FFW doing it my way

[phavoc]

Which therefore doesn't apply.

Look at the flow chart for ship construction on page 34:

"4.Determine fuel tankage (blocks 29a, 29b) requirements. p. 29
A. Consider L·Hyd Tanks and Fuel Scoops. p. 32
B. Consider Fuel Purification Plant (block 29c).p. 32"

You determine fuel requirement, then you decide if you are putting it in drop tanks. The drop tanks are not an addition to the hull, they are taken out of available hull volume.

see above

Nor can you build an xboat without a certain interpretation of the rules, or the Annic Nova at all. With the exception of the particle barbettes which appear to be MWM's interpretation of a 10t bay (where did they go...) everything in the Gazelle is legitimate to the USP given in JTAS and built using HG'79

It is HG79 with MWM inventing the two 5t barbettes in lieu of the 10 ton bay mount

Having drop tanks is an option, you can just have regular fuel tanks. You don't need a purification plant, it is an option, your point here is lost on me.
Imafine a time before HG'80 when all you have in LBB:3 77 and HG'79 - everything has to be accounted for in hull tonnage. Bolt on drop tanks are part of the HG'80 paradigm that has become dogma.

Only when using subsequent rules, as I said in the last bit. Not many people built HG'79, ships, the revisions in HG80 and then 81 LBB: are what most people remember. The Gazelle was built using rules that pre-date those paradim changes - with MWMs usual artistic licence.

Exactly, you allocate hull tonnage when building ships, drop tanks are just another item to be accounted for from hull tonnage. At step 4 you have the option of fuel being in normal tanks or drop tanks, either way it is using hull tonnage.

Crack open HG79, you can get close...

Me neither, it is just the consensus of many people having had this discussion for over forty years.

Travelle rhas never done that sadly, and Mongoose keeps the tradition alive. The original OTU did not use all the rules in 77 edition, and features of the OTU would change as the rules themselves changed. Look at the early Library Data for Capital as an example, or the Battle of the two Suns...

Me too, I like to redesign canon ships to see how close I can get.

I completely agree. FF&S fixed it by removing the silly hardpoint restriction and instead using surface area. The same can be done in GT:ISW since hardpoints are linked to surface area.

The idea of drop tanks has changed from the initial edition to the 2nd and subsequent editions. Like many changes I think they implemented it as "cool idea" and then realized that there were massive holes in said "cool idea" that needed to be patched. Drop tanks had no explanations to them and the rules definitely made them to be optional. Which, I think, mirrors the basic idea of drop tanks anyways. Though for starships and the jump principle I've never particularly liked them. For small craft, like say a fighter, operationally they work just fine. For starships... not so much. That could just be me expecting a starship to be treated like a regular ship... and regular ships don't pull barges or have fuel bladders on their decks for range extension - they go to a port to refuel, or refuel underway. You DID see things as small as PT boats that would sometimes carry fuel drums on their decks for extended range, but they are more along the lines of a fighter than a ship.

I may sit down and see just how close I can build a Gazelle using the 77 books. As a general rule of thumb I try not to reference different book versions (even inadvertently) because it seems wrong. IF the current books don't even talk about some things, then I find looking at a previous edition to be OK - source materials should be used wherever they exist. But when the future editions change the rules, you have to pick one version and stick with it or else you get the mish-mash crap that we see far too often.

Thank you for not devolving this to a neener-neener sort of thing. Ugh.

 

[phavoc]

Two months into the war and the Outworld Coalition have accumulated 211.5 victory points. Still well short of an automatic victory and Imperial reinforcements from elsewhere in the Sector have started to arrive.
Those reinforcements have already made their presence felt, defeating the combined Sword Worlds fleets at Tavonni on the doorstep of the subsector capital Lanth.
Jewell still holds out, but only just. Emerald and Ruby have fallen.
An Imperial counteroffensive is underway against the Vargr. Pixie has been retaken, and Boughene is under Imperial siege.
View attachment 6682

It makes you wonder if the Imperium put the Marches depot too far to the rear to protect against surprise attacks. The Sword Worlds have got to know that once the dust settles, unless the Imperium is unwilling to swat them, they simply could not hold on to any of their gains. However common sense is something they seem to lack.

Has anyone designed up C3 ships like the USN built in the 50s and 60s for mobile HQ? If you think about it, having a naval HQ that is planetary (or orbital) based is both tied down and somewhat vulnerable to a sneak attack - though it's hard to be fully sneaky with a fleet that has to arrive 100D from a world. Basing your military installations at a system gas giant might actually be a better idea. Jupiter's 100D limit is 10x that of Earth. For travel it does make things longer, but for defensive purposes it radically changes the time factor. Conversely, it also makes it that much harder to defend as the other side of a gas giant is a LOT farther off.

Keep us posted on how the game is turning out!

 

[Sigtrygg]

The idea of drop tanks has changed from the initial edition to the 2nd and subsequent editions. Like many changes I think they implemented it as "cool idea" and then realized that there were massive holes in said "cool idea" that needed to be patched.

I agree.

Drop tanks had no explanations to them and the rules definitely made them to be optional. Which, I think, mirrors the basic idea of drop tanks anyways. Though for starships and the jump principle I've never particularly liked them.

Me neither, and I like the "modern" idea of recoverable reusable drop tanks to be setting changing - they open the door to tankers rueling jump ships just before jump, or jump stations fueling jump ships via long hoses...

For small craft, like say a fighter, operationally they work just fine. For starships... not so much. That could just be me expecting a starship to be treated like a regular ship... and regular ships don't pull barges or have fuel bladders on their decks for range extension - they go to a port to refuel, or refuel underway. You DID see things as small as PT boats that would sometimes carry fuel drums on their decks for extended range, but they are more along the lines of a fighter than a ship.

Once again I agree.

I may sit down and see just how close I can build a Gazelle using the 77 books. As a general rule of thumb I try not to reference different book versions (even inadvertently) because it seems wrong. IF the current books don't even talk about some things, then I find looking at a previous edition to be OK - source materials should be used wherever they exist. But when the future editions change the rules, you have to pick one version and stick with it or else you get the mish-mash crap that we see far too often.

It's one of the reasons I don't see the point to the grandfathered Imperial ships in Mongoose High Guard, the rules now allow for much better ships to be built (in truth better ships than those in CT S:9 can be designed with HG80).

Thank you for not devolving this to a neener-neener sort of thing. Ugh.

Thank you for the good natured discussion.

 

[MasterGwydion]

Perhaps. It should be abundantly clear that starships (even 6g ones) cannot travel at ridiculously high mach numbers except at the upper limits of the atmosphere where there is very little resistance.

Which is why I keep saying that. People keep bringing up atmosphere saying it's impossible to fly to the other side of the world in 45 minutes. I said that it is easy, just go up out of the atmosphere, over to your destination, and then back down into the atmosphere.

The charts, as written, are highly misleading. This has always been a complaint I've had with rulebooks that leave it vague and ill or undefined. The reality should be much more nuanced - that starships travel at subsonic speeds when entering or leaving the stratosphere and below. This still works for planets with denser atmospheres. And for simplicity sakes you can use the MT forumula by adding / reducing overall speed by 25% once you start going into thin/dense atmospheres.

Here is the space shuttle data.
The impressive speed of the space shuttle during launch reflects the various stages it must progress through to achieve orbit, which involves an intricate balance of engineering and physics.

1. Liftoff Phase:
   The liftoff phase begins at 0 km/h and rapidly accelerates. The shuttle climbs vertically with the help of its engines and solid rocket boosters, reaching approximately 100 km/h just a few seconds after launch.
2. Maximum Dynamic Pressure (Max Q) Phase:
   The maximum dynamic pressure, or Max Q, occurs when the shuttle’s speed and air density create the greatest stress on the vehicle. By this stage, the shuttle reaches speeds of about 800 km/h. This moment is critical as engineers must ensure the shuttle withstands both aerodynamic forces and structural integrity.
3. SRB Separation:
   Approximately two minutes into the flight, the solid rocket boosters (SRBs) are jettisoned after achieving speeds around 4,800 km/h. This separation reduces the spacecraft’s total weight and allows the orbiter to continue ascending into space with its main engines.
4. Orbital Insertion:
   Upon reaching low Earth orbit, the shuttle must achieve speeds near 28,000 km/h. This speed is necessary to maintain a stable orbit, counteracting Earth’s gravitational pull. The orbital insertion involves precise calculations to ensure the shuttle enters the right trajectory to reach its destination.

All of that seems a lot faster than subsonic.

There are also limitations to the high-speeds, such as very large turning radius that any craft has to deal with, so point to point will often be very predictable straight lines (in as much as you can do when travelling around the globe).

Take the same path as a ballistic missile. Easy. You don't need to turn anymore than a plane needs to turn between NY and LA and the shuttle has anti-grav, since you are out of the atmosphere.

Depending on how you play and to what level of detail this may not be an issue for many. Others may be looking for such definitions as it's going to be part of their game. It's always nice to have such things pre-defined or worked out ahead of time.

I would love a chart that correctly stated what the max speed in an atmosphere of a Standard Hull, Streamlined Hull, and if having Aerofins increases that speed at all.

 

[phavoc]

I agree.

Me neither, and I like the "modern" idea of recoverable reusable drop tanks to be setting changing - they open the door to tankers rueling jump ships just before jump, or jump stations fueling jump ships via long hoses...

Once again I agree.

It's one of the reasons I don't see the point to the grandfathered Imperial ships in Mongoose High Guard, the rules now allow for much better ships to be built (in truth better ships than those in CT S:9 can be designed with HG80).

Thank you for the good natured discussion.

I remember a lot of head scratching picking up MT - Fighting Ships of the Shattered Imperium. I have never understood the book designs not taking into account any of the optional rules. Or ships not even mounting reasonable defenses against the proliferation of radiation-based weapons.

 

[phavoc]

Which is why I keep saying that. People keep bringing up atmosphere saying it's impossible to fly to the other side of the world in 45 minutes. I said that it is easy, just go up out of the atmosphere, over to your destination, and then back down into the atmosphere.

MT provided for NOE and other speeds for starships - not that you'd expect to see a lot of starships flying NOE, but the speeds were VERY reasonable - even for the smaller vessels. The key is always making sure the charts explain stuff so people don't have to infer or guess (which often aren't what the designers meant).

Here is the space shuttle data.
The impressive speed of the space shuttle during launch reflects the various stages it must progress through to achieve orbit, which involves an intricate balance of engineering and physics.

1. Liftoff Phase:
   The liftoff phase begins at 0 km/h and rapidly accelerates. The shuttle climbs vertically with the help of its engines and solid rocket boosters, reaching approximately 100 km/h just a few seconds after launch.
2. Maximum Dynamic Pressure (Max Q) Phase:
   The maximum dynamic pressure, or Max Q, occurs when the shuttle’s speed and air density create the greatest stress on the vehicle. By this stage, the shuttle reaches speeds of about 800 km/h. This moment is critical as engineers must ensure the shuttle withstands both aerodynamic forces and structural integrity.
3. SRB Separation:
   Approximately two minutes into the flight, the solid rocket boosters (SRBs) are jettisoned after achieving speeds around 4,800 km/h. This separation reduces the spacecraft’s total weight and allows the orbiter to continue ascending into space with its main engines.
4. Orbital Insertion:
   Upon reaching low Earth orbit, the shuttle must achieve speeds near 28,000 km/h. This speed is necessary to maintain a stable orbit, counteracting Earth’s gravitational pull. The orbital insertion involves precise calculations to ensure the shuttle enters the right trajectory to reach its destination.

All of that seems a lot faster than subsonic.

Keep in mind the shuttle isn't flying vertically. Like all rockets it starts off vertical, but then takes on a tilt so that it's flying at an angle. This is because they need horizontal speed to reach orbit. A grav-equipped vehicle does not - however a ship that needs to travel to the other side of the planet will take on a trajectory similar to that of the shuttle.

And yes, it's faster than subsonic because it can't cheat physics with anti-grav. With anti-grav you can literally go straight up (and onboard gravity makes the trip much more pleasant for crew and passengers).

Just like a grav-equipped starship can float down for landing and avoid the messy reentry that the shuttle has to do (first fire its OMS to slow down enough so that it sinks back down, then spin around and take all the heat and friction that a deorbit generates. Then it has to do some maneuvering to decelerate.

As a funny aside, when I was younger i lived in Clear Lake (a suburb of Houston) which was next to NASA Johnson Space Center. I mowed the yard of one of the developers for the space shuttle flight simulator. One day he took me to go see the shuttle simulator there and we had to dodge the Marine guard at the front door (we went in the side, security was much easier back in the day). When I was on the simulator flight deck he told me a story of when some other developers thought "what if the Soviet Union tried to shoot down the shuttle over the pacific when it was doing it slow-down maneuvers?". So they modeled it and put it on the simulator. Answer was no bueno for the Russians. No missile or aircraft at the time had any sort of chance (they didn't model nukes). It was flying too high at Mach 25 and didn't start slowing down until it was much closer to the US. But some Congressman happened to be there and blew a gasket about people playing "video games" and they weren't allowed to do such simulations any more. Boy howdy was that a lot more sophisticated than the older flight sim they had, where it was the little models on a big map that was "flown" over by a camera and you flew based on the screen in another room. Shuttle simulator was elevated and could turn and do all kinds of neat stuff. He showed me some of the other simulators at the other building, where like the F-16 used airbags on the sides of the seat to simulate G-force pressure.

Take the same path as a ballistic missile. Easy. You don't need to turn anymore than a plane needs to turn between NY and LA and the shuttle has anti-grav, since you are out of the atmosphere.

I would love a chart that correctly stated what the max speed in an atmosphere of a Standard Hull, Streamlined Hull, and if having Aerofins increases that speed at all.

Well.... one would think that. But in reality you may have crowed skies. Missiles don't have traffic jams or inbound/outbound traffic. I would imagine a busy planet would have very regulated skies and traffic patterns and ships would not be able to normally take the most efficient path due to many variables - much like air and sea traffic have to do with today. Safety trumps speed and convenience. So the ability and practicality would be two separate things. One also has to take into account noise issues related to craft breaking the sound barrier. Starships would not be built to minimize sonic booms, and people and structures on the ground have to deal with such things. Currently the air force is working on updating Vandenburg flight range, and one of the things they have to consider that Canaveral does not is that they are located next to a mountain range and are in kind of a bowl. Flight patterns that are polar-oriented produce sound along the seaboard and the mountains echo the sound back, too. So noise abatement is a thing that Canaveral gets to use the ocean for (their flights travel east). This is a real-world issue that gamers don't much think (or care) about. But it's all part of building an accurate world model that can be used, or discarded.

I would expect standard hulls being limited to a few hundred kph. Streamlined double or more, but not zipping around at more than Mach 1 or so - mostly because you would not be wasting the credits to design a ship to be uber fast in an atmosphere if it's planned ops location is a vacuum. Aerofins should not impact speed at all, just maneuverability. With slower speed and anti-grav a starship could just let the air act as a brake and reverse course. Not necessarily as well as a purpose-built atmo craft, but even bricks could dance a (slow) jig if they can ignore lift and weight (though not mass).

 

[MasterGwydion]

MT provided for NOE and other speeds for starships - not that you'd expect to see a lot of starships flying NOE, but the speeds were VERY reasonable - even for the smaller vessels. The key is always making sure the charts explain stuff so people don't have to infer or guess (which often aren't what the designers meant).

Keep in mind the shuttle isn't flying vertically. Like all rockets it starts off vertical, but then takes on a tilt so that it's flying at an angle. This is because they need horizontal speed to reach orbit. A grav-equipped vehicle does not - however a ship that needs to travel to the other side of the planet will take on a trajectory similar to that of the shuttle.

This matters why? I was showing you the speed it achieves as well as when it achieves those speeds. How many Gs was liftoff for the space shuttle? Something like 3 Gs? Same as the Shuttle in High Guard, so they can go just as fast. The shuttle isn't exactly aerodynamic. It has been described as a "flying brick", but I would bet that it would count as Streamlined in the ship construction rules. So, a 3 G shuttle from Traveller, should be just fine at whatever speeds that the space shuttle from 1980s Earth could do.

Well.... one would think that. But in reality you may have crowed skies. Missiles don't have traffic jams or inbound/outbound traffic. I would imagine a busy planet would have very regulated skies and traffic patterns and ships would not be able to normally take the most efficient path due to many variables - much like air and sea traffic have to do with today. Safety trumps speed and convenience. So the ability and practicality would be two separate things. One also has to take into account noise issues related to craft breaking the sound barrier. Starships would not be built to minimize sonic booms, and people and structures on the ground have to deal with such things. Currently the air force is working on updating Vandenburg flight range, and one of the things they have to consider that Canaveral does not is that they are located next to a mountain range and are in kind of a bowl. Flight patterns that are polar-oriented produce sound along the seaboard and the mountains echo the sound back, too. So noise abatement is a thing that Canaveral gets to use the ocean for (their flights travel east). This is a real-world issue that gamers don't much think (or care) about. But it's all part of building an accurate world model that can be used, or discarded.

Isn't that what air traffic control at the starport is for? Or that Flight Control Software. I forget what it's called.

 

[Condottiere]

One advantage to gravitational based drives, is that if they stop moving in the air, it's not a given that they drop down and crash.

 

[MasterGwydion]

One advantage to gravitational based drives, is that if they stop moving in the air, it's not a given that they drop down and crash.

Yeah, but with M-Drives you stop kind of like a train. It takes a long distance.

 

[Condottiere]

They can flip over.

Plus, air resistance.

 

[ProfGrizzlyJon]

Which is why I keep saying that. People keep bringing up atmosphere saying it's impossible to fly to the other side of the world in 45 minutes. I said that it is easy, just go up out of the atmosphere, over to your destination, and then back down into the atmosphere.

Here is the space shuttle data.
The impressive speed of the space shuttle during launch reflects the various stages it must progress through to achieve orbit, which involves an intricate balance of engineering and physics.

1. Liftoff Phase:
   The liftoff phase begins at 0 km/h and rapidly accelerates. The shuttle climbs vertically with the help of its engines and solid rocket boosters, reaching approximately 100 km/h just a few seconds after launch.
2. Maximum Dynamic Pressure (Max Q) Phase:
   The maximum dynamic pressure, or Max Q, occurs when the shuttle’s speed and air density create the greatest stress on the vehicle. By this stage, the shuttle reaches speeds of about 800 km/h. This moment is critical as engineers must ensure the shuttle withstands both aerodynamic forces and structural integrity.
3. SRB Separation:
   Approximately two minutes into the flight, the solid rocket boosters (SRBs) are jettisoned after achieving speeds around 4,800 km/h. This separation reduces the spacecraft’s total weight and allows the orbiter to continue ascending into space with its main engines.
4. Orbital Insertion:
   Upon reaching low Earth orbit, the shuttle must achieve speeds near 28,000 km/h. This speed is necessary to maintain a stable orbit, counteracting Earth’s gravitational pull. The orbital insertion involves precise calculations to ensure the shuttle enters the right trajectory to reach its destination.

All of that seems a lot faster than subsonic.


Take the same path as a ballistic missile. Easy. You don't need to turn anymore than a plane needs to turn between NY and LA and the shuttle has anti-grav, since you are out of the atmosphere.

I would love a chart that correctly stated what the max speed in an atmosphere of a Standard Hull, Streamlined Hull, and if having Aerofins increases that speed at all.

• Fast (300–500 km/h) — Standard Hull
• Subsonic (800–1,200 km/h) — Streamlined Hull
• Supersonic (1,200–6,000 km/h) — Streamlined + Aerofins

You could also go with: To use Speed Band 10 (Hypersonic) in atmosphere without extra checks, a ship must be Streamlined and have at least 2G M-drive. Otherwise, each combat round at Hypersonic requires a Difficult (10+) Pilot check or the ship takes 1D hull damage from aerodynamic and thermal stress.

 

[phavoc]

This matters why? I was showing you the speed it achieves as well as when it achieves those speeds. How many Gs was liftoff for the space shuttle? Something like 3 Gs? Same as the Shuttle in High Guard, so they can go just as fast. The shuttle isn't exactly aerodynamic. It has been described as a "flying brick", but I would bet that it would count as Streamlined in the ship construction rules. So, a 3 G shuttle from Traveller, should be just fine at whatever speeds that the space shuttle from 1980s Earth could do.

Cause that's how rockets differ from grav-equipped starships. If a rocket doesn't achieve about 17k mph in orbital velocity gravity pulls it down. Perfect example - Bezos rocket goes straight up, and gravity pulls it back down. It achieves an ascent into space, but does not achieve orbit. Watch this video and it explains why -

Isn't that what air traffic control at the starport is for? Or that Flight Control Software. I forget what it's called.

Yes. That's why it's possible you cannot do what you propose all the time.

 

[phavoc]

They can flip over.

Plus, air resistance.

Grav-based drives still have inertia. In an atmosphere you can use drag to slow down. You would also be able to use your anti-grav to play with lift to change your attitude in ways a descending rocket craft could not.

Still gotta slow down one way or another.

 

[ProfGrizzlyJon]

• Fast (300–500 km/h) — Standard Hull
• Subsonic (800–1,200 km/h) — Streamlined Hull
• Supersonic (1,200–6,000 km/h) — Streamlined + Aerofins

You could also go with: To use Speed Band 10 (Hypersonic) in atmosphere without extra checks, a ship must be Streamlined and have at least 2G M-drive. Otherwise, each combat round at Hypersonic requires a Difficult (10+) Pilot check or the ship takes 1D hull damage from aerodynamic and thermal stress.

@MasterGwydion glad you approve. I have ported some of the 2300AD rules IMTU, and this played a huge role in some atmospheric/aquatic adventures we encountered. BLUF: Air is also a fluid, and aquatic spaceships have similar problems (especially without super-cavitation grav drives).

 

[MarcusIII]

Supersonic (1,200–6,000 km/h) — Streamlined + Aerofins

Adding fins shouldn't increase speed. In fact ADDING fins would slow the craft via induced drag.

 

[Fluffy Bunny Feet]

Adding fins shouldn't increase speed. In fact ADDING fins would slow the craft via induced drag.

I don't believe that he means the fins increase speed but they allow control at higher velocities.

 

[MasterGwydion]

Cause that's how rockets differ from grav-equipped starships. If a rocket doesn't achieve about 17k mph in orbital velocity gravity pulls it down. Perfect example - Bezos rocket goes straight up, and gravity pulls it back down. It achieves an ascent into space, but does not achieve orbit. Watch this video and it explains why -

Yes. That's why it's possible you cannot do what you propose all the time.

I was using this to illustrate how fast things can go, not how they differ from grav-equiped starships.

 

[ProfGrizzlyJon]

I don't believe that he means the fins increase speed but they allow control at higher velocities.

That is it exactly. Aerofins don’t make the hull more aerodynamic; they provide active control authority that prevents structural flutter and thermal overstress at high atmospheric speeds. The ships are still using gravity-based thrust, so these surfaces would interact there as well. Each combat round at Supersonic requires a Difficult (10+) Pilot check from aerodynamic and thermal stress, and any negative Effect is applied to any further checks until the ship slows down or leaves the atmosphere.

(these are how I handle it)

 

[ProfGrizzlyJon]

I should mention, IMTU there are four different styles of streamlining (yes, adapted from 2300AD):

• Ballistic
• Hydrodynamic
• Lifting Body
• Airframe

 

[Condottiere]

Going by Traveller travel mechanics, you could have a slow ascent rocket, since the formula is acceleration minus local gravity field, then excess acceleration divided by twice local gravity field to arrive at number of six minute rounds to reach orbit.

Terran norm at three gees means you're in orbit in six minutes.

Half that, at one and a half gees, twenty four minutes.

Assuming two and a half percent fuel consumption, per hour, that's half a percent.

I guess our reactionary rockets are really super efficient, relatively.