Composite Manufacturing Group 15 Eglin AFB Brandon Bair - John Brewer - Darnell Brown - Rob Contes Sponsor: Jeff Wagener - Lt Joe Czabarnek, AFRL Faculty Advisors: Dr. Chiang Shih (ME) - Dr. Richard Liang (IE)

Introduction Scope AFRL Fuselage Specifications Project Specifications Research Selection Original Design Design Development Construction Testing Hiring Conclusions Recommendations Summary Questions

Scope The scope of this project was to redesign and test the fuselage of the Bullwinkle Micro Aerial Vehicle and “hire” a manufacturer to produce it.

AFRL Fuselage Length ” Width ” Height ’’ Construction 2 part Design Male mold Pre-impregnated carbon fiber Assembled with nylon screws Motor Mount – Sheet aluminum

Project Specifications Same size and shape Survive a 30 o impact at 20 m/s (45mph) Ensure that motor heat will not affect structure Manufacturing 30 units $300 per unit $20,000 for start-up 1 month start-up, 1 month production

Research Materials Resin Processing Curing

Research: Materials Glass Fiber Carbon Fiber Kevlar

Glass Fiber Pros Lightweight Inexpensive Cons Heavier than other composites

Carbon Fiber Pros Light weight Very strong Durable Cons Very expensive materialogical.com/wordpress/?cat=7

Developed by DuPont in 1965 Pros Thermal and electric insulator Absorbs energy Cons Breaks down in UV light Sublimes at 450 o C Kevlar

Research: Resin Polyester Inexpensive Low order crosslinking Epoxy Difficult to use High order crosslinking Vinyl Ester Compromise Easy to use

Research: Bonding Processes Resin Transfer Contact Molding Vacuum Bag

Resin Transfer Process Material held in a closed mold Resin injected Pros Smooth, even sides Few voids Cons Complex molds Resin rich

Contact Molding Also known as Hand Lay-Up Molding Material and resin are applied with a roller or brush by hand Pros Inexpensive Fast Cons Resin rich Labor Messy

Vacuum Bag Molding Applies vacuum to hold a part securely to a mold Pros Product is smoother Controlled fiber and resin ratio Cons Time consuming Materials

Possible Curing Processes Autoclave – High temperature and pressure Oven – High temp Room temperature

Selection Material – Carbon Fiber Light weight Strong Standard in military MAV construction Resin – Vinyl Ester Forgiving catalyst ratio Strong and tough Process – Vacuum Infusion Control resin ratio Low voids Molds – Female, Plaster

Original Design Solid nose Main structure with cap Four parts 10 Bonding strips

Design Development 4 main parts to 2 main parts Flat sheet 2 Bonding strips Cap Simpler Faster production More continuous structure and surface

Design Development

Construction: Molds Wooden mold box Acrylic Wax Rapid prototyped male mold form Industrial gypsum plaster Wax

Construction: Fuselage Wax Poly Vinyl Alcohol (PVA) Carbon Fiber Peel Ply Flow Media Vacuum Bag

Bench Test Run 1 Full Power for 5 min No temperature change Run 2 50% for 7 min No temperature change Run 3 25% for 15 min No temperature change

Impact Testing Propelled with a pneumatic cannon Impacted a target ramp at 30 o Speed measurement – Calibration board and semi- high speed camera (120 fps)

Impact Results With motor Minimal damage Motor plate separation Retained structure With weight (3 lb total) Visible damage Motor plate separation Retained structure

Impact

Hiring ACMA Preliminary Contact Quote Request Package Detailed description Detailed drawings Prototype pictures Separate package for motor plate

Conclusion Fuselage Manufacturer –TBD by AFRL At least 6 interested companies Timeline Production Motor Plate Manufacturer – Milco Water Jet Lot Price - $190 ($6.33 per unit) Timeline - 5 days

Recommendations Construct parts in house Low production numbers Quality control Variability Cost Research vacuum molding of polymers Quicker Less expensive Compliant parts

Summary Scope AFRL Fuselage Specifications Project Specifications Research Selection Original Design Design Development Construction Testing Hiring Conclusions Recommendations Summary Questions