Figure 10 shows the result during 60 seconds at the oval course running in left turn. In this case, after 15 seconds, the rudder angle keeps almost constant around 3 degrees. On the other hand, the crew inclines right and left considerably. Therefore, it can be considered that the oval course running was accomplished by not the rudder control but the lateral movement of the crew. The simulated roll angle in (b) shows fairly good agreement with the measured one. In Figure (c), although the last part of simulated trajectory deviates from the measured course, during the first one around, the simulated trajectory shows good tendency of the oval course. From these results, it can be considered that the numerical simulation indicates the rolling stability and control capability of this boat very well.

　

 We focused on the rolling stability and control capability of a very small hydrofoil craft, which has no automatic control system in rolling motion. The crew maintains lateral stability by controlling rudder angle and shifting his weight in the cockpit just as controlling a bicycle. In the measurement we clarified the motion of the boat according to the variation of rudder angle and crew incline angle. This revealed the control mechanism of this hydrofoil configuration. In the numerical simulation, we established the four simultaneous differential equations and the simulated results coincided well with the measured data. Therefore this simulation method can be used to clarify the lateral stability mechanism of such small hydrofoil crafts.

　

[1] Masuyama, Y., Tsukamoto, Y. et al.: "Design, Development, and Construction of A Solar Boat at The Kanazawa Institute of Technology," Solar Engineering, ASME, pp. 215-227, 1996

[2] Masuyama, Y., Ito, M. et at. "Improvement of The '96 Solar Boat at The Kanazawa Institute of Technology," Solar Engineering, ASME, pp. 349-355, 1997

[3] Masuyama, Y., Wada, H. et al.: "Development of A Propeller Open Test System and An Advanced Maximum Power Point Trucker (MPPT) for Solar Powered Racing Boat," ASES and ASME Conference, pp. 483-487, 1998

[4] Horiuchi, K.: "Locus of A Boat Designer," Kazi Publication, 1987 (in Japanese)

[5] Terao, Y.: "A Study on The Simulation of The Motion of Personal Full-submerged Hydrofoil Craft," Journal of The Society of Naval Architects of Japan, No.184, 1998 (in Japanese)

[6] Cane, P. D.: "High-Speed Small Craft," David & Charles, pp. 33-41, 1974

[7] Wadlin, K. L., et al.: "A Theoretical and Experimental Investigation of the Lift and Drag Characteristics of Hydrofoils at Subcritical and Supercritical Speeds," N.A.C.A. Report 1232, 1955

[8] Vladimirov, A. N.: "Approximate Hydrodynamic Design of A Finite Span Hydrofoil," C.A.H.I., 1937, translated as N.A.C.A. Technical Memorandum 1341, 1955

[9] Masuyama, Y.; "Hydrodynamic Forces Acting on The Hydrofoils for A Hydrofoil Sailing Boat," Journal of The Kansai Society of Naval Architects, Japan, No.187, 1982 (in Japanese)

[10] Masuyama, Y.: "Motion of A Hydrofoil System in Waves," Journal of The Kansai Society of Naval Architects, Japan, No.196, 1985 (in Japanese)

[11] Hoerner, S. F.: "Fluid-Dynamic Drag," Hoerner Fluid Dynamics, 1958

　

Yutaka Masuyama

 Professor, Dept of Mechanical Engineering, Kanazawa Institute of Technology. Yutaka Masuyama, who is now fifty-six, graduated from the Dept. of Mechanical Engineering of the graduate school of Toyama University in 1971. He worked as an apprentice at the Kumazawa Craft Laboratory, yacht design office, from 1972 to 1975. From 1975, he has been working at Kanazawa Institute of Technology. His main field is fluid dynamics and naval architecture, in particular sailing science. He has been studying about the sailing performance of a hydrofoil sailing boat to the America's Cup boat. He is also interested in the performance of small water vehicle such as a hydrofoil solar boat.

　

Yasuhide Ohno

 Nachi-Fujikoshi Corp. Yasuhide Ohno, who is now twenty-six, graduated from the Dept. of Mechanical Engineering of the graduate school of Kanazawa Institute of Technology in 2002. He studied the rolling motion and maneuverability of the small hydrofoil craft as his master's research. He drove the hydrofoil craft by himself He is now working at the Nachi-Fujikoshi Corp.

　

Tomohiko Ogihara

 Graduate school of Kanazawa Institute of Technology. Tomohiko Ogihara, who is now twenty-five and a student, is studying the rolling motion and maneuverability of the small hydrofoil craft as his master's research. He had been an exchange student at Rochester Institute of Technology in the U.S. from 2001 to 2002.