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fcajump

Wrist vs Chest - Altitude shown

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"Wear two watches and you'll never know what time it is..." -unknown-

Anyone else out there still wear a chest AND a wrist Altimeter?

If you do, I'm curious as to any noted difference in reported alt between the two... (belly fly, stable)

JW
Always remember that some clouds are harder than others...

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I wear a wrist, chest, and audible. The wrist, I can see while on grips, the chest, others in the formation can see, and the audible tells me when my student should pull, I should pull for him, and when I should give up trying and save myself. They all usually read within 2-300 feet of each other.

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fcajump

Anyone else out there still wear a chest AND a wrist Altimeter? If you do, I'm curious as to any noted difference in reported alt between the two.



I often use both, but use only a chest mount when I'm doing a hop-n-pop. I still wear a chest mount even when I wear a wrist mount because that is what I "grew up" using, and because I have my hook knife pouch sewn to the cushion. I have never bothered to see if there was any difference between them.

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lyosha

Chest mount analog for the jump + wrist digital for under canopy + audible for, well, an audible.



Same. I started with an Altimaster Galaxy on my wrist during AFF, switched to AltiTrack at ~80 jumps, added a Quattro audible at ~180, and moved the Galaxy to my chest strap at 200 for wingsuiting. I tried comparing the AltiTrack and Galaxy in flight this past weekend, but couldn't see the former well enough. During climb, the Galaxy seems to indicate 2-300 ft lower than the AltiTrack and the audible.

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fcajump

"Wear two watches and you'll never know what time it is..." -unknown-

Anyone else out there still wear a chest AND a wrist Altimeter?

If you do, I'm curious as to any noted difference in reported alt between the two... (belly fly, stable)

JW




lol... I normally have 3 analog altimeters and some times 4 ! It really freaks people out sometimes. I tell them I'm afraid of heights lol...

Even you hand or wrist mounted altimeter will very up to around 200ft depending on your hand position. Additionally, depending on the design of the altimeter, exposing it directly to the relative wind (I am not talking about a chest mount location) can cause the altimeter to read low.

When I am tracking hard and flat, (grabbing air), my chest boundary layer pressure goes up, and the altimeter will read as much as 500Ft lower than I am.


In regards to;

"During climb, the Galaxy seems to indicate 2-300 ft lower than the AltiTrack and the audible."

Mechanical altimeters are calibrated for descent. On the way up they should be really close till around 6K, then you will start to notice them start to "lag" a bit. The issues that cause that "lag" are compensated for in the descent calibration.

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fcajump

"Wear two watches and you'll never know what time it is..." -unknown-

Anyone else out there still wear a chest AND a wrist Altimeter?

If you do, I'm curious as to any noted difference in reported alt between the two... (belly fly, stable)

JW

I don't need no stinkin altimeter.B|
I hold it true, whate'er befall;
I feel it, when I sorrow most;
'Tis better to have loved and lost
Than never to have loved at all.

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Having gotten some feedback, the reason I ask...

I usually wear a Altitrack (digital/recording) wrist and an old Altimaster III (analog) on my chest.

While I would not be surprised by some variation, I'm getting almost 1000'ft difference.

When flat/stable belly flying, the chest mount is ~1000' lower than the wrist. (Note, they read the same when on the ground, in the plane and under canopy.)

While I tend to trust the digital more (newer tech, newer device, less influenced by mount position), when you're down in the 3k' range, that 1k' difference can be unsettling.

My guess is that the chest mount is experiencing a higher pressure due to... as I tell my wife... bow-wave. I'm broad chested and tend to have a higher than average fall rate.

Will have to find my old wrist mount for the Altimaster for comparison in a identical location.

Thanks all,
JW
Always remember that some clouds are harder than others...

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FWIW -

Played around on a couple jumps this weekend -

Flat/Stable/Belly - wrist (extended) showed ~1000' higher than the chest mount.

Brought my wrist mount (Altitrack) into my chest and initially the difference was there, but then it 'caught up' to my analog chest mount. Extend the arm back into free air and it slowed way down until the difference resumed at ~1000'.

I figured there would be a difference... just surprised at how much.

JW
Always remember that some clouds are harder than others...

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