Bronze Propeller Competition

Besides being attentive to traditional technical work, engineers must also consider public health, safety, and welfare in everything we do. Coincident with this aspect, we need to be mindful of global, cultural, social, environmental, and economic factors. Students often lose touch of the fact that "engineering is not done for its own sake, it is practiced in context" (McMasters & Cummings, AIAA Journal of Aircraft, Vol. 41, No. 1, January–February 2004). 

In summary, young engineers need to be curious of the competition, making connections between the knowledge they have learned and creating products of value. These expectations are an important part of the competition and a foundation for success as a professional engineer.

For the 2025 Boeing Bronze Propeller competition, each team needs to design, build, and fly a fixed-wing vehicle that performs a challenging engineering task and creates unique market value that contributes to Urban Air Mobility (UAM) Tasks.

The vehicle to be designed, built, and flown must be capable of taking off and landing on a short off-ground platform (16 ft in length, 8 ft wide, 4 ft off the ground) and carry payloads (represented by small glass easter egg [2 oz], the egg has a width of 1.5 inches and height of 2.5 inches) that add unique market value to the current UAM market. There are two mission profiles that can be chosen from:

1. Payload Dropoff (10 ft x 10 ft Dropoff Zone) and Return.
2. Landing at ‘conventional runway’ (50 ft & Ground Takeoff), Payload Pickup and Return.

As part of the competition, each team needs to come up with its own specific mission that creates value for the current UAM market. This proposed mission must be effectively explained in a well-written abstract. External judges will review and score the abstract prior to competition day by considering at least one of the following values:

• Community health.
• Public safety.
• Public well-being or prosperity.
• Impact on a world-wide scale.
• Lifestyles, occupations, religion, wealth, and educational attainment.
• The environment benefits.
• The economy benefits.

To boost your competition score, you can address as many of these values or marketability aspects as possible. The abstract can be viewed as a “sales pitch” to secure approval/funding from your management, government agencies, or private investors. Your airplane configuration should support your mission definition.

Additional abstract judging criteria include:

1) Uniqueness – what can your design provide that differentiates you from other concepts?

2) Meaningfulness – who is your target customer that can benefit from your design?

3) Investment Return – will your design retain market share/value and benefit your investor?

The abstract score will directly impact your competition score.

• Fly within an indoor or outdoor area roughly 100 x 150 ft in size.
• Take off and land safely from the short platform (16 ft in length, 8ft in width, 4 ft off the ground)
• The airplane should have a minimum flight time of 120 seconds and finish a total of 2+1+2 = 5 circles on the flying field.
• For Mission A, the team needs to drop off the payload in a square payload drop-off zone with a 12 ft diameter.
  • Airborne Dropoff: Each team is allowed to drop off their payload in multiple passes.
  • Scoring payload must 'touch down; within the drop zone.
  • 1 point penalty will be added for missing the drop-off zone.
• For Mission B, the team needs to land on a ‘conventional runway’ (50 ft) and reload the aircraft. The aircraft then needs to ground takeoff from the runway.
  • Manually reload: After engine shutoff on the conventional runway, each team has 30 seconds to manually reload the aircraft. The timing starts when the team enters the runway area.
  • Auto-reload (5pt bonus): After the aircraft lands on the runway, the team has 2 minutes to pick up the payload without any manual operation other than pilot's input.
  • A ground infrastructure is allowed for Mission B on the conventional runway. However, the ground infrastructure cannot be remotely controlled.
  • Scoring payload must be attached to the vehicle and undamaged after landing.
• A 24x12 ft backup ground runway will be located next to the STOL platform. The team can choose to land on this ground runway with a penalty of 2 pts.
• Crash landing on the STOL platform or backup runway (including runway overruns) will result in a penalty of 3 pts.
• A maximum of eight (8) total payload is allowed.
• Bonus Operation: Capable of flying at least two additional “figure-eight” patterns with full payload (3 pts) or empty payload (1 pts).
• Payloads are represented by glass easter eggs filled with beans to reach 2 oz/each. The size of the easter egg is approximately 50 mm x 30 mm.
• Protection of the payload is allowed. However, payload protection must be installed on-field within the time limit. Only the number of undamaged payloads will score in the competition.
• Ground infrastructure that helps takeoff and landing on the STOL platform is allowed. Each team has 120 seconds to install the Ground infrastructure, load the payload, and set up the vehicle takeoff configuration before the competition. Permanent mounting (including but not limited to screwing to the runway, gluing to the runway, etc.) is NOT allowed. Any ground infrastructure cost is included in the vehicle's total cost.

1. The aircraft must be 100% conceived, designed, and built by the team members.
2. A thin plastic wrap (or equivalent) over the payload easter-egg is required for safety concerns.
3. Teams are required to register and submit a mission description abstract by March 31^st (see Registration & Abstract section below).
4. The vehicle must be a fixed-wing airplane (no rotorcraft, lighter-than-air, etc.).
5. Only a WSU-designated test pilot will fly the airplane.
6. Each team has guaranteed three (3) attempts for the competition, and the highest score will be recorded for final score calculations. Additional attempts might be available if time permits.
7. Flights without returning to the landing platform will not receive any mission score (excluding landing accidents which will result in penalty points).
8. Aircraft can be repaired and flown again between each mission attempt, as long as all rules are satisfied.
9. Tape is only allowed for on-site repair during the competition.
10. Critical systems and components must be firmly mounted and quickly accessible.
11. Aircraft changes during the competition that deviate significantly from the initial design configuration are not permitted.
12. A maximum of six (6) control channels are allowed.
13. A maximum of two (2) ESC, Motor, and Propeller assemblies is allowed.
14. All servos must be secured and mounted (no Velcro, tape, wire, or adhesive mounting).
15. Undergraduate teams have a $600 total budget to purchase all supplies for vehicle building, ground infrastructure, and related testing equipment.
16. WSU-supplied materials should be considered first. Discounted pre-owned material is available for the first-come-first-get principle.
17. For all WSU student teams, accurate team records and receipts are required by competing teams. A monthly audit is required for each team. Any external purchase greater than $10 must be approved by the instructor.
18. Battery packs must be off-the-shelf purchases and cannot be modified (except for connectors)
19. A short circuit fuse (XT-60) must be installed to each on-board battery.
20. An ESC with a minimum of 1.25 times the motor peak current must be paired with the motor. (i.e Peak 30A motor should paired with an ESC rated for 37.5 A)
21. The paired battery discharge rate should be at least 1.5 times the maximum motor peak current.
22. Teams can have multiple batteries ready for use during the competition day. However, all batteries must be identical (i.e., of the same manufacture, type, voltage, and milliamp-hours).
23. Teams assume all responsibilities in assuming servo, ESC, motor, etc. compatibility.
24. Teams assume all responsibilities in assuring propellers properly mount to the motor.
25. The plane’s wingspan is limited to a maximum of 40 inches.
26. All undergraduate design teams must incorporate a WSU 3x4-ft wind tunnel ATI Nano-45 6-axis balance mounting capability.
27. The use of heat shrinks, or tissue coverings is allowed.
28. The use of foam is allowed. However, the foam used cannot exceed 30% of the wing, tail, or fuselage volume.
29. The spar and stringer of the airplane’s wing / tail are encouraged to be made of wood. The spar of the wing could be built out of composite material, but the diameter of composite material cannot reach 3/8 inch or 9.5 mm OD.
30. The in-house building and machining of any fiber glass or composite material is NOT allowed. Those materials should be used ‘as purchased’ on your design. If machining is absolutely necessary, you need to have permission from Dr. Cai and the machining has to be done by a professional source.
31. 3D-printed components are allowed. However, materials are limited to PLA or tough PLA. Printing costs should be included in your total vehicle cost as well.
32. Use of any compressed air, high voltage (max 24V) or high temperature (i.e. steam) component for the ground infrastructure is NOT allowed. Any other design with safety concerns could be disqualified from the competition if the team did not communicate with Dr. Jacky Cai.
33. Planes cannot be flown unless all team members are in a designated safe area.
34. There is no default or automatic win if there are three or fewer team category entries.
35. In the spirit of the goals of the competition, all rules, requirements, constraints, and scoring aspects are subject to interpretation and change by Dr. Jacky Cai.
36. Have fun!

There are three participant categories:

• WSU Undergraduate (1^st Place $3,500, 2nd Place $2,500, & 3^rd Place $1,500)*
• High School and Professional (1^st Place $500, 2nd Place $250)*

* Note: Prize money is not automatically awarded when there are a small number of entries in a certain category. Teams must complete the mission and score 8 pts in the competition to be consider for prize money.

Teams with an alumni, past AE 628 student, or graduate student member must participate in the professional category. High school or undergraduate teams cannot elect to compete in the professional category (unless team members scored in the top-three in a previous competition).

Don't be shy. Form a team, build a plane, and fly!

Mentors for high school and undergraduate student teams are recommended. Feel free to contact Dr. Jacky Cai (jielong.cai@wichita.edu) or Dr. Suresh Raju (suresh.keshavanarayana@wichita.edu) for help finding a mentor, borrow critical airplane components, work in the PPL lab, and secure supplies.

The following competition scoring equation applies:

Score = (1+2 * n_p) * AEF * PV * HQ – Pen + Bonus

Where:

• n_p is the number of payloads dropped or returned without damage.
• AEF is the Aircraft Efficiency Factor and is defined as:

AEF= (W_e)^-0.3 * (nb*V * P)^-0.05

• W_e are aircraft empty payload weight in lbs. (including battery and all electronic)
• nb is the number of batteries.
• V is the manufacturer-rated voltage of the battery
• P is manufacturer-rated battery capacity in Amp. h.

• PV is the product value, determined by the faculty and external judges during the competition day.
  • PV values range from 0.75 to 1.25, calculated based on the average score from each judge and normalized by the mean and standard deviation of the entire scoring sample.
  • PV is evaluated based on the team’s project pitch and brochure design. Four criteria are used for judging the PV:
    
    • Mission and Design Uniqueness. 
    • Mission Meaningfulness and Value Created.
    • Technical Information and Brochure Quality.
    • Professionalism and Design Build Quality.
• HQ is the aircraft handling quality, judged by the pilot during the competition day.
  • PV values range from 0.75 to 1.25. The average of the top two scores will be used to determine the scoring of HQ. It is then normalized by the mean and standard deviation of the entire scoring sample.
  • The pilot will score each flight using the following criteria.
    
    • Takeoff and landing performance.
    • Maneuvering and turning performance.
    • Overall aircraft handling sensitivity.
• Pen is the penalties incurred by the team during the competition, which includes:
  • Crash landing on the STOL platform or backup runway (including runway overruns) will result in a penalty of 3 pts.
  • Landing on the 24x12 ft backup runway will result in a penalty of 2 pts.
  • For Mission A, payload missed the drop-off zone will result in a penalty of 1 pt.
  • 1 pts penalty for every 10 seconds of additional time during takeoff preparation and payload loading process.
• Bonus is the bonus maneuver completed by the team, which includes:
  • Capable of flying at least two additional “figure-eight” patterns with full payload (3 pts) or empty payload (1 pts).
  • Auto-reload (5pt bonus): After the aircraft lands on the runway, the team has 2 minutes to pick up the payload without any manual operation.

• Crash landing is defined if one of the following conditions occurs.

  1. Landing upside down.
  2. Runway overrun and not stopped on the platform.
  3. Landing with a major component broken and the aircraft is not flyable with these broken components. The major components include the wing, fuselage, tail boom, and tail.
• Note: The airplane skin, landing gear, control surface, and propeller are NOT defined as major components. Small scratches or a small number of broken ribs that do not affect the aircraft's overall performance will not count as a crash landing.

Teams will be disqualified for their flight attempt if they significantly delay or adversely impact the competition. Specifically, a penalty will be given if:

• The plane leaves the designated flying area.
• The team, in any way, significant delays the competition.

The team can scratch or abort a flight attempt before entering the flying area without a penalty. Be certain your plane is 100% ready to fly before you get into the flight area.

It’s critical to respect competitor plans for multiple flights during the event. Teams that significantly waste time will be disqualified for their current flight attempt.

The sad reality is that crashes happen. However, keep in mind that many teams can quickly repair and fly their planes again. Never give up!

Teams that suffer a crash will not be disqualified unless they unduly delay the competition (e.g., take too long to recover their plane from the flying area). In some cases, teams may be required to wait to recover their crashed aircraft, for safety or other reasons.

Hard landings, with damage, are very common. In such a case, a mission score will not be recorded. Damage that requires more than 30 minutes to repair is considered significant damage and will result in a team disqualification.

A maximum of one additional scoring attempt will be awarded for a team that experiences a minor crash and has not scored any scoring flights after their last regular attempt.

Teams are required to register for the competition and, at the same time, to submit their Mission Description Abstract. The process is easy, simply complete the form and email it to Dr. Jacky Cai. The deadline for this document is March .

The Mission Description Abstract should specifically address elements discussed in the Background section. The abstract must fit within the allocated space on the form (with an unchanged 12-pt font and 1-inch margins).

Although we really want you to compete, there is no commitment associated with registering.

Competition day is scheduled for 11:00 am - 4:00 pm Saturday, May 3rd, 2025.

Flight Entry: Before entering the competition, each team will first get in the queue line. There will be five queue line tables during the competition day. The first table will be the control check table operated by Jacky. The second table will be the weight station operated by Quang. Each team has 3 priority flights, meaning that if your team has less than 3 flights, you can get in to the queue line anytime. If your team has already completed three flights, you can still get in the queue line, but any team that has completed fewer than 3 flights can jump in front of your team at any time.

Any team that was removed from the flight area (excluding the queue line) due to a lack of readiness (taking too long to set up or being removed by the instructor due to any other reason) will lose the current flight attempt and score a zero point.

When two hours are left in the competition (at 2:00 pm), teams without a successful scoring flight will be given flight-line priority.

Weight Station: A student competition assistant will be weighing all airplanes before entry. We will check your payload weight first and make sure that each egg weighs 1.25 oz minimum, so for all 8 payload, your egg weight should be at least 10.0 oz. Then we will weigh your airplane using 2 scales. All components, excluding the payload, should be weighed. This includes any additional wrapping and protection of your payload. If your wrapping is difficult to remove during the competition day, we will account for each of your payloads as 1.25 oz and weigh it with the aircraft, then subtract the weight of the payload.

Control Check Station: The instructor will operate the control check station and give final approval for the team to enter the flying area. Jacky will make sure all control surface operates as desired before the flight. After the control check, the team can leave the battery on. Jacky reserves the right to reject any team's entry or remove the team from the flight area if the team is determined as not ready.

Timing: A student competition assistant will record the timing during the competition. For the takeoff setup, the timer will start when the team touches the short takeoff platform or a 50ft conventional runway (for auto pickup setup), whichever occurs first. So I would recommend the team start on both runways together if necessary. A 30-second left warning will be provided to the team. After the 2-minute time limit, the team will be notified, and a penalty will be imposed for every 10 seconds of additional time used. If the team fails to set up within 3 minutes, they will be removed from the flight area.

Payload Pickup: For manual payload pickup, the timing will start when the team touches the airplane on the runway. The team cannot touch the plane until the team receives permission from the pilot. The team has 30 seconds to load the payload manually.

For the auto payload pickup, the timing will start when the airplane lands on the runway and reduces to taxi speed. The timing will stop after the payload is loaded and the airplane starts to taxi for takeoff. If any team member touches the airplane during the auto payload pickup, it will be considered as manual payload pickup. The team can request to switch to manual payload pickup if the auto payload pickup attempt fails. The team then has 30 seconds to manually load the payload into their airplane.

Product Value Judging: Judges will walk around each team's table to talk to each team during the competition. Each team should prepare a 2-3-minute elevator pitch for your project and provide your brochure to the judges. The judges might come in groups or individually, so please be prepared to pitch your project multiple times. All PV judging will end around 12.30 p.m.

Final Score: Depending on the competition day, the final score and winner might not be announced on the competition day. The score will be available on Monday after the competition and will be posted on the Bronze Propeller Website. Award and competition certificates will be presented to the team during the Engineering Open House. Teams should work with Dr. Raju for the prize money transfer after the week of the Engineering Open House.

Technical Feedback: Due to the nature of the competition, the instructor and the pilot will not provide any technical feedback or suggestions to the team's design. The pilot will only provide qualitative feedback on how the airplane feels during the flight, and the team is prohibited from asking for improvement suggestions during the competition.

Crash and Disqualification: Teams that suffer a crash will not be disqualified unless they unduly delay the competition (e.g., take too long to recover their plane from the flying area). When a crash occurs, a mission score will not be recorded, except for a crash landing on the runway, which results in a penalty. Any damage that requires more than 60 minutes to repair is considered significant damage and will result in team disqualification. Such a crash disqualification is determined by the instructor after the crash.

• What's preventing teams from simply copying and pasting (or adapting) a mission for a team last year? 
  Using or even slightly modifying previous mission ideas or abstracts is plagiarism and will result in a zero score or disqualification.
  
• Can teams make their own payload?
  No – the payload are supplied at the competition.
  
• Will the size and weight of the payload be checked?
  Yes – the payload each team wishes to carry will be weighed at the competition.
  
• Are subassemblies, like a premade wing with control surfaces installed, but not assembled to the fuselage allowed?
  Yes – subassemblies are allowed, but the cost should be included in the budget and cannot exceed the maximum budget allowed.
  

Additional Information or Questions

Contact Dr. Jacky Cai with any additional questions.

For the 2024 Boeing Bronze Propeller competition, the team need to design and build a vehicle that performs a challenging engineering task and has market value.

The vehicle to be designed, built, and flown must transport removable “tanks” containing liquid. The tanks are represented by two 20 oz. plastic Gatorade bottles. Further details on the payload are presented in the rules and requirements section. 

As part of the competition, each team needs to invent a context within which their vehicle has broad and ideally, marketable value. This supposed mission must be effectively explained in a well-written abstract. External judges will review and score the abstract prior to competition day by considering the following:

“Does the product have a favorable impact on?”

• Community health
• Public safety
• Public well-being or prosperity
• A world-wide scale
• Different cultures
• Lifestyles, occupations, religion, wealth, and educational attainment
• The environment
• The economy

To boost your competition score, you need to address as many of these values or marketability aspects as possible. Although, the “tanks” will contain water for the flight competition, you may assume the “tanks” contain any type of liquid you want to support your mission definition. Do a good job both inventing and communicating your mission. The abstract can be viewed as a “sales pitch” to secure approval/funding from your management, government agencies, or private investors. Your airplane configuration should support your mission definition. Some things to keep in mind: 1) know your competition – why is your product a better value, 2) investors expect a good return on investment – why will customers buy your product, 3) what is your target customer base. There are other considerations as well. Don’t limit yourselves. The “perceived value” score that you receive from the judges on your abstract will directly impact your competition score.

The following competition scoring equation applies:

Score = (1 + 16 * W_p) * AEF * PV  - 5 * P

Where,

• W_p is payload weight in lbs (weight of total water carried)
• AEF is the Aircraft Efficiency Factor and is defined as:

AEF= (W_e)^-0.2631 * (1.1-N_m* 0.1) * (1.1 - N_s* 0.05) * (V * mAh/1000)^-0.05

• W_e is aircraft empty weight in lbs (take-off weight minus W_p)
• N_m is total number of motors
• N_s is total number of servos
• V is manufacturer-rated voltage of the battery
• mAh is manufacturer-rated milliamp-hours of the battery
• PV is the product value, determined by the external judges’ review of the mission abstract (values range from 0.8 to 1.2 and are determined prior to competition flight day).
• P is total number of penalties incurred by the team during the competition

Teams may conduct multiple flights to try to improve their score. The highest single-flight score will be the score of record. Note that the payload weight (W_p) is the only scoring element that can be varied on flight day to improve score.

The contest included:

• 10 teams

For the 2023 Boeing Bronze Propeller competition, you need to design and build a vehicle that performs a challenging engineering task and has market value.

The engineering part of the competition is relatively simple. The vehicle needs to be light, quick to build, and drop a payload accurately.

Additionally, you need to invent a context within which your vehicle has broad and, ideally, marketable value. Then you have to effectively explain the mission in a well-written abstract. External judges will review and score the abstract prior to competition day by considering the following:

    “Does the product have a favorable impact on?”

• community health
• public safety
• public well-being or prosperity
• a world-wide scale
• different cultures
• lifestyles, occupations, religion, wealth, and educational attainment
• the environment
• the economy

To boost your competition score you need to address as many of these value or marketability aspects as possible. Do a good job both inventing and communicating your mission.

The contest included:

• 12 teams, 11 undergraduate and 1 professional
• 81 flights or attempted flights
• An average MAT of 72
• An average PV of 5.3
• An average Wo of 0.91 pounds
• 5 planes with Wo less than 1.0 pound
• 18 target HITS, by 5 teams
• 2 teams had 6, or more, HITS each
• The winning undergraduate team scored HITS on 60% of their flights
• The winning professional scored HITS on 73% of their flights
• 35 payload drops that missed the target
• Only 2 penalties assessed
• A great crowd, of faculty, staff, students, friends, and family