Lifters: The Other Landing Gear?

[rinku]

TNE (and MegaTraveller) were accounting for individual workstations. A lot of ship systems are just part of the hull or bridge cost in both CT and MGT.

Lifters being part of a standard hull's gravitics are good enough, just as G-compensators are part of the M-Drive.

 

[Endie]

On the basic practicality: the Martin II in the Treasure Ship adventure (PoD Episode 2) is stated as being supported by grav lifters.

It's possible, but judging from its relative scarcity in the books it's presumably not an efficient or desirable practise for some reason.

 

[Vormaerin]

In TNE though they were replacing entirely Man Drives and Thruster Plates. Frank Chadwick's mantra during development of TNE was "no more reactionless drives!" (of course, there was an outcry, and they snuck back in as an 'alternate technology' in FF&S).

They were not entirely replacing them. They have the same relationship to reaction drives as they do to reactionless drives: negating planetary gravity so you can lift off with less thrust required.

TNE (and MegaTraveller) were accounting for individual workstations. A lot of ship systems are just part of the hull or bridge cost in both CT and MGT.

Lifters being part of a standard hull's gravitics are good enough, just as G-compensators are part of the M-Drive.

yeah, that's why we are having this thread about what do they actually do and how do they work. And have a lot of similar conversations about all sorts of other "it's just part of the hull" stuff like airlocks.

 

[collins355]

They were not entirely replacing them. They have the same relationship to reaction drives as they do to reactionless drives: negating planetary gravity so you can lift off with less thrust required.

Good point - I worded my post carelessly. The "lifters" in TNE were part of an ecosystem that differed from the rest of Traveller canon in that Man drives and thruster plates no longer existed. TNE contragravity negated almost all gravity, but did not provide any thrust. You needed to fit a thrust agency (rocket, propellor, etc) in order to go anywhere.

 

[GabrielGABFonseca]

The Starship Operator’s Manual says this, so maybe that is a more direct number than .1 thrust?

I would like to point out the following passage of the SOM (Page 76):

Lifters are very useful for efficient, frictionless movement close to the ground but are not the speediest mode of transportation. Similar to helicopters, their main form of attaining translational motion is by inclining the angle at which the force keeping them airborne is applied. In low-tech lifters, this is done by physically rotating the lifter plate assembly, whereas in a more sophisticated lifter’s case it can be done by correctly timing the activation of the grav modules that make up the plate, using beamforming techniques to tilt the angle of the resulting gravity field relative to the surface. By doing this, basic lifter craft can achieve reasonable speeds on a standard atmosphere world. Going faster requires adding further propulsion systems, which are more concerned with forward velocity than keeping the vehicle off the ground. Most lifters, especially low-tech ones, operate in a low altitude regime of between half a metre off the ground for ‘ground’ vehicles and 50 metres for ‘air’ vehicles, but most lifters can in theory reach low orbital altitudes.

As for the whole "they're free" thing, yes, because SOM was written after Highguard 2022 and is technically a system-agnostic book, so it was supposed to work with both MgT2 and T5 alike. It tries to unify all of the concepts from previous Traveller editions, which maybe was a fool's errand but that was the mission statement.

For what is worth, personally I assume for Mg2T that the cost and power requirements of lifters as being inherent to any Gravity Hull (i.e.: the standard option), and that non-gravity hulls do not include lifters. I'd love to see their inclusion as actual options (along with landing gear) in a future Highguard 20XY book, though.

Personally, I don't like them. They are the thing that makes the streamlining rules for ships pretty nonsensical. If you can just lift straight up and down and don't really need to worry about aerodynamics except maybe in extreme weather, there really isn't any reason your boxy ship can't land on a planet. And with the discussions in this thread, you don't even need the different types of landing gear.

Besides that, I just think they are boring.

You're correct, but I'd like to politely point out that, with M-Drives, this was always an option too. A ship with an M-Drive can simply cancel out all of its velocity tangential to the ground while in orbit and then sedately 'fall' at a controlled rate to the ground, as long as planetary gravity is lower than its thrust rating, of course. It might have to tail-land and then "bellyflop" unto the ground (the Flea Trader on JTAS 16 does exactly this), but it's definitely possible.
The key difference is what Rinku said, because the thrust from lifters is so pathetically small, having a ship be streamlined allows you to quick the M-Drive into high gear and blast your way to orbit in an expedient manner, instead of taking the slowmobile route.

And as for your thinking they're boring – yeah, that's entirely fair actually lol
I do admit it does remove some of the excitement that comes from surface-orbit interface operations, but personally I don't mind them. Boils down to individual taste, in the end.

 

[Vormaerin]

And as for your thinking they're boring – yeah, that's entirely fair actually lol
I do admit it does remove some of the excitement that comes from surface-orbit interface operations, but personally I don't mind them. Boils down to individual taste, in the end.

Yeah, that's why I was originally staying out of this thread. It just veered off momentarily into some stuff about why it's not shown on any ships, which I felt like responding to.

When ship design was first considered and the rules on streamlined vs unstreamlined were devised back in Book 1, thrust did actually come out of the back of the ship. You could even use it as a weapon at point blank range So it made sense. But over time M-drives became increasingly magical and let you zip around in any direction with them, with various rules on how much thrust in a particular direction. So, yeah, I'm not sure the point of lifters as a separate thing from M-Drives.

T:NE didn't have M_Drives and lifters let them avoid the 2300 orbit/surface interface fun. And T5 has a variety of levels of gravitic drives for different situations.

 

[rinku]

Essentially, MGT lifters are the same technology as Air/Raft nullgrav modules. CT didn't explicitly include them as a standard part of hull or M-Drive, but it was reasonable to do so.

If we are going back to 1977 LBB, M-Drive fuel explicitly included reaction mass, although it was poorly defined and you didn't really keep track of it ("Most ships have enough for 4 weeks of operations etc"). The weaponised drive thing -for fusion rockets only - was from High Guard, not Book 2 (and certainly not Book 1...), and quietly dropped within a year of publication. I never had the first edition of HG and was unaware of that one until a few years ago. It's a historical footnote that even TNE - which had plasma drives - didn't revisit.

 

[Condottiere]

You need to know technological level, power requirement, performance, and tonnage.

 

[Vormaerin]

Essentially, MGT lifters are the same technology as Air/Raft nullgrav modules. CT didn't explicitly include them as a standard part of hull or M-Drive, but it was reasonable to do so.

If we are going back to 1977 LBB, M-Drive fuel explicitly included reaction mass, although it was poorly defined and you didn't really keep track of it ("Most ships have enough for 4 weeks of operations etc"). The weaponised drive thing -for fusion rockets only - was from High Guard, not Book 2 (and certainly not Book 1...), and quietly dropped within a year of publication. I never had the first edition of HG and was unaware of that one until a few years ago. It's a historical footnote that even TNE - which had plasma drives - didn't revisit.

I wasn't recommending it be revisited. I was pointing out that the ship hull design stuff was developed in conjunction with the idea of directional thrusters. And that GAB was correct that is has been obsolete for planetary landing purposes for far longer than introduction of lifters. Though those planetary landing rules have never been changed to reflect the changes in how starship drives work.

 

[rinku]

It might be useful to compare lifters and M-Drives to their airfoil equivalents, rotor blades and fixed wings.

Rotor blades technically only provide lift, although lateral motion can be done by tilting the craft. Helicopters are quite limited in their top speeds. even with direct lateral thrusters and good aerodynamics.

Fixed wing and direct lateral thrust aircraft are capable of much higher velocities (but can't hover).

 

[Sigtrygg]

Essentially, MGT lifters are the same technology as Air/Raft nullgrav modules. CT didn't explicitly include them as a standard part of hull or M-Drive, but it was reasonable to do so.

And yet they never have been.

If we are going back to 1977 LBB, M-Drive fuel explicitly included reaction mass, although it was poorly defined and you didn't really keep track of it ("Most ships have enough for 4 weeks of operations etc").

The maneuver drive is called a reaction drive and the amount of fuel per burn can be calculated. It comes out as 48 hours at full combat thrust. In '77 all the fuel had to be refueled per trip, the 4 weeks operation was introduced in '81.

The weaponised drive thing -for fusion rockets only - was from High Guard, not Book 2 (and certainly not Book 1...), and quietly dropped within a year of publication. I never had the first edition of HG and was unaware of that one until a few years ago. It's a historical footnote that even TNE - which had plasma drives - didn't revisit.

Even though it is not mentioned, I wouldn't want to be within a few hundred metres downwind of a HEPlaR exhaust...

 

[swordtart]

It might be useful to compare lifters and M-Drives to their airfoil equivalents, rotor blades and fixed wings.

Rotor blades technically only provide lift, although lateral motion can be done by tilting the craft. Helicopters are quite limited in their top speeds. even with direct lateral thrusters and good aerodynamics.

Fixed wing and direct lateral thrust aircraft are capable of much higher velocities (but can't hover).

Are they equivalent though? The reason for the lower speed capability of rotary craft is the issue of loss of lift in the retreating wing as speed increases. That wouldn't be the case for a non-rotary thruster and lifters are not rotary as far as I know.

Considering things from an aerofoil standpoint brings a whole load of baggage that is inapplicable to vector thrust vehicles.

You might as well say their equivalents are the vector thrusters of the Harrier VTOL aircraft as those don't rely on aerofoils for the VTOL aspect.

 

[MarcusIII]

And yet they never have been.

The maneuver drive is called a reaction drive and the amount of fuel per burn can be calculated. It comes out as 48 hours at full combat thrust. In '77 all the fuel had to be refueled per trip, the 4 weeks operation was introduced in '81.

Even though it is not mentioned, I wouldn't want to be within a few hundred metres downwind of a HEPlaR exhaust...

In my house rules all this is accounted for and simple. My players have all the rules in front of them and no guess work needed. I'll admit I was slow in doing it as I just finished those last year after tinkering for a couple years on and off