Fig. 167.—Sections of Hydroplane Floats
Calculating Capacity of Hydroplane Floats.—The floats of a model hydroplane must be made sufficiently large to displace about three times the model’s weight of water, since it is necessary that they should be only one-third immersed. A cubic foot of water weighs 1,000 oz. approximately. Then
| 1728 | 8 | ||
| —— | × | — | = 13·8 cub. in. |
| 1000 | 1 |
must be displaced to float 8 oz. Multiplying this by three gives 42 cub. in. as the total cubic capacity of the floats. Two front floats, each 5 in. by 2 in. by 1 in. maximum depth, and a rear float 8 in. by 3 in. by 1 in. would be about the correct size to use. A slightly larger diameter and pitched propeller would be necessary on a hydroplane to develop more thrust to overcome the resistance of the floats. Some well-known hydroplane sections are given in [Fig. 167].
Showing Marking of Block
Finished Screw of Truly
Helical Formation
Setting out the Angles