Propeller drawings might seem like any other drawing, but they aren’t. Any propeller, being a boat, helicopter or airplane is featuring complexity far more challenging than the regular profile of the vehicle itself. We’re going to talk about airplane and drone propellers in this article, but there are few differences in theory with the rest. So whatever you are about to read, goes for most of the props out there.
The propeller is challenging because its cross sections are different along its length. Its twist too. They are inter-related properties. It seem tricky at first, but let us do some explanation and all will fall into place. Any propeller has rotational speed. Around its hub, rotational speed of a airplane prop will have a certain value. That value will increase with the diameter of the propeller. Thus, any cross section of the propeller, depending on its distance from the hub will have different speed, often reaching two or three times the speed of the first third of the prop’s length. That again – goes for all propellers, but with airplane, all those factors are more pronounced.
Of course, that requires different thickness, different design and many other considerations, including supersonic speeds at the end of the propeller. Yes, you read that right. Propeller tips sometimes feature supersonic speeds. Not dwelling into the fluid dynamics it is enough to say that this creates some problems. That is why many modern helicopters have their blade tips angled. Drawing-wise, this creates even more challenges. You got to make the prop efficient and quiet. Designing its profile meaning testing various cross sections and re-draw everything up until you achieve a balance between the forces acting upon the moving part.
Back to the drawings. Now that you understand the basics, you can imagine that the twist and the cross sections of any propeller require different plans. Interestingly enough, this opens the door for alterations, nowadays especially important in drone propeller design. Once you get the separate blueprints of the prop, you can cut it in sections, thanx to the current vector drawing technology. Then, the separated elements can be divided and altered. Meaning that you can get a prop, ‘cut’ the tips /or more/ of the prop and modify it deeply.
Why drone propellers are especially important? Well, drones are relatively fresh thing on the commercial market. Many strive for speed and without serious research, design and numerous drawings, there wouldn’t be any progress. But with the help of software and sectional-drawing we can now have multiple variations of props for one an the same vehicle. They are often called speed props. Sometimes, even competition drone pilots make their own blueprints and designs. It isn’t easy, but it is doable thanx to the computers.
All this would have not been possible without first doing the 3D designs, blueprints, cross sections and various alterations. It is possible thanx to the modern software and our beloved vector drawing techniques. So next time when you see a high-speed prop plane, a helicopter or a sport drone, think about it – it all started as an idea, but then with the help of technology – came to life.