Questions from a writer

[EdBarron 0]

Hello there,

I am not a skydiver although I plan to make it part of my schooling for my private pilot’s licence. Therefore, today I am hoping for some info from the insiders for a book that I am writing.

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During freefall is it true that the noise of the air rushing past is considerable?

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On a skydiver website the answer to the question what one should wear for a jump was short trousers and t-shirt on a warm summer’s day. At 3500ft air temperature in most temperate places around the world should be about 0 deg C / 32 deg F. That would make the suggested clothing a rather frosty choice, especially when adding the chill factor of the wind. How cold is it really for a skydiver?

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This one might be a bit of a gruesome one for some people but I am trying to stay as close as possible to the physical reality. If a person fell out of a plane at about 3000ft without a parachute he or she should reach a hefty 125 mph. Does anyone know whether the body would leave an impact indentation in medium soft ground under those conditions (a paddock, for example)?

I am grateful for any information or pointers to other sources.

Many thanks

Ed

[gowlerk 1,901]

1) Yes 125 mph wind is quite noisy. After the parachute opens people find the difference startling.

2) Only in very warm places would people regularly jump in just shorts. That advice probably is given for a place that is selling tandem jumps, and is likely based on wearing a jumpsuit over top. Although it is generally warmer than that at 3500 ft, most jumps are from 11,000 to 14,000 ft. Conditions vary like the seasons, but can be very cold at times.

3) In soft ground a falling body is said to leave a "crater"

Always remember the brave children who died defending your right to bear arms. Freedom is not free.

[FlyingRhenquest 1]

1. Yeah, it's loud. see for yourself. With that wind going by I could be screaming and you'd never know it (I wasn't, but I could have been!)

2. The temperature goes down about 3 to 5 degrees (farenheit) per 1000 feet. In the summer we'll open the jump door at 2000 feet to cool the plane down, and leave it open potentially as high as 8 or 9 grand depending on who's sitting by the door. 12000 feet on a hot day is really pretty comfortable. I mostly wear a jumpsuit for the added wind resistance and because I have a tendency to get scraped up and an extra layer of cloth prevents the worst of that.

3. Don't really know honestly. I've heard on hard ground we tend to bounce surprisingly high. You'd be dead instantly, of course, from the G forces involved. Probably wouldn't even feel it.

Terminal velocity changes with the weight of the subject and his body position. I hit 170 mph a couple of times during my AFF training (Yes, with stable belly position!) I've lost about 30 pounds since then can vary my fall rate from mid 120s to mid 170s by changing my body position. I've crossed 170 in dives a couple of times - my altimeter logs my speed at various altitudes.

Sticky McFloatypants over there could easy fall in the mid 90's. He actually presents more of a problem to instructors than I did -- it's easy enough to add weight to fall faster. Not so easy to fall slower...

I'm trying to teach myself how to set things on fire with my mind. Hey... is it hot in here?

[GLIDEANGLE 1]

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During freefall is it true that the noise of the air rushing past is considerable?

Yes. With rare exceptions... it is impossible to hear speech in freefall.

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On a skydiver website the answer to the question what one should wear for a jump was short trousers and t-shirt on a warm summer’s day. At 3500ft air temperature in most temperate places around the world should be about 0 deg C / 32 deg F. That would make the suggested clothing a rather frosty choice, especially when adding the chill factor of the wind. How cold is it really for a skydiver?

Most jumps are made from much higher than that! Typical would be ~13,500ft. I live in Texas. In summer here, shorts are a perfectly reasonable, and fun, thing to wear. In winter, temps can be well below freezing at exit altitude... even in Texas.

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This one might be a bit of a gruesome one for some people but I am trying to stay as close as possible to the physical reality. If a person fell out of a plane at about 3000ft without a parachute he or she should reach a hefty 125 mph. Does anyone know whether the body would leave an impact indentation in medium soft ground under those conditions (a paddock, for example)?

I can't say..... thankfully.

The choices we make have consequences, for us & for others!

[decompresion 2]

Some Writer Dude

During freefall is it true that the noise of the air rushing past is considerable?

It is loud white noise that drowns out everything else. If you put your mouth directly on someone's ear at the right orientation, they can hear you surprisingly well.

Flying Popsicle

How cold is it really for a skydiver?

- You don't wear a jumpsuit just to protect you from the cold.
- You might like the protection from possible scrapes and nicks. The suit also serves as a source of drag. Want to go fast? wear slippery tight clothes (or wear weights). Want to go slow? wear baggy rough clothes.
- It can get nippy at higher altitudes

Wrong. Just wrong

Does anyone know whether the body would leave an impact indentation in medium soft ground under those conditions?

Yes

There are no dangerous dives
Only dangerous divers

[councilman24 36]

Your got 1.

In the upper midwest shorts and t-shirt are okay in summer. At 3500' during the summer it's much warmer than 32F. If 80 on the ground more like 60-70 in the air. 30-40F at 12000. Remember, even though you wouldn't want to stand around on the ground in 120mph wind at 30F in shorts for very long we are not in freefall very long. And most jumpers wear a jumpsuit of some kind. For added control, for added warmth, for added protection, to keep loose clothing from interfering with equipment, to look cool and match their rig, etc.

Yes, a body does leave a shallow crater in ground in damp woods near standing water. With some undergrowth it was only 3-4 inches deep. The body was about 6' from the crater, indicating that indeed it did bounce. You wanted to know.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[dthames 0]

Annoyingly loud to me. I wear earplugs.

Shorts and a T-shirt at 13,000 in the south US, in the summer is still plenty warm. I have jumped with a small wet towel around the back of my neck with the ends tucked into my suit because it was so hot on the ground. Jumping out with that wet towel and wingsuit flying, the towel does get cold enough that I notice the chill, but it feels great.

Instructor quote, “What's weird is that you're older than my dad!”

[Tink1717 2]

Why are you wanting to learn to jump as part of pilot training?

In answer to your questions:

1. The wind noise in Freefall is extremely loud. The only time you can hear anything but the wind, is under some exact conditions during a tandem jump.

2. Yeah, it can get frosty up there even ona hot day but you're not out in its long enough to do any real damage in summer time. Mostly it feels good.

3. Yes, it is possible for a jumper at terminal velocity to dent the planet. I've seen it.

Skydivers don't knock on Death's door. They ring the bell and runaway... It really pisses him off.
-The World Famous Tink. (I never heard of you either!!)
AA #2069 ASA#33 POPS#8808 Swooo 1717

[mjosparky 3]

On impact a body at terminal will leave a “crater” even in hard ground. I have seen them as deep as 6/7 inches. The body will usually bounce about 4 feet in the air and come to rest outside of the “crater”.

Sparky

My idea of a fair fight is clubbing baby seals

[oldwomanc6 38]

mjosparky

On impact a body at terminal will leave a “crater” even in hard ground. I have seen them as deep as 6/7 inches. The body will usually bounce about 4 feet in the air and come to rest outside of the “crater”.

Sparky

I think we've seen the same craters.

And yes they visibly bounce.

lisa
WSCR 594
FB 1023
CBDB 9

[skybum1 0]

I think the noise from freefall is awesome. And not as "extremely" loud as you might think. Didn't you hear them talking in Point Break. It mostly depends on exposure time. How many db/hr. Which is worse for your hearing, 45sec of freefall noise or 30min in the cockpit without earplugs?

[labrys 0]

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In the upper midwest shorts and t-shirt are okay in summer. At 3500' during the summer it's much warmer than 32F. If 80 on the ground more like 60-70 in the air. 30-40F at 12000

On the hottest days of summer in Ohio, one of my favorite things to do after a full day at the DZ, on the sunset load, is to doff the jumpsuit and do a high pull around 12000 in shorts and a t-shirt with a cold beverage in a side pocket and enjoy the 40ish degree weather for 5 or 10 minutes.

It's like standing in front of an air conditioner after you've been working on your lawn all day...

Wearing shorts and a t-shirt down to 3000-2500 feet for 60 seconds is nothing compared to a high hop-n-pop.

ETA: Yeah, you can yell loud enough to be heard in freefall, but only if you're yelling as loud as you can into the other person's ear from a few inches away.

That video posted early on seemed pretty accurate until the guy with the camera deployed and then it seemed pretty weird because the noise didn't decrease much after his canopy was open. But is there's a lot of wind after you open... I guess it's possible.

Owned by Remi #?

[DrDom 0]

When you do your PP, ask them to take you up in a piper cub, leave the door open (yes, its very nice to fly door open on them... its like a motorcycle) and remove your headset. Stick your head into the airstream. Its about 70MPH plus the prop stream. Its loud. Or head to the wind tunnel even WITH ear plugs in you'll know it is loud.

3.5deg/10,000ft is what I've heard. Youre only there for a second so its a lot like reaching into the freezer to grab a bottle of vodka and taking your hand out. You warm up about 3.5degF/10seconds on the way down. From experience, as a new jumper... you're not shaking because of the cold, and your toes arent numb because of the wind chill. Adrenaline has a numbing quality on temperature perception. You'll sweat anyway ;)

Crater? Depends on the ground but I have seen people fall off small buildings and leave a small "dent" in soft earth. In blacktop or concrete this may vary depending on the nature of the material. Hell.. I landed pretty hard after a high flare and there was a dent where I made my PLF (with no injuries by the way, other than my pride). It was fairly soft dirt the day after a rain with the exception of the big granite rock I rolled over (which, in fact, did not dent or even move at all)

You are not the contents of your wallet.

[billvon 2,379]

>During freefall is it true that the noise of the air rushing past is considerable?

Deafening. Painful without a helmet. With one it's tolerable but is still very loud.

>How cold is it really for a skydiver?

Pretty cold. Two extreme examples:

Jump during the 2002 300-ways. Exit temps at 24,000 feet was -34F. I exited (with three layers on) took one breath, was shocked by how cold it was, breathed out - and my faceplate froze. Couldn't see anything.

30,000 foot jump in Rantoul one year. I got up early but completely forgot how cold it was going to be; I had only shorts, a T-shirt, a thin jumpsuit and my (thin) leather gloves. It was actually OK, mainly because the airplane was warm (the Mullins King Air) and the short time you are above 10,000 feet (a little over a minute.)

In general the lapse rate makes it 30-50 degrees cooler at 12,500 than at ground level. Also in general since you are up there so short a time you can optimize for ground level rather than altitude. I generally dress for the plane ride, not the freefall. The only really dangerous part about cold temps are losing feeling in your hands. (And when it's really cold freezing faceplates, but that's rare.)

>Does anyone know whether the body would leave an impact indentation in medium soft
>ground under those conditions (a paddock, for example)?

In irrigated lawn they make an indentation a few inches deep.

[wolfriverjoe 1,339]

#1 - Yes. Very loud. The TV show Mythbusters on Discovery did this one.

#2 - It depends. Standard temp gradient is 3.5 degrees F per 1000 feet. It isn't always standard. It can be more than that, it can be less. I've jumped from 10k with an outside temp in the 50s F or 0F with temps on the ground in the upper 80s. I'll do low altitude exits 5000' or so without a jumpsuit, but not full altitude (more for control in the air than temp).

#3 - Yes. Depending on how hard the ground is, there can be a pretty significant divot.
I've seen the dent left by bad swoops, not terminal impact. One guy left 6" deep divot with his knees (both femurs were fractured).

"There are NO situations which do not call for a French Maid outfit." Lucky McSwervy

"~ya don't GET old by being weak & stupid!" - Airtwardo