General Aviation > Aviation in General

Water injected take offs in the days of the Boeing 707.


Ever wondered what all the smoke was all about?

The smoke you see is the 1700 pounds of water injection used for the Boeing 707s JT engines in those early days.
In fact it is just unburnt fuel/water mix. Injected water cooled the temps enabling more thrust to be generated  for take off.

In fact the J57 that powered the B 52 had similar water injected assistance.

Imagine the opposition today if modern airliner's engines caused such pollution.
That was the price we paid then to get into the jet age and it was acceptable.
For the military, anything to get superiority is acceptable.

How about the 747, did they ever try it? Because I have this picture in my head of a 747 with real bad smoke, but can't seem to find it, maybe my mind is playing tricks on me.

At the time of the development of the 747 all models were equipped with the Pratt & Whitney JT9D-Triebwerk - first of a new generation of turbofan engines, which was hardly sufficient however despite water injection for increase in output from the start.
 Later also the CF6-50 of General Electric and the RB 211 of Rolls Royce were available, whereby the CF6 proved as the most popular engine. For the 747-400 meanwhile 3 different engines are available: general electric CF6-80C2; Pratt and Whitney PW4000; Rolls Royce RB 211.
Although the lack of power is said to be the reason for doing away with the J type engines, I'd bet that new pollution laws had something to do with it too.


[0] Message Index

Go to full version