1. Trebuchet Basics
Fritz R. Fiedler

2. Basic Sling Trebuchet

3. Example Frame

4. Example Beam

5. Example Tip Detail

6. Release

7. Trigger

8. Sling

9. Basic Trebuchet

10. Basic Trebuchet

11. The Throw

12. Definitions v0 a h

13. Energy Equations

14. Range

15. Efficiency
What affects efficiency and what would you expect the actual efficiency to be?

16. Efficiency Does not include effects of: mass of beam friction
air resistance …?
Efficiency ~ 50% or less
(compute for report!)
so Rm < hm1 / m2)

17. Required Information h : by design m1 : by design
m2 : given – how computed?

18. Projectile

19. Example Simple Calculation
assume: h = 4 feet
m1 = 100 lbs
given: m2 = 4.1 lbs
R ~ 98 feet

20. Design Flexibility
What aspects of the trebuchet can be varied (after primary construction) to change throw distance?

21. Design Flexibility Counterweight mass (m1) h: sling length
fulcrum height
starting position
beam length – how?
sling length
release angle

22. Counterweight Design Constraint: must fit in 5-gallon bucket.
What materials might be appropriate?

23. Counterweight 5 gallons = 0.67 ft3 water: 62.4 lb/ft3
sand (dry): ~110 lb/ft3
sand (saturated): ~135 lb/ft3
concrete (ordinary): ~ lb/ft3
steel: ~490 lb/ft3
lead: ~710 lb/ft3

24. Other Considerations Will it tip over? Will the beam break?
Will the sling snap?
Will the throw be straight?

25. References