When planes bounce: aircraft.cfg files

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When planes bounce: aircraft.cfg files

Postby Hoorf » Sun Dec 30, 2018 5:50 am

Here's one I couldn't find: whenever I load up Flight Sim 2004 and certain small aircraft to go flying, as soon as the plane loads onto the screen, it seems to fall from a couple feet up and bounce on the ground, sometimes with enough force to break a gear or two. It doesn't do this with standard FS2004 aircraft, only some add-on aircraft. Has anyone dealt with this issue, and how does one fix it? I have Aircraft Container Manager and know how to use it for many things excepting the controlling of the start-up drop (and a few other things). Thanks!
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Re: When planes bounce: aircraft.cfg files

Postby B0ikat » Sun Dec 30, 2018 9:01 am

It's most likely a problem with the landing gear contact points. You have to experiment with them o find the correct values,
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Re: When planes bounce: aircraft.cfg files

Postby Hoorf » Sun Dec 30, 2018 5:29 pm

That's one thing I have been doing, and ACM has been great for helping me to visualize the values against the model as I adjust said values...but no matter what, I still get that "drop" on loading and sometimes it's worst when I fire it up after sitting idle awhile. I've even adjusted the model's empty CG to actual aircraft specification (but not the model's reference-point center), fuel stations, engine station, passengers & cargo. One issue with the Grumman AA1 has been the fact that it's been tail-heavy out of the box and likes to ride the mains too long on landing, and the nose must be forced down. That much has been remedied, guess I'll keep doinking with it. Danke!
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Re: When planes bounce: aircraft.cfg files

Postby Hagar » Mon Dec 31, 2018 10:28 am

I think you need to edit the static_pitch= & static_cg_height= values in Aircraft.cfg.

Here's a little trick I discovered some years ago when creating my own aircraft for CFS2.
It was extra important in CFS as if you got these values wrong the aircraft would blow up on loading a flight. :shock:

Start FS9 & select the problem aircraft in Free flight. A default airport would be the best location. Load the flight & go to Spot View.
Here's a shot of a 3rd party aircraft I had installed which is a good example of the problem. Looks OK so far.
Image

Now press the Y key to go into Slew mode. The problem becomes evident.
The tail is in the air & the wheels are off the ground causing the aircraft to drop while loading.
Image

I corrected the static_pitch first before correcting the static_cg_height.
This is a matter of trial & error & unfortunately involves exiting FS9 each time before editing the CFG.
It gets easier with practice & for convenience I use the Previous Flight option from the Select a Flight menu each time I restart FS9.

In this case I changed the static_pitch= value from 0.000000 to 8.500000 & static_cg_height from 7.089000 to 5.5000
This is the result in Slew mode. Problem fixed. 8-)
Image

Note: You might need to change the Aircraft Realism settings to avoid damage while tweaking the CFG
My example is a taildragger & involves positive static_pitch values. For nose down angles use negative values.
It's a long time since I used ACM & I don't know if these values can be edited within the utility
Image

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Re: When planes bounce: aircraft.cfg files

Postby Hoorf » Mon Dec 31, 2018 2:27 pm

Hagar wrote:I think you need to edit the static_pitch= & static_cg_height= values in Aircraft.cfg.

Here's a little trick I discovered some years ago when creating my own aircraft for CFS2.
It was extra important in CFS as if you got these values wrong the aircraft would blow up on loading a flight. :shock:

Start FS9 & select the problem aircraft in Free flight. A default airport would be the best location. Load the flight & go to Spot View. Here's a shot of a 3rd party aircraft I had installed which is a good example of the problem. Looks OK so far...Now press the Y key to go into Slew mode. The problem becomes evident. The tail is in the air & the wheels are off the ground causing the aircraft to drop while loading.


Shaboom, shoobah, that's it! #nailed

Hagar wrote:I corrected the static_pitch first before correcting the static_cg_height.
This is a matter of trial & error & unfortunately involves exiting FS9 each time before editing the CFG.
It gets easier with practice & for convenience I use the Previous Flight option from the Select a Flight menu each time I restart FS9.

In this case I changed the static_pitch= value from 0.000000 to 8.500000 & static_cg_height from 7.089000 to 5.5000
This is the result in Slew mode. Problem fixed. 8-)
Image


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Hagar wrote:Note: You might need to change the Aircraft Realism settings to avoid damage while tweaking the CFG.
My example is a taildragger & involves positive static_pitch values. For nose down angles use negative values.
It's a long time since I used ACM & I don't know if these values can be edited within the utility


The values are in ACM, for sure, in the Parameters>Contact points section; AA1 pitch was fine, but height was not, so it got fixed. I HIGHLY recommend Aircraft Container Module for anyone here who wants to delve into the wild world of tweaks and fixes!
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Re: When planes bounce: aircraft.cfg files

Postby Hagar » Mon Dec 31, 2018 2:44 pm

Excellent. Looks like we have a result. :)

Hoorf wrote:The values are in ACM, for sure, in the Parameters>Contact points section; AA1 pitch was fine, but height was not, so it got fixed. I HIGHLY recommend Aircraft Container Module for anyone here who wants to delve into the wild world of tweaks and fixes!

Indeed. I've just been playing with ACM. Found quite a few aircraft where those parameters are way out. Once you know what to look for it makes the whole thing a lot easier.
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Re: When planes bounce: aircraft.cfg files

Postby Hoorf » Mon Dec 31, 2018 3:36 pm

Thanks again, did a perfect flight from U70 (Cascade, ID) to KMYL (McCall Municipal), rolled around on the north tarmac in the 'sticky' places where the plane used to bounce and gear-break...it's all gone now, zero bounce. Then hit RWY 16, got up, bee-lined past Donnelly, ID (U84, Donald D Coski Memorial) and zinged right back into Cascade (these Grumman Yankees like to approach & land hot, y'know...). Perfect experience. Time to look at all my planes now...esp. the aftermarket ones. Have a fabulous New Year!
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