Project Overview. The University of Alabama 10/27/2014

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2 Project Overview The University of Alabama 10/27/2014

3 Project Overview Project History Goals Funding Design Basics Inaugural year Formula S Hovercraft (unlimited engine size) Used donated hull Formula 35 Hovercraft (limited to 35 total hp engine(s)) Student built hull

4 Project Overview Project History Goals Funding Design Basics Construct a structurally sound hull for use by future senior design teams Learn from previous mistakes and improve construction techniques Complete hovercraft by March 14, 2015 to allow for testing by Hoverclub of America; race will take place March 28, 2015 Volunteer time and resources for outreach activities Beat Auburn!

5 Project Overview Project History Goals Funding Design Basics Funding Resources Alabama Space Grant Consortium The University of Alabama Student Government Association Fundraising at local food service establishments

6 Project Overview Project History Goals Funding Design Basics Formula 35 Hovercraft Multi-engine designs 35 HP total allowed 4-stroke, 3600 RPM maximum allowed

7 Regulations Racing regulation provided by HCA Based on regulations presented by World Hovercraft Federation (Section 1.c) Each team is responsible for their own compliance (Section 1.b) Encompass safety, noise, design additions, and design compliance

8 Presentation Outline Propulsion Team Team Lead: Andrew Treadway Members: Kelli Harding and Ryan Miller Structures Team Team Lead: Amber Deja Members: Victoria Reasoner and Clay Lemley Controls/Electronics Team Team Lead: Jacob Wilroy Members: Ashley Allison and Liang Zhu Controls and Electronics Jacob Wilroy Liang Zhu Ashley Allison Propulsion Andrew Treadway Kelli Harding Ryan Miller Structures Amber Deja Victoria Reasoner Clay Lemley

9 Propulsion Team The University of Alabama Andrew Treadway, Kelli Harding, Ryan Miller, Daniel Stucki, Timothy Nash 10/27/2014

10 Lift Engine Briggs & Stratton Vertical Engine Same as last year-works well RPM Vertical shaft Weight: 24.3 lbs (w/o fuel and oil) Pull start system 1.0 quart fuel tank w/ Fuel Pump Muffler included Engine Mount Fan Calculations

11 Lift Engine Engine Mount Fan Calculations Modify previous year s design Works well, minor issues

12 Lift Engine Engine Mount Fan Calculations 24 inch fan diameter 5 blades Pitch angle adjustable to 45 Weight: 7.5 lb

13 Lift Engine Engine Mount Fan Calculations Hovercraft parameters: Length: in Width: 68.3 in Footprint area: 9544 in 2 Weight: 500 lb P c cushion pressure V exit = β discharge 2P c ρ = Weight Area = psi ft = x10 3 = s A hovergap = H gap Perimeter = = in 2 P bag bag pressure = 1.2 P c = psi Lift = P bag A = lb

14 Thrust Engine Engine Mount Fan/Prop Calculations Kohler ECH Improved over last year s design Lighter Weight More Horsepower Electronic Fuel Injection Brand Kohler Kohler Kohler Type ECH 749 CH (old) CH (new) Power [hp] Compression Ratio 9.1:1 9.0:1 9.0:1 Weight [lb] Displacement [cc] Power-to-Weight [hp/lb]

15 Thrust Engine Engine Mount Fan/Prop Calculations Modify last year s mount design Reduce vibration May do preliminary design to dampen vibrations on current craft

16 Thrust Engine Engine Mount Fan/Prop Calculations Decided on fan Adjustable pitch and blades Easily replaceable blades (also cheaper) Same dimensions as old craft (propulsive screws are interchangeable) Re-order wooden prop for 2014 craft Ensure correct parameters Vs.

17 Thrust Engine Engine Mount Fan/Prop Calculations Regulations Max Engine Speed: 3600 RPM Max Tip Speed: 330 ft/s Max Fan Speed (4 ft diameter) MFS = V tip = 330 ft = 165 r 2 s Gear Reduction: GR = = RPM Fan Hub Engine Hub = = 2.28

18 Thrust (lbs) Thrust Engine Engine Mount Fan/Prop Calculations Diameter (ft) A (ft 2 ) mass flow U e T T static 250 Thrust vs. Diameter Static Thrust mph U U ρ Ps Diameter (ft)

19 Ducts Lift Same design as last year 24 inch duct Weight: ~5lb Thrust 48 inch duct Weight: ~10 lb Will be strengthened with fiberglass and sheet metal for protection Both ducts will be built with better techniques to ensure constant diameter

20 Skirt Skirt material left over from last year Will use same design, slightly modify dimensions Last year forced to add holes Will build a better balanced craft to alleviate issues

21 Structures Team The University of Alabama Amber Deja, Victoria Reasoner, Clay Lemley Trent Isaak, Jacob Briscoe 10/27/2014

22 Hull Design Based on Chris Sorgatz s design Similar to Hoverteam design inches long (Approx ft.) 68.3 inches wide (Approx. 5.7 ft.)

23 Materials Hull Structure Fiberglass Resin Other Polypropylene honeycomb material 1 thickness 3 sheets 0.5 thickness 9 sheets Total of 384 ft 2 will be ordered Light (total of 35 lbs. to construct hovercraft) Aids in flotation Cost effective $55 per 1 sheet $35.75 per 0.5 sheet Ease of use Cuts smoothly

24 Materials Hull Structure Fiberglass Resin Other

25 Materials Hull Structure Fiberglass Resin Other Inquired about other types of honeycomb Polycarbonate Aramid fiber Contact at Plascore stated polypropylene is the type of honeycomb most widely used for laying up with fiberglass

26 Materials Hull Structure Fiberglass Resin Other Both carbon fiber and fiberglass were considered Carbon fiber costs 4-6 times as much Want to keep the craft light but strong Previous team used 4 oz. E-Glass woven cloth This year, 4 oz. S-Glass woven cloth will be used

27 Materials Hull Structure Fiberglass Resin Other S-Glass is used when extra strength is needed and extra weight is not desired 40% higher tensile strength 20% higher modulus Greater abrasion resistance Same working qualities as standard E-Glass Considered using a heavier E-Glass cloth instead More resin required Increased weight of craft

28 Materials Hull Structure Fiberglass Resin Other Four brands of epoxy resin were compared West Systems 105 was chosen Most widely used, reliable brand Competitively priced with other resins of the same quality 4.35 gallon pail will be ordered

29 Materials Hull Structure Fiberglass Resin Other West Systems 205 Fast Hardener 9-12 minute working time 6-8 hour drying time West Systems 206 Slow Hardener minute working time 9-12 hour drying time Slow hardener will be used Both have same cost Increased working time is a plus Increased drying time will not be an issue

30 Materials Hull Structure Fiberglass Resin Other

31 Materials Hull Structure Fiberglass Resin Other Fiberglass Shears Plywood Create molds to piece together plenum chamber Heavy Duty Adhesive Piece together plenum chamber before fiberglass is applied Paintbrushes

32 Materials Hull Structure Fiberglass Resin Other Epoxy Pumps Ensures correct ratio of resin to hardener Disposable Gloves Disposable Cups For mixing resin and hardener Sandpaper

33 Costs Item Cost Plascore $ Fiberglass (500 sq. feet 4 oz. S-Glass) $ Epoxy Resin/Hardener (4.35 gal/1 gal) $ Resin Pumps $12.00 Heavy Duty Adhesive (Three 28 fl. oz. bottles) $25.00 Plywood (Three 4 x8 sheets) $25.00 Fiberglass Shears $35.00 Other (gloves, cups, etc) $ Total Estimated Cost $1,682.00

34 Improvements Balance Structural Weaknesses Measure Twice, Cut Once 2014 racecraft is very back heavy CG is not at optimum location Driver had to lean forward to attempt to balance the craft while racing Lift duct was moved further toward back of craft than was originally designed Contributed to CG being too far aft 2015 racecraft lift duct will be moved back to original designed location Side View of 2014 Racecraft in Hovercraft Hull in Actual CG at 93 in Front

35 Improvements Balance Structural Weaknesses Measure Twice, Cut Once Addition of fiberglassed honeycomb lip to add more support for the deck Fiberglass both sides of plenum chamber stiffener

36 Improvements Balance Structural Weaknesses Measure Twice, Cut Once 2014 Racecraft Jigsaw used to cut all pieces of honeycomb Cuts were not necessarily straight Angles omitted Pieces didn t fit together properly gap fill used as a remedy 2015 Racecraft Measure TWICE, cut ONCE Tablesaw will be used, especially for larger pieces and to cut angles properly Avoid using gap fill

37 Controls and Electronics Team The University of Alabama Jacob Wilroy, Ashley Allison, Liang Zhu Ethan Slusher, Sara Guiley 10/27/2014

38 Stator Vanes Theory Spinning motion of fan/propeller imparts swirling motion to the air moving through the duct. Fans tend to induce more swirling motion than propellers. Using stator vanes, we can translate the rotational momentum of the air into backwards momentum (thrust) Stator vanes also serve a structural purpose, adding rigidity to the duct, especially near he rudders. Trying to achieve better aerodynamics within the duct. Construction Region of separation = increased drag x 4 x 2

39 Stator Vanes Theory Construction Blade twist leads to change in velocity vector direction Linear blade twist = linear cut along curved portion of stator

40 Stator Vanes Theory Construction Stators can be created using a mold and vacuum bagging technique. Mold can be created from sheet metal bent at the appropriate angle and given the correct curvature. Multiple stator vanes can be created from a single mold. Vanes will be attached to the duct by fiberglass Center piece will be created from Styrofoam covered with fiberglass. All vanes will attach here.

41 Stator Vanes Theory Construction Make stator from plastic fan blade Twist blade to get the correct pitch Smooth leading edge of fan blade will be better than sharp edge of fiberglass plate. Use fan blade = use hub in the center Make stator blades optional/removable

42 Stator Vanes Theory Vacuum Bagging: ( Basic kit - $ VentVac Plus Venturi Vacuum Generator 2 Yds of Peel Ply 1 Yd of Bleeder Breather Cloth 1 Yd of Vacuum Bag 1 Roll of Sealant Tape (25ft.) 2 Yds of Vacuum Tubing Construction Vacuum Bagging Benefits: Needed for molding of parts Can acquire the shape you need Can be used year after year Helps to remove trapped air and distribute resin/hardener

43 Control Surface - Rudders Previous Design New Design Last year s design 5 rudders of the same dimensions Utilize 70 % of flow area Evenly spaced across diameter Rudder size: 24 in x 7 in Rudder shape: triangle Rudder weight: lb

44 Control Surface - Rudders Previous Design New Design

45 Control Surface - Rudders Previous Design New Design Rudder shape Rudders bend and deform easily Consider a stiffer shape or material

46 Control Surface - Rudders Previous Design New Design

47 Control Surface - Rudders Previous Design New Design Option 1 Design Four control surfaces Evenly spaced across diameter Utilize entire duct flow area Two panels: 47 in x 10 in Two panels: 38.4 in x 10 in Constraint: 48 in diameter duct Top View Front View Side View

48 Control Surface - Rudders Previous Design New Design Four Rudders (width of inches) Material: Aluminum Density: 169 lb/ft 3 or lb/in 3 Rudder shape: Triangle Rudder volume(long): in 3 Rudder volume(short): 48 in 3 Total weight: lb

49 Control Surface - Rudders Previous Design New Design Option 2 Design Three control surfaces Evenly spaced across diameter Utilize entire duct flow area One panel: 48 in x 10 in Two panels: 41.5 in x 10 in Constraint: 48 in diameter duct Top View Front View Side View

50 Control Surface - Rudders Previous Design New Design Three Rudders (width of inches) Material: Aluminum Density: 169 lb/ft 3 or lb/in 3 Rudder shape: Triangle Rudder volume(long): 60 in 3 Rudder volume(short): in 3 Total weight: lb

51 Thrust (lbs) Control Surface - Rudders Previous Design New Design Thrust Force vs. Deflection Angle Four rudder design offers slightly better performance in terms of force generated Four rudder design meets the HCA safety regulation regarding openings at the rear of the duct R Total 4R Total Old Total 20 New design provides much better performance over current design Deflection Angle (deg)

52 Cockpit Discussion Calculations Reduce quantity of fuel Move fuel to a different location Creates more problems Shift cockpit forward Shift rear components (P-duct, P-engine, rudders) forward to achieve correct CG

53 Cockpit Discussion Calculations Component Weight [lb] Local CG Refernce Distance [in] Moment [in-lb] Lift Engine Lift Engine Mount Lift Duct Driver Fuel Tank fully loaded Battery Propulsion Engine Propulsion Engine Mount Propulsion Duct Upper Pulley Fan and Hub Rudders Plascore Hull Fiberglass Hull CG Location: 92 inches Best option is to shift engine, rudder, and propulsion duct forward Move everything up 4 inches with lift duct: 88 inches! Move propulsion engine, mount, duct and rudder up another 7 inches: 84 inches!

54 Questions?