Telling crosswind direction

[kaha 205]

You can tell the direction of crosswinds like that: go to outside view and center behind the aircraft. If the camera is to the right of the centerline of the aircraft there is a crosswind coming from the right. 

https://www.dropbox.com/s/2pe627ecsyyiowe/Crosswind_Left.png?dl=0

https://www.dropbox.com/s/hwf498xb2zl1v0l/Crosswind_Right.png?dl=0

Karl

[GearUp180 55]

15 minutes ago, kaha said:

You can tell the direction of crosswinds like that: go to outside view and center behind the aircraft. If the camera is to the right of the centerline of the aircraft there is a crosswind coming from the right. 

https://www.dropbox.com/s/2pe627ecsyyiowe/Crosswind_Left.png?dl=0

https://www.dropbox.com/s/hwf498xb2zl1v0l/Crosswind_Right.png?dl=0

Karl

Thanks for sharing!

I wonder how you do it in a real plane without external view.

[kaha 205]

1 minute ago, GearUp180 said:

Thanks for sharing!

I wonder how you do it in a real plane without external view.

That's why I do not go to external view anymore.

Karl

[Janov 2,383]

31 minutes ago, GearUp180 said:

I wonder how you do it in a real plane without external view.

That is one of the last unsolved problems in aviation: Where does the wind come from?

There is literally no way to find out, people have suggested putting up red/white "tubes" of fabric to show the direction, use instruments to read it (like they used to have on church steeples), or even use some sort of method to record these readings and then transmit them with the use of invisible waves...

Clearly all these folly ideas were rejected immediately and us real pilots long for a method to determine wind direction as nifty as switching to the external camera and judging wind direction that way.

 

[RobF2 150]

Actually this is good to read - sometimes I worry my rudder pedals are misbehaving - nice to know other people see this from wind shifts  🙂

[Chock 17,769]

I open the DV panel, lick my finger and stick it out into the slipstream; this will guarantee that you will always be landing into the wind because it is always coming from the front. Some fools have suggested that this is the blast from the propeller, but obviously they don't know what they are talking about. 😉

Alternatively, you can always look at the windsock. Each red or white segment represents five knots of wind when it is extended vertically, so in this picture, you can tell the wind is at 17 knots. If it is flapping about, then it will be gusting to 17 knots:

Observing cloud shadow movement on the land can be useful, but it won't tell you what the wind is doing at very low level. Similarly, the steam from cooling towers or industrial chimneys is a good clue. Cloud streets can also help; a cloud street is a line of cumulus clouds, which if you look along it to the obvious source of the thermal which formed them all  (usually a town or some such which is radiating heat), can tell you which way the wind is going.

You can actually also see the cloud streeting in that windsock picture: notice that the distant cumulus clouds get thicker in the direction of the wind. This is because they are forming up and then drifting with the wind. Their shape is also sometimes a clue, they are sometimes thicker and more bulbous on the lea side as they boil up.

In bad weather, animals will often shelter in the lea of dry stone walls and hedgerows, so if you see a bunch of cows or sheep all near a wall or hedgerow in windy and rainy weather, you know what the wind is doing at very low level, this is good info for forced landings and is a favourite trick among glider pilots if landing out and picking a field to go into.

If you are over water, you can usually see the wind effect on the water's surface, similarly, at less than about a thousand feet or so, you can usually see the movement from the wind going in waves across crops or tall grass.

If you can see the shadow of your aeroplane and it isn't a particularly powerful aeroplane, you can sometimes determine drift from the way the shadow is going. I use that quite a bit with gliders on slope soaring, where since those things stall at about 35 knots, you can sometimes even see your shadow going backward across the terrain. You do have to be careful to look out for others when doing that, but it is kind of cool to see yourself going backwards and if that happens, you will invariably going up like a homesick angel with the vario wailing away like crazy.

Obviously all these aerial observations are only good for landing, but the cloud streeting, smoke drift, grass movement and the windsock are good clues you can gather when on the ground.

Top take off safety tip in a crosswind: Most of the time you are asked to stay on the runway heading for half a mile or so after having taken off by offsetting into the crosswind to stay on the extended centreline, but there is an exception to this. Imagine you lift off and then your engine starts spluttering and you think it might possibly stop; if this happens, do not correct for wind drift in an attempt to stay on the extended centreline. The reason for this is, if you manage to make it up to enough height to try the 'impossible turn' back to the airfield, when you turn into the wind to come back, you will be off to one side of the field from not having corrected for drift and so you'll probably only need to turn about 160 degrees into the wind to be in with a shot at making the airfield and can also be guaranteed to be coming into a headwind which will reduce your touchdown speed, whereas if you'd tried staying on the centreline, you'd need to swan-neck your turn through more than 180 degrees to be able to see the airfield.

Edited May 15, 2021 by Chock

[Glenn Fitzpatrick 3,799]

14 minutes ago, Chock said:

I open the DV panel, lick my finger and stick it out into the slipstream; this will guarantee that you will always be landing into the wind because it is always coming from the front. Some fools have suggested that this is the blast from the propeller, but obviously they don't know what they are talking about. 😉

 

It could be the propeller becasue when I do that in a hot air balloon there is no wind... though apparently in jet aircraft you still get a wind from the front even without a propeller ? very confusing. What about helicopters has any  one tried that.

The other thing I tried was hanging a weight on a bit of string in the cockpit so I know which way is down but something must be wrong with my string because even at 60 degrees bank it gets stuck in a vertical position.

[Chock 17,769]

Interestingly. I've noticed that the wind is always going upwards when I'm in a vertical dive. 🤣

[Janov 2,383]

Here is my trick: I look at the wind arrow on my nav display 😁. Unfortunately it doesn´t work until I lift off...

When you fly about and want to correct for wind drift - do it like the bomber pilots did when calibrating their sights: Fly over a known position - then fly for a bit with known heading and airspeed. Now measure your new position, compare where you ARE with were you THOUGHT you´d be. You have just measured the winds aloft 😉

This all boils down to the golden rule of navigation: If you know where you are, you can be where you want 🙂

 

Edited May 15, 2021 by Janov

[Chock 17,769]

25 minutes ago, Janov said:

like the bomber pilots did when calibrating their sights

If you look at a lot of footage of WW2 daylight bomber formation pics of things like B-17, B-24s etc, you will notice that the lead pathfinders have dropped smoke bombs to assist with judging the wind.

The B-17 (and other bombers like it) had a downward looking scope at the navigators station which had parallel lines engraved on it, this could be rotated to match one of the lines with a ground feature, then you could observe if the line stayed on the feature as you flew over it, if it didn't, you would rotate the scope so the lines were at a suitable angle so the feature would stay on the line, from this you could determine wind drift. You can actually do that in the old Microprose B-17 sim, and they are currently making a new version of that sim with the B-24 in it too, which looks very cool.

German bombers in WW2 used a radio beacon system which did a similar sort of thing, which was called Knickbein. It worked in a similar way to how you tune two VORs in and are able to determine your position from that, and you can sort of do the same thing yourself with VOR radials and a few quick calculations. But the Luftwaffe pilots went one better with their system and flew along one directional beacon, so that they could determine drift from the DF loop, when they crossed the other directional beacon, the radio system would detect this and  would automatically trigger a clockwork timer which released the bombs automatically at a predetermined point. the lead bombers would drop incendiaries and flares to assist in determining wind drift and to set the target on fire to help the next wave of bombers. This was one of the reasons why the Luftwaffe were able to bomb cities in the UK in the Blitz with remarkable accuracy in spite of the blackout.

The Germans were able to do this with the UK because they had occupied Scandinavia as well France, and so it was easy for them to position two directional beacons in those countries, both of them angled to point at a specific location over the UK, and since they were at about 90 degrees to one another, this was pretty accurate for positional data, and it does also tell you that you can determine drift from VOR beacons in modern times.

The downside of this system for the Luftwaffe, was that in order to use such a system, the bombers had to fly at a specific altitude for the automatic bomb release to accurately time the fall of the bombs, and there were of course also two massively powerful radio signals being beamed across the North Sea and the English Channel, both pointed at the initial point for any attack. From this, the Brits were usually fairly sure which city was going to 'cop it' that night, and they usually knew both the direction and altitude at which the German bomber would arriving from assisted by the coastal radars they had, so even before they had suitable radar for night fighters, the RAF could put standing patrols up in likely spots and just wait for the bombers to arrive. That's when air warfare changed somewhat radically to include jamming signals, spoof signals and all that kind of sneaky stuff.

Edited May 15, 2021 by Chock

[MarkDH 234]

Apparently cows point downwind, though it seems unlikely this is simulated in MSFS. If you want to do it methodically for bush flying, you can fly at a constant aurspeed over your threshold in different directions and note the ground speed shown by the GPS.

[Chock 17,769]

2 minutes ago, MarkDH said:

Apparently cows point downwind, though it seems unlikely this is simulated in MSFS. If you want to do it methodically for bush flying, you can fly at a constant aurspeed over your threshold in different directions and note the ground speed shown by the GPS.

You might be interested to know that the RAF teaches its fast jet pilots to judge altitude at low level by whether they can see the legs on sheep; apparently when you can see their legs, that's about 200 feet AGL. So if you are a dictator of some foreign land and you want to spoof the RAF, either get some really big sheep, or don't have them at all. 🤣

Edited May 15, 2021 by Chock

[Glenn Fitzpatrick 3,799]

1 hour ago, Chock said:

You might be interested to know that the RAF teaches its fast jet pilots to judge altitude at low level by whether they can see the legs on sheep; apparently when you can see their legs, that's about 200 feet AGL. So if you are a dictator of some foreign land and you want to spoof the RAF, either get some really big sheep, or don't have them at all. 🤣

Stick forward sheep get bigger, stick back sheep get smaller.

[sd_flyer 6,073]

When you look outside  window or on your instruments and clearly  see a drift! There  must be only to choices: a crosswind or mechanic didn't rig your airplane right! 🙂

[jmdriskell 178]

A very windy discussion!