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Hello all. So I am starting another spreadsheet project. I want to create a sheet that calculates cost and mass for a 'Mech's or vehicle's various components for a parts inventory. The idea is that each 'Mech and vehicle design would have its own inventory sheet for parts exclusive to that design. I want to make a generic inventory sheet, all the user would have to do is put in a few stats, mass, MP, etc. and the sheet would calculate the cost and mass for an individual component. The user would then input a number indicating how many of those components are in the inventory so a campaign player knows how much cargo space he needs to haul his stuff around and how much his inventory is worth.

A lot of parts are generic and used across a range of designs but this spreadsheet is for components specific to a 'Mech design, say the actuator set for the right arm of a Thunderbolt, or at least those that I think should be considered specific to a design. Other people may have different opinions on the subject.

Most components that would need repaired or replaced on a 'Mech or Vehicle has specific masses associated with them, but a few do not: specifically actuators. So how much of a 'Mechs internal structure do you think should be set aside for the actuators? How much of a cockpit's mass is for the sensors? Etc. I'm just looking for peoples' opinions, and any sources of information on the subject I might have missed.

Concerning actuators and internal structure I was thinking I'd just set aside half the internal structure's mass for actuators and divide that half by the number of actuators in the design to get a rough number for an actuator's mass. The other half would be divided by the total number of the design's internal structure circles to get the mass for each of them. That mass would include the appropriate set of myomer bundles etc. for a limb. Thoughts?

For a cockpit I was think a half ton for life support, a half ton for the cockpit itself: controls, ejection seat, monitors, etc. and the remaining amount, depending on whether its a standard or compact cockpit, for sensors. Thoughts?

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First let me say I love this idea

I think the mass for actuators is pretty close, I would go with between a quarter to a third of the mechs internal structure weight for the cockpit mass.

I see something like this 30-50% for actuators depending on if it has arms or not, 25-30% for the cockpit, the rest would be the rest of the supporting structure of the mechs frame.

The thing that can not be forgotten is all the wiring and hoses that are also bundled withing the framing

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To me, 30-50% for actuators sounds high, but I guess that also depends on what you think of as actuators. Mechanically, actuators are going to be hydraulic or electrical cylinders, most often, in some cases rotary high-torque motors. I wouldn't expect them to weigh more than 10% or so of the structure. But, if you count the pivots and structure to the arms and legs themselves, then that percentage would go up a good deal, probably close to that 30% or so figure.

Another question would be if the hydraulic power plant used to operate the actuators would be considered part of the structure itself, or part of the power plant (engine). Power plant, I would think.

I think the book weight for a cockpit complete is fine; the structure supporting the cockpit would just be part of the structure, with mounting points and all.

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Rick
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Thanks for the input guys. Considering all the possible stuff that can go into the internal structure category I think I will go with 30% for actuators and round to 1 decimal place.

Rick I am inclined to say all the hydraulics would be self contained. A recent trend in hydraulic design, at least in aerospace is to make the actuator a completely self-contained unit, all that is needed is electrical power and control wiring. The actuator has its own hydraulic pump and fluid reservoir. Eliminating the tubing system to supply hydraulic power saves a lot of weight. I think an similar system would be fairly commonplace in BattleMech actuators. But that's just my opinion.

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it does not only save weight, but thetubes could get hit, eliminating the tubes reduces the likelyhood of damageing the component, when the wiring is replaced by a bus-System the component just needs to get ist commands and electricity over some connection to work.

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typos and spelling-mistakes are property of the finder. english is not my mother-tongue.

While it's certainly possible to have self-contained hydraulic/electrical actuators, it isn't very efficient. If you're going to send electrical power power to the actuator, there are very efficient electrical actuators to use instead. The main advantage to hydraulics is a central power unit can operate everything, and the actuators themselves can be very small. If each actuator includes an electric motor, hydraulic pump and hydraulic motor or cylinder, that's getting pretty large.

But there's nothing to say the actuators could /not/ be all electric. It's just harder to get really large forces that way.

In any event, regardless of the actual power source, 30% for a total including all actuators, their hinges/pivots/mountings & power source does seem reasonable.

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Rick
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It is also harder to service those hydraulic systems if you have to re-service each one individually. On the F-16, There is one reservoir for the hydraulic systems, with only one servicing point on the plane (I was weapons troop and rarely dealt with the hydraulics system except when dealing with the gun and then only when I hooked it up).

John

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ViperXTC

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Seeing how things are crammed into the structure, I am basing this off how the components are stuffed into the vehicles I drive aka the M1074/1075 PLS, one has to take that into account and add in the weight being spread out over a larger area as well as less then ideal setup leading to other issues and weight as well.

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How far do we want to break this down? I know in the past, we have always assumed that the mass of a weapon (say, 8 tons for an AC/5) includes all the necessary feed system, power, fire control and whatnot. Similarly, a ton of ammo represents not just the ammo, but the physical magazine too, and maybe also part of the feed system.

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Be careful what you wish for. I might let you have it.

My plan is to break it down no further than what is on a record sheet so actuators and internal structure circles for internal structure mass. Armor will be treated similarly; everything else will go by the component mass as stated in TechManual.

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