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TWA bug
Publié : 31 mars 2020 20:06
par limelight
On the fast fastnet race, I've hit a strange bug:
Wind is 19.4 k / 58°
Program point 5 has set a heading of 104°, by my reckoning this makes TWA 46 (46+58 = 104)
but the programmer insists it is 35???

Re: TWA bug
Publié : 31 mars 2020 21:25
par Benoitsuomi60
Re: TWA bug
Publié : 31 mars 2020 23:45
par limelight
You must be right... but I was sure it was after the weather update. I waited for it on JV because it took so long to get the green... or so I thought. But you're right Prog 1 is at 19:54 so it's not yet the 'new' wind and I should be +12. Stupid me
This new time is such a pain and worse will come when we switch to winter time, the weather update will be at 3am and I'll need to get up at least 30 minutes before to do any sensible programming.
I'll stick to the team challenge since I've committed to it... but that's it. No more races for me till next Summer.
Re: TWA bug
Publié : 14 oct. 2020 21:30
par limelight
To whom it may concern:
I've identified a minor bug in RG's polar display after the recent modifications. I have reported it in the French forum but I want to make sure we English speakers are aware of it. The red TWA angle indicating best VMG is not always correct, so far the bug is the TWA when running, the close hauled one seems to agree with my calculators.
The differences in VMG are small, of the order of 0.01 knot, but every little bit helps so you may want to calculate the VMGs yourself and pick the corret TWA... or use my calculators.
Cheers,
John
Re: TWA bug
Publié : 27 oct. 2020 00:13
par limelight
There is still a little bug in RG's polars:
RG show 145 in red as the TWA giving the best VMG, but I find 142 is better:
With 145:
VMG = - 15.90 * cosine(145) = 12.9505 knots
With 142:
VMG = - 16.57 * cosine(142) = 12.9776 knots
Therefore 142 is clearly better, until this bug is fixed you had better do a hand check yourselves. RG's value is never far but is not always the best.
On the other hand, when going against the wind, I haven't found any dicrepancy yet.
Re: TWA bug
Publié : 27 oct. 2020 08:45
par blzblz
Hi limemight,
The VMG display has been fixed on the polar diagram and table, on the main interface and on the popup window.
Could you check with your calculation tool wether it is now ok or still not ok, please ?
Thanks in advance

Re: TWA bug
Publié : 27 oct. 2020 11:29
par limelight
Hi Blaise,
I checked with the Multi 50 med 18, and I now have perfect agreement between RG's polar diagram and my calculator.
Tomorrow I'll check a few different polars, but I think you fixed the problem.
Thanks,
John