1. Redesign of the STOL CH 701 Landing Gear Strut
Group Members: Peter Chiu
Cameron Clark
Dave Maharaj
Okason Morrison

2. Problem Definition
Design a single-piece double cantilever leaf spring capable of surviving the landing conditions set forth by the FAR.

3. Specifications Descent velocity range
ft/s (2.134 m/s m/s)
Descent load factor range
1.67g – 2.67g
Wing Area
122 ft2 (11.2 m2)
Empty Weight
580lbs (263 kg)
Gross Weight
1,100 lbs (500 kg)
Payload
520 lbs (236 kg)
Max Reaction Load on tire
1350 lbs (6005 N)
Tire Diameter
16 in (0.406 m)

4. Theoretical Analysis 1: Newton’s Equation of Motion

5. Assumptions Plane can be treated as point mass
Constant deceleration (vertical component only)
Neglecting material properties
Plane has zero final velocity

6. Calculations sstrut stire
The displacement, s is a function of 2 variables: u & a
sstrut = f (u, a) surface plot

7. Maximum Displacement: 3-d
S is max at
a =1.67g
u= 10 ft/s
Sstrut(max) = 212 mm (8.36 in)

8. Theoretical Analysis 2: Beam Deflection

9. Geometry Simplification
Strut can be modeled as a cantilever beam
Only a portion of strut needs to be analyze due to symmetry
Beam subjected to 1 load and 1 moment X Y Ry  M
R = 1350 lbs

10. Deflection Equations

11. Deflection Equations 2 h b

12. Beam Analysis
Width
Suitable strut width  65 mm (2.6 in)

13. Finite Element Analysis

14. Modeling
Material: Al 2014
σyield: 414 MPa

15. Optimization Study

16. Engineering Drawings of Final Design

17. Deflection Video

18. Deflection
Sstrut(max) = 45 mm (1.77 in)

19. Von Mises Stress
σvm: 307 MPa S.F. = 1.3

20. Summary Table Material Al 2014 Strut Width 120 mm Strut Height 354 mm
Strut thickness
17 – 20 mm
Max Strut Deflection (Newton’s Law)
212 mm
Max Deflection (Beam Analysis)
111 mm
Max Deflection (FEA)
45 mm
Max Von Mises
307 MPa
Yield Strength
414 MPa
Safety Factor
1.3
% of max allowable Displacement
14.2 %

21. Questions