On the other forum there's a thread on Stretching the glide. Birds made this comment:

'Strong wind gradients can mean over shoot or under shoot, and most dont realise it till they are init.
If your donk goes quiet and you setup for that spot that just happens to be at the bottom of the slope youv practiced many times, a head wind will have you overshoot, and a tail wind will see you fall short with steep, strong gradients.

Just sumthn to keep in mind.'

Don't want to get into anything over there, but I am a little confused - is it not the opposite? If I have a strong headwind will I not land closer, shorter and with less groundspeed given the same descent angle and speed, than if I have a strong tail wind. Same with turns around a point - tail wind I travel further from my point, than with a headwind

Jeff- If you have a head wind ...and you set up your glide slope...as you get closer to the ground...the wind gradient has the headwind lessening the lower you go....and thus you start to gain groundspeed with the smaller head wind...and you will over shoot if not corrected for.

Likewise if you have a tailwind and are trying to reach a landing place....your glide slope that at altitude makes it look like you are going to make that patch...
You will typically start having less of a tail wind and now you may fall short of making that patch.

Birdy is spot on.

Well, I'm confused to me Jeff is right, if you are aiming for a spot in your glide slope, I would think that a headwind will see you falling short of your target? If I am gliding for the spot in no wind then a sudden 20Kt headwind pushes me back, I will have to readjust the glide slope to get there.... Like, if I am standing on a bridge over a river looking at a rock on the bottom, if the water is not flowing, I can dive in and go to the rock.... if the water is flowing towards me (head wind) if I dive the same aiming to get the rock, I will fall short of the rock because of the current pushing me back the way I am coming from?

I will wait and see what others say, maybe I am reading it wrong?

Edit: I still cant get his concept, because if the engine stops, you don't just set up a glide slope to reach a spot, then expect to close your eyes and then expect to be at your spot when you open them again..... you evaluate what clues there are to what the wind is doing where you want to go and you constantly adjust your glide slope until you flare and land, you continue flying the machine until it is on the ground... you do everything that physics allows you to, to get to where you are going...... and that might mean spiralling once or more to line up with your spot or even timing it so the last bit is downwind, so when you do your final turn into wind and flare (at the same time) you put plenty of energy into the rotors for a hopefully gentle touchdown?

Dunno, still don't know what his reasoning is? but it appears to me you are right Jeff

Head wind creates extra lift. Extra lift will carry you further. Birdy is correct.

Here we are introducing another unknown variable - wind gradients. Simple question - if I am at 1000 feet and I wish to glide 3000, a 3:1 glide ratio being a reasonable number for gyros, will I glide further in a strong headwind or cover less distance. As I said - use the turn around a point analogy - I have to turn sharper with the wind behind me and shallower with a headwind to keep the same distance relative to a point.
I understand the headwind may decrease as I get closer to the ground, but it's still a headwind, and I will land shorter if I am landing into the wind, than if I am landing (same airspeed) into it.

Airspeed is the same. Lift is the same no matter the windspeed if I keep my airspeed the same.
A strong headwind pushes me away from a point not towards it. If the headwind is strong enough I will actually land going backwards.
Those 'hovering videos actually show people landing further back in a strong headwind.


I am going to have to completely change how I land if Birdy is correct.

But part of the process of an engine out landing in a confined LZ is to continually make adjustments all the way down.... so all you would do is lower the nose further (in your power off descent) or if you can't, then spiral to come back to a position you can regain your target landing point? There is also no reason in a gyro, why you cant approach your ELZ from downwind glide, so that your turn and flare becomes into wind with said lost of energy in the rotors and less ground roll (if any)

I guess where I am getting confused comes back to my engine out on that video.... I am quite happy to point the nose down like I am trying to play 'lawn dart' .... if I am doing that, a wind from the front (which is now the top) will push me short of my desired LZ which is opposite to Birdy's theory?
And, like I said, if I had time and my LZ was directly below me, I would do a 180 so I am going with the wind for the energy storing turn and flare, or if the wind is going to carry me too far downwind of the LZ, then I would 180 again to be into the wind for a straight flare....

It depends what you call a glide lope and how steep you are prepared to aim at the ground?


Don't change anything Lofty, you are flying perfectly safely as you are

When you have a real engine out and the only ELZ is below you, you might not be able to or have time(altitude) to set up a glide slope, or watch instruments, you just do whatever you have to do to get there..... if you have to land in a vertical descent, that's what you do.... that is the exact reason I love gyros.... in a FW, you have no opportunity to get into a vertical descent, because you will stall and either mush, or drop a wing.... but the FW is out of your control... a gyro.... as long as the whirly things are still on top and turning freely, the most you will do from a VD to the ground (unless you hit the side of a hill/cliff, land on a 100' tree canopy or hit other obsticals/power lines/bridges etc etc) is go for a roll over as the rotors beat themselves to death and you get covered in whatever they dig up and trow at you, in the 5 or 6 revolutions it takes for them to stop.....

When you are in a big nose down like I was, where I was going to touch down was the only bit that wasn't moving (in my view) where I was not going to make it to, appeared to be moving away (the direction I had been travelling) and where I was not going to get to because I had passed it, appeared to be disappearing under the machine.... if that makes sense?

Yeah, I know. Just I think Birdy again is creating a lot of confusion. Let's forget about engine outs for a second because it applies to any constant power setting, engine out or not. If I am coming in to land at a constant power setting (zero power and upwards), set up at 55 knots and the windsock is standing blowing straight out at me with say a 15 kt headwind, I am going to land much closer (everything else being equal) than if the windsock is flaccid or than if I have a tailwind.
I understand the concept that with strong headwinds or tailwinds there may be bigger gradients as I go lower, and I have to compensate accordingly, but with any headwind my landing point from any given height will be closer to me than with any tailwind, even if it is less than it was higher up.
As an aside, that's why it's possible to hover in a gyro into a strong headwind because one is not translating forward relative to the ground, but Birdy would have a problem with that.

Exactly right Lofty I totally agree

Your thinking is faulty because you think of your machine as a sail instead of being an airfoil.
Helicopter pilots understand this better as we practice engine outs we do have a steep angle coming down but with head wind we really have to cut engine way out to hit the spot.
Note that during helicopter autorotation we don't change pitch of the blades and we shoot for the recommended IAS.
Checking the collective will give you extra distance but you are bleeding rotor rpm.

Gabor, in a gyro and If I am approaching a runway and I am at 1000 feet and set up for 'best glide' in my MTO, you are telling me that in a headwind I have to be further away from the threshold, than if there is no wind or a tailwind?
I think this would be bad advice, at least in a gyro. I know nothing about helis. By this argument how do you explain changing turn steepness when turning about a point with strong winds? If this argument applies we would do the opposite of what we do with turns around a point.
If I am turning base to final in the pattern with a strong headwind down the runway, I have to turn base much earlier than if there is no headwind down the runway.
The bottom line is that for a given glide speed (airspeed) one will translate the same distance through the air no matter what the windspeed is doing. But if the airmass is moving one way or the other you will move with the airmass in the direction it is moving, and your ground distance translation will be the sum of your translation through the air plus the translation of the airmass over the ground. Pure physics, pure vectors.
Answer this question - if I am coming in to land at 55 knots (airspeed), lets say one second to touch down. If the head wind is 20 knots what will be my speed relative to the ground in that last second - 35 knots. If I have a 20 knot tail wind, what will my groundspeed be - 75knots. In that one second will I travel further till I touch down at 35 knots or at 75 knots?
It has nothing to do with whether my machine is a sail, an airfoil, a parachute, or a gyro. It's probably closest to a parachute.
I guess if I was having this discussion with Birdy or Beaty I'd be told I'm wrong because I'm not using aeronautical definitions. Now I am sure in your mind as in Birdy's mind there is something in the semantics that I am missing, but again this is pretty confusing to lay people like me, just like hovering.

Did an auto to an open field in a Bell 47 the last 3 feet above the ground we just coasted along in ground effect for 1/4 mile
I asked Ken if he wanted for me to extend it more or go around. Winds were 25 mph right on the nose.

In head wind you will be at steeper descent Jeff because of your IAS will tell you to do so.
If you keep 50 KTS airspeed the approach will be steeper to compensate for extra lift otherwise you'd overshoot no two ways about it.

In helicopters we teach normal and steep approaches. With steady engine set no peeking at the IAS you would understand it immediately.

Show me how you do that in a gyro....

Gabor, where do you get this? Descent angle of the gyro itself relative to the horizontal will be identical in a gyro for any given IAS, no matter which way the wind is blowing. Sitting in the gyro, I will not be steeper at 55knots IAS irrespective of windspeed.
Relative to the ground and viewed from the ground, you are correct, my hypotenuse will be longer with a tailwind, hence the angle from landing point to my point in the sky will be smaller, but so will the distance along the ground. Pure vectors, pure trigonometry. And yes with a strong headwind if I were to predict my landing point I will look down at a steeper angle; why? Because my landing point is closer to me!!! Why, because I will not translate as far across the ground, but my nose angle to the horizontal does not change. If I point the nose down more steeply my glide speed will increase.

The lighter the aircraft, the less momentum you have and therefore the lower the effect on your airspeed.

OK, so now my gyro gets lighter in a headwind - it weighs 560 standing still, how much does it change at 55knots, engine off, upwind vs downwind?

I reckon the lighter the gyro and the more draggy it is, the less momentum it has, so the more the effect (the headwind has) on the airspeed?