Landing Atmo capable ships

[gchuck]

100t Scout as example, how do these things land?
I've seen art work showing, thrusters. And some that show wheels, that leads me to think they land like an airliner.
The greatest number of 'pictures' I've seen have extendable 'bricks' to rest on.
That seems the most logical.....
Ok.
If it's thrusters, where are they in the deck plans? They show the 'gear wells'.
I just assumed it was grav generators built into the hulls, allowing a vertical descent to a soft landing.
Whats the consensus?

 

[mike wightman]

Some ships have wings or lifting body designs - these could land like a plane.

The most sensible idea is that grav technology allows them to hover and then land.

 

[Timerover51]

100t Scout as example, how do these things land?
I've seen art work showing, thrusters. And some that show wheels, that leads me to think they land like an airliner.
The greatest number of 'pictures' I've seen have extendable 'bricks' to rest on.
That seems the most logical.....
Ok.
If it's thrusters, where are they in the deck plans? They show the 'gear wells'.
I just assumed it was grav generators built into the hulls, allowing a vertical descent to a soft landing.
Whats the consensus?

I assume that the ship kills forward motion with its maneuvering drive, extends landing pads if it has them, otherwise a reinforced bottom, and then settles down by slowing reducing the contra-gravitional field. My Free Traders basically have reinforced bottoms as long as the surface is reasonably level and fairly solid. A level piece of hard-packed gravel works for the smaller ships. Larger and heavier ones need a level reinforced concrete surface.

 

[AnotherDilbert]

100t Scout as example, how do these things land?

Differs by edition. MT used only thrusters, TNE (& T5?) specifically use grav. CT and MgT is fairly undefined.

Starships gently floating down on anti-gravity is assumed by many, but not specified before TNE.

 

[agorski]

T5 hulls include Lifters by default for low-speed hovering maneuvers.

 

[Ex_Pendable]

I find it curious that Traders and Gunboats only shows two landing pylon wells for the 100t Scout, there's no forward well listed on the plans. Possibly they believe the mass of the engines allows it to balance on two feet?

There's also the issue of boarding while landed, as the main hatch is three meters up, requiring some sort of passenger stairway, available only at starports. Possibly while exploring strange, new worlds without benefit of a starport they rely on a rope boarding ladder or there's some extendable ramp? Of course, you can always take the air raft.

Be it as it may, the Maneuvering Drive does not produce thrust in the conventional sense of a chemical reaction rocket. Instead, it manipulates gravitons using an array, formally known as "thruster plates". The drive can generate 100% of thrust in one direction and could conceivably be placed anywhere in the ship, but by tradition engineering is located in the aft end of the vessel where the light and heat can radiate behind the ship. However, it can create 25% lateral thrust to the sides of the ship - conventionally port (left), starboard (right), overhead (top), or below (bottom). By switching elements of the array from aft thrust to lateral thrust, the ship can hover or glide into place, then reduce power to allow it to land.

Counter or forward thrust to make the ship move backward, however, it can only manage at 10% efficiency.

In the event of maneuver drive failure, there is an auxiliary thruster system built into the hull - typically a gas jet type. Pilots lighting these off during a non-emergency landing may be accused of "showboating" or overreacting (pilot error).

 

[Condottiere]

I assume thrust is directional.

Tilt motors would seem an easy answer.

 

[Selandia]

Cancelling grav is one thing,

Ordely 0g movement in (sometine turbulent) athmos is something else. Of course the attitude thrusters, the main engines (often portrayed as double exaust ) alternating the grav plate power and ship's attitute... could all provide controlled movement. T5 do provide an athm manoeuver bonus for hull with airlifting capability (wing, wedge...)

Have fun

Selandia

 

[Drakon]

On the issue of landing pads or wheels, I go for wheels. Yes they are more bulky, expensive and more moving parts, but it allows one to tow the aircraft across the field without turning the engines on.

The Suliemanns have been around for roughly 250 years (in 1116) and built on thousands of different worlds. Throw in maintenence re-configurations, there is probably quite a variety of layouts, and specific equipment arrangements. Some may have wheels, some skids.

 

[atpollard]

Traveller ships with thick armored hulls (any standard deep space hull in Traveller) has a weight that makes wheels impractical. Take the typical Type A trader as an example. At 200 dTons, it has a mass in the ballpark of 2000 metric tons. The weight capacity of the tire on an 18 wheeled truck is about 1 metric ton per tire. The typical Type A Starship needs 2000 truck tires to support its weight.

If we reduce the Starship to the average density of the Space Shuttle, then it only weighs 800 metric tons and needs 800 truck tires.

These starships are just too blessed huge for tires.
(If you are thinking of using stronger tires, you only need 200 of those giant tires used on those huge mining dump-trucks for a Type A Starship.)

 

[infojunky]

Traveller ships with thick armored hulls (any standard deep space hull in Traveller) has a weight that makes wheels impractical. Take the typical Type A trader as an example. At 200 dTons, it has a mass in the ballpark of 2000 metric tons. The weight capacity of the tire on an 18 wheeled truck is about 1 metric ton per tire. The typical Type A Starship needs 2000 truck tires to support its weight.

Often the theoretical mass of a Traveller ships makes me ponder how much aerodynamic lift they actually could have.

Though I am a huge fan of Tailsitters and the straight drop from orbit landing style for all but the smallest of ships.

 

[Condottiere]

Donno; probably great at mach thirty six atmospheric reentry.

Pop out wings at lower altitude might be a thought.

 

[AnotherDilbert]

Often the theoretical mass of a Traveller ships makes me ponder how much aerodynamic lift they actually could have.

By CT streamlining does not imply lift, it simply means that the hull will not burn up, or have parts fall off, during powered lift-off or reentry.

Streamlining refers to the ability of the ship to enter atmosphere (partial streamlining allows fuel skimming but prohibits entry into world atmospheres for the purpose of landing).

MT introduced airframe configuration with lift, but by then the classical designs were already set.

Though I am a huge fan of Tailsitters and the straight drop from orbit landing style for all but the smallest of ships.

I agree that tail-sitters fit Traveller technology better.

"Straight drop" is difficult to realise, since planets do not conveniently sit still, but move in orbits and rotate. To drop straight down the ship would have to fall in a spiral around the planet synchronised to the planets rotation, while following the planet's orbit.

 

[Selandia]

...
These starships are just too blessed huge for tires.
(If you are thinking of using stronger tires, you only need 200 of those giant tires used on those huge mining dump-trucks for a Type A Starship.)

BTW same math applys to landing gear (wheel or pad) and landing field. Three points stand for 2,000 tons is a structural challenge for both the beast and the nest, even if grav plates make the landing a feather drop... once power is cut....

Love water landing, with pressure distributed along the hull

Have fun

Selandia

 

[whartung]

We have anti-gravity lifters. Who needs wheels?

 

[atpollard]

We have anti-gravity lifters. Who needs wheels?

I agree, just leave the engine running and hover. Then there are no issues with a landing leg with a 666 tonne point load on a ground with a 10 tonne per square meter load bearing capacity.

 

[infojunky]

By CT streamlining does not imply lift, it simply means that the hull will not burn up, or have parts fall off, during powered lift-off or reentry.

That's ok, I question streamlining fairly often as well. But that all depends on the perceived reentry profile and how well a ship handles the last 5 miles of Atmosphere.

I agree that tail-sitters fit Traveller technology better.

"Straight drop" is difficult to realise, since planets do not conveniently sit still, but move in orbits and rotate. To drop straight down the ship would have to fall in a spiral around the planet synchronised to the planets rotation, while following the planet's orbit.

Straight down all depends on the observers point of view...

 

[Drakon]

Traveller ships with thick armored hulls (any standard deep space hull in Traveller) has a weight that makes wheels impractical. Take the typical Type A trader as an example. At 200 dTons, it has a mass in the ballpark of 2000 metric tons. The weight capacity of the tire on an 18 wheeled truck is about 1 metric ton per tire. The typical Type A Starship needs 2000 truck tires to support its weight.

Okay lets go with an example just a bit different but more relevant to me. A 100 dton '96 Rhylanorian Sulieman Scout Courier, TL 15.

The Megatraveller stats I have show the 100 ton ship weighs "Unloaded = 840 tons, loaded 916 tons". So 1 ton per tire, at TL 7 (Or are we 8?) won't ever increase?

I still say having a ship where you need to keep the reactor going every second or you lose the landing gear is a problem. We can agree to disagree on this point. I am using 10 tires (2 sets of 4 plus 1 set of 2 forward), so, 100 tons per tire, roughly.

One other thing that really bugs me is the deck hatch outside the engine room. If I had a nickel for every time I fell through that damn thing...well, I could probably pay for the yard period. Moving it 1.5 meters either way is a lot less dangerous.

 

[atpollard]

The Megatraveller stats I have show the 100 ton ship weighs "Unloaded = 840 tons, loaded 916 tons". So 1 ton per tire, at TL 7 (Or are we 8?) won't ever increase?

The trick becomes getting the ground to support the weight. For example, a steel wheel on a train can hold a lot more weight, but then you need a steel rail to support it. It would cut through an asphalt or concrete road. So a super tire will either need a super-alloy runway or it will need to be wider to spread out the load.

 

[atpollard]

One other thing that really bugs me is the deck hatch outside the engine room. If I had a nickel for every time I fell through that damn thing...well, I could probably pay for the yard period. Moving it 1.5 meters either way is a lot less dangerous.

I am with you on that!