Basejumper.com - archive

I found a 120' S with an all sand landing area. No obstacles. Heading performance is a non-issue as you could land straight in regardless of your heading...

D-bag or TARD? I've heard of 140' SL jumps, but 120 seems too low. How long would the expected canopy ride last?

Yes I've done a search...no I don't plan on solo'ing the thing tonight or anything...just looking for input.

HydroGuy --

First and foremost, I have not made jumps lower than 170ft. But over the years, I've studied the ultra-low jumps of others...mainly jumps and observations made by Base 587 and crwper. There are lots of folks that have made jumps under 150ft, but I consider these guys to be really experienced at these types of altitudes.

It goes without saying that a vented/valved canopy is absolutely superior for a jump this low.

At 120ft, I doubt that you will have time to release your toggles and generate enough forward speed for an effective flare. If I remember correctly, BASE 587 said that 130-135ft seems to be the minimum height he needs for an effective flare (with toggles). So I imagine that at 120ft, your probably better off leaving your brakes stowed.

At 120ft, the wind (and its direction) is very important. No wind, or a slight headwind is best. A tailwind will thump you in, and a strong tailwind will thump you in really hard. You'll need to pay close attention if there to the wind...

Your launch, and subsequent body position, is equally important. On jumps this low, it is best to exit "straight down", and not out. You also want to exit really head high. This will allow you to be directly under the canopy during bottom-skin expansion, with no pendulum effects. This will set you up for the landing better than if you were to launch out. (launching out causes the canopy to swing forward and if your body position is too flat, your body will pendulum upon opening) This will also keep your legs exactly where they need to be -- under your body and ready to be the first point of contact with the ground.

Their are physical limitations too. With jumps this low, are you prepared to take a substantial impact with a good PLF? Folks that are light-weight, in shape, and limber are able to take a hit better than someone who is fat, out-of-shape, and old.

Also keep in mind that 587 and crwper have taken their time and worked their way progressively lower and lower. They might make it look easy, but they have taken many steps to get there. (just as you are taking proactive steps and gathering as much information as you can)

Hope this helps,

Bryan

P.S. in answer to your original question, a Direct Bag deployment will open faster than a static-line. It is possible to static-line at 120' (see above). I think it is debatable on whether or not a TARD is faster than a direct-bad deployment. A very well executed Tard might be faster...but it has to be executed perfectly.

well, I dont have much experience with tards or Dbags, but why not SL it? useing a useing a Big pilot chute, even if the SL failed, you should* have enough altitude to walk away with a sand LZ...


freefall it!!!

 
For A while I've had an idea in my head for a low altitude D-bag. Where the canopy would pack in a longer bag more like a sleave. Whith the center cell already fully spread. Imagion takeing a normal pack job and spreading the line groups and center cell to width. It would now look basicly like a U. S fold the bottom half of the U in thirds to shorten it like a reserve pack leaveing the ears above with out narrowing. The bag would be a large square with a square sewn down in the upper middle between the ears. Probable easiest to spit the sides to aid packing. The flap would be a trapazoid that would come up high enough to close the whole mouth and fassen with two rubber bands with a tail pocket above it. For carry it would fold in thirds but at the exit you would fold the sides out and clip the two corners so that it would be spread.
I've never been in to the low stuff. And I'm not advocateing this I have never gotten around to building one. The idea is utterly untested and consist of nothing more then the wind blown out of my ass. Just curious if any one has built a more specalized D-bag for really low oppenings?

Lee

I don't have too much to add here, as bps has pretty much covered it, I think. Nevertheless, I'll add my two cents.

First and foremost, this is something that you need to work down to. There are a few skills which need to be learned very well, and along the way you'll learn a lot about how conditions affect low jumps. 587 and I made about 50 jumps from 165' and 140' in one winter before jumping anything lower.

Oscillation is a very important factor in low-altitude static line. The two main ways you can induce oscillation are a hard launch and unstowing your toggles too aggressively. The key points in avoiding this are:

1) Learn to drop straight off the object. This should feel a lot like you're stepping off the curb. If you launch too hard, it puts your mass ahead of the canopy on opening. The canopy will surge forward to compensate, and you'll lose a lot of altitude in the process. If you drop straight off, this surge is minimized.

2) Learn to unstow your brakes in a controlled manner. If you unstow your brakes too quickly, the canopy will surge ahead and you'll lose altitude. If you unstow them too slowly, you'll lose altitude because you've spent too much time in deep brakes. The trick is to pull the toggles down in one quick stroke just to the point where they clear the white loop. Then let them up more slowly until you are in full flight. With practice, you will learn to feel how quickly you can let the brakes up.

I'm about 145 lb and fly a Fox 245 vtec. For me, 165' was a good altitude to practice these things from. Unless I am terribly careless about my launch and brake release, there is still plenty of time to fly after opening. In contrast, a friend of mine who flies a Troll 305 MDV, and loads it more heavily than I load my canopy, found the flight from 165' quite short. Once you've determined a comfortable static line altitude that gives you 10 seconds or so of canopy flight, practice the skills above. If possible, find a site where you can make multiple jumps in quick succession, and see how far you can fly from the object. This is a great way to dial things in.

Make plenty of jumps from that altitude. It's important to realize that if you go from 160 feet to 140 feet, you're not just cutting off 12.5% of your altitude. Your minimum static line altitude will (optimistically) be about 110 feet. So you're actually going from 50 feet above the minimum to 30. Think of it as a 40% reduction in your working altitude. For the same reason, if you've not already done so, invest in a good laser rangefinder.

If you can, try to find at least one object whose altitude is intermediate between your practice altitude and the 120' S. Make some jumps from it. You should be able to pop your toggles and fly a bit before you have to flare.

By this point, you'll have some idea whether or not 120' is even a good idea for you. Even with all the practice jumps, it's likely you won't know exactly what to expect when you do jump from 120'. As I said above, it's all about how high you are above your basement. You will never know exactly where the basement is, so try to keep a realistic idea of the error of your estimate. Changing conditions will also have an effect on the basement altitude.

Once you have an idea where your basement is, you'll be in a much better position to judge the safety of the jump you're looking at. Even at that, knowing that there is a margin of error on your estimate of the basement altitude, keep the following in mind:

1) You probably won't have time to unstow the toggles. Spend plenty of time practicing your PLF. Plan to PLF on the first jump, even if it looks like you might be able to unstow the toggles.

2) Pick a night with no wind. A tail wind will delay your opening slightly, and a headwind will cause you to drop straight down, which makes it much harder to do a good PLF. 587 and I found dramatic differences jumping with no wind, or with a 3 mph headwind.

3) Know how you will get your broken body out of the landing area if you have misjudged your basement altitude.

Well, that's about all I can type in one sitting. I hope I've managed to convey the importance of working down to that altitude, and give you some idea what to work on.

A d-bag will give you a bit more altitude, but is not a silver bullet. If you plan to d-bag the thing, you'll still want to spend plenty of time working on dead launches and good brake release technique. I prefer static line because of repeatability, but it does cost you a bit of altitude.

Hopefully 587 will chime in about the tard option, since I can't think of anyone more qualified. However, my general impression is that unless you have tremendous low-altitude tard experience, this would not be a good idea.

Have fun!

Michael

 
Do you keep track of the conditions when you jump? In perticular Density Altitude? What are you normally at on these jumps and can you quantify the effect of higher DA.

Lee

Don't have much else to add other than my own experience.

Jumped a ~120 bridge pylon over hard land. Not exactly sure on the height, but it was 105 rungs + twice my height to where the ladder begins. I was PCA'd first and the 2nd guy SL'ed himself. At the time I was around 145-150lbs and jumping a vented w/ covers Fox 245. Had shallow brake settings and unstowed immediately after pressurization. Canopy time was around the 5 second mark. There was no wind and I had a lot of forward speed on landing and had to run pretty hard out of the flare to stand it up. Flew ~100ft from the exit point. The 2nd guy landed a skydiving canopy without any center cell topskin. Being light and in shape is priceless in this sport.

I'd do it again without any reservation, especially since I've lost some weight and dropped a canopy size.

I (too) cannot comment pretty much other things than my own experiences. We jumped 38m cliff (124ft) PCA'd last winter over solid ice. We used unvented canopies (Mojo and Troll) and had canopy rides of about 4-5s, there would have been time to pop the toggles but we both decided to land using rears. I did a PLF and my mate landed on his feet. Both were using deep brake settings and conditions were pretty much calm with no wind at all. I'd say it was still pretty reasonable and I'm looking forward on doing it again this winter with my vented Troll to see if there is significant difference in canopy ride. Still, I'd say it has pretty small margin for error so if you decide to give it a go, be sure to have somebody you really trust as your PCA'er. Have fun and don't bounce.

And of course... If it's not on video it didn't happen... :) So here's the video http://www.cs.helsinki.fi/...i/talvimeininkia.wmv

My only other comment is how you configure the static line. I'm a heavier jumper (for my low jumps (around 140ft) i jump a troll dw 305 and that's slightly loaded btw).

If you tie off to the pilot chute attachment point that means you have a minimum of 9ft to fall before the pins are even popped. If however you use a shorter bridle (specific) or simply larkshead a loop into your 9ft bridle a few feet from the bottom pin/shrivel flap and attach the breakcord to that, the whole deployment is going to happen sooner. 7ft sooner perhaps and that is a big gain on a jump of 120ft.

Similarly, a well executed short bridle PCA would be an option. The buddy holds the bridle close to the container and initiates deployment almost the moment your feet leave the edge, only releasing the pilot chute when you reach line stretch.

Bigger canopies have longer suspension lines so will open lower. Not a lot lower, but lower. Heavier jumpers will pound in harder.

ian

What about brake settings? If there's little chance of object strike and you think you may be flaring on the risers with the brakes still stowed is there any value in using a shallower setting?

Gus

Great post.

What I tried to do for ultra low altitude was:
- unstow VERY symmetrically and attempt to get the brakes close to the stowed break setting as quickly and safely as possible. i.e. your brake line stow (brake setting) would be near your loop on the riser. The reason is to keep your canopy aerofoil the same. As crwper says - then you can control your toggle input gradually to the ground. DON"T DO ANYTHING DRAMATIC. It is very important that you pull the toggles down in a controlled manner. If you drop one toggle and pull the other down, you will end up hooking it in and getting busted up pretty badly. A slight oscillation may give a similar outcome.

Someone I know (I can't say who it is because it may be interpreted as too egotistical) jumped from 31m (about 102 ft). The object was a span with water underneath that gradually reduced in depth leading to a sand bank. That person worked his/her altitude down from various objects (hundreds of very low jumps over several years). Then they did the 31m over water a number of times to test his/her reaction to control inputs and test the inflation and flight characteristics of the canopy. The jump was made on a Pooster 210 with weight of approximately 200 lbs. The final jump was made on a number of occasions over about 3 feet of water using modified s/l. The canopy was reasonable well inflated (although it was still oscillating a little), a slight s turn was made from the water towards the sandbank. The jumper stood up a landing in about 1 foot of water and the canopy fell dryly onto the sandbank.

I have to stress that there was the minutest margin for error on these jumps. One error and you'll end up broken up. Do not do it unless you have the experience that crwper is talking about and are prepared for the consequences.

The photo's attached show a s/l from 75 feet into water with a clapped out,short lined, x228 crw canopy. The other are two jumpers jumping from around 55 feet (need to check it). You'll notice that the jumper on the light coloured canopy has unstowed his/her brakes and has gained a marginal amout of altitude on the left jumper. You will also notice that on all photo's, if done over hard earth (or soft sand), there is not enough inflation and deceleration to save your arse. Don't do it over heard earth - if you want to live and walk!!!!

If your angle of attack is greater and your brake setting shallower, you will get more surge on opening. There are balances everywhere. Too deep and you will stall.

can only speak of myself
I would still SL the object,BUT READ THE ABOVE POSTS CAREFULY!!!

Only thing i can add is that on ultra low jumps i stow my brakes slightly shallow(yes i have settings for this),which makes my canopy fly,still really slowly, rather staying close to the stall point,that way its more easy to land i think(reariser,if time if not PLF)

Practice PLF ALOT!
Toptune your gear(spectra loops,brake settings etc etc)
USE BODY ARMOR!!
Practice
Practice
Practice

Michael,we need to hook up some day You guys have a 180ft waterfall that i missed on my latest trip,Spence know whih one. besides that im sure we could have fun in lowland

If it was me I'd go d-bag for two reasons:

1. Faster opening than SL

2. You can have your hands on the toggle from the get go.

lose weight. it's the safest way to ensure that you won't break any bones on a terribly hard landing.

sounds like a bad idea to me...

I rather land on rearisers than unintentionly pop a brake while deploying(wrong word i know,but dunno the right word) my canopy..

460,your right but then again if it really goes bad the big boys will be stronger and more posible survive(well thats my excuse)

an abandoned limestone quarry near mi casa has an 88ft shelf that has seen plenty of drunk carnage over the years. plenty of "county diver recoveries". personally jumped it once. my ankle hit me in the face and broke my nose pretty good. of course this was all with no nylon and 80' deep water below.
that shit feels like concrete i swear.

If I could offer up a refinement on that... Body weight in fat does little to protect a person in the event of a hard landing, adds the stress of extra mass to muscles and bones absorbing the impact, and in the case of severe injury hinders surgeons trying to get to the important stuff. I had surgeons and nurses comment on that last one following my only major injury.

On the other hand, muscular body weight helps absorb impacts not only in the obvious way, but also in that the tissue itself absorbs direct impacts before that energy can get to bones and internal organs. Even a skinny bastard like me can put on enough muscle to make a difference.

Lastly, I've come to see physical fitness as sort of an insurance policy. The fitter you are before an eventful landing, the fitter you'll be immediately after. Maybe that means you fail to break anything. Maybe that means you live.

Really? Didn't you break your leg pretty badly playing with risers. I don't want to rub it in but please do not adventise what has not worked for you.

Given the choice toggles are always your best bet. Of course there is a proper way for popping the toggles without having the canopy surge and dive to the ground.

skinny little John Hoover, BASE 95, broke through a window on a 180 building strike, landed on a guys desk, got dragged back out by turbulent winds with the canopy hanging outside the building, hit the building twice, and made a crash landing on a 2 story building, tied his canopy lines onto the top of the 2 story buidling, skimmied down the lines, and ran away, essentially uninjured. being thin (yes, I could stand to lose about 20 pounds but my work requires chronic long term sitting) is really required for any extreme endeavor. it is especially useful for doing aerials. body control really suffers from any extra weight. that and it really adds to the safety margin when weight is low and the body is rubbery childlike. even a little extra weight stresses the joints heavily and can cause terrible injuries.

well you dont rub it in my face,yes i did make a rearriser stall and broke my ankel pretty bad,BUT

Practice makes a master.. I now has no problem landing on rearrisers only regret i has is that i didnt learnt before i started BASE jumping..

I think that flying on your toogles on ultra low jumps the chance of getting a forward surge while popping brakes is bigger than stalling out the canopy..

I GUESS you dont have much experience on lowdeployment and therefore rearriser landings,they should(if you want to play in the low area) be as good as toogles..My bad were at the point were i had my incedent NEVER had tryed rearriser landings(my incedent actualy also were a high pull off 600ft,blown toogle,i had plenty of time,but used it wrongly)

and dont tell people about stuff you dont have all facts about..

I had one insedent whith rearriser landings,i havnt counted as of yet but my guess is that i so far has 40-50ish rearriser landings from BASE,whith no further incedents..

Now go figure why i think its a better option even as i once(at my jump #30)broke my ankel..

Blue Skies 460,

HydroGuy is under 6 feet and thin.

I don't keep track of everything, but almost all of my static line jumps are in winter, with temperatures around -10 Celsius. The 111' span is at an elevation of about 3500' ASL; the 165' and 140' jumps are at about 2500' ASL. Most of my s/l jumps are from the latter object. Unfortunately, because there isn't much variation in the conditions I've jumped it in, I can't really quantify the effect of temperature/barometric changes.


I've usually used shallow brake settings on s/l jumps. This seems to reduce surge when the brakes are released. It's a bit of a balance, though, since a too-shallow setting will result in a lot of surge before the brakes are released. Too-deep will put the canopy closer to a stall on opening, and encourage a surge after the brakes are released.

Michael

How many sub 150 d-bag jumps do you have?

with all due respect i disagree. hydroguy is one the phattest men i've ever met.
in all seriousness does anybody have tips on the TARDing side of the coin?

lady and men

today is fight night.

on one hand is faber, man with big heart but quick with rifle if rub wrong way.
on other hand is base_rigger. is he a he, is she a she, is he a heshe or she a shehe. nobody knows but tonight maybe mask come off.

we bring you this entertain for free

enjoy!

While this method may work for you, I think this is bad advice. Having your hands in the toggles during your deployment seems like a recipe for a premature toggle release. This could be really bad on a 120ft jump. Of course, this is just my opinion.

Just wanted to throw that out there for others to think about...

Bryan

PM BASE 587. He's probably the best TARD jumper I know, as well as the person who's done the lowest TARDs. I think he's got all 4 objects under 150 ft.

Borat,

I just got this 3 way maggot, you, and I can do from 120'. What ya say?

you say:

Borat,
I just got this 3 way maggot, you, and I can do from 120'. What ya say?

I reply:

i thank you very much for offer.
when i am going to new york i will like very much.
is it ok if i go stoed and be low man? i need lot of speed because my old russian parachute take to long to open otherwise. i have also big 42 pilot chute. we can be fun.

That's be cool. You might also want to jump on your back so you can take a good video of maggot and me. Maggot is extremely photogenic.

0 i didnt tell people how to do d-bag jumps through

oh well you have the biggest balls anyway,i dont really care im not gay so keep them to yourself...

I'm also very curious about the TARD vs SL debate. There's a ~135ish indoor jump in my neighborhood that I'm looking foreward to one day
Which would be a better choice?

see earlier posts that discuss the skills YOU need to develop.

I'm sure once you develop these skills, you will be able to make an intelligent choice. remember, it is YOUR call.

It depends if an on-heading opening would be preferable for this jump?

That's sad.

There is a great book out there called "Zen and the lost art of d-bagging" a must read for any jumper who got in the sport in the last 15 years.

Hummm d-bagging...

i'd rather watch tv than db. - Rick Payne, BASE 137

I feel the same about S/L!

DB has come a long way since its origin. Modern d-bags are state-of-the-art cutting-edge work of rigging at its finest without a doubt and then you always get that feeling thinking your mate might be holding it wrong, got to love it.

i'd rather db than be at the dz. Alan Hetherington.