ASH IP has recently been devised 

 which carries a veritable gale pent 

 up, not in an oxskin, such as Homer's 

 Odysseus used to carry away the winds 

 from the isle of Mo\us, but in a cylindrical 

 tank. This boat was designed primarily 

 as a toy, a bicycle pump being used to fill 

 the tank. With one pumping, 16-in. models 

 have a cruising radius of about ioo yd. 

 and run from Yl to 10 minutes, depending 

 upon the rate of escapement of the air. 



In the course of experiments with air 

 propulsion it was found that a simple jet 

 of air, allowed to escape from a boat, is 

 very ineffective. Placed in a semi-circular 

 tunnel the jet be- ftrrK 



comes doubly effi- 

 cient. Still greater 

 saving of power is 

 made by leading the 

 spent bubbles up in 

 an incline at the 

 stern to the surface, 

 as shown in Fig. I. 

 Thus the lifting 

 power of the bubbles 

 is used in propelling 

 the boat, or it might 

 be said that the boat is continually coasting 

 down a row of bubble rollers. 



Making an Air Torpedo 



Perhaps the most simple form of an air 

 boat, as a toy or for experimental work, is 

 the torpedo, in which an air chamber forms 

 a greater part of the boat-body. This air 

 chamber, as shown in Fig. 2, is a 2-in. 

 cylinder with semi-spherical ends, into one 

 of which a bicycle tire air-valve is fitted. 

 To this end a stern piece, containing a 



bubble-way, Fig. 3, is soldered. With the 

 air-pipe and nozzle, Fig. 4, in place, and 

 with the tank tested airtight, the torpedo 

 is ready for use. The speed depends en- 

 tirely on the size of the jet aperture. This 

 can best be regulated with a pair of pliers. 

 Since speed is desired, it should be adjusted 

 to exhaust the air supply in 20 to 30 

 seconds. 



How to Make a Submarine Chaser 



In the illustration, Fig. 5, there is shown 

 one of the most interesting toys of 

 today, the submarine chaser. It is a 

 V-bottom boat, all metal, war gray, 

 with an automobile-type steering 

 gear that really moves the rudder. 

 It is 16 in. over all, 

 with a 43^-in. beam, 

 and runs from 5 to 

 12 minutes at a fair 

 speed . Any boy who 

 has a soldering set 

 and tinsnips can 

 build it at small 



Fig. 1. The compressed air is allowed to 

 escape in a semi-circular tunnel at the stern 



expense. 



The hull with the 



extension of the 

 stern-plate is cut from a single piece of sheet 

 tin, Fig. 6. This metal is bent on the 

 lines A, B, and C to form the keel and 

 sides. With three angle strips to reinforce 

 it, the bow is soldered together as in Fig. 7. 

 The stern-plate is next fitted on. Now it 

 is ready for the tank. This is made of two 

 circular cans, in the larger of which an air- 

 valve is placed before the two are joined, 

 to form a cylinder 8 in. long and 2^ in. in 

 diameter. This is shown in Fig. 8. The 

 ends of the tank are strengthened by a wire 



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