Hail Damage Test Process Design USAF
Project
Wing dimpling due to hail damage can result in costly aircraft reskin efforts
Objective: Determine the aerodynamic effects of hail damage on a NACA 0012 wing section
- Angle where the aircraft stalls
- The maximum lift of the aircraft
- The drag on the aircraft due to dimpling
T-38 https://www.airforce-technology.com/projects/t-38/
Hail damage picture courtesy of Robert Hone USAF
Process
Simulation Process
- Total Hail Mass (MATLAB)
- Hailstone sized (MATLAB)
- Center Deflection (MATLAB)
- Point Control Volume (C++)
- ScanTo#d solid Model (SolidWorks)
- Create Control Volume (STAR-CCM+)
- Physics and Solver (STAR-CCM+)
Testing Process
- Damage levels: Undamaged, ground, inflight
- Flight conditions: Take-off/landing, cruising
- Five models tested
- Iterate the angle of attack
- Statistical post-processing
Results
Local separation tripped by single dimple near leading edge
Low angle separation and high angle reattachment due to damage pattern
Undamaged gradual separation vs damaged sudden separation
350 KTAS freestream shock separation near leading edge
Conclusion
| Flight Condition | Damage Condition | Angle of Seperation | Max Lift Coeff. | Drag Coeff. at 00 AoA |
| Take-off/landing | Undamaged (baseline) | 17 degrees | 1.632 | 0.00742 |
| Ground | 11.529 degrees (-38%) | 1.188 (-32%) | 0.00784 (+6%) | |
| Inflight | 12.734 degrees (-29%) | 1.365 (-18%) | 0.0074 (+0.34%%) | |
| Cruising | Undamaged (baseline) | 7.562 degrees | 0.865 | 0.00841 |
| Ground | 6.6 degrees (-14%) | 0.771 (-12%) | 0.00877 (+4%) | |
| Inflight | 6.925 degrees | 0.815 (-6%) | 0.00865 (+3%) |
Thank you to our Project Manager Derek Scott, our Faculty Advisor Spencer Wendel, and our Mentor Robert Hone
Allen Crapo Email: allenjames.skiing@gmail.com
Dallin Krebs Email: krebsda@gmail.com
Janelle Miller