Aerodynamics of a helicopter blade

[mathisrad]

TL;DR Summary: Making a model helicopter for SCIOLY

I have a national tournament for Science Olympiad, and for one of my events (topics), my partner and I are essentially starting over. The event name is Helicopter, and requires students to make a model "Helicopter," although it doesn't look like any helicopter I've seen, ha ha, that flies in the air using the torque from a wound-up rubber band. Most teams currently use a kit, or predesigned model, but we've noticed many flaws with it, and hope to modify it. Neither my partner nor I are familiar with aerodynamics, however, and only know the basic parts of a rotor blade (pitch angle, angle of attack etc) We don't know any formulas that relate these variables. Here's a demonstration of one of the better kits this year (and we're using as a base) https://www.youtube.com/watch?v=-oYW4sI0hSM More info on helicopter is found on his channel. While redesigning the helicopter, we will keep the fuselage the same, but replace the top rotor with a freedom flight top rotor: So to make a long story short, I would appreciate any information on aerodynamics (stuff that is hard to find, but important to know) resources, or just a general number I should keep in mind while designing the helicopter. Also wondering what would be the pitch angle that would provide the most optimal Lift (I understand I haven't provided enough info, just a formula would suffice) I am familiar in basic vector principles, and Calculus.

 

[jbriggs444]

TL;DR Summary: Making a model helicopter for SCIOLY

In this forum, students are expected to show their work before help can be offered. You say that you know about pitch, angle of attack and some other unspecified stuff. But you explicitly deny having seen any formulas.

Let me give you this much...

What is aerodynamic lift? What is induced drag? Are there any formulas that relate them?

 

[berkeman]

Neither my partner nor I are familiar with aerodynamics, however, and only know the basic parts of a rotor blade (pitch angle, angle of attack etc) We don't know any formulas that relate these variables.

Here is a good PF Insights article that will give you the basics of airfoil dynamics (lift and drag):

https://www.physicsforums.com/insights/airplane-wing-work-primer-lift/

And there are some things that you need to think about that are specific to helicopters, like stabilization of yaw:

https://en.wikipedia.org/wiki/Helicopter

 

[Lnewqban]

Neither my partner nor I are familiar with aerodynamics, however, and only know the basic parts of a rotor blade (pitch angle, angle of attack etc) We don't know any formulas that relate these variables.

Please, see this excellent reference that may help you and your partner:
https://www.av8n.com/how/#contents

 

[berkeman]

Please, see this excellent reference that may help you and your partner:
https://www.av8n.com/how/#contents

Wow, nice reference! And Professor Denker is quite accomplished -- I especially like the part where some of his pranks at CalTech were used in the movie "Real Genius".

About the Author

John Denker was an undergrad at Caltech. During his junior year, he founded a successful small software and electronics company which did pioneering work in many fields including security systems, Hollywood special effects, hand-held electronic games, and video games. Also while still an undergrad, he created and taught a course at Caltech: “Designing with Microprocessors”.

His doctoral research at Cornell examined the properties of a gas of hydrogen atoms at temperatures only a few thousandths of a degree above absolute zero, and showed that quantum spin transport and long-lived “spin wave” resonances occur in this dilute Bose gas. Other research concerned the design of ultra-low-noise measuring devices, in which the fundamental quantum-mechanical limitations play an important role.

Dr. Denker joined AT&T Bell Laboratories and worked there for many years, serving in roles including Distinguished Member of Technical Staff, Department Head, and Division Manager. His research interests include computer security, election security, internet telephony, and “neural networks” – combining ideas from biology, physics, computer science, and statistics in order to devise new types of information processing systems. He has also invented novel low-energy “adiabatic” computing systems.

In 1986-87 he was Visiting Professor at the Institute for Theoretical Physics (University of California, Santa Barbara). He has served on the organizing committee of several major scientific conferences.

He holds numerous patents and has written over 50 research papers and one book chapter, and edited the book Neural Networks for Computing. He has lectured widely.

He is well known as a prankster and prototypical mad scientist. Some of his exploits were featured in the films “Real Genius” and “The Age Seeking for Genius”, as well as in publications such as “Time” and “IEEE Spectrum”.

John Denker is certified as a Commercial Pilot, Flight Instructor, and Ground Instructor. He is an FAA Aviation Safety Counselor. He is a past member of the board of trustees of the Monmouth Area Flying Club, and a past member of the National Research Council Committee on Commercial Aviation Security.