737-700 Minor Bugs

[kevinh 409]

 

 

After takeoff the aircraft is not maintaining a proper trimming position as Kevin and I stated above. I say again, this problem is not happening with other NG variants. All flight I do are planned accordly with real world procedures. Probably the FMC takeoff trim calculation might not be accurate, just saying.

Try all ZF weights. Ex: 51.4 Kgs.

I've tried various weights and flap settings, none give me unusual pitch down after takeoff. It's not exactly in trim but it's close, just as with the other variants.  The FMC stab trim setting agrees well with the FCOM tables.

 

The thing is the stab trim setting gives you an initial trim position. However you are in command and if it's out of trim for some reason you need to adjust. I don't see and error with the -700 version on my installation, never have.

[kevinh 409]

About descent pitch & rate of desc here is a screenshot:

 

 

 

https://fbcdn-sphoto...133082797_o.jpg

Santiago,

 

Two things struck me from your screenshot (which really should have shown weight in the FMC to be more help). Your descent speed is very high and your Vref is very low (108). That is the lowest Vref published for the -700 and equates to a weight of 90,000 lbs at Flap 40. So your aircraft is virtually empty. The descent profile indicates you have a Cost Index of around 100, which is high for a 737.

 

High CI means a very high descent rate. The sim is doing exactly what it should, there is no bug. The low weight also ties in with the stab trim setting you were reporting (4.5 units). I would suggest you fly the -700 at more normal weights and with a much lower CI (I usually use 30). You will also find it much less sensitive in pitch when you takeoff.

 

Kevin

[downscc 1,327]

Yeah, I think the -700 is one of the sweetest to fly. Never noticed a trim problem on T/O (errr... unless I forgot to set it). In reality, if it's in the green band you're good to go. Once airborne trimming becomes so automatic that I never notice it.

[NM5K 1]

I've never noticed any real difference in takeoff trim with any of the four variants.

I fly the 700 the most out of the four, and I might be trimmed just a tad low sometimes,

but only a slight amount to make me a bit below the target looking at the HUD.

And that could be the way I fly too.. I've always tended to fly out just a tad low for some

reason rather than higher. But I can let go of the yoke and still be fairly stable say if going

to LNAV/VNAV at 400 AGL. And all the other variants act the same as I fly them.

It's only after I start picking up more speed that the trim needs to be adjusted a bit.

And I've always set the takeoff trim according to the performance page.

 

Kind of agree about the variants.. The 600 and the 700 are my favorites as far as the

overall feel. The "slipperiness" seems just right. The 600 seems quite realistic, and pretty

much like I'd expect. About like a 500 with a glass cockpit. And as it should be with no winglets,

the 600 is the least slippery of the bunch. The 700 is just a tad more slippery, and I would

expect that being all the ones I run have winglets. I've never actually run the 700,800 or 900

non winglet versions. Not even once..  :/  When I go to the 800, it feels quite slippery in comparison.

Maybe even more than the 900, but I've never really done a hard comparison between the two

longer models to see if the 900 is as slippery as the 800 feels.

 

As far as CI, when playing Southwest buoy, I've been using 36-38 lately.  Don't have a clue

what they actually use in the real world. When I fly the private 600, I usually run about 45.

I like to see in the mid 290 knot range + - as far as the climbs to cruise.. And I adjust the CI for

that. Usually the descents will be around 282-284 + - for the 700, and around 290 for the 600 if

the CI is 45.

[squerble 300]

As above, it'd be great it you could post your Cost Index for the above flight. I haven't used much above CI26 when I last flew the NGX and I don't ever recall seeing such high speeds.