Piper J-3 Cub and Cousins

[Giovanni Blasini]

Yes, I am a madman.  It is well-known.  I've also spent a lot of time in Flight Simulator X Steam Edition lately.

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Piper Cub J-3

Mass: 0.6 tons
Frame: Unknown
Power Plant:  ICE
Cruising Speed: 10.8 kph
Maximum Speed: 21.6 kph
Armor: BAR 2
Armament:
Manufacturer: Unknown
     Primary Factory: Unknown
Communication System: Unknown
Targeting & Tracking System: Unknown
Introduction Year: 1950
Tech Rating/Availability: D/C-E-D-X
Cost: 502 C-bills

Type: Piper Cub
Technology Base: Inner Sphere (Standard)
Tonnage: 0.6
Battle Value: 11

Equipment                                          Mass
Engine                         ICE                0.045
Safe Thrust: 1
Max Thrust: 2
Structural Integrity:         0                       
Heat Sinks:                   0                       0
Fuel:                         10                   0.23
Cockpit                                               0
Armor Factor (BAR 2)          4                     0.1

                           Armor   
                           Value   
     Nose                    1     
     Wings                  1/1   
     Aft                     1     


Weapons
and Ammo              Location   Tonnage  Heat   SRV  MRV  LRV  ERV
SV Chassis Mod          BOD       0.0      -      -    -    -    - 
SV Chassis Mod          BOD       0.0      -      -    -    -    - 
SV Chassis Mod          BOD       0.0      -      -    -    -    - 


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Piper Cub L-4 Grasshopper variant

Mass: 0.6 tons
Frame: Unknown
Power Plant:  ICE
Cruising Speed: 10.8 kph
Maximum Speed: 21.6 kph
Armor: BAR 2
Armament:
     1 Recoilless Rifle (Light) - Inferno
Manufacturer: Unknown
     Primary Factory: Unknown
Communication System: Unknown
Targeting & Tracking System: Unknown
Introduction Year: 1945
Tech Rating/Availability: D/X-X-X-X
Cost: 805 C-bills

Type: Piper Cub
Technology Base: Inner Sphere (Standard)
Tonnage: 0.6
Battle Value: 12

Equipment                                          Mass
Engine                         ICE                0.045
Safe Thrust: 1
Max Thrust: 2
Structural Integrity:         0                       
Heat Sinks:                   0                       0
Fuel:                         10                   0.23
Cockpit                                               0
Armor Factor (BAR 2)          4                     0.1

                           Armor   
                           Value   
     Nose                    1     
     Wings                  1/1   
     Aft                     1     


Weapons
and Ammo                     Location   Tonnage  Heat   SRV  MRV  LRV  ERV
Recoilless Rifle - Inferno     NOS      0.008     0      0    0    0    0 
SV Chassis Mod                 BOD       0.0      -      -    -    -    - 
SV Chassis Mod                 BOD       0.0      -      -    -    -    - 
SV Chassis Mod                 BOD       0.0      -      -    -    -    - 

Notably, there are a number of designs that are basically 3/4 scale J-3 Cubs that meet FAR 103 guidelines as ultralights, ie. being under 254 lbs empty, 5 gallon fuel limit, etc. but trying to recreate one exactly under support vehicle rules caused issues due to fuel mass.  On the other hand, making it electric, while making MegaMekLab unhappy ("Aerospace units must allocate some weight for fuel."), the actual rules for a solar prop-powered support vee solves the fuel issue by eliminating it:

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Electric Cub J-103

Mass: 0.115 tons
Frame: Unknown
Power Plant:  Solar
Cruising Speed: 10.8 kph
Maximum Speed: 21.6 kph
Armor: BAR 2
Armament:
Manufacturer: Unknown
     Primary Factory: Unknown
Communication System: Unknown
Targeting & Tracking System: Unknown
Introduction Year: 2015
Tech Rating/Availability: D/C-E-D-X
Cost: 359 C-bills

Type: Electric Cub
Technology Base: Inner Sphere (Standard)
Tonnage: 0.115
Battle Value: 11

Equipment                                          Mass
Engine                         Solar              0.015
Safe Thrust: 1
Max Thrust: 2
Structural Integrity:         0                       
Heat Sinks:                   0                       0
Fuel:                         0                     0.0
Cockpit                                               0
Armor Factor (BAR 2)          4                     0.1

                           Armor   
                           Value   
     Nose                    1     
     Wings                  1/1   
     Aft                     1     


Weapons
and Ammo              Location   Tonnage  Heat   SRV  MRV  LRV  ERV
SV Chassis Mod          BOD       0.0      -      -    -    -    - 
SV Chassis Mod          BOD       0.0      -      -    -    -    - 
SV Chassis Mod          BOD       0.0      -      -    -    -    - 

Obviously, these can be used for other similar aircraft as well, either as is, or with some tweaks.  For example, here's a Cessna 162:

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Cessna Skycatcher C162

Mass: 0.6 tons
Frame: Unknown
Power Plant:  ICE
Cruising Speed: 21.6 kph
Maximum Speed: 32.4 kph
Armor: BAR 2
Armament:
Manufacturer: Unknown
     Primary Factory: Unknown
Communication System: Unknown
Targeting & Tracking System: Unknown
Introduction Year: 2006
Tech Rating/Availability: D/C-E-D-X
Cost: 654 C-bills

Type: Cessna Skycatcher
Technology Base: Inner Sphere (Standard)
Tonnage: 0.6
Battle Value: 13

Equipment                                          Mass
Engine                         ICE                0.048
Safe Thrust: 2
Max Thrust: 3
Structural Integrity:         1                       
Heat Sinks:                   0                       0
Fuel:                         16                  0.288
Cockpit                                               0
Armor Factor (BAR 2)          4                     0.1

                           Armor   
                           Value   
     Nose                    1     
     Wings                  1/1   
     Aft                     1     


Weapons
and Ammo              Location   Tonnage  Heat   SRV  MRV  LRV  ERV
SV Chassis Mod          BOD       0.0      -      -    -    -    - 
SV Chassis Mod          BOD       0.0      -      -    -    -    - 
SV Chassis Mod          BOD       0.0      -      -    -    -    - 



[Daryk]

Is ~20 kph fast enough to actually get airborne? 

I think humans can run faster than that...

[Giovanni Blasini]

Is ~20 kph fast enough to actually get airborne? 

I think humans can run faster than that...

Yeah, that figure is just MegaMekLab goofiness.  These are 1/2 thrust aerospace craft that are propeller-powered.  Being propeller-powered taps out the maximum speed they can travel at.  Admittedly, 1/2 thrust is imprecise, but we'd probably need to get into fractional thrust accounting, and let's just not go there.

Rules as written require a safe thrust of 2 to take off, but I'd argue that's excessive for these.  On the low altitude map, each hex/turn works out to 500 meters/turn or 50 m/s.  That's 180 kph, or 97 kn.  A Piper J-3 has a cruising speed of 65 kn, and 76 kn max speed.  The Cessna 162 is faster with a 112 kn cruse speed and 118 kn max speed.

In the end, I decided on 1/2 thrust for these to basically duplicate what was done in XTRO 1945, assigning 1 thrust point per 100 mph of speed, more or less.  It's not perfect, requires some kludging, but it's the same kind of kludging that everything in XTRO 1945 uses, which isn't surprising, given the J-3 and L-4 are also from that era.

[Daryk]

Makes sense, thanks!