The Effect of Fuselage Nose and Tail Shape on Aerodynamic Drag

Researched by Andrew W.
2003-04
PURPOSE

The purpose of this experiment was to determine the effect of different shaped fuselages on the amount of drag.

I became interested in this idea when I flew in an airplane and I kept wondering how it flew, being that heavy.

The information gained from this experiment might be used when designing a new airplane. Also engineers need to know what shape is the most aerodynamic so it will get to where it is going faster.

HYPOTHESIS

My first hypothesis was that the conical tail would create the least amount of drag.

My second hypothesis was that the hemispherical nose would create the least amount of drag.

I based my hypothesis on Microsoft Encarta, which stated, “An airfoil minimally disturbs the air as it travels, so the airfoil experiences little drag. ” An airfoil has a semi-circular leading edge and a wedge shaped trailing edge. This is much the same as a hemispherical nose and a conical tail.

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EXPERIMENT DESIGN
 

  • The constants in this study were:
  • The wind tunnel I used
  • The fan in the wind tunnel
  • Speed of the wind
  • Spring scale used to measure the drag
  • Weight of fuselage 
  • Material of fuselage
  • Time that the fuselage is left in the wind tunnel
  • Testing procedures


The first manipulated variable was the shape of the nose section of a fuselage.

The second manipulated variable was the shape of the tail section of a fuselage.

The responding variable was the amount of drag the different shaped fuselages created.

To measure the responding variable I determined the amount of force the object pulled on the spring scale.  

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MATERIALS


QUANTITY		  ITEM DESCRIPTION
1  20” x20” board
2  right triangles from a 2’x2’ square, cut from. 75” plywood 
16  6x1. 5 screws
28  6x. 75 screws
14  angle brackets
1 Roll of clear packing tape
1 Roll of electrical tape
1 Roll of duct tape
1  20” box fan
2  leaf blowers
1  metal pipe 12” diameter
2 pieces of plastic
2 PVC pipe 5” long, 2” in diameter
2 Styrofoam oval shapes
2 Styrofoam sphere shapes
2 Styrofoam cone shape
2  Styrofoam bell shape
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PROCEDURES

  Building a Wind Tunnel

  • Align metal pipe to center of 58cm x58cm plywood
  • Screw the metal pipe in to the wood
  • Screw the wooden angles to the side for support
  • Make hole in metal pipe for test section window
  • Put in window for test section
  • Cut hole for leaf blower
  • Steady one leaf blower in the hole


  Building fuselage shape
a. Nose shapes

  • Buy 4 styrofoam shapes cone, sphere, bell, and an egg
  • Carve them so they fit in the PVC pipe 
b. Tail shapes
  • Buy 4 of the same styrofoam shapes as for the nose shapes
  • Carve them so they fit in the PVC pipe 


Experiment
1. Hang piece of PVC pipe in test section of wind tunnel
2. Put first tail shape on back of PVC pipe
3. Put first nose shape on front of PVC pipe
4. Test for sixty seconds in wind tunnel
5. Record force from spring scale
6. Repeat steps 3-5 four times for all four nose shapes without changing tail shapes
7. Take first tail shape off
8. Put second tail shape on back of PVC pipe
9. Repeat steps 3-6 
10. Take off second tail shape 
11. Put on third tail shape
12. Repeat steps 3-6
13. Take off third tail shape
14. Put on fourth tail shape
15. Repeat steps 3-6
16. Average the amount the fuselage drag force is created on the scale for each tail shape
17. Average the amount the fuselage drag force is created on the scale for each nose shape

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RESULTS

The original purpose of this experiment was to determine the effect of different shaped fuselages on the amount of drag.

The results of the experiment were that the bell shaped nose created the least amount of drag out of the nose shapes and the conical tail created the least amount of drag out of the tail shapes.

See my data table and graphs

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CONCLUSION

My first hypothesis was that the conical tail would create the least amount of drag.

The results indicate that my first hypothesis should be accepted because the conical tail did create the least amount of drag of the tail shapes.

My second hypothesis was that the hemispherical nose would create the least amount of drag.

My second hypothesis should be rejected because the bell shaped nose created the least amount of drag of the nose shapes.

Because of the results of this experiment, I wonder if I used a bigger selection of shapes, (mimicking actual plane nose and tail sections) if that would make a difference. I also wonder if the smoothness of the surfaces of the fuselages would matter. Finally, I wonder if the length of the fuselage would make a difference in drag.

If I were to conduct this project again I would be more precise on my carving the styrofoam shapes and do more trials for each nose and tail shapes. I would also test each shape for a longer time to get better results. I would also generate more wind in the wind tunnel. Finally I would find a more accurate way to measure force.

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RESEARCH REPORT

Introduction
Humans need transportation in their daily lives. Today air travel is the most efficient way to get from place to place. It also needs to be affordable. To make that possible engineers have to make planes aerodynamic so they can move through the air without disturbance and creating little friction. If we do that it will enable the plane to go the farthest distance the fastest.  

The 4 Forces
The four forces of flight consist of thrust, drag, lift, and gravity.   Balancing the four forces is the challenge of flight. When thrust is greater than drag the plane will accelerate. If lift is greater than gravity it will climb. Aerodynamics is the scientific study of those four forces.

Thrust
Thrust is the force that causes the forward motion of a plane.   The plane is either pulled by propellers or pushed by jet engines.   When the airplane speeds up on a runway, the thrust is getting greater until the plane takes off. Helicopters also use thrust, their blades on top are used just like that of on a plane. They tilt forward and push the air back, which makes the helicopter move forward. As a jet engine burns fuel, hot exhaust gases are forced backwards at high speeds and that make the plane move quickly through the air.

Drag
Drag is the force that pulls back on the plane and makes it hard for aircraft to move really quickly. Another name for drag is air resistance.   Drag is caused by friction with the air. The shape of the object affects how much drag is created. In some cases drag is good like on a parachute, which slows you down so you don’t hurt yourself landing.   Streamlined shapes are the best at minimizing drag. A wind tunnel can show how the air moves over an aircraft or object so you can tell if it is aerodynamic or not. You don’t notice drag when you are walking, but when you are swimming you can feel it. That is why you can’t swim as fast as a fish. Fish and dolphins are streamlined so they can move through the water quickly. There is more drag created when you move in water than in air because it is denser or thicker.  

A wing with high lift is probably also the one with the most amount of drag because it is so big therefore it is not necessarily the best wing for an aircraft to have. Sleek aerodynamic shapes minimize drag, and a flat object such as a cube creates a lot of drag. If the air does not move smoothly over the aircraft, more drag is created so engineers have to make aircraft rounded and smooth so they don’t disturb the air as it passes through.

Lift
Lift is the force that keeps the airplane flying in the air and not falling back to Earth. Aircraft fly by pushing air down and air pressure pushing the wing up and creating lift. Lift occurs when airflows along the top and bottom are unsymmetrical. Lift is created when the angle of attack of each wing makes contact with the airflow.   Lift is a result of change in air pressure around the surrounding wing.   Lift on a wing depends on three things: the shape of it’s cross section, velocity/airspeed, and the angle relative to other parts of aircraft.   Lift and gravity are opposite forces, lift makes an aircraft move up and gravity makes an aircraft move down. A wing is specially tilted so it will deflect air to give lift. With specially shaped wings you can create more lift.  

Gravity
Gravity is the force that offsets lift and pulls the airplane towards the ground. Gravity must be less than the lift for the plane to be able to fly. Designing a wing that is powerful enough to lift an airplane and efficient enough to fly at high speeds over long distances but is light weight so gravity doesn’t pull the plane down is a huge challenge.   When you jump up in the air, gravity is what brings you back down to the earth. If we didn’t have gravity we would just be floating like we were in space. Gravity must be over come by lift. When you can’t get enough lift on an airplane it will stay on the ground.  

Friction 
Friction is when two surfaces brush past each other creating heat and slowing the objects down. Friction wears on objects and materials making it more difficult to move fast through the air. Friction lets us move, it enable us to walk, run, or drive but at the same time it slows us down.  

There are three types of friction: air friction, sliding friction, and rolling friction. Air friction is when the object is slowed by air hitting the outer layer of an object. For instance, on an airplane air friction is what slows it down. The next one is sliding friction.   It is when two objects slide across each other. It can make the object hot. The last type is rolling friction. It is when a rolling object goes over another object and the friction slows it down. A bike tire rolls over the road and creates friction, making the bike slow down on the road.

Conclusion 
Planes today are much more advanced than the Wright brother’s plane.   Planes now mostly have jet engines. They are much faster than propeller planes. The jet engine planes can fly at supersonic speeds, and can even break the sound barrier. Planes now are mostly used for transportation and can hold hundreds of people at a time. Planes are very safe for transportation and are very effective when they are used. Today airplane travel is the fastest and most efficient way we know.  
 
BIBLIOGRAPHY

“Aerodynamics” Airplanes
  http://www. grc. nasa. gov/WWW/k-12/airplane/fuselage.html

“Aerodynamics” ENCARTA Encyclopedia Deluxe, 2001.

“Aerodynamics” Forces of Flight
  http://www. gomilpitas. com/homeschooling/explore/flight.htm

“Airplane”  Beginners Guide to Aerodynamics
  http://lerc. nasa. gov/WWW/k-12/airplane/bgp.html

“Airplanes” ENCARTA Encyclopedia Deluxe, 2001.

Dine, Michael. “Force” World Book Encyclopedia, 2002

“Forces of Flight” 
  http://www. fi. edu/fellows2/oct98/forcedef.html 

Plotkin, Allen. “Aerodynamics” World Book Encyclopedia,  1999

“Wind Tunnels” ENCARTA Encyclopedia Deluxe, 2001

“Wind Tunnels” Beginners Guide to Wind Tunnels
  http://www. geversaircraft. com/wt/wtsmall.htm 

“Wind Tunnels” How To Build a Wind Tunnel
  http://ldaps. arc. nasa. gov/Curriculum/cheap_tunnel/windpart.html
 

ACKNOWLEDGEMENTS
I would like to thank the following people for helping make my project possible:

  •  My parents for driving me to the after school work days and to school.
  •  Mr. Newkirk for correcting my report and letting me stay after school to work on my project.
  •  Mrs. Helms for helping me with my project and leading me in the right direction, also for being at the afternoon classes.
  •  Mr. Smith for helping us build the wind tunnel.

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