Optimal Blade Design and Reduction System To Lift 5lbs

In summary, the conversation was about building a windmill for a college project. The goal is to lift a 5lb mass 3ft using the energy of two 20 inch box fans. The materials allowed are pine wood, ice cream pails, floss, nuts, bolts, washers, screws, plywood, and needles. The base is modeled in CAD and there are questions about blade design and the reduction system. The person providing the summary recommends experimenting with different blade configurations and looking at established windmill designs for reference. They also suggest considering simple machines such as inclined planes, pulleys, and levers for lifting the load. The conversation ends with the person thanking the other for their advice and wishing them luck with the project
  • #1
Mastermime
3
0
Hello, I'm working on a project for my college class where we need to build a windmill that will be able to lift a 5lb mass 3ft above the ground. The energy of the wind is produced by two 20 inch box fans. We are allowed to use several materials- pine wood, ice cream pails, floss, nuts, bolts, washers, screws, plywood, needles (not sure what these would be used for). The goal is to lift the 5 lbs the fastest 3 ft above the ground.

So I have the base modeled in CAD, which you can see below. My first question is about blade design? The blades will bolted to the circular hub in the image. Based on a bit of research, I figured I would use three. Is this a wise choice?
What shape would you recommend for the blade? Once again, I modeled a blade based on my findings, which you can see below. I'm a bit skeptical about this because I feel this type of blade is too skinny for the blades to 'catch' the wind' and produce rotational motion. Perhaps I could utilize the ice cream pails for this? I just need a bit of advice for this part as we haven't learned about areodynamics up to this point.

For the reduction system, I figured I'd use a system of single movable pulleys. Does this sound like a practical approach?

Thanks

John
 

Attachments

  • pine wood.PNG
    pine wood.PNG
    12.6 KB · Views: 390
  • windmill base.PNG
    windmill base.PNG
    24.8 KB · Views: 386
Physics news on Phys.org
  • #2
You have some good questions ... but this is a project for your class. Part of the scientific process, that the project is supposed to be teaching you, is investigating the design decisions. This is the important part of the lesson. You should discover the relations yourself the best you can.

Perhaps you can model different blade designs in miniature to see what, if any, effect the different possibilities have?

You can also look at established windmill designs that are similar to the ideas you come up with and see how they are used in real life. i.e. power windmills tend to have three blades but may have two. Aircraft tend to have two blades, but may have more. Desk fans have lots of wide blades. A kids carnival windmill has 4 or 6. Farm windmills designed to pump water have a score of blades.

The scale of your design will affect the design too - the exact shape of the blades, for eg, may not be so important for small scale, low speed, windmills.

I suspect that the blade number and shape is not going to impact as much as you think - if you start with how the lifting is going to be done: do you have a choice in that? Can you use pulleys and levers? Counterweights even? If so, then quite a weak windmill can still fit the bill.
 
  • #3
Simon Bridge said:
You have some good questions ... but this is a project for your class. Part of the scientific process, that the project is supposed to be teaching you, is investigating the design decisions. This is the important part of the lesson. You should discover the relations yourself the best you can.

Perhaps you can model different blade designs in miniature to see what, if any, effect the different possibilities have?

You can also look at established windmill designs that are similar to the ideas you come up with and see how they are used in real life. i.e. power windmills tend to have three blades but may have two. Aircraft tend to have two blades, but may have more. Desk fans have lots of wide blades. A kids carnival windmill has 4 or 6. Farm windmills designed to pump water have a score of blades.

The scale of your design will affect the design too - the exact shape of the blades, for eg, may not be so important for small scale, low speed, windmills.

I suspect that the blade number and shape is not going to impact as much as you think - if you start with how the lifting is going to be done: do you have a choice in that? Can you use pulleys and levers? Counterweights even? If so, then quite a weak windmill can still fit the bill.

Thanks for the response. You made a lot of great points. I will experiment with a few different configurations to see which one yields the best results.

In regards to lifting, we recently studied simple machines so I think that is the main focus of the project. The instructions are to build a windmill that can lift 5lb 3 ft in the shortest time possible using only the energy of wind produced by the fans which are six feet away.

Correct if I'm wrong, but, based on those instructions, I would not be able to use a counterweight because that would be utilizing gravitational potential energy and I am only allowed to use the energy of the wind produced by the fans.
 
  • #4
This would be the likely objection - yes.
Inclined planes and pulleys and levers could be investigated - anything that offers a mechanical advantage would slow things down though and you need fastest time.

This is also a fairly common project - so googling for "20 inch box fan windmill lift load" should help :)
You won't get actual instructions, well you might, but you will get useful resources.

And then there's the "related discussions" section below.
Have fun.
 
  • #5
Ok thank you for your advice Mr Bridge.
 
  • #6
No worries ... and have fun with it ;)
 

1. What is the purpose of an optimal blade design and reduction system for lifting 5lbs?

The purpose of an optimal blade design and reduction system is to efficiently convert mechanical energy into lifting force to minimize the amount of energy required to lift a 5lbs object. This results in a more efficient and effective lifting process.

2. How does an optimal blade design contribute to lifting 5lbs?

An optimal blade design is specifically engineered to create maximum lift with minimum drag. This is achieved through careful consideration of factors such as shape, angle of attack, and surface roughness. By reducing drag, the blade can generate more lift, making it easier to lift a 5lbs object.

3. What role does the reduction system play in lifting 5lbs?

The reduction system works in conjunction with the blade design to increase the efficiency of the lifting process. It reduces the amount of power needed to operate the lifting mechanism, making it easier to lift 5lbs with less effort.

4. What are the key factors to consider when designing an optimal blade for lifting 5lbs?

The key factors to consider when designing an optimal blade for lifting 5lbs include the shape and size of the blade, the angle of attack, the material used, and the surface roughness. These factors all affect the lift and drag forces acting on the blade, and must be carefully optimized for maximum lift efficiency.

5. How can the optimal blade design and reduction system be improved for lifting 5lbs?

The optimal blade design and reduction system can be improved through ongoing research and development. This could involve testing different blade shapes and materials, as well as implementing new technologies for the reduction system. Continuous improvement is key to achieving the most efficient and effective lifting of 5lbs.

Similar threads

  • Mechanical Engineering
Replies
17
Views
2K
  • Mechanical Engineering
Replies
7
Views
1K
  • Mechanical Engineering
Replies
1
Views
3K
Replies
14
Views
2K
Replies
8
Views
911
Replies
4
Views
1K
  • Sci-Fi Writing and World Building
Replies
21
Views
805
  • Mechanical Engineering
Replies
13
Views
2K
Replies
2
Views
1K
Replies
12
Views
5K
Back
Top