Are Helicopters Gyroscopes? - Smarter Every Day 48

TL;DR

Helicopter blades operate 90 degrees out of phase due to gyroscopic precession, which causes forces to act 90 degrees later than expected.

Transcript

Hey it's me Destin. Welcome to Smarter Every Day. So you know you're in trouble when you have to break out the tinker toys to explain a concept. What are you gonna build? (son) Tinker toy ducks, scrod and rolls over your ham. [??] Good idea. What are you gonna do? (Daughter) The sunset. The sunset. OK. So we're gonna start building. Go. Alright he... Read More

Key Insights

• 🚁 Helicopter blades can change pitch through cyclic pitch.
• 🚁 Gyroscopic precession is responsible for the unexpected movements of helicopter blades.
• ❓ Gyroscopes and spinning masses have similar principles.
• ❓ Forces on spinning blades take effect 90 degrees later due to gyroscopic precession.
• 🏋️ Tilting a helicopter forward requires adding more lift on the side rather than the back.
• 🧑‍🦼 The camera experiment with bicycle wheels demonstrated gyroscopic precession.
• 🧑‍🏭 Forces applied orthogonally to the plane of rotation act 90 degrees out of phase.

Questions & Answers

Q: How do helicopter blades change pitch in the rotor disc?

Helicopter blades change pitch through cyclic pitch, which allows them to tilt up and forward or backward.

Q: Why does adding more lift on the side of the helicopter tilt it forward?

Adding more lift on the side of the helicopter causes gyroscopic precession, resulting in the helicopter tilting forward instead of backward.

Q: How does gyroscopic precession affect helicopter blades?

Gyroscopic precession causes forces applied to spinning helicopter blades to take effect 90 degrees later, resulting in unexpected movements and changes in pitch.

Q: How did the experiment with bicycle wheels demonstrate gyroscopic precession?

The experiment showed that forces applied orthogonally to the plane of rotation, such as adding force straight up, cause the blades to rotate 90 degrees from where the force is applied.

Summary & Key Takeaways

• Helicopters can change pitch in the rotor disc, which is called cyclic pitch.

• To tilt a helicopter forward, more lift is provided on the side of the helicopter rather than on the back.

• Gyroscopic precession causes forces on spinning helicopter blades to take effect 90 degrees later, resulting in the helicopter rolling sideways instead of forward.