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Post by fwx on Feb 8, 2013 12:36:48 GMT 12
A P3 flew over me just a short time ago, over the Northern motorway, lining up for Whenuapai, trailing four bloody great brown trails behind ...
It seemed worse than what I've noticed before, and made me wonder why we don't see such trails from commercial turboprops? Is it just the vintage of the engines, or is the Defence Force trying to get by on diesel, or vegetable oil perhaps??
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Post by jonesy on Feb 8, 2013 13:10:56 GMT 12
Cue the conspiracy theorists..... ;D
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Post by corsair67 on Feb 8, 2013 13:19:57 GMT 12
A P3 flew over me just a short time ago, over the Northern motorway, lining up for Whenuapai, trailing four bloody great brown trails behind ... It seemed worse than what I've noticed before, and made me wonder why we don't see such trails from commercial turboprops? Is it just the vintage of the engines, or is the Defence Force trying to get by on diesel, or vegetable oil perhaps?? Engine overhauls now done by a mobile mechanic using cheap engine oil and spare parts? ;D |
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Post by Dave Homewood on Feb 8, 2013 13:41:21 GMT 12
I reckon if you were lost at sea, those four black trails would be a very welcome sight.
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Post by raymond on Feb 8, 2013 15:10:41 GMT 12
There are others who can explain why its so smokey, remember these engines are way over 40 years old.
There were a few modifications that were around to reduce the amount of smoke, I can remember discussing with the REO mangere these a number of years ago but as to what happened???
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Post by keroburner on Feb 8, 2013 16:11:25 GMT 12
Pretty sure most, if not all Turbo prop and Turbo Jet engines of that age produce a bit of visible exhaust gas. I notice it looks worse when viewed front on or tail on. Compared when viewed flying directly overhead. Even our 737-300's produce a faint black trail some times at takeoff and max cont. power settings. The local Convair fleet are no different either. I personally think it adds to the sight and sound of these planes. Imagine a clean green shuttle or rocket launch.......... Boring!!!!
Go for the burn I say!!
Bring on the War emergency Power/Water meth injection haha
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Post by beagle on Feb 8, 2013 16:48:07 GMT 12
I would say it is coming up for it's compressor wash soon, plus maybe a 30 or 35 day, can't remember which one it is. This is their good scrub and clean and probably a bit of soot on those exhaust shrouds.
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Post by Dave Homewood on Feb 8, 2013 17:29:57 GMT 12
Hilarious Mike! ;D
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Post by ngatimozart on Feb 8, 2013 17:57:24 GMT 12
Chem trails ;D
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rhyno
Flight Lieutenant
Posts: 90
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Post by rhyno on Feb 8, 2013 18:56:55 GMT 12
Dont joke about chem trails...you will have them crawling out from under drain covers !
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Post by suthg on Feb 8, 2013 19:01:08 GMT 12
Yes I hope the Google Search function does not pick up on this thread...
Its typical for P3 and other types to show some trail, it was obvious in the dry clean air over Hood Aerodrome when 03 came through, cleaner watching the more modern jet the 757 though - but hey! That's how they came and that's how they look. Don't change them!!
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Post by Radialicious on Feb 8, 2013 19:08:49 GMT 12
I seem to remember the RAAF was involved in a modification programme on the T-56 engines in their fleet to reduce the exhaust smoke. Mods to the combustion cans altered/improved the airflow through the hot section and I guess, improved the burn characterstics.
As Raymond says, these engines aren't new - in fact the design turns 60 next year!
I worked on both models of the RNZAF T-56 and the civil Allison 501 during my time with SAFE Air. A truly superb engine. I remember the compressor of an industrial T-56 visiting the shop for a dynamic balance. It was much beefier than the aeronautical version and was used in some sort of powerplant capable of 8000hp and designed to run for months on end.
I was also involved in performance testing these engines at the Air NZ engine centre in Auckland. The test bed was at nearing the end of its life but its history was quite fascinating. It was, at the time, purely for testing the T-56 but there was clear evidence of its past. Our control console was at the same level as the big engine when it was bolted to its mountings. We were able to observe the engine through a thick double glazed window. In a room below was a console that was used to start, run and test the Iroquios Lycoming T-53 many years earlier. Inside the 'cave' itself were mountings that used to support the early P & W turbo jets from the DC-8. In the room where we tested the T-56, we sat with our backs to the Bristol Hercules test console which was still complete. It even had a large set of scales that held an oil tank. Somehow, this was used for accurately determining the oil consumption of the engine on test.
The whole facility was nearing the end as it had been earmarked for conversion to another purpose.
We would often base two or three engineers in Auckland for several days testing repaired and overhauled engines. If the squadrons weren't demanding engines in a hurry, we'd have a handful of engines up there at a time and chip away at them until they were all serviceable. Good times.
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Post by ngatimozart on Feb 8, 2013 19:29:30 GMT 12
Dont joke about chem trails...you will have them crawling out from under drain covers ! We are well informed (& misinformed) on them having had a great discussion last year. Just couldn't resist it. ;D |
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Post by Deane B on Feb 8, 2013 20:05:37 GMT 12
I seem to remember the RAAF was involved in a modification programme on the T-56 engines in their fleet to reduce the exhaust smoke. Mods to the combustion cans altered/improved the airflow through the hot section and I guess, improved the burn characterstics. As Al has pointed out, the black smoke is the result of incomplete combustion. The RAAF only had limited success in improving it. C130's also "smoke" as do Convairs with the Allison 501's. It seems to be more noticeable at lower speed, perhaps because there is less dilution with surrounding air. Additionally, when flaps are deployed, the deflection of the smoke trails can make them more visible. |
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Post by raymond on Feb 8, 2013 20:17:26 GMT 12
Had a guy ring the office once. He was outside in his garden and saw an aircraft going overhead (identified it was a herc) and was concerned about all of the smoke coming out and how it was polluting the air. Any way found out he was concerned as he had had a lung removed and had to be careful about fumes etc. This all took about 40 minutes and I referred him on to CO Tech Wing Ak, Airstaff, & CAS who might be more suited to answering his concerns....What was he doing in the garden...mowing the lawns with his 2 stroke mower
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Post by suthg on Feb 8, 2013 20:19:39 GMT 12
There is always a dimwit who complains - perhaps I have had too many wines tonight...
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Post by fwx on Feb 8, 2013 20:51:07 GMT 12
Oi, who's calling me a dimwit??
No seriously, thanks for all the answers to my question, technical and otherwise ... very interesting, and just shows how much knowledge there is on this forum.
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Post by suthg on Feb 8, 2013 21:16:55 GMT 12
But that would still be the issue with the de Havilland Goblin fitted to the Vampire and designed in 1941 by Frank Halford (moving on after he designed the world's petrol fuelled highest powered, inline, production engine - the Napier Sabre H24) as it was a new jet engine inefficient by today's standards - but seemingly a lot cleaner in its exhaust.
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Post by kiwiinoz on Feb 8, 2013 21:58:15 GMT 12
If you want to see smoke trails check out the B52, you couldn't make more if you tried to on purpose
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Sarge
Flight Sergeant
ex Grocer and living Museum exhibit
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Post by Sarge on Feb 8, 2013 22:14:31 GMT 12
It is actually to help the pilot see the area he has covered when doing an area search. Maybe if he has to turn around, he can check the wind drift
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