Centre of Gravity...

[Fozzer]

FS 2004: Cessna 150 Aerobat. C150_v2.

Hello all...
As

[Strategic Retreat]

I fear you must search for another C152. The center of gravity specified in the .AIR file, and the corrections inside the Aircreft.CFG only use it as a reference point for the rest of the various parameters. :-/

Usually, this kind of out-of-whack gravity happen in planes coming from another version of FS, in this case I believe from FS2002. Try finding a FS9 native C152 (I have and desultorily use the F1 one, so can't really suggest you one).

If you can't or don't want to find another C152, try in the Aircraft.CFG playing around with the parameters reference_datum_position= and empty_weight_CG_position= under the [WEIGHT AND BALANCE] section, changing values and then loading the plane into FS to check the new CG point. But KNOW since now and before starting mucking with it that is never a sure deal. It may work if the .AIR files allows it, it may NOT work, or it may even backfire, needing you to shift other Aircraft.CFG parameters around to make that 152 flyable again with the new CG position.

Before starting to muck around, remember to make a backup copy of the Aircraft.CFG, for immediate rollback purposes, should your tweaks not sort the desired effects out.

P.S...I've suddenly noticed that whilst supping a few glasses of California's best Red Vino whilst preparing Sunday Dins, that my own personal centre of gravity has also shifted slightly to the left!
...HIC!... ... ...!

Ah... never checked that wine out, since my land (Italy) is wine land par excellence. I simply suggest that if normally one is used to drink beer while dining and desires to step up to wine, one has to keep in mind that the fermented grapes juice has an average stronger alcoholic content than beer, and this one must go easy on it on first until some resistance up can be built.

[garryrussell]

Why not just some weight in the rear most position

Just like they use ballast weight in real life

You could also remove your pilot weight

It doesn't really matter what figures are in there as long as it gives you what you want.  It's an easy fix and adjustable

[Fozzer]

[quote]Why not just some weight in the rear most position

Just like they use ballast weight in real life

You could also remove your pilot weight

It doesn't really matter what figures are in there as long as it gives you what you want.

[microlight]

Greetings, Paul.

Which version of the FDE are you using? Mine is dated April 2007 in the aircraft.cfg header. I just reset the loading figures to match yours (I'm a little heavier than you!) and the CoG is still exactly where it should be.

You can indeed modify this yourself from the aircraft.cfg quite easily; look for this line in the [airplane_geometry] section.

wing_pos_apex_lon = 2.23

Maybe you can confirm what value your line is set at? Increasing the positive figure moves the CoG backwards towards the tail, so try increasing in increments of 0.1 until it's where it needs to be. This is a quick-and-dirty method (it amends where the position of the wing apex is along the plane body) without having to look into what the rest of the FDE is doing, but any errors that this particular change induces aren't noticeable (to me, anyway). I think I must have done this myself when I got the plane as with this setting, not only is the CoG where it should be, she takes off at full throttle, no flap at 80kts at centre trim with just a gentle pull back on the yoke, just as you'd expect.

Let me know how you get on.

[Capt.Propwash]

go on the main website, and search for AIR EDITOR.

[microlight]

I'd advise caution when fiddling about with .air files, for two reasons.

First is that even with AirED (which I also use), many of the .air file functions are to this day unknown outside Microsoft - and represented as s in the appropriate AirED fields - so unless you know exactly what you are doing, you can do more harm than good.

Second is the fact that in the main, the more common settings in the .air file are directly modified by the .cfg file during loading. FS9 loads the .air file first and then modifies its settings with the equivalent settings in the .cfg file, so that modifying the .air file in FS9 (and even in FS2002/FS8) becomes largely redundant in these cases - which practically speaking is most of the time. I've proved this by creating a L1011 trijet FDE using the default unmodified 747 .air file, and the resulting L1011 operates as it should. Same with a 727 using the default 737 .air file.

So while programs like AirED are great for modifying the parameters that the .cfg file doesn't touch - and of course there are some - developers indeed know which these are, which to stay away from and which are modified by the .cfg file, so that they don't waste time and effort.

[Fozzer]

Greetings, Paul.

Which version of the FDE are you using? Mine is dated April 2007 in the aircraft.cfg header. I just reset the loading figures to match yours (I'm a little heavier than you!) and the CoG is still exactly where it should be.

You can indeed modify this yourself from the aircraft.cfg quite easily; look for this line in the [airplane_geometry] section.

wing_pos_apex_lon = 2.23

Maybe you can confirm what value your line is set at? Increasing the positive figure moves the CoG backwards towards the tail, so try increasing in increments of 0.1 until it's where it needs to be. This is a quick-and-dirty method (it amends where the position of the wing apex is along the plane body) without having to look into what the rest of the FDE is doing, but any errors that this particular change induces aren't noticeable (to me, anyway). I think I must have done this myself when I got the plane as with this setting, not only is the CoG where it should be, she takes off at full throttle, no flap at 80kts at centre trim with just a gentle pull back on the yoke, just as you'd expect.

Let me know how you get on.

;)

Hello Micro... :)..!

Ta for the response!

This is my default setting in the C 150 Aircraft file...>>>

"wing_pos_apex_lon

[Fozzer]

...PS....

Wonderful stuff, Micro!... ...!

Just omitting the "Minus" sign positioned me back in the Pillocks Pilots seat again, aft of the engine.

"wing_pos_apex_lon

[microlight]

Paul,

Glad your problem's fixed - happy to be of service!

Cheers,
Martyn