I have been using the Severne Foilglide 2 in 7 and 8 with a 460 RDM for a while. I appreciate their light weight, low end power and superb camber rotation, but feel they lose a bit of stability and increasing backhand pull in the gusts (compared to for example Overdrives).
Has anyone tested SDM vs RDM on the Foilglides, or can anyone make a qualified guess on potential stability improvements? And if so, what is sacrified?
My sailing is more in the Freerace rather than Freeride category, using Patrik F-ride 145/ SB GT-R.
I think stability comes from wide luff of the race sails, so SDM will not give the magic you are looking for, at best, minor change with rotation getting dramatic down grade
Great foil freeride sail with lightweight construction that keeps customers buying regularly, best purchased new
Funny (and correct) that we now talk about the race sail wide luff sleeve contributing to lower drag and cleaner aero. Back in the formula days the sail manufacturers talked about the wide sleeve being for easier rigging, and they never mentioned the aero advantage. Check out some of the old Maui Sails videos. It was all about rigging. I kept looking for Phil to say something about aero, but he never did.
To me as a retired Boeing scientist, the aero advantage is obvious. Heck, the AC sails have taken this wide luff thing to the extreme and have sails with two surfaces. Now THAT'S an aero advantage. People experimented with this for windsurfing, but they were too heavy.
Big fan of FoilGlide 7.0 - have both V1 and V2 (!)
Originally used RDM, but at 95+ kg I have never liked RDMs in slalom sails etc
Much preferred feel/stability of SDM in 7.0 V1, cam switch is simple
Now use SLAKE MDMs for all my foil and slalom sails over 6.0 - best of all worlds, gives fantastic range in the FG 7.0
Segler, you only need to remember Aeroforce and some Freedoms to know the aero advantages were beaten to submission.....verbally and in ads, by 1986.
When they reappeared 17 years later, they did talk about aero AND easier rigging.
Hype is only important if it proves advantages in the water.
From other threads it seems like the common theory is that SDM masts flex faster and RDMs have a softer feel and 'breaths off' gust power supposedly benefitting lightweights (I'm 75 kg myself). But I wonder if this is more important on a fin than on the foil (due to lower resistance with foiling).
So the question is maybe if this 'breathing' or other RDM charasteristics impacts the sail profile and thereby increase backhand pull in the gusts more than a SDM setup. Or if it is negligible compared to other parameters mentioned in this thread (cams, battens, luff sleeve, etc). Hopefully I will be able to do a test in the coming week or so.
I have to wonder whether the performance gap between SDM and RDM is narrowing. My newer Flyer 7.0 (5-batten) is supposed to rig on a RDM 430. It was not good. Way too noodly and too hard to handle on the water. Sailworks recommended I try a RDM 460. I borrowed one. It was not any better. However, then I got the NoLimitz FAST 460 cm 95% RDM Mast. Holy cow, what a difference that made. The sail was quiet in gusty winds. Steady power to make for an easy ride.
So I got the opportunity to test a Apex 460 SDM mast with the FG2 8.0. Overall it works well, although only a marginal (if any) improvement in stability. Slightly worse cam rotation, so I will stay with the Severne RDM Red mast, and just accept it's not a race sail.
On another note I find the gap between the FG2 8 and 7 to be way too small, but the gap between FG2 8 and Overdrive 7 to be perfect. The stability of the Overdrive is better for high wind foiling, and when the wind really hits I just change the foil board for a 100 liter slalom board. And that is my two sail, two board combo that covers 90% of my sailing time.
This is probably the most relevant thread as I recently picked up a 6.0 foil glide to give me something a bit more smaller and still cammed for when it's really going. This was after running the 725 front wing with my 7.0 foil glide and finding it really nice on an 95cm board. Way less stressful and more fun than sticking with a 9.0 HGO in higher wind.
Anyway, some sail comparisons below.
7.5 Gator on top of an 8.0 Foil Glide
7.0 foil glide on top of an 8.0 foil glide. Not the similarity in clew position and the leech extension above the boom
6.0 foil glide on top of the other two. Similar cut to the 7.0 but less luff length as well. 7.0 and 8.0 have similra luff length. Also I tried to line up the feet and wasn't perfect but I do think there's some difference there too
Also, grabbed a 550 front as the cheapest pathway to a new PB. I cracked a new minimum jibe speed of 11.3kts with this 7.0/725 setup. I think there's a lot of room to get better on that stat on all the race wings, but I was surprised at how good I was doing having never run that setup before and getting about 30% of my jibes above the 9kts threshold.
I think that will be sufficient gear to basically keep extending and wearing out these sails until the next gen of foils comes around, or maybe the one after that...