Unmanned Aerial Logistics Vehicles— A Concept Worth Pursuing ?


Senior Member
Feb 23, 2009
This thread is intentioned for a specific discussion within the context of the US of A's 'War on Terror' in Afghanistan. Parameters to ponder with respect to are:

  • [*]Load and capacity
    [*]Cost and Viability
    [*]Geo-strategic and foreign policy
    [*]Risks and Versatility
Feel free to input with respect to any other context however if you see the need.


Unmanned Aerial Logistics Vehicles—A Concept Worth Pursuing [?]*

by Major John V. McCoy

Predator makes its way back to the hangar at a forward base
after flying a reconnaissance mission over Afghanistan

Military history is rich with scenarios in which ground convoy routes have been interdicted by enemy activity and closed until the threat was cleared. Using unmanned aerial vehicles (UAVs) to make deliveries in such scenarios would allow logistics units to solve the tactical dilemma of providing food, medical supplies, critical parts, or ammunition when the risk to ground logistics assets is high.

UAVs may help to meet logistics needs on future battlefields, yielding the benefits of simplicity, reliability, flexibility, lift capability, interoperability, asset visibility, reduced risk, and lower cost. The benefits of using unmanned resupply aircraft may exceed those of relying on manned ground resupply systems and existing air resupply systems such as C–130, C–17, and C–5 transports and UH–60 and CH–47 helicopters. UAVs have the potential to reduce the risk to human life in combat operations, reduce the logistics footprint in theaters of operations, and improve logistics effectiveness and efficiency.

The types of UAVs that could be used include helicopters, fixed-wing aircraft, and blimps. Each could be used in conjunction with navigation-guided parachute systems. Existing small, unmanned helicopters, airplanes, and blimps have enough cargo capacity to each deliver a cargo of 13 cases of meals, ready to eat (MREs), which together include 156 meals, weigh 221 pounds, and occupy 10.8 cubic feet of space. Unmanned aircraft, such as a blimp, may carry larger payloads up to 160 tons.

Possible UAV Delivery Methods

Four methods could be used with UAVs to deliver supplies—

• UAV loads, takes off, lands, and unloads.
• UAV loads, takes off, airdrops, and returns.
• Heavy-lift blimp loads, takes off, and hovers; smaller UAVs deploy and land.
• Heavy-lift blimp loads, takes off, and hovers: smaller UAVs airdrop and return.

Each method has advantages and disadvantages that must be considered when determining its use.

Raytheon Killer-Bee UAV
Raytheon says the militarized KillerBee
has more room for payloads and more
than 100 miles of range, plus the ability
to track objects day or night with video
and infrared feeds, and guide precision
munitions with an on-board laser designator

UAV Loads, Takes Off, Lands, and Unloads

This process involves loading a UAV with supplies at a source takeoff site. The UAV then flies to a landing area near the customer and lands. After being offloaded, the aircraft takes off and returns to its point of origin or another source of supply, perhaps backhauling cargo if necessary. All three types of UAVs have the technology needed to take off, carry cargo, and land at a delivery site.

This process stands out as the simplest UAV delivery method because it involves fewer system components than other possible processes. The process involves only the UAV and the cargo. Its simplicity also creates a minimum logistics footprint; no footprint is required for rigging support, large amounts of cargo, or multiple vehicles. This process also provides commanders with the least complicated scenario for controlling airspace. A single delivery involves only one route of flight for one vehicle, with no requirements to deconflict airspace in order to accommodate multiple vehicles or multiple airdrop loads. The process can deliver less than a truckload without committing a truck’s worth of lift. Current ground transport resupply methods require the dispatch of vehicles capable of hauling over a ton, even if the required cargo weighs only 200 pounds.

Because the UAV requires a runway to land, the load, take off, land, and unload process cannot be used in undeveloped areas. The time required to load cargo and identify a suitable destination runway also would make the use of the UAV to quickly fill unforeseen requirements impractical, especially for multicustomer deliveries.

UAV Loads, Takes Off, Airdrops, and Returns

In this process, a UAV is loaded with supplies at a source takeoff site. The aircraft then flies over its customers, airdrops its supplies, and returns empty to the source takeoff site for another mission.

A UAV can conduct an airdrop and return to its airfield of origin. No insurmountable aerodynamic control problems are associated with cargo loads ejected from the aircraft while it is in flight, and it is possible to control the ejection of airdrop cargo from distant ground-based control stations. A lightweight precision airdrop system can guide an airdrop load as small as 200 pounds to within 100 meters of its designated landing location from an aerial release point 20 kilometers away. Cargo aircraft used to discharge multiple lightweight precision airdrop bundles can be equipped with automated takeoff, flight, and landing capabilities.

This process is relatively simple when compared to hover-and-deliver systems with their multiple vehicles and multipart systems, but not as simple as the take-off-and-land process. The take-off-and-airdrop process involves a relatively reduced footprint. No additional space- besides for rigging and maintenance- is required to support multiple aircraft or multiple airdrop rigging systems. The process has the advantage of being able to make deliveries when no landing area is available in the vicinity.

This process can service multiple customers by flying in a circuit route and dispatching airdrop loads to customer after customer. Airdrop requires more airspace control than does the process that does not involve airdrop. Because multiple items of equipment may pass through multiple air corridors, additional coordination with other military airspace users is needed.

The greatest disadvantage of this process is the reduction in lift capacity due to the additional weight of the precision airdrop equipment.

The concept of using a heavy-lift blimp to launch smaller UAVs has a historical
basis. In 1933, the Navy used dirigibles as airborne aircraft carriers.

Above, the USS Macon retrieves two Curtiss F9C–2 airplanes.

Curtiss F9C–2 Sparrowhawk attaches to the trapeze of the USS Macon

Blimp Hovers; Smaller UAVs Deploy and Land

This process involves loading a heavy-lift blimp with smaller UAVs that, in turn, are loaded with supplies. The blimp then takes off and stations itself in a position in the air to wait for supply requests or orders. As orders are received, the heavy-lift airship deploys the UAVs carrying supplies. The UAVs land near their customers, and supplies are offloaded.

Blimps can be constructed to airlift up to 160 tons in a cargo area 50 meters by 8 meters by 8 meters. They can be controlled from ground stations through takeoff, flight, and landing. Because of the additional cargo capacity that blimps can provide, UAVs operating from them could be used for ammunition resupply. Parafoil airdrop systems can deliver loads weighing up to 21 tons from aerial platforms to target areas on the ground using a glide ratio of 3 to 1. (A glide ratio of 3 to 1 enables supplies to be sent to the ground out to distances three times the altitude of the aerial platform at the time of airdrop cargo release.)

The heavy-lift blimp provides increased responsiveness when compared to ground-based processes. By having supplies in the air all the time as part of this process, no additional time is needed to load cargo in response to a sudden, unexpected request.

The use of blimps and UAVs is expected to provide the same benefits of reduced risk to delivery personnel when compared to manned systems, the same opportunities for interoperability, and the same level of asset visibility as the other processes considered. This process also enables logistics resupply as efficient as that provided by other manned and unmanned aerial supply methods for a noncontiguous operation.

However, despite providing relative increases in responsiveness, this process does not perform as well as the other processes. The use of blimps and UAVs likely would be chosen only if assets of the other processes were fully committed and this process was used to supplement their capabilities.

This system rates worse than simpler take-off-and-land and take-off-and-airdrop systems in reliability, footprint, and personnel required. The requirement for multiple vehicles in this process complicates airspace control more than processes using a single vehicle, and the requirement for destination airfields limits the flexibility of this process to respond to unforeseen requirements.

Blimp Hovers; Smaller UAVs Airdrop and Return

This process involves loading a heavy-lift blimp with smaller UAVs carrying supplies. The blimp takes off and stations itself in a position in the air to await supply requests or orders. As orders are received, the blimp deploys the smaller UAVs, which then fly over their customers airdropping supplies. The UAVs then return empty to the blimp for future use.

Blimps can launch and recover smaller aircraft. Smaller UAVs could be constructed to depart from blimps, fly to designated release points, and discharge precision airdrop loads to customers on the ground. Those same UAVs could return, be hoisted inside the blimp’s cargo area, and be reloaded automatically by mechanical systems that deposit additional cargo into each UAV’s cargo bay.

This process would provide the tactical advantage of extending the distance from danger at which UAVs (in this case, unmanned supply blimps) could hover. Advantages gained by increasing the distance from air threats would enhance the survivability of the blimps.

This process is the best when considered against the criteria of responsiveness and flexibility. Supplies in the air would not require time to load, taxi, and take off, so the customer wait time when responding to unexpected supply requests would be reduced. Without the need for landing zones near unexpected customers, the customer wait time would be reduced. Customers far from suitable vehicle landing sites could be supplied by airdrop. This process is the most responsive and flexible of all the UAV supply processes considered.

This process also is the best for supporting multiple customers. A single system could serve customers at many aerial release points as multiple delivery vehicles dispatch multiple airdrop loads. No other system has such a widespread simultaneous delivery capability.

This process is expected to provide the same benefits of reduced risk to delivery personnel when compared to manned systems, the same opportunities for interoperability, and the same level of asset visibility as the other processes considered. This process also enables logistics resupply in a noncontiguous operation that cannot be supported by ground lines of communication.

This process also has disadvantages. It requires the most personnel and the biggest footprint and is the most complicated. It presents the most difficult airspace management scenario and is likely to be the least reliable. Personnel would be required to maintain the heavy-lift and delivery vehicles, the automated loading system, and the airdrop equipment. Space would be required for the heavy-lift vehicle, the delivery vehicles, the controllers, and the rigging areas. The various airspaces required by the heavy-lift vehicle, the delivery vehicles, and the airdrop cargo itself all require deconfliction with other airspace users. The requirement of this process for complicated airborne launch and recovery of delivery vehicles and for multiple airdrop systems reduces the process reliability.

rotary-wing aircraft
conducts a slingload

Potential Systems Versus Existing Systems

The delivery of meals, ready to eat (MREs), provides a good subject for a comparison of the different modes of delivery since virtually all Army consumers of supplies on the battlefield require resupply of MREs at some point. Current modes of MRE distribution to be considered in the comparison include cargo truck, helicopter slingload, watercraft, fixed-wing airdrop, and fixed-wing air land.

Cargo truck delivery—the most prevalent resupply system used by the Army—involves loading cases of MREs into the cargo area of a truck that subsequently travels by road to the customer. Helicopter slingload involves strapping cases of MREs into a cargo sling that hangs from a hook on the bottom of a helicopter as it flies from the supply pickup point to the delivery point. In watercraft delivery, cases of MREs are loaded onto lighters, flat-bottomed boats, or barges and transported from port to port. For fixed-wing airdrop, airplanes are loaded with pallets of MREs rigged for airdrop, the airplanes are flown to a release point above a customer, and the cargo is released to travel by parachute to the customer on the ground. In fixed-wing air land, cases of MREs are loaded onto fixed-wing aircraft, the airplanes are flown to a destination airstrip and landed, and the MREs are discharged from the aircraft.

The modes of supply delivery can be compared using the following categories: risk of loss of life, response time, versatility, suitability, less-than-truckload supply operations, and complexity.

Risk of loss of life. The mode presenting the greatest risk to life is truck transport because its manned systems are restricted to moving along linear lines of march. Watercraft deliveries also risk loss of life because watercraft are restricted to the surface of the water, where their operators are vulnerable to surface threats, mines, and enemy watercraft. Helicopter slingload and fixed-wing air land each involve risks to life, though to a lesser extent than do watercraft and truck distribution. Flight paths are impossible to mine, and aircraft follow less predictable routes. However, the need to land on the ground to discharge their loads increases their vulnerability. Fixed-wing airdrop involves the least risk to life of any of the manned modes because the aircraft do not need to land in customer areas.

All four of the potential UAV solutions offer less risk to life because no humans are employed along the route between the source of supply and the customer.

Response time. UAVs equal or exceed the best performances of the best existing modes of delivery. The most responsive of the existing modes is airdrop because the aircraft used to conduct airdrop travel very fast and require no cargo offload time. Fixed-wing air land is the next most responsive mode, because it travels at the fastest speeds and the cargo can be offloaded quickly at the destination airstrip. Helicopter slingload ranks third, and trucks fourth. Watercraft rate the slowest in response time because they move at speeds that peak at around 12 knots—only 13 miles per hour.

UAVs are equal to, and in some cases are much better than, existing modes of delivery when considering response time. If one were trying to reduce risks to life, using UAVs would do so without increasing response time.

second DarkStar
unmanned aerial vehicle successfully
completed its first flight after taking off
from the Air Force Flight Test Center
at Edwards Air Force Base,

Versatility. Delivery by UAV equals the more versatile existing mode of MRE delivery. The more restricted of the existing modes are watercraft and trucks because they are confined to certain surfaces. The more versatile delivery modes are helicopter slingload, fixed-wing air land, airdrop, and the proposed UAV operations. These modes can deliver over both water and land.

Suitability. For noncontiguous operations, the capabilities of UAVs are equal to or better than those of existing modes of distribution. When the customer is operating in enemy territory or the enemy has cut off all ground lines of communication to the customer, watercraft and trucks cannot make the deliveries. In such cases, air modes of resupply must be used, and the UAV concept provides the same capabilities as existing air modes without risking loss of life. The UAV concept is particularly well suited for noncontiguous operations because it can make deliveries without the risk to life that all manned operations have.

Less-than-truckload supply operations. The UAV concept is the most efficient possibility for the delivery of quantities of supplies that will not fill a truck. If a few cases of MREs were needed on the battlefield, small UAVs would be the best possible means of delivery. The use of existing fixed-wing aircraft to deliver three cases of MREs would waste the airplane’s remaining cargo space. Using a helicopter, watercraft, or truck to deliver such a small quantity also would commit an entire large asset and waste its unused cargo space. However, a UAV with a small cargo-carrying capacity could be developed to meet the requirement without wasting cargo capacity. Trucks then could be saved for carrying full truckloads. Small loads requiring delivery could include small repair parts, software, or medicines and other lifesaving medical supplies.

Complexity. UAVs are among the most complex of the delivery modes, while the least complex mode is the truck. UAV take-off-and-landing and take-off-and-airdrop processes are less complex than those of their manned air counterparts because they do not need subsystems for cockpit operations. Reduced complexity typically translates into greater reliability and reduced costs, both preferred characteristics.

To reap the less-risk-to-life and responsiveness benefits associated with the more complex UAV systems, there is a tradeoff in greater complexity, lower reliability, and higher cost. However, to reap the lower risk-to-life benefits associated with the less complex UAVs, no tradeoff in complexity need be made. In fact, in these cases, added benefits of reduced complexity and cost may be gained when compared to existing manned rotary-wing and fixed-wing systems.

The Army should develop and implement the unmanned aerial logistics vehicle concept. Once the concept is proven in principle, the responsiveness, precision, and supply capabilities of unmanned aerial logistics vehicles will lead Army unit supply customers to determine additional applications. Military UAVs are useful today, particularly in the areas of reconnaissance and ordnance delivery. Innovation should expand the role of military UAVs to the arena of logistics resupply.

Unmanned Aerial Logistics Vehicles—A Concept Worth Pursuing

* emphasis added

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