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A couple hours ago I was watching a youtube video where skydivers jump using the skydive parachute, and after that, a military training where the soldiers jump using "old" type parachute, the dome shaped one.

Why is the military using the dome shaped one?

The skydive parachute is smaller, and more compact, and has manoeuvrability (as I can see, I'm not an parachute expert).

Is it because of protection against enemy fire? Since it's larger it can take more damage of enemy firepower, or what?

DeltaLima
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sharp
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1 Answers1

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From what I learned, different types of parachutes don't make them 'old' or 'new'. They are used for different purposes.

For example the dome shape parachute is usually used for static line jump where no maneuverability is really required. They drop vertically relatively to the plane path when air friction is negligible.

The other kinds are usually used for special forces because they always do jumps like HAHO (High Altitude [Jump] High [Altitude] Open) when the location they jump is outside their country's territory, and infiltrate by air so the plane is out of the radar/SA missile range. They have to have the ability to glide on a long distance.

Another case is they have to have the ability to change the trajectory or precisely land in the drop zone. So maneuverability is a must.

Size differs for different manufacturer and different specs. Even though the dome type parachute is relatively larger, the chance of getting hit is similar with other types as you don't have much speed and you can't do crazy high G turns. You really can't avoid any attack towards you unless you have superhuman reactions and the sixth sense.

To conclude, different types of parachutes are used for different purposes in different scenarios.

T.J.L.
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Hezzte
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    Welcome! Very interesting answer. – mins Jun 13 '16 at 10:47
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    Ok, that's mostly advantages of the paraglide (rectangular, controllable) type. Yes, it is not always used. So what about the advantages of the round type? (AFAICT, the main advantage is that for the round one all you need is a bit of training on the landing and you are good to go while the controllable requires extensive training in controlling it). – Jan Hudec Jun 13 '16 at 11:35
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    They are cheaper because of the simpler control and as I mentioned they can go straight down relatively to the plane speed. The advantage of this is to control the drop zone of a lot of soldiers for the commander. As you mentioned round one requires less training and the fact that they are simpler, they have less chance to mess up with the controls and land on their dedicated drop zone. You don't want a bunch of soldiers to land with miles of separation and spend a few hours gathering them. In case of a quick response mission, the outcome will be disastouros. – Hezzte Jun 13 '16 at 11:48
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    I think the simplicity is key. All you need to know for a static line jump is how to fall out of the plane (trivial), bend your knees and roll when landing (everybody who has ever jumped off something higher than a chair knows that), and separate yourself from the parachute (the only bit that really requires training, and it's not that complicated – when in doubt, use your knife). For a steerable parachute, you need to learn, well, to steer it, and you need to learn to navigate (so you know where to steer to). More complex to learn plus more complex equipment == more to go wrong. – Jörg W Mittag Jun 13 '16 at 12:20
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    Dom-shaped parachutes are steerable, just not as much as high-performance chutes. You need to be able to steer to avoid obstacles on the ground. – Pete Becker Jun 13 '16 at 12:45
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    A couple hundred paratroopers steering their glide chutes around, flying into each other, getting their chutes tangled and plummeting to the ground. Now that sounds like fun. – DevSolar Jun 13 '16 at 12:54
  • Would there be a difference between a HAHO chute and a HALO chute? – Wayne Werner Jun 13 '16 at 13:24
  • I would guess that the larger area of the "traditional" round parachute is also able to support/slow a greater amount of weight than a performance chute would. This is a huge advantage when you have 175lb+ troops laden with an additional 50-100 lbs of gear falling out of the sky and wanting to land uninjured. – FreeMan Jun 13 '16 at 20:27
  • The impact force is actually higher when landing using a round parachute according to newton's third law – Hezzte Jun 14 '16 at 07:24
  • @Hezzte eh, I'll need some math to be convinced of what you say in your last comment – Federico Sep 07 '16 at 07:46
  • Total downward force = ( Massxg(9.81) - upward force(air resistance by the chute) – Hezzte Sep 07 '16 at 09:19
  • To make a "traditional" round parachute practical, it's air resistance should not be excess. But a glide chute can produce lift while gliding making it possible to control the downward force up creating an opposing upward force. That's why you can minimize the impact force by creating an upward force while using a glide chute. So the impact force will be relatively higher while using a round chute. @Federico – Hezzte Sep 07 '16 at 09:32
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    @FreeMan, no, the larger size of round chute is because it generates less upward force (it is considered drag, not lift) per unit area. You can design either for whatever weight you need by scaling it appropriately. – Jan Hudec Aug 06 '17 at 17:59