Classification According to Size

A common and intuitive approach classifies UAS by physical size. While boundaries vary by source, size is often correlated with payload capability, endurance, launch/recovery infrastructure, and typical mission scope.

Very Small UASs

Very small unmanned aerial vehicles (UASs) encompass platforms ranging from insect-sized constructions up to those measuring approximately 30 to 50 centimeters in length. These UASs are exceptionally lightweight, making them suitable for operations over limited distances. Their compact size allows for diverse design approaches, including flapping-wing mechanisms, rotary-wing structures, and miniature fixed-wing configurations. Flapping-wing UASs excel in maneuverability, enabling them to perform agile movements and even perch or land on restricted surfaces. Rotary-wing variants stand out for their ability to hover steadily, which is especially useful in confined environments or for tasks requiring stationary flight.

Notable examples of very small UASs, Figure 1, include the IAI Malat Mosquito, which features a wingspan of roughly 35 centimeters and can remain airborne for about 40 minutes. Another representative is the Aurora Flight Sciences Skate, with a wingspan close to 60 centimeters and a length of approximately 33 centimeters. Additionally, the Cyber Technology CyberQuad Mini, with its square 42 by 42-centimeter footprint, and the larger CyberQuad Maxi, illustrate the variety in this UAS class. These systems highlight the technological advancements and versatility found within the very small UAS category.

 

hand drawn sketch of the Mosquito, Skate, and CyberQuad Mini UASs.
Figure 1 Examples of very small UASs (Source: Paul Fahlstrom and Thomas Gleason, 2012, Introduction to UAS Systems, 4th edition, Wiley)
Paul Fahlstrom and Thomas Gleason, 2012, Introduction to UAV Systems, 4th edition, Wiley

 

Small UASs (Mini-UASs)

Small UASs (often called mini-UASs), Figure 2, typically include platforms with at least one dimension > 50 cm and up to ~2 m. Many are fixed-wing systems and are commonly hand-launched, enabling rapid field deployment without runway infrastructure. Rotary-wing designs are also present in this class, particularly for hovering and confined-area operations.

Representative examples (illustrative):

  • RQ-11 Raven (approx. 1 m length; ~1.4 m wingspan).
  • Bayraktar mini class systems (approx. 5 kg; data link range ~20 km), Figure 5.
  • RQ-7 Shadow, Figure 3.
  • AiRanger™ (crossover system spanning small to medium characteristics), Figure 4.

 

person running through a field holding a small UAS above their head.
Figure 2 Hand-launched small UAS (Source: Woolpert, Inc. woolpert.com)
"Woolpert, Inc. woolpert.com"

 

Small white UAS flying through the air
Figure 3 A US army RQ-7 Shadow. The RQ-7B, or the Shadow 200, is the type of unmanned aerial vehicle flown by VMU-3. (Source: RQ-7B by US Marines USMC (Public Domain))
RQ-7B by US Marines USMC (Public Domain)

 

gray UAS
Figure 4 The AiRanger™
American Aerospace

 

Scetch of Brayraktar and Raven B UASs
Figure 5 Examples of small UASs
Paul Fahlstrom and Thomas Gleason, 2012, Introduction to UAS Systems, 4th edition, Wiley

Medium UASs

Medium unmanned aerial vehicles (UASs), Figure 6, are characterized by their size and weight, making them unsuitable for transport or launch by a single individual. These UASs are notably larger than small systems but still smaller than typical light manned aircraft. Their wingspans usually fall within the 5-to-10-meter range, and they are capable of carrying payloads that typically weigh between 100 and 200 kilograms. Medium UASs are often deployed for intelligence, surveillance, and reconnaissance (ISR) missions, which can involve various sensors and communication equipment. Due to their size and operational requirements, these UASs generally need dedicated launch and recovery systems, as well as specialized ground support equipment to facilitate their deployment and retrieval.

Representative examples:

  • Hunter (wingspan ~10.2 m; length ~6.9 m; takeoff weight ~885 kg).
  • UK Watchkeeper.
  • RQ-2 Pioneer; BAE Systems Skyeye R4E; Boeing Eagle Eye.
  • RS-20 (crossover small–medium characteristics).

 

Sketch of the Pioneer, Skyeye, Hunter, Watchkeeper, Fire Scout, and Eagle Eye UASs.
Figure 6 Examples of medium UASs
Paul Fahlstrom and Thomas Gleason, 2012, Introduction to UAS Systems, 4th edition, Wiley)

Large UASs

Large UASs, Figure 7, also known as unmanned aerial vehicles, are sizable aircraft-scale platforms designed for missions that require extended endurance and operation at high altitudes. These systems are frequently deployed in scenarios involving combat, surveillance, or intelligence gathering, where their ability to remain airborne for long durations is critical. Due to their substantial size and advanced capabilities, large UASs can function within airspace typically reserved for traditional manned aircraft. They are equipped with state-of-the-art payloads, including sophisticated sensors and targeting equipment, as well as robust long-range communication systems, enabling them to carry out complex and demanding operations over vast distances.

Representative examples:

  • MQ-1 Predator A.
  • MQ-9 Predator B (Reaper).
  • RQ-4 Global Hawk (including NASA variants), Figure 8.

 

Sketch of Predator A, Harfang, and Global Hawk UASs.
Figure 7 Examples of large UASs
Paul Fahlstrom and Thomas Gleason, 2012, Introduction to UAS Systems, 4th edition, Wiley

 

Image of NASA's Global Hawk in an aircraft hanger with people walking around it.
Figure 8 NASA's Global Hawk
NASA