Risk factors. Factors that increase the risk of stuttering include: 1  Having relatives who stutter. 2  Stuttering tends to run in families. 3  Delayed childhood development. 4  Children who have developmental delays or other speech problems may be more likely to stutter. 5  Being male. 6  Males are much more likely to stutter than females are. 7  Stress.
The average speed for a four-seat helicopter is 130 to 145 miles per hour. Because smaller helicopters have smaller engines, the average speed for a two-seat is 90 to 105 mph. The fastest helicopter on Earth as of 2014, the X3 Eurocopter, can fly at 300 mph. Keep Learning.
hi guys i am looking to buy a helicopter so i hope someone can tell me what is the longest range and fastest speed a helicopter can do i was just browsing some site and read that a very old bell about 21 years old was able to do speeds of 250kmh and a range of between 325 miles and 410 miles with extra fuel tanks now this really blows me away and that was back 21 years ago so i wonder what kind of technology has gone into the helicopters now