Vertical Descent Rate

[Hooknswoop 19]

Does anyone know how fast they are descending vertically (vertical airspeed) during their swoops? If yes, how are you measuring it?

Derek

[marks 0]

turn on your cypres, make a couple jumps and then send it to airtek for them to get the readings out of it.

[ianmdrennan 2]

Quote

Does anyone know how fast they are descending vertically (vertical airspeed) during their swoops? If yes, how are you measuring it?

Using Paralog and my neptune mounted in my helmet. I get vertical descent readings anywhere from 50-63 mph at my home dz on a velo 90 loaded from 2.2 to 2.4. The highest it has ever shown was 73 mph (with no plateau so there was still acceleration) loaded @ 2.2 on a velo 90 while at the CPC finals in CO. The turns are 270's.

Blues,
Ian

Performance Designs Factory Team

[SkymonkeyONE 4]

I am not sure, Derek, but I think you can get that reading on a Neptune in "swoop" mode. If not, I am pretty sure you can set it up if you have the admin software (like I do). I will have to call Alti-2 and ask Roger if that's possible.

[CanuckInUSA 0]

I've got a way to give us a rough idea as to how fast we're going, but I don't know how to get more precise at the moment you recover and pedulium (sp?) out of the turn. Anyway I was taught to combine time and altitude last year when I went out to CA for my first round of high performance canopy control coaching. I was taught that from the time I start my turn until the time I plane out should be 6-8 seconds. So if I start my turn at 800 feet and take the entire 8 second window to plane out, I am losing 100 feet per second. Now most of my turns are more in the 700 foot/6 second turn rate range so that give me 116.67 feet/second. How many feet are in a mile? 5280? (the metric system is so much easier to remember).

Let's do the math ...

((116.67 * 60) * 60) / 5280 = 79.54 mph

My God while my equation isn't 100% precise, I'm already over that mythical 78 mph mark. Now my descent rate has got to be less than the quoted 116.67 feet/second as I accelerate while I'm losing altitude in my turn, but it makes me think that we're a lot close to the firing speeds than we think we are. All the more reason not to go big on a regular load where the AAD is most beneficial and leave the AAD behind (or turned off) when we do plan on going big.

Try not to worry about the things you have no control over

[mattjw916 2]

Someone with a Vigil should be able to (relatively) easily provide this information if they had access to the IR download box and software.

NSCR-2376, SCR-15080

[Remster 30]

Thanks Ian. Its great to have some actual data to work from.

Some will probably say that the helmet isntthe bast place to measuring it, but its a start.

73 is damm close to 78 when it comes to critical measurements.

Remster

[Hooknswoop 19]

Cool Ian. Do you have a Cypres?

Derek

[ianmdrennan 2]

Quote

Cool Ian. Do you have a Cypres?

Yes. Until Colorado I had never considered turning off my cypres doing my regular turn with regular (2.2) loading. When I saw the chart I was quite shocked at how much faster it was. My thought is now, that in ultra high elevations at least, I'll be keeping my cypres off when loading up and doing 270's or more.

I then decided to load up at my home dz (with my cypres off) to just under 2.5 and do 450 degree turns to see what my descent rate would be. It never went above 64mph according to my neptune and even then was a short spike. I will be testing 270's this weekend but I expect the speed to be a good 5-10 mph slower.. I'll also throw out a couple of 630's for shits and giggles to see what they return loaded @ 2.4+

My expectation is that I will be below cypress firing speeds (according to how the neptune reads them as John Kallend has a valid point) at my home dz for all but the most extreme cases (2.5+ with more than 630 degree turns). At higher elevations though, where the air is thinner and the pilot is capable of generating greater descent rates I'd exercise a lot more caution.

Of course this is hardly a scientific approach but it's the best I've got given my tools and access to data.

Blues,
Ian

Performance Designs Factory Team

[YISkyDive 0]

I know this probably doesn’t mean much to the actual 78mph mark..

But on my Neptune on a Diablo 170 loaded at 1.3: 1 I hit 30s to 40mph on aggressive canopy direction transfers [toggles/ harness].. And in 270s up high. I know that on a Front riser 90 (carving) I do about 25mph vertical component.

More interestingly though- My father flies a crossfire2 139 loaded at about 1.9: 1 and he has found his max to be 67mph with harness 360. He does not swoop, but he commonly flies with a GPS logger unit and a wrist mount Neptune- The GPS profile of the jump indicates that the 67mph mark was from 1 360 harness turn alone, and he is sure that the second on is still notably faster. I'm at college right now, So i don’t have either the GPS profile or the Neptune profile, but that shows that even a fairly large wing at a decent loading has the ability to get up into redzone territory.

When he tests this kind of stuff- He uses the Neptune for a pure vertical component, and a GPS to associate the Neptune’s vertical component with maneuvers- ultimately he has programmed a 3d graph of his freefall / canopy flight in which you can actually run the cursor over his track and see his downward and horizontal speeds. Pretty neat stuff. None of us even thought of the idea of a cypress firing. Until recent event.

Oh yeah- The logger unit is Garmain Foretrex GPS logger - placed inside the back of a sidewinder helmet. He and I use diffrent Neptunes with the same update.


dave.



EDIT to ADD: The harness 360 was prety high as well, I'm not sure but i belive that it was 2000ft AGL and that would mean 2600MSL.

[superstu 0]

i've done a lot of experienting with all different kinds of turns and body positions and what ever. i don't know what i'm doing in MPH when i come in on a swoop, but up high i have hit 150+ m/s on my neptune which equates out to about 102mph. not really sure if that means anything to anybody but there's my info.

Slip Stream Air Sports
Do not go softly, do not go quietly, never back down

[cobaltdan 0]

using an atair datalogger 16bit resolution, 1000 samples per second (much more accurate than audiables):

i weigh 176+ gear and was jumping an onyx 75 . not pushing the canopy too hard i recorded a max of 87mph vertical.

Daniel Preston <><>
atairaerodynamics.com (sport)
atairaerospace.com (military)

[Hooknswoop 19]

Do you jump w/ an AAD?

Derek

[bob.dino 1]

Quote

i recorded a max of 87mph vertical.

How long was your vertical decent speed above 78mph?

[cobaltdan 0]

yes on the first jump i was jumping a cypress. i became extremely concerned by the high speed flight and recent death of adrian. i remained in brakes from 1500-750' before making my landing approach.

next jump i switched rigs.

with this canopy i can continuously sustain a speed in a spiral above 78 mph.

Daniel Preston <><>
atairaerodynamics.com (sport)
atairaerospace.com (military)

[Miami 0]

I have not measured my vertical decent rate but I would imagine it's pretty quick at a 3:1 w/l. I jump a cypres1 and in optimal conditions (no traffic/spot/weather issues) I start my hook at 1200' (usually 450-540 degrees total)...have been jumping like that for about 4 years now.

Miami

[Chilly_Dk 0]

At this moment I'm jumping an AltiTrack, a new altimeter being released by Larsen & Brusgaard in a very short time.
Basically, it is an digital/electronic altimeter with an analog display. On the inside (under the altimeter) it has a logging function known from the ProTrack.

One of the major advantages is that you are able to look at the data from your dive, as a timeframe from start to beginning. This means you are able to see your vertical speed at a certain time and altitude.

It is able to log your data while descending in canopy, and you are able to see it straight after the jump. Nice thing, not having to hook up a computer in between jumps


The first time I used it, I had some jumps on my Katana 120, and I was able to log vertical speeds on landing of around 65 mph.
I just got the one I have now, and I haven't had any decent landings on my Velocity since (Big ways with lots of traffic ), but I have a couple of registrations around 67-68 mph from 180s.
This is one of the things I'll be looking into for sure though while doing hop'n pops just for landings.

Read about the AltiTrack here

It's all right to have butterflies in your stomach. Just get them to fly in formation.