STOVL UCAV (STOCAV)
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| Lockheed Martin VARIOUS |
Introduction
Armed UAVs and loitering munitions play an increasing role in warfare. UAVs are typically classified into five Groups, by size range.
Fixed-wing UAVs above Group 3 usually require a runway. This limits their ability to generate sorties when their operating area is not in close proximity to the airfield. Transit to and from the airfield is a significant factor in the overall sortie time.
Rotary-wing aircraft like the MQ-8C Fire Scout or smaller UAVs like STUAS can sortie from areas closer to their operating area and return to Forward Arming and Refueling Points (FARPs), to shorten their turn around times between sorties. However, they are vulnerable to all manner of air defenses and don't carry very much.
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| MQ-8C Fire Scout |
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| STUAS |
UAV-based Armed ISR and Close Air Support requires larger, fixed-wing UAVs like the Army's MQ-1C Grey Eagle and USAF's MQ-9 Reaper, but they need a long runway.
What's needed is a Group 4, armed UAV that can operate from unprepared areas and FARPs, and move with ground forces.
Potential missions could include,
- ISR/Maritime ISR
- CAS/Interdiction
- SEAD/DEAD
- ASuW
- ASW Support
- Counter-UAV
While not a true long-endurance UAV, the STOCAV can operate forward, closer to the action. This reduces transit times to and from its base, allowing it to spend more time on station.
Ideally, the FARP will be located approximately 17 to 25 kilometers from the FEBA or FLOT. This positioning ensures it is far enough to the rear to prevent enemy artillery preparatory fires from targeting the FARP, yet allows the quick turnaround of aircraft and logistical transportation supporting the operation.
Assuming the FARP is 25km back, and the STOCAVs operates 25km ahead of FEBA/FLOT, they have a round trip of 50km. A STOCAV flying at 550 km/h (~300kts) can cover the distance back to the FARP in under 10 minutes. Assuming it has two hours on station per sortie at this distance, 20 minutes for travel to and from, and another 20 minutes to refuel and rearm at the FARP, it could be on station 2/3rds of the time. So while it may not have the endurance of a MALE UAV like Grey Eagle, it can approximate it with repeated sorties to and from a FARP.
Given the relatively small size and weight of STOCAV, FARP refueling seems far more feasible than with a 50,00lb F-35B and its voracious F135 engine. A 500 gallon collapsible fuel drum might refill one or two STOCAVs. On the other hand, FOUR 500 gallon drums are needed to refill a single F-35B.
Design
Of the many Group 4 armed UAV concepts, Lockheed Martin VARIOUS is the closest to the STOCAV concept.
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| Lockheed Martin VARIOUS |
It is jet-powered and uses a twin lift-fan arrangement for STOL/STOVL.
Lockheed Martin VARIOUS General Characteristics:
Gross Vehicle Weight: 6,000-8,000lb
Wingspan: 28.5 ft
Length: 22 ft
Max Speed: 360kts
Payload: ~450lbs internally, up to 1,900lbs total
Sensors: EO/IR/Laser, perhaps a small radar with CUAV air-to-air engagement modes
This puts it between the size of the MQ-1C Grey Eagle and the MQ-9 Reaper. It wouldn't have anywhere close to their endurance, but as shown above, it would make up for it by being able to quickly cycle back to FARPs.
Armament
The VARIOUS literature shows it carrying a pair of Hellfires internally, but this seems very limiting. I think stretching the bomb bay to carry a single GBU-54, 500lb Laser JDAM opens up a lot of possibilities.
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| GBU-54 |
First, this size weapon is not typically available to ground forces without calling in fixed-wing airpower or ATACMS unitary. Second, the 500lb class Mk82 warhead is a useful size to knocking out buildings and other field fortifications that are too large or too strong for traditional artillery.
Third, a bomb bay that can accommodate a ~2.3m long weapon opens the possibility of carrying the 500lb CBU-78 ICM/GATOR mine dispenser, or multiple smaller weapons.
Some likely smaller weapons include a pair of SDB/SDB IIs, or up to six or more, sixty pound, GBU-69/B Small Glide Munitions.
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| GBU-69/B Small Glide Munition |
An anti-armor variant could be developed with a tandem HEAT warhead.
Even further down the line, smaller glide bombs carried in larger numbers, such as the Raytheon Pyros or Lockheed Martin Hatchet make a lot of sense.
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| By Mztourist - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=56735933 |
Pyros is a 90mm diameter, 55cm long, 13lb bomb, with a 5lb warhead and SALH/GPS/INS guidance. Up to sixteen of these could be carried STOCAVs main bay, assuming single stacking. If a bomb rack could be built that could stack them, up to 64 could be carried, though that would be rather heavy for STOCAV.
Some may discount the value of such small weapons, but the Azerbaijani's made good use of a similar munition (MAM) on their Turkish TB2 UAVs, striking individual Armenian fighting positions in the recent conflict.
The STOCAV could also add a small pylon on each bay door to carry a light-weight A2A weapon. Possibilities include A2A Stinger, or mini-AAMs like the 6-foot long, 150lb, Raytheon Peregrine, or Miniature Hit To Kill (MHTK) missile, or the Air Force Research Lab's Miniature Self-Defense Munition (MSDM).
STOCAV isn't meant to go up against manned fighters, but the future battlefield will be swarming with UAVs of all sizes and Counter-UAV is one of STOCAVs missions.
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| Air to Air Stinger Twin Mount |
Survivability
STOCAV would be designed with stealth in mind. It doesn't have to be high-end, broadband stealth, but should geared towards the bands and radars commonly found in SHORADS/VSHORADS operating with forward forces. A prime example is the Russian Panstir S1 system. An RCS equivalent to 0.01m2 (-20 dBsm) over most aspects would allow STOCAV to approach within around 10km before being detected.
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| http://www.ausairpower.net/APA-Engagement-Fire-Control.html#mozTocId853844 |
This is well within SGM or SDB range.
Conclusion
STOCAV could take the load off of airfield-based, fixed-wing airpower, both manned and unmanned, and provide more force resilience through distributed operations and base mobility. The advent of inexpensive, small guided munitions, carried in large numbers, allows STOCAV to prosecute numerous targets per sortie. It's speed and STOVL capability allows STOCAV to generate numerous sorties per day, during high intensity operations, offsetting its modest payload and endurance. STOCAVs speed also permits overmatch against traditional UAVs in worldwide service, allowing it to attack them with air-to-air missiles before they threaten friendly forces.
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