The top 5 constraints to my windmill project are as follows:

Aesthetic:

I want the windmill to have a classic look, like the ones that are commonly seen in the countryside. Ideally, it will be something that I can display in my yard that will look authentic.

Material:

The material selection is an important part of the project. For the base itself, I will need something that is solid and stable enough to resist the wind and the movement of the blades, while being durable enough to withstand the weather. For the blades, I will need something that can be designed to respond to the wind forces, while being durable and secure.

Functionality:

The blades of the windmill will need to spin and change speeds to respond to the wind. Though the blades spinning is the main function, it would be interesting to see if it could serve some kind of other purpose as well. I am still trying to think of ideas for what else it could do to keep it more in line with real windmills, which were created to mill grains.

Size:

The windmill will need to be a reasonable size, or else the material costs could be too high. I also want it to be a couple of feet tall for practical reasons, as a giant windmill would be extremely difficult to move or find a place for.

Budget:

I do not want to spend too much money on this project, so I will look to utilize found materials as much as possible. A lot of the budget will likely need to be used on the blades of the windmill, as those are the most important the functionality of the project.