Personnel parachutes too fast

[Rafael acevedo]

I had Jeb, parachute out from an airplane, and deploy his parachute. His glide speed was 25m/sec which is way too fast. Terminal velocity for a human is  53 m/sec. a round parachute will land you at no higher than 19 m/s optimal  at 5 m/s. A square parachute as an airfoil will allow will allow you to land at between 1 and 3 m/s.  The best I could manage was 19 m/s. Currently the parachute is unusable. ( ksp 1.4 stock install). ( I am both a military and civilian parachutist and jumpmaster an useful book about this is the “Parachute Manual a technical treatise in aerodynamic decelerators”

Edited March 18, 2018 by Rafael acevedo

[MR L A]

Do you mean an actual landing speed rather than glide speed? Because ram air parachutes (the kind ksp uses) will have you gliding at around 11 to 13 m/s (25-30mph). 

Also, this is a game. Not real life. We have Kerbals surviving freefall from space occasionally, so lets be honest 9m/s might be too fast for a Human, but it is nothing like too fast for a Kerbal  But I guess being able to land without rolling across the floor would be nice... though having said that, it would be far too graceful for a Kerbal to be able to do that.

 

[Zeiss Ikon]

Don't forget that your velocity display is the scalar part of your vector velocity -- if you're gliding at (indicated) 25 m/s, you might only be sinking at 4 m/s (which would assume a 6:1 glide ratio -- I'm not sure what a modern airfoil parachute actually gives), so a little flare at the right time (just like when landing a jet or spaceplane) will cut your sink to near zero while your forward speed bleeds off.

It's hard to read accurately, but there's a vertical speed gauge just next to the altimeter (top of the screen, with default GUI locations).  It has a logarithmic scale, so there's as much needle movement between 10 m/s and 100 m/s as there is between 0 and 10, but in the ~10 to 0 range, you can tell pretty closely how fast you're falling.  Most of us use it as a Q&D indicator of Ap and Pe if we're doing seat-of-pants maneuvers in orbit, but it's also useful during aerodynamic flight, and the log scale makes it readable even at parachute velocity.

Edited March 18, 2018 by Zeiss Ikon

[Rafael acevedo]

7 hours ago, MR L A said:

Do you mean an actual landing speed rather than glide speed? Because ram air parachutes (the kind ksp uses) will have you gliding at around 11 to 13 m/s (25-30mph). 

Also, this is a game. Not real life. We have Kerbals surviving freefall from space occasionally, so lets be honest 9m/s might be too fast for a Human, but it is nothing like too fast for a Kerbal  But I guess being able to land without rolling across the floor would be nice... though having said that, it would be far too graceful for a Kerbal to be able to do that.

 

You are corrrect, modern ram air parachutes do have a forward speed of about 34 mph, which is why you turn against the wind on final and then flare your parachute. The idea is that if you do this correctly, you would land at 0 vertical, and 0 forward. Most skydiver average about 0 forward, 2 vertical.  Since you cannot turn against the wind in ksp this become imposible to do. Obtw I didn’t mean 9 m/s, it was 19 m/s

3 hours ago, Zeiss Ikon said:

Don't forget that your velocity display is the scalar part of your vector velocity -- if you're gliding at (indicated) 25 m/s, you might only be sinking at 4 m/s (which would assume a 6:1 glide ratio -- I'm not sure what a modern airfoil parachute actually gives), so a little flare at the right time (just like when landing a jet or spaceplane) will cut your sink to near zero while your forward speed bleeds off.

It's hard to read accurately, but there's a vertical speed gauge just next to the altimeter (top of the screen, with default GUI locations).  It has a logarithmic scale, so there's as much needle movement between 10 m/s and 100 m/s as there is between 0 and 10, but in the ~10 to 0 range, you can tell pretty closely how fast you're falling.  Most of us use it as a Q&D indicator of Ap and Pe if we're doing seat-of-pants maneuvers in orbit, but it's also useful during aerodynamic flight, and the log scale makes it readable even at parachute velocity.

A little flare at the right time lovely person my speed to 19 m/s and stalled killing Jeb 

[Zeiss Ikon]

I haven't tried it yet, but several others have reported landing Kerbals successfully on personnel parachutes.  Let me go see if I can reproduce that, and get back to you.

Edit: Okay, just tried it, bailed Jeb out of one of the stock jets around 400 m over the level ground near the Space Center (damaged the jet on takeoff, because I'm a sucky pilot with pushbutton controls), deployed his parachute as quickly as possible -- had a canopy at around 350 m.  Figured out how the parachute flight works on the way down, steered toward KSC and played with speed.  With view directly behind Jeb and level to the horizon, I was able (on my first try flying a parachute in game) to land Jeb at about 7 m/s, unsure what the vertical was (but not much).  Jeb tumbled, because Kerbals can't run that fast, but he lived.

This was my first time.  I have to presume you can do better.

What you probably need to do is look up how trims work and use elevator trim to slow down -- that' s what works well for flying airplanes in game.

Edited March 18, 2018 by Zeiss Ikon
add results of my own attempt

[Rafael acevedo]

33 minutes ago, Zeiss Ikon said:

I haven't tried it yet, but several others have reported landing Kerbals successfully on personnel parachutes.  Let me go see if I can reproduce that, and get back to you.

Edit: Okay, just tried it, bailed Jeb out of one of the stock jets around 400 m over the level ground near the Space Center (damaged the jet on takeoff, because I'm a sucky pilot with pushbutton controls), deployed his parachute as quickly as possible -- had a canopy at around 350 m.  Figured out how the parachute flight works on the way down, steered toward KSC and played with speed.  With view directly behind Jeb and level to the horizon, I was able (on my first try flying a parachute in game) to land Jeb at about 7 m/s, unsure what the vertical was (but not much).  Jeb tumbled, because Kerbals can't run that fast, but he lived.

This was my first time.  I have to presume you can do better.

What you probably need to do is look up how trims work and use elevator trim to slow down -- that' s what works well for flying airplanes in game.

Thank you will look at trim, managed a 6 m/ s Landing, but had to constantly fly the chute, don’t know how it would work for multiple crew

[Gargamel]

The people that do something very well in real life, find that game approximations of that activity are horrible.   I hated wii bowling, it just didn't feel right.  A lot of musicians hate Guitar Hero.  You are a jumpmaster.  So what is instinct to you, just doesn't fly in KSP (pun intended).  

[SpacedCowboy]

Not Human,,,I am KERBAL!

Really, they are a little "slick"

[MR L A]

1 hour ago, Gargamel said:

The people that do something very well in real life, find that game approximations of that activity are horrible.   I hated wii bowling, it just didn't feel right.  A lot of musicians hate Guitar Hero.  You are a jumpmaster.  So what is instinct to you, just doesn't fly in KSP (pun intended).  

I feel like the musicians hating guitar hero one is a little more than just because of it being a "game approximation" - it was just a funny shaped controller lol, nothing even vaguely like an instrument... at least wii bowling was a sort of simulation (just a bad one) and ksp parachutes are just iffy simulations of real ones. Guitar hero, whilst admittedly fun, could hardly be called an instrument simulator... even a REALLY bad one. It was just a quick time event sequence with 3rd party controllers. 

[Rafael acevedo]

The parachute in ksp has a 5 to 1 glide ratio, which is about as high as current technology allows. The problem has to do with forward speed. If you time it really well, you can land at 0/0 very hard to do. In ksp you might do between 5 to 10 mps landings  which leaves you with a forward speed of up to 22 mph (survivable for a Kerbal, but very doubtful for a human) , a parachute forward speed is determined by wing loading (same as with a gliding airplane). The issue is that we have an overloaded wing ( a wing to small for the weight it is carrying).  If KSP uses wing loading calculations for its simulations, what we need to do is increase the size of the wing. However that assumes that kerbals now has mass, they have been essentially massless thought all previous iterations, which is why I think the fwd speed was determined before hand.

[Gargamel]

1 hour ago, Rafael acevedo said:

However that assumes that kerbals now has mass, they have been essentially massless thought all previous iterations, which is why I think the fwd speed was determined before hand.

Hmmm....  I know mods that introduced chutes to kerbals previously would have to calculate the mass of the kerbal, else the chute wouldn't do anything.  And a massless kerbal wouldn't be attracted by gravity. 

From the Wiki:

Quote

Kerbals display no variance in height or weight. They stand roughly 0.75 meters tall (2'5½"). A Kerbal in an EVA suit has a mass of 93.75 kilograms (206.68 lb.), which is 0.09375 in-game Mass units. However, this only counts toward the mass of a craft if seated in an EAS-1 External Command Seat; Kerbals add no mass when in a command pod or PPD-10 Hitchhiker Storage Container or the Mobile Processing Lab MPL-LG-2.

Since the ECS was considered to be EVA, I think the kerbals always had mass. 

[Rafael acevedo]

Thx for the info on kerbal mass

From the info on Kerbal Mass and assuming a wing loading of 1 the parachute should be about 206 square feet. ( the minimum survivable is 135 Sq Ft ).  there are other considerations, but this gives an useful approximation for a forgiving parachute. 

Edited March 19, 2018 by Rafael acevedo

[Zeiss Ikon]

5 hours ago, Rafael acevedo said:

assuming a wing loading of 1

Took me a second to back out your "wing loading of 1" being in lb/ft^2.  In game, that'd be 4.88 kg/m^2 or, if we fix the mass vs. force units, 47.9 N/m^2.

Of course, the canopy is animated as being quite a bit smaller than that; relative to Kerbal size (.75 m tall); it looks like about half that area, if not a bit less.