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757 Captain >> 757 version 4.x (FSX ONLY) >> Engine Spool-Up/Thrust Modeling
https://www.captainsim.org/forum/csf.pl?num=1231517662

Message started by bearste on Jan 9th, 2009 at 4:14pm

Title: Engine Spool-Up/Thrust Modeling
Post by bearste on Jan 9th, 2009 at 4:14pm
Hey guys, hope all is well.  I did a search but couldn't find anything on this topic.  I might be nit-picking here, but after spending some good coin and trying to work out several bugs, I am getting more involved with the "aesthetic" working of the aircraft.

I have had the "rat unlocked" problem, solved that by loading FSX up directly to the 757 and saving a flight with both engines running on the ground and a "dark" (clean, no cautions) panel.

I have had the numerous CTD's while programming the FMS, usually at TOD after a long flight, and inputting a new approach.

I have the rocking, although for some reason less violent with the Registered FSUIPC 4.4 version.

I completely changed the soundpack, in fact, yes, I really do fly this aircraft for a US carrier, and find the TSS 767 (yes, I said 767) Rolls Royce model the most accurate for this aircraft.  I have the another company 767 also, because we are dual qualified 757/767.

After all the bugs, the thing that is killing me the most, amazingly, is the engine dynamics. You get to a point and just say, heck, it has bugs galore, but darn it looks good, so please let it act like a 757!  Nope...What is with the immediate sppol-up when adding fuel to the engine on start up.  With the RB211, depending on heat/ambient temp, you will have a "dry spool" for around 30 seconds, then add fuel, and you still have another 25-30 seconds after lite-off for the engine to stabilize.  What we have here is a generic FSX spool-up, which I know can be changed because the another company and another company models accurately represent the start sequence (~1 minute to go from cold to stabilized).

Also, when setting TOGA thrust, the engine spools up rather nicely until ~1.45 EPR, then creeps up to your rate/derate thrust.  The amazing thing is that the slow spool should be on the low range, and the quick spool on the top range!  1.45-1.72 EPR should take a second or two, but in the CS757 you might be at rotation before you achieve proper Take Off thrust!

All right, had to rant...

Everybody enjoy the new year!

JB

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