Building a "strategic bomber" unit

[DevianID]

Another reason for small craft to move faster then 3/5 is for use in other planets.  Gravity stronger then earths would require more thrust, so a 3/5 might not have the oomph to service all planets.  Also, 4/6 allows you to spend 4 thrust without using overthrust.  Overthrust can cause issues and excess fuel consumption, so a 4/6 craft expected to spend a lot of time going up and down, which Id imagine is most shuttles, will see some minor gains with a 4/6 engine that doesnt need to use overthrust and can just 'cruise' out to space.

[Daryk]

SI is more easily adjusted for Small Craft than ASF.

[Lagrange]

So if I've got it right, it costs 2 thrust to increase 1 velocity which drops at the end of the turn so you'll always spend at least 2 thrust to keep in the air.

It's 2 thrust for 1 velocity on the high altitude map, then -1 to velocity at the end of the turn.  To change altitude, you just change direction.  You 2 thrust minimum to stay in the air, and 1 thrust to change direction, so a minimum of 3.

On the low altitude map velocity increases are 1-for-1 with a max of 2x SI with velocity halved (round down) at the end of the turn.  To change altitude, you spend 2 thrust points.  You need 1 thrust minimum to stay in the air, and 2 thrust to add to altitude, so a minimum of 3 is reasonable.

AS rules still give me a headache.    There's got to be an easier way to word things.

Well, let's count the rule sets: :-)

• TW Space (+/- gravity)
• SO Vector Space
• High Altitude
• Low Altitude
• High-Low transition
• Low-High transition
• High-Space transition
• Space-High transition

[Zematus737]

You forgot Hyperspace!

[Luciora]

And Quasispace!

You forgot Hyperspace!

[RifleMech]

It's 2 thrust for 1 velocity on the high altitude map, then -1 to velocity at the end of the turn.  To change altitude, you just change direction.  You 2 thrust minimum to stay in the air, and 1 thrust to change direction, so a minimum of 3.

On the low altitude map velocity increases are 1-for-1 with a max of 2x SI with velocity halved (round down) at the end of the turn.  To change altitude, you spend 2 thrust points.  You need 1 thrust minimum to stay in the air, and 2 thrust to add to altitude, so a minimum of 3 is reasonable.Well, let's count the rule sets: :-)

• TW Space (+/- gravity)
• SO Vector Space
• High Altitude
• Low Altitude
• High-Low transition
• Low-High transition
• High-Space transition
• Space-High transition

Thank you. So a 2/3 unit can get up to the space interface just not beyond.
Like I said, it gives me a headache. I hope when the next edition comes out the word things a lot easier.

[Wolf72]

IF using optional "sprint" rules, a 2/3 could do 4mp to push itself out, at a cost of more fuel? Just trying to clarify.  Apologies if answered fully already -- still in summer brain mode, teacher mode engages next week ... which means I'll be less likely to read everything fully.

(also, basically any SC/DS unit doing 1/2 or 2/3 is either atmo bound or open space bound, right? -- guess it could enter atmo and then be an atmo bound transport)

[Lagrange]

IF using optional "sprint" rules, a 2/3 could do 4mp to push itself out, at a cost of more fuel?

I believe Sprint is for mechs only.

(also, basically any SC/DS unit doing 1/2 or 2/3 is either atmo bound or open space bound, right? -- guess it could enter atmo and then be an atmo bound transport)

Yes.  Further, I'd say that 1/2 is not viable in atmosphere for any extended duration because it can't climb in altitude.

1/2 is the usable space minimum.  It's actually fairly sensible for a bus type of transport.
2/3 is the usable atmo minimum. It's ok, but notably slower.
3/5 is the space/atmo minimum.  You see many dropships (particularly civilian) with this speed.

[Wolf72]

Why wouldn't 1/2 be usable in atmosphere? Other than bad/inefficient design?

[Daryk]

If you can't climb, how can you take off?

[Wolf72]

If you can't climb, how can you take off?

does this also affect CF designs then? (really not that up on basics for AT stuff) Or are they staying at the row-8 or below (did I understand that part correctly?)

[Daryk]

CF can't exit the atmosphere, so I'm not sure how that matters to the discussion...

[Lagrange]

Why wouldn't 1/2 be usable in atmosphere? Other than bad/inefficient design?

Suppose you lift off using thrust 2.  At the end of the round your velocity falls to 1.  Next round you must use 1 thrust to get your velocity up to 2 or you'll stall at the end of the round.  That leaves 1 thrust point for other stuff.  Increasing velocity to 3 does nothing because 2 or 3 velocity is halved & rounded down to 1.  It takes 2 thrust points to increase altitude, so you can't go up.  So, you can only fly at Altitude 1.  That's extraordinarily dangerous and you are limited to avoid any hills or forest.  Overall, basically not usable.

[Wolf72]

sorry Daryk, just trying to find the min move for any aero units ... are ASF/CF different in flight rules (maintaining flight that is).

think I got it Lagrange ... don't do it, could be some boondoggle. Which is now a target or training facility 

[RifleMech]

Suppose you lift off using thrust 2.  At the end of the round your velocity falls to 1.  Next round you must use 1 thrust to get your velocity up to 2 or you'll stall at the end of the round.  That leaves 1 thrust point for other stuff.  Increasing velocity to 3 does nothing because 2 or 3 velocity is halved & rounded down to 1.  It takes 2 thrust points to increase altitude, so you can't go up.  So, you can only fly at Altitude 1.  That's extraordinarily dangerous and you are limited to avoid any hills or forest.  Overall, basically not usable.

Where's my aspirin?

With liftoff requiring 2 thrust points I wonder how WWI aircraft manage to fly. A Sopwith Camel could just manage 1 Thrust Point. It makes me miss the TRO:3025 Boomerang stats that used Cruise/Flank MP.

[Daryk]

Support Vehicles are a whole other kettle of fish...

[EPG]

Where's my aspirin?

With liftoff requiring 2 thrust points I wonder how WWI aircraft manage to fly. A Sopwith Camel could just manage 1 Thrust Point. It makes me miss the TRO:3025 Boomerang stats that used Cruise/Flank MP.

To be fair, World War I aircraft WERE right on the edge of ‘barely able to fly’ a lot of them DID randomly crash into trees and hills, so the Battletech conceit that they can barely make it into the air is accurate. 

Considering how important they were to the war, it’s important to remember that aircraft had only been invented 8 years before the war began. 

[Vehrec]

In Battletech, to be fair, it's likely closer to spending 96% of the time they're operating at roughly 60% of max rated power.

Y'know, the difference between 'Cruise' and 'Overthrust'.

Thing is, you're still having to shove mass through the nozzle to move, so overthrust might not be a fantastic idea Every time you have to make suborbital or orbital.

Uh, no, with fusion engines, it's *mass flow* that determines the difference between cruise and overthrust?  You use the same engine power in both modes, but you open the fuel valves wider to get more reaction mass and more thrust.  It's a classic problem for all nuclear space engines, you get great SI in low thrust mode but if you want to accelerate faster, you need to pour more and more fuel over your heating element, or inject mass into the engine bell or do something to tilt Newton's third Law in your direction.

You don't scale your multi-terrawatt fusion reaction down and up by 40% of it's rated power to switch between cruise and overthrust, indeed, that's the opposite of what you would want to do.  Not only is that hard on the reactor, you're robbing your precious helium and hydrogen exhaust of the speed it needs in order to make you go vroom, and since the speed of those little particles is squared in terms of the energy they impart on you, you want them to go as fast as reasonably possible. One interesting side effect of this for games more simulationist than Battletech is that as you lower your acceleration, you generate more heat, since there's fewer atoms carrying heat away from the reactor in the exhaust stream and more being deposited in the reactor itself.

[RifleMech]

Support Vehicles are a whole other kettle of fish...

They still use Thrust and Velocity though.    There's just speed and altitude limits for props and airships. And at 1/2 Thrust or less, it might be easier to treat them as vehicles and not "aerospace' units like VTOLs. It required some house rules but it did work for the old Boomerang.

To be fair, World War I aircraft WERE right on the edge of ‘barely able to fly’ a lot of them DID randomly crash into trees and hills, so the Battletech conceit that they can barely make it into the air is accurate. 

Considering how important they were to the war, it’s important to remember that aircraft had only been invented 8 years before the war began. 

True but they flew well enough that thousands were built.

With 2 Thrust required for take off can a plane even be built with a max of 1 Thrust? I know there's a Minimum Movement rule but doesn't that apply to ground units only?

[DevianID]

I think technically all the old stuff would need to be built with the 'airship' rules that have fractional thrust.  I dont believe anything else can use fractional thrust besides an airship right?  But I think thats fair... 2 thrust is a LOT of thrust by modern aircraft standards, and so the engines and flight mechanics of btech represent a different kind of monstrously fast flying unit.  So if treating the older planes, things that cant exceed 3 velocity, as airships then you only need .5 thrust to take off; you spend fractional thrust over 4 turns, so at the end of turn 4 with .5 thrust/turn for taking off you achieve the 2 thrust needed for liftoff.

Like, when btech says 'prop plane' with a speed of 4/6, that is insanely fast.  Thats not a Sopwith camel of ww1, that is a futuristic monster that breaks the sound barrier with ease, and can fly vertical straight up.  4/6 speed units are 'super cruise' units, meaning they can hit velocity 7, the sound barrier on the .5km hex low altitude map, using just their cruising speed of 4 as I understand it.  Not only that, they can cruise up to the sound barrier right after takeoff in 3 turns/30 seconds of acceleration.  So 2/3 speed craft are still plenty fast per the real world, like many jets are less then 2/3 speed, and a 1/2 speed fighter works just fine if you dont mind needing 'afterburners' to take off and climb every other turn.

[AlphaMirage]

Max Velocity in low altitude is 2 and your speed is halved every turn. Conventional units without props can only reach Velocity 3 on High Altitude 1 which is their operational ceiling. Also 2 Thrust is needed per altitude and velocity.

[DevianID]

Max Velocity in low altitude is 2

Max velocity on the 'ground row' of the high altitude map is 2.  On the low altitude map, max velocity is 2x safe thrust before control rolls.

On the high altitude map, hexes are 18k across right?  If so, velocity 2 on the ground row is almost mach 2.

[RifleMech]

I think technically all the old stuff would need to be built with the 'airship' rules that have fractional thrust.  I dont believe anything else can use fractional thrust besides an airship right?  But I think thats fair... 2 thrust is a LOT of thrust by modern aircraft standards, and so the engines and flight mechanics of btech represent a different kind of monstrously fast flying unit.  So if treating the older planes, things that cant exceed 3 velocity, as airships then you only need .5 thrust to take off; you spend fractional thrust over 4 turns, so at the end of turn 4 with .5 thrust/turn for taking off you achieve the 2 thrust needed for liftoff.

Like, when btech says 'prop plane' with a speed of 4/6, that is insanely fast.  Thats not a Sopwith camel of ww1, that is a futuristic monster that breaks the sound barrier with ease, and can fly vertical straight up.  4/6 speed units are 'super cruise' units, meaning they can hit velocity 7, the sound barrier on the .5km hex low altitude map, using just their cruising speed of 4 as I understand it.  Not only that, they can cruise up to the sound barrier right after takeoff in 3 turns/30 seconds of acceleration.  So 2/3 speed craft are still plenty fast per the real world, like many jets are less then 2/3 speed, and a 1/2 speed fighter works just fine if you dont mind needing 'afterburners' to take off and climb every other turn.

I wish the XTRO:1945 rules were legal. Those rules make a distinction between pre-age of war and age of war and late aircraft and give the older planes half the movement of later ones. I still like the old Boomerang's Cruise/Flank MP though. It moved 13/20 which is slower than the Ferret VTOL's 15/23. C/F would seem to fit better for the old/slow airplanes and give them more variety than all having 1/2 thrust. But that's me.