Question regarding downsizing

[quade 3]

Yeah, something like that.

The really high-priced Kestral wind indicators also do a lot of other functions as well. I'll have to find a proper link here in a minute or two.

HERE we go.

The one I'd really want costs about $330.

It'd be possible to get about the same data using the $90 model, but having one that would automatically store other atmospheric data would make things a lot easier.

quade -
The World's Most Boring Skydiver

[franck102 0]

Michele, rather than trying to plan your approach (if the wind is x then at y feet I'll turn for my base leg) I would recommend that you choose a pattern (e.g. downwind - cross-wind - final), know roughly when & where to enter it, then learn to adapt it in real time to land where you want.
This includes comparing your ground speed in the downwind leg to your previous landings - this tells you how much wind there is, if you're screaming along you'll want to turn cross-wind a bit earlier that usual. n the cross-wind leg try to actually follow a line on the ground that is 90 degree to the wind - how much you need to point your canopy into the wind to do that will also tell you how much wind there is.
On that same cross-wind leg look where you would land if you kept going straight until you land. If it's 400' away you know if you turned into the wind right now you would land somewhere between 400' (no wind) and 0' (wind = your canopy's forward speed) from your turn. If you keep doing this and factor the wind you'll know at any instant how you should adapt your pattern.
The reason why a predefined plan (with turning points & heights) doesn't work too well is that our canopies forward speeds are very close to the speed of the winds we fly in. The consequence is that a minor difference in wind speed will dramatically affect your glide ratio with respect to the ground, which is what matters as far as your approach is concerned. This is not just perception, a large canopy with the greatest glide ratio in the world can fall straight down in a 15 mph head wind (ground glide ratio = 0), while a small canopy would still make progress.
Franck

[franck102 0]

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Michele --
If the ONLY thing you were to do was to change the wingloading, then although the decent rate and forward speed would be both increase, the actual glide ratio would remain almost exactly the same.

True in theory, although in practice if you downsize significantly on a given canopy design you glide ratio will deteriorate significantly as well. That is because the drag of your body remains the same and affects the smaller canopy more, the lightly loaded fabric of the large canopy will match the intended airfoil section better, and the smaller canopy will have more induced drag (same air molecules for both...).
Just trying to add my two cents to the good-reasons-not-to-downsize pool... smaller canopies don't glide as well as larger ones -)

[quade 3]

Well, yes, but there is also a little less parasitic drag on a smaller canopy due to the shorter line lengths and surface friction on the canopy due to it's smaller surface area.

I'm NOT saying it would be a wash, but I bet it's not as significant as most people think.

quade -
The World's Most Boring Skydiver

[Michele 1]

I'm far too stupid to understand most of these answers. But thanks for trying. At this point, I suspect that my confidence has been eroded enough for me to reconsider skydiving altogether. I wish I had the wherewithal to actually jump more, to take the canopy class more than once, to buy several canopies, and to not have to rent equipment. That's not the way it is. And the way things are going, it's not the way things are gonna be for a long time. Therefore, my option is to keep my feet firmly planted on terra firma.

Ciels and Pinks-
Michele

~Do Angels keep the dreams we seek
While our hearts lie bleeding?~

[AndyMan 7]

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I'm far too stupid to understand most of these answers. But thanks for trying. At this point, I suspect that my confidence has been eroded enough for me to reconsider skydiving altogether. I wish I had the wherewithal to actually jump more, to take the canopy class more than once, to buy several canopies, and to not have to rent equipment. That's not the way it is. And the way things are going, it's not the way things are gonna be for a long time. Therefore, my option is to keep my feet firmly planted on terra firma.

Michele, that doesn't sound like the person I know...

Nobody is saying you should buy a bunch of different canopies. None of us certainly did that, when we were looking for our first rig. You're lucky enough to have Square 1 right on your DZ who happens to have one of the best demo programs around. If you really feel it's important to jump a bunch of different canopies, then you can sign up for their demo program. I think that's overkill, though.

Landing a big ole' conservative canopy is easy, and even if ya biff in it doesn't hurt that much. If you can't afford to take the canopy course, don't. Most skydivers get by just fine without it.

This thread tells me that you're making the classic student mistake of thinking WAY too much about things... and I'm sure people's overly technical answers aren't helping. Billvon and Paul and even myself sometimes forget what the original question in the first place is... and I think that happened this time. Exactly which windmeter Paul buys so he can document exactly how each canopy flies doesn't help answer your question.

The fact is that there are no simple rules when flying a canopy - it's the same as driving a car. We don't come up with rules that say "if you're driving a chevy cavalier, and are doing 45 mph, you need to begin braking 100 feet before the stop sign". When to start braking in your car is just something that you figure out when you start driving. If you start late and have to brake harder, or start early and have to ease up, it don't amount to a hill o' beans. Flying your canopy is the same thing - exactly when you enter the pattern and at exactly what point you make your turns is something that you'll figure out pretty quickly once you start flying a new canopy, but it certainly isn't worth losing any sleep over.

Michele, go jump, don't downsize until you're perfectly comfortable with the one you're flying now, and when you do downsize, just go one size at a time so that the difference between canopies is small. If your DZ doesn't have these sizes of canopies available, I know that Square 1 does and trying them out doesn't cost much money at all.

_Am

__

You put the fun in "funnel" - craichead.

[Deuce 1]

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Therefore, my option is to keep my feet firmly planted on terra firma.

Michele, do you have a copy of the video of you jumping with me, Seb, Matt, TOM, Nathan, and Gary?

If you don't, I'll send you a dub.

If you don't jump, you don't get to smile like that.
If you don't jump, you don't get to have that look in your eye.
If you don't jump, you don't get to do "tippy-toe" landings and laugh at the sky as your canopy falls to the ground around you.

The guys on these forums have way, way more jumps than you and me. I'm still new, so maybe I remember being really really new more than some of the grizzled veterans.

On my AFF 1 I was amazed that I could remember to do three practice rip cord touches and look at my altimeter. I remember that after I landed I looked at my altimeter, but couldn't recall what altitude I was at.

Sensory overload. I'm still in it. Now while I'm flying my cameras, I do my best to fly, but there's lighting issues, artistic stuff, and remembering to take stills and get the customer to smile and thumbs up. Everybody can get better. There's always new stuff to learn.

When you've identified the pattern look at the ground when you're facing the wind. If the ground is coming toward you you'll land past it, if it's moving away, you'll land in front of it. Do some left and right turns to clear up that you're going to touch down in a wide, clear area. You're about 600 feet up. Find that spot on the ground that's not moving either toward you or away while taking deep cleansing breaths, check the horizon. When you're on the first floor balcony, start your flare.

Tippy toe the landing, or PLF. And do it again.

It's fun.

[franck102 0]

Michelle, you don't need to know sh*t about glide ratios, rate of descent or any other fancy technical stuff to have great landings, those things are only only useful to fuel long arguments on the ground around a beer.
You know how to land your current canopy, going down one size won't make any difference and you'll adapt just fine. Just go for it!
Franck

[quade 3]

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You know how to land your current canopy, going down one size won't make any difference and you'll adapt just fine.

Actually, she's still just learning and is not very current.

I would prefer for her to jump a couple weekends in a row on the canopy she's currently using before downsizing. I think that's the general consensus of most of the folks that have worked with her as well.

That said, the more she understands about the basics of making landings and the effects her canopy decisions have on them, the better able she should be to apply that to her landings.. A little more knowledge of aerodynamics certainly isn't going to hurt and from my experience usually helps quite a bit.

quade -
The World's Most Boring Skydiver

[billvon 2,400]

>At this point, I suspect that my confidence has been eroded
>enough for me to reconsider skydiving altogether.

The confidence (and the skill) will come with time. There are plenty of people who learn at different rates - I know some people with thousands of jumps who aren't good canopy pilots, and compensate by using larger canopies and being more careful about conditions they jump under.

As to quitting skydiving - that's a decision only you can make. Is how you feel when you're up in the air worth the effort needed to get up there? From what I've seen of you after you jump, it seems to be, but only you know for sure. As long as you have the desire, your skills will eventually get there.

[quade 3]

Michele --

If I ever respond directly to one of your posts and you do not understand the answer I give you, please feel free to ask for clarification until you -do- understand what I'm saying.

However, understand that if I'm responding to say . . . Bill Von . . . then I probably will sometimes write in essoteric terms that I know he will be able to understand. ALWAYS feel free to ask what the hell we're talking about. I will always try to make it comprehensible to whatever level of understanding -you- currently have.

From what I've seen, your problem isn't one of your understanding the material anyway -- it's a matter of coming out and putting it to meaningful practice.

quade -
The World's Most Boring Skydiver

[franck102 0]

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Well, yes, but there is also a little less parasitic drag on a smaller canopy due to the shorter line lengths and surface friction on the canopy due to it's smaller surface area.
I'm NOT saying it would be a wash, but I bet it's not as significant as most people think.

Actually drag on the lines is roughly proportional to surface x (speed squared), so even the shorter lines on the smaller canopy will generate much more drag - that's why microlines are more critical on a fast flying canopy.
Not too sure about the surface drag, but the same may apply...
Franck

[SBS 0]

I jump a Spectre 190 loaded at about 1.25:1

--------------

Wow...that would mean that you weigh...ah, nevermind...

:)

-S

_____________
I'm not conceited...I'm just realistic about my awesomeness...

[franck102 0]

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You know how to land your current canopy, going down one size won't make any difference and you'll adapt just fine.

Actually, she's still just learning and is not very current.
I would prefer for her to jump a couple weekends in a row on the canopy she's currently using before downsizing. I think that's the general consensus of most of the folks that have worked with her as well.

Ooops, sorry I forgot the obvious, take the advice of the people who have seen you fly over anything you read here!
Franck

[quade 3]

Franck --

Obviously you'd have to take all of the various drag components into the equation.

So, what you're suggesting is that any decrease in parasite drag due to scaling factors is off-set by the increase parasite drag caused by increase in airspeed required by the smaller canopy to maintain the same glide ratio. Remember that the increase in airspeed will also increase the lift and all we're really interested in here is L/Dmax anyway. Hmmm, interesting, I'm not certain it's a wash, but there's only one way to find out isn't there? Testing.

As stated before, it would be an interesting study to see how linearly the performance of canopies of the same type did scale, but besides just the pure scaling factors, you'd also have some small manufacturing issues. For instance, my guess is the packing tabs, line attachments and seams remain the same size throughout the entire line - perhaps making smaller canopies slightly less efficient. I -suspect- the manufacturing issues are probably more significant than the simple scaling of the wing, but obviously I have nothing to back that up.

What do you have in the way of hard data or are you just spouting theory like the rest of us?

quade -
The World's Most Boring Skydiver

[jfields 0]

Michele,

I understand about the explanations being complicated. Sometimes I glaze over trying to get through the aeronautical reason for something or other. But I do see that the greenies (and others) most often get into that when dealing with each other, and in response to complex questions.

You can skydive without knowing the details, although they do help some people.

Think of it like driving a stick-shift car. You can feel how the clutch works as you start a stop. You learn how to balance the clutch and the gas depending on how you want to shift and what surface you are on. After awhile, it is easy and intuitive. You can do that without knowing how many horsepower your engine gives, how much torque in first gear, the ratio of axle to tire size, or whatever else. You just *feel* it.

It just takes practice. My first bunch of landings went like this:

biff, biff, biff, biff, standing, biff, biff, biff, biff....

Then things got better as I got the hang of it. Now they are just about reversed, with the rare ungraceful landing amid the nice ones. The really ugly landings are getting more and more infrequent.

My landing patterns continue to get better as well. I time the legs of my pattern to put me where I want to go better than I did before. I've learned how to make adjustments for different factors as I go along. If I need to make up ground from my base leg to my final, I just sort of cut them short into a curve. It is all a gut-level intuitive thing you develop after practice.

You'll make the same transition. Just stick with it and jump. Try to learn without overanalyzing. I doubt even Paul or Bill do this while they jump:

My current descent rate is x feet per second, and the dropzone is y yards away, so with a windspeed of z miles per hour on a heading of q degrees, I need to begin my final approach precisely at the following point...

I bet they take note of the wind, and know their canopies, so just get into a zen-like state where they know, "Hmm. To land there, I need to do this." Then they just do it without having to really think about it. At least, that is my assumption. Take your time on the same canopy and work your way to that subconscious familiarity with your canopy before you downsize.

I bought used gear at jump 17, and I plan to be on the same stuff for hundreds more jumps, because I still have plenty to learn.

Good luck!

[franck102 0]

> I doubt even Paul or Bill do this while they jump:
> My current descent rate is x feet per second, and the dropzone is y yards away,
> so with windspeed of z miles per hour on a heading of q degrees, I need to begin
> my final approach precisely at the following point...

Right, I have no idea what the glide ratio of my current canopy is, and I can still land it anywhere I want.
> I bet they take note of the wind, and know their canopies, so just get into a
> zen-like state where they know, "Hmm. To land there, I need to do this."
Quite right, you just keep doing all that again every 10 seconds so you can adapt your plan.
Franck

[franck102 0]

> So, what you're suggesting is that any decrease in parasite drag due to scaling factors
> is off-set by the increase parasite drag caused by increase in airspeed required by the
> smaller canopy to maintain the same glide ratio.
Yes, based on the fact that drag increases linearly with the surface but with the square of the speed (approximatively of course).
> Remember that the increase in airspeed will also increase the lift
It will increase the coefficient of lift (lift / surface used to generate it) but not the actual lift of the flying canopy (will always be just what it takes to balance the suspended weight). The actual drag on the other hand will increase because of the speed, since even assuming you can keep the drag of the canopy constant the drag of the pilot will increase for sure, and most probably so will the drag of the lines.
> What do you have in the way of hard data or are you just spouting theory like the rest of us? I'd call it semi-hard data -) The above math, and a few years helping test new paragliders designs. The only reason to make them fly faster was always to make more ground against the wind, and we always ended up sacrificing some glide ratio in the process.
Another interesting data point comes from model gliders. Even though they don't have a fixed drag component (like the canopy pilot), it is well known that large models can achieve better glide ratios because they fly at larger Reynold numbers.
Franck

[weid14 0]

larger reynolds numbers? that's talking dirty if you're an engineer and into fluid mechanics....

[Michele 1]

Deuce

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Michele, do you have a copy of the video of you jumping with me, Seb, Matt, TOM, Nathan, and Gary?

No, I don't have a copy of it. If there is a way to get one, I'd appreciate it....

BillV, I do love jumping. You're right - but the look on my face afterwards comes nothing near how it makes me feel.

Quade:

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Actually, she's still just learning and is not very current.

I would prefer for her to jump a couple weekends in a row on the canopy she's currently using before downsizing. I think that's the general consensus of most of the folks that have worked with her as well.

As I would prefer to jump all weekend for several weekends in a row. However, the funds and the time are just not available right now. I work at least 6 days a week, on straight commission. The cost, if I jump 3x per day, 2x a weekend, is $249. If I did that two weekends in a row, that's $498. If I did that 3 weekends in a row, that's $737 (not including gas, food, and lodging). Add to that +/- $250 for the canopy class. And then add to that the lost work (as if it matters right now - nothing's happening no matter how hard I work), 6 days of prime work. That is, literally, more than half of my monthly budget.

As far as I recall, Lisa's jumped with me 3 times, and we've worked hard on the RW stuff I need to know, and it has made significant differences. You've worked with me one morning on canopy stuff and jumped with me once (I landed both jumps that day on my toes, perfectly, in case you don't recall), and made significant differences. John Brasher (hugs to you, John), sat with me, viking and Lummy for a morning, and did a great impromptu seminar on the ground about canopies. If you're counting the hateful, nasty PM's from parties unnamed about how horrible a jumper I am (but who don't offer any help, even when they're at the dz when I am...), then yes, perhaps there is a consensus. However, as you, John and Lisa are the only ones who've actually jumped with me, and have seen good and bad landings, who're the consensus? You make it sound as if there are 20 people sitting around, scoring me or something. If there is, please let me know. I'd like to bribe them or something....

Look. I am trying to put together a rig, so that I can jump more. Did anyone jump on Viking when he came from a 288 Manta to a 210 in one step? Did anyone tell him to take the canopy class? I am not talking about making a 78 foot jump in canopy size. I am talking about making a 20 foot jump - one single size, which I have jumped previously and landed successfully. As for the canopy control class, I have been told 2 very different things: one, "yes, of course we'll teach you with rental gear", and "no, you must have your own canopy, because we teach you to fly *your* canopy, and it won't be as effective if you switch right after". I can't buy two canopies. I don't know which is right. I'll bet that I can convince them that rental is fine, I need the class to downsize successfully, and I want very much to take the class. Irrespective of that, however, I just can't do it financially right now (gear rental + canopy control class is $314.00...and with nothing in escrow, who knows when my next check is coming?

And my original question wasn't about my downsizing, it was an observation about changes in setting up the landing pattern. Thanks to HooknSwoop, I understand something I didn't know before. And because he guuded my hand to the light switch, I can sort of understand what you guys are talking about.

But the bottom line remains. I have been informed, as Clay used to say, that "I am a danger to myself", I should not ever get in a plane again til I take the canopy class, and so forth. As if commentary like that helps with confidence. Which, I've been told, has everything to do with landing well.

Therefore, I am faced with a dilemma. No matter what I do, stay in the rental canopy or use my own, I still have to land. The only way to not have that occur is to NOT jump in the first place. So, the question is "to jump, or not to jump....."

I am very frustrated right now. Very. And for those to whom all aspects of jumping comes easily, treasure that. It is not coming easily for me.

Ciels and Pinks-
M

~Do Angels keep the dreams we seek
While our hearts lie bleeding?~

[Milo 0]

Just fly it, Michelle.

Talk to the folks at your DZ and see what they have to say, but don't stress out over it, the differences in flight characteristics for this change for you will not be as great as the variations in your own choices for every jump you have done so far.
Trust your training and you will do fine.
If you meet anyone at the DZ with a programmable calculator sticking out of their pocket, run like hell.

Just Jump!

Milo

[franck102 0]

Michele,
You can look at it this way: 3 mph more or less wind while under your current canopy will have a much more dramatic effect on your landing pattern than the change in size you are contemplating. If you can handle the wind variations (there is no way anyone can predict the wind that accurately), you can handle the downsize (just don't start with either extreme).
As far as listening to the people who see you fly, let's rephrase: just pick a few you trust, and ignore the others -)
My wife has about 15 canopy jumps total, and went from a 288 to a 220 to a 190 in 5 jumps (all F111, 135 exit weight) and didn't think twice about it - same approach, same flare technique.
Franck

[skybytch 259]

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If you can handle the wind variations (there is no way anyone can predict the wind that accurately), you can handle the downsize (just don't start with either extreme).

What if someone can't handle the wind variations - i.e. won't jump in no wind conditions on what they are currently jumping? Would you still tell them it's safe to downsize?

[franck102 0]

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What if someone can't handle the wind variations - i.e. won't jump in no wind conditions on what they are currently jumping? Would you still tell them it's safe to downsize?

I have no idea whether it's safe for them to downsise, I only know that on the specific problem of flying their landing pattern they could get in trouble the first time they jump the new canopy in light or no winds. On the other hand if they can fly their pattern in 0 wind with a small margin of safety they should have not trouble doing the same with a slightly smaller canopy.
There is more to downsizing safely than just flying the right pattern , see Bill Von's excellent post in another thread in this forum about all the things you should try before you consider to downsize.
Franck

[PhreeZone 15]

If there is too much speed on a low/0 wind day the jumper has to reconsider going smaller. In fact going larger might be an option until the jumper is comfortable landing with 0 wind or even down wind in 3-5mph winds again. If the jumper goes uncurrent on a large canopy, its a lot harder to stay safe on smaller gear.

Yesterday is history
And tomorrow is a mystery

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