We are at Round #99 of the LMAC contest!! Very exciting as we head toward the 100th edition of this collage challenge, coming up in just a few days. What fun I had in designing this week's picture.
It all started with @shaka's magical template photo:
I knew I was going to put @quantumg's gnome (borrowed from the #LIL Gallery) in the collage.
The story in my collage evolved from that. I will explain more about the evolution later. Right now, I want to talk about helicopters.
How many times have we seen helicopters flying around? A lot. And yet, do we, do I, understand how they stay up there? I do now, sort of.
Here's a brief explanation:
They are held up by air. Really. Just air, but air that is directed so that helicopters, and airplanes, benefit from 'lift'. The airplane generates lift through movement and the design of the craft. Air moves over the top of the plane faster than it moves under the plane. The faster air moves, the less pressure it exerts on a surface. Therefore, the slow moving air under the plane exerts more pressure than the fast moving air over the plane. It is this pressure from slow moving air that keeps the plane aloft.
Lift is based on something called Bernoulli's Principle. While Bernoulli worked with liquids, the same principle applies to air because air 'flows'.
Illustration of Bernoulli's Principle
Image credit: L3 PAE. Used under CC 3.0 License. Note the paper rises as air is blown rapidly over the top.
In the case of a helicopter, lift is created by the rotation of the helicopter blades. If the blades stop rotating, the helicopter falls out of the sky. And, if a plane stops moving, it falls out of the sky. In both cases, the craft cannot stay aloft without lift.
Bernoulli's Principle is also at work when the roof blows off a building during a hurricane. Rapidly moving air across the top of the roof allows the pressure under the roof--in the house--to build and blow the roof off. A gust of wind sometimes adds a little push.
Roofs Blown Off Buildings in Pensacola Florida During Hurricane Ivan
Image credit: U.S. Navy photo by Harry White. Public domain
Planes and helicopters change direction by altering the direction of airflow. Here is a GIF that illustrates how a plane changes direction, merely by alternating airflow over the wings. The little apparatus that is moving up and down in the GIF is called an aileron.
Aileron Roll
Image credit: Nancy Hall from NASA's Glenn Research Center. Public domain.
Changing the direction of a helicopter takes skill. The pilot has to adjust the blades on the tail, and/or individually adjust the main rotor blades (overhead).
Performing Repairs on a Helicopter's Main Rotor Blades
Image credit: Tequask. Public domain
First I isolated the part of the house I wanted to work with.
Then I decorated the house with flowers I had drawn in past years, for a book I had written.
I knew I wanted the house to be on clouds so I borrowed @louis88's clouds from the #LIL Gallery.
I wanted a gnome on the roof so I borrowed a ladder from the #LIL Gallery. This is a ladder I had contributed a few weeks ago.
Finally, I wanted a helicopter. Thank you, @amilcar14 for the helicopter.
Now it was simply a matter of placing a gnome on the helicopter and timing the movements of the different elements. It worked out pretty much the way I planned it, which is unusual.
I don't compete in the contest. I love the contest. As the 100th birthday approaches, I look back and think of what I didn't know when I made my first collage. I think of all the the people I didn't know, and have met since then. LMAC is a gift to me and to many others. Now we have a library that will benefit our community and all of Hive.
Please contribute to LIL, and help this vibrant part of Hive to grow. Rules and procedures are explained in this blog by @shaka. The rules for the collage contest are explained in this blog, by @shaka. If you have any questions, or you just want to say, "Hello", you can find us at our Discord channel.
Finally, keep an eye open for next week's collage contest. We have a special edition planned. Coming soon in your LMAC community.
