642 PROCEEDINGS OF SECTION H. 



7._NOTES ON A FEW EXPERIMENTS WITH GYROPLANES AND 



HYDROPLANES. 



Paper by GEO. HJGGJNS, M.C.E. {Melbourne Univ.), M. lust. C.E., M.Am. Soc. C.E., M. German 



Soc. Engineers, etc. 



So many lives have been lost within the last few months in con- 

 nection with the use of flying machines that it seems quite time 

 to enquire seriously whether it is not useless to continue working 

 on the lines hitherto followed. It appears that all that is necessary 

 to wreck any aeroplane is that a sufficiently strong gust of wind 

 shall be encountered. If an aeroplane is to be safe from the 

 effects of gusts of wind, which may have a velocity of 60 miles 

 an hour, the aeroplane must be able to travel at a speed still 

 higher than 60 miles an hour. And if this is so, what is to happen 

 if a gust strikes an aeroplane before it attains that speed at 

 starting, or while it is slowing down to effect a landing ? 



It seems almost certain that no mere modification of the 

 present type of aeroplanes will avoid more than a fraction of the 

 great risk which is met with. It seems almost certain, too, that 

 unless some substitute is found for the aeroplane the use of the 

 heavier-than-air machine will have to be abandoned. 



It is desirable, therefore, that any invention which has for its 

 object the substitution of some body less liable to be " driven with 

 the wind and tossed " than the curved or flat-plate now so much 

 used should be carefully looked into. 



One scheme, having this for its object, has recently been brought 

 under the writer's notice. The suggestion is that of Ernest 

 Sadleir, of Boulder, W.A. He made some four-armed boomerangs, 

 which he called " gyroplanes," the under-surfaces of which were 

 flat, and in one plane. These he found to behave very much as 

 the boomerangs do which are used by the aborigines, and their 

 wonderful steadiness, in spite of gusts of wind, impressed him. 

 He tried the effect of adding weights of varying heaviness to 

 them, until he reached a limit, beyond which his gyroplanes would 

 not rise when thrown. The idea that his gyroplanes would be 

 much steadier in the air than the curved or flat plates called 

 " aeroplanes " has long been present with him. He aims at trying 

 whether rotating gyroplanes will not answer better than plates, 

 curved or flat, when the gyroplanes are set at the necessary up- 

 ward inclination and suitably propelled — i.e., the whole gyroplane 

 is given the inclination, but the arms have their undersides in 

 one plane, and any number of gyroplanes can be attached to one 

 machine. 



To ascertain whether or not this contrivance is likely to be 

 successful practically it is necessary to determine two things — (1) 

 whether or not a rotating gyroplane is capable of sustaining as 

 great a weight as a disc whose diameter is the same as that of the 

 gyroplane ; and (2) whether the gyroplane will remain sufficiently 

 steady in gusts of wind to avoid being wrecked by them. The 



