Sorry, newbie question again but right now here in the UK its pretty windy (somewhere between 15 and 20 MPH if iPhone weather is to be believed) and i was wondering what sort of windspeeds the Phantom can cope with before RTH functions etc fail?

Thanks!

13 to 17 MPH is the maximum wind speed recommended in the manual.
Don't forget that at altitude the wind speed can be much higher than on the ground.

went out myself today.. quad was at a 5-10 degree angle trying to fight the wind.. landed and went home..

rth would only fail with gps lock fail.. if the quad losses all its power while trying to RTH it will land where it is

I would not fly in those winds.  The GPS does an amazing job of holding position but with high winds you are asking the little motors to work bloody hard to overcome wind input as well as managing the controller input..  The other risk is if you lose GPS or switch to atti, your phantom will become a famous film title--- gone with the wind!!!.  

Thanks guys, thats kind of what i figured. I will spend time sticking more stickers onto my transmitter to remind me what to do instead!

You can get some really cool effect when filing in ATTI mode in the wind but generally, I try to keep it under 5-10 mph; it's much more enjoyable at lesser wind speeds.  If you need a rush, go fly but keep it lower, the higher you get the more the Phantom can be pushed around.  Oh, and keep it close and up-wind of yourself, that way it's easy to bring home and your not bucking the wind when you are running low on battery.

There's lots of pioneers in Youtube
but remember do not fly too high because that the wind speed will increase dramatically to beyond your control.

I will fly my ancient P1 with a light load in strong winds - just to jump up 100 feet and get a still picture...but flying the P2 with cameras, gimbals and loads is probably not good in over about 10-12 MPH. If you are doing close-in (near the ground and near you) work, that's a different thing. But, yeah, winds increase vastly as you get 100+ feet up.

This is how I calculate wind speed for the altitude I plan to fly at:
The wind profile power law is a relationship between the wind speeds at one height, and those at another.

The power law is often used in wind power assessments[1][2] where wind speeds at the height of a turbine (>~ 50 metres) must be estimated from near surface wind observations (~10 metres), or where wind speed data at various heights must be adjusted to a standard height[3] prior to use. Wind profiles are generated and used in a number of atmospheric pollution dispersion models.[4]

The wind profile of the atmospheric boundary layer (surface to around 2000 metres) is generally logarithmic in nature and is best approximated using the log wind profile equation that accounts for surface roughness and atmospheric stability. The wind profile power law relationship is often used as a substitute for the log wind profile when surface roughness or stability information is not available.

The wind profile power law relationship is:

u/ur = (z/zr)α
where u is the wind speed (in metres per second) at height z (in metres), and ur is the known wind speed at a reference height zr. The exponent (α) is an empirically derived coefficient that varies dependent upon the stability of the atmosphere. For neutral stability conditions, α is approximately 1/7, or 0.143.

In order to estimate the wind speed at a certain height x, the relationship would be rearranged to:

ux = ur(zx/zr)α
The value of 1/7 for α is commonly assumed to be constant in wind resource assessments, because the differences between the two levels are not usually so great as to introduce substantial errors into the estimates (usually < 50 m). However, when a constant exponent is used, it does not account for the roughness of the surface, the displacement of calm winds from the surface due to the presence of obstacles (i.e., zero-plane displacement), or the stability of the atmosphere.[5][6] In places where trees or structures impede the near-surface wind, the use of a constant 1/7 exponent may yield quite erroneous estimates, and the log wind profile is preferred. Even under neutral stability conditions, an exponent of 0.11 is more appropriate over open water (e.g., for offshore wind farms), than 0.143,[7] which is more applicable over open land surfaces.

Just kidding, I do not do this!!!!!!

I flew on Tuesday and did not go any higher that 100ft, it was a little windy but not like Wednesday, or today Thursday looks bad here - GROUNDED!

I've flown in 20mph+ winds.
It's stressful, and the airframe has to constantly fight its way.
I've had waypoint missions get stuck in the air trying to make it to the upwind waypoint...
Once you get used to it, it's just another routine.

If you wait for dead calm or little wind, you won't fly much where I live.
The wind is your friend!

Fly up wind so coming back is easy

I have flown in 34KM/H (Approximately 22 MP/H) winds, but I don't much enjoy it nor suggest it. I also did not go too high, maybe 40 FT most of the time, and occasionally 100-120 to get a quick still.