Higher tech grav chutes

Discuss the Traveller RPG and its many settings
heron61
Mongoose
Posts: 185
Joined: Thu Oct 16, 2014 9:43 pm

Higher tech grav chutes

Postby heron61 » Sat Apr 18, 2020 6:45 am

Since grav belts are quite expensive, I was thinking about grav chutes and what they might be like a TLs higher than 10. Here's what I came up with - comments welcome:

Advanced Grav Chute
This device functions like a lower TL grav chute, except that the improved batteries are both rechargeable and can be used up to five times, with a maximum distance of 15 km per fall before they must be recharged. In addition, it permits limited lateral movement, with a speed of Very Slow. Like lower tech grav chutes, it cannot move the wearer upwards. This device is often built into armor and vac suits, which adds no mass and 5,000 Cr to the suit’s cost.

A thruster grav chute functions identically to an advanced grav chute, except that it also provides all the capabilities of TL 14 thruster pack (CSC, p. 28), and is also frequently built into armor and vac suits, which adds no mass and 22,000 Cr to the suit’s cost.

Image
steelbrok
Banded Mongoose
Posts: 297
Joined: Mon Aug 20, 2007 7:13 pm

Re: Higher tech grav chutes

Postby steelbrok » Sat Apr 18, 2020 1:36 pm

I can see them being useful for Jump Troops
phavoc
Cosmic Mongoose
Posts: 4910
Joined: Tue Nov 04, 2008 6:13 pm

Re: Higher tech grav chutes

Postby phavoc » Sat Apr 18, 2020 6:46 pm

If you are jumping in an atmosphere (and just falling) you'll reach terminal velocity quickly, and you won't continue to accelerate during your drop. Your velocity will be different, depending on your position (less air resistance = higher speed), but it's still terminal no matter which position you are in. On Earth it's 120mph.

I could see the cheaper grav chute being essentially a one-time use device. It only needs to activate right before you touch down, so it's duration would only need to be a few seconds for a combat drop (maybe up to 10, if you wanted to drop into urban environments and needed the extra time). That should help cut the costs down because the components only need to work once.
Condottiere
Warlord Mongoose
Posts: 8135
Joined: Mon Sep 23, 2013 8:23 pm

Re: Higher tech grav chutes

Postby Condottiere » Sat Apr 18, 2020 9:14 pm

Image

Primary and backup.

According to the United States Parachute Association (USPA) the recommended minimum deployment altitude varies depending upon which license is held by the person deploying the parachute. There are four licenses, plus student status. Students will typically deploy at 4000-4500ft AGL (Above Ground Level). Those holding a beginners license which is an "A" must deploy at 3500ft AGL, "B" is 3000ft AGL, "C' and "D" must deploy by 2500ft AGL. The S&TA (Safety/Training Advisor) may waive the minimum deployment altitude for C and D license holders from 2,500 feet down to 2,000 feet for a jump or a series of jumps if necessary. The absolute minimum consider safe to bail out of an aircraft using your reserve parachute on a sport parachute system is 1000ft., this would only be done during an aircraft emergency such as loss of power.

In theory and sometimes in practice these altitude advisories aren't followed for various reason, this places greater risk on the person choosing to do so. A sport parachute takes time to open, 400-800ft, that is called snivel and makes the sport more enjoyable because you not being jolted every time you deploy. The lower you deploy, the less time you have to deal with unexpected issues such as line twist. This narrows the window of opportunity to either fix the problem or cut-away and deploy the reserve parachute, which takes about 400ft to deploy and inflate.

Other parachutes, such as BASE rigs, are designed differently along with using different packing techniques to open very quickly during sub-terminal falling speeds. I know BASE jumpers who are comfortable jumping off objects 200ft in height. Some people have even jumped using BASE rigs at or around 80-90ft.

Military personnel can typically deploy at or around 400ft using a large-round parachute. I was told by a US Army soldier that they practice jumping from helicopters at or around 800ft.
heron61
Mongoose
Posts: 185
Joined: Thu Oct 16, 2014 9:43 pm

Re: Higher tech grav chutes

Postby heron61 » Sat Apr 18, 2020 10:06 pm

phavoc wrote:
Sat Apr 18, 2020 6:46 pm
I could see the cheaper grav chute being essentially a one-time use device. It only needs to activate right before you touch down, so it's duration would only need to be a few seconds for a combat drop (maybe up to 10, if you wanted to drop into urban environments and needed the extra time). That should help cut the costs down because the components only need to work once.
That's pretty much how the TL 10 version in the CSC is written. My version is for a reusable device that would be a handy addition to a vac suit (especially the version that's also a thruster).
phavoc
Cosmic Mongoose
Posts: 4910
Joined: Tue Nov 04, 2008 6:13 pm

Re: Higher tech grav chutes

Postby phavoc » Sun Apr 19, 2020 4:42 pm

heron61 wrote:
Sat Apr 18, 2020 10:06 pm
phavoc wrote:
Sat Apr 18, 2020 6:46 pm
I could see the cheaper grav chute being essentially a one-time use device. It only needs to activate right before you touch down, so it's duration would only need to be a few seconds for a combat drop (maybe up to 10, if you wanted to drop into urban environments and needed the extra time). That should help cut the costs down because the components only need to work once.
That's pretty much how the TL 10 version in the CSC is written. My version is for a reusable device that would be a handy addition to a vac suit (especially the version that's also a thruster).
Since you are proposing no vertical upward movement, perhaps then your device simply has longer-life batteries, but still one-shot electronics? Like once it's engaged you can use it to slow down, even hover, for say no more than five minutes, before the battery/circuits go out, and once activated it does the same when shut off?
heron61
Mongoose
Posts: 185
Joined: Thu Oct 16, 2014 9:43 pm

Re: Higher tech grav chutes

Postby heron61 » Sun Apr 19, 2020 10:58 pm

phavoc wrote:
Sun Apr 19, 2020 4:42 pm
Since you are proposing no vertical upward movement, perhaps then your device simply has longer-life batteries, but still one-shot electronics? Like once it's engaged you can use it to slow down, even hover, for say no more than five minutes, before the battery/circuits go out, and once activated it does the same when shut off?
I'd say that such a one-shot grave chute would be maybe 3,000-4,000 Cr, while a reusable and rechargable one (which seems like the only sort you'd want to build into a vacc suit or suit of armor) would cost more - maybe 6,000-7,000 Cr, rather than the 5,000 Cr I suggested. Thoughts?
Condottiere
Warlord Mongoose
Posts: 8135
Joined: Mon Sep 23, 2013 8:23 pm

Re: Higher tech grav chutes

Postby Condottiere » Mon Apr 20, 2020 10:42 am

Since inertial compensation isn't included, the minimum is the optimum deceleration rate without injuring the user, before hitting the ground, which would indicate energy usage.
phavoc
Cosmic Mongoose
Posts: 4910
Joined: Tue Nov 04, 2008 6:13 pm

Re: Higher tech grav chutes

Postby phavoc » Mon Apr 20, 2020 8:44 pm

heron61 wrote:
Sun Apr 19, 2020 10:58 pm
phavoc wrote:
Sun Apr 19, 2020 4:42 pm
Since you are proposing no vertical upward movement, perhaps then your device simply has longer-life batteries, but still one-shot electronics? Like once it's engaged you can use it to slow down, even hover, for say no more than five minutes, before the battery/circuits go out, and once activated it does the same when shut off?
I'd say that such a one-shot grave chute would be maybe 3,000-4,000 Cr, while a reusable and rechargable one (which seems like the only sort you'd want to build into a vacc suit or suit of armor) would cost more - maybe 6,000-7,000 Cr, rather than the 5,000 Cr I suggested. Thoughts?
Wouldn't the reusable/rechargeable one essentially be an equivalent to a grav belt already?
heron61
Mongoose
Posts: 185
Joined: Thu Oct 16, 2014 9:43 pm

Re: Higher tech grav chutes

Postby heron61 » Tue Apr 21, 2020 12:04 am

phavoc wrote:
Mon Apr 20, 2020 8:44 pm
heron61 wrote:
Sun Apr 19, 2020 10:58 pm
phavoc wrote:
Sun Apr 19, 2020 4:42 pm
Since you are proposing no vertical upward movement, perhaps then your device simply has longer-life batteries, but still one-shot electronics? Like once it's engaged you can use it to slow down, even hover, for say no more than five minutes, before the battery/circuits go out, and once activated it does the same when shut off?
I'd say that such a one-shot grave chute would be maybe 3,000-4,000 Cr, while a reusable and rechargable one (which seems like the only sort you'd want to build into a vacc suit or suit of armor) would cost more - maybe 6,000-7,000 Cr, rather than the 5,000 Cr I suggested. Thoughts?
Wouldn't the reusable/rechargeable one essentially be an equivalent to a grav belt already?
No, it's notably lower power - it can't actually lift the wearer and only functions for a short time - it just lets you fall any distance safely (and provides very limited horizontal movement when doing so).

Who is online

Users browsing this forum: heron61 and 40 guests