1. The Cialitron by LevTech

2. OPERATION 30 minutes continuous use by single operator
Maximum operator payload of 200lbs
Steering column mounted thrust throttle
Operator adjusted lift power
Standing position
Dual rudder steering

3. SAFETY Lift power adjusted prior to mounting
All motors started and checked prior to mounting
Pre-operation inspection of steering and skirt integrity
Protective gear to be worn
Fan-blade housing
Initial trials conducted with supervision and balance assistance

4. LIFT FAN ANALYSIS
Air flow vs. rpm curves for various fan manufacturers require a 12 inch fan, 6 and 8 blades, and fixed pitch of degrees
A fan of this size needs to rotate at approximately 3600 rpm

5. LIFT ENGINE
Air pressure and lift calculations with a fan efficiency of 70% and a motor efficiency of 85% require a 2.5HP motor
The lawn mower engine is oversized by approximately 0.3HP to compensate for pressure losses in the skirt, fan, and platform assembly

6. THRUST ANALYSIS FORCES ON HOVERCRAFT
Reynold’s #:
Air Drag:
Exposed surface, plate approximation: 1.1mX1.6m
μk assumed to be ~ 0.04

7. THE GOVERNING EQUATION
Newton’s 2nd Law:
After solving differential eq. and taking t to gives max velocity
Select a fan that satisfies the constraints

8. SELECTION OF FAN AND MOTOR
30’ diam. 2 blades, 6 hp, 1725 max rpm, 9500 max cfm, 13 degree pitch
Eq. yields 6 max mph
The important properties that affect hover speed: weight, kinetic friction, and fan volumetric flow rate and diameter

9. SELECTION OF THRUST ENGINE
Gas engine with at least 4.5 hp
Engine inefficiency: need hp
6.4 hp, ¾’’ diameter shaft, 4 stroke, electric start, on/off start, choke, and throttle
16.9 L x 13 W x 13.8 H, 55 lbs

10. PLATFORM DIMENSIONS
Dimensions for the plywood platform are 2.5’ x 6.25’
6” extended outrigger system maintains the necessary space for all equipment and the rider
Balance was a contributing factor in the sizing of the platform

11. BOARD DIMENSIONS

12. STRESS ANALYSIS Max Moment = PL/4 Max Stress MY/I = 535 PSI
Yield Stress of
wood = 4,350 PSI
Safety Factor ~ 8

13. TOTAL WEIGHT

14. CONTROLS Rudders swing side to side by moving handlebars
Rudders attached with door hinges and supported by rod
Throttle cables for lift and thrust engine attached to handlebars

15. SKIRT DESIGN Pliable and Durable
Material: Reinforced nylon from a whitewater raft
Attached to outrigger and base to form semi-circle ring
Reinforced holes

16. BUDGET
*We currently have a useable engine for lift, but, since it cannot be left on the Cialitron after the final demonstration, we are looking for a permanent engine

17. WAIVER AND RELEASE
Since our project has a notable risk of injury to the person and property of the rider, we thought it best to draft a waiver releasing Columbia University from liability for any/all injury sustained while riding the Cialitron.
All members of LevTech have signed this waiver.
Any person wishing to ride the Cialitron must sign a waiver.

18. Where do we go from here? Next Steps:
starting fabrication of the parts for which we currently have materials (including the lift engine)
ordering parts from McMaster et al.
continuing our aggressive search for engines that fit within our budget
increasing the intensity of our donation campaign

19. REFERENCES
Baker, Russell, et al. “Solar Splash 2002 Columbia University Technical Report Boat #13.” Columbia University, 1 May 2002.
Beaty, William J. “Ultra Simple Hovercraft.” Science Hobbyist < 27 Jan 2005.
“A Comparison of Different Hovercraft Lift, Thrust and Transmission Systems.” Airlift Hovercraft.< 29 Jan 2005.
“Episode 17: Elevator of Death, Levitation Machine.” Mythbusters. 6 Oct The Discovery Channel, 29 Jan 2005.
“Hovercraft Theory.” Ben’s Hovercraft. 24 Sept 2003 < 27 Jan 2005.
Kurtus, Ron. “Determining the Coefficient of Friction”. School for Champions. 15 Dec Feb <
McMaster-Carr Supply Company Feb <
P. Ponk Aviation. “Propeller Tip Speed Calculator.” Hoverhawk. 10 Feb <
Vawter, Richard. “Drag Force in a Medium.” Western Washington University. Dec Feb <
White, Frank M. Fluid Mechanics. Fifth Edition. New York: McGraw-Hill, 2002.