What makes a jet engine smokey?

lemontree · 08-31-2006, 00:14 AM

If one observes the difference between US and Russian jet engines, the later are found to emit more black smoke. Maintenance could be one issue but a jet engine is a relatively simple design, so what makes some engines emit black smoke.

sappersgt · 08-31-2006, 00:38 AM

Quote:

Originally Posted by lemontree

What makes a jet engine smokey?

If one observes the difference between US and Russian jet engines, the later are found to emit more black smoke. Maintenance could be one issue but a jet engine is a relatively simple design, so what makes some engines emit black smoke.

The engines in the F-4 Phantom are notorious for the trail of smoke they leave behind. I think it's a design issue.

Archer · 08-31-2006, 01:04 AM

Quote:

Originally Posted by lemontree

What makes a jet engine smokey?

If one observes the difference between US and Russian jet engines, the later are found to emit more black smoke. Maintenance could be one issue but a jet engine is a relatively simple design, so what makes some engines emit black smoke.

Improper combustion. Basically you need to combust/burn all the fuel properly and not leave a trail...in videos, you can see even EF's modern turbofans smoke at certain maneuvers/ altitudes- I guess the flow of air through the engine didnt permit full combustion, besides which the MiG-29s in several airshows have been quite smoky..so its a combination of design and airflow imho.

Jet engines are imho, the most difficult things to design & manufacture, and plotting out the airflow and ensuring that they deliver stable performance at all different angles of attack, airspeeds etc, that the aircraft has to go through is a big PITA.

lemontree · 08-31-2006, 02:11 AM

Quote:

Originally Posted by Archer

Improper combustion. Basically you need to combust/burn all the fuel properly and not leave a trail...in videos, you can see even EF's modern turbofans smoke at certain maneuvers/ altitudes- I guess the flow of air through the engine didnt permit full combustion, besides which the MiG-29s in several airshows have been quite smoky..so its a combination of design and airflow imho.

Does a pulse jet engine solve this problem (at the cost for speed?)?

gunnut · 08-31-2006, 03:30 AM

Quote:

Originally Posted by lemontree

Does a pulse jet engine solve this problem (at the cost for speed?)?

Only if it achieves complete combustion.

Black smoke comes from incomplete combustion. Ever seen old films of B-52s taking off with max payload? Notice the 4 column of black smoke so thick that you can practically walk on them? That's from water injection. Someone figured that pouring water into a hot jet engine can raise thrust. What happens when you pour water into a hot fire? Temperature drops. Lower combustion temperature results in incomplete combustion, thus heavy black smoke from old BUFFs.

Western engines have better metallurgy than Russian engines. Better metallurgy allows higher temperature in the combustion chamber and more complete burn. Of course this is an over simplification. Other factors go into how efficient the engine is. But overall, higher temperature, more efficient engine, will result in less smoke.

HistoricalDavid · 08-31-2006, 04:51 AM

http://www.sky-flash.com/Bombers/014.jpg

lemontree · 08-31-2006, 07:38 AM

Thanks guys

gunnut · 08-31-2006, 13:56 PM

I was thinking about this one:

http://www.fas.org/nuke/guide/usa/bomber/b-52_i.htm

HistoricalDavid · 08-31-2006, 14:17 PM

Now THERE's a rallying point for the environmentalists.

lemontree · 09-01-2006, 00:44 AM

Quote:

Originally Posted by gunnut

I was thinking about this one:

http://www.fas.org/nuke/guide/usa/bomber/b-52_i.htm

They look as if they are on fire.

Tronic · 09-01-2006, 01:07 AM

Quote:

Originally Posted by HistoricalDavid

Now THERE's a rallying point for the environmentalists.

hey... I happen to be one... thank you very much....

08-31-2006, 00:14 AM	#1 (permalink)
lemontree Bandaid *Military Professional* Join Date: 10-04-04 Location: India Posts: 5,928	What makes a jet engine smokey? What makes a jet engine smokey? If one observes the difference between US and Russian jet engines, the later are found to emit more black smoke. Maintenance could be one issue but a jet engine is a relatively simple design, so what makes some engines emit black smoke. __________________ Cheers!...on the rocks!!

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
LCS christened	HKDan	Naval Forces	208	10-26-2006 15:41 PM
The Irony that is the GE F-136 Engine	jgetti	Military Aviation	24	08-31-2006 13:04 PM
DRDO looking for global technical partner to develop Kaveri engine	oneman28	South Asian Defense Topics	66	07-15-2005 06:38 AM
5th generation military jet trainer makes first appearance at paris airshow	Y W F	Military Aviation	1	06-21-2005 20:41 PM
IAF purchasing more and more.	ajaybhutani	South Asian Defense Topics	54	04-20-2005 09:05 AM

08-31-2006, 04:51 AM	#6 (permalink)
HistoricalDavid Distant Deeps or Skies *Senior Contributor* Join Date: 07-19-05 Location: North London, UK Posts: 2,122 Country:	http://www.sky-flash.com/Bombers/014.jpg

08-31-2006, 07:38 AM	#7 (permalink)
lemontree Bandaid *Military Professional* Join Date: 10-04-04 Location: India Posts: 5,928	Thanks guys

08-31-2006, 14:17 PM	#9 (permalink)
HistoricalDavid Distant Deeps or Skies *Senior Contributor* Join Date: 07-19-05 Location: North London, UK Posts: 2,122 Country:	Now THERE's a rallying point for the environmentalists.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)