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Author Topic: Base Camp Engineering (Or "another thread about runways . . . roll eyes _here_")  (Read 3529 times)

Daryk

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Got any handy links? (The "drool" smiley is also missing...)

kato

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Something like this. Mastertop is a BASF-branded concrete mix consisting of 60% pure iron, there's a couple other brands on the market.

SCC

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Even surgical grade stainless steel may not be completely impervious to rusting (noting that the BT universe has inhabited worlds with some interesting atmospheric conditions). May I suggest that it would be safer to assume that the ferro component(s) of ferrocrete would be customised to suit the reactivity of each type/group of planetary atmospheric conditions.
Stainless steels is supposed to be nonreactive, I suspect by the time you have stuff rusting it or the like your dealing with stuff that's as least as bad as the worst acid rain, if not much, much worse.

TriplerSDMB

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Sorry I haven't been as up to datein this thread ****** I intended.  Been on the road for work the past few weeks and am on a tablet.

Thanks for pulling up the Camp Dwyer statistics.  I probablyforgot to mention that I'd assumed 2.5 inches woukd be an asphaltic concrete layer, which makes sense for an expedient-like runway.

And thats what I'll be diving into tonight and tomorrow night--reasonable figures for an expedient runway (for Mercs running a one-or-two year campaign and then moving on) or a more established airfield (forcible entry/airfield siezure sort of idea). My engineering's a little rusty, but I think I can recommend something straightforward, even for the non-engineer players.

Just wait until I get started on mine and UXO clearing.  ;)
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RunandFindOut

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Mine clearing is easy, just gather a few thousand people you don't like and march them through the suspected minefield a few times... >:D...(sarcasm notification)
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She ignored the dragon, and Freddy Mercury who arrived to battle it with the Power of Rock.

Col Toda

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 Cold without an advance team making arrangements for your arrival using shell companies . Plant Drop Ship no further than 150 km from objective send 2 remote sensor dispensers 67 hexes  ( 2 km ) ring around the LZ . With custom VTOLs it might take less than 10 minutes. My unit has a model of Naganata that replaces the 3 Artemis IV FCS for a command console . Between that and C3 Master computer this permits that each  mech to monitor up to 8 sensors . Carry a lot of Arrow IV units and hover tanks with TAG so any attempt at the LZ would cost greatly. I tend to tweek existing stock models of mechs to design unit variants or models and design combat vehicles from scratch .  If you can use an advance team with a shell company they start s business be it a Sand & Gravel , Waste management , or parcel delivery service which is situated  within that maximum of 150 km range from the target zone . That way you have in place a motor pool with refueling tanks . If multiple companies buy adjacent properties all you have to do is knock down the fences between the parking lots to provide 
yourself with the 150 meters  of open space for aerodyne drop ships or small craft . Only the most constantly assaulted planets or paranoid insular societies look at every exoplanetary corporate investment as an invasion tool. The best advance team do not know they are an advance team . The are just very capable OCD corporate drones that go to planet to planet setting up a business using a successful plan . They don't know and have moved on by the time the place is ever used  and have no knowledge of the true purpose is . The site could be run for years or decades as a money making legitimate business before it is activated . Should the target factory , spaceport , or community gets moved or destroyed it never gets activated and stays a legitimate business.  Cold save for recon happens with objective raids , advanced team preparation is more used for true invasion or occupation.
« Last Edit: 26 August 2017, 08:03:57 by Col Toda »

TriplerSDMB

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I've been considering this in my free time for awhile. . . and came up with some "house rules," which I could use a sanity check on (sharpen your sticks, please!) 

I've been using the bridge construction times as found on Pg 55 of Campaign Operations and the Construction Factors of each rating of Bridge (as spelled out on page 115 of Tactical Operations).  I spitballed the CFs are good for 1,000 passes during normal use.  A pass is one takeoff, one landing, or one taxi--a takeoff and landing (one launch and recovery) is two passes.  Got an aircraft heavier than your runway's CF?  Each 'heavy AC pass' counts as rounding up 1.5 times the AC weight divided by the heaviest CF of that runway. 

For example:  a 55 ton conventional fighter landing on a light runway is:  rounding up (1.5 * (55/15)) = 6 passes.  And that's just for one landing

After 1,000 passes, runways and taxiways need normal maintenance:  rubber removal, joint resealing, sweeping, hairline crack filling, weed plucking, etc.  You'll need to shut down the runway for "X" amount of days and perform the maintenance below after 1,000 passes.  This is SOP in the Air Force, although the runways are built a little better, and the airfield is shut down for a few days every six months or so just to keep up with things.  Regular maintenance eliminates the need for repairs.

Repairs are necessary if you exceed the maintenance schedule, or serious damage occurs to the pavement without destroying the hex.  Damage basically turns the pavement into a rough surface by reducing the CF (conventional or STVOL can't use rough surfaces).  Damage can occur by excess passes, burning or destruction on top of that pavement surface (i.e. a crash or unit destruction), deliberately aimed weapons fire that damages the pavement by reducing the CF (but not zeroing it out), etc.  Your subgrades are still there, but your surfaces are in poor shape. 

--My table (based on TacOps pg 115, CamOps pg 55, 10% rounded up and 50% rounded up):
| Runway Type    | CF    | Construction Days/Hex    | Maintenance Days/Hex    | Repair Days/Hex   
Light(1 - 15)40.42
Medium(16 - 40)111.56
Heavy(41 - 90)1829
Hardened(91 - 150)25313
Rail(151 - 650+)  32416

T'was a first stab at airfield construction and management, and I'm open to suggestion.  I wanted to keep it within existing rules, and while liberties were taken, it got me to a good start.  I used it to establish FARPs for conventional fighters, but I haven't used it yet on what I really want to play AtB with:  forced entry for airfield seizure, and main operating base establishment.  It did give me the opportunity to try to figure something out for repairing a bombed-out airstrip though.

Thoughts?

- Trip
« Last Edit: 05 August 2018, 11:08:17 by TriplerSDMB »
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SCC

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I'm pretty sure that the number of passes you've picked is low by an order of magnitude for the real world, never mind BT.

worktroll

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And I know that jet exhaust can damage aircraft carrier decks, but not prepared runways. But I do wonder about fusion-powered exhaust from BT ASFs, let alone the requirements for landing spheroid DropShips.

And yes, when people talk about landing spheroid DropShips on any flat surface, I always picture the DropShip settling into a shallow lake of molten glass ...
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Daryk

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I always figured any planet that had the water to spare cooled the landing pad like we currently cool our launch pads (i.e., with tons and tons of water, literally).

Colt Ward

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I always figured any planet that had the water to spare cooled the landing pad like we currently cool our launch pads (i.e., with tons and tons of water, literally).

Isn't that actually in the fiction somewhere?  I want to say maybe Acamar in the 2nd MWDA book?
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kato

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The water sprays in real-life launch pads aren't used for cooling, they serve as a sound suppression system. The idea behind it is that it suppresses the acoustic pressure wave that reflects off the ground from the engine - before it hits the rocket. This was needed in particular for the Space Shuttle with its solid boosters which have a particularly large, snappy pressure wave.

Cooling was only a very secondary effect, much like e.g. pushing out any gaseous hydrogen emanating from the engine ahead of firing so it wouldn't spontaneously ignite.

In real-life launchpads, some "bleeding off" of the heat is done in the flame trench beneath, which is covered in five inches of concrete (on top of the steel deflectors) that flake off and have to be regularly replaced/repaired.
« Last Edit: 21 August 2018, 16:35:51 by kato »

worktroll

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Chemical flames - heat in terms of a couple of thousand degrees (K, C ,or F, take your pick ;) )

Output from a fusion-powered engine capable of moving 10,000 tons at 2.5G??

Okay, landings & takeoffs will be managed at a conservative 1.5G. The Saturn V weighed around 3,000 tons all up, for comparison.

I'd have to check TM or other rulebook, but at least the Overlord's engines aren't spewing direct fusion byproduct. Cray has previously fluffed it as the fusion plant provides the power, which the engines then use to heat the reaction mass - giant microwave ovens being one possibility. The heated reaction mass then exits the "engine" producing thrust.

Given the near-magical efficiency of BT engines, let's say on the order of 10,000 degrees?
* No, FASA wasn't big on errata - ColBosch
* The Housebook series is from the 80's and is the foundation of Btech, the 80's heart wrapped in heavy metal that beats to this day - Sigma
* To sum it up: FASAnomics: By Cthulhu, for Cthulhu - Moonsword
* Because Battletech is a conspiracy by Habsburg & Bourbon pretenders - MadCapellan
* The Hellbringer is cool, either way. It's not cool because it's bad, it's cool because it's bad with balls - Nightsky
* It was a glorious time for people who felt that we didn't have enough Marauder variants - HABeas2, re "Empires Aflame"

Colt Ward

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I want to say the system was designed to douse the hull to cool it from reentry as well as evaporating off the pad to help cool the area.

Should a spaceport's ferrocrete pad be one big heatsink using the same coolant as mechs?

It does make one wonder about fiction describing snow on Tharkad's spaceport pad & structures after someone landed . . .
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kato

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I'd have to check TM or other rulebook, but at least the Overlord's engines aren't spewing direct fusion byproduct. Cray has previously fluffed it as the fusion plant provides the power, which the engines then use to heat the reaction mass - giant microwave ovens being one possibility. The heated reaction mass then exits the "engine" producing thrust.
Technically you could also upscale a Hall Thruster horribly given existant energy supplies. Something on the order of 3-4 GW output should be enough to provide 1.5g to 10,000t. A bit high for a fusion reactor - in a tokamak design the plasma chamber alone would be around 2-3% of the ship's volume - but should be doable technologically.

Daryk

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I'm not so sure of that math... back in college, I calculated the maximum possible thrust using only fusion products accelerated to relativistic speeds.  It was well below that necessary to accelerate ships at the listed values.  Or were you just ignoring the reaction mass requirements for those Hall thrusters?

kato

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Or were you just ignoring the reaction mass requirements for those Hall thrusters?
For the landing we can ignore it, provided we have atmosphere...

Besides, we have paper thin armor and fusion reactors weighing as much as a car engine. We can safely ignore such measly things as reaction mass anyway ;)

SCC

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Besides, we have paper thin armor and fusion reactors weighing as much as a car engine. We can safely ignore such measly things as reaction mass anyway ;)
It's a pity the game doesn't.

TriplerSDMB

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I'm pretty sure that the number of passes you've picked is low by an order of magnitude for the real world, never mind BT.

I was keeping this at the '"expeditionary" base camp level' i.e. a FOB or an airfield for couple-years' use or less.  Real-world airfields are built to last for decades, and you're right, they take a lot more passes and beatings than an expeditionary airfield would.  I only drew up these ideas for my AtB campaign.   

And I know that jet exhaust can damage aircraft carrier decks, but not prepared runways. But I do wonder about fusion-powered exhaust from BT ASFs, let alone the requirements for landing spheroid DropShips.

Back IRL, in the Air Force, we'd never really dealt much with damage from exhaust.  Most of our repairs and remediation were from passes, or runway rubber removal (from tires).  That's not to say blast damage doesn't occur, but those jets were only passing over the concrete, and didn't have the time to really raise the temperature to anything meaningful.  Concrete sunk the heat away to the base courses anyway.  But now that I recall things, engine test pads were angled slightly (2-3% IIRC) to elevate the exhaust up and away from the surface, slightly.

And yes, when people talk about landing spheroid DropShips on any flat surface, I always picture the DropShip settling into a shallow lake of molten glass ...

I wondered what a spheroid DropShip would do to a flat, grassy plain. 

Trip
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idea weenie

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And I know that jet exhaust can damage aircraft carrier decks, but not prepared runways. But I do wonder about fusion-powered exhaust from BT ASFs, let alone the requirements for landing spheroid DropShips.

And yes, when people talk about landing spheroid DropShips on any flat surface, I always picture the DropShip settling into a shallow lake of molten glass ...

With the thrust of the engine, I'd expect any melting surface material to be blown away by the Dropship's exhaust.  So maybe a slight crater would be the result, and a lot of dust in the atmosphere afterward.

Remember, the Dropship's engine is not just a massive heat source, it is also producing enough thrust downward to calmly settle a multi-kiloton vehicle onto the planet without performing a lithobraking maneuver.

Colt Ward

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Remember, the Dropship's engine is not just a massive heat source, it is also producing enough thrust downward to calmly settle a multi-kiloton vehicle onto the planet without performing a lithobraking maneuver.

Military ships do not . . . do merchant ships?  I would imagine it saves a bit on fuel costs since its 'free' decel.
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kato

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Not exactly free when you consider the cost of armor...

Colt Ward

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Which stands up to heat from weapons- Plasma Cannons after all do not cause damage while Rifles do . . . jump jets generally do not damage armor (torso mounted jets to the rest of the back/legs), flamers cause a little damage . . . and mechs can work in lava for a bit IIRC, but do take damage.
Colt Ward

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idea weenie

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Which stands up to heat from weapons- Plasma Cannons after all do not cause damage while Rifles do . . . jump jets generally do not damage armor (torso mounted jets to the rest of the back/legs), flamers cause a little damage . . . and mechs can work in lava for a bit IIRC, but do take damage.

The basic idea is you have extremely high-speed fusion products spewing out the bottom of the ship against a surface that is starting to turn liquid.

A good way to compare this is by getting a dinner plate and pouring some water in it.  Now take a straw and blow vertically at the water at the center of the plate.  Start with the straw about a foot away from the water, and watch the water as you move the straw closer.  That is a low-velocity/energy approximation of what a Dropship's engines will do to anything loose on the landing pad (and liquid definitely counts as loose).

Colt Ward

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Not talking about that?  Discussing the hull being used for aerobreaking vs what it already does . . . besides, I think we have aerodyne using aerobreaking along with small craft and ASF so why not spheriods?
Colt Ward

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