For asset owners and service providers: what separates a drone that looks inside a vessel from one that measures wall thickness in it.
Book a dive briefingWhat this compares
Confined space inspection drones exist because entry is the most expensive part of an internal inspection. A vessel, a boiler, a cargo tank or a stack has to be cleaned, ventilated, gas-tested, scaffolded and permitted before a person goes in, and everything upstream of that is downtime. A drone that can fly inside a closed asset moves the inspection from a permit-controlled entry to a hatch and an operator.
The table below compares eight platforms on the specifications that decide whether one fits your asset: how wide it is, how long it flies, how much light it carries, what the camera resolves, whether it can take a measurement rather than a picture, what software comes with it, and what it costs.
The figures are the manufacturers' own. Where a price is a reseller quote or an estimate, the table says so, and where a value was not published we left it blank rather than filling it in. Three rows carry no lumen figure for exactly that reason.
The comparison
Eight collision-tolerant platforms compared on size, endurance, lighting, camera, NDT payload, data platform and price. The full-resolution version is available as a PDF.
Download the comparison (PDF)The table
The figures are the manufacturers' own. An em dash means the value was not published, not that it is zero. Three rows carry no lumen figure for that reason.
| Platform | Size (W × H) | Endurance | Lighting | Camera | NDT payload | Data platform | Price |
|---|---|---|---|---|---|---|---|
| Flyability Elios 3 | 480 × 380 mm | 12 min 30 s · unlimited on tether · 7 min with LiDAR + UT | 16k lm | 4K/30, 4000 × 3000 stills, thermal | Dual-crystal UT (2 / 5 / 7.5 MHz), cleaning module | Inspector 5, asset management | 55k–120k USD, est. |
| ScoutDI Scout 137 | 382 × 303 mm | Unlimited, tethered to 40 m | > 12k lm | 4K/30, 3840 × 2160 | Multigauge 6000, single-crystal UT (2.25 / 3.5 / 5 MHz) | Scout Portal, API, live streaming | 45k–80k USD, est. |
| Flybotix ASIO X | 406 × 305 mm | 20 min with LiDAR | 40k lm | 4K/30, infrared | not published | ASIO Explore & Connect, AI defect recognition | 45,995 USD + 4,995 USD/yr |
| Multinnov Stereo 2 | 390 mm | 12 min | 10k lm (4 panels) | 4K, 3840 × 2160 | not published | Third-party photogrammetry | 20k USD, est. |
| CIS Inspec 2 | 399 mm | 14 min | 12k lm | 4K, 3840 × 2160 | not published | not published | 25k USD, est. |
| Cleo Dronut DD1 | 190 × 115 mm | 15 min with LiDAR | not published | 4K + 3 global-shutter (1280 × 800) | not published | 4K video and LiDAR recording | 19,995 USD (reseller) |
| Lumicopter | 426 × 364 mm | 9.5 min | 4k lm (4 LEDs) | 4K/60, 3840 × 2160 | not published | not published | 6,500 USD (reseller) |
| Terra Drone Terra Xross 1 | 360 × 210 mm | 10 min with LiDAR · unlimited tethered | not published (8 LEDs) | 4K, 3840 × 2160 | not published | Terra Xross Cloud | 24,500 USD (reseller) |
Source: manufacturer specifications, compiled by 8scale · As of 15 September 2025
Start with the opening, not the drone. Widths in the table run from 190 mm for the Cleo Dronut DD1 to 480 mm for the Flyability Elios 3 - a factor of two and a half. A 24-inch manway takes any of them; a 12-inch inspection port takes one. Measure the smallest opening on the route in, not the nominal size on the drawing.
Then read the endurance figure twice. The Elios 3 is listed at 12 min 30 s on its base configuration - and at 7 minutes with LiDAR and the ultrasonic probe fitted. That is the number that matters, because that is the configuration you would fly for a thickness survey. Across the table, battery endurance runs from 9.5 to 20 minutes, which is one to two hatches per battery, not one to two hours.
Where sorties matter more than manoeuvrability, tethers change the arithmetic. The ScoutDI Scout 137 flies unlimited on a tether up to 40 m, the Terra Xross 1 is listed as tethered unlimited, and Flyability offers a tethered power unit with the same unlimited endurance. A tether is a cable to manage and a range limit to plan around, and in exchange the inspection stops being a series of battery swaps.
Lighting is the specification that most often disappoints on site, and it has the widest spread in the table: 4,000 lumens on the Lumicopter against 40,000 on the Flybotix ASIO X, a factor of ten. Inside a coated black vessel, light is what decides whether the 4K sensor sees a crack or a grey smear. Three of the eight publish no lumen figure at all - ask for it before the demo.
For asset owners
Seeing against measuring
Every platform in the table records 4K video, and six of the eight resolve stills at 3840 x 2160. Camera specification has stopped being a differentiator - it is a floor, not a feature.
The real line runs through the NDT column. Two platforms carry an ultrasonic thickness probe: the Elios 3 with a dual-crystal probe arm at 2, 5 and 7.5 MHz, and the Scout 137 with a Multigauge 6000 arm using single-crystal probes at 2.25, 3.5 and 5 MHz. Both give a live A-scan and tag the reading to a 3D location. The other six report 'not available'.
That distinction decides what the flight is worth. A visual drone answers 'does this need a closer look', and it answers it without an entry - which is already most of the saving. A UT-capable drone answers 'how much wall is left here', which is the number that goes into a fitness-for-service case and the reason the entry was scheduled at all. The first defers a decision; the second can close one.
Both probe arms need surface contact, which is why both vendors list a cleaning module - shipping on the Elios 3 for light dust, in development on the Scout 137. A thickness reading through scale is not a thickness reading, so ask what surface preparation the quoted accuracy assumes.
Hardware in the table runs from 6,500 USD for the Lumicopter to a 55,000-120,000 USD range for an Elios 3 with accessories - a factor of eighteen across platforms that all fly inside closed assets and all record 4K. The two ends are not competing for the same job. The upper end buys a measurement capability and a support structure; the lower end buys a camera that survives contact.
Note how the prices are quoted. Four are reseller figures, three are estimates, and only the two NDT-capable platforms are given as ranges - because at that end the configuration, the probe set and the accessories move the number more than the airframe does. Budget against the configuration you will actually fly.
The line that does not appear in a purchase order is software. Four of the eight ship a data platform: Flyability with Inspector 5 and asset management, ScoutDI with the Scout Portal and an API option, Flybotix with ASIO Explore and Connect, Terra Drone with Terra Xross Cloud. Flybotix is the only vendor here that names the recurring price - ASIO Explore at 4,995 USD per year. The other three do not publish one, which does not mean it is free.
For a service provider that is the pricing question, not the hardware. Rope access and manual UT sell hours; a drone sells a data set, and the data set is what the platform stores, indexes and hands back. Who owns that archive after the contract, and what it costs to keep reading it, belongs in the quote.
For service providers
The eight platforms
01
480 x 380 mm, 16k lumens. Base 12 min 30 s, unlimited on the tethered power unit, 7 min with LiDAR and UT fitted. Dual-crystal UT probe arm (2 / 5 / 7.5 MHz), thermal camera, 4000 x 3000 stills. Inspector 5 and asset management software. 55k-120k USD with accessories, estimated.
02
382 x 303 mm, over 12k lumens. Tethered, unlimited to 40 m. Multigauge 6000 probe arm with single-crystal UT (2.25 / 3.5 / 5 MHz), cleaning module in development. Scout Portal with API and live streaming. 45k-80k USD with accessories, estimated.
03
406 x 305 mm and 40k lumens - the brightest in the table by a factor of two and a half. 20 min with LiDAR. Infrared camera, no UT. ASIO Explore and Connect with AI defect recognition. 45,995 USD, with ASIO Explore at 4,995 USD per year.
04
390 mm, 10k lumens from four panels, 12 min. 4K video and stills, no UT payload. No first-party platform - third-party photogrammetry. 20k USD, estimated.
05
399 mm, 12k lumens, 14 min - the longest battery endurance here without LiDAR. 4K video and stills, no UT payload and no data platform listed. 25k USD, estimated.
06
190 x 115 mm - less than half the width of anything else in the table, and the only one that fits a small inspection port. 15 min with LiDAR. Three global-shutter cameras alongside the 4K. Lumens not published. 19,995 USD from a reseller.
07
426 x 364 mm, 4k lumens from four LEDs, 9.5 min - the shortest endurance and the dimmest lighting in the table, and by a wide margin the cheapest. 4K at 60 fps. 6,500 USD from a reseller.
08
360 x 210 mm, eight LEDs with no published lumen figure. 10 min with LiDAR, unlimited tethered. Terra Xross Cloud ties captured images and video to 3D data. 24,500 USD from a reseller.
COMMON QUESTIONS
For the visual part of an internal inspection, often yes – and that is where the saving sits, because the entry itself is what requires cleaning, ventilation, gas testing, scaffolding and a permit. For anything that needs contact with the wall, only the two platforms in this comparison with an ultrasonic probe arm can answer without a person inside, and both need the surface prepared.
The smallest opening on the route into the asset. Widths in this comparison run from 190 mm to 480 mm, so the access port rules out most of the field before any other specification matters. Check it against the real opening, not the nominal size on the drawing.
Because the drone carries its own lighting and, on the NDT platforms, a probe arm and LiDAR. Battery endurance in this comparison runs from 9.5 to 20 minutes, and the Elios 3 drops from 12 min 30 s to 7 minutes once LiDAR and the ultrasonic probe are fitted. Tethered platforms avoid the limit entirely, at the cost of a cable and a range.
Between 6,500 and 120,000 USD across the eight platforms here, and the spread tracks capability rather than airframe. Ultrasonic thickness measurement, a data platform and support account for most of the distance. Software is the recurring line: only one vendor in this comparison publishes it, at 4,995 USD per year.
If the inspection produces a record someone has to act on later, yes – the value of a drone flight is the indexed, located data set, not the footage. Four of the eight ship a first-party platform and two offer an API. Before signing, settle who owns the archive when the contract ends and what it costs to keep reading it.
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02
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03
Industrial robotics pilots fail on translation, not technology. What scaling beyond pilot actually demands.
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