Mudflap wrote: ↑06 Jul 2020, 23:13
henry wrote: ↑06 Jul 2020, 20:57
I’m puzzled by the new part throttle regulations. I can’t make the numbers add up. Can anyone explain it to me?
The regulation:
5.1.5 Below 10500rpm the fuel mass flow must not exceed Q (kg/h) = 0.009 N(rpm)+ 5.5.
5.1.6 At partial load, the fuel mass flow must not exceed the limit curve defined below:
- Q (kg/h) = 10 when the engine power is below -50kW
- Q (kg/h) = 0.257 x engine power (kW) + 22.85 when the engine power is above -50kW
If I set Q to 100kg/h the maximum part throttle power comes out at 300kW. Given that with 100kg/hr at 10500m they probably make around 500kW that’s a big jump from part throttle to full throttle.
I’m also puzzled that the lower bound is MINUS 50kW
Lockdown must have frazzled my brain.
I haven't looked at this in detail but does engine power refer to PU power or ICE power ?
PU power = ICE + MGUK power so when the MGUK is harvesting at part throttle (hence producing negative power) the PU power is lower than ICE power.
-50 kW could be full MGUK harvest (-120 kw) offset by 70 kw ICE power or any combination really.
The section the regulation is in is,
5.1 Engine specification, this deals exclusively with details of the ICE.
However, I think you’re right. This new snippet of Regulation is referring to PU. So the new max part throttle power from the ICE is 420kW. This still seems low.
At least there is one less step for them to control this since they need only compare the PU torque sensor output to the fuel flow.
Fortune favours the prepared; she has no favourites and takes no sides.
Truth is confirmed by inspection and delay; falsehood by haste and uncertainty : Tacitus