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-   -   Strong Cross Winds (https://www.pprune.org/rotorheads/334237-strong-cross-winds.html)

helipan 8th Jul 2008 12:56

Strong Cross Winds
 
I have to land regularly in a tight area (cannot fly over due to buildings)which has a cross wind (90 degrees to the helicopter ) at times in excess of 20knots, at the moment I do both
· come in with the cross wind on my left but as always as I pull the collective to hover to land I get a little wobble,
· come in with the cross wind on my right, but that involves turning down wind in a hover taxi situation (as I have a carried out my decent before I turned down wind) and losing all my airspeed before turning the nose with the cross wind 90 degrees’
The last one feels more comfortable but it does go back to the question of no airspeed!
Any comments or better options?
Would also would love to get rid of the wobble at the end ?
thanks

Johe02 9th Jul 2008 07:18

Come in crosswind and just put a 'hockey stick' in it at the end, if you have room? Eg 20ft?

Or anticipate the lever and smoother in with the power. . ?

[email protected] 9th Jul 2008 11:36

Why not try flying in sideways with an into wind heading - or gradually cross control during the approach so that as your speed reduces, you yaw further into wind. No airspeed and a downwind turn at height sounds less than ideal.

The wobble when operating with crosswind from the left may be due to interaction of the MR vortices with the TR - typically a wind from 10.30 to 11 o'clock will produce this - the retreating side of the disc will have higher AoA and therefore a more powerful tip vortex than the advancing side.

helipan 19th Jul 2008 23:11

Thanks for the info,
will try it out next time !

KrisRamJ 20th Jul 2008 01:34

Be careful if you're slowing with a right crosswind, you could easily run out of power or left pedal if you're hot/heavy/high. If you know you've got the power then this is the preferred direction though.

Left crosswind can cause LTE - either M/R interference when the wind is from your 11 'o' clock or T/R VRS if the wind is from 9 'o' clock. Hence the 'wobble' you described.

Either way, be careful with crosswinds. If you can I'd advise maintaining airspeed crosswind and 'hockey stick' it in as the previous poster advised.

The above assume you're flying 206/R44 etc - if you're in an AStar the rotors turn clockwise so it's the opposite wind direction.

TheVelvetGlove 20th Jul 2008 16:44

If DA is not an issue, and I have a good power margin, I prefer to come in crabbed to the right with a turn into wind on very short final.

If DA is an issue, or I have a small power margin, then I prefer to come in with the wind off the left.

I used to have to go in and out of a hospital pad that required (with prevailing winds) that we flew the entire approach downwind, even when winds were 20 kts....just had to take it really slow as we approached loss of ETL on approach, and then take it even slower from there.

But hey- every helicopter has it's quirks, and every pilot has his method of dealing with them.... good luck. I don't think there are any hard and fast rules for any approach. :ok:

B Sousa 20th Jul 2008 22:01

Crosswind?? In a helicopter? Whats the matter with coming in sideways, nose into the wind.........
If its that tight that you must always come in with a crosswind, someday your gonna break something.


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