Balancing Cost, Performance and Weight in Designing UAVs

September 1, 2025

Recent years have seen a significant rise in medium sized drones across a huge range of applications. In agriculture, for example, drones are used to monitor livestock and map soil quality to prevent the over-application of fertilizer. In archaeology, they’ve been used for surveys and to track looting – for example conservation NGOs are using them to monitor biodiversity and prevent poaching.

Traditionally, many of these applications have operated within tightly constrained budgets, often prioritizing affordability over durability. As a result, lower-cost drones using inexpensive components – with inherently higher failure rates – have been the norm, especially for uses in remote or low-risk environments. However, the use of UAVs is increasing rapidly - including their use for delivery in highly populated areas by Amazon, DHL and other logistics firms, meaning the balance between cost and performance is becoming a more pressing concern.

Amazon has been using its Prime Air drones, pictured here, to deliver packages to customers in select communities across the U.S. since 2022, including Texas and Arizona. The cost of a drone delivered package from Amazon is partly determined by the weight of packages being delivered. For example, in a November 2024 article published by Amazon, the company notes that customers living near Tolleson, Arizona can purchase an item weighing 5 pounds or less and have it delivered by drone in under an hour. (Image: Amazon)

In a report about beyond visual line of sight (BVLOS) drone operations published by the U.S. Department of Transportation Office of Inspector General (OIG) on July 8, 2025, the agency notes that the Federal Aviation Administration had registered 361,000 commercial drones at the beginning of 2024. The report expects that number to grow to 1 million by 2027.

While all systems – be they a cell phone or a sports car – to a greater or lesser extent are subject to size, weight, power and cost (SWaP-C) trade-offs, these constraints are especially prevalent when it comes to the design of UAVs. These systems need to stay airborne for long periods of time, often while carrying large payloads.

Heavier payloads require more power to achieve lift and maintain flight and according to a 2019 study from researchers at the University of Michigan, adding just one kilogram to a drone’s payload can reduce its flight time by up to 30 percent.

Connectors and cable assemblies collectively represent a significant proportion of the UAV system mass and in this article, we will examine how some of the innovations that were developed for the high-reliability connector ranges – for use in military jets or Formula-1 cars – are making their way to lower-cost industrial models. We’ll also look at how this enables OEMs to balance both the performance / reliability demands within the cost pressures being faced by commercial-application UAV developers.

Walmart uses drones operated by Wing to deliver packages to customers in select areas of Texas and Arizona, and has plans to expand to Florida over the next year as well. The drone operated by Wing for Walmart deliveries has a carrying capacity of up to five pounds, with a range of up to six miles at a cruising speed of 65 mph. (Image: Walmart)

Military UAVs

Before we get to that, let’s first look at tactical UAVs used by the military. These are required to fly up to 160 km, and HALE (high altitude, long endurance) surveillance drones go far further. The nature of their operational environment means they need the ability to function reliably, while working in high-vibration situations, sub-zero temperatures and low-pressure atmospheric conditions. At the same time they need to be as small and lightweight as possible.

Unmanned vehicles such as these integrate interconnect that have been designed with a focus on the SWaP of SWaP-C. They use the latest developments in materials science with alternative layouts that enable lighter, slimmer designs and the smallest possible pitches as well as the best possible electrical conductance.

On the materials side, this means metal alloys, reinforced composites and lightweight thermoplastics. Similarly, conductive materials, such as beryllium copper or thin film coatings of gold are used to increase the electrical conductivity, prevent corrosion and improve mating performance with the minimal of weight addition.

When it comes to design, leading edge connectors offer single and double-row layouts as well as angled (vertical to vertical / vertical to horizontal) variants and the integration of both signal and power on the same device, which enables the reduction of components (and therefore weight) and allows for more aerodynamic designs.

High reliability connectors are also designed to cope with vibration, shock, temperature extremes and low-pressure environments.

Commercial Drones

But the drones intended for use in logistics, or agriculture aren’t leading-edge systems. And cost is very much a primary consideration.

As such, many of the drones used to map nutrients in the soil of a farm, scan archaeological sites, undertake home deliveries, or transport medical supplies to remote areas need to work within exceptionally tight cost constraints while still developing systems that maximize work time (i.e. range), and reliability.

The move to drones for applications such as logistics and medical supply transport brings several benefits. For example, a 2022 paper from Carnegie Mellon University found automated drone delivery in logistics (a sector responsible for 37 percent of all transportation-related CO2 emissions) not only reduced transportation time significantly but also reduced the energy per package by up to 94 percent versus other transport types – with only electric cargo bikes being more efficient.

However, a December 2024 study analyzing the adoption of drones for multi-modal logistics in a healthcare setting published in the journal Transport Economics and Management posited that cost is the biggest barrier to widespread drone uptake. So how can drone manufacturers reduce component costs without risking reliability?

Leveraging Connectors to Reduce Drone Weight

While connector ranges developed for the most demanding environments may be out of reach, the learnings gained in the development of high-reliability technologies are not. Indeed, they are starting to make their way into the lower-cost industrial connectors.

For example, Harwin’s Kontrol range of connectors has been designed for high vibrational stress, with components tested to withstand 20 Gs continuously for 12 hours. Similarly, they incorporate reliable-mating features such as shrouded pins and secure latching mechanisms that help maintain a secure connection despite the vibration that will come from a multi-copter drone’s rotor blades.

Advances that have allowed miniaturization in the flagship ranges are also starting to appear in industrial connectors, with both smaller pitches and mixed layout / hybrid connectors. These enable the combination of both power and signal in a single unit, and therefore reduce the total number of connectors required on the board.

Weight can also be saved through the optimization of the cable assemblies. While metal braids may be needed in some cases to provide durability and EMC shielding, shifting to lighter materials where possible can also have a notable effect on the total mass of the vehicle.

Reducing the number of connectors not only lowers the system weight but also enhances reliability, with the risk of connector misalignment increasing with each connector added.

To counter this, floating connector ranges enable movement in the X and Y axes, which enables greater tolerance when multiple connectors are used to connect the same two PCBs. For example Harwin’s fine-pitch, high-pin-count Flecto board-to-board connector range can withstand up to ±0.5mm misalignment in each axis.

Harwin’s Gecko MT is the company’s smallest and lightest range of mixed layout connectors. Signal pins are spaced at just 1.25mm and are the connectors are rated to meet the most vibration, shock and temperature extremes. (Image: Harwin)

And, in addition to advanced products, reputable suppliers are advancing their offering by providing a range of tools that, for example speed the identification, selection, and prototyping of connector applications.

Vendors will also provide comprehensive documentation to cover everything from product specifications to test report summaries and from product training to tooling instructions. And by working with advanced-technology companies to implement industrial connector ranges with technologies initially developed for high-reliability ranges, system developers can reduce weight without compromising on mandated reliability standards.

Supply Chain Reliability

One final note. With reliability and cost both being vital in commercial drones, it is always tempting to source the best possible deal.

But the trustability of the supplier should be a key factor when sourcing components with counterfeit and low-quality components entering the market. There are even examples of websites taking orders for stock they don’t (and never will) have. Reputable distributors are therefore essential.

Like many other companies, Harwin uses a franchised distribution model with ECIA standards in place to prevent fraudulent or counterfeit parts, for example listing distribution partners listed on the website as well as on TrustedParts.com and any company that claims to be a partner that isn’t on these lists should be avoided.

This article was contributed by Harwin (Portsmouth, UK). For more information, visit here .