Avispa Light Tank (30-ton GM 120 Fusion Engine Tank)

[Cipher]

As a rule, the idea of taking fusion engines mounted inside tanks to power BattleMechs was a common one during the Succession Wars, while the reverse was normally unheard of.

The Avispa Light Tank is an exception to said rule.

During the First and Second Succession Wars, the massive battles that saw entire regiments destroyed left enormous amounts of dubious quality salvage. With dwindling manufacturing and transport capacity, every effort possible was taken to repair and re-use that resource. No matter how much labor and time refurbishment required.

Yet in certain edge cases, fusion engines might no longer be serviceable inside a 'Mech despite being brought back to operation. Whether due to their now poor condition not able to handle the rigors of BattleMech movement, repaired battle damage altering their sustained performance, or some change to their physical dimensions, the end result was the same.

An useless, formally written off engine that could still provide power.

With the popularization of tanks like the Scorpion, it did not take long for desperate Techs to mount written off fusion engines into disabled and severely damaged vehicles. Commanders forced to contend with attrition measured in battalions lost per day were hardly going to ask exactly how their ToE had increased after punishing losses, and crews manning said 'new' tanks that mounted more armor and weapons kept their mouths shut if they realized the source of their new rides.

While the vehicles like the Avispa weren't unique to the Free Worlds League and can be found serving as early as 2819, the League was the first Successor State to give it an official service designation and thus is considered the 'originator' of the 30-ton tank.

The Free Worlds League had fallen into dire straits in the early 2840's, with ComStar War and the subsequent interdiction leaving the state reeling. With logistics and communication issues requiring years to solve even with restored HPG service, improvisations had became common. Frustrated officers would give permission to their technicians do whatever it took to get more fighting machines into the field. 

With the Wasp and Stinger having low survivability in fixed defensive missions, more than a handful of enterprising commanders would take excess engines that were still perfectly suitable for BattleMech use and have them 'reinspected' and written off. Of course, wiser officers would restrict this practice to battlefield captures of unknown provenance, rather an units from official supply chain that had proper factory and servicing reports available.

By 2857 the 'modified Scorpion mounting unsuitable GM fusion engine' had become widespread enough in the FWLM that Colonel Lucia Marik-Ortiz, a future Quartermaster General, would throw her hands in the air and give the type official approval. The now sanctioned 'Avispa' would continue to be converted for the rest of the Succession Wars, though with a sharp decline in popularity after the 2880's. 

'In 'Legacy of Lostech: Documentary of the Succession Wars Field Refits and Rebuilds' Colonel Ron 'Big Iron' Hip, the Commander of the Ron's Red Rangers, would characterize the Avispa thusly; "The Spanish Wasp*? It's a poor man's Manticore, which ain't bad for half the weight. Not as useful as a 'Mech 'course, but you're not using a real 'Mech engine to make it!"

The A301 was the first officially sanctioned variant that was used by the FWLM.

Making use of the in-built heat sinks, the Class Five Autocannon is swapped for a Large Laser. A four-tube SRM launcher and a five-tube LRM launcher, each fed by a single ton of ammo are also mounted in the turret. Typically the cuts and additions needed will ruin environmental sealing if care isn't taken, if the sealing was functional to begin with. Only the bow mounted machine gun is retained with its ammunition supply unchanged. Model of the weapons used in the A301 varied even in the League.

Protection is improved significantly, with six and half tons of plate allowing the Avispa to frontally survive pair of PPC blasts. The increased weight of the turret and hull are compensated via doubling of the rear and front suspension elements, using spares or purpose fabricated parts.

The Scorpion chassis copes well enough with the added mass, aside from increased wear on tracks and the bogies. Mobility is unchanged apart from increase in operational range, the GM 120 rated fusion engine allowing the 30-ton tank to keep up with most heavy BattleMech formations.

The workmanship of the Avispa is as variable as its makers, with some being as good as a re-conditioned Scorpion based machine can possibly be. Others are ramshackle affairs barely fit for battle. One the latter cases is used for reference in this document, and should not be taken as a definitive example of the type.

A302 was identical to the A301, only differing in swapping the SRM launcher and ammunition with another five-tube LRM launcher and ton of ammo for it, enhancing the long range capabilities of the Avispa. A303 was the reverse of A302, swapping the LRM launcher with a second four-tube SRM launcher for greater short-range punch.
 
The Avispa would be used officially by every Successor State apart from Draconis Combine, where such conversions were disdained as 'unworthy of samurai' and were thus relegated to  'battlefield captures'**. Mercenary units strapped for cash will often take bone-stock Scorpions and mate them with salvaged or heavily worn GM 120s, with fusion engines from destroyed pirate 'Mechs being a common pick.

Series of small production runs of factory quality Avispas would occur between the 3030's and 3050's in the Capellan Confederation. Said tanks suffered none of the typical assembly quality issues of the Quickscell parent machine, with adequate sealing and sufficient quality control for a second-line combat vehicle.

Taking into account the improvised nature of the Avispa conversion, almost anything can be found mounted in an Avispa, even if the Manticore-like layout is often the default option.



*Common term for the Avispa, as using the 'official' name can cause confusion for Spanish speakers.
**DCMS units never facing tanks would occasionally 'capture' Avispa-type tanks after battling Stingers or Wasps.

Code: [Select]

Avispa Light Tank A301 (2857)

Mass: 30 tons
Movement Type: Tracked
Power Plant: GM 120 Fusion
Cruising Speed: 43.2 kph
Maximum Speed: 64.8 kph
Armor: Standard
Armament:
     1 Machine Gun
     1 LRM 5
     1 SRM 4
     1 Large Laser
Manufacturer: Unknown
     Primary Factory: Unknown
Communication System: Unknown
Targeting & Tracking System: Unknown
Introduction Year: 2857
Tech Rating/Availability: E/X-E-D-D
Cost: 789,750 C-bills

Type: Avispa Light Tank
Technology Base: Inner Sphere (Introductory)
Movement Type: Tracked
Tonnage: 30
Battle Value: 572

Equipment                                          Mass
Internal Structure                                    3
Engine                       120 Fusion              6
Cruising MP: 4
Flank MP: 6
Heat Sinks:                   10                      0
Control Equipment:                                  1.5
Power Amplifier:                                    0.0
Turret:                                             1.0
Armor Factor                  104                   6.5

                          Internal   Armor   
                          Structure  Value   
     Front                   3         23   
     R/L Side               3/3      20/20   
     Rear                    3         18   
     Turret                  3         23   


Weapons
and Ammo                      Location    Tonnage   
Machine Gun                    Front        0.5     
LRM 5                          Turret       2.0     
SRM 4                          Turret       2.0     
Large Laser                    Turret       5.0     
LRM 5 Ammo (24)                 Body        1.0     
SRM 4 Ammo (25)                 Body        1.0     
Half Machine Gun Ammo (100)     Body        0.5

Features the following design quirks: Poor Workmanship, Poor Sealing, Trailer Hitch
     
   
Notes: Because you gotta do something with those Wasp and Stinger engines that have been rebuilt so many times that they resemble patchwork quilts, right?
For Succession Wars era, not something you do if you don't have to. Unless you really hate Bug 'Mechs or need something to hold the line, that is.

[AlphaMirage]

I'd probably drop turret armor to 16 and add 7 to the front but other than that it's a solid little tank.

[Cipher]

I'd probably drop turret armor to 16 and add 7 to the front but other than that it's a solid little tank.

I kept the turret armor the same as the hull front glacis out of (irrational) need to make my turreted tanks have same frontal protection when hull down. 
-------------------------

Especially early on, Avispa tanks were less comprehensive in their modifications. With limited resources and time during the First and Second Succession Wars, many technicians opted for easy, quick and dirty solutions to improve firepower and protection even if the end result was rather mediocre.

Rather than change the main gun, the Class Five Autocannon and the machine gun are kept as is. Instead a pair of holes are cut in the turret front, typically one on each side of the main gun. Two medium lasers, of whatever type available on hand, are mounted with usually fairly limited traverse.

This improves the close range firepower significantly, although often only one laser can fire if the target gets close enough to the tank. Armor is typically improved to six and half tons, and otherwise these autocannon Avispas are very similar to their brethren.

Of course, Avispa like tanks are not truly standardized and thus this 'Early' type of Avispa is still made when decent enough will do the job or access to components and tooling is lacking.

Code: [Select]

Avispa Light Tank Early (2839)

Mass: 30 tons
Movement Type: Tracked
Power Plant: GM 120
Cruising Speed: 43.2 kph
Maximum Speed: 64.8 kph
Armor: Standard
Armament:
     2 Medium Laser
     1 AC/5
     1 Machine Gun
Manufacturer: Unknown
     Primary Factory: Unknown
Communication System: Unknown
Targeting & Tracking System: Unknown
Introduction Year: 2839
Tech Rating/Availability: E/X-E-D-D
Cost: 741,000 C-bills

Type: Avispa Light Tank
Technology Base: Inner Sphere (Introductory)
Movement Type: Tracked
Tonnage: 30
Battle Value: 520

Equipment                                          Mass
Internal Structure                                    3
Engine                        120 Fusion              6
Cruising MP: 4
Flank MP: 6
Heat Sinks:                   10                      0
Control Equipment:                                  1.5
Power Amplifier:                                    0.0
Turret:                                             1.0
Armor Factor                  104                   6.5

                          Internal   Armor   
                          Structure  Value   
     Front                   3         23   
     R/L Side               3/3      20/20   
     Rear                    3         18   
     Turret                  3         23   


Weapons
and Ammo                      Location    Tonnage   
Machine Gun                    Front        0.5     
AC/5 Ammo (20)                  Body        1.0     
Half Machine Gun Ammo (100)     Body        0.5     
2 Medium Laser                 Turret       2.0     
AC/5                           Turret       8.0

This designs features the following quirks: Poor Sealing, Trailer Hitch     


Note: What I like to think as the Scorpion+ variant, the early form of the Avispa. Suckier than the later ones, but still better than the basic Scorpion.

[Hellraiser]

Its cute, like a half-sized Manticore.

I see a variant in my mind....  The ultimate in Sniper + Anti-Infantry Combo

PPC Turret
5 MG Turret
1 MG Per Arc
100 Shots

[Daryk]

I like this mini-Manticore!  :)

My take on a fusion powered Scorpion is here: https://bg.battletech.com/forums/index.php/topic,50620.0.html

[Giovanni Blasini]

Not bad.  Digging both variants.

[DevianID]

What about a long range patrol craft version of the Avispa, with infantry support integrated.  I can see that being a useful reason to use the stinger engine in a vee.

[Giovanni Blasini]

What about a long range patrol craft version of the Avispa, with infantry support integrated.  I can see that being a useful reason to use the stinger engine in a vee.

A three-ton infantry compartment would be easy enough to add if you dropped one of the two missile launchers, I suppose.

[Cipher]

What about a long range patrol craft version of the Avispa, with infantry support integrated.  I can see that being a useful reason to use the stinger engine in a vee.

So a Goblin-clone with one squad:
-----------------------
The A306 was one the later sanctioned variants that saw service with the FWLM during the Second Succession War, originally intended to provide recon teams with organic firepower to deal with 'Mechs and tanks.

Designed to mimic the infantry carrying capacity of the Goblin tank, the A306 downgrades the usual short range four-tube launcher to a twin-tube model. Typically ammunition carried for the small launcher will be standard short-range missiles, with a few salvos of Smoke and Inferno missiles to provide flexibility if available.

The saved weight goes towards a mild extension of the rear hull, which overhangs the idler wheels but doesn't affect ground mobility in most circumstances. The added space allows for somewhat tight if tolerable seating for a squad of foot-bound infantry and a bare-bones rack for their personal equipment. Some vehicles spoil their troops with power pack chargers.

Often a very simple voice-only intercom is installed, allowing the passengers to talk to the vehicle crew and optionally a small periscope is added to allow the squad lead to spot any dangers before ordering dismount. Exiting is slightly more difficult than with most dedicated APCs but still well within the norm, with the rear-door allowing for safe dismount.

As far as Goblin substitutes go, the A306 and its copycats are fairly popular for their increased firepower if not comfort.

Code: [Select]

Avispa Light Tank A306 (2861)

Mass: 30 tons
Movement Type: Tracked
Power Plant: GM 120
Cruising Speed: 43.2 kph
Maximum Speed: 64.8 kph
Armor: Standard
Armament:
     1 Machine Gun
     1 SRM 2
     1 LRM 5
     1 Large Laser
Manufacturer: Unknown
     Primary Factory: Unknown
Communication System: Unknown
Targeting & Tracking System: Unknown
Introduction Year: 2861
Tech Rating/Availability: E/X-E-D-D
Cost: 724,750 C-bills

Type: Avispa Light Tank
Technology Base: Inner Sphere (Introductory)
Movement Type: Tracked
Tonnage: 30
Battle Value: 550

Equipment                                          Mass
Internal Structure                                    3
Engine                        120 Fusion              6
Cruising MP: 4
Flank MP: 6
Heat Sinks:                   10                      0
Control Equipment:                                  1.5
Power Amplifier:                                    0.0
Turret:                                             1.0
Armor Factor                  104                   6.5

                          Internal   Armor   
                          Structure  Value   
     Front                   3         23   
     R/L Side               3/3      20/20   
     Rear                    3         18   
     Turret                  3         23   


Weapons
and Ammo                      Location    Tonnage   
Machine Gun                    Front        0.5     
LRM 5                          Turret       2.0     
Large Laser                    Turret       5.0     
SRM 2                          Turret       1.0     
LRM 5 Ammo (24)                 Body        1.0     
SRM 2 Ammo (50)                 Body        1.0     
Half Machine Gun Ammo (100)     Body        0.5     
Infantry                        Body        1.0     

This designs features the following quirks: Poor Sealing, Trailer Hitch
Notes: Pretty straight forward, you still get an SRM2 for smoke and infernos.

A three-ton infantry compartment would be easy enough to add if you dropped one of the two missile launchers, I suppose.

The 'spam in a can' version:
--------------------------
Not all attempts to turn the Avispa into an infantry carrier were as successful as the A306, however. Rejected service classification in 2870's by the FWLM, the Avispa Infantry Support Tank and its kin are flawed infantry carriers.

The physical dimensions of the base hull when combined with the increased weaponry and space taken by the fusion engine require 'creative' measures to be taken for an entire platoon of infantry to be carried. The rear of the vehicle is extended so far beyond the original tracks that it would cause the vehicle to get stuck in rough terrain or steep hills if it wasn't accounted for.
 
The rather effective if inelegant solution employed is the addition of another pair of road wheels, requiring the extension of the tracks, the relocation of the idler wheels and even further modifications to the hull. As a consequence of this these vehicles require more maintenance, as the alterations violate the design specifications of the drive-train and cause additional wear and tear. Some crews choose to add a pair of tail skids on both sides of the infantry compartment doors for additional insurance against ditches and trenches.

However, even with the elongated hull not enough space is created for an entire platoon. Thus the compartment is also extended upwards in the rear, which restricts the firing arc of the turret to 270° and means that the Avispa Infantry Support tank cannot fire directly rearwards.This blind-spot is part of why it was denied certification, as the vulnerability was deemed too large for urban combat.

Employing the unorthodox combination of a pair of elevated conventional bench seats and a middle section with semi-standing seats, a full platoon of 28 'footsloggers' can be carried in discomfort and under claustrophobic conditions. It isn't uncommon for soldiers to suffer panic attacks and faint inside these vehicles, as the air can grow stale quickly if powered ventilation is neglected. Noise and smoke entering the compartment are a common source of complaints as the insulation and sealing are rarely redone well, if at all.

While the two squads in elevated seating can exit via the rear doors, to theoretically speed up the dismounting process, hatches are commonly added to the ceiling. This exposes those troops to enemy fire if they slowly use the built in steps to climb down safely, while jumping down can sprain or break ankles. In practice the roof exits, if present, are only used in actual emergencies.

The dire ergonomics of the infantry space, the slow or risky disembarkation process compounded by a total blind-spot render these vehicles unpopular with those assigned to them.

Code: [Select]

Avispa Light Tank Infantry Support Tank (2891)
Mass: 30 tons
Movement Type: Tracked
Power Plant: GM 120
Cruising Speed: 43.2 kph
Maximum Speed: 64.8 kph
Armor: Standard
Armament:
     1 Machine Gun
     1 SRM 4
     1 Large Laser
Manufacturer: Unknown
     Primary Factory: Unknown
Communication System: Unknown
Targeting & Tracking System: Unknown
Introduction Year: 2891
Tech Rating/Availability: E/X-E-D-D
Cost: 711,750 C-bills

Type: Avispa Light Tank
Technology Base: Inner Sphere (Introductory)
Movement Type: Tracked
Tonnage: 30
Battle Value: 515

Equipment                                          Mass
Internal Structure                                    3
Engine                        120 Fusion              6
Cruising MP: 4
Flank MP: 6
Heat Sinks:                   10                      0
Control Equipment:                                  1.5
Power Amplifier:                                    0.0
Turret:                                             1.0
Armor Factor                  104                   6.5

                          Internal   Armor   
                          Structure  Value   
     Front                   3         23   
     R/L Side               3/3      20/20   
     Rear                    3         18   
     Turret                  3         23   


Weapons
and Ammo                      Location    Tonnage   
Machine Gun                    Front        0.5     
SRM 4                          Turret       2.0     
Large Laser                    Turret       5.0     
SRM 4 Ammo (25)                 Body        1.0     
Half Machine Gun Ammo (100)     Body        0.5     
Infantry                        Body        3.0     

This designs features the following quirks: Poor Sealing, Poor Workmanship, Bad Reputation, Trailer Hitch

Notes: Hey, it gets the job of transporting a platoon of PBI from point A to point B done! That's if you're fine treating your soldiers like sardines. And don't care that they sometimes get shot while dismounting. And also that they're going to be plotting your demise afterwards.

Bit more seriously, the seating is inspired by a proposed airliner semi-standing seat concept crossed with a folded-out tool-box. Since I'm not sure how else you'd fit a platoon into a modified Scorpion hull.

[Daryk]

I figured out seating for the full 50 in a Kurita Goblin once... the crew (including the driver) have to be in the turret...