Gally2, wiggy mentions max drift. There is a rule of thumb for this, which is windspeed/TAS in nm/ min. Ie 25 divided by 5/4 (75 in nm/min). Dividing by 5/4 is the same as multiplying by 4/5......4/5 times 25 is 20. Thus, for a 75 TAS, the drift cannot exceed 20 degrees. The trick is knowing how much of that max drift to apply. In your example it is easy since the wind is 95 degrees off your nose or 85 off of your tail. We thus use the max drift. So, heading 130 degrees with a 20 degree left drift gives you a track over the ground of 110 degrees.
The way to evaluate how much of this max drift is to look at the wind angle, ie the angle that the wind makes with the longitudinal axis of the aircraft. We use a clock code.....if the wind angle is 15 then we use 1/4 max drift...20 and we use 1/3. 30 equates to a half, 45 is 3/4 and 60 and above is max drift. In other words, we take the wind angle and liken it to minutes on your watch. Hence 30 degrees is 30 minutes, ie a half hour and thus half max drift.....45 degrees is 45 minutes, ie 3/4 of an hour so use 3/4 max drift. Get the idea?
The wind angle is actually the shorter angle between the wind and the longitudinal axis....thus, in your example is actually 85 degrees behind you....hence max drift. For the groundspeed, we use (90-wind angle) and then use the same analogy with the watch face. Thus (90-85) is 5. 5 minutes is 1/12 so, as the wind is marginally behind you then we add 1/12 of 25 kts to your airspeed to get the groundspeed. Thus, in my head, I would tell you that your groundspeed is 77 kts. In reality, for nav, I call that 75 and thus your eta is 4/5 of your distance to go, since you are effectively doing 5/4 miles per minute.
So, to answer your question, my head tells me that your track 110 at a groundspeed of 77 kts. The CRP5 will finesse this but I will be pretty damn close.....
Back to my 380....