Flying Machine Book: Build and Launch 35 Rockets, Gliders, Helicopters, Boomerangs, and More

Flying Machine Book: Build and Launch 35 Rockets, Gliders, Helicopters, Boomerangs, and More — page 9
2 K O O B E N I H C A M G N I Y L F E H T Of course the Wright brothers pioneered powered flight but Cayley’s work is more closely related to the flying machines you will be building Each chapter in this book focuses on one type of flyer helicopters rockets boomer angs and different types of gliders Not all the flyers are easy to make and many take practice to perfect But with a little patience your flyer can reach the sky The Bernoulli Principle Daniel Bernoulli’s dad a brilliant mathematician never wanted his son to study math Instead he wanted Daniel to study medicine because it paid better Daniel did go into medicine but never forgot his love of math As a math professor in his 20s he discovered a principle that combined his interests in math science and medicine and it made him both famous and rich At the time of his discovery Bernoulli was working with blood He wanted to know about the relationship between blood pressure inside an artery and the speed of the blood through the artery He soon realized that if he punctured a tube carrying a fluid with a thin pipe the fluid would go up the pipe And more interestingly how far it rose due to pressure was related to the speed of the fluid past the end of the pipe For the next 150 years in Europe physicians would measure blood pressure by piercing a patient’s artery with a thin glass tube Luckily for you and me we have a safer way to measure blood pres sure today Even though Bernoulli was working with a liquid the same principle works for gases such as air Scientists classify both liquids and gases as fluids since they flow You can see Bernoulli’s principle at work by doing this simple experiment Hold a long strip of paper a dollar bill works well tucked tightly just under your bottom lip Blow hard directly outward and the strip will rise Fast-moving air creates a low pressure above the paper and the strip lifts Now let’s put Bernoulli’s principle to work and learn more about the science of flight Four Forces Flight is governed by four forces lift thrust drag and weight