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

Engine Mount Fan Calculations Lift Engine Engine Mount Fan Calculations Briggs & Stratton Vertical Engine Same as last year-Works well 6.5 HP @ 3600 RPM Vertical shaft Weight: 24.3 lbs (w/o fuel and oil) Ready start system 1.0 quart fuel tank w/ Fuel Pump Muffler included

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

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

Engine Mount Fan Calculations Lift Engine Engine Mount Fan Calculations Hovercraft parameters: Length: 160.3 in Width: 68.3 in Footprint area: 9544 in2 Weight: 500 lb 𝑃 𝑐 𝑐𝑢𝑠ℎ𝑖𝑜𝑛 𝑝𝑟𝑒𝑠𝑠𝑢𝑟𝑒 = 𝑊𝑒𝑖𝑔ℎ𝑡 𝐴𝑟𝑒𝑎 =0.052 𝑝𝑠𝑖 𝑉 𝑒𝑥𝑖𝑡 = 𝛽 𝑑𝑖𝑠𝑐ℎ𝑎𝑟𝑔𝑒 2 𝑃 𝑐 𝜌 =0.53 2∗7.488 2.38𝑥 10 −3 =42.07 𝑓𝑡 𝑠 𝐴 ℎ𝑜𝑣𝑒𝑟𝑔𝑎𝑝 = 𝐻 𝑔𝑎𝑝 ∗𝑃𝑒𝑟𝑖𝑚𝑒𝑡𝑒𝑟=0.5∗405.7=202.9 𝑖 𝑛 2 𝑃 𝑏𝑎𝑔 𝑏𝑎𝑔 𝑝𝑟𝑒𝑠𝑠𝑢𝑟𝑒 =1.2∗ 𝑃 𝑐 =0.0624 𝑝𝑠𝑖 𝐿𝑖𝑓𝑡= 𝑃 𝑏𝑎𝑔 ∗𝐴=595.54 𝑙𝑏

Engine Mount Fan/Prop Calculations Thrust Engine Engine Mount Fan/Prop Calculations Kholer PAE-CH740-3003 Improved over last year’s design Lighter Weight More Horsepower Electronic Fuel Injection Brand Kholer Type CH740-3003 CH740-3002 (old) CH740-3002 (new) Power [hp] 27 25 Compression Ratio 9.1:1 9.0:1 Weight [lb] 108 115 94 Displacement [cc] 725 Power-to-Weight [hp/lb] 0.2500 0.2347 0.2660

Engine Mount Fan/Prop Calculations 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

Engine Mount Fan/Prop Calculations 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.

Engine Mount Fan/Prop Calculations 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 𝑟 = 330 2 =1575.63 𝑅𝑃𝑀 Gear Reduction: 𝐺𝑅= 𝐹𝑎𝑛 𝐻𝑢𝑏 𝐸𝑛𝑔𝑖𝑛𝑒 𝐻𝑢𝑏 = 3600 1575.63 =2.28

Engine Mount Fan/Prop Calculations Thrust Engine Engine Mount Fan/Prop Calculations Diameter (ft) A (ft2) mass flow Ue T Tstatic 3.50 9.621 0.8911 183.21 137.16 163.27 3.66 10.55 0.9780 175.10 142.60 171.26 3.83 11.54 1.0690 167.71 147.95 179.2 4.00 12.56 1.1639 160.94 153.22 187.33 4.16 13.63 1.2630 154.72 158.39 195.41 U0 29.308 U1 39.1 ρ 0.002369 Ps 14575

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

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

Questions?

Structures Team The University of Alabama Amber Deja, Victoria Reasoner, Clay Lemley 10/27/2014

Hull Design Based on Chris Sorgatz’s design Similar to 2013-2014 Hoverteam design 160.3 inches long (Approx. 13.35 ft.) 68.3 inches wide (Approx. 5.7 ft.)

Hull Structure Fiberglass Resin Other Materials Hull Structure Fiberglass Resin Other Polypropylene honeycomb material 1” thickness – 3 sheets 0.5” thickness – 9 sheets Total of 384 ft2 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

Hull Structure Fiberglass Resin Other Materials Hull Structure Fiberglass Resin Other

Hull Structure Fiberglass Resin Other 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

Hull Structure Fiberglass Resin Other 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

Hull Structure Fiberglass Resin Other 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

Hull Structure Fiberglass Resin Other 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

Hull Structure Fiberglass Resin Other 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 20-25 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

Hull Structure Fiberglass Resin Other Materials Hull Structure Fiberglass Resin Other

Hull Structure Fiberglass Resin Other 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

Hull Structure Fiberglass Resin Other 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

Costs Item Cost Plascore $617.00 Fiberglass (500 sq. feet 4 oz. S-Glass) $415.00 Epoxy Resin/Hardener (4.35 gal/1 gal) $453.00 Resin Pumps $12.00 Heavy Duty Adhesive (Three 28 fl. oz. bottles) $25.00 Plywood (Three 4’x8’ sheets) Fiberglass Shears $35.00 Other (gloves, cups, etc) $100.00 Total Estimated Cost $1,682.00

Balance Structural Weaknesses Measure Twice, Cut Once 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 Front Hovercraft Hull 160.3 in 80.15 in Actual CG at 93 in Side View of 2014 Racecraft

Balance Structural Weaknesses Measure Twice, Cut Once 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

Balance Structural Weaknesses Measure Twice, Cut Once Improvements Balance Structural Weaknesses Measure Twice, Cut Once 2014 Racecraft Jigsaw used to cut all pieces of honeycomb Cuts were not necessarily straight Angles were not properly cut 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

Questions?

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

Theory Applications Construction Stator Vanes Theory Applications Construction 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. Region of separation = increased drag x 4 x 2

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

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.

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

Stator Vanes Theory Construction Vacuum Bagging: (www.carbonfiberglass.com) Basic kit - $161.50 1 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 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

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: 10.29 lb

Control Surface - Rudders Previous Design New Design

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

Control Surface - Rudders Previous Design New Design

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

Control Surface - Rudders Previous Design New Design Four Rudders – (width of 0.0625 inches) Material: Aluminum Density: 169 lb/ft3 or 0.098 lb/in3 Rudder shape: Triangle Rudder volume(long): 57.75 in3 Rudder volume(short): 48 in3 Total weight: 20.727 lb

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

Control Surface - Rudders Previous Design New Design Three Rudders – (width of 0.0625 inches) Material: Aluminum Density: 169 lb/ft3 or 0.098 lb/in3 Rudder shape: Triangle Rudder volume(long): 60 in3 Rudder volume(short): 51.95 in3 Total weight: 16.06 lb

Control Surface - Rudders Previous Design New Design Turning angle is mostly based on the push-pull cable actuation length. In order to give ourselves a fighting chance, we will purchase the longest cable possible. Upon installation of the first set of rudders, we will find a turning angle that produces the largest turning force. From there the maximum turning angle can be set.

Discussion Calculations 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

Discussion Calculations Cockpit Discussion Calculations Best option is to shift engine, rudder, and propulsion duct forward Component Weight [lb] Local CG Refernce Distance [in] Moment [in-lb] Lift Engine 30 32 960 Lift Engine Mount 15 480 Lift Duct 37 1184 Driver 170 74 12580 Fuel Tank fully loaded 39 77 3003 Battery 6 46 276 Propulsion Engine 125 111 13875 Propulsion Engine Mount 118 3540 Propulsion Duct 90 129 11610 Upper Pulley 1770 Fan and Hub 10 1290 Rudders 50 142 7100 Plascore Hull 35 86 3010 Fiberglass Hull 172 14753 CG Location: 92 inches Move everything up 4 inches with lift duct :88 inches! Move propulsion engine, mount, duct and rudder up another 7 inches: 84 inches!

Questions?