Re: Aviation nostalgia...

[Jim Baker]

"avfan" > wrote in message
news:j1c2b0h37tm0cvslp7o92q0k47rrsjdf8t@news...
>
> http://www.airliners.net/open.file/541868/M/
>
> Ah those were the days...

I wonder if those commercial aircraft used water injection.

Imagine that aircraft with 8 engines, spewing double the smoke, and another
one just like it 12 seconds behind....and at least one more 12 seconds
behind number 2. Now you've got a B-52G MITO takeoff.

JB

[tom418]

Some 707s DID use water injection.
"Jim Baker" > wrote in message
...
>
> "avfan" > wrote in message
> news:j1c2b0h37tm0cvslp7o92q0k47rrsjdf8t@news...
> >
> > http://www.airliners.net/open.file/541868/M/
> >
> > Ah those were the days...
>
> I wonder if those commercial aircraft used water injection.
>
> Imagine that aircraft with 8 engines, spewing double the smoke, and
another
> one just like it 12 seconds behind....and at least one more 12 seconds
> behind number 2. Now you've got a B-52G MITO takeoff.
>
> JB
>
>

[Bob Moore]

"tom418" wrote
> Some 707s DID use water injection.

Yes, more specifically, the early -100 series with the P&W
JT3C-6 engine producing 13,500# of thrust with water injection.
With the availability of the P&W JT4A-3 engines @ 15,800 # of
thrust without water injection, the airframe was enlarged to
the early -300 series while P&W was busy adding a front fan
stage to the JT3-C to produce the JT3-D series of engines
producing over 18,000# of thrust which would power the improved
-300 series and the later 720 model aircraft.

Bob Moore
17 years in 707s

[Jim Baker]

"Scott M. Kozel" > wrote in message
...
> "Ralph Nesbitt" > wrote:
> >
> > "matt weber" > wrote
> >
> > > Early jet engines often had multiple small combustion chambers, the
> > > volume to surface ratio prevented the temperatures from getting high
> > > enough in parts of the chamber to burn the fuel effectively and some
> > > even had an exhaut pipe for each chamber. As the materials improved,
> > > a switch to a single combustion chamber, with a much more favorable
> > > surface to volume ratio and higher combustion chamber temperatures
> > > produced more complete combustion, and the black exhaust plume started
> > > to disappear. By the early 1970's such plumes had become rare on
> > > commercial jets in the USA.
> >
> > As a boy growing up in the mid 50's we lived near a SAC Base. An "Alert
> > Scramble/Launch" was a sight to see.
> >
> > The above Pic is from a single 707. Consider the smoke put off by a
dozen
> > B-52's followed by a dozen KC-135's using "Powder Charges" to start the
> > engines. It would take ~ 30 minuets for all the B-52's & KC-135's to get
> > airborne.
> >
> > If there was little/no wind the smoke would hang over the base for
hours.
>
> What has been done to make the B-52s less smoky? There was talk about
> 15 years ago of re-engining them with 4 large turbofans to replace the 8
> original Jet engines, but that was not done.

All the turbojet models are retired, the last one being the G model. The H
model has fanjets and thus doesn't use water for added thrust on takeoff.

JB

[Big John]

Matt

I'll use your post to stick my 2 cents in.

Long before my retirement from the USAF, I was told that the smoke
trail out of the US engines was caused by the engine design where an
internal bearing was oiled by a spray and that that oil migrated back
and was burned and made the smoke trail.

Used to see and take my Fighter off behind B-52's and their heavy
smoke all the time at SAC bases.

Also the smoke trail worked against the F-86. It was much easier to
spot the F-86 with their smoke trail then the Russian MIG which didn't
have a smoke trail.

Amy one out there want to take this up and add to this technical
issue?

Seem to remember that the B-52(s) that flew non stop around the world
(used air to air refueling) had extra oil tanks installed so there
would be enough oil for the trip????

Long time ago in a land far away................

Big John
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~`


On Tue, 25 May 2004 22:03:12 -0700, matt weber >
wrote:

>On Tue, 25 May 2004 00:11:32 -0400, "Scott M. Kozel"
> wrote:
>
>>"Ralph Nesbitt" > wrote:
>>>
>>> "matt weber" > wrote
>>>
>>> > Early jet engines often had multiple small combustion chambers, the
>>> > volume to surface ratio prevented the temperatures from getting high
>>> > enough in parts of the chamber to burn the fuel effectively and some
>>> > even had an exhaut pipe for each chamber. As the materials improved,
>>> > a switch to a single combustion chamber, with a much more favorable
>>> > surface to volume ratio and higher combustion chamber temperatures
>>> > produced more complete combustion, and the black exhaust plume started
>>> > to disappear. By the early 1970's such plumes had become rare on
>>> > commercial jets in the USA.
>>>
>>> As a boy growing up in the mid 50's we lived near a SAC Base. An "Alert
>>> Scramble/Launch" was a sight to see.
>>>
>>> The above Pic is from a single 707. Consider the smoke put off by a dozen
>>> B-52's followed by a dozen KC-135's using "Powder Charges" to start the
>>> engines. It would take ~ 30 minuets for all the B-52's & KC-135's to get
>>> airborne.
>>>
>>> If there was little/no wind the smoke would hang over the base for hours.
>>
>>What has been done to make the B-52s less smoky? There was talk about
>>15 years ago of re-engining them with 4 large turbofans to replace the 8
>>original Jet engines, but that was not done.
>
>The current inventory I believe is all H models, and H's have ended up
>with TF33PW-103's engines, which is the miltary version of a late
>model JT4, in otherwords a turbofan without water injection.All prior
>model B52's used the J57, which is a turbojet, not a turbofan, and no
>doubt water injected...
>
>In short, replace the cans with larger burner, get rid of the water
>injection, add a turbofan and a better designed combustion chamber,
>and most of the smoke disappears...
>
>
>The civilian vesion of the J57 is a JT3 (turobjet), used on early
>707's, the civilian version of the TF33 is the JT4, used on later
>707's. J57 is a 12,000-13000 pound thrust engines, most of the TF33's
>are 17,000-18,000 pounds.