Agility and the CT manuever drive
- Thread starter Spankstinator
- Start date
“..But only with a good trajectory to space and with the atmosphere significantly thinner.”
Point the nose straight up, acc. at 2Gs to 1000kph and have the computer kick up the speed as the air thins out.
At 7,000m you are at ½ atmosphere so you can go 2000kph?
At 9,000m you have ¼ atmo. so you can go 4000kph?
So even at 1000kph you will be up and away in a matter of minutes if you can increase your speed as the atmosphere thins out.
"Without control surfaces, you're just flying a bullet."
Sometimes you need to become one in order to avoid one!
Point the nose straight up, acc. at 2Gs to 1000kph and have the computer kick up the speed as the air thins out.
At 7,000m you are at ½ atmosphere so you can go 2000kph?
At 9,000m you have ¼ atmo. so you can go 4000kph?
So even at 1000kph you will be up and away in a matter of minutes if you can increase your speed as the atmosphere thins out.
"Without control surfaces, you're just flying a bullet."
Sometimes you need to become one in order to avoid one!
Andrew Boulton
The Adminator
"Without control surfaces, you're just flying a bullet."
Like I said, only if you're just running away.
Like I said, only if you're just running away.
rhoneycutt
SOC-11
sorry, but I've been busy and couldn't find my notes..anyways, here's how I deal with airspeed...
---------------------------------------------------
First, it is assumed that you know the basic dimensions of the ship, enough to have a good idea of frontal surface area. Exact measurements aren't really neccessary as this only give a rough estimate anyways. Just get somewhere in the ballpark.
Determine if the ship is streamlined, partially-streamlined, or unstreamlined. Streamlined means that the ship is rounded/pointed both for and aft ( like a P-51 mustang ). Partially-streamlined means rounded/pointed either for or aft, but not both ( Like a bullet or P-47 ). Unstreamlined is blunt for and aft ( like a shoebox ). This gives a base drag coefficient.
Streamlined Cd = .2 which is close to what Eiffel measured for a sphere.
Partially-streamlined Cd = .5 which is close to drag for a hemishpere, rounded side forward.
Unstreamlined Cd = 1.2 which is close to drag of a bluff body ( flat plate )
The actual Cd of the ship is (base Cd)/(finenss ratio)^.5
The fineness ratio is the length divided by the height or width, whichever is greater.
drag = dens/2*Cd*frontal area*speed^2
so now, we take the air's density ( from atmo type and altitude ) and the final Cd and the thrust of the engines ( newtons ) and plug them all in the drag equation to find the maximum speed possible which is where total thrust equals total drag. This does not take heating into account for max speed.
if thrust(g's) is g's*9.81*ships mass, then
max speed= sqrt( (thrust *9.81*ship_mass)*Cd*front_area*atm_dens/2)
this was done from memory, but I hope I didn't screw it up. This was taken from an aerodynamics textbook written just after WW2.
Anyways..this is the basic idea on how I do things.
oh..Airframe IMTU only means that the ship can manuever with aero controls as opposed to being like an arrow.
Airframe is seperate from streamlining. A 1913 Voisin bomber is an airframe but unstreamlined.
High tech ships can use base bleed, slats, suction slots, etc and other aero trips to be streamlined without looking like it. All you got to do is pay the cost at construction.
A neat thing to do is roll a task for the design team for the Cd ( as in the back of Starship Handbook ) to see if the design is good or not, but noone will know for sure until a prototype is built and flown. Test pilot adventure hook?
thats all for now.
---------------------------------------------------
First, it is assumed that you know the basic dimensions of the ship, enough to have a good idea of frontal surface area. Exact measurements aren't really neccessary as this only give a rough estimate anyways. Just get somewhere in the ballpark.
Determine if the ship is streamlined, partially-streamlined, or unstreamlined. Streamlined means that the ship is rounded/pointed both for and aft ( like a P-51 mustang ). Partially-streamlined means rounded/pointed either for or aft, but not both ( Like a bullet or P-47 ). Unstreamlined is blunt for and aft ( like a shoebox ). This gives a base drag coefficient.
Streamlined Cd = .2 which is close to what Eiffel measured for a sphere.
Partially-streamlined Cd = .5 which is close to drag for a hemishpere, rounded side forward.
Unstreamlined Cd = 1.2 which is close to drag of a bluff body ( flat plate )
The actual Cd of the ship is (base Cd)/(finenss ratio)^.5
The fineness ratio is the length divided by the height or width, whichever is greater.
drag = dens/2*Cd*frontal area*speed^2
so now, we take the air's density ( from atmo type and altitude ) and the final Cd and the thrust of the engines ( newtons ) and plug them all in the drag equation to find the maximum speed possible which is where total thrust equals total drag. This does not take heating into account for max speed.
if thrust(g's) is g's*9.81*ships mass, then
max speed= sqrt( (thrust *9.81*ship_mass)*Cd*front_area*atm_dens/2)
this was done from memory, but I hope I didn't screw it up. This was taken from an aerodynamics textbook written just after WW2.
Anyways..this is the basic idea on how I do things.
oh..Airframe IMTU only means that the ship can manuever with aero controls as opposed to being like an arrow.
Airframe is seperate from streamlining. A 1913 Voisin bomber is an airframe but unstreamlined.
High tech ships can use base bleed, slats, suction slots, etc and other aero trips to be streamlined without looking like it. All you got to do is pay the cost at construction.
A neat thing to do is roll a task for the design team for the Cd ( as in the back of Starship Handbook ) to see if the design is good or not, but noone will know for sure until a prototype is built and flown. Test pilot adventure hook?
thats all for now.
rhoneycutt
SOC-11
woops...
Cd = base Cd/(length/min(height,width))
Cd = base Cd/(length/min(height,width))
rhoneycutt
SOC-11
Eff it!
I'll get it right this time!
Cd=base_Cd/(length/(min(height,width))^.5)
I'll get it right this time!
Cd=base_Cd/(length/(min(height,width))^.5)
rhoneycutt
SOC-11
Eff it!
I'll get it right this time!
Cd=base_Cd/(length/(min(height,width))^.5)
I'll get it right this time!
Cd=base_Cd/(length/(min(height,width))^.5)
Fritz_Brown
Super Moderator
As somebody previously mentioned atmospheric heating (Kurega), I will ask this question (thread hijack in progress, remain calm and noone gets hurt):
What would atmospheric heating do to weapons?
If you're talking about accelerating at 3G and screaming along at hypersonic speeds, what would that do to, say, a laser? I'm not talking about melting the weapon mount, but the beam itself. I would think the bow wave and any plasma would seriously degrade a laser's effectiveness. IMO, firing a plasma or fusion weapon would be suicidal. How might it affect Meson weapons?
What would atmospheric heating do to weapons?
If you're talking about accelerating at 3G and screaming along at hypersonic speeds, what would that do to, say, a laser? I'm not talking about melting the weapon mount, but the beam itself. I would think the bow wave and any plasma would seriously degrade a laser's effectiveness. IMO, firing a plasma or fusion weapon would be suicidal. How might it affect Meson weapons?
“OK let’s everybody just relax, I am just reaching for my reply . . .don’t get all twitchy on me.” he said with his hands in the air.
I don’t know enough about physics but my gut reaction is that X-ray lasers, and meson weapons would be unaffected or the effects could be mitigated by computer control.
Optical lasers would be a different story I am sure.
The odd thing is that at mach 10 like the X-43 the atmosphere is soooooo thin. What I mean is that if you are using 6g reactionless thrusters you are up and out of the atmosphere in seconds. If you want to fire at a moving target at 2000m moving at a modest mach 5 just skip up to 50km and you are good to fire. At 11,000 km/h+ 50km is nothing. Traveller fighters are in a class so far removed from our TL7 stuff that it is like comparing a Sopwith Camel to an F-22. Hell the thing would probably not even show up on radar.
Hypersonic Stuff
Not sure if this helps but it has pictures.
I don’t know enough about physics but my gut reaction is that X-ray lasers, and meson weapons would be unaffected or the effects could be mitigated by computer control.
Optical lasers would be a different story I am sure.
The odd thing is that at mach 10 like the X-43 the atmosphere is soooooo thin. What I mean is that if you are using 6g reactionless thrusters you are up and out of the atmosphere in seconds. If you want to fire at a moving target at 2000m moving at a modest mach 5 just skip up to 50km and you are good to fire. At 11,000 km/h+ 50km is nothing. Traveller fighters are in a class so far removed from our TL7 stuff that it is like comparing a Sopwith Camel to an F-22. Hell the thing would probably not even show up on radar.
Hypersonic Stuff
Not sure if this helps but it has pictures.
Fritz_Brown
Super Moderator
Good thought about going to orbit, Kurega.
Though, I would think even X-ray lasers would be at least minimally affected by air gradients, etc.
Though, I would think even X-ray lasers would be at least minimally affected by air gradients, etc.
Come to think of it all of that hypersonic turbulence could act like a shield for the fighter. The entropy layer disperses energy IIRC. Soooooo at mach 12 that laser beam must pass through this layer and the shock wave. Your beam weapons might be less effective but so are the enemy’s. Missiles designed for space warfare might a have bit of trouble dealing with all of the swirling air and the shockwave too.
X-rays might be affected more if there was hydrogen (like in a gas giant) or lots of water vapor (earth).
I still think that the only thing that would stop a meson gun is a meson screen.
X-rays might be affected more if there was hydrogen (like in a gas giant) or lots of water vapor (earth).
I still think that the only thing that would stop a meson gun is a meson screen.
mike wightman
SOC-14 10K
Hmm, so the shock wave is acting as a barrier, much like a plasma?
Another chance to post this link.
Another chance to post this link.
So the air is forced into a plasma state and acts like a shield Hmmmm . . .
Dipping into an atmosphere could be a very effective defensive tactic for COACC craft.
Depending on your speed and altitude you might be able to hide from ship fired missiles as they try to catch you. The standard space missile might be able to take the heat for awhile but prolonged exposure to hypersonic turbulence and heating might just cause it to crack up.
Dive to 8000m and then pull up hard to 9000m. Scream along at mach 15 until the missile goes BOOM.
Dipping into an atmosphere could be a very effective defensive tactic for COACC craft.
Depending on your speed and altitude you might be able to hide from ship fired missiles as they try to catch you. The standard space missile might be able to take the heat for awhile but prolonged exposure to hypersonic turbulence and heating might just cause it to crack up.
Dive to 8000m and then pull up hard to 9000m. Scream along at mach 15 until the missile goes BOOM.
Andrew Boulton
The Adminator
Unless it's a nuke, in which case the shockwave will swat you like a fly.
Fritz, I found another one last night, by accident.
Lasers won't work at Traveller ranges unless there's "gravitic focusing" going on. Apparently starship lasers have to shoot a beam of gravitonlike thingies along with the laser, which pull the laser light into a beam that stays coherent at our typical ranges.
That's in FFS1 and FFS2. The equations are annoying, but no worse than anything else in those books. How's that for handwavium?
These gravitic handwaves are useful because they allow effects that are fun in the game, or ease up on the referee's job, or both.
Suffice it to say that gravitics is as important as jump for Traveller. I was stunned to realize this.
I suspect there's a Grand Unification Theory of Gravitics behind these outward phenomena. I'm trying to cook one up. Something that relates masses, tech level, energy input, and force output in a way that's friendly to maneuver drive, artificial gravity, lifters, acceleration compensation, and gravitic focusing. Now there's a tall order.
mike wightman
SOC-14 10K
There's a couple of ways round grav focussing for lasers.
Reduce the scale for ship combat.
Or assume ship mounted lasers start off as x-ray lasers, becoming gamma ray lasers at higher TLs.
I still don't see how plasma and fusion guns can function as described in a vacuum
Reduce the scale for ship combat.
Or assume ship mounted lasers start off as x-ray lasers, becoming gamma ray lasers at higher TLs.
I still don't see how plasma and fusion guns can function as described in a vacuum
far-trader
SOC-14 10K
We just keep telling them all that plasma and fusion weapons involve munitions until it is canon
I wondered about the ranges for X-Ray lasers.
I've also been thinking Fire, Fusion, and Steel is waay too conservative with their estimates for useful Xray lasers.
Seems to me that we've had prototype X-Ray lasers for 20+ years now. Granted, that means TL8 doesn't have them, but I can't see why TL9 can't. Heck, the laser has only been around for fifty years or so, and it (the non-x-ray laser) is just about ready for ground-based atmospheric combat. 50 years hence, why shouldn't we have production x-ray lasers?
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