Will Da Vinci's helicopter ever fly?

An overview of Da Vinci’s helicopter concept - Aerial Screw

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Five centuries ago, Leonardo da Vinci dreamed of a helicopter-like machine. The genius of his design was that the operators would remain stationary even while the rest of the mechanism rotated.

How did Da Vinci keep the operators stationary?

If you observe the mechanism carefully, the secret becomes clear. While the spiral propeller spins, the central shaft remains stationary. Operators stay in place because da Vinci’s clever bearing placement creates a manual treadmill effect.

Da Vinci used a powerful design technique to make this heavy machine fly. While we know a simple propeller works due to the airfoil principle, da Vinci’s screw can be viewed as a collection of many individual propellers combined. To produce lift, this screw rotates counterclockwise.

Da Vinci believed that this large, screw-like surface area would generate a tremendous amount of lift. To achieve stationary control, da Vinci utilized bearings that isolated the baseplate from the top plate. He also added another set of bearings to isolate the top plate from the central shaft.

At first glance, one might assume da Vinci directly connected the spiral wing to the central shaft. Instead, da Vinci attached bearings there as well, ensuring that specific sections (highlighted in green) remain completely stationary while the rest of the assembly rotates.

The mechanism of the Aerial Screw

An external operator could easily spin the spiral screw. This spinning wheel spins the propeller since they are connected with the help of a few strings. This is not what Da Vinci wanted. If the operator were inside and attempted to rotate the spiral wing, what do you think would happen in this case? The spiral wing would definitely spin.

Da Vinci enhanced the design by adding more spokes to the wheel. When the operator walks, the wheel spins backwards. Recognizing the potential danger to the operator, he added a lever attached to the stationary shaft so operators could hold on and maintain balance. Da Vinci believed that with additional operators, the propeller would achieve high speed, the lift force would further increase, and eventually, the machine would lift off from the ground.

Da Vinci called this machine the Aerial Screw. What do you think? Would it generate enough force to overcome gravity? Let's prove it.

Aerodynamic Comparison : Aerial Screw vs Dragonfly Propeller

To answer this question, we made a lightweight version of da Vinci's helicopter. We are going to compare it with a dragonfly propeller. As expected, the dragonfly propeller flew well, but da Vinci’s aerial screw struggled to fly. If you observe carefully, it is able to balance its weight for a few seconds before coming down. The lift produced by the aerial screw is not able to overcome its weight. What are the reasons behind this?

1. Weight

Although the Aerial Screw generates significantly more total lift than the dragonfly propeller, aerial screw is really heavy. Nearly three times as much as the standard propeller.

2. Drag

The surface area of the Aerial Screw is eight times larger than that of the dragonfly propeller, which translates into eight times more drag force. This means, the initial speed you are giving to the aerial screw will quickly vanish due to this high drag. This is why the aerial screw fails to lift despite giving a good initial speed.

Even if we use modern lightweight material for the DaVinci’s aerial screw and power it with a powerful lightweight electric motor, this device will fail to lift. The drag force acting on it would be too high.

This is the drawing of Da Vinci’s Aerial screw. His complete design, along with detailed notes, appears in his famous notebook, Paris Manuscript B. Da Vinci only finished the drawing and left it as a concept. There is no evidence that Leonardo da Vinci ever built a physical model of his Aerial Screw.

The physical model of Da Vinci’s Aerial screw is available in many museums around the world. Many of these models were built in the 20th century, often by meticulously following the materials and methods Leonardo specified in his notebooks.

The modern science takes another look

Can da Vinci's Aerial Screw be modernized for modern aviation? Modern drones generate significant noise. However, a research team from Johns Hopkins University discovered that an aerial screw propeller produces substantially less noise for the exact same amount of lift generated by conventional rotors. Beyond weight and drag, a research group at Delft University of Technology identified another fundamental aerodynamic issue using CFD (Computational Fluid Dynamics) analysis: tip vortices. They found that pressure losses occurring as air flows from the high-pressure region to the low-pressure region at the blade tips were far too high in da Vinci's original geometry.

By modifying the blade geometry to mitigate tip losses, the Delft research team proved through simulations that an updated version of the Aerial Screw is capable of vertical takeoff.

We should appreciate the way the great mind of DaVinci worked to build mankind’s first flying machine. I hope this article explain why Leonardo da Vinci’s aerial screw didn’t fly? What other historical designs would you like to see analyzed with modern aerodynamics? Let us know in the comments below!