Rear risers V Brakes glide chart

[freeflyer2k 0]

Hey
I saw a chart somewhere that detailed glide distance for a particular canopy on rears and on brakes in various upwind and downwind situations in various wind speeds.

I cannot find it anywhere now...
anybody got a link or a copy?

BTW im not starting another rears v toggles debate here its just the chart as i remember it would be handy for giving students an example of how things vary depending on conditions and that hard and fast rules conventions don't always hold true

Blues
Mike

It was the worst day of Icarus's life but for everybody else it was just another damned hot day in Greece

"When the only tool you have is a hammer, everything looks like a nail"

[d123 1]

Maybe is not what you are looking for but PARIS wing from paraflite has some graphs for toggle input on different WL too.

http://paraflite.com/PARIS_ImageGallery.htm

Don't know how much you can count on those graphs. Half year ago I've asked the PD guys if they have similar graphs for NAV200 and they answer me that the AIR GLIDE can change up to 15% from jump to jump, hour to hour and so on.

I still have the mail somewhere.

Lock, Dock and Two Smoking Barrelrolls!

[freeflyer2k 0]

Thanks
but thats not the chart i remember.
the one i am looking for detailed distances traveled on fronts, rears and in full flight compared against head and tail winds of various speeds.


Blues
Mike

"When the only tool you have is a hammer, everything looks like a nail"

[Spizzzarko 0]

I do not think that you will find one as there are to many variables to encompase in such a chart. You need to take in Temp, humidity, DA, wind, canopy size, canopy type, porosity of material, size of lines, wing loading, jumper body position, brake line shrinkage, & line length to name a very few of the variables. An aircraft operating manual will have a few charts on take off and landing distances but even then there are many assumptions that are figured in on those charts and sometimes they are not as accurate as you would think.

You can figure glide ratio of about 2.5:1 on smaller canopies (if you are a good pilot). From there you could extrapolate speed from distance and time. After you figure in the upper level winds you might be able to figure out some of the variables, but finding out upper level winds would be expensive as you would need to fly at least a triangular pattern at every altitude and figure out the wind speed by averaging your ground speed against airspeed. That is expensive to do as it would take awhile and most DZO's do not want to spend that amount of money in fuel or hot section time. The NWS forcast for winds aloft is just a forcast and is usally wrong. So now do you see that what you are asking for is a rather nebulous subject and would encompase to many variables to even approach being accurate?
If you do find your chart please post it as I would like to see it.

[Pendragon 1]

... but what is it you want to know?

Some things never change:

Max glide is always faster than min sink, even in a strong tailwind (although the greater the tailwind, the closer max glide is to min sink)

Double fronts only induces a stall part way across the wing, reducing the efficiency and increasing descent rate. In a strong headwind whereby you'd be going backwards otherwise, double fronts can get you down quicker, thereby reducing the time you're being blown backwards by the uppers, thereby improving your glide.

Brakes deform the wing at the back, so you decrease the sink rate but degrade the glide

Pulling your knees up improves the glide ...

etc
etc

--
BASE #1182
Muff #3573
PFI #52; UK WSI #13

[freeflyer2k 0]

Like i said guys
I dont want to start another debate thread.
the chart referenced one particular canopy...
I want it in order to underline to canopy piloting students... (not swoopers) that hard and fast rules do not always apply and that they need to explore and learn the performance envelope of their individual canopies for themselves...

I have been searching like crazy for this chart and im beginning to hope i didn't dream seeing it

Blues
MIKE

"When the only tool you have is a hammer, everything looks like a nail"

[jheadley 0]

There are rough graphs like this in The Parachute and It's Pilot that show how each input affects your glide in different wind conditions.

[freeflyer2k 0]

this is close to what i was after
http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=790180;search_string=glide%20distance;guest=42591290#790180

"When the only tool you have is a hammer, everything looks like a nail"

[Spizzzarko 0]

http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=790180;search_string=glide%20distance;guest=42591290#790180


Here I am doing Ian's job for him. I'll just go ahead and tell Sangiro to fire him as he is slacking. Ian's probably out in his red shirt at the local Atlanta gay kareoke bar, singing:

"I know what boys want"
"I know what guys like"
"Boy's like...."
"Boy's like...."
"Boy's like Me."

[ianmdrennan 2]

Actually it was more like

"Y"
"M"
"C"
"A"

Performance Designs Factory Team

[dharma1976 0]

were you wearing the construction guy outfit or the "Native American"???

or maybe the cop...

D

http://www.skyjunky.com

CSpenceFLY - I can't believe the number of people willing to bet their life on someone else doing the right thing.

[Spizzzarko 0]

Either way, his mustace is fake.

[swOOOPS 0]

I remember the chart you are talking about and I believe PD maybe put it out (not sure) But I do remember it and I believe best results come from full flight into the wind and brakes' set for going downwind

[Spizzzarko 0]

"best results come from full flight into the wind and brakes' set for going downwind"

Now you don't hear that very often around here do you? PSych!!!!

[igoswoop 0]

Scott Miller devotes a pretty substantial portion of his Essential Skills Canopy Courses to this particular issue. The only way to find out is to check for yourself. Everyone's configuration is a little different and every nature born variable comes into play when it boils down to it. It's hard to drill in the fact or fiction that "this" works better than "that".... Better to let people choose after experimenting for themselves and go with what works. Grant hit many of those variables and they ALL will play their part in each instance.

If you don't get back you should've pulled higher...

[kallend 1,620]

Quote

.

Pulling your knees up improves the glide ...

In all situations? Can you prove it?

...

The only sure way to survive a canopy collision is not to have one.

[Pendragon 1]

"... in a headwind" is what I should have added (to make yourself 'smaller' and reduce drag)

--
BASE #1182
Muff #3573
PFI #52; UK WSI #13

[adamT 0]

I what situation can you imagine where reducing the drag on the bottom half of the system will reduce you glide.
adam

[DrewEckhardt 0]

Quote

I what situation can you imagine where reducing the drag on the bottom half of the system will reduce you glide.
adam

Less drag underneath reduces the trim-angle especially at higher airspeeds. Shalower trim reduces airspeed. When the larger forward component of the velocity vector doesn't offset the speed decrease effective glide ratio drops when you don't have a tail wind resulting in range inreases due to the added time in flight.

[adamT 0]

So you are saying that in a headwind situation it will reduce your forward speed and ultimately reduce you glide.

I would argue from experience, both way up high and on the ground swooping and ground launching, that a reduction in drag always increases your glide. Im talking about a configuration that is settled not one that is still bleeding off energy from a high speed maneuver. I think that even though you flatten out the glide you maintain speed due to the lower drag. I get plenty of hands on experience with this flying down hills after foot launching or exiting a plane. Big lazy legs hands all the way up, sink down on the hill. Tight body position, lean forward, legs tucked up behind, arching. Fly away from the hill.

I out run people on my way back to the dz all th time. People with the same size wings, bigger wings, head wind tail wind, strong light. Body position has a lot to do with it. And the goal is to always have as little of you in the wind as possible.
adam

[kallend 1,620]

Quote

"... in a headwind" is what I should have added (to make yourself 'smaller' and reduce drag)

Depends on the canopy and its trim. It ALWAYS helps running downwind, but into a strong headwind it can be counterproductive on a canopy trimmed for a flat glide. Easily proved.

...

The only sure way to survive a canopy collision is not to have one.

[kallend 1,620]

Quote

So you are saying that in a headwind situation it will reduce your forward speed and ultimately reduce you glide.

I would argue from experience, both way up high and on the ground swooping and ground launching, that a reduction in drag always increases your glide. Im talking about a configuration that is settled not one that is still bleeding off energy from a high speed maneuver. I think that even though you flatten out the glide you maintain speed due to the lower drag. I get plenty of hands on experience with this flying down hills after foot launching or exiting a plane. Big lazy legs hands all the way up, sink down on the hill. Tight body position, lean forward, legs tucked up behind, arching. Fly away from the hill.

I out run people on my way back to the dz all th time. People with the same size wings, bigger wings, head wind tail wind, strong light. Body position has a lot to do with it. And the goal is to always have as little of you in the wind as possible.
adam

Drew is correct, but it does depend on the canopy. Even when it does work the effect is small (most of the drag of the system comes from the canopy, not the skydiver).

...

The only sure way to survive a canopy collision is not to have one.

[adamT 0]

Belive me the effect is not small. This is tested time and time again. At wingloadings from 1.3 to 2.6. I challenge you to go fly any canopy next another canopy of simillar loading and design. Get level and beside them. Have them fly big legs and dearched. Now you arch hard and tuck your legs behind you. You will begin to out fly them both in float and forward drive. The effect is much more noticable with smaller canopies at high loadings, but it is there on the big ones too.

[kallend 1,620]

Quote

Belive me the effect is not small. This is tested time and time again. At wingloadings from 1.3 to 2.6. I challenge you to go fly any canopy next another canopy of simillar loading and design. Get level and beside them. Have them fly big legs and dearched. Now you arch hard and tuck your legs behind you. You will begin to out fly them both in float and forward drive. The effect is much more noticable with smaller canopies at high loadings, but it is there on the big ones too.

But if you float in a headwind, you stay longer in the adverse winds. THAT is the problem with canopies trimmed for a slow, flat glide, and why the effect on overall range in a headwind is less than most people believe. In the extreme (headwind so strong that you're going backwards) more float will put you even farther back.

In a tailwind, the float has a beneficial effect on range.

...

The only sure way to survive a canopy collision is not to have one.

[adamT 0]

But when combined with better forward drive you will be penetrating more and making more forward progress. Foot launching stiletos(very flat trim) in winds so strong that you are pretty much paragliding(able to stay aloft as long as you want), the only way to move forward is to fly a efficient body position.