aircraft container manager

[Henry]

just got a copy the other day
or at least paid for a key
id had it a while to look over
its seems to be great
but i wonder why even planes i have that have gone through this program
by the creator of the air files or cfg files
look like this?
http://i22.photobucket.com/albums/b327/henrybaker/acm6.jpg
http://i22.photobucket.com/albums/b327/henrybaker/acm5.jpg
http://i22.photobucket.com/albums/b327/henrybaker/acm3.jpg
http://i22.photobucket.com/albums/b327/henrybaker/acm2.jpg
and not like this?
http://i22.photobucket.com/albums/b327/henrybaker/acm1.jpg
not picking on the original author
but i have noticed that it changes the areas mesurements
my point is is it better to leave alone or fix it to the model
if anyone here actually uses the program
its awesome for placing fuel, contact points etc etc
H

[Bradburger]

Henry,

IIRC, Jerry said it doesn't matter if the wings, tailplane or fin are not positioned where they should be in RL - that is, matching the actual position of the visual model. All aircraft made with the FDWB and AW will default to the positions shown in your last screenshot.

Maybe he can explain the exact reasons again! :redf:

And you're right about this program.

I wouldn't do without it! No need to bugger about with lights and guesswork to get contact points and other important things positioned correctly! :d

I always set the aircraft up in ACM then import the relevent data into the FDWB or go straight into AW.

Cheers

Paul

[Henry]

Thanks paul!
i kinda figured it didnt do much
because i see no difference in flight
H

[fliger747]

Henry:

Very interesting! I have the download, but not purchased a key so far.

One of the things that drives me wild (probably makes no difference) is that the wings always seem to be located on the cernerline, without regard to their actual position. I usually relocate them to where I think they should be. This seems as if it might be somewhat easier and more accurate.

I am not sure if it does make any difference, though on would hope that it FS flight modeling was sophisticated enough to know the differences, which on a real plane would be considerable. The drag effects of differing wing position can be taken care of other ways, but a low wing should have very differing properties in ground effect in the landing manuver.

Regards: Tom...

[Henry]

its great for lights, effects, station loads etc etc
H

[Farmboy]

Henry:

Very interesting! I have the download, but not purchased a key so far.

One of the things that drives me wild (probably makes no difference) is that the wings always seem to be located on the cernerline, without regard to their actual position. I usually relocate them to where I think they should be. This seems as if it might be somewhat easier and more accurate.

I am not sure if it does make any difference, though on would hope that it FS flight modeling was sophisticated enough to know the differences, which on a real plane would be considerable. The drag effects of differing wing position can be taken care of other ways, but a low wing should have very differing properties in ground effect in the landing manuver.

Regards: Tom...

The location of the wing in Henry's post above (where it has been relocated to what is apparently the correct position) is completely arbitrary because it is based on the model's visual origin. And that is up to the author of the model. The visual location of the wing in ACM has nothing to do with the aerodynamic location of the wing. It's always best for the visual modeler and flight modeler to work together very closely to establish the best compromise position for the model's visual origin so that the ground handling and overall flight dynamics are optimised. Many times, the choice is made to put the vertical center directly through the center of the propeller shaft, as with the model shown above. That makes it convenient to locate the engine and some other things, but results in an apparently incorrect wing location. OTOH, you can locate the model's origin exactly in the plane where the wing is centered, which would result in the wing being correct with no vertical offset, but then the engine location would seem to be wrong because it would need to be located on or near the centerline of the model.

This is especially true of light aircraft; heavy aircraft such as transports and bombers can tolerate more offset of the wing and engines, but these things have to be countered by other adjustments. Sometimes that works out OK, other times it doesn't.

We had a discussion some time ago about building an aircraft entirely of station loads, and what came out of that was that FS9 expects the aircraft to be built as a composite, well-designed airframe. It cannot handle station loads positioned all over the place and still produce good flight dynamics. The same is true with offsetting the wing or engines vertically. A well-designed airframe has been assembled in such a way as to offset to neutral, or nearly neutral, the opposing forces created by the various components. For examply, you can see that in real aircraft, in many or most cases the thrustline of the propeller is offset to some extent as compared to the wing, more so the higher and lower the wing is mounted. The pitching moment of the wing, elevator, and other factors is offset by the location of thrust to produce an aircraft that is relatively neutral and stable under most conditions. Obviously trim needs to be applied within a certain range for special conditions such as high power and angles of attack, or when landing with flaps and gear extended, but the plane is going to be designed so that all forces are generally in equilibrium during the range of normal cruise flight and normal loading.

It is exciting and truthfully a bit romantic and wistful to think that we can assemble all the components in the same way as did the factory and achieve that elusive aerodynamic balance, but in practice, FS9 does not do well when asked to perform in this manner. Firstly it just doesn't perform those calculations especially well, and secondly, asking it to do those calculations uses up processing power! I'm speaking of a case where you might think you've figured out exactly where the center of gravity (and thus the visual model origin) is located on the bare airframe without any engines or equipment installed, and then proceed to try to vertically offset the wing and engine and payloads in such a way as to find that desired equilibrium. It's a tall order and FS9 doesn't usually deliver. The best practice is to locate the model's origin at a good compromise location vertically, and find the wing's 25% MAC location (this can be done with extreme accuracy using standard aeronautical formulae) and make sure the fore/aft origin is located there. Then there is no need to offset the engine or wing on the vertical plane. Ground effects can be adjusted very easily in the .air file to suit each aircraft so this is not a concern.

Of course this is not always true, there are some aircraft that come together quite nicely with offsets but trying to find that magic combination - if it will work at all in FS9 - is generally fruitless. By locating everything in the same vertical plane you are making the aerodynamic assumption of design stability in the airframe as delivered, something quite reasonable, which pilots and passengers do every day when they get into these things and go flying.:jump:

[Henry]

thanks Farmboy
allways helps when someone explaines things
H:ernae:

[KC13]

I downloaded this to have a look, and it's driving me mad. It takes control of the system mouse and slows it to a crawl. For those of you who have purchased a key for this, does that return the mouse to normal operation? If not, then no matter how good a tool this is, and it looks to be great, I'll relocate it to the trash bin

[Henry]

i do not have that problem at all:confused:
H

[Farmboy]

I downloaded this to have a look, and it's driving me mad. It takes control of the system mouse and slows it to a crawl. For those of you who have purchased a key for this, does that return the mouse to normal operation? If not, then no matter how good a tool this is, and it looks to be great, I'll relocate it to the trash bin

It is probably not ACM, but your mouse options. When you open ACM certain mouse software considers it a game because it uses graphics rendering, and if you have your option checked for mouse speed that automatically turns off acceleration for gaming, this would explain the issue. Uncheck the box and see what happens.

[KC13]

It's definitely ACM and it's partner AAM. Both cause the mouse to act like it's swimming upstream in a river of liquid honey. No other graphic program or game exhibits this. gmax and FSDS V3 allow the mouse to operate at my designated speed and acceleration mode. As does Corel Draw and PhotoShop. I'm a computer programmer by trade and this is most likely a conflict with a driver (programmer assumes a Microsoft mouse is always there, but often it's another brand :applause: )
Oh well... <flush> :icon31:

Thanks for trying though.

[sparks]

Hi Henry,

FS uses some, but not all, dimensions in the aircraft.cfg file. I know it uses the following:

aileron_area
aileron_down_limit
aileron_up_limit
elevator_area
elevator_down_limit
elevator_trim_limit
elevator_up_limit
rudder_area
rudder_limit
wing_area
wing_root_chord
wing_span

Wing_area, wing_root_chord, and wing_span affect the aerodyamic performance of the flight model. The control areas only affect force feedback and the control limits affect both the aerodyamics and the animation.

FS doesn't use the vertical locations of wing or tail surfaces, and it doesn't use any of the longitudinal locations of the tail.

Most of the 'unused' parameters in the aircraft.cfg file are there for FSEdit to use in calculating air file stability coefficients.

ACM does a good job of showing you where the empty weight CoG is, but it does not show you where it is when loaded in game due to fuel and station weights and locations.

ACM does not show you where the aerodynamic center is located either, which depends on the air file.

The aerodynamic center and the center of gravity can be located independently, and they can be located anywhere you want them in FS9, regardless of where the visual center of the model is. It's difficult to do because there isn't one single tool that solves the whole problem.

[Henry]

thank you Sir!
its a long learning curve:costumes:
the more i know the more i realise i dont know most of it
but thats life i guess
LOL
H:ernae:

[Bradburger]

FS doesn't use the vertical locations of wing or tail surfaces, and it doesn't use any of the longitudinal locations of the tail.


Apologies, as I missed the word Vertical in my initial post! :redf:



ACM does a good job of showing you where the empty weight CoG is, but it does not show you where it is when loaded in game due to fuel and station weights and locations.

ACM does not show you where the aerodynamic center is located either, which depends on the air file.



According to the ACM website, a new version is due soon.

Maybe these features will be included!

Anyway, thanks Sparks & Farmboy for the info, which, as always, is much appreciated. :jump:

Cheers

Paul

[FelixFFDS]

Another use for ACM is "Instant Paint Kit".

There's a button that appears "UVW Maps" that when clicked, exports a copy of the wireframe mesh .... in other words, you get a snapshot of the wireframe mesh parts.

[Joao Paz]

Hello everyone!

I will have to read this whole thread again and again as there is a wealth of material here... but I just wanted to state my own experience.

I started with flight dynamics a couple of weeks ago; I've been collecting data for my aircraft for a long time now, and the right moment came so I dived in!

At first it was completely nuts but then eventually it all started to fall into place.

One of the very first things that puzzled me was precisely the vertical offsets on some planes, namely the default ones, namely the high wing Cessnas! I was about to concede, but then I loaded many great airfiles into my editor and saw that it was not necessarily so...

Well, it took me a long time to find the correct numbers, but eventually I managed to input what I believe are the correct figures, including the vertical offsets. After a huge mistake with the fuel tanks - that almost led me to quit again - once I corrected it started to fly right away!

I would hate to produce a great arfile I I knew that on its guts it was a mess so I was very happy to find that it was ok to use the real figures also.

Having said this, I must add that the load stations didn't produce the exact numbers (MAC%) as I had found them with a Weight & Balance calculator (and some extra calcs) but they weren't too far off either... so, yes, I adjusted the stations to produce the correct placements of the CoG along the MAC line and she's behaving like a sweet :d

Still a long way to go, though... this is not for the "fainted heart" ... I think this is the expression(?) :isadizzy:


So, right now I'm sticking with the published numbers ... but I saw some good points above hence the further reading I mentioned!

Please do keep up this thread! Most enlightening!

Joao

[sparks]

The location of the wing's aerodynamic center is defined in section 1534. If you want to model a high wing, you'll have to locate the wing's position using this section; otherwise, FS assumes it's at the MDL center. The parameters in this section are relative to the MDL center, which may or may not be the same reference point the aircraft.cfg file is using. Sorry if that sounds confusing, but it is. ;)