The propeller can quite literally take the plane to the next level. In order to work quantitatively the students need to take two things into consideration. How much thrust is being produced and how much energy is needed to produce said thrust. There are many different way that we can effect these two variables but I'm going to leave that up to the designers (students). They can go online and find and immense amount of information to design a propeller. What they cannot find online is this specific thrust and efficiency of their propeller. So how do you test these two? Let's take a look at the development of my tester from simple to severe.
*Note: If you just want to see the final version that I'm using, scroll to the bottom. But, by looking at what I did you might be able to make a lower cost or better one.*
Version 1: Getting it done
Here's what it looks like in action. The power supply has both voltage and amperage.
- Make a better mount for the motor
- Make a better scale
- Have a way to adjust the rubber band to account for wear and tear
- Make it look better
Version 1.2: A Nip and tuck
The fins had 3 simple features. First, they snapped into the basket to keep square. Second, they had integrated hook for the rubber bands. Third, they had a laser rule engraved on them.
I reused the same chassis putting several holes to adjust the tension of the rubber bands. This would help be zero out the weight of the basket, motor, and propeller.
With the improvements, the device looked good. However, the function was the same. It just allowed for a great visual. I knew that if i was going to get accurate readings i was going to have to incorporate the spring scale.
Things to work on:
- Integrate spring scale
- Allow to stand alone (Sturdy)
- Visual apperence
Version 2 here I come!
Version 2: The full redesign
Version 2.2: small but mighty changes
- The rods keep everything alined
- A drop of oil keeps it moving smoothly
- The basket holds the motor tightly
- Spacer at the top are used zero out the spring scale
- Spaces allow of air to flow freely
- The fit of the finger joints was fixed and didn't need any glue