Vehicle Size Design Questions

[Sturn]

Question
I have designed a few vehicles using Civilian Vehicles. I don't yet have Military Vehicles. I'm not asking for any stats at all, but for comparison can someone give me a ballpark volume for an average grav carrier/apc and grav tank size in MGT Military Vehicles?

Discussion
MGT Core spacecraft design has a list of tons dedicated as a minimum to carry small craft, vehicles, and drones (pg. 111). These are described as minimal, "form fitting" hangars or external mounts. MGT High Guard, iirc, has rules for roomier hangars. The problem I have is the tight-fitting hangar space is listed at 4 d-tons for an Air/Raft and 10 d-tons for an ATV. Flip over to Civilian Vehicles gives me a standard Air/Raft at 8 m3 and a few ATV type vehicles that range from 14m3 to 60m3. Civilian Vehicles converts these to d-tons by dividing by 10 (not 13.5 since the volume is internal space, divide by 10 for conversion to d-tons, makes sense).

So per Civilian Vehicles an Air/Raft takes up less then 1 ton, per MGT Core it takes up over 4 times that space for a "form-fitting" hangar? ATVs in Civilian Vehicles range from more then 1 ton to 6 tons. Core has them taking up 10 tons.

You could argue that even though the hangars in Core are described as "form fitting", they still take up some extra space (4x?). But, the same chart in Core lists tons for a minimal hangar for small craft that are the exact d-ton of the small craft itself. No extra space at all.

How to rectify this? I have no problem with a 1-ton air/raft needing a 4-ton garage on a starship. This could easily be explained by an air/raft not taking up the height of a standard square on a Traveller deckplan (which is 3 meters tall). The air/raft is spread out more and short. Small craft deckplans in Traveller however do seem to take up the full amount of their 3 meter tall squares, so they fit in without any wasted headspace? However, large ATVs couldn't benefit from this, in pictures they seem to be close to if not over 3 meters tall.

Thoughts? If this has been discussed before I apologize, please point me to the right thread.

 

[AndrewW]

Question
I have designed a few vehicles using Civilian Vehicles. I don't yet have Military Vehicles. I'm not asking for any stats at all, but for comparison can someone give me a ballpark volume for an average grav carrier/apc and grav tank size in MGT Military Vehicles?

29.97 M3 for the APC, 32 M3 for the G/Carrier, G/Tank 26 - 33.99 M3 (depending on TL).

Discussion
MGT Core spacecraft design has a list of tons dedicated as a minimum to carry small craft, vehicles, and drones (pg. 111). These are described as minimal, "form fitting" hangars or external mounts. MGT High Guard, iirc, has rules for roomier hangars. The problem I have is the tight-fitting hangar space is listed at 4 d-tons for an Air/Raft and 10 d-tons for an ATV. Flip over to Civilian Vehicles gives me a standard Air/Raft at 8 m3 and a few ATV type vehicles that range from 14m3 to 60m3. Civilian Vehicles converts these to d-tons by dividing by 10 (not 13.5 since the volume is internal space, divide by 10 for conversion to d-tons, makes sense).

So per Civilian Vehicles an Air/Raft takes up less then 1 ton, per MGT Core it takes up over 4 times that space for a "form-fitting" hangar? ATVs in Civilian Vehicles range from more then 1 ton to 6 tons. Core has them taking up 10 tons.

The core rulebook was done prior to the vehicle design system and you could consider the sizes in suplements 5 and 6 updates.

 

[rust]

I am afraid there is no real solution for this problem.

The core rules and High Guard use the "traditional" Traveller data of 4
dtons for an air/raft and 10 dtons for an ATV, which are not really com-
patible with the results created by the Civilian Vehicles and Military Ve-
hicles design system.

In fact, almost all the vehicle data published for Mongoose Traveller be-
fore Civilian Vehicles and Military Vehicles are almost impossible to re-
troengineer with the design system of these supplements.

In the end you can either choose one of the two data sets or rationalize
the contradictions any way you like, a logical in system explanation does
most probably not exist.

 

[Sturn]

Question
I have designed a few vehicles using Civilian Vehicles. I don't yet have Military Vehicles. I'm not asking for any stats at all, but for comparison can someone give me a ballpark volume for an average grav carrier/apc and grav tank size in MGT Military Vehicles?

29.97 M3 for the APC, 32 M3 for the G/Carrier, G/Tank 26 - 33.99 M3 (depending on TL).

Thanks, this makes me happy. I have a resin mini grav apc that by my questimates and measurements is 30-35 m3. This is in the right ballpark. I had considered sinking my resin minis in water and noting the difference to figure exact volume, but thought that might be going a bit too far.

I am afraid there is no real solution for this problem.

The core rules and High Guard use the "traditional" Traveller data of 4
dtons for an air/raft and 10 dtons for an ATV, which are not really com-
patible with the results created by the Civilian Vehicles and Military Ve-
hicles design system....

I guess this is something T5 is doing right*. Finishing the entire game system first before settling on the final core mechanics could have alleviated this. A.i. make sure vehicle and starcraft design are completely finalized before release of the Core book so there are no later contradictions.

*I'm a fan of both T5 and MGT, please don't turn another thread into a flame war.

 

[rust]

Finishing the entire game system first before settling on the final core mechanics could have alleviated this. A.i. make sure vehicle and starcraft design are completely finalized before release of the Core book so there are no later contradictions.

Yes, indeed. But, well, there are so many other problems with the design
system of Civilian Vehicles and Military Vehicles that I have meanwhile
decided to simply ignore these two supplements and return to GURPS for
all my vehicle designs.

*I'm a fan of both T5 and MGT, please don't turn another thread into a flame war.

I think I rarely started flame wars ... :lol:

 

[Sturn]

*I'm a fan of both T5 and MGT, please don't turn another thread into a flame war.

I think I rarely start flame wars ... :lol:

Not meant for you specifically! Just trying to make sure my comment didn't derail the thread. Have to walk on eggshells methinks when comparing Traveller game systems.

 

[Dave Chase]

Well, I am a fan of T5 (which ever su-do beta version it might be).

There are some things that I think T5 will make easier/better/clearer, IF it ever comes out for public.

Dave Chase

 

[Rikki Tikki Traveller]

Perhaps you can make the following compromise:

When a GROUND/AIR vehicle is installed on a starship, you have to use 4x the vehicle size for internal garage space (not exposed to vacuum, able to get aboard it while still inside the ship etc).

For Small Craft (Spaceships), you can use those fancy form-fitting thingies, but the hull of the small craft is (at least part of it is) exposed to space.

That explains why the little 1Dton air/raft needs 4Dtons of space in a ship, but a 10-ton fighter can fit in a 10-ton hangar.

If you squint a bit, it might work....???

 

[BP]

I was just looking up this thread - having checked out Civilian Vehicles and been rather saddened by the silly M3 volume as opposed to Starship designs. Really silly considering the number of .25, .5, .75 figures I saw, not to mention plenty of decimal values. (Ultimately I decided this wasn't the book for me... 'inelegant' is the term I'd use.)

The 4/10 dton things can be made to work - at least things are 'oversized' instead of the other way around. One can rationalize head room as well as swing out doors, and walking around a vehicle to get in, loadup, etc. Small craft likely have a single point of entry, complete vacumm safe enclosures, and less commonly accessible external features (like tool cabinets, suspension systems and the like).

 

[Sturn]

Perhaps you can make the following compromise:

When a GROUND/AIR vehicle is installed on a starship, you have to use 4x the vehicle size for internal garage space (not exposed to vacuum, able to get aboard it while still inside the ship etc).

For Small Craft (Spaceships), you can use those fancy form-fitting thingies, but the hull of the small craft is (at least part of it is) exposed to space.

That explains why the little 1Dton air/raft needs 4Dtons of space in a ship, but a 10-ton fighter can fit in a 10-ton hangar.

This combined with some tweaking of the hangars in MGT High Guard might work nicely. Thanks.

I was just looking up this thread - having checked out Civilian Vehicles and been rather saddened by the silly M3 volume as opposed to Starship designs. Really silly considering the number of .25, .5, .75 figures I saw, not to mention plenty of decimal values. (Ultimately I decided this wasn't the book for me... 'inelegant' is the term I'd use.)

I don't think there was anyway to get around this. Vehicles have such a large range in size. Using d-tons for vehicles means you must use decimals for the components of small vehicles. Even if you invented a smaller "mini d-ton" you are still going to end up using decimals. A system that can be used to build both a motorcycle and an aircraft carrier is just too wide-ranging to make it easy to avoid decimals. Or, you end up with some very large numbers when creating the larger vehicles. I guess its decimals (Civilian Vehicles design) vs very large numbers (High Guard capital ships). Come to think of it, even ship design uses lots of decimals when M's and K's are used to cut down on the length of numbers.

I completely understand what you are saying BP, but have designed some MGT vehicles and it was quite easy and fun. Had about the right balance of detail vs. ease of use for me (FF&S I can handle, but it doesn't mean I like using it). With my own list of errata/house rules for MGT vehicle design to correct the other problems (from discussions here), it works well for me.

 

[BP]

I completely understand what you are saying BP, ...

Actually, I was stating that I saw no reason not to use spacecraft 'tons' for vehicle volumes - especially given the fact that decimals were prevalent! (Though probably poorly from my brief look - too much 1/4 rounding.)

I do my spacecraft designs to 3 and 4 decimal places and use integrals when needed to calculate volumes I do this for consistency, creating my own tonnages when needed.

Since vehicles will often be transported on spacecraft, seems really silly not to be constistent and use common units (since decimals will be used anyway).

There were other reasons (the 'inelegance' wasn't about the math) I didn't care for the book...

 

[rinku]

The best rationalised explanation for the historic 4/10 ton figures relates to deck plans. It's two 1.5m squares per ton, meaning an Air/Raft hanger is eight squares (i.e. a 3m x 6m footprint) while an ATV hanger is 20 squares (perhaps a 6m x 7.5m footprint). That looks about right in terms of parking the vehicles and providing access and workshop space.

Because the Air/Raft doesn't use its headroom, it's not as efficient. This is similar to an ordinary car garage with a convertable in it compared to a van. (having said that, an *enclosed* Air/Raft would still be able to fit into a standard Air/Raft hanger, as might one that was a little larger than standard, such as a 6 seat version, at the Referee's discretion.)

However, I suggest you ignore the "form fitting" reference in regard to the two standard vehicle bays.

Edit:

Been scouring through various old Traveller products, and if you go way back to the original Book 2 before MegaTraveller confused things with megalitres and such, it's pretty clear that while ships are expressed in "mass displacement" terms, it is the actual mass that matters (which makes a lot more sense than volume!) An Air/Raft that *masses* 4 tons takes up 4 tons of mass displacement.

In other words, what the Book 2 (and OT High Guard, and by descent the MGT) design sequence produces is a vessel of a given *mass*. They could be of any volume, really, but for ease of use a standard volume based on liquid hydrogen is used. It's a fudge, but a fair one for ease of play.

On top of all that, the original instruction for deckplans was to allow a leeway of plus or minus 20%, indicating that *volume* was definitely a secondary consideration to *mass* (which was non-negotiable)