Author Topic: Bodyguard Fixed Wing  (Read 521 times)

Lagrange

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Bodyguard Fixed Wing
« on: 14 August 2024, 21:24:26 »
The Bodyguard is something like a conventional fighter, except that it's able to stay airborne indefinitely, since no fuel is required and the pilot is off board. 

The Bodyguard is inevitably slow given that it's a fixed wing prop design.  Nevertheless, fixed wings can move to atmospheric row 1 and move around with a velocity of 1 (~= 1000km/hour) allowing them to use the indefinite range well. 

The Bodyguard lacks the armor, speed, and firepower of a dedicated aerospace fighter.  They make up for this considerably on an economic basis.  For example, a dedicated heavy space superiority fighter might cost 6M, equivalent to 20 Bodyguards.  The 20 Bodyguards have a total of 20 tons of armor and 400(!) LRM tubes, making them quite dangerous in massed formations of equivalent cost.

The interesting element of the Bodyguard is it's ability to loiter indefinitely in the air, fulfilling a class of missions which can't be fulfilled otherwise.
  • LZ Halo:  Bodyguard are launched by a descending drop ship and hover over a landing zone, firing en masse against any enemy ASF that tries for a bombing run.
  • Bomber escort: An invading dropship comes down over the ocean, launch swarms of Bodyguard and Mayfly then takes off back into space to remote pilot an invasion force where the Mayfly swarm wipes out ground forces and the Bodyguard swarm protects the Mayfly swarm.
  • Raid defense: Around a capitol city, a Bodyguard swarm is kept aloft providing security for the spaceport and a near-instantaneous response to any ASF raid.
The Bodyguard is also designed for (ultra-lethal) aerial combat since if a control roll is failed the cost is minor and the pilot is never killed.

Code: [Select]
Bodyguard Fixed Wing

Mass: 17.5 tons
Frame: Unknown
Power Plant:  Fusion
Armor: BAR 7
Armament:
     4 LRM 5
Manufacturer: Unknown
     Primary Factory: Unknown
Communication System: Unknown
Targeting & Tracking System: Unknown
Introduction Year: 2455
Tech Rating/Availability: C/E-F-F-X
Cost: 298,772 C-bills

Type: Rover
Technology Base: Inner Sphere (Advanced)
Tonnage: 17.5
Battle Value: 133

Equipment                                          Mass
Engine                         Fusion                 4
Safe Thrust: 3
Max Thrust: 5
Structural Integrity:         3                       
Heat Sinks:                   0                       0
Fuel:                         0                     0.0
Cockpit                                               2
Armor Factor (BAR 7)          21                      1

                           Armor   
                           Value   
     Nose                    7     
     Wings                  5/5   
     Aft                     4     


Weapons
and Ammo                 Location   Tonnage  Heat   SRV  MRV  LRV  ERV
4 LRM 5                    NOS       8.0      2      3    3    3    0 
LRM 5 Ammo (24)            BOD       1.0      -      -    -    -    - 
Drone Operating System     BOD       2.25     -      -    -    -    - 
SV Chassis Mod (Propellor) BOD       0.0      -      -    -    -    - 

Features the following design quirks: Atmospheric Flyer, No Ejection System

Why LRMs?  It's a slow unit so it has to have range to avoid being sniped. The LRM-5 is cheap ranged choice in a 3025 context.

One of the key questions here is right-sizing.  Should it be 1, 2, 4, or more LRM-5s?  I decided to go with 4 because that amortizes overheads reasonably well.

Ammo is also a concern.  Although 1 ton is light compared to what you might think of, I expect this is typically enough since the damage potential is beyond 3x the armor on the Bodyguard.  By accepting that this is not a long duration fighter, we save a ton and ~15% off the price.

Lagrange

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Re: Bodyguard Fixed Wing
« Reply #1 on: 21 August 2024, 11:57:19 »
I've been debating this one in my head.   The loiter time of the Bodyguard is quite nice, but it comes with the significant disadvantages of fragility, low speed, and losing initiative vs. ASF.   Judging the combat value against a custom 3025 ASF, 15-1 might be a reasonable ratio without fully taking into account losing initiative.  That's significantly worse on a per-ton basis and only marginally better on a per cost basis.  Hence, it's only justifiable if there isn't an alternative way to fulfill the same missions.

It's tempting to try to substitute VTOL for Bodyguard, but that doesn't work in general since VTOLs use ground unit ranges while aerospace units use aerospace ranges (measured in map sheets) for weapons.  Airships are not an alternative either---they are even more fragile and they can't visit the high altitude map.

Thus the question is: can we avoid long-loiter designs in the missions?

LZ Halo:  ASF could take off from altitude 0 and fairly easily reach the high altitude map in 1 minute or less.  For example, a slow 3/5 aerodyne could:
Round 1: Takeoff -> Altitude 1, velocity 5
Round 2: Ascend 2, +1 velocity -> Altitude 3, velocity 3
Round 3: Ascend 2, +1 velocity -> Altitude 5, velocity 2
Round 4: Ascend 2, +1 velocity -> Altitude 7, velocity 2
Round 5: Ascend 2, +1 velocity -> Altitude 9, velocity 2
Round 6: Ascend 2, +1 velocity -> Altitude 11, velocity 2
Appear on the high altitude map.

Since there are 6 ground turns per high altitude turn, that's just a 1 turn delay in getting there.

The Raid Defense mission has a similar effective response, which leaves just the Bomber Escort mission to worry about.  Since Fixed-Wing bombers can use the high altitude map at velocity 1, they can move about 1000km/hour.  A 3 ton fuel tank puts the limit of a fueled escort at 4 hours implying a 2000 kilometer bombing range would be allowed (or more, with fuel tanks).  That's probably enough for bomber escort missions.

If we use a fueled alternative foe bombing escort, the lethality of the mission is important.  Atmospheric control rolls fail ~28% of the time.  On the high altitude map, this does not really matter: worst case you enter the low altitude map and given that there are 6 ground rounds you can easily recover in time to avoid missing a high altitude round.  On the low altitude map, you lose 1d6 altitudes though meaning an expected ~1 altitude per round that damage is taken.  If the bomber escorts operate from altitude 10 or so by default that leaves them with quite a bit of opportunity to recover---they would have to fail a control roll 3 rounds in a row on average which is ~2% chance.  If each control roll comes with 5 points of damage, that implies an expected ~250 damage before a fighter attempting to stay at altitude 10 is forced to impact the ground. 

Given the above, it seems an ASF escort is plausibly a better choice than a conventional fighter, and it could even be a relatively heavy one.

 

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