Landyacht Performance Prediction

These charts show the predicted performance for a notional rigid winged landyacht. It conforms to the US Class IV open class rules. The wing section had a 30% chord slotted flap, and the main wing section was custom designed to provide high lift at low Reynolds numbers in conjunction with the flap.

These results were calculated with a more sophisticated model than the simple MathCad model, but the basic relationships are the same. The principal difference was the use of tabular aerodynamic section data rather than the parabolic drag polar used in the MathCad model.

GW	Gross Weight	400 lb
theta	Angle Between Mast and Rear Wheel	15 deg
diam	Wheel Diameter	3 ft
S	Sail Area	59 ft^2
height	Mast Height	25 ft
AR	Aspect Ratio	10.59322
L		32.64775 ft
axle	Width of Rear Axle	11.47103 ft
mu	Tire Friction Coefficient	0.6
cbar	Mean Wing Chord	0.903584 ft
e	Oswald Efficiency Factor	0.9
CDbod	Parasite Drag Coefficient for Chassis	0.15
Ki	Induced Drag Factor	0.033387
epsilonw	Angle Between Centerline, Front Wheel, and Rear Wheel	0.463648 rad
Hce	Height of Center of Effort	14.25 ft
Ycg	Lateral Location of Center of Gravity (to line between front and rear wheel)	8.55 ft
Xcg	Longitudinal Location of Center of Gravity (from front wheel)	19.11838 ft
Xaxle	Distance Between Front Wheel and Rear Axle	22.94206 ft
Dw0	Rolling Resistance Coefficient	0.02
Xce	Longitudinal Location of Center of Effort	19.11838 ft
Dwv_125	Rolling Resistance Speed Factor	0

Boat Speed Polar

Peak Speed

Specific Excess Thrust

Section Drag Polar

Section Lift Curve

Section Drag Curve

Cornering Tire Model

Last Updated on 1/16/99
By Thomas E. Speer
Email: tspeer@gte.net

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