Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
Does Engine Exhaust Glow At Night?  
User currently offlineCURLYHEADBOY From Italy, joined Feb 2005, 940 posts, RR: 2
Posted (7 years 8 months 6 days 20 hours ago) and read 4748 times:

I was on a night flight on an A320 last July, we were at around FL350 between Greece and northern Africa, it was a moonless night. I had a window seat in a position that allowed me to have a sight of the port engine outlet and I was staring at a beautiful Milky Way sight, when I noticed a dim glowing band, apparently coming from the engine rear and fading, it was sort of a dim azure, I looked carefully and I'm almost sure it was the exhaust gases glowing. Since I'm not 100% sure, i'm asking if someone of you guys can confirm that what I saw is actually the exhaust flow glowing (BTW, I didn't drink any alchool on that flight, lol!) and, if true, can explain the physics behind this sight... does it glow because the gases are so-damn-hot or there is some other reason? Does it always glow and I noticed only because it was dark enough?
Thanks  Smile


If God had wanted men to fly he would have given them more money...
43 replies: All unread, showing first 25:
 
User currently offlineHAWK21M From India, joined Jan 2001, 31573 posts, RR: 57
Reply 1, posted (7 years 8 months 6 days 20 hours ago) and read 4746 times:

If its very Dark outside,One can def notice the Exhaust heat glow depending on Location of View.
regds
MEL



Think of the brighter side!
User currently offlineJHSfan From Denmark, joined Apr 2004, 469 posts, RR: 2
Reply 2, posted (7 years 8 months 6 days 19 hours ago) and read 4714 times:

On this British company page you can find two infrared pictures of airliners - both with the engines running. Hot only does it reveal the heat from the engines, but the landing gear appears also to be very hot.
Although the pictures displays infrared radiation, invisible to our eyes, it tells where to look for a glow if the plane is being watched in darkness. My guess is that we should only be able to see the engine glow. If you can see the landing gear glowing it may be too hot.  hot 

Yours in realtime
JHSfan



Look at me, I´m riding high, I´m the airbornmaster of the sky...
User currently offlineCURLYHEADBOY From Italy, joined Feb 2005, 940 posts, RR: 2
Reply 3, posted (7 years 8 months 6 days 19 hours ago) and read 4710 times:

Thanks JHSfan, those pictures are amazing, looks like the bypass air is hot as well, cool.


If God had wanted men to fly he would have given them more money...
User currently offlineVC10 From United Kingdom, joined Nov 2001, 1397 posts, RR: 16
Reply 4, posted (7 years 8 months 6 days 17 hours ago) and read 4665 times:

Now if you want to see exhausts glowing take a ride on an old piston powered airliner  old 


Big version: Width: 252 Height: 189 File size: 25kb


User currently offlineTimz From United States of America, joined Sep 1999, 6708 posts, RR: 7
Reply 5, posted (7 years 8 months 6 days 17 hours ago) and read 4660 times:

You remember how that Hardy book mentions exhaust flames trailing back over the top of the wing-- I guess it was only Turbocompounds that had an exhaust near the top of the nacelle?

User currently offlineVC10 From United Kingdom, joined Nov 2001, 1397 posts, RR: 16
Reply 6, posted (7 years 8 months 6 days 17 hours ago) and read 4658 times:

The picture is for a 3350 non compound and yes due to the different exhaust layout on the compound the flaming exhaust would stream over the top of the wing.

Now adays passengers would sue if they saw flames but I think in those days they thought it was all part of the thrill of flying

littlevc10


User currently offlineJohnClipper From Hong Kong, joined Aug 2005, 826 posts, RR: 0
Reply 7, posted (7 years 8 months 6 days 17 hours ago) and read 4654 times:

I've seen the same glow on Mesaba Avro/BAe 146s. It's a cool effect.

User currently offlineN231YE From , joined Dec 1969, posts, RR:
Reply 8, posted (7 years 8 months 6 days 16 hours ago) and read 4632 times:

Quoting Timz (Reply 5):
You remember how that Hardy book mentions exhaust flames trailing back over the top of the wing-- I guess it was only Turbocompounds that had an exhaust near the top of the nacelle?

What exactly caused the flames in old piston engines? I'm guessing the fuel mixture was still combusting as the piston was forcing it out of the cylinder in the exhaust stage...but that is, my guess.


User currently offlineStarlionblue From Greenland, joined Feb 2004, 16908 posts, RR: 67
Reply 9, posted (7 years 8 months 6 days 16 hours ago) and read 4615 times:

Quoting N231YE (Reply 8):

What exactly caused the flames in old piston engines? I'm guessing the fuel mixture was still combusting as the piston was forcing it out of the cylinder in the exhaust stage...but that is, my guess.

Correct  Wink

If you look at rally cars, they often have lots of combustion in the exhaust manifold . More power but wears out the engine a lot.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineA342 From Germany, joined Jul 2005, 4675 posts, RR: 3
Reply 10, posted (7 years 8 months 6 days 14 hours ago) and read 4587 times:

Quoting JHSfan (Reply 2):
but the landing gear appears also to be very hot.

From what I can see, it's only the tyres. Not unusual if you think about it. At those speeds and with the weight on those tyres at takeoff, they will heat up a bit, of course.



Exceptions confirm the rule.
User currently offlineHAWK21M From India, joined Jan 2001, 31573 posts, RR: 57
Reply 11, posted (7 years 8 months 6 days 14 hours ago) and read 4562 times:

Quoting JHSfan (Reply 2):
If you can see the landing gear glowing it may be too hot

You mean Tires Glowing.  Smile
regds
MEL



Think of the brighter side!
User currently offlineN231YE From , joined Dec 1969, posts, RR:
Reply 12, posted (7 years 8 months 6 days 14 hours ago) and read 4558 times:

Quoting Starlionblue (Reply 9):

Man I'm so good... wink  (just kidding)

Anyways, thanks for the clarification


Hey, did anyone forget to mention, if you look inside the cowl flaps of the near engine, is that the exhaust manifold glowing?!?



User currently offlineA342 From Germany, joined Jul 2005, 4675 posts, RR: 3
Reply 13, posted (7 years 8 months 6 days 13 hours ago) and read 4539 times:

Quoting N231YE (Reply 12):
Hey, did anyone forget to mention, if you look inside the cowl flaps of the near engine, is that the exhaust manifold glowing?!?

Probably you're right again !

It seems those engines don't have any mufflers !



Exceptions confirm the rule.
User currently offlineStarlionblue From Greenland, joined Feb 2004, 16908 posts, RR: 67
Reply 14, posted (7 years 8 months 6 days 12 hours ago) and read 4513 times:

As I recall, there is a reason why having some combustion in the exhaust manifold of a piston engine increases power. Some device is used in rally cars to achieve the effect.


"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineVC10 From United Kingdom, joined Nov 2001, 1397 posts, RR: 16
Reply 15, posted (7 years 8 months 6 days 11 hours ago) and read 4488 times:

Quoting N231YE (Reply 12):
Hey, did anyone forget to mention, if you look inside the cowl flaps of the near engine, is that the exhaust manifold glowing?!?

The glow inside the cowl flaps is indeed the ring exhaust glowing, and there was definately no mufflers in the system as they would reduce the engines power

The exhaust on the picture shown were jet exhaust so as to recover some power from the exhaust , but how much is a doubtful matter, but in those days every bit helped.

The engines with Power Recovery Turbines [PRT] fitted used the power in the exhaust to drive a turbine which helped drive the engines crankshaft.
At Take-off power the 3 turbines per engines would recover between them about 600HP and add this too the crankshaft. However the PRT were remembered more for their tendancy to blow an oil seal and suck the engines oil system empty and blow it out through the exhaust.

littlevc10


User currently offlineMissedApproach From Canada, joined Oct 2004, 713 posts, RR: 2
Reply 16, posted (7 years 8 months 6 days 10 hours ago) and read 4466 times:

Quoting Starlionblue (Reply 14):
As I recall, there is a reason why having some combustion in the exhaust manifold of a piston engine increases power. Some device is used in rally cars to achieve the effect.

The fuel detonated in rally car exhaust systems is meant to keep the turbocharger spooling when the throttle is closed, in order to reduce turbo lag. The only other thing I can say about the exhaust manifold is that exhaust stream velocity is probably more important than reducing back-pressure. Back-pressure is never desirable, but good exhaust stream velocity produces a scavenging effect in the combustion chamber- when the exhaust & intake valves are open (valve overlap), the velocity of gases leaving the exhaust helps pull burnt fuel out of the combustion chamber & increases engine efficiency.



Can you hear me now?
User currently offlineStarlionblue From Greenland, joined Feb 2004, 16908 posts, RR: 67
Reply 17, posted (7 years 8 months 6 days 9 hours ago) and read 4453 times:

That's the one. Thx MissedApproach!


"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offline411A From United States of America, joined Nov 2001, 1826 posts, RR: 8
Reply 18, posted (7 years 8 months 6 days 7 hours ago) and read 4416 times:

The photo is labeled Connie 749.

If it is indeed a 749 Constellation, then the engines are not CurtisWright turbocompound models.
My only expereince flying the Constellation, was the 1649A model, which absolutely did had the turbocompound series fitted.
The power recovery turbines (3) provided extra BHP directly to the crankshaft, through fluid couplings.
A unique hi-bred design, not without its problems.
The 1649 cruised at at honest 310 knots TAS, consumed 400 gallons of 115/145 avgas per hour, and if it did not run out of oil first, was cabable of 23 hour non-stop flights.
My personal record was 16:30, TPE-HNL.


User currently offlineBri2k1 From United States of America, joined Dec 2004, 988 posts, RR: 4
Reply 19, posted (7 years 8 months 6 days 6 hours ago) and read 4380 times:

Quoting 411A (Reply 18):
The photo is labeled Connie 749.

If it is indeed a 749 Constellation, then the engines are not CurtisWright turbocompound models.

I think the answer's in there somewhere

Quoting VC10 (Reply 6):
The picture is for a 3350 non compound

Fascinating thread. I feel like I should be able to see a glow on lower bypass engines like the JT8D, but I've never seen it.



Position and hold
User currently offlineFLY2HMO From , joined Dec 1969, posts, RR:
Reply 20, posted (7 years 8 months 6 days 3 hours ago) and read 4353 times:

Keep in mind folks, when looking at pictures, some cameras, specially ones with early generation CCD chips, have a tendency to exagerate the glow of hot objects to the point that they make infrared wavelengths visible.

An interesting experiment is to grab an infrared remote controller (a.k.a. your tv's remote) and point it at a digital or video camera. Press any button and you should see the infrared light coming out of the remote through the camera's viewfinder.


User currently offlineVC10 From United Kingdom, joined Nov 2001, 1397 posts, RR: 16
Reply 21, posted (7 years 8 months 5 days 23 hours ago) and read 4312 times:

Quoting 411A (Reply 18):
The photo is labeled Connie 749.

The aircraft to be exact is a C121A which in civil version is the 749A and if you read reply 6 you will see that I say there that they are non compound engines.

In fact the 3350 engine fitted to the Connie 1049 was the first Connie to have PRT engines producing anything above 3150 HP each compared to the 749 non compound engines which produced 2500HP each,

Just for interest the engines in the picture are running either at Meto or climb power but in either case the mixture would be at fully rich setting, which overfuels the engine, the excess fuel being used for cooling and not burnt in the engine. When the mixture is vented through the exhaust valve this hot unburnt fuel comes in contact with fresh oxygen and ignites and thus the flame.

any way be happy littlevc10


User currently offlineOly720man From United Kingdom, joined May 2004, 6604 posts, RR: 11
Reply 22, posted (7 years 8 months 5 days 19 hours ago) and read 4266 times:

It's not the exhaust glowing it's the engine itself. For gas to glow it needs to be rather hotter than an engine will generate.

When I was in Malaysia years ago the B747 engine tailpipes were visibly red on take off... hot, humid, max thrust, high temperatures



wheat and dairy can screw up your brain
User currently offlineCURLYHEADBOY From Italy, joined Feb 2005, 940 posts, RR: 2
Reply 23, posted (7 years 8 months 5 days 18 hours ago) and read 4251 times:

Quoting Oly720man (Reply 22):
It's not the exhaust glowing it's the engine itself. For gas to glow it needs to be rather hotter than an engine will generate.

I'm sure the engines left a dim glowing trail behind them, i could see the tailpipe and it wasn't red. This is the first time I ever noticed such a thing on a flight, that's why I was asking about it... could it be something like gas ionization, something like northern light...?



If God had wanted men to fly he would have given them more money...
User currently offlineBri2k1 From United States of America, joined Dec 2004, 988 posts, RR: 4
Reply 24, posted (7 years 8 months 5 days 16 hours ago) and read 4205 times:

If it was that dark, how can you be sure the ring was gases and not a metal part of the engine? I agree with Oly720man in principle that the engine would have to be red hot for a long time before the gases themselves would start to glow after the nozzle.


Position and hold
25 A342 : The engines also had superchargers. But why wasn't a turbocharger used, instead of those 2 complex systems ?
26 SlamClick : Wish that was a bigger photo. That is so cool! I remember riding on Martin 404s at Southern Airways and seeing not only the exhaust manifold glowing
27 N231YE : I've noticed that too, its kind of interesting.
28 Siren : This might be slightly off topic - however, I read that during the British Airways 009 incident in 1982 that the engines started glowing. I'm not sure
29 VC10 : I am not sure I understand your question[ age you know], but the original 3350 engine was designed with a single stage two speed supercherger, which
30 411A : One civil airplane that I flew used both a supercharger and a turbocharger, and that was the Boeing Stratocruiser. A single speed blower (supercharger
31 2H4 : Silly question, perhaps, but did those engines exhibit characteristics similar to turbo lag in turbocharged cars......that is, delayed power delivery
32 Starlionblue : Interesting question indeed. First of all, there is a difference between a turbocharger and a supercharger. A supercharger needs no time to spool up
33 411A : To answer your question, 2H4, no, turbo 'lag' was not a problem, as the throttles on geared radial engines are moved slowly and carefully, least the r
34 A342 : Well, that's what I don't understand. First, you use PRTs with their complex couplings to recover the energy from the exhaust gases, and put the powe
35 2H4 : Thanks for the input, 411A. But didn't those classic props (Connie, DC-7, etc) commonly require fairly high power settings on final approach to maint
36 Post contains images A342 : Could be true, I don't know. I was born WELL after most examples were phased out !
37 Post contains images Vc10 : A342 Now why Wright chose to fit a supercharger rather than a turbocharger when they designed the original 3350 engine in the late 1930s is unknown to
38 Dufo : I have seen this on both A340 and L-410, sitting in the back..
39 411A : The primary reason turbosuperchargers were not used to better advantage in years gone by was actually quite simple. The types of material used in the
40 JHSfan : You are both right about that. - JHSfan
41 Sovietjet : I have a video of an Il-62 taking off at night where you can clearly see all four engines glowing orange. It's part of a bigger movie but if anybody w
42 Post contains links and images 777WT : Yes they do glow, and if you're lucky, you can see it. Here's one that has been shown here on Anet before but I can't locate the original for credits.
43 ImperialEagle : Thats the truth! I used to love to get the starboard side window next to those big Wrights when flying on the old DC-7's. The way the exhausts were s
Top Of Page
Forum Index

Reply To This Topic Does Engine Exhaust Glow At Night?
Username:
No username? Sign up now!
Password: 


Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Tech/Ops related posts only!
  • Not Tech/Ops related? Use the other forums
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
  • DETAILED RULES
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)


Similar topics:More similar topics...
UPS 757 Landing At Night W/o Lights? posted Thu Nov 16 2006 08:00:51 by Motopolitico
Flight Deck Lighting At Night posted Tue Feb 21 2006 11:06:10 by NWOrientDC10
Engine Exhaust Chevron Concept posted Fri Dec 2 2005 06:30:08 by Speedracer1407
Engine Power Setting At Cruise posted Tue Feb 1 2005 22:54:12 by Gulfstream
Question Re: Engine Exhaust Noise posted Thu Apr 1 2004 23:40:27 by Bsergonomics
777 Engine Exhaust posted Sat Oct 18 2003 02:22:50 by Bruce
Engine Fans Spinning At The Gate posted Sun Sep 28 2003 00:53:38 by FastFlyer
ATC Radio Frequency Changes At Night? posted Wed Jul 16 2003 00:18:15 by Mr Spaceman
DC-3 Engine Exhaust Pipe Question? posted Wed May 14 2003 18:56:19 by Mr Spaceman
DC-10-10 Engine Exhaust Structure posted Tue Jul 16 2002 07:53:37 by Justplanesmart

Sponsor Message:
Printer friendly format