DIGITAL 24-CHANNEL ‘HYDRA’ RAKE
Versatile integrated digital rake system for simultaneous velocity measurement
Based on our MUS-series ultraminiature sensing technology, this fully self-contained, 24-channel rake system provides a highly compact and configurable solution for multipoint flow measurement applications. With a variety of interchangeable sting configurations ranging from 3x 7-hole ‘Hydra’ rakes to omni-probes – and a custom sting design service available – this versatile system provides cost-efficient, high quality measurements for demanding, high-productivity test environments.
In addition to its 24 independent, true-differential pressure measurements, this probe also provides absolute static pressure, local fluid temperature and humidity (for density corrections) and an IMU for automatic alignment and vibration warning. A low-profile, in-line sensor package (measuring 20 mm in diameter) minimizes interference. Fully-generalized data processing software is also included to convert pressures from any configuration of individual probe heads into three components of velocity.
Applications
Digital 24-channel ‘Hydra’ rake

Wind tunnel testing
With 24-channel, 24-bit pressure measurements, integrated environmental and alignment sensors, this rake system is one of the most versatile and sophisticated fluid velocity measurement tools on the market. With ranges of 6.9 kPa and an integrated fluid temperature sensor, this system is ideal for measurements at speeds up to 110 m/s.

Motorsport
With optional CAN and Ethernet communications modules, this system offers a complete high-performance, high-precision solution for demanding wind-tunnel test schedules. Tight fabrication tolerances and factory sensor calibration also allows a degree of probe interchangability, minimizing down-time and the need for time-consuming recalibrations.

Industrial testing
With configurable, bespole rake geometries and a wide variety of probe configurations, this system can significantly reduce costly wind tunnel testing time and provide simultaneous multi-point measurements in complex, three-dimensional flow environments.
FEATURES
Product Details
Data sheets and user manuals
- Data sheet – Surrey Sensors DS-MD24HP-251125-1.0
- User Manual – Surrey Sensors USM-MD24HP-251125-1.0
Technical notes, application notes and references
- Uncertainty in pressure-based velocity probes – TN-0614-2017
- Multi-hole pressure probes – TN-0616-2016
- Generalized calibration of multihole velocity probes (external link)
- Optimal calibration of directional velocity probes (external link)
- Compensating low-range pressure sensors for vibration error (external link)
Downloads available
USB Driver:
Software (USB):
- Surrey Sensors Ltd. MD24HP USB user interface v1.0
- NI LabVIEW VI development kit for MD24HP USB v1.0
- CRC-16 Checksum implementation tools
Software (Ethernet):
Ethernet communications require an additional communications adaptor.
- Surrey Sensors Ltd. MD24HP Ethernet user interface v1.0
- NI LabVIEW VI development kit for MD24HP Ethernet v1.0
- CRC-16 Checksum implementation tools
Third-party drivers (required):
- National Instruments LabVIEW (select “run time engine” only, 64-bit version)
- National Instruments NI-VISA
End-user licence agreements:
















