Terminal Velocity modeled?

[Jona33]

Hi guys, I was doing refueling practise when I disconnect (as usual:mad:) and crash into the tankers boom. The planes on fire so I immediately punch out, I was at 18,000 feet when this happened and I sat in the seat till 16'000ish and then opened my parachute and all the rest. I noticed that in the seat I was doing 300 knots. I don't understand much about Terminal velocity but shouldn't I be unable to fall faster than 120 (Is that right). I ejected from 39,000 once and was doing 600 knots by the time I opened my parachute.:helpsmilie:

 

Thanks.

[Nate--IRL--]

Was that ground speed or airspeed?

 

Nate

[Jona33]

Not sure, just on the infobar in the F2 view.

[Speed]

First of all, make sure that those were really knots. The default may be metric, in which case those would have been kilometers an hour.

 

Secondly, terminal velocity is not some magic number at 120 mph. 120 mph tends to be the terminal velocity of a human being. Terminal velocity is just the velocity where the force of drag equals the force of gravity, and so a free falling object cannot accelerate any faster than that. For denser and/or more aerodynamic objects, it's going to be much higher than 120 mph. For lighter, less aerodynamic objects, it will be less. For example, the terminal velocity of a feather is like walking speed.

[Jona33]

First of all, make sure that those were really knots. The default may be metric, in which case those would have been kilometers an hour.

 

Secondly, terminal velocity is not some magic number at 120 mph. 120 mph tends to be the terminal velocity of a human being. Terminal velocity is just the velocity where the force of drag equals the force of gravity, and so a free falling object cannot accelerate any faster than that. For denser and/or more aerodynamic objects, it's going to be much higher than 120 mph. For lighter, less aerodynamic objects, it will be less. For example, the terminal velocity of a feather is like walking speed.

 

Would probably explain it, and remind me to pay attention in physics:lol:. I guess a massive ejector seat is going to weigh a fair bit.

[XarBat]

Drag seems to not be modeled for pilots. I don't think drag is modeled well for Mavericks. I have used the F7 key and seen Mavericks going Mach 2 close to the ground with their rockets turned off. It looked like it was modeled for bullets in Black Shark. When firing at something 3-4km away, the bullets seemed to much more lazily fall on to the ground then firing at something closer.

[LostOblivion]

Mavs are not fully ballistic, since they use their fins to counter bending of trajectory.

[Inseckt]

I dont know if the effect would be unneglisheable, but terminal velocity varies with height. At great heights, terminal velocity is greater due to the less dense air, and thus less air resistance. As I said, I dont know how big the discrepancy would be. Another thing wich I know DO greatly affect T.V. is the position in wich you are falling. If you were seated in a upright position in relation to the ground, your speed would be greater then if you were falling, for instance, with your back first.

[lubey]

Still, at high altitude 600 knots is supersonic and personally I doubt a free-falling pilot in ejector seat could ever break the sound barrier. In fact when a martin baker ejection seat is ejected from a supersonic aircraft, sensors onboard the seat do not allow automatic deployment of the parachute until it has slowed down to below mach 1 by itself, otherwise the parachute would kill the pilot due to such immense deceleration.

[andysim]

even the apollo capsules on thier way back to earth slowed right down on thier own before any chutes, just the friction of the ever more dense air was all they needed.

[EtherealN]

Still, at high altitude 600 knots is supersonic

 

First off, the infobar is not IAS, it is TAS (well, ground speed might be the best way to describe it, but not strictly true either due to the vertical). It also defaults to km/h. :)

(See, we who know which system is the superior one has to make things fun for all naughty imperalists. :D )

 

The easiest way to settle this is a track. No point bandying numbers around when we can actually look at the same thing. :)

[Jona33]

I'll get a track Ethereal. Learnt more here than I ever did in physics though :)

 

EDIT: Got one here.Terminal Velocity.trk

Edited October 29, 2011 by Jona33

[EtherealN]

Study Simulators have a habit of doing that. :D

 

I'll check it out as soon as I get a moment. :)

[lubey]

First off, the infobar is not IAS, it is TAS (well, ground speed might be the best way to describe it, but not strictly true either due to the vertical). It also defaults to km/h. :)

 

Point taken. But the speed of sound is still 573 knots (TAS) at 20,000 ft (according to wikipedia anyway :unsure:).

[EtherealN]

lubey, read the second sentence in the part you quoted. ;)

[EtherealN]

I'll get a track Ethereal. Learnt more here than I ever did in physics though :)

 

EDIT: Got one here.[ATTACH]58120[/ATTACH]

 

Checked the track now, and yeah... There is something weird going on there. There definitely is drag modeling (it starts aerobraking at the 600 mark, and altitude also affects vertical velocity once shute deploys), but I can confirm that it does indeed appear that it was knots you saw. (I explicitly set mine to do knots and got the same numbers.)

 

But well, the human flight model (in the literal sense :D ) is still SFM, so to spak, and I guess it hasn't been tweaked. It isn't strictly necessary, after all.

 

I would hazard the guess that there's a pretty rudimentary LUA table somewhere that could be tweaked, but I'm not sure if I consider it worth the effort.

[JaBoG32_Prinzartus]

Still, at high altitude 600 knots is supersonic and personally I doubt a free-falling pilot in ejector seat could ever break the sound barrier. In fact when a martin baker ejection seat is ejected from a supersonic aircraft, sensors onboard the seat do not allow automatic deployment of the parachute until it has slowed down to below mach 1 by itself, otherwise the parachute would kill the pilot due to such immense deceleration.

 

Investigate on "Joseph Kittinger", he did break the sound barrier in free fall IRC.

He did it by jumping from a weather baloon. So it is possible under very special

circumstances. But back to topic.

Edited October 29, 2011 by JaBoG32_Prinzartus

[Jona33]

Checked the track now, and yeah... There is something weird going on there. There definitely is drag modeling (it starts aerobraking at the 600 mark, and altitude also affects vertical velocity once chute deploys), but I can confirm that it does indeed appear that it was knots you saw. (I explicitly set mine to do knots and got the same numbers.)

 

But well, the human flight model (in the literal sense :D ) is still SFM, so to speak, and I guess it hasn't been tweaked. It isn't strictly necessary, after all.

 

I would hazard the guess that there's a pretty rudimentary LUA table somewhere that could be tweaked, but I'm not sure if I consider it worth the effort.

 

Yeah, I was only wondering. I just seem to spend a lot of time falling through space. Enemy fighters are.....:P

[Smokin Hole]

... I guess a massive ejector seat is going to weigh a fair bit.

 

Didn't Galileo have something to say about this?

[EtherealN]

Not really, Smokin, he didn't.

 

What he found was that bodies accelerate at the same speed regardless of weight, but this in and of itself is not relevant here. Terminal Velocity, as already mentioned, is the velocity at the point where drag is equally powerful as gravity, causing the body to no longer accelerate. However, when you make something more dense, you need more speed before drag will reach an equilibrium with gravity.

 

Again, as mentioned, you can test this very easily: take a steel sphere in one hand, and a feather in the other, and drop them simultaneously. If there was no atmosphere, they would fall at the same speed (this has been done on the moon as well, as one of the publicity gigs they did while up there), but on earth - with it's atmosphere - you will very quickly see that they have different terminal velocity.

[Inseckt]

yeah, galileos law of free falling objects is about objects in a vacuum. There was a mention erlier in this thread about paying attention in physics:)

[Speed]

yeah, galileos law of free falling objects is about objects in a vacuum. There was a mention erlier in this thread about paying attention in physics:)

 

Yea, reminds me of one of those IQ tests they give you as a kid. The lady had been asking questions with fairly short answers, then gets to this one where she listed like 12 objects to be dropped off the top of a building simultaneously, and wanted me to list in order when they hit the ground. I was like, "Are you serious?!?!", then I told her to surround the building in a big airless chamber, and then all 12 would hit the ground at the same time. Pretty sure I got that one wrong :D

[LostOblivion]

Yea, reminds me of one of those IQ tests they give you as a kid. The lady had been asking questions with fairly short answers, then gets to this one where she listed like 12 objects to be dropped off the top of a building simultaneously, and wanted me to list in order when they hit the ground. I was like, "Are you serious?!?!", then I told her to surround the building in a big airless chamber, and then all 12 would hit the ground at the same time. Pretty sure I got that one wrong :D

 

Yeah, it is terrible how many tests assume things. I mean, you cannot naturally assume the building is not locked inside a big vacuum globe, can you? :P