Kinunir-class landing gear

[Hyphen]

... the weight distribution would have them bobbing around tail-down...

Finally, a physics-based reason for the Scout NOT to have a flat belly: it's to compensate for being tail-heavy, so it floats "flat" with half the tail submerged... After all, who else has greater need of rough-landing capability than a Scout?

I think that "50 Starbases" may have suggested 5 or 6 thousand tons as an upper limit on hard stands. Can't remember if the more recent "Starports" says anything.

At Tavonni (Beowulf Down), I went with 0.5m of "permacrete", a kind of engineering "unobtanium" even stronger than concrete (but I used real-world concrete prices) and multiple landing pads of different sizes, up to a maximum of 6000 tons displacement. Anything larger and I assumed it would have to land in water, and I (IMTU, there's no canon) put the ceiling on that at 20,000t displacement. You're starting to get into the size of large real-world (wet) merchants and super-tankers, and they're pretty fragile for their size. I figure if you tried lifting a super-tanker on grav you'd break it's back - it needs the water all around to support & cushion it.

Never really bothered to calculate ground pressure, tho'. Just made sure we could fit that ol' triangular 1000t merchant from FASA's _Merchant Ships_.

We did attach a runway, though (one of my few disagreements with John M. Ford's magnificent tome: it should say 'ports "mostly" do not have runways, rather than they "never" do. Hard & fast rules don't work across 11,000 worlds). 'Course the main reason we use it is not for "airframe"-style starships, but just-for-fun old-fashioned aircraft we rent out to conference attendees and other tourists. Either they fly themselves or charter a plane - kinda the equivalent of going on an old stagecoach or steam train at any number of theme parks worldwide...

 

[leopard]

First post here, but this is one I thought about a while back.

Consider why a craft would land, small craft need the ability to land anywhere - and as such can, larger craft, anything in the multi KT class and higher is probably a specialist vehicle of some sort of a cargo carrier.

As such it will need a specialist landing dock to unload - regardless of the crafts mass or shape - if its carrying containers its either in need of cranes or ramps to unload at a sensible speed to get back in to flight. Bulk carriers more so will need something specialised.

Its perhaps more of a case of such craft being designed to use a range of standard landing docks which will support them properly, include shore supply connectors, refuelling rigs, crew and inspection access etc.

Military yards may well have similar for larger craft that require to go planet side, its also not too hard to picture larger warships being constructed in cradles from which they will launch directly never to land again.

Larger craft may well belly land, or more likely as I saw it, will have structural support hard points on the belly, these will "mate" to the ground pad - possibly a large crawler if you want craft landing away from the terminal (think the shuttle transport, but larger). the craft doesn't need landing gear as such, just a set of calibrated points - the transporter can then be configured before the craft lands on it.


Thats a logical discussion of course, in practice if that 20KT bulk carrier needs to be able to land an a world with a class X port and take off again, it will be able to do so, if it needs to be wreaked upon landing then likewise that will happen.

Personally I like the idea that larger craft need extensive ground facilities - unless equipped for water landing, this helps provide a role for smaller craft, let the bulk transports serve the higher population worlds - with smaller craft taking goods the "last parsec" to smaller worlds or in system.

 

[rancke]

There is no reference I've seen, per se, but there is the limit on book two hulls being 5K. ISTR a 5KTd being grounded in some adventure... but we see 2KTd and 3KTd landing planetside in The Traveller Adventure.

We see 5000T ships landing planetside too. P. 62:

"Mammoth came to Zila for a standard wine pickup only a few days after another Akerut freighter, the Titan, landed for refuelling while en route from Inthe/Regina to Aramis[*] with a military cargo." (Emphasis mine).​

Mammoth and Titan are both 5000T Hercules-class freighters.

[*] Just why a jump-1 freighter would go from Inthe to Aramis along a 10-parsec route involving three two-parsec crossings instead of an eight-parsec route involving only one two-parsec crossing is a mystery to me, as is the reason for using a jump-1 freighter in the first place, but that's a different problem.​

Hans

 

[aramis]

We see 5000T ships landing planetside too. P. 62:

"Mammoth came to Zila for a standard wine pickup only a few days after another Akerut freighter, the Titan, landed for refuelling while en route from Inthe/Regina to Aramis[*] with a military cargo." (Emphasis mine).​

Mammoth and Titan are both 5000T Hercules-class freighters.

[*] Just why a jump-1 freighter would go from Inthe to Aramis along a 10-parsec route involving three two-parsec crossings instead of an eight-parsec route involving only one two-parsec crossing is a mystery to me, as is the reason for using a jump-1 freighter in the first place, but that's a different problem.​

Hans

Thanks... This gives us that the maximum is no less than 5KTd.

 

[Carlobrand]

This discussion is bringing to mind some of the SF (esp Jerry Pournelle) in which spaceports were really seaports, and spacecraft landed on the water.

Dang, that's a good idea. If there's a crash, it happens in the water, less traumatic on the crashee and on the immediate environs - except of course for a massive amount of steam. Even if you're not doing a straight flop into water, it'd be worthwhile building landing pads out in the middle of a lake or something for that reason alone. The way folk tend to build around ports, it's likely to save a lot of lives.

 

[DaveChase]

So, how big a wave would a 5Kton ship make if it failed it's re-entry check?

That would make for an interesting adventure for the players. They are at the port which uses the ocean for a landing pad and bay. A 5Kton ship that has taken fire from pirates and has limped to the planet after the battle attempts to land on the planet.

Due to the damage it has taken, it starts tumbling and crashes (ie uncontroled landing) into the ocean.

The tidal wave strikes the port and the ships current surrounding it. They 2 hours before the wave strikes the port.

Hmm.

Dave Chase

 

[MCEvans]

Just an FYI in TD #4 talks about the 1kt Tukera Long liner. Not designed for surface landings but can with a custom grav cradle that aides in landing and take-off plus gives the ability to move the ship about the starport as needed.
It also shows how it would sit after a water landing (nose up by about 5-10 degrees).

 

[madmike]

This discussion is bringing to mind some of the SF (esp Jerry Pournelle) in which spaceports were really seaports, and spacecraft landed on the water.

David Drake uses a similar concept for both military and civilian starships in his RCN series. Starships land at a starport within a harbour and are docked at berths.

 

[Icosahedron]

I generally use 5kt as a landing limit simply because it was the limit in LBB2. It also incorporates most PC ships. However, I agree that such ships would need facilities. I don't generally envisage anything over 1kt doing wilderness landings as a matter of routine. As Leopard says, it gives the smaller craft more purpose.

 

[Carlobrand]

So, how big a wave would a 5Kton ship make if it failed it's re-entry check?

That would make for an interesting adventure for the players. They are at the port which uses the ocean for a landing pad and bay. A 5Kton ship that has taken fire from pirates and has limped to the planet after the battle attempts to land on the planet.

Due to the damage it has taken, it starts tumbling and crashes (ie uncontroled landing) into the ocean.

The tidal wave strikes the port and the ships current surrounding it. They 2 hours before the wave strikes the port.

Hmm.

Dave Chase

That would depend on a bunch of factors, like what angle relative to atmosphere it made re-entry at, what speed it was going when it hit atmosphere, how streamlined it is and whether it was running true or tumbling or bellyflopping, and suchlike. That all would ditate whether it shed enough speed while plunging from orbit to slow to terminal velocity, and what that terminal velocity actually was. After that the splash would depend on how fast it was going when it hit water, the angle it struck water at, and the ship's attitude when it struck water.

Something shaped like a scout wouldn't make much of a splash, relatively speaking - might just plunge straight down and embed itself in the lake-bottom, which would make the rescue an interesting challenge if there were any survivors. A Hercules bellyflopping at supersonic speeds would make an impressive wave, not to mention one heck of a lot of very hot steam. However, I seriously doubt the wave front would be that significant after a few minutes travel outward from the impact point. It's an expanding ring, weakening by the square of distance as it progresses outward.

 

[DaveChase]

That would depend on a bunch of factors, like what angle relative to atmosphere it made re-entry at, what speed it was going when it hit atmosphere, how streamlined it is and whether it was running true or tumbling or bellyflopping, and suchlike. That all would ditate whether it shed enough speed while plunging from orbit to slow to terminal velocity, and what that terminal velocity actually was. After that the splash would depend on how fast it was going when it hit water, the angle it struck water at, and the ship's attitude when it struck water.

Something shaped like a scout wouldn't make much of a splash, relatively speaking - might just plunge straight down and embed itself in the lake-bottom, which would make the rescue an interesting challenge if there were any survivors. A Hercules bellyflopping at supersonic speeds would make an impressive wave, not to mention one heck of a lot of very hot steam. However, I seriously doubt the wave front would be that significant after a few minutes travel outward from the impact point. It's an expanding ring, weakening by the square of distance as it progresses outward.

have fun playing with it

http://www.purdue.edu/impactearth/

Lots to read on this website

http://users.tpg.com.au/users/tps-seti/spacegd7.html

Dave Chase

 

[Carlobrand]

have fun playing with it

http://www.purdue.edu/impactearth/

Lots to read on this website

http://users.tpg.com.au/users/tps-seti/spacegd7.html

Dave Chase

Now THAT is way cool.

The Hercules isn't making much of a wave, even at high speed. At 72 KPS (steady 1 g for two hours prior to impact), 40 megaton impact, enough to pretty well obliterate the ship, but waves are less than 10 cm a kilometer off. Airblast, however, is about what you'd expect for being a kilometer off from a 40 megaton blast - a lot of falling buildings.

In my TU, ships slow to a reasonable speed before making atmosphere, so worst case scenario is a drive failure while descending followed by a crash at terminal velocity, which isn't as bad by several orders of magnitude but you still don't want to be too close to one when it hits. Other than something like that, you're primarly trying not to damage a landing leg and incur unwanted repair expense while landing.

Unfortunately, the link seems to only work once. Must be something I'm doing wrong.

 

[DaveChase]

Now THAT is way cool.

...

Unfortunately, the link seems to only work once. Must be something I'm doing wrong.

Yeah, I don't know what is wrong. I could only get on it once today too.

maybe a cookie issue.

Dave Chase

 

[Hyphen]

[*] Just why a jump-1 freighter would go from Inthe to Aramis along a 10-parsec route involving three two-parsec crossings instead of an eight-parsec route involving only one two-parsec crossing is a mystery to me, as is the reason for using a jump-1 freighter in the first place, but that's a different problem.​

Hans

They're obviously after the women and song, too...

 

[Mithras]

At TL 7 your undercarriage might look like this! 2,600 tons of crawler transporter, capable of holding a fully loaded shuttle. I suggest vertical landing, with tracks to move around the starport, spreading the impact of the weight.

 

[atpollard]

At TL 7 your undercarriage might look like this! 2,600 tons of crawler transporter, capable of holding a fully loaded shuttle. I suggest vertical landing, with tracks to move around the starport, spreading the impact of the weight.

I'd hang out at a starport just to watch that landing track retract after takeoff!
And that sucker would definitely show up on the deckplan.

[EDIT: In case I wasn't clear, I really like that concept as a mental image worth exploring.]

 

[Mithras]

Very impressive! Tracks have long been used to spread tremendous weights so its certainly an option. I think we need Gerry Anderson of Thunderbirds fame to do justice to a scale model of a Kinunir on the ground...

 

[Mithras]

Looking around:

This WW2 An-20 Havoc experimented with tracked gear:

Then of course the humungous B-36 that also experimented with a method to reduce that massive ground pressure:

With humans for scale:

The combat weight for a B-36 is only 120 metric tons, what is that in dtons (divided by 4) = 30 dtons? Or have I got it the wrong way round?!

This is a Fairchild Packet C-82:

 

[DaveChase]

Now that's cool information. I didn't know that they were considering tracks on planes that far back.

Dave Chase

 

[HG_B]

Since Streamlined ships are supposed to be able to land aircraft-style, my money would be on wheels, but is that the case ? Is that even reasonnable ?

Depends on the rule set. Streamlined ≠ to lifting body. If NOT a lifting body no real need for wheels.