HDRX-R Series

Two-Stage Hydrogen Regulator for Fuel-Cell UAVs

Stable hydrogen delivery from 350–500 bar storage, configured to your fuel cell’s required inlet pressure and peak flow.

350–500 barSupply pressure classes
0.2–10 bargConfigured outlet range
Two-stagePressure regulation
~245 gTarget regulator mass
M18 × 1.5Direct cylinder interface

Send us your fuel-cell model or datasheet. Our engineering team will propose the correct outlet pressure, flow configuration, interfaces, price and lead time.

Development programme · configuration quotations open · qualification units planned 2027 Q2
MEYER HDRX-R two-stage hydrogen regulator for fuel-cell UAVs — M18 x 1.5 cylinder interface
Ø 65 mm · ~245 g target · M18×1.5 · SS 316
Built forFixed-wing UAVsVTOL aircraftLong-endurance dronesFuel-cell research platformsLightweight mobile power

Configured for fuel cells from manufacturers including Intelligent Energy, H3 Dynamics, Spectronik and Honeywell, and other compact PEM fuel-cell systems. Manufacturer names identify compatibility targets from public datasheets — no affiliation or endorsement implied.

A fuel cell does not simply need lower pressure — it needs stable pressure throughout the flight

A high-pressure hydrogen cylinder can begin a mission at 350–500 bar and finish at a small fraction of that. At the same time, hydrogen demand changes through take-off, climb, cruise and power transients. The regulator must hold the fuel-cell inlet inside its permitted window despite falling cylinder pressure, changing hydrogen flow, temperature variation and rapid load changes — which is why the HDRX-R uses a two-stage architecture: the second stage works from a near-constant intermediate pressure, so the outlet barely notices the cylinder emptying.

Swipe sideways for the full schematic →

SUPPLY 350 bar 5,000 psi 2-STAGE · SS316 OUTLET ±0.1 bar 0.9 barg 15 SLPM FUEL-CELL STACK example: IE-SOAR 800W window
The regulator is not selected by cylinder pressure alone. It must be matched to the fuel cell’s inlet-pressure window, nominal and peak hydrogen flow, minimum cylinder pressure, operating temperature, connection requirements and transient response — which is why every HDRX-R is configured, not picked from a shelf.

One regulator platform, configured for your fuel cell

The HDRX-R is built around a configurable regulator platform: the pressure class, outlet setpoint, flow capacity and interfaces are defined for your specific fuel-cell system. You do not select from a generic industrial list — MEYER reviews the application and issues a controlled regulator configuration with its own part number.

Stable two-stage regulation

Designed to limit outlet-pressure variation as cylinder pressure falls during operation — held to ±0.1 bar of setpoint as standard.

Fuel-cell-specific configuration

Outlet pressure and flow capacity are selected against the actual fuel-cell requirements, from its current manufacturer datasheet.

Lightweight direct mounting

Designed for direct installation on MEYER and other M18 × 1.5 cylinder interfaces — no high-pressure interstage plumbing.

High-pressure hydrogen compatibility

Wetted materials and sealing components selected for compatibility with high-pressure gaseous hydrogen service.

Technical specifications

ParameterHDRX-R specificationStatus
GasGaseous hydrogen · helium and other media on reviewConfigurable
Supply pressure350 / 400 / 450 / 500 bar classesConfigurable
Outlet pressure0.2 – 10 barg, set at order · held to ±0.1 barConfigurable
Regulation architectureTwo-stageDesign fixed
FlowConfigured to nominal and peak stack demand (SLPM)Configurable
MassApprox. 245 gDesign target
EnvelopeØ 65 mm · STEP reference envelope on requestDesign target
Cylinder connectionM18 × 1.5 · 17E, 25E, 3/4″-16 UNF, 5/8″-18 UNF, M12×1 optionsStandard
Outlet connectionM8 × 1.25 · customer-selected interfaces on requestConfigurable
Wetted body material316 / 316L stainless steelDesign fixed
MountingDirect cylinder mount · remote mounting on reviewConfigurable
DocumentationConfiguration record, series datasheet, STEP reference envelopeStandard

Legend: Configurable set per order · Design fixed platform architecture · Design target pre-production value, confirmed at qualification · Standard included. Final specification depends on outlet pressure, flow, temperature and interface configuration — MEYER issues a controlled specification for each quoted regulator.

Configure the regulator for your fuel cell

Select your fuel-cell system — or state your own numbers. MEYER reviews the pressure and flow requirements before issuing a quotation; compatibility is confirmed by engineering review, not by the form.

3 stepsConfigure the regulator for your fuel cell1 Fuel cell2 Supply3 Request

Which fuel cell do you fly?

Not listed? Choose “custom” — we fit any stack: any outlet, any flow. Fitted figures per manufacturer datasheets.

Typical fuel-cell configurations

Browse allFitted configurations by fuel cellInlet figures per manufacturer datasheets · outlet held to ±0.1 bar · rows open the configurator above

Swipe sideways for the full table →

Fuel cellPowerH₂ inlet (datasheet)Fitted flowYour regulator
IE-SOAR 650W (legacy) Intelligent Energy650 W0.5 ± 0.25 bar10 SLPM fitted, sizedHDRX-R350…Fit to my FC →
IE-SOAR 800W Gen2 Intelligent Energy800 W0.9 ± 0.1 bar.g15 SLPM fitted, sizedHDRX-R350…Fit to my FC →
IE-SOAR 1.2kW (legacy) Intelligent Energy1.2 kW0.5 ± 0.25 bar18 SLPM fitted, sizedHDRX-R350…Fit to my FC →
IE-SOAR 2.4kW Intelligent Energy2.4 kW0.9 ± 0.1 bar.g50 SLPM fitted, datasheet peakHDRX-R350…Fit to my FC →
Aerostak A-250 H3 Dynamics / HES250 W0.6 – 0.8 bar5 SLPM fitted, datasheetHDRX-R350…Fit to my FC →
Aerostak A-500 H3 Dynamics / HES500 W0.6 – 0.8 bar8 SLPM fitted, datasheetHDRX-R350…Fit to my FC →
Aerostak A-800 H3 Dynamics / HES800 W0.6 – 0.8 bar12 SLPM fitted, datasheetHDRX-R350…Fit to my FC →
Aerostak A-1000 H3 Dynamics / HES1 kW0.6 – 0.8 bar17 SLPM fitted, datasheetHDRX-R350…Fit to my FC →
Aerostak A-1500 H3 Dynamics / HES1.5 kW0.6 – 0.8 bar26 SLPM fitted, datasheetHDRX-R350…Fit to my FC →
Aerostak A-2000 H3 Dynamics / HES2 kW0.6 – 0.8 bar30 SLPM fitted, sizedHDRX-R350…Fit to my FC →
Protium-300 Spectronik300 W0.4 – 0.7 bar5 SLPM fitted, datasheetHDRX-R350…Fit to my FC →
Protium-1000 Spectronik1 kW0.7 bar (10 psig)16 SLPM fitted, datasheetHDRX-R350…Fit to my FC →
Protium-2500 Spectronik2.5 kW0.7 bar (10 psig)40 SLPM fitted, datasheetHDRX-R350…Fit to my FC →
Protium-3000 Spectronik3 kW0.7 bar (10 psig)48 SLPM fitted, datasheetHDRX-R350…Fit to my FC →
600U / 600U-HV Honeywell600 W12 – 18 psi (≈0.8–1.2 barg)10 SLPM fitted, sizedHDRX-R350…Fit to my FC →
1200U Honeywell1.2 kW12 – 18 psi (≈0.8–1.2 barg)19 SLPM fitted, sizedHDRX-R350…Fit to my FC →

Bundled fuel-cell regulators typically stop at 350 bar supply and ≤1 barg outlet — the HDRX-R series covers 350–500 bar supply and 0.2–10 barg outlet, set to order and held to ±0.1 bar as standard. Inlet figures quoted from the manufacturers’ public datasheets; trademarks belong to their respective owners — no affiliation or endorsement implied; verify against your fuel cell’s manual revision. Fuel cell not listed? Choose “custom” in the configurator above or tell us.

Engineering files

Datasheet lands in your inbox within a minute; CAD requests are answered personally.

One supplier for hydrogen storage and pressure delivery

MEYER supplies the regulator alone or as part of a matched COPV + regulator system. Sourcing storage and regulation from one supplier removes interface uncertainty and simplifies pressure-class selection, cylinder-valve compatibility, mounting design, system mass estimation, filling architecture, leak testing, documentation — and supplier responsibility.

Regulator only

For programmes with an existing approved hydrogen cylinder. Configured regulator, controlled specification and installation instructions.

Storage + regulation assembly

Matched MEYER COPV (hydrogen catalog), cylinder interface, HDRX-R regulator, selected ports and fittings, combined system documentation.

Development integration kit

For prototype and research programmes: COPV + regulator, fill adapter, selected connections, operating instructions and engineering support.

Ask for a complete system proposal in the configurator notes, or state it in your quotation request — the configurator’s COPV line adds the cylinder to your part-number configuration.

Documentation prepared for engineering integration

Series technical datasheet (REV B, 4 pages)
Regulator configuration record — per quoted unit
STEP reference envelope — on request
Controlled specification per configured part number
Installation and interface instructions — with order documentation
Conformity documentation per applicable marking — see qualification & approvals
Individual pressure- and leak-test records — issued with qualification units
Qualification report — follows the qualification campaign

Each configured regulator carries a unique part number tied to its approved pressure, flow, connection and testing requirements. ✓ available now · ○ issued at the programme stage indicated.

HDRX-R programme status

Two-stage platform architectureDefined
Supply-pressure classes (350–500 bar)Defined
Fuel-cell fitted-configuration engineeringActive
Configuration quotationsOpen now
Qualification unitsPlanned 2027 Q2
Series productionFollowing qualification

Qualification units are intended for established fuel-cell developers, UAV OEMs and engineering programmes able to provide structured integration feedback — apply through the configurator, or state your programme in the quotation notes.

Choose the right programme stage

Application review

Fuel-cell datasheet review, preliminary regulator configuration, interface recommendation and budgetary quotation.

Request application review →

Development unit

Configured development regulator with engineering documentation and integration support — for prototype aircraft and laboratory systems.

Request development pricing →

Series programme

Configuration control, qualification planning, production documentation and volume pricing — for UAV OEMs and recurring production.

Discuss series supply →

Pricing is provided after application review.

Choose your supply pressure class

HDRX-R350350 bar hydrogen regulator — the match for every MEYER catalog hydrogen cylinder, from the 0.5 L HDRX-005-H2 to the 40 L HDRX-400-H2. The standard choice for fuel-cell UAS flying today. Browse the 350 bar cylinders
HDRX-R400400 bar hydrogen regulator — headroom for higher-density systems and cylinder configurations operated above catalog pressure under project qualification.
HDRX-R450450 bar hydrogen regulator — the class our original drone regulator was built in: R&D programs running reduced-safety-factor cylinder configurations and 450 bar fill infrastructure.
HDRX-R500500 bar hydrogen regulator — for 500 bar systems and forward-looking platforms: maximum energy density per cylinder volume.

Two-stage vs. single-stage — the engineering background

The two variables that decide whether a stack sees its specified inlet for the whole flight are droop (outlet change with flow) and supply-pressure effect (outlet change as the cylinder empties). The full argument, illustrated:

Single-stage
  • One reduction step, cylinder to outlet
  • Little droop with varying flow
  • Large supply-pressure effect — output drifts upward as the cylinder empties
  • Can leave a low-pressure PEM stack’s inlet window mid-flight
Two-stage — every HDRX-R
  • Two reduction steps — the second stage sees a near-constant inlet
  • Some droop, sized in at fitting (flow chosen for your peak demand)
  • Minimal supply-pressure effect — constant delivery from full cylinder to empty
  • No readjustment in service — set, verified, sealed
Delivery pressure over a flight — single-stage vs two-stage FUEL-CELL INLET WINDOW ±0.1 bar 350 bar cylinder pressure during the flight → empty outlet two-stage single-stage drift leaves the stack’s window as supply falls

Supply-pressure effect, illustrative: a single-stage regulator’s delivery pressure rises as the cylinder empties; two-stage regulation holds the setpoint across the whole flight.

BENCH DEMONSTRATION Single-stage vs two-stage: supply-pressure effect, on camera single-stage drifts two-stage holds PLAY · 2 MIN

Helium and other lightweight gas applications — airships, aerostats, balloon-launch systems — have their own page: helium regulators. The physics in 60 seconds: why two-stage.

Frequently asked questions

Can the regulator be used with any fuel cell?The platform can be configured for different fuel-cell pressure and flow requirements. The fuel-cell datasheet is reviewed before compatibility is confirmed — compatibility is never assumed from form data alone.
Why is two-stage regulation used?Two-stage regulation reduces the effect of changing cylinder pressure and holds a narrower outlet-pressure band throughout operation — the second stage works from a near-constant intermediate pressure.
Can the regulator mount directly on the cylinder?Yes — the standard platform is designed around an M18 × 1.5 cylinder interface (17E, 25E, UNF and M12 options). Remote-mounting configurations can be evaluated per project.
Is the regulator available now?The HDRX-R is in its development programme: configuration quotations are open now, and qualification units are planned for 2027 Q2, allocated to programmes able to provide structured integration feedback.
Can MEYER supply the hydrogen cylinder as well?Yes — MEYER proposes matched COPV + regulator systems with controlled interfaces and combined documentation. The configurator’s COPV line adds the cylinder to your configuration.
What information is needed for a quotation?At minimum: fuel-cell model or datasheet, maximum cylinder pressure, required outlet-pressure range, nominal and peak flow, and connection requirements. Prototype and annual quantities help us propose the right programme stage.
Can you provide CAD files?Yes — STEP reference-envelope files are provided on request via the engineering-files form; toleranced models follow with order documentation.

Send us your fuel-cell specification

MEYER will propose a regulator configuration matched to your fuel-cell inlet pressure, peak hydrogen flow, cylinder pressure and connection requirements.

You will receive a proposed part number, technical specification, price and estimated lead time after engineering review.

Scroll to top