Agility and the CT manuever drive

[far-trader]

In my TU the artificial gravity and inertial compensators are tied directly to the maneuver drive field. It is a field effect based on the hull so everything inside the hull has an identical force acting on it, generally 1G "down" and cancel of all vectors generated by the maneuver drive. Loose the M drive you loose the field effects. Get hit (or hit something) and you feel it (vector change not compensted) proportionate to the impact. The "down" is decided upon design and can't be (easily) changed after the hull is laid. There is only one "down" within a hull. The strength of the AG is fixed and also not easily changed, and can only be changed for the whole ship. The change is also not fast, taking several seconds to go from one level of G to the next at the fastest (such as power or drive loss).

The same field is what is also commonly called the jump grid, which actually while important for maintaining the jump coccoon is primarily for the AG and IC effects. This is where your power is gettting used once you are actually in jump space. In jump space if your jump drive fails so does the AG and IC, though your main worry is that the jump space starts shrinking in on your hull, which will kill you quicker than the worry about being weightless.

 

[mike wightman]

IMTU the maneuver drive reduces the inertial mass of the ship so that a small plasma rocket or ion drive can move the ship.
The maneuver drive also includes null grav modules to provide lift on planets.

The acceleration compensators are linked to the maneuver drive so they know what to expect.
"Get hit (or hit something) and you feel it (vector change not compensted) proportionate to the impact" is how I do it too

 

[Tobias]

Originally posted by Fritz88:
Tobias, a F-15E will accelerate going straight up - so I know some have a >1G accel. (Course, that's slick....)

Yes, it will - barely, and it depends on the loadout. Some planes have this capability to "stand on their exhaust", others don't. Of course, a lot depends on the load carried.
It is really just a simple matter of whether thrust exceeds weight. For an F-15E, with a moderate loadout, this is the case.

Regards,

Tobias

 

[Fritz_Brown]

Actually, Dan, some aircraft can accelerate upwards till they reach their max speed (aerodynamically), or they run out of air or gas. This isn't a hugely beneficial feature in most cases (compared to the trade-offs), so most aircraft do with a 1:1 thrust ratio - as long as you can maintain your speed going straight up, you're good enough.

Dan (and Sigg), do you then assume the IC essentially isolates you (relativistically) from the universe in which the drive is acting?

 

[mike wightman]

Fritz, IMTU the effects of relativity still rear their ugly heads when speeds get up to high enough percentages of c.

I'm too big a fan of "The Forever War" to have it any other way

 

[Fritz_Brown]

Sorry, Sigg, I should have said "newtonianly" (?)
I mean separating the effects of acceleration from the interior of the ship....

 

[mike wightman]

Ahh, ok.

No, IMTU the inertial mass reduction field generated by the maneuver drive reduces the mass of the ship so that the puny reaction drives can push at 1-6G depending on the field mass reduction effect.

The acceleration compensators are a separate system that use repulsor like fields to mitigate the effects of high acceleration and lateral G forces during turns - they operate within the ship, but don't disconnect the ship in any way from real space.

 

[parmasson]

By Shere Khan
“airspeed is limited by atmospheric heating.”

Is it? My 100 ton Scout does not seem to have any problem on reentry even on size 10 worlds with dense atmospheres. In addition it can skim hydrogen from GGs at enormous speeds. Just how hot does the hull get on reentry and would that not mean that the ship had the ability to go at least that fast? I am sure that eventually the resistance would build up but could not our hypothetical S class reach mach 6 or 7 with the ability to accelerate at 2Gs and damn good heat shielding?

 

[Andrew Boulton]

Who says landing or skimming requires supersonic speeds?

MT says a Type-S has a top speed of 1000km/h. TNE increases that to 1100km/h, but that's still less than Mach 1.

 

[Fritz_Brown]

Actually, depending on altitude, that's just at Mach 1. And, there might be real issues with taking a large craft supersonic - depending on shape, etc. But, if it can't go supersonic, how is it going to re-enter atmosphere? I still have a hard time with the idea that you can just slide into the atmosphere at something other than orbital speed - maybe it's just my $.20 (you know, a pair o' dimes).

Edit: Of course, I guess going supersonic is not neccessarily the same thing as slamming into the atmosphere and slowing from hypersonic speeds. end edit

 

[parmasson]

So a 1960s Soyuz capsule has better heat shielding than Traveller starships?

 

[parmasson]

“MT says a Type-S has a top speed of 1000km/h. TNE increases that to 1100km/h, but that's still less than Mach 1.”

Could it be a misprint? Could they really mean 10,000 km/h? there have been mistakes before.

 

[robject]

That sounds familiar. But maybe I'm thinking of the grav speeder.

If it's in MT and TNE, then it doesn't seem likely to be a misprint.

I suppose the limit is there so that Travellers can't just zip to any part of the globe they like without any perceivable delay.

 

[Tobias]

In MT, there were the three streamlining levels of "Unstreamlined", "Streamlined" and "Airframe", with respective maximum speeds of 300 kph, 1000 kph and whateveryourenginesputout kph.
I would argue that this applies to level atmospheric flight at low altitudes in a standard atmosphere and should increase at higher altitudes/in thinner atmospheres.
The limiting factor is likely not heating (anything that can so easily survive reentry is not gonna have any problems with that) but control. With less than optimal streamlining, the craft will lose control at high speed because of turbulences.
That said, the type S should have been "airframe". The three streamlining levels above should correspond to the Unstreamlined, Partially streamlined and Streamlined levels of HG, which means all atmosphere-capable ships should have had "Airframe".

Regards,

Tobias

 

[parmasson]

The limiting factor is likely not heating (anything that can so easily survive reentry is not gonna have any problems with that) but control. With less than optimal streamlining, the craft will lose control at high speed because of turbulences.

OK I think I can live with that in game terms but it is still hard to believe.

 

[rhoneycutt]

atmospheric heating is the limiter of speed.

above a certain temp ( I forget...above 3500K? ) physical matter does not exist in its solid state.

alblative panels are used in those cases.
the shuttle ( which does not have to maintain speeds ) uses hi drag to slow as quickly as possible in the thinner upper atmosphere to a speed that does not result in destruction. Such speed in the lower atmosphere would vaporize it.

At mach 6.7 or so, the X-15 had a titanium pylon sliced off by the shockwave as cleanly as a plasma torch and the stresses caused that fuselage to be scrapped.

An interesting exercise is to work out the actual drag in various atmospheres and find out where the drag is equal to the thrust...that is maximum speed, even if you don't bother with flaming reentries.

I posted my ideas on figuring drag coeffients for ships on the TML a couple of years ago...I'll rewrite them and post them somewhere if there is interest.

 

[mike wightman]

Originally posted by Shere Khan:
I posted my ideas on figuring drag coeffients for ships on the TML a couple of years ago...I'll rewrite them and post them somewhere if there is interest.

Please do, I'd like to see them

 

[parmasson]

So the real limit here is the speed of sound?

My S class is not rated for supersonic, period. My max speed of 1000kph is at 1 atmosphere. As I attempt to escape the starport I quickly reach 1000kph (2g accl. right?) and as the atmosphere thins out I pick up speed until I reach escape velocity in the upper atmosphere. Hopefully I reach my jump point before those SDBs catch up.

 

[Tobias]

Originally posted by Shere Khan:
atmospheric heating is the limiter of speed.

At the speeds we are talking about here (~1000 kph)? No. Certainly there is a limit due to heating, but not at this level. 3500K seems a bit low in any case. There are some materials which I know to have a higher melting point.

Regards,

Tobias

 

[Andrew Boulton]

"So the real limit here is the speed of sound?"

For non-airframe hulls, yes.

The Type S is fairly streamlined, so if you're just running away I'd probably let a decent pilot risk going supersonic.