ghostrider
05/04/15 03:00 AM
76.89.120.217
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It was suggested in another thread that fusion engines did not have different physical sizes while talking about using the xl engines in vehicles and how they did not take different amounts of criticals in different size mechs for different speeds.
If that were true, why could a unit not mount 2 engines in it? Wouldn't 2 smaller engines put out the same power as one large engine would at alot less weight?
And in a vehicle, it wouldn't matter to much about taking up room.
This does sound like a way to cheat, but I am curious why a dual engine system isn't allowed. (Besides the developers don't want them).
I guess another question would be related to this one as well. It is implied that the use of jump jets requires a mech to land after a jump, yet lams in airmech mode are not required to, and use fuel in fighter mode, but not airmech mode. I can see this being part of why they wanted to be rid of it. But why couldn't a jump jet equipped mech stay airborne?
Even jump into an open bay of a hovering dropship.
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Cray
05/04/15 07:13 PM
67.8.171.23
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The basic points are two-fold:
1) Out of character, the rules say you can't. See Tech Manual, which was explicit that you get 1 engine per vehicle.
2) In character, the explanation is that ganging multiple engines together doesn't make the final engine lighter. If you make a 300-rated fusion engine out of two 150-rated reactor cores or four 75-rated engines, you still end up with a 19-ton engine. The reason stems from the exponential weight growth of single combat engines: you need those bigger myomers and transmissions and doohickeys to handle the power output.
But, honestly, it's a lot of fun to make twin-engine 'Mech designs. Suddenly, 5/8 100-ton 'Mechs are almost as easy as 3/5 100-ton 'Mechs. And they're so much more durable.
Jump Jets:
The in-character explanation (in Tech Manual) for jump jets is that they can only fire briefly - like during takeoff and landing - or they'll burn up while super-heating atmospheric oxygen for reaction mass. LAMs and aerospace fighters use more innocuous propellants like hydrogen to avoid that problem.
Of course, it shouldn't be too hard to graft fighter engines to a 'Mech. For get the whole LAM transformer crap, 'Mechs don't need wings to fly with BT's awesome fusion rocketry.
Which leads to the out-of-character explanation: that BattleTech is not meant to be Gundam or any number of other animes where 'Mechs fly around. 'Mechs are walking tanks that can briefly fire rockets to cross terrain obstacles. It doesn't fit the feel of the setting to let 'Mechs fly. So, jump jets only fire briefly. (And LAMs are going extinct.)
But it'd be easy to make flying 'Mechs if you want them.
Mike Miller, Materials Engineer
Disclaimer: Anything stated in this post is unofficial and non-canon unless directly quoted from a published book. Random internet musings of a BattleTech writer are not canon.
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ghostrider
05/08/15 09:16 PM
76.89.120.217
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Just had a thought about multiple engines and why they probably don't allow them.
What would keep someone from installing the smallest engine they could in a unit for the free heat sinks?
Even if they don't hide them all, an engine that is less them 5 tons unit would give you 10 tons of heat sinks for free.
Which actually opens up another question.
How is it possible to have fusion engines under 10 tons with just the heat sinks added? That is not including the rest of the components needed to actually run the engine.
Now as for the see Tech manual, which one?
I guess I might have to actually look it up in the wiki.
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Cray
05/10/15 11:44 AM
67.8.171.23
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Quote:
ghostrider writes:
Now as for the see Tech manual, which one?
There's only been one book titled Tech Manual. I think they're up to the 4th printing, if that matters.
http://www.amazon.com/Battletech-Techmanual-Classic-Catalyst-Game/dp/0979204720
Mike Miller, Materials Engineer
Disclaimer: Anything stated in this post is unofficial and non-canon unless directly quoted from a published book. Random internet musings of a BattleTech writer are not canon.
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ghostrider
05/10/15 11:51 AM
76.89.120.217
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Technical Readouts. I would assume all of them are tech manuals.
But I guess the book you refer to is called Tech Manual.
Sorry, if I didn't get that right off.
I did read in the masters and compendium that only vehicles have that statement under their heading. I guess it was to avoid the smallest fusion engine being use to gain the heat sinks at almost no cost to weight.
Though I would like to know peoples opinions on the minimum weight of a fusion engine. Having the 10 tons of 'free' heat sinks does cause a little concern since a vehicle with a small fusion engine could be less then 10 tons entirely. Same with mechs.
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Cray
05/11/15 06:48 PM
67.8.171.23
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Quote:
ghostrider writes:
Though I would like to know peoples opinions on the minimum weight of a fusion engine. Having the 10 tons of 'free' heat sinks does cause a little concern since a vehicle with a small fusion engine could be less then 10 tons entirely. Same with mechs.
It's an ancient rules convenience with no great fluff explanation. When the game was only about 'Mechs in the early-mid 1980s, providing 10 free heat sinks got every 'Mech started on the same foot. It was useful, since very few 'Mechs short of heavies can afford 10 tons for basic heat sinks. Light 'Mechs are especially borked without a wad of free heat sinks.
While it might be odd in comparison to engine and heat sink weights, it's not breaking gameplay and does keep light 'Mechs in the running.
Mike Miller, Materials Engineer
Disclaimer: Anything stated in this post is unofficial and non-canon unless directly quoted from a published book. Random internet musings of a BattleTech writer are not canon.
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GiovanniBlasini
05/11/15 09:57 PM
76.243.24.105
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Quote:
Cray writes:
Jump Jets:
The in-character explanation (in Tech Manual) for jump jets is that they can only fire briefly - like during takeoff and landing - or they'll burn up while super-heating atmospheric oxygen for reaction mass. LAMs and aerospace fighters use more innocuous propellants like hydrogen to avoid that problem.
Of course, it shouldn't be too hard to graft fighter engines to a 'Mech. For get the whole LAM transformer crap, 'Mechs don't need wings to fly with BT's awesome fusion rocketry.
Which leads to the out-of-character explanation: that BattleTech is not meant to be Gundam or any number of other animes where 'Mechs fly around. 'Mechs are walking tanks that can briefly fire rockets to cross terrain obstacles. It doesn't fit the feel of the setting to let 'Mechs fly. So, jump jets only fire briefly. (And LAMs are going extinct.)
But it'd be easy to make flying 'Mechs if you want them.
Use jump jets or improved jump jets, must jump a minimum of 3 (or, for higher grav worlds, 1.5 times current gravity), and uses fuel at, say, twice the amount of an aerospace fighter? Maybe require partial wings if you want to fly as something other than a VTOL or Spheroid?
Member of the Pundit Caste
"Which side are we on? We're on the side of the demons, Chief. We're evil men in the gardens of paradise, sent by the forces of death to spread devastation and destruction wherever we go. I'm surprised you didn't know that." -- Col. Saul Tigh, BSG2003
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ghostrider
05/12/15 03:28 AM
76.89.120.217
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Getting slow in my old age.
If jets only fire when the lift or land, how would you steer in flight?
This becomes more of a problem with odd things like shields. And I don't know if they finally limited just how many times jets can be used, but last I knew, jets didn't have a limit on their use.
The fluff of the tarantula pretty much states the jets fire through the entire jump cycles since it says it moves it's legs to direct it's course. So that makes it sound like they do not need to be shut off.
And it would be difficult to change direction of not only flight, but landing a mech as well. The mech shuffle should be impossible without the jets firing the entire time.
As for the free heat sinks and engine weight. I do not see any real reason why there should not be a minimum weight to an fusion engine. The volume of space a fusion engine takes decides how many heat sinks it can hide, yet it does not matter if they are single or double heat sinks. I know double heat sinks came later, but it does show just how badly the way fusion engines don't follow their own rules.
It suggest that space or crits does not conform when figuring engine space.
A prime example would be an engine that can fit 10 standard heat sinks would only fit 5 double heat sinks, and that would be clan ones.
It also asks why a half ton engine can negate the weight of those heat sinks that are 'free'.
Is it magic, that does this?
Or did they use an anti gravity device we don't know about.
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DavidG
06/26/15 09:38 PM
96.29.193.32
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Just saw this thread and thought I'd lend my two-cents worth in. The reason for not having twin or more engines in mechs and other vehicles has to do with real world physics. I can give an example form railroad locomotives. Locomotives are actually mobile power plants. They use a diesel engine that produces a variable amount of horsepower based on how many RPMs it is set up to work at. An example would be a EMD 16-645, a 16 cylinder engine, which produces up to 3600hp with a turbo charger, and 2000hp with out. Railroads tried multi engine locomotives, but they always ended up larger than a standard locomotive with one engine. That is because each engine has to have it's own control system, generator to convert horsepower to kilowatts, etc. This doubling up of components leads to a larger locomotive to house them. An example was the DDA40X produced for the Union Pacific railroad. It had 6600hp from twin engines (2 16-645 rated at 3300hp) These engines were around 98 feet in length. The trouble was if one system had a failure the whole locomotive had to be taken out of service. So U.P. decided to standardize on 3000hp single engine locomotives, which were smaller and weighed less. This was 45 years ago, today the standard engine is 4300 to 4400hp. The other reason is smaller engines don't hold up to the stresses that larger engines do.
So putting this in Battletech terms, a twin fusion engine mech would require double the cooling systems, double the power conversion systems and controls systems. Which is double the problems and double the chances of something breaking which takes the mech out of service and possibly dead if it happens on the battlefield. I hope this helps.
DavidG
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ghostrider
06/27/15 01:56 AM
76.89.120.217
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Battle tech and the real world having issues deals with things like high powered lasers and such. Part of the idea of having 2 engines is so one can power weapons without drawing so much power from the original engine.
Also it was a way to 'cheat' A half ton fusion engine comes with 10 heat sinks. The engine doesn't cover the criticals for it, but you basically gain 9.5 tons of heat sinks for free.
Also the game doesn't have an issue with how much power is pulled from the engine to power anything but movement. If you have to power a small city with the diesel engine while pulling a max loaded train, how would that affect the speed of it? Would it be able to keep at top power output, not just speed but pulling power?
And space isn't that big of an issue, as the standard fusioin engine fits in the center torso of a mech. Doesn't matter the size or rating, which is another issue I have. Why could you not have a small one run the weapons and other things and allow the main one to move the unit exclusively?
Besides the rules say you can't. This is to see if there is another reason other then they say so.
Thinking about it the hybrid cars come to mind. The gas engine kicks in for power and recharge the batteries. This could be used as an example.
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