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54 votes
Accepted

Why don't militaries use ram-air parachutes?

You’ve made some faulty assumptions there as the military does use square chutes for specialist parachuting, but rounds are popular for several reason: Static-line round chutes are deployable en-...
Arkhem's user avatar
  • 1,122
34 votes
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What would have happened if the space balloonists had opened their parachute immediately when jumping off?

tl;dr Opening too high will kill you. As you note, the parachute would just hang next to them immediately after leaving the balloon -- there's too little air that high to even drag the shroud lines ...
Zeiss Ikon's user avatar
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31 votes
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What is the lift to drag ratio of a human being?

I'm an ex skydiver. It's a position known in skydiving as a "Flat Track", and is more or less the same configuration as a ski jumper takes. Legs together (ideally), bent forward at the hips ...
John K's user avatar
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29 votes
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How can skydivers start at 15,000 feet without the jumper suffering from hypoxia?

They don't. Hypoxia is an actual concern in medium and high altitude skydiving. It has been specifically researched as a possible safety risk. Skydivers jumping from over 10,000 ft do begin to exhibit ...
Therac's user avatar
  • 27.6k
28 votes

What is the risk of a single skydive?

Puzzled by this question I did my own research and found numbers that allows to get a good comparison for year 2016: According to the United States Parachute Association (USPA), there were 3.2 ...
Camilo Rada's user avatar
  • 1,251
25 votes
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D.B Cooper incident - What caused the tail to move after a jump?

The "sudden upward tail movement" requires nothing more than a sudden unloading of the tail by removing that 90+ kg of man, parachute, and money. Even with an aircraft as large as a 727, suddenly ...
Zeiss Ikon's user avatar
  • 17.1k
13 votes

How can skydivers start at 15,000 feet without the jumper suffering from hypoxia?

You're right that we're taught that hypoxia might become an issue above 10,000ft but there is no magic line. It's not like at 9,999ft you're fine then BAM 10,000ft you're in trouble. Hypoxia affects ...
Jamiec's user avatar
  • 33.5k
12 votes

What is the risk of a single skydive?

Here is another way to understand risk perception in skydiving vs driving. In skydiving, equipment malfunction is the cause of 50% of deaths. The highly regulated automobile industry would never ...
Pilothead's user avatar
  • 20.7k
11 votes
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Please identify this unusual jump plane

That is an Aero L-29 Delfin Source: onespotter, photographer/copyright: Evgeniy Lebedev
DeltaLima's user avatar
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11 votes

Landing Wingsuit on Solid Ground or Water

The forward speed of a wingsuit flyer in steady state descent ranges from 100 mph to as much as 130 mph, depending on the specifications of the suit (membrane area and flier weight are the most ...
Zeiss Ikon's user avatar
  • 17.1k
10 votes
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Landing Wingsuit on Solid Ground or Water

Surviving a landing on solid ground or water in a wingsuit is not very likely. The speed of a skydiver using a wingsuit will be in the vicinity on 100 kts. While it is possible to steer a wingsuit ...
Jpe61's user avatar
  • 29.1k
9 votes

How can skydivers start at 15,000 feet without the jumper suffering from hypoxia?

I think the danger here is being overblown quite a bit. About a million people a year visit the top of Pikes Peak, at 14,112 feet, so not quite 15,000, but well over 10,000. They do keep oxygen ...
Jerry Coffin's user avatar
  • 3,177
8 votes
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What are the wind speed limits for skydiving?

Skydivers should have personal limits, just like pilots do. Landing safely becomes more and more difficult with higher wind speeds and with higher gust factor. This refers mainly to the ground winds- ...
Chris's user avatar
  • 16k
8 votes
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What should I expect to happen when I get on a skydiving flight

is there anything I as a passenger can do to improve the safety of the flight You should do exactly what your told, when your told and make sure you keep well clear of spinning propellers. You will ...
Jamiec's user avatar
  • 33.5k
6 votes

Are there any safety data on the aircraft used for skydiving?

You didn't mention any particular country, but for the US I found an NTSB report called On the Safety of Parachute Jump Operations. It's from 2008 so some of it may be dated, but it says that no ...
Pondlife's user avatar
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5 votes
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Could a plane catch up with a skydiver with a failed parachute?

If the plane was highly modified, was in a dive when the jumpers exited, and everyone had a pretty good idea of what they were doing, maybe... Red Bull sort of attempted this with their plane swap ...
Dave's user avatar
  • 101k
5 votes

Will the steep beta descent mode become illegal for new aircraft?

I wouldn't call it a "descent mode from altitude". It's considered to be a dangerous and foolish practice to operate an engine in ground beta (generally coming back into DISCING - blades flat) while ...
John K's user avatar
  • 132k
5 votes
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Danger for hot air balloon if someone jumps out

The basket and people must weight a couple thousand pounds so I can't see how a person with a parachute could have the dramatic effect that is described in his explanation. I am in no way arguing that ...
quiet flyer's user avatar
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4 votes
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Are there any safety data on the aircraft used for skydiving?

I'm an ex jumper and I'd say the two major risks in a skydiving airplane ride are engine failure on take off or while too low to bail out, and a canopy deployment out an open door while in flight. ...
John K's user avatar
  • 132k
4 votes

Steepest climb a wingsuit pilot can achieve?

Wrong: A climb of 64 degrees was momentarily reached by Luke Rogers on Sept. 9, 2018 near Brisbane, Australia. This was 65 seconds into his flight track, where the climb rate was 153 km/h and the ...
Camille Goudeseune's user avatar
3 votes
Accepted

Why/how is a downplane parachute configuration aerodynamically stable?

The parachutes are both being pulled straight down from a single point. That means the relative airflow, or angle of attack, is straight up. Lift is perpendicular to the AOA. Even if the parachutes ...
John K's user avatar
  • 132k
3 votes

What should I expect to happen when I get on a skydiving flight

One thing to look (not just for this, but for with all aspects of aviation) is evidence of a Safety Culture. A skydiving operation is no different. Skybrary defines Safety Culture as follows: ...
Canuk's user avatar
  • 8,482
3 votes

Could a plane catch up with a skydiver with a failed parachute?

As a choreographed stunt, it would be very difficult and dangerous, but might be possible. The drop plane would need to be in a nearly-vertical dive, since a skydiver in free fall is falling nearly ...
Chris's user avatar
  • 16k
3 votes

Why don't militaries use ram-air parachutes?

There are serious military advantages to using a round "non steerable" parachute for mass tactical assaults. (And there are sometimes military reasons to use ram air or steerable rounds, ...
Geodkyt's user avatar
  • 31
3 votes

Why don't militaries use ram-air parachutes?

As Arkem stated, they use both, but the primary reason for the use of a simplified parachute is just that it's simplified. In general Airborne troopers are supposed to fall where they are told to, as ...
Mikeologist's user avatar
3 votes
Accepted

Do aircraft have to be certified specifically for skydiving?

Not really. You use whatever old beater airplane you can get your hands on with a suitable configuration. And you may not really need to do a mod like a jump door STC if you're willing to fly with ...
John K's user avatar
  • 132k
3 votes

Landing Wingsuit on Solid Ground or Water

I realize that there is an answer that has been accepted, but I'm going to offer a competing answer that differs - Yes, it would be possible to survive a landing on water. And it would be at least as ...
Michael Hall's user avatar
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3 votes
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Has a wingsuit pilot ever flown inverted for an extended period of time (say more than 5 seconds)?

Red Bull (who else?) did it: Umgedrehter Wingsuit-Flug über die Dolomiten (inverted wingsuit flight over the dolomites). It looks to be around 10 seconds. Parts of the video are in slow-motion, but ...
Jörg W Mittag's user avatar
3 votes

Who determines the minimum area needed for a sky diving dropzone?

Depends on the dropzone. If the dropzone is a member of the United States Parachute Association, it must meet the following Basic Safety Requirements (2024 SIM page 7) for the landing area: Areas ...
Oleg Pryadko's user avatar

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