If you follow me on Bluesky, I know I said this article would cover Compact Gyroscopes and Compact Engines. I lied. We’re doing Compact Gyroscopes, Heavy Duty Gyroscopes, XL Gyroscopes, and Armored Components (Gyroscopes). Gyros, like Engines, are a real nuisance to talk about in terms of ‘Mech design because we can’t really talk about them in terms of what weight class you’re building. Instead, they have to be discussed in terms of Engine Rating, because that’s what determines how much they weigh.

The XL Gyroscope is an okay way to save 1-2 tons at the cost of taking up 2 extra critical slots. Compact Gyroscopes are intended to be a way of protecting your Gyroscope from Critical Hits by making it a little heavier and a 2 slots smaller. Heavy Duty Gyroscopes take a different approach with the same objective: they take up the same number of slots, and have a different series of damage effects. On the first hit, there’s no PSR but they suffer a +1 to future PSRs. The second hit is the normal effect of the first hit on standard gyros (PSR on hit, +3 on future PSRs, forces PSRs when running or jumping), and the Gyro takes a third hit to be destroyed.

Armored Components is getting included in this article because it’s a rule that lets you spend ½ a ton per crit slot of a piece of equipment to add one point of armor per slot. This is going to be relevant here because we’ll be comparing the effectiveness of just armoring your Gyro as opposed to upgrading to either a Compact or Heavy Duty Gyroscope.

Let’s get these out of the way first, since they’re solving a different problem entirely from the rest of the Gyroscopes. As I’ve discussed in other articles, the best way to save weight in a design is your Engine, the second-best is your Structure, and, previously, I’ve said that Armor choice is third place. I was wrong about that… sort of.

If you put Ferro-Fibrous armor on an Inner Sphere ‘Mech, even on a 20-ton ‘Mech, it can potentially save you half a ton at the cost of 14 critical slots. On a 95 or 100 ton ‘Mech, it can save up to 2 tons. Compared to XL Gyroscopes, which save a minimum of 0.5 tons to a maximum of 2 tons for an extra two Crit Slots.

The difference is the Ferro-Fibrous Crit Slots aren’t themselves vulnerabilities (they just increase the danger faced by other components), whereas suffering a Gyro hit can be crippling and two extra crit slots dramatically increase the risk of that happening. So how much is that risk actually increased by?

Let’s assume that the Center Torso of a ‘Mech contains a Standard Engine (6 slots), a Standard Gyroscope (4 slots), and the other two slots are equipment or weapons of some sort. For convenience, we’re only going to compare attacks on the front/rear arcs.

Under the Standard Critical Hits rule, rolling a 2 on location is a a Through Armor Critical (TAC) assigns that hit to the Center Torso, a 1 in 36 chance (2.78%). Assuming the CT’s armor is stripped, that means the chance of hitting CT is 7 in 36 chance (19.44%). Then, once there’s a roll on the Critical Hit Table, it’s a 61.11% chance of scoring a Critical Hit (that’s an average that accounts for the whole range, see table below).

Under this situation, every attack has a 0.57% chance of a TAC applying a crit to a Standard Gyro; if the armor on the Center Torso is gone, attacks have a 3.96% chance of inflicting a Gyro crit. If we replace the Standard Gyro with an XL, these odds go up to 0.85% and 5.94%. That represents a 49.1% to 50.0% increased risk.

Normally, it takes an average of 176 attacks to land a TAC against a Standard Gyro, as compared to an average of 118 on an XL. After stripping armor, that’s around 25 attacks for Standard Gyros down to 17 attacks against an XL.

Floating Crits lower all of these risks substantially, and consequently make XL Gyros safer. The odds of a TAC hitting a Standard Gyro are 0.11% or 3.51% if CT is stripped of armor. That’s 19.3% and 88.6% of the risk presented under the Standard Critical Hits rule. Now, swapping out for an XL Gyro, those odds become 0.17% or 5.26%. That’s an increased risk of 54.5% and 49.9%.

Under Floating crits, it takes an average of 909 attacks to land a TAC against a Standard Gyro, as compared to an average of 588 on an XL. After stripping armor, that’s around 28 attacks for Standard Gyros down to 19 attacks against an XL.

These work in the reverse of XL Gyros: they weigh more but take up 2 fewer slots to reduce the risk of suffering a Critical Hit. For the purposes of these comparisons, we’re assuming the whole rest of the Center Torso is crit-padded.

Every attack has a 0.57% chance of a TAC applying a crit to a Standard Gyro; if the armor on the Center Torso is gone, attacks have a 3.96% chance of inflicting a Gyro crit. Swapping to a Compact Gyro, these odds go down to 0.28% and 1.98%. That represents 49.1% to 50.0% of the initial risk.

Normally, it takes an average of 176 attacks to land a TAC against a Standard Gyro, as compared to an average of 357 on a Compact. After stripping armor, that’s around 25 attacks for Standard Gyros up to 51 attacks against a Compact.

The odds of a TAC hitting a Standard Gyro are 0.11% or 3.51% if CT is stripped of armor. That’s 19.3% and 88.6% of the risk presented under the Standard Critical Hits rule. Now, swapping out for a Compact Gyro, those odds become 0.06% or 1.75%. That’s down to 54.5% or 49.9% of the original risk.

Under Floating crits, it takes an average of 909 attacks to land a TAC against a Standard Gyro, as compared to an average of 1,667 on a Compact. After stripping armor, that’s around 28 attacks for Standard Gyros down to 57 attacks against a Compact.

Heavy Duty Gyros have the same to-hit risk as Standard Gyros, but can withstand an extra hit before being destroyed. The down-side to this is that the first “extra” hit has its own penalty, not as bad as the first hit on most Gyros, but a +1 to future PSRs is still serious.

Since TACs are already so rare, I’ll just focus on regular hits against an unarmored CT here. On average, it takes 25 attacks to score the first crit against a Heavy Gyro (28 with the Floating Crits rule) and 34 attacks to score the second crit (38 with Floating Crits). That means it takes an average of 59 (or 66 with Floating Crits).

So which is better? After losing CT armor, a Compact Gyro takes an average of 51 attacks to suffer its first Critical Hit (57 with Floating Crits). Meanwhile, a Heavy Gyro will have to suffer an average of 59 (or 66) hits to experience the same penalty. But Heavy Duty Gyros experience a partial penalty after an average of 25 (or 28) hits and they’re heavier.

So what other advantage to Heavy Duty Gyros have? It takes 3 hits to destroy one instead of 2 hits. It takes an average of another 101 attacks to score the 2nd Critical Hit against a Compact Gyro (114 with Floating Crits). Meanwhile, the final blow against a Heavy Gyro takes another 51 hits (or 57). So a total of 152 (171) to destroy a Compact Gyro vs 110 (123) to destroy a Heavy Gyro.

While a Heavy Gyro avoids suffering the full effect of its first full Critical Hit (the +3 PSRs, etc.), the fact that it suffers a partial penalty for half of that time kind of stinks, especially given that the Compact Gyro avoids its first hit for around 86% - 88% as long as the Heavy Gyro all while weighing less and taking up fewer crit slots. Comparing duration to fully destroy favors the Compact Gyro, where the Compact Gyro lasts 37% to 39% longer. As long as the Center Torso is fully crit-padded, Heavy Duty Gyroscopes are worse than Compact Gyros where long-term survivability is concerned. Combine that with the fact that they weigh less and take up less space, and they’re a no-brainer.

Armored component rules let you add a single point of armor to a component for each slot that component takes up, adding 0.5 tons per slot of the component. On a Standard Gyroscope, that means adding 2 tons. On a Compact Gyro, it’s only 1 ton.

If you noticed in the earlier table, I included numbers for “GYRO(A)” and “COMP(A)” to indicate Armored variants of the Standard and Compact Gyroscopes. The Armored Compact is the same weight or lighter than the Heavy Duty Gyroscope in all categories except ER 100 or lower. And in that category, the Heavy Duty is only half a ton lighter. Compared to an Armored Standard Gyroscope, it’s the same weight or lighter on ER 300 and lower. For ratings above that, it’s only 1 ton heavier and provides dramatically superior protection.

This means the only use case I would recommend for Heavy Duty Gyros is on ‘Mechs with ER 100 or lower that need to save on tonnage, but have plenty of crit slots to spare.

They’re very close in weight, and the Compact Armored gyro is just better. With Armored Gyroscopes (of any kind), you would need to suffer two crits to the same location to damage the Gyro (one to get through the armor, one to get through the component). With Compact Gyros, that means hitting both slots twice. So we’ll start with that.

Funny enough, we’ve already done the math on hitting one of a pair of slots and then following up with hitting a single slot: that’s the same odds as destroying an unarmored Compact Gyro: an average of 51 attacks to remove one point of armor (57 with Floating Crits), and a total of 152 (171) to destroy a Compact Gyro… sort of. Because it’s also 152 (171) attacks to strip the second point of armor instead of hitting the first crit. But I’ll mention that in the Concluding Thoughts.

So, this article wasn’t the one I planned for this week. Which means I ran into some problems for the research that went into it. Namely, when it comes to calculating odds of destroying Gyroscopes. I cut corners on that, and really what I’ve described are the odds of a gyroscope being taken out in consecutive Critical Hits. And that’s not, practically speaking, the only way they’d be taken out. This especially presents a problem when I start talking about Armored Components and the math for how to predict the destruction of those. That’s why that section ends relatively abruptly.

This table depicts some of the work I started doing to really answer the question of how survivable some of these systems are, and this is what I was going to use to calculate the odds of destroying an Armored Compact Gyro. But we’re already over 2k words for this week, so I think an article on planning for Critical Hits to the Center Torso might need to be its own topic.

Still, I hope you enjoyed the discussion on Gyros! For me, Compact Gyros came out as the real winner. The only question I have now is whether they even need Armored components to beat the odds, or if an Armored Compact Gyro would be so survivable it would always out-live the ‘Mech mounting it.

*EDIT: Turns out MegaMek Lab doesn’t properly display the impact of using Armored Components on your design, and I didn’t properly check TacOps for the rules. Any ‘Mech that uses Armored Components needs to be 3061 or later. If you’re designing in MegaMekLab, it won’t raise your “earliest available” year to match that. So That’s something to be aware of! I tried to correct the article accordingly, but