skydiving w/ base canopy

[skydvr18]

Wannabe here. I just got a new base canopy and container. I want to put the canopy in a skydiving rig and make a few hop 'n pops before making a BASE jump with it (to know its flight characteristics, work on accuracy, etc.). I just need some recommendations. How should I pack it...a skydiving pack job, for a slower opening, or a BASE pack job? Should I put it in a D-bag? What size pc should I use? Mesh or sail slider? What kind of brake setting should I use? All recommendations would be greatly appreciated.

Blue Skies,
Josh

[guest]

Whenever I do that, I just stuff it in a skydiving rig and pack it like a skydiving canopy. I use a deployment bag, and all the standard skydiving accessories (pilot chute, bridle, etc). I typically use a sail slider and the shallow brake setting.

However, if you want to use those jumps as a more extensive BASE training exercise, you could freepack (BASE pack job) the canopy with a mesh slider. This would give you a better feel for how a terminal BASE opening feels (hard!), which will probably be better preparation for your first slider down jump (or big tower).

For saving wear and tear on yourself and your gear, though (especially if you're making quite a few jumps), I'd just go with the standard skydiving setup.

--Tom Aiello
tbaiello@ucdavis.edu

[guest]

I've only done this once (newbie too). We did a skydiving pack job, used a d-bag, but kept the mesh slider config versus sail. Crammed a Fox 245 in a Vector rig, I think. Skydiving pilot chute. Shallow brakes, though I do not think that would make too much opening difference in this situation.

Did a hop and pop from 13k. And I really did the "hopandPOP," as in had the PC out while I could still see the eyes of folks in the door of the plane.

Opening was mellow, actually, I was worried about a big smack from the sail slider, but the d-bag must've really slowed down the deployment. I've had harder openings from the Triathlon 160 I normally jump, much harder.

Then a LONG ride down with lots of time to play the stall and deep brake handling of my new canopy. As a newbie, it really helped my confidence to know how the thing landed and flew in a calm setting before BASEing it. Plus I got to take in a beautiful sunset on the long ride down.

My gut tells me that doing a freepack, mesh slider, and going anywhere near terminal without a d-bag would be a majorly painful experience. I mean, really painful. I'd not do it myself, even if it helped my BASE training. If I'm going to go terminal on a long BASE, I'd rather pack appropriately and not get massively whacked from a fast opening config. Then again, what the heck do I know?

Ciao,

d-dog
ddog@wrinko.com

[guest]

[font size="1" color="#FF0000"]LAST EDITED ON Aug-01-01 AT 01:44 PM (PST)[/font][p]Hey d-dog:

>My gut tells me that doing a freepack,
>mesh slider, and going anywhere near
>terminal without a d-bag would be a
>majorly painful experience. I mean,
>really painful. I'd not do it myself,
>even if it helped my BASE training. If
>I'm going to go terminal on a long
>BASE, I'd rather pack appropriately
>and not get massively whacked from a
>fast opening config.

Perhaps I misunderstand, but this seems to imply that you would use a sail slider on a terminal BASE jump.

While there are some BASE jumpers who use sail sliders on terminal objects, I feel that it is superior to use a mesh slider, even at terminal (and my impression has been that the majority of experienced jumpers concur with this practice). (Perhaps we ought to start another thread to discuss this? )

At any rate, as this applies to the original question, Josh may want to consider how he will pack for terminal with regard to deciding how he will pack for a skydive.

--Tom Aiello
tbaiello@ucdavis.edu

[squirrel]

I have an old skydiving container.. that does not have a D-Bag, so I jump it freepacked. 2 things of interest:

1. I rubber band the slider to the c-lines with 2 to 3 wraps. this has made a difference.

2. I was jumping out of a cessena, the old accuracy guys were recommending a 3-second delay. They claimed that you actually lose speed during the 1st 3 seconds of freefall (exit speed from the aircraft). It was hard to not deploy right off the step, but a 3 second delay opening shock was MUCH less than a true hop-n-pop. I also ask the pilot for a near stall jump run. I'm figuring your exit speed is even faster if your jumping from a turbine aircraft (faster jump run speed)

If you get really daring, you can route your brake lines outside of the slider and the keepers, that way you can learn how the canopy flies differently on a slider down jump. just be prepared to chop if you have a slider that doesn't want to come down (shouldn't if it's mesh... mine still slammed) I've only skydived this way twice, seems too prone for a line over.

Enjoy

Joe

[guest]

Ummmmmm. I'm not one to argue with people who been there - done that when I've not, but are they saying that as you leave the strut on a cessna flying at say, 85 knots (or whatever it may be), your airspeed is going to slow from 85 to 65 or something?
I'm no physics expert, as I'm sure the rest of this post will demonstrate, but if I recall from high school, your speed would have two vectors, one forward (from the airplane) and one down (from gravity). Your resultant speed is simply the sum of the two, I think.
It would seem to me, therefore, that if your airspeed were to slow down, your forward speed would have to bleed off faster (due to drag)than your downward speed increases (due to gravity). This does not seem realistic to me.
However, someone please correct my physics or my misunderstanding of what the CRW folks were saying.
If they say you have a softer opening after 3 seconds, I'll believe it, but maybe what they're feeling is the result of some quirk of the airflow off the plane?
Idaknow....

Since terminal is around 120mph, and most jump ships fly jump run less than that (even my friendly local king air), I don't think it's a 727 decelerate to terminal kind of phenom either...

Someone please make me smarter....

[squirrel]

alright, I'm an engineer and you mentioned vectors... so hold on.

The Force slowing you down is:

Drag = Cd * rho * (V^2)/2 * A

or more importantly, the drag on your body is proportional to the square of your velocity. i.e. your car has 4 times as much drag on it when you speed up from 30 to 60 mph. (not just twice as much as you might expect)

so, after your first second of freefall, you are only going around 10 mph in the vertical direction, but that 1st second is when you slow down horizontally the most. So even though you are speeding up in the vertical direction, you are slowing down MUCH faster in the horizontal (throw something out your car window going 80 mph, it looks like it stops with respect to your car, that's how fast it slows down)

did that confuse you or help???

[guest]

no, the car thing was a good analogy. Was I at least right about the basic physics (i.e. the sum of the two vectors equaling the total speed)?

It kinda flys in the face of what I always thought about exit dynamics.

Does this have any bearing on why my roommates chihuahua never gets hurt when I kick it over the fence? Are you saying I have to go REALLY REALLY fast in my car when I drop it out the window?

[guest]

Okay, all the freefall speed stuff is cool, but the real issue here is how to configure for this jump. I'm a relatively low timer but this is a fairly straightforward question. I feel he should freepack, mesh slider, skydiving P.C., but NOT route the control lines outside the slider. We want to simulate opening/ steering/ landind a BASE canopy, but I think the whole control line outside the slider thing isn't worth risking that malfunction. The mesh slider is fine for terminal openings...right??? I think so. I wouldn't use a sail slider for a terminal BASE jump. Sure the opening may be a little harder but that's the reality of BASE right? I don't mean to question your knowledge but I just want to analyze my own logic. How did you guys learn to fly a BASE canopy? Mine was off bridges with safe, open landing areas. I think that's what I would suggest. But I also think the canopy drills at www.crmojo.com would help our friend for now. What do you guys think??

[guest]

I've done a number of a/c exits with my base canopy in a large skydiving rig to check out my mesh slider-up packjobs, and canopy response etc.
I used no deployment bag, a mesh slider, 9ft bridle and skydiving pilot-chute (32"). The 9ft bridle was to reduce the risk of a pc hesitation, and give a realistic impression of the opening speed. I did a base pack job, with an extra fold to fit into the tray.
I tried this configuration on anything from 3 to 10 second delays with positive openings (but not painful) as a result. I didn't see it as any different than going terminal off a big wall.

Go as Real as you can...

[guest]

Still concerned with routing the control lines outside the slider grommets......

[squirrel]

Here's the story regarding routing the lines outside of the slider.

On my 1st slider down jump, I got myself into trouble with accuracy, I was surprised at how differently the canopy responded and flew. I wanted to mimic those flight charecteristics at the DZ. My intention was to route the brake lines through the slider, but not the keepers on the risers. Then after opening, I would reach up, and one by one push the toggles back through the slider and I would be able to fly the canopy as if it were a slider down jump.

My other reason for wanting to do this was to prepare for if I ever blew out a toggle. The rule that I'm waiting to implement is that if you lose a toggle, don't throw the other one (allows the canopy to deform too much) but fly with one toggle, one riser. My DZ is in wide open farm country so I figured I could purposly drop a toggle and pratice flying and landing in that scenario.

So before I did any of this, I checked with the safety officer at the DZ. He had no problem with it, so when I jumped, I realized that my old crappy container that I got that would barely fit my 265, was too large, and I sat so low in the harness, that I couldn't reach up far enough to actually push the toggles back through the slider. So I landed and when asked how it went, I told them I sat too low. Two riggers there who knew what I was trying to do suggested just packing the slider up, with the brake lines outside of the slider. according to them, with a mesh slider, it shouldn't stick up, and you probably won't get a malfunction (note the word probably). So I did it twice, never did drop the toggle.

One of the riggers said he had a 3-riser set up that were popular for high performance elipticals. I haven't jumped that setup, but he said it would allow you to fly the canopy very similar to what we experience on slider down jumps. Does that make sense to anyone?

-Joe

[guest]

I think that using a three riser set up is probably a safer way to simulate the flight characteristics of a line mod BASE set up.

If you route the control lines outside the rings, but through the slider, you risk a blown toggle entangling the slider and wrapping it in the pack job (nasty high speed streamer--aka screaming malfunction).

If you route the control lines outside both the slider and keeper rings (probably safer) you are creating a wildly inconsistent opening (without the primary downward drive of the control lines, the slider will deploy very slowly), with all it's attendant risks,

Of the two, I'd take the second option (outside both). But given a wider selection, I'd opt for the three riser setup. In fact, since I'm not real comfortable with that second parachute thingy on my back, I'd probably opt out of either of these choices, and just learn to fly slider down off a big bridge with a good landing area (go and throws from the highest bridge you can find ought to be good).

This might be one of the few areas where it's safer to take it straight to the BASE environment, without trying to skydive (with a questionable gear setup) first.

--Tom Aiello
tbaiello@ucdavis.edu

[guest]

That's the best advice I've heard all day! I've also found the hard way that the resistance from your steering lines is a major part of your slider coming down.

[d-dog]

No, I'm not sure I would use a sail on a terminal jump - mesh works fine for me. What I was trying to say is that I'd not personally want to take a slider DOWN pack near terminal. Those puppys open fast and they hurt, at least to poor little me they feel like they hurt when I have waited more than a second or so.

I forgot to mention the rubber band of my mesh slider (2 or 3 turns), which as another poster said probably slowed down the deployment alot on my hop and pop. Still, someday I'll do another without a d-bag and see how much difference the bag made, versus the other stuff (slider, rubber band, nose tuck, etc.).

FWIW, I jumped a slider up mesh on 5.5 second delay from a 850 foot object last night. Opening hurt less than my typical opening at the DZ, and I had a good canopy over my head in, I think, less than 150 feet. Seems ideal to me.

I also want to strongly second others experience that flying a canopy with the line mod versus without seems VERY different to me. My first two landings on the line mod setup have been pretty hard - the canopy handles differently, and flares differently. Not better or worse, just really different. If I could, I'd love to fly a hop and pop with line mod and really learn how to fly that canopy in this config - it is like a different canopy, at least to me.

Last night I flew it without the line mod for the first time on a BASE, and I was like *phew* now THAT is the canopy I thought I bought. Turned and flared just like I remembered from the hop and pop.

Live and learn!

D-dog
ddog@wrinko.com