David Hambling
Forbes
April 4, 2024
While the U.S. is cautious about providing Ukraine with long-range strike capability, the Ukrainians are forging ahead with homebuilt solutions. Some of these are simple but bold expedients like packing a light aircraft with explosive and operating it by remote control but one new drone is a small masterpiece of elegant, low-cost engineering.
HI Sutton has compiled the definitive catalog of sixteen different types of Ukrainian long-range strike drone, which stand in direct contrast to Russia’s single type – the Shahed, designed in Iran. One of these Ukrainian types is now appearing in increasing numbers, and attracted the attention of physicist and online OSINT analyst DanielR who was intrigued by its simple design which used common materials in uncommon ways and has made a study of its construction from Russian imagery. We do not know its Ukrainian name, so it will be referred to here by its most distinctive feature as the drainpipe drone. “This is a very interesting and quite nice drone,” DanielR told Forbes. “The people who made it know what they are doing. The over-all design is similar to radio-controlled aircraft built by hobbyists many, many years ago. However, the airframe has been carefully designed to use locally-sourced, low-cost materials.”
The fuselage of the drone, its backbone so to speak, is what looks like length of orange plastic drainpipe six inches in diameter. DanielR was puzzled by the color choice, until European commenters told him that orange is the standard code for pipes carrying underground electrical cables in Europe, and six inches is the usual diameter. So the makers simply acquired sturdy PVC piping off the shelf.
The wings are constructed like model aircraft wings: the main support or spar is an aluminum tube, and the wing is given shape by machine-cut wooden ribs. It is covered with heat-shrink plastic film similar to that used to winterize boats which adds strength and minimizes drag. The shape of the wing is maintained by a set of foam inserts. “A neat design feature is that the wing and tail ribs also form the hinges for the control surfaces. The aft part of each rib contains a hole for a hinge rod. This is a very simple solution,” says DanielR.
Each of the three tail pieces is left-right and top-bottom symmetric so the vertical and horizontal pieces are interchangeable, simplifying manufacturing.
Some versions of the drone have an undercarriage, but later images show just wedges, suggesting that the Ukrainians have switched to launch from a rail or dolly – possibly launching from the roof of a car, as some Iranian drones do.
The fuel tank consists of a set of plastic water bottles joined together; from the appearance it has four five-liter bottles for a total of twenty liters/5.3 U.S. gallons.
The propeller is driven by a Chinese-made DLE-170 gasoline engine, sold as suitable for drones. This weighs about 4 kg/ 9 lbs. and develops 17.5 HPHPQ -0.1%. This engine is currently available on AliExpress for $1100 and is definitely the most expensive part of the drone.
Online discussions of fuel consumption for the DLE170 indicate that at normal rates of fuel usage it will fly for something like two and a half hours, which could take it 200-300 km/ 120-190 miles. Which is about the same as the ATACMS long-range missiles which Ukraine has been fruitlessly requesting from the U.S. since 2021.
The drone’s flight controller – the brain, converting navigation instructions into control signals for the flight surfaces – Pixhawk PX4 2.4.8 , widely used by drone hobbyists available for $108 on AliExpress. It also has a standard GPS receiver for navigation, and a device called a pitot which gives airspeed information.
DanielR also spotted a mysterious black box on the drone’s right wing. This is connected to the flight controller and may be part of a backup navigation system.
Russia routinely jams and spoofs GPS and other satellite navigation signals over its territory as a defence against drones. Some Ukrainian long-range drones are reportedly equipped with a machine vision navigation system which scans the landscape below to find its way on a map. “There has been no conclusive photograph of a camera,” DanielR told Forbes. “But a camera would likely be mounted under the fuselage, away from the exhaust, where it would be hard to see.”
A camera would also allow the drone to employ the next level of drone autonomy – an automated recognition system to precisely locate the target when it gets to the right area. Ukrainian researchers are already fielding early versions of this technology using low-cost commercial hardware. “The munition is bolted to the airframe, so one can assume it is meant as a medium-range kamikaze [rather than a bomber],” says DanielR.
The warhead appears to be about 12 cm diameter and 25 cm long, so may be no more than three kilos / 7 pounds of explosive, similar to the one on Ukraine’s Morok attack drone.
The small warhead may also be a sign that the drone has relatively advanced guidance, as it requires a direct hit to damage most targets.
This may not be the drone’s main weapon though. As with some missiles, the ignition of unexpended fuel may do more damage than the explosive. The drone is essentially a giant, flying Molotov cocktail. Given that many of the current prime targets are Russian gas and oil storage and refineries, the drainpipe drone may be intended as more of a Firestarter than a blaster, especially if used as a second wave after drones with bigger warheads have ruptured storage tanks.
The drainpipe drone is designed for maximum simplicity and ease of production. DanielR estimates that it could be made by two people at a cost of $5-$10k. “It has been designed to be easy to build and deploy,” says DanielR.
One commenter apparently with experience suggested that a dedicated workshop could turn out twenty of the drones in a day. The main limitation is likely to be the supply of parts, which in this case are all plentiful. It is not easy to see how the drone could be improved. “In spite of its simplicity, the airframe is refined so I am not expecting to see any big changes to its design,” DanielR told Forbes, noting that any evolution is likely to be internal. “This is a fairly large drone and can easily accommodate different flight controllers and other electronics.”
For all its crude looks the drainpipe drone is a modern, modular weapon which can easily be upgraded with more advanced electronics and different warheads or other payloads as required. It carries a much smaller payload than a million-dollar ATACMS missile, but has similar accuracy and range. Ukraine can acquire them without foreign assistance…and launch them without permission from foreign partners.
The main function of drainpipe drones may be to stretch and confuse Russian defenses. This is the old concept of an ‘armed decoy’, which is not a major threat itself but which defenders cannot afford to ignore and which enables other attacks. Volleys of such drones will force the Russians to expend scarce surface-to-air missiles, diluting their efforts and paving the way for attacks by more powerful drones.
In large numbers though, if they can strike accurately, drainpipe drones might be highly effective in their own right. Other states and non-state actors will be taking note.
David Hambling is a freelance science and technology journalist and author based in South London. His non-fiction books include Weapons Grade, Swarm Troopers: How small drones will conquer the world and We: Robot. His Lovecraftian science fiction includes the popular Harry Stubbs series set in 1920s South London, and his time-travel adventure City of Sorcerers will be out in 2022.