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Old 08-06-2015, 06:18 AM   #11
vicky_molokh
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Default Re: Reentry with Flight/TK

Quote:
Originally Posted by Terwin View Post
At what altitude/atmospheric density would you cap flight without Space Flight?
The ISS experiences enough drag to need orbital boosts even above 200 miles, but I don't think I would let a character without +Space use flight to maneuver on EVA for example.
That's a hard question. At whatever altitude/density at which Space Flight Only stops working too, definitely. Space Flight Only warns that it makes the character incapable of reentry, so I'd rule that the line is drawn at whatever point at which 'reentry' is a thing (including reentry hazards).

Of course, this is an ugly answer to a question about painfully binary states, describing a phenomenon that is not exactly binary IRL.
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Old 08-06-2015, 08:23 AM   #12
Anaraxes
 
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Default Re: Reentry with Flight/TK

Any character with enough TK to hold themselves off the ground could slow themselves in orbit, while maintaining altitude, and then lower straight down. That just requires devoting more of your "thrust" to maintaining altitude rather than deceleration as you slow -- pulling at a varying angle, that is. Chemical rockets don't do that because it would take too much fuel; the heat shield for reentry weighs less.

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Originally Posted by Terwin View Post
At what altitude/atmospheric density would you cap flight without Space Flight?
The conventional definition for "space" is 100 km. This is about the altitude of the top of the mesosphere. I think the USAF still sticks to 50 miles. As you say, the height for maintaining an orbit without propulsion is a bit higher. If you want to take someone "out to the black" -- visually, that is, so the sky looks black -- that's around 100 miles / 160 km.
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Old 08-07-2015, 12:06 AM   #13
CeeDub
 
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Default Re: Reentry with Flight/TK

I remember Kromm saying that for TK, an objects frame of reference is itself. IN the example he gave, if you drove past a resting (with reference to the planet's surface) object in a car going Move 40 and your TK ST was 10, you could still only accelerate that object to Move 10, in any direction, including the direction your car was going. Conversely, if you were "standing still" (see above) and an object were to move through your TK range with Move 40, you could decelerate it to Move 30 (still assuming TK ST 10) or accelerate it sideways with Move 10, but not accelerate it further in the direction it's already going in. The RAW say that TK is capable of short bursts of force that enables the character to "throw" things at higher speeds and beyond his range, but neither the RAW nor Kromm were any more specific than that, other that your TK ST still being the deciding factor.

This is actually a problem with TK I've stumbled on before. For any consideration that involves actual physics (as far as that makes sense for obviously supernatural powers), you'd need the acceleration you can apply to a given mass. At least that's what my rather limited memory of high school physics tells me. TK ST gives us the mass, but only the speed (about 2.1 meters/second (1.8 meters tall person lifting an object overhead in one second, as described for Basic Lift (B15))). I assume that is not even the top speed, since the distance of 2.1 meters and the time of one second also includes acceleration from zero and deceleration back to zero.

Hm, now that I think of it... Maybe one can work something out with the different Encumberance levels. Don't know if my Physics Fu is strong enough for that, assuming that idea isn't totally useless altogether. Will try to apply some brain to it this evening, gotta make my Job Roll.

Last edited by CeeDub; 08-07-2015 at 12:08 AM. Reason: typos
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Old 08-07-2015, 12:12 AM   #14
vicky_molokh
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Default Re: Reentry with Flight/TK

Quote:
Originally Posted by CeeDub View Post
This is actually a problem with TK I've stumbled on before. For any consideration that involves actual physics (as far as that makes sense for obviously supernatural powers), you'd need the acceleration you can apply to a given mass. At least that's what my rather limited memory of high school physics tells me. TK ST gives us the mass, but only the speed (about 2.1 meters/second (1.8 meters tall person lifting an object overhead in one second, as described for Basic Lift (B15))). I assume that is not even the top speed, since the distance of 2.1 meters and the time of one second also includes acceleration from zero and deceleration back to zero.

Hm, now that I think of it... Maybe one can work something out with the different Encumberance levels. Don't know if my Physics Fu is strong enough for that, assuming that idea isn't totally useless altogether. Will try to apply some brain to it this evening, gotta make my Job Roll.
Your acceleration of a controlled object is equal to your TK Move for subsequent turns, and something like double that in the first second: you achieve top speed in one turn and move the object up to your TK Move yards.
For uncontrolled velocities (when you accelerate the object as you release it in the desired direction), use the Throwing rules, just like you do when providing a burst of acceleration to a dart with your hand (that happens to also be in excess of your Move!).
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Old 08-07-2015, 01:50 AM   #15
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Default Re: Reentry with Flight/TK

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Originally Posted by vicky_molokh View Post
Your acceleration of a controlled object is equal to your TK Move for subsequent turns, and something like double that in the first second: you achieve top speed in one turn and move the object up to your TK Move yards.
Sounds too good to be true, TBH. Being able to accelerate a controlled object by TK ST = m/s sounds good and reasonable because the acceleration is limited by the TK's range. But what about TK levitation? If I'm controlling myself, I'm never out of range and could accelerate to unlimited speed. In theory. Air resistance and friction would become a problem to a character without DR rather quickly, but even the most incompetent munchkin could come up with a build that includes DR and heat resistance for fewer CP than what infinite levels of Enhanced Move (Air) would cost.

That is, of course, if you really meant that the acceleration (not the speed) for subsequent turns is TK Move. Or unless I misuderstood you really badly.
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Old 08-07-2015, 02:10 AM   #16
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Default Re: Reentry with Flight/TK

Quote:
Originally Posted by CeeDub View Post
Sounds too good to be true, TBH. Being able to accelerate a controlled object by TK ST = m/s sounds good and reasonable because the acceleration is limited by the TK's range. But what about TK levitation? If I'm controlling myself, I'm never out of range and could accelerate to unlimited speed.
No. Please read up on the trait write-up:
"You can move
any object you have strength enough
to lift, at a Move equal to your TK
level
, modified as usual for encum-
brance level (see Encumbrance and
Move, p. 17)"
You can only move objects relative to the relevant reference frame at up to TK y/s, but you can accelerate them up to this velocity quite fast. If your reference frame is yourself, you cannot accelerate yourself because you are always at rest relative to yourself. So when moving yourself, you have to deal with some other reference frame than yourself.

Quote:
Originally Posted by CeeDub View Post
In theory. Air resistance and friction would become a problem to a character without DR rather quickly, but even the most incompetent munchkin could come up with a build that includes DR and heat resistance for fewer CP than what infinite levels of Enhanced Move (Air) would cost.
Note that a vehicle's or character's rated air move is after factoring in air resistance, weight of one's body etc.

Quote:
Originally Posted by CeeDub View Post
That is, of course, if you really meant that the acceleration (not the speed) for subsequent turns is TK Move. Or unless I misuderstood you really badly.
You can Move up to your TK Move (which is your TK Level) per turn. In any given turn, you are free to accelerate up to your Move. You can spend another turn to accelerate to a Sprint (in a straight line).
High acceleration does not automatically assume unlimited velocity.
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Old 08-07-2015, 04:59 AM   #17
CeeDub
 
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Default Re: Reentry with Flight/TK

Quote:
Originally Posted by vicky_molokh View Post
You can Move up to your TK Move (which is your TK Level) per turn. In any given turn, you are free to accelerate up to your Move.
I see, so you meant "speed", not "acceleration", i.e. you accelerate from zero to TK Move (with faster actual acceleration that declines towards the objects "terminal" speed (TK Move)) and in subsequent turns, you do not actually accelerate (in the physical sense) any more (except to counteract gravity and air resistance), you just effectively maintain that speed. That's also what I understood from the RAW about TK.

The "problem" is that it uses an inconsistent frame of reference. If I levitate on a moving train, I float through the passenger compartment at TK Move in any direction instead of taking collision damage from instantly crashing into the rear compartment wall (I move at TK Move, the train moves a lot faster).

If I move an object outside the train (resting at Move 0), the object's position on the planet's surface is its frame of reference, meaning I can cause a one-time change in speed of TK Move in any direction and maintain that for as long as I'm in range. The same applies if I move myself.

The thing is that physics don't actually work that way. (The obvious answer is, of course "Duh! You can't really move stuff with your mind, it's a game of make-believe!") As far as I understand, you'd apply a certain amount of Force (which is mass * acceleration) to an object, and its mass then determines its acceleration. If you were to continue to apply the same amount of Force, acceleration would continue at the same rate (if it weren't for gravity and air resistance). Frex, you should be able to move (and accelerate) an object faster horizontally than straight up. The RAW partially reflect this in that you can shove or slighty shift an object of higher mass than you could lift with two hands.

In the vast majority of uses in the game, the RAW are totally sufficient and balanced as game mechanics. Only when you try to reenter a planet's atmosphere with TK (or try to use TK to push yourself along on a bicycle, which is how I got to thinking about this), the mechanics stop making sense.

The easiest solution is to have the GM make a judgement call, taking into consideration the campaign's intended realism and/or how much having PCs burning up in the atmosphere moves the plot along.

On the other hand, I think it'd be really interesting and neat to try and work this out. Unfortunately, my Physics Fu is weak and brings shame on my family.
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