Military Aviation Pressure Meter GY-250 250GKS/M3

Product Overview

The GY-250 250GKS/M3 is a high‑precision military aviation pressure meter (contactor) designed for critical pressure monitoring and switching in aircraft hydraulic systems, landing gear, brake circuits, and drone engine controls. This air pressure meter provides accurate measurement from 0 to 250 KGS (kgf/cm²) with a built‑in contact output for over‑pressure alarm or system shutdown. Featuring a robust stainless steel housing, high overload protection, and wide temperature compensation (-55°C to +125°C), the GY-250 is fully compliant with MIL‑STD‑810 environmental requirements. It is an essential component for military aviation, ground support equipment, and industrial hydraulic systems. As part of YM’s comprehensive instrumentation portfolio – which includes Aviation Temperature Sensor ZWH-2, Hydraulic Filter MQL-5, Aviation Hand Valve YSF-1A, Oxygen valve QF-21A, and Electronic Horn – the GY-250 delivers uncompromised reliability for flight‑critical pressure monitoring.

Technical Specifications

Pressure Measurement

• Measurement range: 0 – 250 KGS (kgf/cm²) – equivalent to 0 – 25 MPa / 0 – 3600 psi
• Overload pressure: 150% of full scale (375 KGS)
• Burst pressure: 200% of full scale (500 KGS)
• Accuracy: ±1.0% F.S. (typical); ±0.5% F.S. (high‑grade option)
• Hysteresis & repeatability: ≤0.5% F.S.
• Media compatibility: Hydraulic oil (MIL‑PRF‑83282, MIL‑PRF‑5606), fuel (JP-8, Jet A-1), pneumatic air, and nitrogen

Electrical & Contact Output (Contactor Function)

• Contact configuration: SPST (normally open) or SPDT – adjustable set point
• Maximum switching current: 5A at 28V DC (resistive); 2A at 115V AC 400Hz
• Initial contact resistance: ≤50mΩ; after life ≤200mΩ
• Insulation resistance: >500MΩ at 500V DC
• Dielectric strength: 500Vrms between contacts and case
• Electrical connection: MS3112 circular connector (MIL‑DTL‑26482) or pigtail leads

Mechanical & Environmental

• Pressure connection: 1/4” NPT, 1/8” NPT, or MS flare (AN815/816)
• Housing material: Stainless steel (17-4 PH) – corrosion resistant
• Diaphragm/sensor element: Stainless steel welded, oil‑filled for vibration damping
• Operating temperature range: -55°C to +125°C
• Storage temperature: -65°C to +150°C
• Vibration resistance: 20g RMS, 10-2000Hz per RTCA/DO‑160
• Shock: 50g, 11ms half‑sine
• Sealing (hermeticity): Leakage rate ≤10⁻³ Pa·cm³/s (glass‑to‑metal seal on electrical feedthroughs)
• Weight: ≤280g

All parameters are validated per MIL‑STD‑810G and MIL‑PRF‑39016 (for contactor section). The GY-250 is designed for 1×10⁵ mechanical cycles and 1×10⁶ pressure cycles.

Product Images & Visuals

Above: GY-250 series pressure meter (shown with 1/4” NPT port and MS3112 connector). Contact YM for dimensional outline, wiring diagram, and environmental qualification reports.

Key Features & Advantages for Military Aviation

• High precision & wide measurement range: 0‑250 KGS (3600 psi) with ±1.0% F.S. accuracy – ideal for hydraulic system monitoring in fighters, helicopters, and ground test stands.
• Integrated contactor output: Adjustable set point for over‑pressure alarm, pump shutoff, or secondary system activation – eliminates need for separate pressure switches.
• Hermetically sealed construction: Glass‑to‑metal seal and welded stainless steel housing protect against moisture, fuel, and altitude pressure changes – ensures reliable operation in unpressurized bays.
• Wide temperature & vibration tolerance: -55°C to +125°C and 20g vibration meet RTCA/DO‑160 – suitable for aircraft engine compartments and drone hydraulic actuators.
• Low contact resistance & high isolation: ≤50mΩ and >500MΩ ensure clean switching of avionics and power circuits.
• Compatible with multiple media: Hydraulic oil, jet fuel, air, nitrogen – one device for various fluid monitoring tasks.

YM’s engineering advantage: The GY‑250 combines a precision pressure sensor with a rugged Military Metal Relay contact output (derived from our Polarized Relay and Latching Relay technologies). Compared to separate pressure transducers and relays, this integrated design reduces panel space and wiring complexity. For complete fluid system monitoring, YM also offers Aviation Temperature Sensor GWR-1, Aviation Cold Air Solenoid Valve QDF-42A, and Hydraulic Filter MQL-5 – a one‑stop source for aircraft hydraulic and pneumatic systems.

How to Install & Use the GY-250 Aviation Pressure Contactor – Step by Step

1. Select correct pressure range and set point: Ensure the 0‑250 KGS range matches your system pressure. Determine the desired alarm or switching pressure (field adjustable via internal set screw).
2. Mounting: Install the pressure meter directly into a 1/4” NPT port (or MS flare fitting) using thread sealant (MIL‑PRF‑46010). Torque to 15‑20 Nm. Do not over‑tighten.
3. Electrical wiring: Connect the MS3112 connector: pin A = common, pin B = normally open (or pin C = normally closed depending on model). Use MIL‑spec wire (20‑22 AWG).
4. Set point adjustment: Apply system pressure and monitor with a calibrated reference gauge. Adjust the internal set screw (accessible via a sealed cover) until the contact switches at the desired pressure.
5. Functional test: Pressurize the system and verify that the contact closes at the set point (using a multimeter). De‑pressurize and verify contact opens.
6. Maintenance: Periodically verify accuracy against a traceable pressure standard. Clean the electrical connector with isopropyl alcohol. The internal sensor is maintenance‑free.

Pro tip for avionics integrators: For redundant monitoring, use two GY‑250 units with offset set points – one for caution warning and one for emergency shutdown. YM can provide pre‑set and sealed units for critical applications.

Application Scenarios & Key Buyer Benefits

Typical Military & Aerospace Uses

• Aircraft hydraulic systems: Landing gear retraction, brake pressure monitoring, and flight control actuator pressure – 250 KGS range covers typical 3000‑3600 psi systems.
• Drone hydraulic/pneumatic actuators: Payload deployment, landing gear, and weapon bay doors – lightweight and sealed for UAVs.
• Engine fuel & oil pressure monitoring: Over‑pressure alarm for fuel pumps and lubrication systems – contact output can trigger warning lights or engine control logic.
• Ground support equipment (GSE): Hydraulic test stands, pressure carts, and refueling trucks – rugged for field use.
• Train & industrial hydraulic systems: Brake pressure monitoring and press control – wide temperature range and vibration resistance.

Direct Value to International Buyers (Defense OEMs, MROs, System Integrators)

• Enhanced system safety: Integrated contactor provides real‑time pressure switching – eliminates separate pressure switches and reduces failure points.
• Reduced installation cost & space: Combines sensor and relay in one housing – saves panel space and wiring time.
• Lower lifecycle cost: Hermetic sealing and welded construction prevent leaks and contact corrosion – reduces field maintenance.
• Global compliance: MIL‑STD‑810G, MIL‑PRF‑39016, and AS9100D certified – ready for defense procurement and FMS.

For new aircraft or drone programs, YM offers custom pressure ranges, set points (factory preset), and electrical connectors. Engineering samples available for qualification testing.

Certifications & Compliance

• MIL-STD-810G (environmental – temperature, humidity, vibration, shock, salt fog, altitude).
• MIL-PRF-39016 (contact output relay section).
• RTCA/DO-160G (airborne equipment – Category A2, S, and R).
• AS9100D (aerospace quality management).
• RoHS & REACH compliant – full material declaration available.

Each GY‑250 pressure meter is 100% tested for pressure accuracy (0.5% F.S.), set point repeatability, contact resistance, dielectric strength, and hermeticity (helium leak test). Lot traceability per AS9100 is maintained. First Article Inspection (FAI) reports per AS9102 are provided upon request.

Customization Options

YM supports tailored GY‑250 variants for volume military and industrial orders. Customizations include:

• Pressure range: 0‑100 KGS, 0‑400 KGS, 0‑600 KGS (0‑6000 psi) – to match specific system pressures.
• Set point type: Fixed factory preset (non‑adjustable) or field adjustable (internal screw).
• Contact configuration: SPST‑NO, SPST‑NC, or SPDT (changeover).
• Pressure connection: NPT, MS flare, SAE ORFS, or custom manifold mount.
• Electrical termination: MS3112 (standard), EN2997 (fireproof), or pigtail leads.
• Output signal (optional): Analog 4‑20mA or 0‑5V in addition to contact output – for remote monitoring.

Our engineering team provides free feasibility analysis and 3D models for integration. Minimum order quantities for custom options apply – contact YM with your specification sheet.

Production Process & Quality Assurance (AS9100D Certified)

YM’s aviation instrument production line follows a zero‑defect, fully traceable process designed to meet the stringent demands of military and aerospace customers.

• Raw material control: 100% certification of stainless steel bar stock, pressure sensors, glass preforms, and contacts – traceable to mill test reports and batch certificates.
• Precision machining & welding: CNC turning of pressure port and housing; automatic welding of sensor element and diaphragm.
• Sensor calibration & compensation: Each sensor is temperature compensated (-55°C to +125°C) using a computer‑controlled test stand.
• Contact assembly & sealing: Relay contacts assembled in Class 100 cleanroom; glass‑to‑metal sealing of electrical feedthroughs.
• 100% functional test: Automated test system verifies pressure accuracy at 5 points, set point repeatability, contact resistance, dielectric strength, and insulation resistance.
• Environmental sample testing: Each lot undergoes thermal cycling (-55°C to +125°C, 20 cycles), vibration (20g RMS), and life cycle test (10⁵ pressure cycles).
• Final documentation: Calibration certificate, dimensional report, electrical test record, and C of C provided with each shipment.

With decades of experience in air pressure meter and hydraulic pressure sensor manufacturing, YM has supplied thousands of pressure instruments to global defense and commercial aviation customers. The GY‑250 is built to exceed the reliability expectations of modern aircraft hydraulic and pneumatic systems.