Neptune freefall speed readings

[FireMedicJumper 0]

On a jump this past Saturday I generated some numbers on my neptune I don't quite believe.

The dive was a solo freefly which I took into a stand and held for the duration of the jump. According to my neptune, exit was from 13.4K and deployment at 3.6k. Freefall speeds were:

12K 123 mph
9K 192 mph
6k 255 mph
3k 24 mph

The neptune is mounted on the mudflap with a bonehead bracket.

Basically I'm wondering if being mounted in this configuration is causing it to read wrong or could the stand held for that long really have been that fast?

[everymansaved 0]

I don't know how much you weigh, etc... but I would say 225 in a stand from 13400 is more than possible. I got to a max of 184 on my back. If you were in a stand the entire dive, I'd believe it.

God made firefighters so paramedics would have heroes...and someone can put out the trailer fires.

[FireMedicJumper 0]

I weigh about 215-220 lbs exit weight. I'm inclined to believe the neptune since when I came out of the stand it was very rough. It almost felt like a freefall collision you might get on a funneled RW dive

[everymansaved 0]

Yea, slowing down after a ff dive can be quite noticeable, especially when you're doing a solo and don't have stuff like tracking, etc... on your mind.

God made firefighters so paramedics would have heroes...and someone can put out the trailer fires.

[breadhead 0]

While the Neptune is a great device (I own 2 of them myself), I have found the speed readings to be very unreliable.

[spoons 0]

Seems a little too fast to me.

I'm about 200lbs exit weight and in a stand with my arms above my head I can just get over 200mph (not saying you couldn't go faster
My Neptune quite often gives very odd readings on the altitude speeds...I tend to go off the average speed for the entire jump. What was the average speed?

[FFlyer 0]

I dont trust Neptune speed readings at all. Im happy with the altitude readings as I use it for my setup on landings but I dont even bother with what the speeds are because they always seem off.

Maybe it depends a lot on where the neptune is mounted but ive been on freefly jumps where the readings vary between 165mph - 300mph. And thats generally on team jumps where there are 3 of us doing a routine,....I really doubt those speeds are acurate.

[FireMedicJumper 0]

The average speed was 196. I think the speeds it gave me are possible, but not very likely. I'm not putting too much stock in the speed readings anyway. It's more of a novelty than anything else to me.

[tetra316 0]

I wouldn't rely on the readings. I once did 330, on a tandem according to my neptune!

[Remster 24]

Quote

While the Neptune is a great device (I own 2 of them myself), I have found the speed readings to be very unreliable.

What he said...

Remster

[brianfry713 0]

I get the occasional bad reading using the lastest sofware V2.6.0 and above. If you look at the version history http://www.alti-2.com/neptune%20owners/neptune_version_history.htm they changed: "Jump log speed calculations have been improved to prevent turbulent airflow result in wild velocity readings."

I actually think the old algorithm was better and gave me more accurate measurements of freefall speed. At least I didn't see occasional values like 350 mph. Note that if you use Paralog the graphs should be accurate, it just seems like the values displayed on the Neptune are sometime way off.

I've let Alti-2 know about this and hopefully they'll fix it in the next software release.