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-   -   Parachute jump from hell (https://www.pprune.org/rotorheads/546742-parachute-jump-hell.html)

soloviev 1st Sep 2014 14:42

Parachute jump from hell
 
Hi. A friend of mine asked about the possibility to do vinculated parachute jumps from an hovering helicopter.
Well, to me it seems the limitation is about the length of the vinculating rope who can interfere with rotors. I did not see at the moment any other main issue.
Any suggestion about?

Vovick 1st Sep 2014 17:25

What is vinculated? Static line?

Gordy 1st Sep 2014 19:34

Do you mean "bungee" jump?

Straight parachute jumps are not a problem.

MightyGem 1st Sep 2014 19:44

Hmmm...vinculate: to tie or bind.
Vinculate - definition, etymology and usage, examples and related words

fijdor 1st Sep 2014 22:07

Yep, the definition you posted fit the tread title.:8

JD

Treg 1st Sep 2014 23:25

I and colleagues completed a number of static line jumps from B212 in the eighties. We did not hover, but maintained about 40kts. Static lines secured to floor rings resulting in bags not extending much past the skid.

I never questioned the safety of this at the time... just did as I was told...

Boudreaux Bob 1st Sep 2014 23:41

Lots of things to consider about Static Line Jumping from helicopters.

Biggest thing is making sure nothing can get into any of the Rotor Blades (Main and Tail Rotor) or any other moving parts.

Also, making sure nothing on the Jumper can get hung up on anything.

Guarding Reserve and Main Chute deployment mechanisms really take on a new meaning in Helicopters as compared to Airplanes.


Gomer Pylot 2nd Sep 2014 00:15

Jumping from a helicopter is much easier than from a fixed-wing. I've done many jumps back in my younger days, and have flown jumpers in helicopters. As long as the static lines are a reasonable length and properly secured, there should be no problems. You need someone in the back to get the static lines back inside, so they don't bang the fuselage too badly, but otherwise it's a piece of cake. Don't expect a hover, because out of ground effect hover takes lots of power, and it may not be possible. We normally flew at 60 knots or so, there is no need for a hover.

John Eacott 2nd Sep 2014 01:35

Since the OP specifically asked about from a hovering helicopter, I've done this on numerous occasions, but never with a static line.

The jumpers specifically wanted a hover (below 10kias would do, really) because that gives them no airflow and therefore no stability until they pick up at 32ft/sec. Apparently it gives a totally different aspect to the jump, I guess akin to a balloon departure? But with a static line this 'buzz' would be virtually non-existent since the line and rapid deployment of the chute would give a quick stabilisation to the event.

Usual stuff about ensuring they depart evenly from both sides, step off and don't push off the fuselage, etc. As with other comments the length of the static line must be short enough not to create a problem, and a jumpmaster becomes essential to retrieve the static lines thus dictating a helicopter cabin size dependent on the number leaving and the number remaining.

Boudreaux Bob 2nd Sep 2014 01:43


SuperF 2nd Sep 2014 05:07

i was about to say that there is a video somewhere showing exactly why a pilot wouldn't want to fly parachuters, looks like BB beat me to it.

not a dig at the guys, they did well to get the chute back in and not send it into the tail, but if they hadn't thought about that and just cut it free, then we could have been watching a very different video!

i for one won't be putting my hand up to carry parachuters any time soon.

soloviev 2nd Sep 2014 06:24

Thanks to those correcting my English, I think static line is what I meant.
Well, interesting answers, thanks a lot.
My friend is a jumper and he wants to try a static jump from an AS350. Static line is 7 mt long. I've not calculated but 7 mt seems very long for the size of the 350, even if somebody from the cabin is recovering the lines and the helicopter is virtually hovering (yes, a bit of fwd speed would be beneficial).
I'll take a moment to make some measurement on a real 350, please let me know if any of you have interesting suggestions.

Vovick 2nd Sep 2014 06:33

What rig is he going to jump with? D-1-5U? Send him to Antonov-2 instead.

OvertHawk 2nd Sep 2014 07:42

7 metres!!! :eek:

Get someone to video the crash :=

Treg 2nd Sep 2014 10:57

Quote: ...I guess akin to a balloon departure? But with a static line this 'buzz' would be virtually non-existent since the line and rapid deployment of the chute would give a quick stabilisation to the event...

John, I had a static line jump out of the Swan Airship that would challenge the 'virtually non-existant' suggestion.

Having the door opened in silence and then stepping down onto the airship entry step with nothing but the sound of voices from the cabin as PAX watched on was very new. Also the unexpected feeling of fear after 40 odd jumps from fixed wing with equipment was not what I had expected.

However, the real sting was the extended deployment of the canopy due to the low (zero) initial airspeed on exit. Normally deployed within three seconds, my count had reached the LOOK, LOCATE of the cutaway drill as the snivelling canopy finally got its act together... LOCATE was followed with thank f@$k for that!

Boudreaux Bob 2nd Sep 2014 11:56

Treg,

There is a huge difference in the sound the rubber bands make as the shroud lines are removed during the opening process isn't it?

From an Airplane even....compared to Free Fall where one is at Terminal Velocity (Terminal....now there is a concept to that takes on new meaning when it comes to parachutes).

At slow speed...you can hear each one of them....."Thrup........Thrup.......Thrup....." but in Free Fall it is a single "Brrrrrrp" kind of sound.

A near Hover drop of a Static line Jumpers from a Chinook made for great Chuckles from the Chinook Crew. The Down Wash and near zero forward speed made for some very interesting openings when the Troops had only done C-130 and C-141 Jumps.:)

A seven Meter long Static Line on a 350......NO....NO....Hell NO!

soloviev 2nd Sep 2014 12:26

I do agree with those of you who disapprove the 7 meters on the 350.
But I've no experience on parachutes, I have my opinion on the job but just wanted to see listen to those who are experienced. Finally I found myself not so far from your mostly agreed opinion.
I don't know neither the parachute model nor the reason for the 7 meters long line, I'll certainly ask the jumper.

Jet Ranger 2nd Sep 2014 12:41

Although we are throwing them almost every week from FL100 in our B212, we´ve never done that with the static line. A few years ago they asked, and we refused to do that. Big NO to that :=.

They can get min. airspeed of 50-60 kts, max. 10.000 ft and that´s it.

With the all safety briefings and measures, they succeeded to rip off our 212 left doors, once ...:ugh:

JR

Treg 2nd Sep 2014 12:43

BB

Although I chuckled at your story, for some strange reason my palms started sweating.

The airship was at our base as a trial for bushfire spotting/command evaluation (this failed due low forward speed and typically high winds). We, a PJ team of around eight, had been asking for a jump the moment it arrived but were told no, no, No! This is not a toy... or words to that effect.

On the last day of the evaluation I just happened to be in the right place at the right time and my boss said, "wanna go for a leap?" 20min later we were geared up walking past other team members who were reasonably pissed that they had missed out.

My gloating remark of "too bad boys" as we climbed aboard the airship would come back to bite me. As my canopy flapped in the breeze during deployment they pissed themselves laughing and were not shy in taking the piss afterwards.

Happy days...:ok:

Gomer Pylot 3rd Sep 2014 00:24

The static lines we used in the US Army for jumping from UH1s were on the order of 2-3 meters or so, IIRC, although it's been about almost 40 years since I last used one. 7 meters is out of the question even for a UH1, and certainly for an AS350.


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