Crosswind landings

[larsrulz 0]

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Right, but our 'landing gear' is much less sensitive to landing with a crab angle than an aircraft's is

Not mine!

Dave

I'd agree, and I'm young. My legs be hurtin' from my (~20 mph) standup crosswind landing saturday, and you don't want to see some of my archer landings yet that bird doesn't seem to notice!

I got a strong urge to fly, but I got no where to fly to. -PF

[Hooknswoop 19]

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Not mine! Tongue

Dave

I'd agree, and I'm young. My legs be hurtin' from my (~20 mph) standup crosswind landing saturday, and you don't want to see some of my archer landings yet that bird doesn't seem to notice! Tongue

You ought to see what can happen to aircraft landing gear set down with too much drift.

Derek

[Scrumpot 1]

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Watch how the pilot has to fly an otter in on a day with a strong crosswind. He will have to steer it into the crosswind to land.

Not the best of analogies though. When you say "turn", a fixed wing pilot (depending upon when they were trained and their particular proclivity) will generally be using even as much as 100% Aileron (bank) turn. A cross-wind landing involves perhaps heavy rudder, to counter the cross-wind ...but you will note that is a piece of equipment as well that a canopy just does not have! Therefore thinking of landing as such "in a turn" in my mind is (potentially) a bad picture.

An "offset balance" on toggles, or toggle pressure as alluded to in another post above (quipping about those that grouse about ...did you see that gust -when it is THEY that do not have this capability), is probably a better direct description. Although I fully understood, I can see this one getting a bit misinterpreted by some.

Bottom line is that you need to fly your canopy all the way too (and then even sometimes while ON) the ground. Not the other way around.

-Grant

coitus non circum - Moab Stone

[Scrumpot 1]

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The important point here is that canopies are not capable of a sideslip because they lack a rudder.

And POWER. Don't forget that other all-so DIFFERENTIATING (and oft forgotten about) component here when considering drawing these sorts of analogies! ...But of course Dave, I know that YOU knew that. After all what would a Rotor-Wing Aircraft be (more than a ROCK) without POWER! ...And don't go giving me any of that typical chopper-pilot BS about how you can auto-rotate this, and autorotate that out of almost ANY situation either, okay?

Blues,
-Grant

coitus non circum - Moab Stone

[billvon 2,991]

> Pulling higher wasn't my plan and given I was being followed out by
>other Skydivers would this be an acceptable option or is it better to stick
>to the plan and accept landing off?

Generally pulling _slightly_ higher is OK. But don't change the plan by more than 1000 feet or so; people will not expect such a significant change.

>Secondly as the canopy got tipped by a gust to one side on landing is
> there anyway of dealing with this?

Turn your canopy back. Your canopy turns by tilting itself; if it tilts left it's going to turn you left. If you are landing crosswind and the wind is coming from your right, flare and turn into the wind as you are landing. This is called a flare turn, and is invaluable in such situations.

[diablopilot 2]

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The important point here is that canopies are not capable of a sideslip because they lack a rudder.

Untrue.


BTW have you seen the B2? Can't find a rudder on that.

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You're not as good as you think you are. Seriously.

[Hooknswoop 19]

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BTW have you seen the B2? Can't find a rudder on that.

Differential power from the engines outboad of the centerline is used to act as a rudder.

Ever seen pics of a B-52 landing or taking off in a crosswind? All of the wheels turn to allow the wheels to be pointed down the centerline with the aircraft crabbing into the wind.

Also check out vectored thrust like the X-31.

Derek

[diablopilot 2]

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Differential power from the engines outboad of the centerline is used to act as a rudder.

The B2 and previous flying wings are capable of non-banked turns even without using differential power.

One way to produce a short sideslip with a canopy is through use of the "pendulum effect"

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You're not as good as you think you are. Seriously.

[Hooknswoop 19]

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The B2 and previous flying wings are capable of non-banked turns even without using differential power.

How?, without flaperons(which canopies also don't have)?

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One way to produce a short sideslip with a canopy is through use of the "pendulum effect"

How?

Derek

[kelpdiver 2]

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As it was gusty I prepared for a PLF and as the canopy got hit by a gust and tipped downwind (as I flared) I successfully executed a PLF and came out unscathed.

That is the classic crosswind flare oops. As you flare you begin to realize you are drifting across the ground with the crosswind. You reach out with your downwind hand, a natural human reaction, causing the canopy to turn downwind. Jumpers blame a gust of wind when this happens. This is the opposite reaction necessary to land corretly in a crosswind. Adding in upwind toggle more than downwind toggle will flare turn the canopy into the wind, helping to counter the crosswind component and lean your body into the wind.

Derek

That sounds like a description of my worst landing, but I believe I touched down with the motion fully 90 degrees to my right. How does that happen - suggests I didn't turn so much as get blown over. Did the beginning of the turn drop that side enough to make it a luffy sail, coupled with near zero foward speed?

It was quite a PLF too! Nice helmet!

[Hooknswoop 19]

Once you touch down in a crosswind, the canopy is being anchored to the ground, and being blown to your side by the wind.

Same thing happens when you land into the wind, but with the canopy being blown behind you which is easier to pull/balance against.

Derek

[kelpdiver 2]

I hadn't touched down yet. In addition to misreading the wind line, I flared a few feet high.

I think. Definitely would have been good to have video because it quite a sequence, very fast. I want to hold on to the gust theory! LOL.

[Hooknswoop 19]

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I hadn't touched down yet. In addition to misreading the wind line, I flared a few feet high.

When you finish your flare, your airspeed drops to either zero or close to it. If your feet are not on the ground, your groundspeed will be equal to and in the same direction as the wind, like a hot air balloon. As you sink from the high flare you will hit the ground with vertical and horizontal (in the direction the wind is blowing) speed. This makes for a very 'difficult' landing since you can deal with vertical or horizontal speed by PLR or sliding/running respectively, but not both.

Derek

[Scrumpot 1]

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One way to produce a short sideslip with a canopy is through use of the "pendulum effect".

Careful JP. I'd really hesitate in quantifying that in a forum about crosswind LANDINGS. Performing this too close to the ground would be BAD JU-JU indeed, as think of your body position relative to the canopy, and then the ground as you approach the "apex" of that pendulum. ...See where I am going? -OUCH!

I don't think these lowbies need to think this is a viable alternative for them in this thread or context being considered. Further, when doing this manuever it also REQUIRES that you have significant further downwind "fly-out" room (and need to KNOW ALL components of what we are taling about here ...maybe even *I* do not know fully what I am talking about here ) to FINISH your resultant input flight-path. Using this as a "touch-down" technique regardless, IMHO opinion would be a mistake. -No?

-Grant

coitus non circum - Moab Stone

[pilotdave 0]

Ugh. B-2's have independent yaw control. Rudder, spoilerons, etc... canopies don't have any independent yaw control. I'm sure you can get a canopy oscillating in a way that'll get it sideslipping for a finite period of time, but it cannot maintain a sideslip indefinitely like a plane can.

Now, how do I sign up for YOUR canopy course where I can learn to do it?!

And scrumpot, I don't agree that power is required to sideslip. Sailplanes can slip for crosswind landings too.

Dave

[MarkFoster 0]

It seems like a few points were missed (unless I missed them in the threads)...

First, wind direction, exclusive of gust/sheer, has nothing to do with canopy performance. Period. It is only relevant to path over the ground.

Second, assuming the landing zone is not as narrow as a runway, a carving turn from crosswind across the ground can mitigate the restrictions that an aircraft has requiring cross-controls (slip) to maintain heading on the runway. Under canopy you can have a curved landing.

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...if ignorance is bliss, I'm in Nirvana... you don't know what you don't know 'til you don't know it.

GravityGone

[jumperconway 0]

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to clarify;
If you want to land straight you must put NW input (more left toggle). In full flight you have more penetration, as you flare the crabing effect get's exaggerated hence making you go more east than full flight.

Well,
After being bitch slapped by Derik that I am a dumb ass about aerodynamics and need to take a class on canopy control because I jump a high performance canopy(over 1500 jumps) and don't understand how a canopy functions let me correct what I wrote.

What I meant is what I wrote above. I am no engineer and wish not to purport is this;
Given the perameters of the original poster. The relative wind is obviously in front of the canopy(I do f#cking understand how a canopy works, Derik), What I weant was the corresponding element of the offending crosswind will push the canopy with the offending wind as the canopy slows and loses penetration further in that direction and to land in a straight direction that you have to give more input into the wind. If you beg to to differ then we will have to agree to dissagree. The chance of injury I would believe go's way up when trying to land going sideways versus landing straight in!
I will never jump your 60 but do understand canopy flight and was trying to help a newbie.

[Hooknswoop 19]

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In full flight you have more penetration, as you flare the crabing effect get's exaggerated hence making you go more east than full flight.

Not true. If the crosswind component is 5 knots from the jumper right, the canopy's airspeed is irreverent. The canopy will be drifting across the ground to the jumper's left at 5 knots. This drift does not increase as the jumper flares to slow the canopy. The jumper can flare turn the canopy into the crosswind decreasing or even eliminating the drift. Newer jumper tend to demonstrate this when they flare unevenly in no wind.

Derek

[jumperconway 0]

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In full flight you have more penetration, as you flare the crabing effect get's exaggerated hence making you go more east than full flight.

Not true. If the crosswind component is 5 knots from the jumper right, the canopy's airspeed is irreverent. The canopy will be drifting across the ground to the jumper's left at 5 knots. This drift does not increase as the jumper flares to slow the canopy. The jumper can flare turn the canopy into the crosswind decreasing or even eliminating the drift. Newer jumper tend to demonstrate this when they flare unevenly in no wind.

Derek

Derik,
If you would look above you have agreed with me. The crosswind is coming from the west or left! Exactly what I have said to flare more into the wind to cancel the wind drift and land safely straight in! See the above chart.

[Hooknswoop 19]

As you flare the "crabing effect" does not get "exaggerated". It is there as long as the crosswind is there and slowing the canopy down does not affect it.

Derek (with two "e"'s)

[jumperconway 0]

The canopy will be drifting across the ground to the jumper's left at 5 knots. This drift does not increase as the jumper flares to slow the canopy. The jumper can flare turn the canopy into the crosswind decreasing or even eliminating the drift.

I am not an engineer but know that your penetration as you fly crosswind is greatly effected if you go into brakes. Flying in full flight you will cancel some of the effect. 50% forward 50% sideways. As You flare and slow down you will approach 100% sideways!

[Hooknswoop 19]

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I am not an engineer but know that your penetration as you fly crosswind is greatly effected if you go into brakes. Flying in full flight you will cancel some of the effect. 50% forward 50% sideways. As You flare and slow down you will approach 100% sideways!Crazy

That means that if you are moving at 15 knots foward (50%) and 15 knots sideways (50%), when you flare
(to zero foward) you would be moving 30 knots sideways(100%). It doesn't work that way.

If you flare to zero foward the 15 knots sideways is not affected and you are still moving the same 15 knots sideways. The crabbing effect does not get exaggerated. If the crosswind component is a steady 15 knots, it will remain a steady 15 knots as the canopy is flared.

Derek

[jumperconway 0]

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I am not an engineer but know that your penetration as you fly crosswind is greatly effected if you go into brakes. Flying in full flight you will cancel some of the effect. 50% forward 50% sideways. As You flare and slow down you will approach 100% sideways!Crazy

That means that if you are moving at 15 knots foward (50%) and 15 knots sideways (50%), when you flare
(to zero foward) you would be moving 30 knots sideways(100%). It doesn't work that way.

If you flare to zero foward the 15 knots sideways is not affected and you are still moving the same 15 knots sideways. The crabbing effect does not get exaggerated. If the crosswind component is a steady 15 knots, it will remain a steady 15 knots as the canopy is flared.

Derek

then you've taken the canopy drive completely out off the equation. I don't think so. I would believe a 10 mph wind, downwind= +10mph groundspeed. Crosswind+5mph crossswind. This not a baloon.

[algboy 0]

"The important point here is that canopies are not capable of a sideslip because they lack a rudder. You can't fly a canopy with one "wing" low without turning. Roll and yaw are highly coupled"

This idea is more "intuitive" than scientific--I have to admit--but what if the jumper leaned into the wind with harness shift and countered with opposite toggle [or vice-versa]?? Could this create a crab? I don't have enough time under canopy to know, though.

[When a student pilot, I remember that I could bank into the wind and counter with a bit of opposite rudder to accomplish this]

The "not reaching" concept works--for me, at least. [I may have even read it on this BB] Anyway, my one real cross-wind landing went well because I DID resist the urge to "reach out" and held down a little extra upwind toggle during my flare. Just a little side-step when I landed.

“Keep your elbow up!"

[billvon 2,991]

>If you flare to zero foward the 15 knots sideways is not affected and
>you are still moving the same 15 knots sideways. The crabbing effect
>does not get exaggerated.

Actually it does.

Imagine you are landing to the north with a west crosswind. Canopy speed is 15kts, wind speed is 15kts. Your ground track (i.e. the direction you will have to run after you land) is northeast at 21kts.

Now you flare and get your canopy's speed to near zero. You are still moving 15kts to the east. Your ground track, however, has changed from northeast to east. People often perceive this as an increase in crab. It can be offset by flaring and turning into the wind.