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CIRPAS Twin Otter
Scheduled typically 4-12 months in advance.
Request form on CIRPAS website: www.cirpas.org and on the Unals web site: www.unols.org.
Airborne Platforms
Twin engine, non-pressurized turboprop airplane, De Havilland model DHC-6-200.
Haflidi H Jonsson
CIRPAS/Naval Postgraduate School
3200 Injin Road, Hangar 507 Marina, CA 93933
(831)-384-2776 x11
Aircraft TypeDe Havilland DHC-6-200, Twin Otter
PayloadCapacity with full fuel tanks is 1500 lbs
Range750 nm with full fuel tanks
Ceiling18,000 feet (practical)
Endurance5 hrs
Capabilityrestricted to non-icing conditions
Airspeed Range100 - 150 kts
Runway RequirementsAbsolute minimum runway length is 2000 feet.
Max Takeoff Weight13,500 lbs
Max Fuel Weight3,100 lbs
Flight CrewPilot and co-pilot.
Number of SeatsNot specified, but weight of science crew counts toward the 1500 lbs capacity
Airworthiness CertificateNavair certified.
Typical UsesResearch
Data SystemNational Instruments hardware, Labview based software. Analog acquisition at 100 hz synchronized to GPS clock, as well as a synchronizing time stamp that is merged into digital data streams from 'smart' instruments. Data are streamed to ground in real time via Satcom to minimize need for on-board scientists or payload operators.
Special Field Support NeedsThe CIRPAS hangar in Marina is fully equipped for aircraft maintenance, payload integration, instrument maintenance and calibration. All necessary equipment is generally deployed with the aircraft. Payload may be powered up under ground power and prepared prior to launch and without interuption switched to aircraft power after engine start. Air conditioning is available for ground operation on the aircraft. Facility data are generally reduced in the field and immediately after flight made available to science team members.
Research Power200 ampere of 28V DC (5600W) are available for payload. Off that up to 4000W may be inverted to 110V AC.
Cabin EnvironmentBleed air heating is available, but no cooling while in the air.
Rack Space AvailableStandard 19" racks are available. They are 42" high and 24" deep. Six such racks may be placed in the cabin, and a fractional one in the aft luggage compartment.
Available InletsOne, well characterized community inlet is available. It captures the air sample before the plane starts bending flowlines. It brings 400-500 LPM into the cabin where sample may be drawn off it to various instruments. Its particle transmissivity has been carefully characterized and it determined that its transmission efficiency is 100% for 3.5 micrometer diameter particles, 50% for 5 micron particles and small for particles larger than 7 microns.
Available AperturesBelly: About 21" diameter hatch. Roof: Elongated, 24" transverse, 12"fore-aft hatch. These may be populated with sensors. Additionally there are three about 2" diameter down looking ports and one up looking.
Available Hard PointsTwo hard points on each wing for pylons and pods. A hardened plate is on the top of the fuselage, forward of antennas and other obstructions to full hemispherical view.
External PodsEach of the four hardpoins on the wings can be rigged with a pylon. The pylons have PMS footprint. Footprint multipliers permit up to three pods (typically cloud probes) on each pylon. It is alos possible to suspend utility pods (with or without inlets) on the pylons. Available pods are 18" in diameter and 24" long. Guest investigators frequently use some of the pylons.
Standard InstrumentsCIRPAS lists its available instruments on its request form. There are two groups of instrument there: 1) Facility instruments, operated and maintained by the facility, and 2) Research (complex) instruments owned by CIRPAS, but operated and mentored by experts from other institutions. Amongst facility instruments are: Meteorological sensors: Total Temperature, Dewpoint, Static Pressure, Dynamic Pressure, Attack angle, Slip angle, and Sea Surface Temperature. Navigational parameters: Latitude, Longitude, GPS Altitude, Radar Altitude, Pitch, Roll, Heading, Ground Speed, and Ground track. Calculated Meteorological properties from these measurements are: Ambient temperature, relative humidity, specific humidity, wind speed, wind direction, vertical wind velocity, pressure altitude, and potential temperature. Aerosol Properties: CN counters (TSI 3010), Ultrafine CN counters (TSI 3025), DMT Dual column CCN, size distributions (Passive Cavity Aerosol Spectrometer Probe-PCASP-, and Cloud Aerosol and Precipitation Spectrometer-CAPS), Total scatter coefficient (TSI 3 color nephelometer), Absorption coefficient (3 color Radiance Inc. PSAP, DMT's PASS-3). Cloud and precipitation particle size distribution: (Forward Scatter Particle Spectrometer - FSSP_100, PMS, Inc., Cloud Aerosol Precipitation Spectrometer - CAPS, DMT, Inc., Standalone 2-D Imaging probe - CIP, DMT Inc.). The research instruments include, a turbulence flux suite of instruments, a 95 Ghz cloud radar, a wind lidar, an Aerosol mass spectrometer, stabilized platform for radiometers and more. Please consult the request form for details.
Training Requirements1 Hr safety briefing
CommunicationsSatCom, VHF radio, HF Radio
Available InstrumentsAs weigh, power, and space capacity permits, guest instruments or other required instruments may be integrated into the aircraft's payload.
Other SystemsAn instrumented towed body and a pod-mounted sonde/chaff dispenser have been certified to fly.
User SupportMaintenance staff assists with mechanical and electrical integration of guest instruments. Whne operating from the CIRPAS hangar in Marina, CA, office space with internet connections, laboratory space for instrument sercice, and meeting rooms for flight planning or science team meeting are provided.
Bane, J. M., R. Bluth, C. H. Flagg, C. A. Friehe, H. H. Jonsson, K. Melville, M. Prince, and D. Riemer, Research Aircraft Facilities for U.S. Ocean Sciences, 2004, Oceanography, 17, 176-185. Bluth, et. al, 1996, Center for Interdiciplinary Remotely Piloted Aircraft Studies (CIRPAS), Bull. Am. Meteorol. Soc., 77, 2691-2699.
The aircraft is generally scheduled on first-come first-serve basis.
22 Sep 2009 11:52