Wing loading

[garyharbird 0]

I have 2 velocity 84s which i ordered last winter.
When i ordered them i weighed 145 giving me a wing loading of 2.0, during the winter i joined the gym and gained 20 lbs and now fly with a wing loading of 2.3.
I work fulltime as a cameraman, and i am really enjoying the canopies, getting back from long spots has not been a problem.

I was wondering what wing loading people are flying?
And at what wing loading you start to sacrifice distance for speed ?

Thanks guys

Gary Harbird

[Steel 0]

for the past 6 months I have been at 3.4. I believe pretty strongly that for a 27 chamber you will start to sacrafice distance for speed at about 2.8 or 2.9. I don't have as firm an opinion on 21 chambers but I am guessing 2.5 or 2.6. Don't get me wrong I don't deny the fact that Clint Clawson had the 340 foot record with a 2.2/2.1 wingloading but I don't believe he would have gone less distance if he was doing 2.5 instead. As for Shannon's 418 foot swoop, GET REAL it was downwind. I don't believe current canopy technology can break a 400 feet with no wind.

If I could make a wish, I think I'd pass.
Can't think of anything I need
No cigarettes, no sleep, no light, no sound.
Nothing to eat, no books to read.

[diablopilot 2]

I fly 27 Xaos canopies at 2.25 and 2.39 and the performance of the larger one (93sq) is better. IMO the performance drops off as you fly over 2.2ish. Recently put a few jumps on the same type of canopy loaded at 2.9ish, and the performance was way down, all that was left was raw airspeed.

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

[quade 4]

Quote

And at what wing loading you start to sacrifice distance for speed ?

In theory that doesn't happen at all. Again, in theory your glide ratio doens't change with wingloading, but your speed down the glide slope does.

If you jumped a Mythical 120 loaded at 1:1, it would have the exact same glide ratio (horizontal distace covered:vertical distace lost) as the same Mythical 120 loaded at 2:1. It would be traveling down the glide slope MUCH faster however. Again, this is the theory and based on the front surface area drag of the canopy (wetted area) not changing.

In practice, what happens is slightly different and, in fact, as you go to smaller and smaller canopies the glide ratio does change because you're changing the scale of the wing and changing the wetted area in a non-linear way. Also the wetted area of the wing changes, but the wetted area of YOU does not.

As for specifics about at what point the wing is at maximum efficiency in terms of wing loading, that would differ from canopy model to canopy model and even within the same canopy model it would change significantly from a relatively large canopy to a small one.

All of that said, piloting technique is probably more important in terms of getting back from a long spot than any wing loading change you're likely to have encountered due to a small weight gain.

quade -
The World's Most Boring Skydiver

[Watcher 0]

The Factory Team Sits around 2.0-2.2 lb/ft2. I would put money that they feel that is the optimal loading for a Velocity. (considering they get to have any size they want that makes sense).

--

Jonathan Bartlett
D-24876
AFF-I

[andy2 0]

[QUOTE]The Factory Team Sits around 2.0-2.2 lb/ft2. I would put money that they feel that is the optimal loading for a Velocity. (considering they get to have any size they want that makes sense).
[/QUOTE]

So why do you see people with 2.6, 2.7, 2.8? Is this purely for the speed factor? Do they admit that they are sacrificing distance? I guess not everyone's goal is distance. Is it generally accepted ~2.2 lb/ft2 is optimum for distance? What is optimum for speed then?

---------------------------------------------
let my inspiration flow,
in token rhyme suggesting rhythm...

[Yoshi 0]

Quote

guess not everyone's goal is distance. Is it generally accepted ~2.2 lb/ft2 is optimum for distance? What is optimum for speed then?

no canopy out is best for speed:)
2.2 on a crossfire 2 isnt optimum. 1.85 is... 2.2 may be opti on a crossbraced canopy... depends on the type of canopy...
-yoshi

_________________________________________
this space for rent.

[Steel 0]

You couldn't have said it better. NOT EVERYBODY"S GOAL IS DISTANCE. It has gotten to the point where I just want to smack the idiot with 500 jumps who stands in front of me and says I don't know why you keep going smaller your not getting anymore distance. (almost like they think they discovered America) The only thing that crossses my mind is how this person with canopy skills that are noticeablely beneath mine thinks he can possibly teach me something. I know my wingloading is not optimal for distance. But even with that totally inefficient for distance wing I am still swooping further than the majority of these people giving free advice. You can go out and see what J.C. and Clint are flying and then you can go out and buy the same loading and canopy style but if you can't dive your canopy like they could (consistently), I am still going to out swoop you, even in distance which is not my goal to begin with.

If I could make a wish, I think I'd pass.
Can't think of anything I need
No cigarettes, no sleep, no light, no sound.
Nothing to eat, no books to read.

[AggieDave 6]

Quote

The only thing that crossses my mind is how this person with canopy skills that are noticeablely beneath mine thinks he can possibly teach me something

I tend to look at it this way. Everyone, no matter what experience they may have, can probably teach me atleast one thing. I've had students with 10 jumps talk to me, they pull something out that I hadn't thought of before, it makes sense and proves true, I just learned something new from someone with very little experience.

My point is that you never know what someone might be able to give you, so don't shut them off automatically.

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[Ron 10]

Quote

So why do you see people with 2.6, 2.7, 2.8? Is this purely for the speed factor? Do they admit that they
are sacrificing distance? I guess not everyone's goal is distance. Is it generally accepted ~2.2 lb/ft2 is
optimum for distance? What is optimum for speed then?

Answer...Cool penis points.

"No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334

[BMFin 0]

So, at swooping contests, a lot of people will fly bigger canopys than they normally do ?

[quade 4]

Quote

NOT EVERYBODY"S GOAL IS DISTANCE.

I believe the original question, the point of this enitre thread, revolved around distance -- and not distance in a swoop either -- glide distance, as in making it back from a long spot.

quade -
The World's Most Boring Skydiver

[Steel 0]

well then I guess I read it wrong. But hey if you want a great glide ratio what you need is a para glider. No parachute could even come close but since you can't deploy that at terminal what you need is a huge canopy. Bigger will pretty much glide further and it will take a really big chute before you get to the point where its actually too big and just collapses.

If I could make a wish, I think I'd pass.
Can't think of anything I need
No cigarettes, no sleep, no light, no sound.
Nothing to eat, no books to read.

[BMFin 0]

Quote

You couldn't have said it better. NOT EVERYBODY"S GOAL IS DISTANCE.

Would you / Do you fly a bigger canopy when attending a swoop contest.

[SkymonkeyONE 4]

Pretty much everyone on tour upsized last year to get better distance. For speed, most just pile on more weights. The larger wing weighed down to a heavier wingload has been found to work best for this purpose.

Chuck

[Steel 0]

I don't compete but if I did it would depend on the competition. For a speed round requiring that I run a 220 course I probably would fly my VX-70 because with a well flown approach it will take me the required 220 foot without problem and it will be faster than most others (or atleast I think it will). To be competitive in distance I would need a new canopy, probably a VX 84 or 89. A VX-84 or and 89 would probably make the accuracy course (what really should be called a carving course) a lot easier to score high on. Keep in mind the sizes are not absolute for all. I am just talking about what I think would be ideal for my body weight. Now if they put out the competition that I would want to see that is they put a radar gun out there and clocked your speed while going through a set of wind blades then I would go with whatever my smallest canopy at the time was. (now a vx-62)

If I could make a wish, I think I'd pass.
Can't think of anything I need
No cigarettes, no sleep, no light, no sound.
Nothing to eat, no books to read.

[andy2 0]

^^^ do you mind translating what a 70, 84, etc is WLed for you? Just curious...

---------------------------------------------
let my inspiration flow,
in token rhyme suggesting rhythm...

[Steel 0]

for me
62 = 3.4
70 = 3.1
84 = 2.6
89 = 2.47

If I could make a wish, I think I'd pass.
Can't think of anything I need
No cigarettes, no sleep, no light, no sound.
Nothing to eat, no books to read.

[crazy 0]

Quote

In theory that doesn't happen at all. Again, in theory your glide ratio doens't change with wingloading, but your speed down the glide slope does.

Apparently, he was asking about the length of the swoop. As i got bored, i took a few minutes to figure out what the theory would say about this. If i didn't screw up (didn't spent too much time to validate the theory), in an ideal world, the length of the swoop is proportional to the inverse of the area of the canopy. A 50 sqft swoops twice longer than a 100sqft. A 10sqft swoops 10 times longer than a 100sqft.

My hypothesis:
- the lift coefficient is proportional to the angle of attack (Cl = l a)
- the drag coefficient has a constant component and a component proportional to the square of the angle of attack (Cd = d0 + d2 a^2)
- the coefficients l, d0, d2 are a characteristic of the type of the canopy and are independant of the size
- there is no drag from the pilot and the lines
- all the canopies start swooping at the same angle of attack and they all stall at the same angle of attack

I spare you the equations. The important point is that the coefficient of drag has a component proportional to the square of the angle of attack. This quadratic component is a real killer as soon as the angle of attack is a bit bigger than the optimum, particularly at the beginning of the swoop. It might significantly contribute to explain why most people see the length of their swoops decrease when the wingloading (the speed and responsivity) increases above a given threshold.

--
Come
Skydive Asia

[D22369 0]

WOW........could you demonstate the "skygawd" mentality any better??? any person with a different perspective has something to add to any discussion........so they have less jumps than you do so what?? maybe they thought of something you didnt............. ok he man, flame away

Roy R. Springer
D22369

They say I suffer from insanity.... But I actually enjoy it.

[Ron 10]

Problem is that the pilot, and the lines do not scale with the canopy.

Plus higher wingloaded canopies of the same type have a higher stall speed.

I have found that once you go too small the distance of the swoop stays close to the same..however the speed is faster.

But I don't have any cool math stuff to back it up.

Ron

"No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334

[Steel 0]

Don't misunderstand me I don't believe jump numbers are a tell all. Hell I know more than a dozen people with 3 times as many jumps as me and I definately do not think they know more than me because of that. But when somebody has just 500 jumps it does sound like they started last year or the year before. Although I think I caught on fast, when I had five hundred jumps, I could not tell you what an ideal wing-loading for speed, distance or accuracy was, how differently a canopy would react to harness input at different wingloadings, what a rear-riser landing felt like on a wide variety of different canopies. So my point is that when that when the newbies (people jumping less than 3 years or with less than 500 jumps) tell me something that sounds like they are repeating somebody else's words, it gets annoying after a while. All I can think is why don't you just take a tape recorder and record the person you heard say that and then come and play if for me again. Because I know for sure that you certainly don't have the required experience to make that assessment for yourself.

If I could make a wish, I think I'd pass.
Can't think of anything I need
No cigarettes, no sleep, no light, no sound.
Nothing to eat, no books to read.

[SkymonkeyONE 4]

I have jumped several different canopies down to the point of reaching diminishing returns. While I regularly safely landed them, I found them to be more trouble than they were worth as far as both personal satisfaction and measured distance and controllability were concerned. Each canopy type reacts differently to lower and higher wingloads. I will state two examples:

-I used to jump Atair mains and had access to some pretty cool prototypes in different sizes. I regularly jumped the "same" canopy in sizes 85,75,and 65. I ended up settling on the middle size for 99 percent of my jumping. The 65 was neat and fast, but the front riser usable control range was so short, the riser pressure higher, the stall speed so much higher, and my measured swoop distance so much shorter that it stopped being worth my time to jump. I sent it back so that others could play with it. The 75 in that canopy type was perfect for me.

Under my Velocities I have found that a slightly larger wing suits me better. I would have thought that my "standard" main would be my 75 and my "competition" main would be my 79. Odd how much difference four square feet can affect performance and "feel", but in this case I decided that I am much happier with the larger main in all cases and will probably get an 84 as my distance main.

One thing I can say for sure is this: you will get consistently better measurable results under a canopy that is easier for you to fly. True, you may occasionally get better swoops out of a "faster" or more "high tech" main if you throw a perfect turn, but the second you blow your setup even a tiny little bit, you are better off with that more manageable main. When I owned both a VX-74 and an Alpha 84, I could, on average, in a "regular" jump day, get sweeter turns out of the Alpha. In no-traffic, no-wind, "clinical" instances when there were no students and lock-neck syndrome fun jumpers flying around over our HP airspace, I could then get a longer swoop out of my VX. I ended up selling it because I hated the openings and we had too much traffic here for me to enjoy it.

Chuck

[grega 0]

Quote

IThe 65 was neat and fast, but the front riser usable control range was so short.

could you define what that "front riser usable control range" means.
i've tried to find out if there is possible to pull front riser to much to be effective. if you pull both front risers too much, you make sort of a stairstep in canopies shape, and that's not good well at least not efficient.
But i never got to find out if single front riser can be pulled to much. i mean pulling it that much that it's not efficient any more.
So can you please explain what means front riser usable control range.

"George just lucky i guess!"

[SkymonkeyONE 4]

Here is the exact comparison: On both my Competiton Cobalt 75 and H-Mod 75, I would throw my turn at a set altitude by pulling my right front riser clear to my chest. This caused a steep, controlable, diving turn which went around fairly slow. All my turns, with very few exceptions, take four seconds to complete. Anyway, on the 65, from the exact same altitude, If I pulled the right front riser more than about four inches, it would spin on an axis considerably faster than it was diving. I could, literally, throw a 540 on that 65 from the same altitude I did my 270 from under my 75. You couldn't just honk down on a riser and snap it around. To get the perfect four second turn under that canopy was very difficult. That is one of the primary reasons I stuck to my 75. It dove much longer and steeper.

Chuck