SCTC 2017 PROBLEM SOLVING – Siege Machine Design
OVERVIEW
Participants will use their skills in problem solving to develop a finite solution to a stated problem. Participants will work as a
team to provide the best solution, which is measured objectively.
CHALLENGE
Working as a member of an engineering design team (2-3 members from your school), design and construct a working
ballista, catapult, or trebuchet, within specified guidelines, that is adjustable and propels hollow plastic practice golf balls
(weighing about 14.5 grams each) at a scoring target between 15' and 25' away.
ELIGIBILITY
Teams are limited to three members.
LIMITATIONS
To complete this engineering design activity successfully, your team must adhere to the design parameters outlined below.
Failure to observe these parameters may cause your team to be disqualified.
1. Schools may have multiple engineering design teams entered in this contest, but each team should not include
more than three members from the school;
2. The completed device must:
a. The device may be no larger than 4' tall x 3' long x 3’ wide.
b. The base of the device should accommodate the provided ballast. The
ballast will be one (1) 50-pound bag of playground sand, provided on site.
c. The device must operate completely within the given area; the launch arm may extend beyond the
front of the device only while launching.
d. The device may have any type of spring mechanism to power the arm, but all parts must be contained
within the 4' tall x 3' long x 3' wide maximum footprint prior to launch.
e. The device’s total weight must not exceed (15) pounds.
f. All parts of the device must initiate behind the launch line, but parts may extend over the line during and
after the last launch.
g. The device cannot have wheels.
h. The device must be made entirely from PVC pipe, with the exception of the launch mechanism, firing
mechanism, fasteners, and safety items. These items may be wood or metal and must be
constructed in a safe way, so as not to damage the device, the testing area, or cause harm to others.
i. The following may not be used:
1. Glass
2. Flammable, corrosive, or explosive materials
3. Compounds that produce odors or gases
i. The device must have at least a five (5)-foot pull cord to launch from a safe distance.
j. Participants must bring and wear safety goggles during the performance stage of the event.
3. Additionally, teams should submit an engineering journal that outlines the design process used to construct the
device.
4. One member of the engineering team should be prepared to briefly discuss the design of the team entry prior to
testing;
5. All rulings of the contest judges during the event will be final.
TIME LIMITS
The device must be completed prior to the 2017 SCTC.
PROCEDURES
1. Teams will receive a bucket of three (3)-dozen hollow plastic practice golf balls (each weighing approximately 14.5
grams) for the performance stage.
2. The team will be given three (3) minutes to adjust the device for accuracy to the determined distance.
3. Teams will position their device on the "firing line" and wait for the command to fire.
4. When teams receive their bucket and the fire command is given, they will have one (1) minute to launch as many
hollow plastic practice golf balls as possible to accumulate as many points as possible in the net. Each team must
cease firing at one (1) minute. No shots made after time has been called will count.
5. The center of the scoring net (red circle) will be approximately 15' from the launching area. The scoring net will
consist of a golf chipping target and three (3) color-coded scoring sections. The red center target is 10" in diameter,
the green is 25" in diameter, and the blue target is 40" in diameter.
6. Scoring is as follows: red target, 5 points; green target, 2 points; blue target, 1 point.
7. Hollow plastic practice golf balls must enter the target on the fly and be fully in the scoring net to score points. No
points will be earned for bounced-in or half-in/half-out hollow plastic practice golf balls.
EVALUATION
SIEGE MACHINE DESIGN
SCTC 2017 PROBLEM SOLVING
Siege Machine Design Specifications Compliance Go or No-Go
A device that is marked No-Go for any of the requirements below will not advance to the performance stage of the event.
Team members must have safety goggles.
Go
No-Go
The device can be weighed down with a sand bag.
Go
No-Go
The device is the correct size.
Go
No-Go
The device is built with the correct materials.
Go
No-Go
The device launches with a pull cord.
Go
No-Go
The device has a safe launching mechanism.
Go
No-Go
The device is safe to operate.
Go
No-Go
SUBTOTAL (50 points)
Device Performance
# Hollow Plastic Practice Golf Balls
Score
Red target - 5 points each
Green target - 2 points each
Blue target - 1 point each
PERFORMANCE TOTAL
The team with the highest performance total of points wins the contest. Solution designs will be used to break ties. Only as
a last resort does the event coordinator use subjective measurement, such as originality or aesthetics, to evaluate solutions.
Please complete following information and submit with your final design to the contest site.
2017 SCTC Problem Solving
☐ LEVEL I
☐ LEVEL II
School Name
_________________________________________________________
Team Members
1. ________________________
2. ________________________
3. ________________________
Total Points: ________________________
Red target - 5 points each - Green target - 2 points each - Blue target - 1 point each