Lost my Neptune, found my Neptune

[cpoxon 0]

Two weeks ago I was at Hibaldstow taking part in the awesome 28-way competition. I was wearing my 2k Composites FFC camera helmet (no longer made but similar to the side fx but with a flat spot on top for another camera. I got very excited after the fantastic fifth round jump and dropped my helmet in the landing area. What I didn't notice at the time was that my Protrack must have popped out of the elasticated netting audible holder that is inside the helmet underneath the padding. Due to the presence of the Skyvan and it requiring the grass runway to take off, everyone was landing in the farther larger lower experienced landing area. After being bussed back I packed up my rig. When I'd finished a call went out if anyone had lost a ProTrack. Mine is coloured very distinctively and I was easily able to identify by that and the number of jumps on it (thanks to Nick from Damn Zebra for finding it and handing it in). At this point I checked to see if my Neptune was still in my camera helmet, which to my dismay, it wasn't :-( I assumed it had bounced out at the same time as my Protrack. I scoured the landing area for a while, but to no avail and gave up looking. I notified the dropzone asking people to keep an eye out for it, hoping that the Neptune's waterproof natue would keep it safe until someone stumbled upon it.

Due to tandeming and BASE jumping, I didn't jump my sport rig last weekend. Fast forward to this weekend and after a day of tandeming I managed to hop on the sunset load and do a fun head-down jump with the Colonel from the Chekidowd gang. After landing, Mike on DZ control, was asking if anyone had lost a Neptune on the last load. I almost said, "yeah, me. Two weeks ago at Hibaldstow!" but didn't want to look stupid, so said nothing. It had landed next to a guy sitting outside is motor home, in the parking/camping area of the dropzone. He'd heard it falling and land 10 feet from him, picked it up and handed it in (thanks Ty!) My Neptune is a World Team one and is coloured a very disitinctive red, white and blue. There are a couple of other World Team members on my dropzone so Mike got routed back to me where he asked me if I was sure I hadn't lost anything and then the whole story came out. The only thing common between losing my Neptune and finding it again is my rig (wasn't wearing the same jumpsuit or helmet) so I can only assume that the Neptune must have dropped into my canopy or container at some point and I packed it in there. I didn't notice it come out on opening. I was very fortuitous that the 2-way freefly jump I was doing as well as the configuration of the rest of the load allowed me to be in the first group to exit. Also the weather conditions were very calm so the spot was right over the top. Plus we'd had a torrential downpour earlier in the day which must had softened the ground up, plus it landed on the grass and not the concrete ten feet away (or on someone's head or car!). There is not a scratch on my Neptune! Even the LCD screen (arguably to most fragile part of the unit) is completely intact! Just incredible.

There is only one small disappointment though. When I got home last night, I eagerly downloaded the unit to determine what the terminal velocity of a freefalling Neptune is, only to find out that the jump had no detailed profile. The logbook is switched on in the unit, it recorded the exit and deployment altitudes and freefall time correctly, and it has profiles for the next jumps, but the one in question is blank. Could the shock of "going in" have prevented it from logging it completely?!

Whatever, I'm very pleased to have my Neptune back! As well has having a lot of sentimental value to me, it really is a cool bit of kit, that I really like. I really don't deserve the nice things I have and I must look after them better!

So what other interesting things have been packed into canopies/container before and lost/found on opening?! Have heard stories of wallets before. And I have packed a jack knife (in a sheath) into my canopy many years ago but found it as I was squeezing the air out!

Skydiving Fatalities - Cease not to learn 'til thou cease to live

[Elisha 1]

http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=1760559;search_string=presents%20canopy;#1760559

[eUrNiCc 0]

I once did a 2 way with a friend, following a 6 way out of the otter. The jump went fine; I opened at 3000 and flew my normal pattern. During my downwind leg at about 900ft I saw a purple blur whiz past my left side and instantly identified it as the helmet belonging to a girl on the 6way that exited before me. I watched it all the way to the ground. I landed next to the helmetless girl who said that she had just bought a new helmet and pro-track and didn't have it adjusted very well yet. At 6000ft it came off and she figured that she'd never see it again. I walked her over to the other end of the landing area where I had seen it frap in. She picked it up and was amazed that it had sustained no damage whatsoever, not even a scratch. The protrack inside had recorded the jump, but not the opening altitude.

I've also heard of some camera helmets going in and sustaining little damage.

Egad, A BASE life defiles a bad age.

[Eule 0]

Quote

The logbook is switched on in the unit, it recorded the exit and deployment altitudes and freefall time correctly, and it has profiles for the next jumps, but the one in question is blank. Could the shock of "going in" have prevented it from logging it completely?!

My guess would be that its algorithm goes something like this, once it thinks it's in free fall...

highest_freefall_speed = 0;


while(speed > 20)  /* or some other "minimum" speed of free fall */

{

speed = measure_speed();

if(speed > highest_freefall_speed)

{

highest_freefall_speed = speed;

}

}


/* now we are under canopy */


store_to_nonvolatile_memory(max_freefall_speed);

The reason it waits until it thinks it's under canopy to record the max freefall speed is that often, writing to the non-voltatile memory (flash) is rather slower than writing to the volatile memory (RAM). In freefall, it doesn't want to spend a lot of time writing to non-volatile memory, as then it might miss a momentarily higher freefall speed. So it just keeps looping quickly and keeping the highest speed it saw in RAM.

If it fell out early enough in the deployment, it probably never slowed down enough to register "I'm under canopy now" and write the max freefall speed to non-volatile memory. It just kept looping and kept the max freefall speed in RAM. I would further guess that it might have suffered a momentary power loss at impact (was the battery still in it when the guy found it, or had it popped out?), OR it kept running, but a built-in time out caused it to "give up" on that jump after, say, 15 minutes or so. On the other hand, maybe it should have seen the zero speed after it landed and concluded that it was under canopy, and gone ahead and recorded the max speed.

A little rough estimating says that if it was falling with its smallest face down (least cross section into the relative wind), it might have hit 100 mph or so. There is probably at least +/- 30% tolerance on this estimate, though.

It might be interesting to ask Alti-2 about this. They probably already know what terminal velocity of a Neptune is, but they might be able to explain better why it didn't log the speed.

Eule

PLF does not stand for Please Land on Face.

[mdrejhon 8]

What does the opening altitude on Neptune say? 0 feet? You might be able to calculate the terminal velocity this way. If you leaped at 14000 feet and oened at 3000 feet, and you normally belly fly for 60 seconds during this time period. But if you lost your Neptune at 3000 feet as you were opening and Neptune recorded 1 minute and 30 seconds of free fall, the "opening altitude" would read 0 feet (the impact with the ground). That would mean it spent 30 seconds freefalling from 3000 feet, from whereupon you can calculate the speed would be approximately 80mph.

Most likely terminal velocity is probably more like 40mph or thereabouts for a falling neptune that's tumbling (it's not an aerodynamic shape). I'd wager to bet that a falling Neptune never reaches 100mph -- a Neptune is an awfully light piece of electronics since it comes in a plastic case.

Quote

Quote

The logbook is switched on in the unit, it recorded the exit and deployment altitudes and freefall time correctly, and it has profiles for the next jumps, but the one in question is blank. Could the shock of "going in" have prevented it from logging it completely?!

My guess would be that its algorithm goes something like this, once it thinks it's in free fall...

highest_freefall_speed = 0;


while(speed > 20)  /* or some other "minimum" speed of free fall */

{

speed = measure_speed();

if(speed > highest_freefall_speed)

{

highest_freefall_speed = speed;

}

}


/* now we are under canopy */


store_to_nonvolatile_memory(max_freefall_speed);

The reason it waits until it thinks it's under canopy to record the max freefall speed is that often, writing to the non-voltatile memory (flash) is rather slower than writing to the volatile memory (RAM). In freefall, it doesn't want to spend a lot of time writing to non-volatile memory, as then it might miss a momentarily higher freefall speed. So it just keeps looping quickly and keeping the highest speed it saw in RAM.

If it fell out early enough in the deployment, it probably never slowed down enough to register "I'm under canopy now" and write the max freefall speed to non-volatile memory. It just kept looping and kept the max freefall speed in RAM. I would further guess that it might have suffered a momentary power loss at impact (was the battery still in it when the guy found it, or had it popped out?), OR it kept running, but a built-in time out caused it to "give up" on that jump after, say, 15 minutes or so. On the other hand, maybe it should have seen the zero speed after it landed and concluded that it was under canopy, and gone ahead and recorded the max speed.

A little rough estimating says that if it was falling with its smallest face down (least cross section into the relative wind), it might have hit 100 mph or so. There is probably at least +/- 30% tolerance on this estimate, though.

It might be interesting to ask Alti-2 about this. They probably already know what terminal velocity of a Neptune is, but they might be able to explain better why it didn't log the speed.

Eule

[meatbomb 0]

Quote

So what other interesting things have been packed into canopies/container before and lost/found on opening?!

Well...two stories...one I know to be true, as it happened to me...the other...well you decide...

I usually attach my helmet to my chest strap buckle once I land, and put my gloves/alti in it, so as not to lose it...for some reason, in this case, I decided to use a packer...(this was the first and last time for this packer!)...I went to pick up my rig, and found that the hat and stuff was gone. I found the stuff on the floor, and figured that my frappe hat had gone walkabout...went up to jump, deployed, and low and behold, my frappe hat comes flying out of my canopy, and down below me. I immediately started chasing it down, and was surprised to note that I could keep level with it by spiralling around it (on my Sabre 190 - 1.4). Of course, due to my magnificent spot (ahem), the frappe hat landed in our gravel pit!
The Pro-Track contained was unharmed, and had registered the exit, and an opening height of 800ft.

The second story I didn't witness, but apparently happened at Strathallan in the early-mid 90s. I have been related it by several independent sources, but it still sounds amazing! Basically, someone managed to scoop up a baby rabbit into one of the cells of their 7-cell canopy, when picking it up after a jump. It wasn't noticed when packed, and when the rig was jumped, the jumper was shocked to look up and see this rabbit running up and down one of his cells! On landing, it popped out of the cell and hopped away, possibly the first (and only) skydiving rabbit!

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Swoopert, CS-Aiiiiiii!
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