Cross Wind

[Phil May]

I went down the club for 10 this morning, there was a 10-15 mph cross wind and it put me off a bit. I waited an hour but no change, as I was about to pack up two of our examiners turned up and convinced me that been as our field is on the low-lands near the coast i've got to learn cross wind take off & landings.

I spent 3 hours learning these, with a  good result.  Also learned to fly flat turn ciruits(that was odd) rudder and ailerons opposite ways did not seem right.

Glad I stayed now.

[simon barr]

Well done Phil. It's satisfying, isn't it, to learn a new flying skill...

[Simon Chaddock]

Hi Big Phil

Flat turn circuits? I trust you kept the speed up.

Aileron and rudder "the wrong way" when flying slowly is a good way to start a spin!

 

[Gemma Jane]

It's a perfectly normal step in rc flying to teach co-ordinated rudder and aileron control Simon, by  using the opposite or 'crossed controls'

 

Cross controls have little to do with spin entry and are in fact one of the methods used to land full size in a cross wind (so clearly not likely to induce a spin when flying slowly). It can make passengers throw up though.

 

I can see it made perfect sense to fly flat circuits whilst learning cross wind landings.

 

Edited By Gemma Fairchild on 05/07/2009 14:25:00

[Tim Mackey]

Yes I always thought that large rudder and elevator inputs caused the spin....thats how I do 'em anyhow.

Surely the application of opposite aileron to the yawing rudder is needed in order to keep things flat....  in the "flat  turn" ?

Mind you I am rubbish at aerobatics compared to our club gurus

Edited By Timbo - Moderator on 05/07/2009 14:36:02

[Gemma Jane]

Spin entry Tim is essentially

 

Stall

 

Drop a wing

 

Rudder applied in the direction of the wing drop

 

 

Yep a flat turn is just as you described aileron one way, rudder the other, that is where 'crossed controls come from'

 

The only thing that needs to be considered is that it isn't the most efficient form of flight, so a little extra power is needed to maintain height, that is all.

 

It's excellent way to land in a crosswind, you put one wing down into the wind and hold the model on a line with opposite rudder all the way in.

Edited By Gemma Fairchild on 05/07/2009 14:51:02

[Myron Beaumont]

Especially on a Piper Cub I found out many years ago !

[Stephen Grigg]

I  now set up my models with aileron rudder mix.This has given me the confidence I need.If I put opposite rudder in when the mix gives rudder and aileron together,what happens?

[Martin Harris - Moderator]

Depends which is the slave channel but almost certainly the master would be aileron unless you've been taught rudder only so there'd be no effect on aileron.

 

Just a word of caution if you apply crossed controls approaching a stall this CAN increase the likelihood of a wing drop.  Certain gliders I used to instruct in would only enter a spin if you applied opposite aileron - due to the increase in AoA and induced drag from the downgoing aileron.

Edited By Martin Harris on 05/07/2009 15:51:55

[Gemma Jane]

I think what is important here Martin is Big Phil had some great help and instruction from an examiner, good control of models in crosswinds is a big confidence boost. Being told it is a good way to enter a spin is not helpful. No stall no spin is the message.

 

 

 

 

[Dusty]

Defo power in x control input, your stall speed is higher in x wind! You have a foundation of a incipent spin with x controls so always be aware of your speed, faster is better... Aileron in a spin increases the stall further, oposite rudder applied, full up elevator should be held during a true spin... If your model has flaps dont use them in x wind, makes things easier.

[Phil May]

This seems to have caused a bit of a debate. I'm only going by  the advice given by two examiners one of whom has a 'C' cert' for both heli and fixed wing. 

My flat cicuits were at height and at 1/3 throttle, but one other smarty-pants was doing inverted flat circuits at about25 feet(vey cool looking) with his stick.

[Gemma Jane]

Yep Phil and it's fine, you keep at it.

 

 

[Dusty]

Not a debate BP its principles of flight, once you know what effects the wind etc does to a plane, what control inputs to put in different conditions then the plane can be flown, just takes time a practice and dont be afraid! The rudder is a very effective control surface and when used it makes a huge difference..

 

Aileron only = roll then yaw

 

Rudder only = yaw then roll

 

Opposite rudder causes a adverse effect hence the need for power, x wind is good practise for knife edge? elevator becomes rudder, rudder becomes elevator... Its there to be used not just for steering!

[simon barr]

Blimey! Big Phil only posted a thread because he is chuffed with his acheivements and new found skills. All the above is correct in one form or another, but as Gemma says, keep at it...  Well done Phil!

[Stephen Grigg]

Thought of this thread last night Phil,when I arrived at the strip.Very windy in the wrong direction and had 2  electrics.Had great fun especially the landings but enjoyed myself

[fly boy3]

Can the principle of opposite control inputs (rudder/aileron) for cross wind landings be used for take offs, and if so can it be used when a 90 degree cross wind to direction of take off is blowing.flyboy3

[Martin Harris - Moderator]

On the ground you'll need rudder to counteract the yaw from the wind hitting the fin.  Depending on the strength and direction this can add to or subtract from the natural yaw from the prop effects.  The ailerons are used to keep the wings level - harder work on a high wing.

 

Once in the air things change a bit as any side loads on the wheels disappear and the model is free to drift in 3 dimensions. The wing low / opposite rudder (or more usually the crabbing technique) can be used to maintain runway heading although obviously it's not as critical as in lining up a landing approach.

 

 

[Delta Whiskey]

Coming from flying heli's first, it seems natural for me to use the rudder constantly when flying my fixed wings now, and the other week, I saw a few jets at heathrow landing at an angle just before finally straigthening up at touchdown, and I had to do the same down at the field in a strong cross wind the other day, very satisfying to finally pull it off !

 

And well done Phil !

Edited By Delta Whiskey on 07/09/2009 07:56:59

[fly boy3]

Hi all, if the wind is 90 degrees to the runway,would it be feasible to try a x wind landing or not fly at all. Take off into the wind is possible, but due to other restrictsions, low hedge,fence etc landing in only one direction is possible. A light  wind and an 8llbs of model may have a chance.but you have to come in fast. Thanks flyboy3

[David Turner]

Crossed controls, as Simon says, can lead to inadvertent entry into a spin.  You would be well advised to heed his advice. You are, in fact, establishing one of just two essential preconditions for a spin...the presence of yaw.

 

 Which is not to say that you should never fly in a "crossed" condition... for certain manoeuvres, it is essential to have crossed controls. But, IMO, the aeroplane should be treated with great respect when flown in this manner.