On the other hand , a 5,000,000 cu. ft. airship flying at 60 mph experiences only about 20 lbs. resistance per 1,000 lbs lift .
The relative resistance decreases with increasing size and diminishing speed .
On the other hand , a 5,000,000 cu. ft. airship flying at 60 mph experiences only about 20 lbs. resistance per 1,000 lbs lift , and the relative resistance decreases with increasing size and diminishing speed .