Mast profile experiences?

[tahoedirk]

Please share any experiences with altering your mast/keel/strut profile.

Lately , as I ride through inconsistent wind or current, I have had problems exploding for no obvious reason, especially when pressuring excessively. Also at high speed I am seriously at risk of blowing up. I call it sucking a bubble

I have been trying to scrutinize the top performing masts and there are no apparent consistent characteristics. The sword 2 is impressive and seems to have a thin flat trailing edge about 1/2 " wide down the whole length. Their foils thin out significantly also. Spotz does not thin out nearly so much , but it is lightning fast and seems to get even more stable at high speed. The others I have looked at carefully also do not seem to have the wide point too forward in the chord and do not seem excessively thin in the trailing edge.

Has anyone been experimenting with fine tuning their mast profile? Would you care to share your results?

[Denisesewa]

I had similar issues with mast ventilation as can be seen in this thread viewtopic.php?f=196&t=2389015, the worst occurs at 105 and near the end of the vid. I made my 3 foils with very blunt leading and trailing edges ( for safety while learning) with the thick part of the profile about %30 back from the leading edge, mast thickness on one ( the thickest one) is 17mm and chord is 105mm, I then altered it by extending the chord to 120mm and moving the high point back to around %40 as well as defining the profile with a sharper leading edge, more defined high point and some concave near the trailing edge, all this was to increase the thickness to chord ratio and provide an cleaner entry and exit with less chance of laminar flow separation, I also thinned out the wings and defined their profile.
Testing is all positive, the foil is much faster, absolutely silent and not a single incidence of ventilation, Changing the wing profile changed the center of lift and my foot position quite a bit, the wider chord does not noticeably change turning characteristics.
On the left is a 2014 MHL lift profile, the middle is my original mast section and the right is a liquid force ( the manta mast is similar to liquid force but thinner) all of which I shortened for shallow water, the other pics are of my original and modified mast, you can see how blunt the original was and how undefined the high point was.

[tahoedirk]

Thanks Denise,
This one is my third effort also , sharp enough LE, 16 mm widest point, fairly thin trailing edge slightly concave , 100mm however. I was thinking 14x 120 more concave and parallel TE would work better. Overall I'm quite happy with what I have , I just want to keep improving.

I just saw some new flat racing foils cut with a CNC out of G10 performing amazingly.

I guess it is all good

[bigcane]

Thanks Denisesewa, that is great info. With my homebuild I also have ventilation issues on one tack and also alot of noise from the TE so I'll see if adding more carbon and then sanding the TE sharp will solve the problem.

[Scuba]

Hi interesting topic, i was going to build another mast and fuse, i was thinking of 12mm thick with a chord of about 120mm.
Not sure on the eppler shape but looking at putting some concave in the trailing edge.
What would be the ideal dims for your mast?
Thanks