◆ SpookStack

telegraph communications. It included a ort-Wwive abd a iong-wave transmitter, each with 200-watt antenna capacity; two all-wave receivers and two direction Snders. The frequeucy of the short waye trans- maicter was 4160. tg 17500 kilocycles, The frequency of the long wave transmitter wae 120 to 600 kilocycles. The frequency range of the receivers was 12 to 20000 kilocycies. Power for the transmitters was obtained from a 220-volt direct current supply gen- erated by the ship's electric power Plant. The receivers obtained their high voltage from batteries, and power for their filaments was obtained through a series resistor from the 24-volt ship's generator. For the short wave transmitter, there was a trailing an: tenpa of 26 meters length, Kor the loug- wave transmitter, a trailing antenna of about #0 meters length was uged. These trailing antennas were located | rectly be- jow the transmitters and ram throu an aperture in the Heel of the ship. here was a fixed antenna extending from the contro] car about 15 meters toward the stern, The fixed antenna was used only for receiving purposes, In addition to thix equipment, there was Iocated in the bow un emergency transmitter and receiver, cur- rent for which was obtained from a gen- erator driven by pedal power. This emer- goney set employed a trailing antenna about meters in length. Lifting Gas The ship was inflated with hydrogen. According to the evidence adduced, this eas bas the following characteristics: It ix colorless, odorless, and tends to diffuse in all directions, The only way that hydrogen could be detected by smell would be due ta the presence of impurities as a result of the process by which It was produced, or contamination from some source such as rubberized fabric. Hydrogen, for lifting purposes, bes a density of approximately 5 Bounds per 1,000 cuble feet, depending on the temperature and pressure. Its lifting power is the difference between the density of air and fta own density. The density of alr ia about 75 pounds per 1,000 cubie feet. Assuming pure hydrogen, its lifting power would therefore be about 70 pounds per 1,000 cubic feet. An opinion was ad- vanced that the general order of pressure of the gas within the cells of the ship was somewhere between half an inch and i inch of water pressure, It was stited that the density of hydrogen corresponds to air at a temperature of 5,000° F. and that the chimney effect of its escape through the Fas shafts of the ship was go very great that there was no possibility of its moving down the shafts into the lower parts of the ship. The fammable Mmits of a mixture of hydrogen and air are probably between 4.5 percent and 62 percent of bydrogen. Other experiments have shown veriances from 8-9.8 percent to 68 percent. The tem- perature ot which chemical activity be- tween hydrogen and oxygen takes place is between 507° to 557° C. This temper. ature range ig dependent upon the amount of hydrogen present. The range of ac- tivity ef combustion will be from the lower limit of 4.5 pereent at which there will probably be an invisible union without evi- dence of flame. A combustible mixture would be more hazardous in an atmospheric condition of ®8 percent relative humidity, and temperature 60° F. than in dry air with relatively low humidity, since dry hydro-oxygen ig more difficult to {gnite and its ignition temperature ig higher. In an erplosion the flame propagates in all direc- tions in the combustible range between 15 to 45 percent of hydrogen. These . = ’ AIR COMMEECE BULLETIN J 25 figures were arrived at experiinentallp with gluas or inetallic apparatus which did not have effect upon the combustion tempt. atures. Catalytic metals having adsorption propertica woud. ve Hkely to affect the com- bustion at lower Temperatures, Finished dorainmin would not be expected to have material catalytic effect upon hydrogen. Bounding The whole metallic structure of the craft was bonded. Part Ill—The Landing Maneuver Meteorological Conditions With respect to the meteorological con- ditions fn which the Junding was conducted, a summary of ihe general weather 1s given ag well as the Jocul conditiuus prevailing at Lakchurst at the time of the accident. GENERAL The 7:50 a.m, E. 8. T. United States Weather Bureau) may of the vicinity, in- cluding the northeastern tier of Staies, shows a disturbance over ceniral New York and northeastern Pennsylvania, with a cold front extending frum this center southwestward to West Virginia, This front separated neutralized polur vir tu tle east of the cold front which had become warmer and more Moist and neutralized colder wir to the west of the front. The warmer atid more moist miss of air covered the Middle Atlantic States, southedstern New York, aud southern New England. The cold front advanced enstward during the day from central Pennsylvanin ut a rate of 12 to 15 miles per hour, passing Lakehurst shortly after 3:30 p.m.) There was not quite sufficient surface beac during the early afternoon to set of a thundersturm at Lakehurst, and it was not until the front passed and some slivht lirs- ing of the air mass occurred that a thunder- storm began. The records of the naval air station show that the thunderstorm begau at 3:40 p.m. and ended at 4:45 p. m. Telegraphic reports indicate, the thuuder- storms in and to the west of New Jersey Were not severe; nor were they cf a well-ile- fined squall character. Between 12 p. m. and 1:30 p.m. E. 8, T., these storms ex- yended in a definite belt over the region of Harrisburg, Pa, northeastward toe Bear Mountain, N. Y., and New Hackensack, N. ¥. Between 1:30 and 2:40 p. m. none was re. ported. Between 2:40 and 3:40 P: m.. Cam- den and Fort Monmouth, N. J., onfy, reported thunderstorms. Between 3:36 and 4: 80 p. m., Lakehurst, Mitchel Field, N. ¥.. and Floyd Bennett Field, N, Y¥., reported them. Between 4:40 and 5:40 p. m, nene was reported ; und between 5:40 and 6:40 p. m., Floyd Bennett only reported one. Sune marized. the thunderstorms in eastern New Jersey were of a local character and not severe. The New York Weather Bureau offie: bulletin issued at 1:20 p.m. May 6, fol- OWS : “1800 G. C. T. Moderate wind shift with focrensing and Jowering clouds possible tbundershowers New York and vicinity ex- ected in middle or late afternoon Stop ew York scattered cumulus and = smalt cumulo nimbus approaching from west -— visibility excellent surface wind sonth 12 miles—barometer 29,68 falling steadity-— temperature 66." LOCAL With the passage of the front at Lake- burst, the wind shifted to the werlbwest with gusts up to 20 Enots, and was aec- ask Lag teem tn a Peto