on the rudders or some other gadgetry. Then I could make an accurate statement about how much drift the boat experiences.

In that case, re-using an existing daggerboard made out of the NACA 0012-34 may be profitable for you, sparing time and perhaps money.

Since me and my dad also offer building instructions for this catamaran - Novacat 16 - I don't want to have a one-off solution. I would like to be able to offer our self-builders a good and common solution for the daggerboards as well. Either to build themselves or provided by me.

Best
Nicolas

 

[Erwan]

AFAIR, the Ventilo 20, used to have a NACA 64A10 wing section for her high aspect ratio dagger board, probably with good reasons.
Cheers

 

[wet feet]

Actually it's just a bet. Unfortunately, I don't have any real indications for this.
I would like to take a GPS logger with compass on board and record operating data. Speed, course over ground and heading. Preferably with incremental encoders on the rudders or some other gadgetry. Then I could make an accurate statement about how much drift the boat experiences.


Since me and my dad also offer building instructions for this catamaran - Novacat 16 - I don't want to have a one-off solution. I would like to be able to offer our self-builders a good and common solution for the daggerboards as well. Either to build themselves or provided by me.

Best
Nicolas

It may not be applicable but a couple of years ago I was sailing with a friend who had his Iphone in a waterproof case and it was running some kind of tracking apps.Something suitable may already be out there for your requirements.As we returned to the harbour he was reading off distance travelled and peak speed from his Apple watch.Obviously an Apple fan....

Your mention of supplying design or even complete daggerboards leads to the question of how likely a homebuilder is to achieve really good accuracy and other than enormous patience,there is no easy way.

 

[Erwan]

Nicolas,
For good accuracy, it is probably a good idea to get in touch with R/C F3B Gliders groups
And as Germans used to be and still are probably, the best in these series, I think it could be easy for you to gather good informations to achieve good accuracy for the plug and for the mould, in addition there chords in mm are quite similar to dagger boards chords seen in beach cats.
Unfortunately all these great tips and tricks are usually available in German language only, on dedicated forums.
Cheers

 

[Erwan]

Re-reading former page, I realized you already mentioned 3D printing for the plug.
I never imagined one could achieve a great finish with this technology, but I know very little about 3D printing.
So, please do not hesitate to share your experience with this approach, I am very interested to learn about that, and probably not the only one.
Cheers