Zezo forum:

Post by zezo | 2017-10-22 | 17:51:42

It looks like the foils don't work in the VOR.

I'll probably remove the foil effect from the polars later today, and replace the "6% extra speed" option with "foils" as the effect can be calculated easily at runtime.

17 Comments

Post by marcusbelgicus | 2017-10-22 | 18:27:12

Thanks Cvevan, this is a good idea, we can see the effect of foils.

Post by zezo | 2017-10-22 | 19:23:16

My testing boat (w/o foils) is ahead of the official one.

Foils removed. Will be added back via checkbox at later date, because I want to test the changes for a while. The 6% extra is close enough in downwind foiling conditions.

Post by meteo79niort | 2017-10-22 | 23:35:34

Hi Cvetan,
how do you test foils ? we don't have more than 16 Nds ?

Post by zezo | 2017-10-23 | 07:08:54

So far it looks that foils start acting at 11 kt, being at 100% at 16. That means 50% effect at 13.5.

It could be something else, of course, but there was obvious difference in client- and server- side speeds.

We should see about 16 knots of wind later today and collect more statistics.

Post by zezo | 2017-10-23 | 11:28:38

TWA TWS BS(C) BS(S)
137 15.1 16.1 15.43

Post by meteo79niort | 2017-10-23 | 09:00:22

Ok thanks. I didn't take foils. I'm in SO on this leg ;-)

Post by Banjo69 | 2017-10-23 | 11:48:26

there seems to be more speed added to polish and foils than the 6% as I am seeing 16 kn and you are reporting 15.75

Not a big deal but still

Post by zezo | 2017-10-23 | 11:57:35

Right now I see you data as
TWS 15.8
TWA 141
BS 16.0

Which exactly matches my polars with "pro pack" on

You are probably seeing BS of 16.6 or 16.7

Post by zezo | 2017-10-23 | 12:21:01

Oooops. Just got above 16 kts of wind and it looks like the foils kicked in server-side.

Post by hipolou2 | 2017-10-23 | 13:14:36

les foils ne fonctionnent pas:

ce matin:

vent 15.96 bateau: 16.5 TWA 140
vent; 16.0 bateau; 16.7 TWA 140
vent: 16.1 bateau 16.8 TWA 140
vent : 16.6 bateau 17.2 TWA 140

Qu en pensez vous?

Post by zezo | 2017-10-23 | 12:47:31

Oooops above 16 knots again and the foils don't work this time.

But I've written the checkbox code. Now "Foils" gives you 4% extra speed at TWS between 16 and 35 and TWA between TWA 80 and 160, as per the polar data.

Post by zezo | 2017-10-23 | 13:05:39

Oooops 3. It looks like the foils only work on starboard tack.

Post by zezo | 2017-10-23 | 13:53:07

TWA 139, full option boat
starboard tack

TWS BS - server
16.21 17.14
16.28 17.23
16.36 17.32
16.44 17.41
16.37 17.33
16.30 17.25
16.24 17.18
16.17 17.11
16.10 17.03
16.01 16.94
15.95 16.83

port tack
TWS Speed (client)
15.84 16.20 (16.8)
15.84 16.21 (16.9)
15.93 16.33 (17.1)
16.04 16.47 (17.2)
16.24 16.68 (17.2)
16.49 16.79 (17.4)

Post by meteo79niort | 2017-10-24 | 00:28:39

So, you confirm ? the foils only work on starboard tack? I will tell them

Post by zezo | 2017-10-24 | 00:56:07

It looks like that, and I've seen two boats crossing on opposite tacks, same TWA showing 1 kt of speed difference, but there are many factors at play here. Data is not exactly real time, different boats are lagged different amount and so on.

Still, if I could take a look at the code I'd make a bet on a missing TWA=abs(TWA) statement somewhere in there ;-)

Post by meteo79niort | 2017-10-24 | 18:25:47

I noticed several positions on 2 tack this morning. There is a big difference.
I did not do the calculation on the boat without the foils. Maybe tomorrow morning
http://www.zupimages.net/up/17/43/xxuz.png

Post by zezo | 2017-10-24 | 18:34:25

Yesterday I also noticed 0.2 - 0.3 knot difference at 22 kt boat speed even on starboard.

But it's hard to correlate exactly because the display is rounded to 1 decimal digit, and that introduces some error.

Then, even if we collect all kind of evidence VR will say "oh, those are gusts like in real life"