nis(:ovi:HY 



95 



RIGID AIRSHIP R23 LliAVIXG SHED I'OR TRIAL IXIGHT. 



It is conceivable that, if the shed at Howden had 

 been equipped with similar rails, Rj4 might have been 

 housed without accident. 



The difficulties attendant on taking airships in and 

 out of sheds in any but favourable weather conditions 

 are so great as to render this type of aircraft practically 

 useless for commercial purposes, where a reasonable 

 regularity of flying is essential, unless some means of 

 overcoming them is assured. The solution of this 

 problem is undoubtedly mooring in the open. 



Since the earh' days of airship history, experiments 

 have been conducted in mooring out as an emergency 

 method in the event of mechanical breakdown pre- 

 venting an airship from returning to her base. These 

 e.xperiments have throughout followed two lines of 

 thought — (i) mooring by means of cables ; (2) mooring 

 to a mast. 



With regard to the former of these two methods, 

 in the early days trials were made in mooring to a 

 drogue by a single cable over water. The dragging 

 motion of the drogue through the water was found to 

 check to a great extent any tendency of the bow of the 



ship to move in a lateral direction. When moored, 

 however, to a single point on land, it was found almost 

 impossible to keep the airship head to wind. To 

 correct this tendency to surge, the method was 

 amplified by introducing three cables, which were 

 led to the mooring-point of the ship. This 

 system, known in its earlier stages as the " Usborne 

 Method," from the name of its originator, has been 

 developed into the present-day three-wire system, 

 which was utilised with unfortunate results in the 

 case of R34. 



In this system three bollards are spaced at a con- 

 siderable distance apart, and form in plan an equilateral 

 triangle. To these are attached the three mooring 

 cables taken up by the lift of the ship, which floats in 

 the air at the apex of the pyramid so formed. When 

 trimmed up by the bow, the airship will be found to 

 ride satisfactorily, although there is always a tendency 

 to " yaw." The disadvantages of the method are 

 the difficulty of replenishing gas in rough weather, 

 and the danger aforementioned of the ship getting 

 off the wind. For these reasons, mooring by cables can 



