Rebecca's Group's Turbine

Table

Questions:

1) Our rotors made out of playing cards worked better than our ones made out of feathers. The reason for this is because the cards were sturdier and so held wind/air pressure better to cause it to turn without bending or letting air pass through. Therefore, our playing card rotors produced more power than the feathers.

2) Max output difference (spreadsheet) between ours and top

3) Our card model had some limitations. First limitation was that it was short so it couldn't reach out far and capture more wind or pressure to allow it to move better and faster with more strength. Another problem was that we couldn't curve the rotors to allow them to cup the wind better.

4) How do an airplane and windmill use pressure to fly and rotate?An airplane uses pressure to fly. To do this, it gathers a lot of speed using Bernoulli's principle of an increase in speed of a fluid decreases pressure. In saying this, the faster a plane goes the less pressure there is keeping it down allowing it to rise up with little resistance. The windmill uses pressure to rotate by having it press against its rotors not just to glance off but to force movement and create a rotation.

5) The rotors had to be tilted in order to catch the wind. If the rotors were to remain straightir pressure and force of wind would just slide right over and off. Because of the tilt, part of the pressure was captured and able to turn the blades.

6) The rotors of a windmill and sails of a sailboat are similar in using the same principal as they both use wind and air pressure to move and operate. Wind is captured on rotors to create a thrust to move the rotors in a circular motion to create energy. Sails take the wind and use it to thrust up against it allowing the force to move the object forward. So, they both use pressure to move. 

Windmill Questions

1)Which rotor had the most power and why?
The rotor that worked the best was the one that was made out if milk jug, we got it to work then it didn't work at all when we added weights, so we tried bending the wings all in the same directions a it worked great!
2)What was different about the design with the most out put?



3)What are the limitations of the model?
The limitations are that the milk jug was flimsy and kinda moved, also it didn't catch a ton of wind it caught enough

Windmill Results

Mass    Height   Energy   Power   Time
7.83g   .7874m  60.54j     1.06w    20s
14.7g   .884m    128.85j   7.336w  20s

• Which rotor has the most power? Why? The second one because it was wasn't too light and wasn't too heavy.
• What was the different  from the design with the most output? It had longer wings.
• What are the limitations to the model? We could've made it bigger and maybe try to get more weights to be lifted.
• How do airplanes and windmills compare? They use their wings to move.
• Why did we twist the rotor blades at an angel to grab the wind? So that it would spin easier and faster.
• Explain how windmills and sailboats use the sane principles. When the wind hits from a distance it seems to move faster, you don't want to be right up close to the windmills and sailboats because it will slow it down or won't even move at all.

rotor

Results:

Mass	Height	Time	Power
8.6 g	92 cm	15 sec.	5.2 watts
27.34 g	92 cm	36.84 sec.	6.70468 watts
30.66 g	92 cm	27.6 sec.	10.33 watts

1.) Which rotor had a better design? why?
Our second rotor had the best design, it was lightweight but long and it produced a decent amount of energy
2.) what is different about the design with the MOST output from yours?


3.) What were the limitations of your model?
Our model was limited to a mediocre amount of weight because it had a rough design and was pretty heavy.

Time Mass Height Energy Power
76 seconds 8.84g .13m 11.285144 .15 Watts

Our Turbine that had the most power was our small one made out of cut up pop cans with a small dowel. It had the most power by default. The other didn't work. Ours was short and thin, looked like it could have been a scale model. The limitations of our model were that it wasn't heavy enough to support itself, and slid around. The other just wasn't glued well and had a smaller blade than the others. Airplanes and Windmills work by a change in air pressure. Airplanes also have small blades that come off of the end that catch the wind at a proper angle to cause lift. That same property can be applied to windmills. It has a slant on one side of the blade, which allows it to catch wind and not lose a lot of air. That is why it is necessary to have the rotor blades at an angle. The sail on a sailboat is long and thin, just like a successful rotor. It also has a slight angle, and catches the wind. On the correct angle, it is caught by the wind and moves, just as a windmill catches the wind and spins.

Windmill Results

Windmill Type	Length of String	Mass	Time	Power	Energy
Pop can	85 cm	8.8 grams	12 seconds	73.45 joules	6.121 watts
Paper	85 cm	8.8 grams	10 seconds	73.45 joules	7.345 watts
Paper (test 2)	85 cm	13.77 grams	12 seconds	114.94 joules	9.578 watts

1.) Our paper rotor had the most output because the rotor was more reliable when it was spinning. It didn't stop and start as much as the other one so it gained more momentum.

2.) The paper rotor had more surface area and a greater angle on the blades.

3.) Some limitations to our rotor are that the blades are not very long so they won't be able to use as much air to spin.

4.) When the wind hits the edge of the blade, it splits the wind in two. One way goes above and has no effect. The other goes down and gets pushed down by the angle of the wing. The wind then pushes the plane up. The same basic effect goes for the windmills.

5.) It is necessary to twist the rotor blades in order for it to be able to catch and redirect the airflow to one side in order for it to spin.

6.) The rotors of a windmill and the sail on a sail boat both catch the air in order to move. The rotor moves the air to one side to spin and the sail catches the wind and holds it to move straight forward.

Wind Energy

Wind Energy

Wind Energy	Mass in grams	Height in cm	Time in seconds	Energy in jewels	Power in watts
Playing Cards 1	8.83	76	104	65.90	0.63
Playing Cards 2	34.54	76	77	257.78	3.35
Feathers 1	7.06	76	49	52.69	1.08

1. The one of our windmills that worked the best was the playing card version (as opposed to the turkey feather version). Both of the turbines were built with a base of foam and had three blades in the foam at an angle. However, the playing card blades caught the wind better than the feather blades did. This was because the cards were uniform,rigid, and held their shape while the feathers varied in size, were easily broken, and were more flimsy. The design worked both times, but the cards were a lightweight and sturdy material, proving more efficient than the feathers.

2. The one of our classes that worked the best was the one that Miranda and Kelsey made(16.69 w). However, they did not have a picture, so I'm not sure why it worked better. The second best was made by Nate, Mike, and Evan, (10.03 w) but they also didn't have a picture. The third best was made by Jacob and Tyler(9.85w) who also didn't have a picture. (I'm sensing a pattern here.) The fourth best was made by Sofia, Jessica, and Samantha (6.5 w). Luckily, they did have a picture. Their design included slightly cupped blades that were taped to the dowel using masking tape. The blades were about six inches long and three or four inches tall. I think that the reason theirs worked better than ours was because their blades, made of cardboard, were sturdier and heavier than ours. They were all of a uniform size, kept their shape, and caught the wind easily. They were attached to the dowel in a sturdy way and were able to turn and lift weight.
3. Some limitations on our model were the size, design, and materials. Since we used playing cards and feathers for our blades, they weren't able to lift much due to their light weight. Our blades were also rather short; longer blades output more energy. The feathers especially were somewhat flimsy. Due to the work we did with them, they began to tear and not catch the wind as well. We used foam to hold the blades in place, which was not the firmest. The blades were also not all at the exact same angle of tilt, making them less efficient. The playing cards did not have any curve in them, and were only tilted, making them less aerodynamic and less functional. Since the blades were not all uniform (mainly the feathers) the wind did not catch them all the same. It would have worked better to have slightly stronger and better attached blades that were all uniform, longer, and more curved.

4. Both airplanes and windmills are affected by Bernoulli's Principle: as velocity of a fluid increases, pressure decreases. Airplanes use this change in pressure to fly; as they go faster, there is less pressure above the plane and more beneath it, creating lift so they can stay in the air. As a windmill begins to turn faster, there is less pressure beneath the blades and more above them, causing it to continue the turning motion. Much of this is due to curvature and tilting of the blades/wings, since the wind moves faster over a curved surface.

5. It is necessary to twist the rotor blades at an angle so they can catch the wind. If you have flat blades, wind blown on them will just be stopped. If the blades are at an angle, they have the opportunity to catch the wind and turn, giving off energy. Rounded or cupped blades also don't work, since the wind will fill up the blade and not move anything; tilted blades catch and spin.

6. Rotors on a windmill and the sail of a sailboat are both designed to catch the wind and move forward. A sail is tilted so when the wind catches it, the boat is moved in that direction. The blades of a windmill are tilted to catch the wind and turn in that direction. The tilt and turning factors show how windmills and sailboats operate on the same principle.