fairfolio
Saved Projects

Can a Modified Lockwood-Hiller Valveless Pulsejet Engine Be Built that Maintains Self-sustained Periodic Combustion?

CSEF · 2012 Applied Mechanics & Structures

Ian J. Bennett · Sacred Heart Preparatory, Atherton, San Mateo County

Overview

Objectives/Goals In the late 1950#s Ray Lockwood of Hiller Aircraft began his organized study of valveless pulsejet engines and developed the unique U-bend configuration. This study seeks to build a modified Lockwood-Hiller valveless pulsejet engine that maintains a self-sustained periodic combustion process, and test its performance against Tharratt#s 1965 theoretical thrust calculation. The modified Lockwood-Hiller valveless pulsejet engine#s experimental performance data, measured in pounds of thrust, will be less than the prototype#s theoretical thrust calculation, using C. E. Tharratt#s mid-1960#s mathematical analysis. The hypothesis is based on the literature that indicates with many valveless pulsejet engines the margin of error is small, and altering the dimensions incrementally can result in a significant increase or decrease in thrust. Methods/Materials A valveless pulsejet engine is a long hollow tube, open at its ends, with no moving parts. A mix of flat stainless steel and preformed mild steel conical and cylindrical shapes were TIG welded to make the body. Lockwood#s U-bend section is in the middle of the design. Frequent volume recalculations were made to rescale the pulsejet sections. An ignition system was assembled to start the engine and a propane fuel system started and maintained the pulse. Wheels were attached to the body and a simple performance measurement system using a fish-scale device was used to quantify the thrust generated. Results Tharratt#s mathematical model predicted 19.5 pounds of thrust (86.7 N) while 36 pounds of thrust (160.1 N) were measured. Conclusions/Discussion The data did not support the hypothesis and the modified Lockwood-Hiller valveless pulsejet engine#s experimental performance data, measured in pounds of thrust, was greater than the prototype#s theoretical thrust calculation, using C. E. Tharratt#s mathematical analysis. The results show a modified Lockwood-Hiller valveless pulsejet engine that maintains self-sustained periodic combustion can be built, and exceed the maximum pounds of thrust predicted by Tharratt#s theoretical calculation.

Summary statement

This study seeks to build a modified Lockwood-Hiller valveless pulsejet engine that maintains a self-sustained periodic combustion process, and test its performance against Tharratt#s 1965 theoretical thrust calculation.

Help received

Mr. Dino Fry at Dino Fry Racing Enterprises in Redwood City, CA for answered questions during the project, provided access to a machine shop, welding instruction, and fabrication assistance.

Competition history

  • CSEF 2012 Applied Mechanics & Structures · Entry S0306

Resources

Related projects

Closest projects by meaning, across every fair and year in the corpus.

Browse more like this

Source: California Science & Engineering Fair public projects

Save projects to your library

Sign in with Google to keep track of projects you find interesting, organized into folders. An account also raises your daily allowance for “Has this been done?”, and lets you create a key for the MCP server with a much higher limit than anonymous use. Browsing stays public.

Continue with Google