displacement to length

[monbvol]

I do wish there were more precise measurements available because I'll admit to me 50kg/m³ suggests rather large voids where not even a stray atom can exist, large enough I don't think you could even have crew on some of the worst offenders that have lower density than this.

Of course this 50kg/m³ is based off some probably rather suspect math and an insufficient selection size of ships.  So the true density of Battletech spacecraft might be a bit better.

[I am Belch II]

Aerotech ships weight is very very light compared to other ships of size in other universes. I guess if you use general sizing for ships it helps much better. Keep the battleships over a million tons, destroyers around 500k and cruisers around 750k it works ok. Kinda like weight classes for Mechs

[Hptm. Streiger]

Lol, who else had envisioned that Naval ACs need to big "big" caliber guns... but the weight of those bullets doesn't seem to make sense... a 200kg bullet for a NavalAC10? It does 5 times the damage of the same "shot" for the AC20.

Well the clue is to have hollow projectiles, you do not consider drag as much in space as in atmosphere so a hollow large-caliber ball or "pistol" round made from light alloys with a "high density" bottom disk-shaped - should allow light "bullet" weight and large caliber.
Of course for orbital bombardment, they need to use a "fin-stabilized rod" with an ablative or explosive sabot that cooks of when re-entering

Also, the Congress doesn't sport so many guns, or are those "gun battery" - do you think that a single NAC10 is a single barrel or is it a kind of turret/battery of several guns.

[Daryk]

It would make sense if there were multiple implementations of them, just like TW scale A/Cs...

[Hairbear541]

always thought of them as weapons sponsons and not true turrets . there all mounted along the nose , sides and aft , but never on the top or bottom of the hull . think age of sail , chase armaments(bow & stern) and both broadsides . and no i haven't forgotten  fl/fr or al/ar , there still there to add extra flavor .

[Hairbear541]

got another question along the same topic , are the crew allowances based on x number of tons of the vessel in question . if anyone can help i'd be forever gratefull .

[Daryk]

The base crew, yes... but the gunners are entirely dependent on the weapons load.  Officers are determined off of both...

[Hairbear541]

evening  daryk , then what are the percentages for each type of crewing group based off the vessels tonnage ? all my books to get these formula are in storage up in toledo . and to buy off amazon for replacements are just way out of my price range .

[Daryk]

StratOps, page 150:

ADVANCED AEROSPACE UNIT
MINIMUM CREW TABLE
Minimum Crew Formula
Minimum Crew Needs =
Base Crew Minimum + Minimum Gunners

Advanced Unit Type         Base Crew Minimum
JumpShip                           6 + (1 per 20,000 tons)*
WarShip/Space Stations  45 + (1 per 5,000 tons)*
*Round up

ADDITIONAL CREW
Non-Gunners                           Minimum Crew Requirement
Communications Equipment
(per ton, see p. 212, TM)                                1
Field Kitchen (per item, see p. 217, TM)       3
MASH (per theater, see p. 228, TM)              5
Mobile Field Base (per item, see p. 330, TO) 5

Gunners
Minimum Gunners Requirement
Standard Weapons 1 per 6 weapons
Capital Weapons 1 per weapon

Crew Minimum Officer Requirement*
5 or more Crew (Total Base Crew + Total Gunners) ÷ 6 (round up)
*Inclusive to the crew (thus, for every 6 crewmen assigned, 1 is an officer)

[Hairbear541]

morning  daryk , okay i can get strat ops over on scribed and maybe tac ops there also , just 1 question which manual is tm .

[Daryk]

TM is Tech Manual... I know DriveThruRPG has the pdf...

[Hairbear541]

thanks daryk for the info , i'll check them out on price .

[Daryk]

Should be around $15...

[MechWarriorFox]

Been playing around with the displacement-to-length ratio and it gets insane. For example, using the 14m^3/ton that Traveller uses, I get 4.9 million cubic meters of volume. Using a 7m^3/ton ratio gives me 2.45 million cubic meters. The latter means -assuming an octagonal prism with an octagonal pyramid front end- that I've got something roughly 491 meters long and has a base side of 30 meters.

That still gives the ship with a density of (runs the math) almost 143 kilograms per cubic meter...

[Cannonshop]

Been playing around with the displacement-to-length ratio and it gets insane. For example, using the 14m^3/ton that Traveller uses, I get 4.9 million cubic meters of volume. Using a 7m^3/ton ratio gives me 2.45 million cubic meters. The latter means -assuming an octagonal prism with an octagonal pyramid front end- that I've got something roughly 491 meters long and has a base side of 30 meters.

That still gives the ship with a density of (runs the math) almost 143 kilograms per cubic meter...

it makes sense if you consider the mass calcs to be based on a ton of hydrogen like they use in Traveller to establish volume.

[MechWarriorFox]

it makes sense if you consider the mass calcs to be based on a ton of hydrogen like they use in Traveller to establish volume.

True, but it gets stupid huge when it is all said and done. As I said, the 7m^3/ton one -the one that would be better for a 'hard scifi' setting in terms of getting the right dimensions, given that a ship that I've designed in Children of a Dead Earth that is 20kt in mass is less than 200 meters in length and less than 25 meters in hull diameter- is pretty light, although to be honest, it might have a lighter density when I think about it...

[Hptm. Streiger]

And do the slide into insanity begins...  ::)

My decent into madnes"

Hello, friends, infidels, and target practice.
Today I was finally able to blow up one of the largest mysteries in the BattleTech Universum.

THE NAVAL AUTOCANNON - while the description in the lore sounds like a Techmarines wet-dream Nova Cannon of a fairytale universe, all you've got was a crude picture.

Now consider the NAC10 cannon for a moment, you have a heavy cannon several hundreds of tons and you've got ammunition - and the ammunition is the strange part - you get 5 rounds per ton for the lightest AC.... in other words, a gun multiple times larger and heavier than an AC20 consumes less ammunition but deals 5 times as much damage. (5 rounds in Battlespace = 5minutes, 5 rounds in TT are 50 seconds) - so for a single round we talk about 200kg per shot of a NAC10. 😱

When we look at the paradigms of space combat you want your shots be fast and you want to have many shots.... well now do this withing 200kg, one way is to shoot pebbles lots of them the other, well the other way is insanity.... and I went the way of insanity.

There you have a 10 inch cannon with a length of 40m instead of a single large propellant charge you will have several ignition chambers - (YES 💩Godwins Laws V3 principle) so you have a constant pressure the whole 40m.

Because you don't have the atmosphere you don't need a ballistic cap - no the bullet is a short cylinder with an EPF warhead (Explosive formed Penetrator - that will add additional ~2000m/s in the last part of the flight) to add more speed and limited maneuverability the shell also has a rocket booster.
And because inner ballistics bigger is better - it also features a sabot - to a total caliber of 14 inch.
At 200kg I get 3 rounds with a v0 of ~5-8km/s add the rocket and the EPF you might end with a kinetic impact of 10km/s or even more. It has 4 barrels because as you can imagine heat is a problem, so in a minute 3 barrels are shooting and one is flushed with coolant.

did you read till the end?
Did you like this madness?
Yes the gun is gar from finished just a proof of co....ehm madness, no Sparta