RR Trent - IEPR?
 

I remember reading that the Trent engines do not use IEPR, is this correct?

If so, why did RR decide to not use it as they did on the RB211?


Another thing, I was reading about the incident in the Pacific when they had a blocked Pt2 tube (Takeoff B732) - the Captain writing the article talks about what happened when they switched on the anti-ice and got strange indications on the EPR gauge:

My mind went back to a paragraph in the
Potomac accident report which mentioned
that with the engine anti-ice switched on and
the PT2 tube blocked, the EPR needle would
indicate a reverse reading to that expected.

I don't get it - wouldn't the EPR indication be lower, either the Pt2 becomes 'unblocked' -> lower EPR(?). Or, if it remains blocked, you have a normal(?) drop in the EPR because of the increased bleed?

The RR trent does indeed use EPR (Im afraid I dont know what IEPR is.

Its actually probably a better indication of engine thrust than setting N1 is, but is a lot more difficult to set accurately due to its sensitivity (humble opinion based on RR powered 777s).

Asf for the icng questions Im afraid I know nothing.....!!!

VR- are you seriously directly comparing a 737-200 Pratt & Whitney engine with 747 Rolls big fan technology? This EPR/N1 discussion is constantly simmering. We used Pratt & Whitney 747 engines with EPR along with Rolls Royce engines. There is no problem.

I was "seriously directly" asking two (not necessarily related) questions! I don't see your answer being related to either one of those.

SinkRate, IEPR - IntegratedEPR. Different from the EPR in that it also takes the fan stream into the calculation of the pressure ratio.

All those years looking at the EPR gauge, having checked the probe during the walkround, thinking it was all about the "fan stream"

Integrated Engine Pressure ratio. The indication is obtained by taking pressure signals from both the cold stream (PF) and the hot stream (P8) and comparing them with intake pressure (P1). The resultant is converted to an electrical signal and displayed at the flight station as EPR.

HDB, it is due to a blocked probe becoming a air container, heat it up, and the air expands. As it is now locked in the pressure goes up. With high temps, this will totally overshadow any real pressure change from the engine openig bleeds etc.

Correct me if i,m wrong, it's a long time since the course, but doesn't the RR RB211-535E4 on the 757 use integrated EPR? I seem to remember it uses a mix of P0(fan inlet) and P3 (HPC inlet) at the front and P8 at the back end?