’Mech Manual: Thunderbolt TDR-5S

The Thunderbolt TDR-5S was introduced in 2505 as an upgrade to the Capellan Confederation’s TDR-1C. It proved to be a popular design thanks to its rugged construction and ability to fill a range of battlefield roles. It spread throughout the Inner Sphere and Periphery during the Star League and remained in widespread use through the Jihad. During the Republic era and Dark Age, it has been replaced by more modern designs except in the Periphery and with down-on-their-luck mercenaries.

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  • You can fulfill multiple roles: fire support, sniper, or brawler
  • Fire either your long-range weapons or your short-range weapons. If you fire everything, you’ll cook yourself.
  • You’re slow enough that standing in a defensive position while working as fire support or a sniper is almost as good of protection as evasive maneuvering.

Thunderbolt TDR-5S

  • Role: Brawler
  • Tech Base: Inner Sphere (2505)
  • Chassis: 65 tons
  • Movement: 4 / 6
  • Armor: 208
  • Heat Sinks: 15 (15)
  • Weapons:
    • LRM 15 (ammo: 16)
    • Large Laser
    • Medium Laser × 3
    • SRM 2 (ammo: 50)
    • Machine Gun × 2 (ammo: 200)
  • Design Quirks:
    • Multi-Trac
    • Rugged (2)
    • Ubiquitous
  • Cost: 5,413,760 C-Bills
  • Battle Value: 1,335


The Thunderbolt TDR-5S has fairly average mobility for a heavy ’Mech. It has a walking speed of 4, a running speed of 6, and no jump jets. That is only enough to generate a maximum target movement modifier of +2, so it can be just as useful defensively to stand in a position that gives a terrain bonus such as a hex of woods or partial cover.


The TDR-5S is a well-armored design. It’s almost maxed-out 208 armor points is above average for a heavy ’Mech even though it falls into the lighter half of the weight class. A weakness is that it carries a lot of ammunition. The right torso has 20% of its critical slots explode, the center torso 17%, and the left arm 14%. Taking an unlucky critical hit in any of those locations can quickly reduce a Thunderbolt to scrap despite its thick armor.


The Thunderbolt TDR-5S carries a mix of weapons that allow it to fill multiple roles on the battlefield. The LRM 15 and large laser come into range at 21 and 15 hexes. At those ranges, the Thunderbolt can offer indirect fire support with the missiles or act as a sniper. Then at 9 hexes, it can add a trio of medium lasers and an SRM 2. Finally, it carries two machine guns that can add a bit of damage up close and give it the ability to quickly handle enemy infantry. While the LRMs have a minimum range, the short-range weapons make up for that and allow the Thunderbolt to get more dangerous as the range to its targets decreases. It also benefits from the Multi-Trac quirk that lets it split its fire between targets without penalty as long as they are all in its forward or arm firing arcs.

Maximum and Expected Damage

Because the SRM is a relatively small component of the Thunderbolt’s overall firepower, it makes a good candidate for special ammunition. If the TDR-5S’s mission requires facing a large number of infantry or conventional vehicles, then Inferno missiles can be a good choice.

Most of the weapons on the TDR-5S are mounted on its torso. That has the benefit of meaning those weapons are less likely to be lost during battle, but it restricts their firing arc. The two exceptions are the large laser on the Thunderbolt’s right arm, and the pair of machine guns on its left arm. Those two weapons enjoy extended firing arcs that mean the TDR-5S can bring an effective weapon to bear in almost any direction whether it is facing an armored target or infantry.

Maximum Damage for Firing Arcs

The TDR-5S requires ammunition for some of its weapons, but it carries enough that it doesn’t need to worry much about running out of shots. The LRM launcher’s 16 shots are enough to fire every round in most battles, while the SRM and machine gun bins will likely last through several engagements.

Heat Management

Heat management is critical when piloting a TDR-5S. It carries 15 single heat sinks, but its weapons can generate 24 heat in a single round. When combined with a potential movement heat of 2, that means the Thunderbolt can overheat by 11 points in a single round. As a result, the MechWarrior will need to manage which weapons they fire each round to optimize the damage they can deal without generating too much heat.

In practice, this means that they should use the large laser and LRM 15 at targets 7 or more hexes away, and then move to the three medium lasers and alternating fire with the large laser as the range decreases. The middle area of 4-6 hexes can have a different ideal weapon mix at each range due to the particular range brackets for the weapons. Depending on how much a MechWarrior is willing to push up heat, they can add additional weapons to the set fired, but that means they’ll need to fire less on a later turn in order to cool back off.

RangeIdeal Weapons
7+ hexesLarge Laser, LRM 15
6 hexesLRM 15, Medium Laser × 3
5 hexesLarge Laser, LRM 15
4 hexesLarge Laser, Medium Laser × 2
3- hexesMedium Laser × 3, Machine Gun × 2, Large Laser (every other round)
Heat-Adjusted Maximum and Expected Damage


The Thunderbolt TDR-5S is an effective brawler. Both arms have fists that can hit for 7 damage. Punching with either arm does require sacrificing a weapon attack though. The left’s machine guns are an easy trade off, but the large laser in the right arm can deal more damage with a better chance to hit than a punch. That tradeoff can make sense though if the Thunderbolt is running hot since a 7 damage punch without any heat generated can be less of a problem for its heat sinks than a laser beam that will only deal 1 more damage but generate 8 points of heat. When kicking, the Thunderbolt deals 13 points of damage.

Cost & Upkeep

The TDR-5S uses intro tech components, so it enjoys a low price. The Rugged and Ubiquitous quirks mean that it requires maintenance less often and replacement parts are easy to find when needed. At least one LRM ammo bin will usually need to be replaced each battle, but second half of the LRM ammo, the SRM ammo, and especially the machine gun ammo will need less frequent reloads.

When using the Warchest Point system, these are the expected costs for the Thunderbolt TDR-5S:

Purchase650 SP
Armor Repair65 SP
Structure Repair130 SP
Reload5-20 SP


The new plastic version of the Thunderbolt is included in the A Game of Armored Combat set. Iron Wind Metals produces a metal version of the same sculpt.


More ’Mech Manuals

By Scott Boehmer

A game enthusiast and software engineer.

3 replies on “’Mech Manual: Thunderbolt TDR-5S”

Really nice breakdown of a good ‘ol Classic. The Thud is a really solid Swiss army knife/Jack of all trades ‘Mech as it really can do everything, and its tanky enough to take a hammering too!

Excellent analysis, much appreciated.

How do you work out your expected damage?

For example, on your charts you can see the LRM in isolation towards the 16 to 21 range. It appears to show minimal expected damage while max. damage at 15 looks ok. I though it would be more like 6-7 expected damage based on a the modifiers at long range with a standard IS gunnery skill.

For expected damage, I use base target numbers of 6 (short), 8 (medium), and 10 (long). The +2 from the default gunnery of 4 is meant to represent some movement or terrain impacting the shot. In addition to that roughly 17% chance to hit at long range, the LRM 15 also sees a lower expected damage due to the cluster roll meaning that even when it does hit, it is likely going to do less than 15 damage.

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