Can wingloading be too light?

[Orange1 0]

Yes, I'll ask my instructors, but just wanted to get some opinions here too. 2 main questions.

I'm going to start looking around for a canopy soon, and a 150 at my exit weight will give me a wingloading of less than 1. (I'm using 22lb here for rig weight as a rule of thumb, but am not sure how much a sq foot of parachute material weighs so it may be less?) Are there any problems associated with too low wingloading eg if I get a 190 or 210 will it be a problem? I'm very light on my student canopy but also know that these behave better. And if I am used to a wingloading of around 0.5 will a sudden move to say 0.9 or 1 be difficult to handle?

Second, at some stage I presume I'll want to go above 1. Do smaller sizes (say 120 which would give me 1.2 based on same exit weight calc above) come in 'normal' squares or are they mainly elliptical?

Thanks

Skydiving: wasting fossil fuels just for fun.

[sid 1]

You got it right about checking with your instructors, but, that said, yes a parachute can be loaded too lightly for optimum performance. However, the type of canopy usually recommended for a novice or student performs fine when lightly loaded. We are talking of designs like a PD 9 cell, a PD Spectre, a Jump Shack Mentor. These canopies are designed with a large control range and perform fine when loaded through that range.

Ask, demo, be safe (hey that's a good motto)

Pete Draper,

Just because my life plan is written on the back of a Hooter's Napkin, it's still a life plan.... right?

[mr2mk1g 10]

Be sure to discuss with your instructors how a 120 canopy loaded to 1 does not behave the same as a 190 canopy laoded to 1. Thats an important difference that many people overlook.

[Orange1 0]

A kind lurker PM'd me this weblink. I post it here because it seems to answer all my questions as well as the issue re different size canopies flying differently at the same wingloadings. It's by Scott Miller. Maybe will help some other newbies.

http://www.performancedesigns.com/docs/choosing1.pdf

Skydiving: wasting fossil fuels just for fun.

[meltdown 0]

Be aware also that a very light wing loading makes it difficult to get any penetration in windy conditions. I'm not saying go jump in high winds, but you could find yourself in a bad situation if the winds pickup and you find yourself flying backwards. If you are used to .5 WL, you will definately notice a difference at .9 or so. I'm still loading at about .97, and it's quick enough for me at 240 jumps. However, if the winds are about 18 mph, I get very little penetration into the wind.

[pilotdave 0]

My personal record is about 0.45 on a Manta 288. A 190 or 210 isn't excessively large. Most of my student jumps were on 230s, with the exception of my first jump, which was on a 170, and a couple jumps on that manta when i visited another DZ. I definitely had my share of backwards landings under the 230s.

What have you been jumping so far?

Dave

[Orange1 0]

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What have you been jumping so far?

a 280! i like it cos i've stood up no-wind landings
Meltdown - i'm not really planning on jumping in windy conditions, for a long time anyway - i'm a pretty risk-averse jumper. (my whuffo friends think this is a contradiction in terms.)

Skydiving: wasting fossil fuels just for fun.

[billvon 2,998]

> Are there any problems associated with too low wingloading eg if I get a
>190 or 210 will it be a problem?

Depends on the canopy type. PD does not recommend loading below .5 on any of its canopies. I have found that Stilettos become dangerous below about .9, but most canopies are fine down to .75 or so.

>And if I am used to a wingloading of around 0.5 will a sudden move to
>say 0.9 or 1 be difficult to handle?

Probably not - as long as you get good instruction on what the differences will be.

>Second, at some stage I presume I'll want to go above 1. Do smaller
> sizes (say 120 which would give me 1.2 based on same exit weight
>calc above) come in 'normal' squares or are they mainly elliptical?

Yes. You can get a Sabre 1 97 if you want, which is a true square.

[ryoder 1,590]

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I have found that Stilettos become dangerous below about .9, .

Can you elaborate on this?

"There are only three things of value: younger women, faster airplanes, and bigger crocodiles" - Arthur Jones.

[ryoder 1,590]

My personal rule-of-thumb:

IF you are jumping in winds that do not exceed the recommendations for your experience level, AND you are backing up when you face into the wind, THEN your loading is too light.

This situation makes it difficult to predict and control where you land, thereby making the situation more dangerous than if you were on a more heavily loaded canopy.

"There are only three things of value: younger women, faster airplanes, and bigger crocodiles" - Arthur Jones.

[billvon 2,998]

>Can you elaborate on this?

I once jumped a Stiletto 190 loaded a little over .9 to 1, and it felt about like my old Nova did in turbulence. I suspect that since it is trimmed quite flat, lighter loadings do not produce sufficient airspeed to keep it as stable as a more steeply trimmed canopy.

[wmw999 2,452]

I wouldn't even go that far. If you don't mind landing backwards, then go ahead. Anyone who jumped in the round days has done this, only landing harder than you do under a square.

I agree, though, that if the canopy requires a certain amount of airspeed to maintain stability it needs enough loading to be safe.

Wendy W.

There is nothing more dangerous than breaking a basic safety rule and getting away with it. It removes fear of the consequences and builds false confidence. (tbrown)

[GravityGirl 0]

Yup, yup. When we used to fly Manta 288s for ALL students, I watched a students canopy fold in half about 50 feet off the deck. I have that on video. She was about 115 lbs. It was freeky to say the least. It reinflated for her just in time for me to say, "Flare, flare, flare."

Icky.

~~~~~~~~~~~~~~~~~
Peace and Blue Skies!
Bonnie ==>Gravity Gear!

[DancingFlame 0]

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Be aware also that a very light wing loading makes it difficult to get any penetration in windy conditions

There's one more thing about this. Smaller canopies have better penetration than equally loaded bigger ones. Canopy planform and affects penetration as well.

[skybytch 273]

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IF you are jumping in winds that do not exceed the recommendations for your experience level, AND you are backing up when you face into the wind, THEN your loading is too light.

I have a D license. I can jump in unlimited winds according to the BSR's. I would be backing up under my current canopy in winds over about 20mph. Is my wingloading too light?

No, my wingloading is just fine for my ability and level of risk tolerance. Once students go on wind hold, so do I... and I don't find myself backing up on final.