> If this is truly the case, and if it is due to a gear modeling fidelity
> issue, then I agree. But, the kind of problem you describe would be a
> different issue. Since wind effects are only ramped in as velocity
> increases, the example you describe above should not happen with JSBSim.
>
"Jon S. Berndt" wrote:
>> From: Martin Spott [mailto:martin.sp...@mgras.net]
>> BUT, basically, I'd say this is not the point at all - these are
>> interesting theoretical approaches to the problem, but for the 'real'
>> user who's getting veered off the apron while he is simply doing a
>> proper
> From: Martin Spott [mailto:martin.sp...@mgras.net]
>
> This one shows the nose wheel _velocity_ over a timespan, the other
> three diagrams are showing the slip _angle_. To draw a reasonable
> conclusion it would be interesting to see the same measurand, say the
> slip velocity for all of the in
"Jon S. Berndt" wrote:
> The wheel slip angle, for instance, varies wildly in JSBSim when no
> filtering or other compensation is used:
[...]
> If the forces are ramped down to zero below some threshold, the dynamics
> improve greatly:
This one shows the nose wheel _velocity_ over a timespan, th
> > To put it a bit provoking (no personal offense intended!) for the sake
> > of getting the status right, this looks to me that we're never going to
> > have this feature of proper tire/ground reaction simulation in
> > FlightGear simply because the involved folks prefer to play around with
> >
* Diogo Kastrup -- Thursday 05 February 2009:
> The bigger problem with this approach is the Carrier, but I
> don't see why it shouldn't work. Although I haven't got it
> working so far. I hope this can be solved soon, so I can
> send the patch as a proof of concept. IMHO it is working
> pretty wel
Em Qui, 2009-02-05 às 11:34 +, Martin Spott escreveu:
> To put it a bit provoking (no personal offense intended!) for the sake
> of getting the status right, this looks to me that we're never going
> to
> have this feature of proper tire/ground reaction simulation in
> FlightGear simply because
> To put it a bit provoking (no personal offense intended!) for the sake
> of getting the status right, this looks to me that we're never going to
> have this feature of proper tire/ground reaction simulation in
> FlightGear simply because the involved folks prefer to play around with
> smaller,
"Jon S. Berndt" wrote:
>> Well, just very few years ago 'we' (TM) had a patch in our budget that
>> would have allowed JSBSim to do excellent simulation of a tire's
>> contact area. Some of us have seen with their own eyes that the guy
>> (the submitter of the respective patch) obviously knows ab
Maik Justus wrote:
> Hi,
> Melchior FRANZ schrieb am 02.02.2009 18:43:
>> Ever since helicopter support was added to the YASim FDM
>> there's an annoying bug: even when parked, with rotor off
>> and braked, helicopters slide happily around on the ground.
>>
>>
> some time ago I dug into this pro
> Well, just very few years ago 'we' (TM) had a patch in our budget that
> would have allowed JSBSim to do excellent simulation of a tire's
> contact area. Some of us have seen with their own eyes that the guy
> (the submitter of the respective patch) obviously knows about how to
> properly deal wi
> some time ago I dug into this problem and tried to fix it. My idea was,
> to check, if the movement is smaller than a very small number
> "epsilon",
> and if yes, set the movement to zero. The movement need to be measured
> against the ground, which could be the carrier. This should fix the
> sli
Hi,
Melchior FRANZ schrieb am 02.02.2009 18:43:
> Ever since helicopter support was added to the YASim FDM
> there's an annoying bug: even when parked, with rotor off
> and braked, helicopters slide happily around on the ground.
>
>
some time ago I dug into this problem and tried to fix it. My i
"Jon S. Berndt" wrote:
>> * Jon S. Berndt -- Tuesday 03 February 2009:
>> > It's a tough problem, [...[
>>
>> Maybe we should hire a rocket scientist? :-]
> With our *huge* budget? :-)
I may also remind of this related posting, written late in November
2007:
Subject: Re: [Flightgear-devel] s
On Tue, Feb 3, 2009 at 10:50 AM, Jon S. Berndt wrote:
> > * Jon S. Berndt -- Tuesday 03 February 2009:
> > > It's a tough problem, [...[
> >
> > Maybe we should hire a rocket scientist? :-]
> >
> > m.
>
>
> With our *huge* budget? :-)
I have noticed a measurable uptick in FlightGear interest si
> * Jon S. Berndt -- Tuesday 03 February 2009:
> > It's a tough problem, [...[
>
> Maybe we should hire a rocket scientist? :-]
>
> m.
With our *huge* budget? :-)
JB
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On Tuesday 03 February 2009, Melchior FRANZ wrote:
> * LeeE -- Tuesday 03 February 2009:
> > Do you still get problems if you set the windspeed to zero?
>
> Yes. With pretty much the same sliding speed.
>
> m.
That's interesting, and a bit at odds with what I've experienced.
LeeE
---
* LeeE -- Tuesday 03 February 2009:
> I just had a look at the latest version of the bo105 that I have
> here and the is set to 0.5 and the to 0.4, which
> are both lower than default values of 0.8 & 0.7.
I know. But I also tried 1.0 for both (the maximum), and it had
no effect. Other changes
* Jon S. Berndt -- Tuesday 03 February 2009:
> It's a tough problem, [...[
Maybe we should hire a rocket scientist? :-]
m.
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software. With
* LeeE -- Tuesday 03 February 2009:
> Do you still get problems if you set the windspeed to zero?
Yes. With pretty much the same sliding speed.
m.
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On Tuesday 03 February 2009, Melchior FRANZ wrote:
> * LeeE -- Tuesday 03 February 2009:
> > Have the people having bad problems with this tried increasing
> > the values for the & gear sub-elements?
>
> Yes, of course. I really, really hope that I haven't forgotton
> about other, similarly obvio
On Tuesday 03 February 2009, Melchior FRANZ wrote:
> * LeeE -- Tuesday 03 February 2009:
> > Have the people having bad problems with this tried increasing
> > the values for the & gear sub-elements?
>
> Yes, of course. I really, really hope that I haven't forgotton
> about other, similarly obvio
* LeeE -- Tuesday 03 February 2009:
> Have the people having bad problems with this tried increasing
> the values for the & gear sub-elements?
Yes, of course. I really, really hope that I haven't forgotton
about other, similarly obvious things in the many hours that I
tried to fix the problem, o
> In JSBSim we got around it differently by filtering the gear forces (and
> other parameters) at the frame rate, which significantly reduces the
jitter,
> and by also attenuating gear forces (correctly) at low velocity. This
> requires some tuning on a per-aircraft basis, but when given the proper
> Hi Melchior... and Andy
>
> I don't know about helos, but preventing an aicraft to slip on the
> carrier
> is *a real PITA*. The way to fix this leads to unrealistic smooth gear
> struts,
> not to talk about the time consumed.
> Well it may not be a bug in YASim, but actually it's a real unfrien
> Yeah, why not JSBSim? Would be a fine alternative :-)
>
> Well, I noticed today that putting all ballast at one spot helps a lot.
> Means: all ballast used has the same coordinates. I did try this on the
> ec135 and ec130 and it seems to work good. But it don't work on the
> bo105 due to the nam
Melchior FRANZ wrote:
> Ever since helicopter support was added to the YASim FDM there's an
> annoying bug: even when parked, with rotor off and braked,
> helicopters slide happily around on the ground.
>
> Andy knows about it and explained why it happens, but claims that
> there's nothing to
Melchior FRANZ wrote:
> Didn't JSBSim have a similar problem, and fix it there?
No, unfortunately not The visible effect has been reduced quite
efficiently, but the underlying problem is still there. I know of just
one single FDM for FlightGear that does proper modelling of ground
friction
Em Seg, 2009-02-02 às 20:02 +0100, Melchior FRANZ escreveu:
> > The problem is that I have to keep the stuck point moving with the carrier
> > but the carrier "update" is not on the same frequency than the FDM
> > "update".
>
> A dependency on the AI update rate would probably not be very
> welcom
* Diogo Kastrup -- Monday 02 February 2009:
> This patch started just for fun to see if I could help this sliding
> problem, that annoyed me a lot since I love flying helicopters.
A true fix would indeed be nice.
> The problem is that I have to keep the stuck point moving with the carrier
> but
Hello,
I have posted on this list before but I guess I never introduced myself.
I am a Brazilian system analyst with experience in C programming and a
little C++. I have no real pilot experience and no physics formation.
I have a crude patch to improve gear friction in yasim using the method
cite
>Hardly. I can adjust static masses, but not all the additional
>loads. They just are where they are in real life. More or less.
That's why I gave up this idea real fast
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* Heiko Schulz -- Monday 02 February 2009:
> Well, I noticed today that putting all ballast at one spot helps
> a lot. Means: all ballast used has the same coordinates. [...] But
> it don't work on the bo105 due to the named things by m. I guess.
Hardly. I can adjust static masses, but not all the
Hello,
>Has anyone ever found a solution to the gear bug? Something
>that's not a hack? (I'd accept an alternative FDM as well.
>What about JSBSIM? :-)
Yeah, why not JSBSim? Would be a fine alternative :-)
Well, I noticed today that putting all ballast at one spot helps a lot.
Means: all balla
Ever since helicopter support was added to the YASim FDM
there's an annoying bug: even when parked, with rotor off
and braked, helicopters slide happily around on the ground.
Andy knows about it and explained why it happens, but claims
that there's nothing to be fixed in the FDM code. Instead,
he
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