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View Full Version : What causes planes or helicopters to bounce or hop while on the ground?



gary42127
October 2nd, 2008, 22:27
I have the Nemeth Designs CH-53, and it bounces around like crazy.

I've downloaded the patches, one of which was supposed to fix this issue.....but it's still bouncing around. It'll scoot right off the helipad eventually.

Any ideas?

kilo delta
October 3rd, 2008, 01:35
Is it just the CH-53 that bounces, or every aircraft? If it's the latter try lowering the Mesh level slider.:)

michael davies
October 3rd, 2008, 02:24
I have the Nemeth Designs CH-53, and it bounces around like crazy.

I've downloaded the patches, one of which was supposed to fix this issue.....but it's still bouncing around. It'll scoot right off the helipad eventually.

Any ideas?

Nine times out of ten its a gear compression ratio problem, or a aircraft MOI issue, on helicopters its good to keep ther MOIs as low as possible to make them agile, however low MOIs also make them fidgity when on the ground.

You may find altering the fuel or cargo weights will make a difference, some models will fidget with a light load but be ok with full loads, others are the reverse.

You need to look very closely at the model and see which wheel is fidgiting and which way ( laterally or vertically ) , the Apache I did used to fidget on the tail wheel but in a lateral manner, ie skip from side to side, a slight increase in yaw MOI and a adjustment to the tail wheel compression value fixed that, but it only happened at certain weights and certain airfields, generally it'll be worse on hard surfaces, grass and dirt sometimes soften it enough not to misbehave.

Best

Michael

gary42127
October 3rd, 2008, 02:29
Is it just the CH-53 that bounces, or every aircraft? If it's the latter try lowering the Mesh level slider.:)

I've noticed it on other aircraft as well, but the CH-53 seems to be more pronounced than the others.

I have all the sliders maxed out except for detail radius which is in the middle. I'll lower the mesh level a bit and see if that changes anything.

gary42127
October 3rd, 2008, 02:34
Nine times out of ten its a gear compression ratio problem, or a aircraft MOI issue, on helicopters its good to keep ther MOIs as low as possible to make them agile, however low MOIs also make them fidgity when on the ground.

You may find altering the fuel or cargo weights will make a difference, some models will fidget with a light load but be ok with full loads, others are the reverse.

You need to look very closely at the model and see which wheel is fidgiting and which way ( laterally or vertically ) , the Apache I did used to fidget on the tail wheel but in a lateral manner, ie skip from side to side, a slight increase in yaw MOI and a adjustment to the tail wheel compression value fixed that, but it only happened at certain weights and certain airfields, generally it'll be worse on hard surfaces, grass and dirt sometimes soften it enough not to misbehave.

Best

Michael

Thanks for the tips. :)

Lateral-G
October 3rd, 2008, 07:55
Bouncing planes were always a problem in FS9. I've had the same issue to a lesser degree in FSX. I think it's an issue with the sim.

There never was a fix for FS9. In some cases it was so bad if you had crash detection on you would never be able to get off the ground.

-G-

michael davies
October 3rd, 2008, 08:07
Bouncing planes were always a problem in FS9. I've had the same issue to a lesser degree in FSX. I think it's an issue with the sim.

There never was a fix for FS9. In some cases it was so bad if you had crash detection on you would never be able to get off the ground.

-G-

With respect, all bouncing / jittering on the ground is fixable, through either landing gear configs or MOIs or correctly set up FDEs.

One set up might not do all global locations but a good set up can resolve a very high percentage of them.

Best

Michael

Lateral-G
October 3rd, 2008, 09:56
With respect, all bouncing / jittering on the ground is fixable, through either landing gear configs or MOIs or correctly set up FDEs.

One set up might not do all global locations but a good set up can resolve a very high percentage of them.

Best

Michael

EVERY aircraft I had in FS9 would "bounce" on the ground at one point or another. Even the default ones. It was a chronic problem that was discussed on all the FS forums at the time. No one ever had a fix for it. (that I am aware of)

To be fair most users are/were not adept at tweaking each and every cfg file to eliminate it (if it is indeed possible, and I'm not saying it isn't but after several years I've yet to see a fix for it).

I experience the "bounce" on most every aircraft in FSX as well but it occurs to a significantly less degree than what it was in FS9. Sometimes switching locations or re-loading the aircraft clears it up. Sometimes it doesn't. If it is a cfg file issue then it would seem once you 'tweak' it properly it should go away. However, as I experience it as a random issue I'm not sure just a cfg 'tweak' will cure the problem.

respect,

-G-

michael davies
October 3rd, 2008, 10:00
Well maybe I'm lucky, I've yet to experiance ground jitters in FSx and only rarely in FS9, each case fixed by adjusting the MOI or gear configs.

I'll just make sure I dont change anything soon :).

Best

Michael

Wozza
October 3rd, 2008, 19:58
EVERY aircraft I had in FS9 would "bounce" on the ground at one point or another. Even the default ones. It was a chronic problem that was discussed on all the FS forums at the time. No one ever had a fix for it. (that I am aware of)



-G-
Hi
This is what I call mesh bounce.What happens is you load the sim in the VC/2d pit,then cycle the view to tower view.The POV in the sim expands quickly and the sim lags the mesh calculations cant keep,then you goto the external view and the sim has to re map the mesh.
Cheers
Wozza

fliger747
October 3rd, 2008, 21:04
As MC iterates, most high Herz bouncings can be fixed by adjusting the gear compression ratio and dampening rates.

FS does have some wierdly possible flubber effects.

T.

heywooood
October 3rd, 2008, 21:18
Hi
This is what I call mesh bounce.What happens is you load the sim in the VC/2d pit,then cycle the view to tower view.The POV in the sim expands quickly and the sim lags the mesh calculations cant keep,then you goto the external view and the sim has to re map the mesh.
Cheers
Wozza


Thats the best way to explain it right there Wozza

Since installing the latest Nvidia drivers however - the 'texture dump' as I used to call it or mesh lag from cycling through the views - is Gone.

I highly recommend the 178.13?... I think is the version number - if you are Nvidia powered - this new driver seems to have corrected the FSX view switching texture dumping lag bounce majigger :ernae:

gary42127
October 4th, 2008, 00:57
I made some adjustments to the MOI and compression ratio today, and the CH-53 no longer bounces and slides around. :)

Thanks again for the tips. :wavey:

IanP
October 4th, 2008, 06:05
Any chance of telling us what tweaks you made, please? :)

Ian P.

michael davies
October 4th, 2008, 06:57
I'm going to guess he added may be 3-6,000 onto the MOIs and increased the compression ratio values by about 0.2-0.3 ie softer.

Best

Michael