Significant progress has been made on the development of a electrically powered glider by the SIO / WHOI (with a subcontract to Webb Research ) consortium during the first year of the MURIP. However, we have not been able to meet our planned schedule due to the serial nature of the initial development that required the design and construction of the initial prototype before the final design and integration of the controller, communications antennas, and sensors could be completed.
A prototype of glider was delivered by Webb Research to SIO in September for integration with a controller and for tank testing. The controller, including the software to manipulate the flight attitude controller and hydraulic pump, is now working. This prototype, consisting of a hull with rails to mount wing at variable locations near the mid-length of the hull, buoyancy changer, mechanical components of the flight attitude controller, relocation pinger, and emergency jettison weight, is now undergoing bench tests and static tank tests at SIO. A second prototype is to be delivered to WHOI in the near future.
Experience gained in both the production of the prototype and the first bench tests has identified several features of the design that are now being revised. Preliminary tank tests at SIO have evaluated the static performance of the vehicle and documented its basic parameters, such as center of gravity and buoyancy and the ability of the attitude control system to change these parameters. Although some deficiencies have been identified, we still believe that the prototype can be modified so that preliminary lake and at sea tests can be carried out before going through a complete redesign. A full review of the prototype design will be undertaken in early January after the initial bench and tank tests are completed.
An evaluation of the performance of the ORBCOMM satellite communications system was not started until September because the availability of the Beta-test versions of the terminal was delayed by six months. WHOI now has two units from Torrey Systems in hand and has successfully transmitted data through the system. The preliminary results suggest that the system should be able to deliver the data from the glider to a workstation on our desk in the form of an email message, including standard data compression schemes, such as uuencode. A low power, GPS receiver from Garmin has been purchased and is now being evaluated. Bench tests of these communications and positioning sub-components will evaluate how robust they are when the glider is in the surface wave field. Preliminary designs for the two antennas, located in one of the wings are now being finalized. Local tests of the communications and positioning components using a simple hull will be carried out during the first quarter of 1997.