Thrust Propulsion
Introduction
There are many different methods of vehicle propulsion; some examples of this would be
drive wheels, sails, paddlewheels, and propellers. Thrust propulsion is a result of propellers or
turbines spinning through either the air or water. The basics of thrust propulsion like spinning
objects creating a force through air or water have remained largely unchanged over time, but the
details about casing and controlling them have been improved in various ways. This paper is an
examination of some of the current uses and the current technology of thrust propulsion.
Uses of Thrust Propulsion
One of the main areas of thrust propulsion is boat propellers. Almost all current motor
driven boats use a propeller system for propulsion. The propeller uses the spinning action and
design of the blades to create a thrust to move the boat [1]. There are several different types of
propeller shapes such as elliptical, tapered, props with a lip on the trailing edge, and cleavers that
offer various options in regard to thrust and speed [2].
Another big use of thrust propulsion is aircraft propellers and turbines. The turbine and
compressor spin causing air to be pushed out the back of the nozzle and creating thrust [3].
Turbines are much more complicated than propellers because of all the various pieces of the
turbine such as the inlet, compressor, shaft, burner, turbine, and nozzle [3] and the various ways
in which these and other pieces can be altered to affect the performance of the turbine [4].
One more type of thrust propulsion is the large propellers used in hovercrafts and hover
boats. Hovercraft and hover boat propellers are just giant propellers on the back end of the
vehicle with very little specialty parts to them [5].
Technology of Thrust Propulsion
There are many types of technology that create thrust propulsion to move vehicles. Two
of the main types are propellers and turbines. Propellers are a simpler form of propulsion but can
be made more complex in order to solve various problems and improve performance such as a
shaft assembly to protect the propellers from objects obstructing their spinning [6]. Multiple
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propellers can also be used together to gain efficiency [7] or power [8]. A way to combine
propellers in this fashion is called contra-rotating propellers; the propellers are connected in
series and spin in opposing directions [7].
One more type of propulsion is jet engine turbines. Jet engine turbines use the
compressor and turbine to convert the influx of air through the inlet into thrust coming out the
nozzle [3]. Turbines are more complex than propellers but are also more powerful and create
more thrust.
NASA is working on creating new types of propulsion to be used in space. The first of
these types of propulsion is called Aerocapture and is the process of using a planet’s atmosphere
to slow the craft and slip the craft into orbit. The second type of propulsion is Next Generation
Electric Propulsion, and this technology is an improvement of previous technology such as ion
engines and fission propulsion drives. The third type of propulsion is solar sails, which are very
similar to wind sails, and these sails rely on photons to propel the spacecraft [9].
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[1]
The Marine Doctor Propellers Information Sheet. [Online]. Available:
http://www.themarinedoctor.com/Propellers.htm
[2]
Ace Propeller. Composite. [Online]. Available:
http://www.acepropeller.com/composite.asp
[3]
NASA. (2008, Jul.). Gas Turbine Parts. [Online]. Available:
http://www.grc.nasa.gov/WWW/K-12/airplane/turbparts.html
[4]
H. W. Kim. (2008, Oct.). The Performance Evaluation With Diffuser Geometry
Variations of the Centrifugal Compressor in a Marine Engine (70 MW) Turbocharger. J.
Eng. Gas Turbines Power. [Online]. 131(1). Available:
http://scitation.aip.org.www.library.gatech.edu:2048/journals/doc/JETPEZft/vol_131/iss_1/012201_1.html
[5]
MT-Propeller. Hovercraft Propeller. [Online]. Available:
http://www.mt-propeller.com/en/entw/hover.htm
[6]
H. Ogino, “Propeller shaft assembly for marine propulsion system,” U.S. Patent 5 558
498, September 24, 1996.
[7]
M. Nakayama, “Contra-rotating bearing device for contra-rotating propeller,” U.S. Patent
6 056 509, May 2, 2000.
[8]
H. Jukola and T. Ronkainen, “Contra-Rotating Propellers – Combination of DP
Capability, Fuel Economy and Environment,” in Dynamic Positioning Conf., Houston.
2006, pp. 1-9.
[9]
Imaginova Corp. (2002, May). Space.com [Online]. Available:
http://www.space.com/businesstechnology/technology/advanced_propulsion_0205221.html
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