The Flying Slug


The "Flying Slug" was designed to compete in the 2005/2006 AIAA/Cessna/ONR Design/Build/Fly contest, held in Wichita, KS in April of 2006.  The aircraft was optimized to perform a combination of Cargo Flexibility, and Minimum RAC missions.  In the cargo flexibility mission, aircraft are alternately loaded with 48 tennis balls, 4 Liters of water, and a 4inx4inx24in wood block as fast as possible.  The minimum RAC mission required the aircraft to fly 96 tennis balls around a prescribed course.  Flight score for this mission was entirely based on having the lowest empty weight possible.  The Flying Slug was named for the resemblance of the fuselage to a slug, and because the slug is the true unit of mass measurement.  The Slug finished in second place at the contest.

Specification List: 


  • Wingspan:        6.14 ft
  • Wing Area:       4.72 sq ft
  • Aspect Ratio:    8
  • Airfoil:               SHaWn001XLSE (Custom designed)


  • Length:        4.16 ft
  • Diameter:     8.5 in


  • Motor:         Hacker B50-13S Geared 6.7:1
  • Controller:    Hacker Master 48-0
  • Fuel:            14xGP 2000 NiMH
  • Propeller      18 in


  • Empty Weight (Without batteries):    3.9 lb
  • Battery Weight:     1.2 lb
  • Payload Weight:    9.6 lb max (2x2L water bottles)
  • Gross Weight:       14.7 lb


  • Lightweight composite molded construction
  • Custom designed and built main and nose gear
  • Speed loading/unloading system
  • Magnetic/clasp payload bay speed latch
  • No setscrews


  • Take off at gross weight (GW):    100 ft.
  • Max climb rate (GW):    15 ft/sec
  • Stall speed (GW):         40 ft/sec
  • Maximum speed:           87 ft/sec

Speed loading System

The speed loading system was critical to the success of the Orange Team since the mission 1 flight score depended entirely upon how quickly the payloads could be changed out.  The system developed for the slug was based on cylindrical containers.  Each was optimized for the particular payload.  The tennis balls were the most challenging payload since 48 balls had to be dumped from a bucket into the loader.  The system used by the orange team was a funnel connected to a cylinder of optimal diameter so that the balls would load the same way every time.

Team Info: 

The OSU Orange design team was led by a Chief Engineer, and divided into three primary groups: Aerodynamics/Stability and Control, Propulsion, and Structures.

Chief Engineer: Karalyn Eyster

Aerodynamics / Stability and Control:

  • Marcus Hershberger (Lead)
  • Shawn Hellman
  • Aya Nakae
  • Jennifer Newlin


  • Pamela Cates (Lead)
  • Kah Boon
  • Aaron Gilmore
  • Joseph Pruitt


  • Mike Rumbaugh (Lead)
  • James Cullin
  • Erika Ennis
  • Clinton Grell
  • Dustin Gamble
  • Richard Henry
  • Thomas Hays
  • Jeremiah Johnson
  • Lloyd Krueger
  • Justin Shaner
  • Kenny Sharp
  • Gentry Shelton
  • Travis Watson

Pilot: Dan Bierly

Spotter: Jeremiah Johnson

Pit Crew:  

  • Erika Ennis
  • Marcus Hershberger
  • Kenny Sharp

Faculty Advisor: Dr. Andrew S. Arena, Jr.


  • Joe Conner
  • Robert Fischer
  • Matt Adair
  • Atith Kotcherlakota

*(The above team roster does not include all people involved in the project)

Contest Summary: 

The 2006 DBF contest, three missions were available for the teams to fly: Cargo flexibility in which aircraft are alternately loaded with 48 tennis balls, 4 Liters of water, and a 4inx4inx24in wood block.  Score for this mission was based on the pit stop time.  The minimum RAC mission required the aircraft to fly 96 tennis balls around a prescribed course.  Flight score for this mission was entirely based on having the lowest empty weight possible. Finally, the Incremental payload mission where the aircraft starts with 2x2 Liter bottles of water, and a bottle is added for every lap.  Score for this mission was based on the total amount carried.  The Flying Slug was optimized to perform The Cargo Flexibility mission and the minimum RAC missions.

Overall score was the sum of the two best flight scores, multiplied by the written report score, and then divided by Rated Aircraft Cost (RAC).  RAC for 2006 was simply the aircraft empty weight including batteries, so having a very light and efficient airplane was essential for success.

Major design constraints:

  • The aircraft had to fit disassembled into a 4 ft x 2 ft x 1.25 ft box.
  • 100 ft runway (The shortest runway used by the DBF contest)
  • Electric motor, and NiMH, or NiCd batteries required

To begin the contest on Saturday morning, the OSU teams were in first and second place based on the ratio of flight score to RAC, and were first in line to attempt a flight.  The Orange team attempted mission 2 however a fluke accident handling the aircraft in preparation for the second lap resulted in tail damage that had to be repaired before another flight attempt.  By the time the repairs were made and the team had waited in the queue, several other teams already had more than one flight score, and there was time enough for only one more attempt for the Orange team.  The team switched strategies to fly mission 1, and scored the best time of the contest.  In fact, the score was high enough that it put them in first place with only one mission flown.

On Sunday, the Orange team was prepared to perform mission 2, and try to put themselves out of reach by all but the OSU Black team.  On the second lap of the mission, the airplane mysteriously ran out of power, and crashed on the runway.  The damage was repairable, and the structures team spent the next couple of hours making the plane flyable again.  During that time the Black team had completed their second mission, and was untouchable in first place.  Another team had moved into second place, dropping the Orange team to a close third.  With Only 20 minutes left in the contest, the Orange team was ready to fly again, and had to make a decision; attempt mission 2 and finish a close second to the Black team, or fly a single lap of mission 3 which they calculated would give them just enough points to move in to second.  Since the latter option was less risky as it only involved one lap, that was the option chosen.  Ironically the Slug was not optimized for mission 3, and the team never thought they would need to fly it.

Complete Contest Rules

Official Results

Results Summary: 

Report Score:      96  (Highest at the contest)
Pit Time:             44.19 seconds (Fastest at the contest)
RAC:                   5.1
Total Score:         790
Overall Place:      2nd


The following sponsors contributed to the project.  The OSU Orange team greatly appreciates their support, and considers them members of our team.  Without their support, the project would not have been possible.

Ray Booker
Lockheed Martin
Public Company of OK
Rodger’s Consulting Inc.
R.G. and Nancy Rumbaugh
Frontier Engineering
L3 Communications – Tulsa
Papa John’s Pizza
Mark and Ann McWatters
Garry and Melanie Gilmore
Jaria Gilmore
Tom and Gena Christensen
Adam and Kassie Gilmore
Ditch Witch


Design, Build, Fly