Thanks for the information Andrew. I just went to the flight dynamics that came with the IFDG 757 and this is what the aircraft.cfg file says:empty_weight = 170000.000There must be some reason that this value was used. Could someone please help me to understand if the typical OEW is 130,000 pounds?Please keep in mind that this is the first AIR file I have modified, and I am still very new to the subject.Thanks for all the comments and suggestions.-twilky

OEW = Operating Empty WeightThis is the airframe + crew weight... no passengers, no fuel.The figure that MS refers to as empty_weight can mean two things depending on how you decide to model C.G. In this case, it is actually the ZFW (Zero Fuel Weight, OEW + Payload, no fuel). Another option is to model individual passenger rows and cargo bays by adding several station load points along the assumed cabin floor plan. I'm not convinced that station loads are accurate enough to model C.G. correctly or even worth bothering with in FS2K2. By adjusting these figure you can simulate differing payloads for each flight which in turn affects performance.A ZFW of 170,000 assumes a payload of approximately 39,000 LBS. This assumes 185 or so passengers (approx 210 lbs per passenger including luggage).

That must have been the reason I thought the OEW was higher than it was. Thanks for explaining.

Twilky, So if the ZFW used in the .cfg is 170000lbs, then add 22000lbs fuel to that and you're up to 192000lbs total. Now looking at the handy chart Mr. Reynolds provided, at sea level a 757 with a gross weight of 180000lbs should climb at about 4600fpm at max climb thrust. Now I was using CLB2, and I also weighed 12000lbs more than the weight in the chart, and I was climbing at over 4000fpm. Doesn't sound quite right to me. Keep in mind I'm not bashing you're work at all. I want a very realistic-performing 757 just like you, and that is why I post these messages.Ryan Hoffman

Another thing I noticed that was really puzzling was the IAS at altitude...cruising at FL350, mach .80 I was getting an IAS of about 304kts. From my experience, that is way off. I really have no clue as to why this would happen...maybe something to do with a change made to the amount of drag the plane experiences? Just a guess.Ryan Hoffman

I plan to try modify my AIR file a little tonight, with the climb rate chart alongside me.RyHoffman:Your guess is as good as mine with the IAS. I'll see what I can find out.-twilky

I just went and played around with my files. I found that my climb rates are about 300-500 higher than the chart, with a cost index of 80. Also, the amount of work required to change the climb rates would be a substantial amount. It would require changes in MANY values to counteract the change in engine thrust. I, personally, am not willing to sacrifice this much time (especially considering midterms are coming up in a week) over a couple hundred FPM.Thanks for all the comments. Feel free to keep posting.-twilky

Actually it's not difficult at all but will take an hour of your time going through takeoff after takeoff. It does not require a change in engine thrust rating, but a reduction in thrust scallars for N1 at Mach 0.0 and 0.90. Lift Induced Drag would also play an important role at high altitude.

I've spent some time revising my AIR file, and am preparing a second version to be released. I've managed to get the climb rates to be right on, and am looking for a list of other improvements I can make for my new release.Thanks.-twilky

Unfortunately, during testing of the new revised dynamics, the change in the climb rates has aversely affected the realism of the rest of the aircraft. The problem with the IAS has gotten worse, along with a couple other issues. I, myself, do not have the time to try and work through these bugs, so for the time being, the flight dynamics are as is.-twilky

Guys, my iFDG Gmax 757 (Transavia) will be out shortly and I have recreated the entire FDE for it. I spent countless hours on it and have it near perfect as much as I can, based on my QRH and own experience. It will feature:- accurate climb performance from SL to FL420 at all weights- accurate descent performance from FL420 to SL at all weights- accurate speedbrake characteristics- accurate acceleration and deceleration rates- idle thrust taxi at low weights and thrust required at higher weights, just like the real thing- accurate fuel flows for the entire flight regime except taxi (impossible for me to modify but oh well)She flies a very steady approach, even manual and single engine. For the first time, she's hard to slow down during the approach so it requires descent planning :)Plus, she integrates perfectly into 767PIC, although fuel flow figures by the FMC are incorrect, it just goes with the territory. Entering ZFW = 130t (metric) will give you spot on performance figures, VNAV data and ref speeds.Iz

Excellent Iz---I hope that they live up to your description, because if they do, we will have found our perfect 757!-twilky

Iz, if you're dynamics are all you say then you are my new hero.Ryan

No desrepect to anyone here but the fact that Iz is a 757 F/O makes me trust whatever he has to say about his 757 preformace numbers! And if it works very well with the PIC panel he will also become my new demi god LOL. Now get to work Iz so I can use it with my newest VFR panel!Best Wishes,Randy J. [email protected]" A little learning is a dangerous thing"

IZ.... One question ? ZFW 130t metric puts the 757 at about 285000 lbs . Is this right or do i have my numbers mixed up .Thanks