1 / 21

A Pumpkin in Flight

A Pumpkin in Flight. Eric Lehnhardt & Wade Gyllenhaal Honors Project, Physics 121. The Punkin’ Chunkin’. Delaware countryside First weekend in November Post Halloween Kid’s Division, Adult’s Trebuchet and Adult’s Cannon Divisions www.punkinchunkin.com. Air Cannons. Highest-achieving

cain-wilson
Download Presentation

A Pumpkin in Flight

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. A Pumpkin in Flight Eric Lehnhardt & Wade Gyllenhaal Honors Project, Physics 121

  2. The Punkin’ Chunkin’ • Delaware countryside • First weekend in November • Post Halloween • Kid’s Division, Adult’s Trebuchet and Adult’s Cannon Divisions • www.punkinchunkin.com

  3. Air Cannons • Highest-achieving • Weight in excess of 14 tons • Barrels of varying length • World-Record Holder “Second Amendment” has barrel length of approx 100 feet, or 30 meters

  4. Analysis

  5. Analysis

  6. Excel Sheet • Frame by frame analysis • Use of t-Step • Use of variables • Determine key variables like mass, density, coefficient of drag, and velocity • A Pumpkin in Flight/Pumpkin Motion V3.xls

  7. Problems • Error in sign • Use of sine and cosine functions became tricky once the pumpkin moved past its apex • Substitution of (v_x/v) and (v_y/v) • Proper range • t-step size (0.2 to 0.01s added 200m of distance) • Drag coefficient (0.44 for spheres, but pumpkin has ridges, similar to golf balls and their dimples) • Density of pumpkin (varieties, gourds) • Too many variables

  8. Likely Solutions • Aimed for Second Amendment record of 1,366 meters • Known initial velocity of 500mph ≈ 203 m/s • Case One – small drag coefficient • C_d = 0.2 • M = 10 kg • R= 0.15 m This pumpkin has the dimensions and density of a typical store-bought pumpkin, such as used for jack-o-lanterns (verified at the local Safeway’s)

  9. Likely Solutions • Case Two – adjusted sphere drag coefficient • C_d = 0.3 • M= 15 kg • R = 0.15 m • This pumpkin is denser than average (it weighs close to 35 pounds) and may more likely be a gourd or “white pumpkin”

  10. Likely Solutions • Case Three – sphere drag coefficient • C_d = 0.44 • M = 23 kg • R = 0.15 m • This pumpkin is very dense (weighing approximately 50 pounds) and begins to approximate a cannonball

  11. Forces on Pumpkin

  12. Things to Consider • Possible tail winds • Initial height of the cannon • Elevation change in the testing field • Density of air in Delaware (elevation, temperature) • Magnus Effect

  13. http://www.youtube.com/watch?v=B4JUZHiiNWQ

More Related