Engine Reverse

mike295855 · January 17th, 2006, 19:19

I have a question. I just want to warn some of you that I do not have the knowledge and/or the correct termanology to present such a quetion so please bare with me.

When an aircraft like the 747,737,777,a320,etc. land there is a set of procedures which is something to the effect of spoilers up, brakes, and reverse thrust.

I have had this idea in my head for quite some time but never thought of asking it. When the aircraft goes in reverse thrust there is usually an opening on the engine which is visible on both sides (obivously this is dependent on the engine type, model, etc), after this occurs immediately after you hear the engines roaring in reverse. How does this work? Does the actual engine stop and begin to go in another direction, or do the fan blades turn around?

SierraPilot123 · January 17th, 2006, 19:25

"When reverse thrusters are deployed vanes partially block the exhaust gases coming out the back of the engine, and some of the exhaust gas becomes diverted (to directions which are mostly up and down) from the back of the engine. Some of the exhaust gases, therefore, obtain a change in momentum, and it is the reverse- thruster vanes which provide the change in momentum. Therefore the vanes obtain momentum toward the back of the jet, since the engine and gases can be considered a closed system and so momentum is conserved, and since the vanes are attached to the engine and the engine is attached to the remainder of the aircraft, the aircraft is braked, or accelerated toward the rear." http://www.madsci.org/posts/archives...9161.Ph.r.html

http://www.aoxj32.dsl.pipex.com/NewF...WReverse2.html

But I do believe there are various types depending in the engine. For example here is a shot of a simpler clamshell type reverse thruster:

I am sure other with more experience can help you out with the details.

mike295855 · January 17th, 2006, 19:28

Thank you very much!

GaTechKid · January 17th, 2006, 19:31

On a pure jet engine the thrust is redirected through sliding doors, clamshell doors, etc. On a turboprop the propeller changes to a negative angle in order to redirect thrust.

Kristie · January 17th, 2006, 20:00

WOW! that's a really good question...I always wondered about that but never thought to ask!

January 17th, 2006, 19:19	#1
mike295855 Junior Member Join Date: Nov 2005 Posts: 76	Engine Reverse I have a question. I just want to warn some of you that I do not have the knowledge and/or the correct termanology to present such a quetion so please bare with me. When an aircraft like the 747,737,777,a320,etc. land there is a set of procedures which is something to the effect of spoilers up, brakes, and reverse thrust. I have had this idea in my head for quite some time but never thought of asking it. When the aircraft goes in reverse thrust there is usually an opening on the engine which is visible on both sides (obivously this is dependent on the engine type, model, etc), after this occurs immediately after you hear the engines roaring in reverse. How does this work? Does the actual engine stop and begin to go in another direction, or do the fan blades turn around?

January 17th, 2006, 19:31	#4
GaTechKid Old Skool Join Date: Aug 2003 Location: Frigid NWA Hub Posts: 1,885	On a pure jet engine the thrust is redirected through sliding doors, clamshell doors, etc. On a turboprop the propeller changes to a negative angle in order to redirect thrust. __________________ "I'd rather screw my way around the country then blow my way around..." - Saab 340 Driver

January 17th, 2006, 20:00	#5
Kristie Big Chief's Woman Join Date: Feb 2001 Location: Scottsdale, Arizona Posts: 18,778 Blog Entries: 3	WOW! that's a really good question...I always wondered about that but never thought to ask! __________________ Wife of a Delta B767 ER F/O jetgirls.net

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January 17th, 2006, 19:25	#2
SierraPilot123 Senior Member Join Date: Aug 2005 Location: Bay Area Posts: 386	"When reverse thrusters are deployed vanes partially block the exhaust gases coming out the back of the engine, and some of the exhaust gas becomes diverted (to directions which are mostly up and down) from the back of the engine. Some of the exhaust gases, therefore, obtain a change in momentum, and it is the reverse- thruster vanes which provide the change in momentum. Therefore the vanes obtain momentum toward the back of the jet, since the engine and gases can be considered a closed system and so momentum is conserved, and since the vanes are attached to the engine and the engine is attached to the remainder of the aircraft, the aircraft is braked, or accelerated toward the rear." http://www.madsci.org/posts/archives...9161.Ph.r.html http://www.aoxj32.dsl.pipex.com/NewF...WReverse2.html But I do believe there are various types depending in the engine. For example here is a shot of a simpler clamshell type reverse thruster: I am sure other with more experience can help you out with the details.

January 17th, 2006, 19:28	#3
mike295855 Junior Member Join Date: Nov 2005 Posts: 76	Thank you very much!