Moderators: richierich, ua900, PanAm_DC10, hOMSaR
Faro wrote:When exactly did the practice of reduced thrust takeoffs originate? Was it in the 1960's with the early turbojet airliners already or later? Those early jet engines were not that powerful to start with...
Faro
CosmicCruiser wrote:yep, we did reduced thrust t/o in the 727. remember all the charts well
Andre3K wrote:You guys are missing the point. He isn't talking about low bypass turbofan's, he is talking about PURE TURBOJET's. The 727 doesn't count, the 737-100/200's don't count, anything with any bypass at all doesn't count.
CosmicCruiser wrote:yep, we did reduced thrust t/o in the 727. remember all the charts well
GalaxyFlyer wrote:Of course, you could use reduced thrust without EECs. We did on the B727 in 1978.
Gf
OldAeroGuy wrote:I think a de-rated JT3C takeoff was with no water injection.
Balerit wrote:All SAA's long haul take -offs from JNB in the early days were done with water injection, from the B707's right up till our JT9-7F's on the B747 SP's, those early P&W's were very under powered.
Max Q wrote:Balerit wrote:All SAA's long haul take -offs from JNB in the early days were done with water injection, from the B707's right up till our JT9-7F's on the B747 SP's, those early P&W's were very under powered.
Pet peeve department
The engines weren’t underpowered,the aircraft was !
Balerit wrote:Max Q wrote:Balerit wrote:All SAA's long haul take -offs from JNB in the early days were done with water injection, from the B707's right up till our JT9-7F's on the B747 SP's, those early P&W's were very under powered.
Pet peeve department
The engines weren’t underpowered,the aircraft was !
I'm not sure what you are getting at but our Super B's with the JT9's were rated at about 41 000 lbs of thrust. The A300 's that we received came with CF 6's, rated at 50 000 lbs.
The B747 was over engineered and over the course of their lives we spent much time on removing unwanted equipment, things like the turbine thrust reversers or the humidifier systems. Also there is so much wasted empty space above the passenger compartment ceiling.
77west wrote:
I think he meant the engine produced its design rated power, only that the aircraft should have had more powerful models. So the airframe was underpowered, not the engine itself.
I can only imagine a 747 with only 41K engines out of JNB on a hot day... that would have been a long takeoff roll. Thats not that much more thrust than the A340-300...
77west wrote:Balerit wrote:Max Q wrote:
Pet peeve department
The engines weren’t underpowered,the aircraft was !
I'm not sure what you are getting at but our Super B's with the JT9's were rated at about 41 000 lbs of thrust. The A300 's that we received came with CF 6's, rated at 50 000 lbs.
The B747 was over engineered and over the course of their lives we spent much time on removing unwanted equipment, things like the turbine thrust reversers or the humidifier systems. Also there is so much wasted empty space above the passenger compartment ceiling.
I think he meant the engine produced its design rated power, only that the aircraft should have had more powerful models. So the airframe was underpowered, not the engine itself.
I can only imagine a 747 with only 41K engines out of JNB on a hot day... that would have been a long takeoff roll. Thats not that much more thrust than the A340-300...
Faro wrote:When exactly did the practice of reduced thrust takeoffs originate? Was it in the 1960's with the early turbojet airliners already or later? Those early jet engines were not that powerful to start with...
Faro
Max Q wrote:Great description and I understand
My point was there’s a tendency to describe an engine as ‘underpowered’
An engine can never be underpowered, it
can have a relatively low thrust for its size
and weight but that’s only an issue if it’s bolted to an airframe that is heavier than
desired for the installed thrust
Then that aircraft is underpowered