Modeling a Foam Plane

A step-by-step tutorial on using Solidworks to model an airplane

Background

This tutorial is going to go over creating a foam plane assembly out of individual parts. The model will be a bit over 3-feet long with a 5-foot wingspan

Foamyrender

This tutorial is intended to be a crash course that give users a glimpse of intermediate Solidworks functions and to produce a plane that could be manufactured with little (some) difficulty in real life.

Preresquisites

This tutorial assumes that you have installed Solidworks and have completed the introductory tutorials such as placeholder

Tutorial

Helpful Tips:

  • Click "Ctrl + 7" (Orthographic View) or "Ctrl + 8" (Normal View) if you are having difficulty moving around your model
  • The origin is your friend, it's a good habit to not ignore it
  • If you have multiple Solidworks windows (i.e. parts, assemblies, etc.) use "Ctrl + Tab" to navigate between them
  • On the bottom of the page, there is a video showing the entire process

Fuselage

  • Begin by creating a New Part in Solidworks
  • Make a sketch on the top plane and place a center rectangle on the origin
  • Dimension the rectangle to be .75 meters long and .10 meters wide
  • Extrude the rectangle to .10 meters tall
  • Set the material to be Polyurethane Foam Rigid
  • Create a sketch on the side (parallel to front plane) of the rectangular prism
  • Add a vertical centerline and make it .25 meters away from the "front" edge
  • Connect a line from the bottom of the center line to the top of the opposite (far) corner
  • Delete the coincident relationship
    • The coincident relationship makes points touch each other
  • Use the smart dimension tool to make the angle between the newly formed line and the bottom 8.5°

Foamplanescreencap 1

  • Find Extend Entities and extend the slanted line until it reaches the top
    • The tool is under "Trim Entities"
    • To use this tool, drag from one line to another (not click)
  • Use the line tool to complete the triangle
  • Extrude that small triangle
    • Find Extrude Boss/Base and selct the triangle
    • Under the "Direction 1" dropdown menu, select "Up To Surface" and select the surface you want to extrude to
  • Create a new sketch on the same surface
  • Click the old sketch and convert entities
    • This will allow you to use a previous sketch in another feature
  • Create a cut extrude with the larger triangle, similar to the smaller one.

Foamplanescreencap 2

  • Make a new sketch on the same side of the fuselage
  • Create a centerline connecting the center of the short end of the retangle to its top
    • Centerlines are construction lines by default, making it useful to make reference lines

Foamplanescreencap 3

  • From the center of the center line, draw a corner rectangle that is .1 meter long and connects to the top
  • Cut extrude the entire rectangle
  • Create a face fillet from the recently extruded rectangle
    • Fillets help smooth out parts, and we be especially useful in 3D printing
    • After selecting Fillet, under Fillet Types, choose Face Fillet (it might be helpful to turn on "full preview")
      • Then select the vertical face for the first face selection (blue) and the horizontal face for the second face selection (pink)
      • Under fillet parameters, select "hold line" and select the topmost edge
  • Please save your part

Wing

  • Make a new part
  • Make a sketch on the top plane and place a center rectangle on the origin
  • Smart dimension the rectangle to be .3 meters long and .07 meters wide
  • Extrude it to be .007 meters tall
  • Download this file: Airfoil
  • Insert it into Solidworks
    • Create a sketch on the .007 meters tall and .07 meters long side
    • Go to the "Tools" Dropdown menu
      • Go under Sketch Tools and select "Open Sketch Image"
    • Disable lock aspect ratio and fill the side of the wing with the image
    • Make the black transparent by selecting "User Defined" under transparency, selecting black with the eyedropper, and sliding the scale to 100
  • Use the spline tool to trace out the airfoil shape
    • It is easier to add points first and adjust them later
    • Turning "Show Curvature" on will help you trace out the shape better, try to limit curves appearing in the middle of nowhere
  • In the same sketch as the airfoil, draw a rectangle using the corners of the existing rectangle
  • Make an extruded cut of the area surrounding the airfoil, but "offest from surface" and make the offset .01 meters.
  • Change the material to Polyurethane Foam Rigid
  • Save the part

Foamplanescreencap 4

Making the Assembly and Changing Parts

  • Create a new assembly
  • Add both the wing and the fuselage
  • When you see them together, you may notice that the wing looks pretty small (my bad) - but it's just a learning opportunity.
  • Select the wing and click "edit part"
    • Save the assembly if prompted
  • Now editing the wing in the context of the assembly, go into Insert > Features > Scale, and scale the wing by 2.5 times
  • Use the Measure tool (under the Evaluate tab) and find the side lengths of the rectangle
    • Warning! Make sure you adjust the precision to show more significant figures.
  • Edit the fuselage and create a point that is .02 meters away from the top of the plane and .15 meters away from the very front of the plane
  • Sketch the rectangle of appropriate length using that point as the top frontward corner
  • Make a cut extrude of the appropriate length
  • Mirror that cut extrude across the front plane of the fuselage
  • Make coincident mates between faces that should be touching, there should be a minumum of 3 mates
    • More info about mates should be found here: placeholder
  • Mirror the wing across the front plane of the fuselage
    • Using Mirror Components, which is under Linear Component Pattern
      • EDIT: There is a second page of the mirror components page, select "Create Opposite Hand Version" so that the wing isn't flipped

Mirrorfix

Foamplanescreencap 5

Vertical and Horizontal Tails

  • Create a new part
  • Make a .15 x .15 m center rectangle at the origin
  • Select one of the dashed lines and uncheck "For Construction"
  • Trim away until a right triangle is obtained

Foamplanescreencap 6

  • Create a tangent arc connecting the two vertices away from the right angle
  • Extrude the whole shape by .01 m
  • Change the material to Polyurethane Foam Rigid and save the part
  • Insert the part into the assembly
  • At the rear of the plane, center a .15 x .01 m rectangle
    • Use construction lines and midpoint lines as aids

Foamplanescreencap 7

  • Cut extrude the rectange by .01 m
  • Mate the tail to the hole
  • Make a new part for the horizontal tail
  • Create a .3 x .15 m center rectangle at origin
  • Create a Sketch Chamfer (under Sketch Fillet) of .1 meters by selecting one of the rectangle's long edges and its two adjacent shorter edges

Foamplanescreencap 8

  • Extrude by .01 m
  • Place a .005 m Constant Size Fillet on both the bottom and top
  • Make a sketch on one of the top surfaces
  • Create a midpoint line (parallel to the long edge) of .01 at the origin
  • Delete the coincident relationship
  • Distance it from the origin by .05 m (move the line closer to the chamfers)
  • Create a rectangle from that line to the far edge and extrude cut it
  • Change the material to Polyurethane Foam Rigid and save the part
  • Add it to the assembly and mate it

Nose

  • Create a new part
  • Change the material to the rigid foam
  • Create a center rectangle that is .1 by .075 m on the top plane
  • Select the top plane and drag it while holding down the Ctrl key

Foamplanescreencap 9

  • Set the offest distance to be .1 m
  • On this new plane, sketch a centered circle that has a radius of .02 meters or a diameter of .04 meters
  • Under features, select a loft base and then select both the rectangle and the circle
  • Mate it to the front of the plane

Rigging the Center of Mass

  • Since it is preferential to have a center of gravity a bit further forwards, we place some aluminum inside the plane
    • You can check by checking the "Create a Center of Mass Feature" inside the Mass Properties box
    • Then, in the visibility dropdown (under the eye labeled "Hide All Types"), toggle on "View Center of Mass"

Foamplanescreencap 10

  • Create a new part
  • Make a 1 inch (.0254 meter) diameter by .06 meter tall cylinder and set the material to 6061 Aluminum
  • Save the part
  • Right click the nose and find the setting to change the transparency
  • Edit the front of the fuselage and make a centered hole for the aluminum cylinder
  • Mate the cylinder to the hole using a coincident and a concentric mate
  • Change the transparency of the nose again
  • Create a sketch on the side of the fuselage
  • Create any center line connecting to top of the fuselage
  • Select the newly formed line and while holding down the Ctrl key, select the bottom diagonal edge, then add a parallel relation
  • Dimension the line to be .3 meters long
  • Set the distance between the centerline and its parallel edge (bottom diagonal) to be .035 m
    • If the line is sticking outside of the fuselage, edit the length smart dimension (.3 meters) and click "Reverse Direction"

Foamplanescreencap 11

  • Create a circle at the frontmost endpoint with a diameter of .03 m
  • Create 4 additional circles (of any size) on the centerline
  • Create an addidtional centerline that is connected to the top of the first circle and the rear endpoint of the previous centerline
  • Make all the additional circles tangent to that line
    • Ctrl click to select both the line and a circle and enable the Tangent relationship
  • Make the distance between the first two circles "=a"
  • Set the new variable as .05 m
  • Set the distance from each of the circles as ="a" (with the quotes) and it will automatically make them .05 m apart.
  • Make a cut extrude from the sketch through the entire plane

Bonus: Air Flow

We will most likely be using ANSYS for simulation purposes, but it is good to know that SolidWorks is also capable of running simulations.

  • Create a new assembly
  • Place the plane
  • Make the view normal to the nose of the plane
  • Go under "Insert Components," and "Insert Part"
  • Click on the nose
  • Create a circle that engulfs the entire plane
  • Make a boss extrude to turn the circle into a cylinder, extrude it in both Directions 1 and 2 to surround the plane
    • You can just drag the arrows/handles
  • Change the transparency so you can see the plane
  • Click "Shell" under features and hollow out the cylinder to make sure that the plane is not touching it
    • Make sure that no face is selected
  • Under the Tools menu, go into Express Products > Flow Express
  • Keep on clicking the right arrow
  • Select Air
  • For "Flow Inlet," select Volume Flow Rate, and the front inner face of the box (right click and select "Select Other" to help)
    • Increase the volume flow rate to something like 100-150 cubic inches per second

Foamplanescreencap 12

  • For "Flow Outlet," select the back inner face
  • Click the green play button
  • After it loads, increase the number of trajectories
  • For the colored bar that appears, click the maximum and minimum and choose "Reset to Plot Maximum/Minimum"
  • Click on the play button next to trajectories to see an animation
  • Disclaimer: I don't really know what the results imply, but this looks cool

Video

Timestamps:

  1. Fuselage: 0:00 - 5:30
  2. Wing: 5:31 - 11:42
  3. Assembly: 11:43 - 16:49
  4. Tails: 16:50 - 26:34
  5. Nose: 26:35 - 29:20
  6. Center of Mass: 29:21 - 36:54
  7. Airflow: 36:55 - 40:38

Production and Costs

To simplify the building process, we will suppress some features that might make the plane hard to manufacture. This feature is very useful becuase it allows you to make disables a part of the model without damaging it. Features such as an extrude or a fillet and even entire parts or assemblies can be suppressed.

Suppress

To suppress something, find it in the Design Tree, (left or right) click it, and select the icon as shown above. A good practice is to suppress from the bottom of the design tree to the top to avoid encountering dependency errors. In this model, suppressing the aluminim cylinder (and its corresponding cut extrude), the fillet of the horizontal tail, and the circles in the fuselage can greatly simplify the manufacturing process.

Sup All

Foam Fabrication

More details can be found here placeholder

To create this plane, it is likely that either scale drawings would be printed out to trace out the foam or that sketches will be reproduced with aid from the dimensions in SolidWorks

Bill of Materials

Having a CAD model can be very useful when it is time to create a bill of materials. Creating this will help the organization budget so we are financially stable.

Here is a general outline on how to create a bill of materials.

  1. Make a list of parts
  2. Determine what materials (and quantities) are needed to create the parts
  3. Find out how to purchase the materials (i.e. search online)
  4. Record findings in a table, preferably Google Spreadsheets

Using the SolidWorks model, we can see that the model is composed of six parts: the fuselage, the two wings, the vertical tail, the horizontal tail, and the nose.

We will need foam and a bonding agent, such as epoxy or polyurethane.

By using the measure tool, we can see that the max height of the fuselage is about four inches. A very good website to buy engineering materials is McMaster-Carr. After a bit of searching, we can find an appropriate foam, off-white prototyping foam. The smallest 4-inch thick foam sheets are 24 inches wide by 48 inches long.

Using SolidWorks, we can see that the entirety of the foam components can be made out of this sheet.

Foamfit

This means that we can save money by purchasing one sheet of foam for the entire plane.

When making a bill of materials, it helps to keep track of the status of the part

References