Bullets vs Beams for Gunpods : What are the advantages and disadvantages?

[cheemingwan1234]

Okay, we know that in Macross, before Frontier, VFs have conventional bullet spitting autocannons as their gun pods, but later on with the VF-27, they switched to beams. What are the advantages and disadvantages of using conventional projectile gunpods and beam gunpods?

Edited November 21, 2022 by cheemingwan1234

[talonlm]

Pure speculation (it is, after all, sci fi); maintenance, reliability, weight and accuracy.   Beam weapons would have fewer moving parts to fail.  A lot less dirty.  Mechanism for discharging a gun pod would be complex and heavy.  Lots of work to keep a gun pod running right (cleaning, timing, barrel life, etc).  Doesn't take much fouling or a timing error or even something as simple as too short of a trigger pull to jam up a gun pod.  Few things are as dense as ammunition . . . but, without knowing how the beam weapons are powered, batteries / power supplies would be one of those 'few things,' so maybe, maybe not here.  Recoil from a beam rifle would be minimal, easing target acquisition / re-acquisition and maintaining SA on the target. 

[Seto Kaiba]

2 hours ago, cheemingwan1234 said:

Okay, we know that in Macross, before Frontier, VFs have conventional bullet spitting autocannons as their gun pods, but later on with the VF-27, they switched to beams. What are the advantages and disadvantages of using conventional projectile gunpods and beam gunpods?

Beam gunpods are something that's been flirted with before that.

The earliest example belonging to an in-continuity Macross title is Macross: Eternal Love Song from the Macross II timeline giving the VF-4 a beam gunpod.

As to the advantages and disadvantages... it's a balancing act.

Variable Fighters, Battle Pods, etc. are made of, and armored with, extremely tough composite materials that have excellent resistance to heat and ablation and are reinforced with energy conversion armor to make them more resistant to impacts and explosions.  Human-built mecha have increasingly supplemented that defensive ability with special ablative anti-beam coatings to provide additional protection from laser and particle beam weapons.  Energy weapons have to overcome those defenses by brute force, while cannons that fire hard rounds and missiles with explosive warheads circumvent part of that defense using special armor-piercing warheads that can defeat energy conversion armor.

The first three generations of Variable Fighter didn't have a lot of surplus generator output to work with.  Their initial-generation thermonuclear reaction turbine engines were a lot less efficient than the thermonuclear reaction burst turbines developed for 4th Generation VFs or the Stage II engines developed for 5th Generation VFs.  Most of their power was either going to thrust generation and other propulsion loads (arcjet verniers, etc.), to energy conversion armor, or to active stealth.  They didn't have enough power to equip the VF wtih an energy weapon that was as effective against energy conversion armor as a conventional cannon using OTM propellants and anti-ECA rounds.  An OTM-improved modern rotary cannon was a lot simpler, cheaper, and more robust than a beam weapon.  By making them out of OTM composites and using more powerful OTM propellants they had an EMP-hardened cannon that could hit many times harder than a conventional air-to-air or anti-tank rotary cannon and reliably defeat energy conversion armor while requiring very little energy to run.

4th Generation VFs benefitted from a new model engine that had superior thermoelectric converter technology.  However, that improvement in generator output was once again devoted mainly to defensive systems like the energy conversion armor, active stealth, and the newly-introduced pinpoint barrier.  

It wasn't until the Stage II thermonuclear reaction turbine engines were introduced for 5th Generation VFs that the amount of surplus generator output available reached the level where it was possible to start employing it in unconventional ways.  The VF-25, for instance, employed that additional surplus to improve its defensive abilities still further with a newfound ability to run its energy conversion armor around vital areas at low power in Fighter mode.  The VF-27 used the surplus power from its four engines to drive a massive beam machine gun with firepower rivaling or exceeding that of the current-generation anti-Vajra rotary cannon used by the VF-25.  Later models like the VF-31 seem to have just adjusted their engine tunings to prioritize generator output over thrust and enabled the use of a smaller, less powerful beam gunpods that nevertheless at least rivals what more conventional gunpods can do.  Even then, they still keep hard round cannons around as a backup just in case.  

Aside from being simpler, cheaper, and more resistant to EMPs, conventional (OTM-improved) hard round cannons have a distinct advantage over beam gunpods in terms of the energy requirement.  They can operate without a supply of power from the VF's reactors, since they have an internal battery they can use to drive the cannon's motor and firing is chemical combustion so there's no power requirement there either.  Beam gunpods can be made as small as a conventional gunpod, but ultimately it's just an externally carried beam cannon powered by the VF's reactors and if the reactor is compromised the beam gunpod is worthless.  There's no onboard power supply for the beam gunpod.  The two-engine YF-27 prototypes needed to carry an external wing-mounted reactor module to drive their beam gunpods because they lacked the power to do so on just their two main engines.  The advantage to a beam gunpod, of course, is that they have effectively unlimited ammunition as long as the reactors are running and supplying power and the gun's cooling system can keep up, and theoretically there is no cap on their firepower the way there is for the chemical propellants of the conventional gunpods.  We've also seen that beam gunpods can potentially be improved further from particle beam weapons to dimensional weapons with sufficient power.