The science and art behind the design of airplane propellers started simply. The basis for the airplane propeller design’s original concept was the same as the concept behind the screw. That’s right, the simple screw.
Of course, this screw design was well before different repair shops could handle repairing and replacing various parts for all aircraft sizes. For today’s aircraft propeller repairs, contact Stockton Propeller.
Back In The BCs
According to most aerospace history experts, Archytas of Tarentum is responsible for the invention of the screw. He lived from 428 BC to 350 BC.
This invention was adopted quickly by the ancient Greek scientist Archimedes in 200 BC.
The first screws were used to extract oils from olives and juice and move water up from wells with less effort. We know for sure that this was a commonplace technology used from Egypt to Greece and beyond.
A “Little” Later On
Leonardo DaVinci, the great artist and inventor, sketched his first “flying machine,” or helicopter design in the mid-1400s.
He never built this first helicopter or flying machine. But sketches of the design included an upward-facing “airscrew” that he believed would lift the machine off the ground with enough rotation.
The 1700s and 1800s Starred Major Developments
Yet it wasn’t until the mid-1700s that inventors began discussing how to use this technology to power boats by creating rotating screws, or boat propellers, to power vehicles through the water.
By the 1800s, boat propellers had become the standard technology for a wide variety of marine vessels.
In the 1840s, Sir George Cayley designed a flying machine. His design included twin propellers.
Another early pioneer was Alberto Santos Dumont, who designed his own propellers for his airships. He used aluminum for his propeller designs.
The 1900s Took Over
However, the Wright Brothers would take the airplane propeller’s idea from paper to practicality in 1903. They introduced their twisted airfoil propeller design. The Wright Brothers threw out the old notion that airplane propellers’ design should be based on screws. They hypothesized that the design of an airplane propeller should look more like a wing than a screw. After all, wings create the lift that buoys the airplane. Airplane propellers, they reasoned, should be able to displace air backward to produce forward thrust. This reasoning led them to add a twist along the blade’s length. The twist ensured a more consistent angle of attack for the blade. The twist allowed for pulling a consistent amount of air toward the plane with each rotation.
Until the mid-1920s, propellers were made from wood and were fixed pitch, which significantly limited the aircraft’s performance capabilities. Wood propellers turned the aircraft engine’s power into thrust to propel the plane forward. They featured a permanently set blade angle, called fixed-pitch, and consisted of layers of wood. They were cheap, easy to manufacture, and light, and were the dominant propeller type for high-performance aircraft until the mid-1920s. After that, small general aviation aircraft relied upon them for thrust. The Vin Fiz, T-2, Douglas World Cruiser Chicago, and the Piper Cub feature wood propellers.
In 1929, Wallace Turnbull patented his original design for a variable pitch propeller. This new design allowed the pilot to manually adjust the blades’ pitch and maintain better control over the aircraft’s performance and operational efficiency.
In the 1940s, wide rectangular blades came into use as engine power increased, as they absorbed more energy than traditional round-tip blades.
Later, engineers developed constant-speed propellers. Constant-speed propellers are variable-pitch propellers. They adjust pitch automatically to maintain a constant rotational speed easily. Many of today’s high-performance propeller airplanes use constant-speed props because they offer better performance and fuel efficiency.
Fast Forward To Today’s Aircraft Propellers & Repairs
Aviation has come an incredibly long way since the Wright Brothers first introduced their propeller design. Just as airplane design has progressed since the beginning of powered flight, aircraft propellers have transformed, too. The Wright Brothers’ newly-designed propellers were about 82% efficient compared to today’s 90% efficiency rate. To achieve those gains in efficiency, engineers have modified airplane propeller designs over the years.
Today’s aircraft propellers are made from wood, aluminum, or composites. Designers may also reinforce the leading edge with nickel for strength and durability.
Today, we see anywhere from two blades to six or more blades for propellers in operation. The blade count for any particular aircraft depends on many factors. These factors include:
- the engine power,
- the operating RPM for the propeller,
- the propeller’s diameter limitations,
- that aircraft’s performance requirements (including high-speed cruise, takeoff, loiter, etc.),
- any noise requirements,
- and various others.
As an aircraft’s power increases, additional blades are generally required to utilize the increased power efficiently. High efficiency in modern airplane propellers comes from running the blade tip speed close to the speed of sound.
The perfect propeller design aims to convert the airplane’s engine’s energy into the thrust that propels the aircraft forward. Looking at an airplane propeller, you can see that its blade angle varies as you move from the base to the blade’s tip. This variance has to do with the fact that the blade’s speed is lower inboard and higher at the tip. The blade’s varying angle ensures that all of the thrust generated is about equal across the blade’s whole.
Stockton Propeller is a full-service governor, metal, and composite propeller overhaul and maintenance facility. We provide service to individuals, FBOs, and Air Carriers. For today’s aircraft propeller repairs, contact Stockton Propeller.