elevator and trim give ridiculously high airspeeds.
Increase the elevator effectiveness slightly.
Increase the vertical stabilizer effectiveness, and give it a 1.5
degree incidence angle, to compensate for asymmetric propeller
effects.
Increase the rudder effectiveness to help with cross-wind takeoffs and
landings.
Here're some updates for some of the instruments, the TSR2 and the B52.
The instruments are just parameterised/non-specific versions of the engine
and fuel gauges. The old gauges will still be used by the a10s and the sea
hawks until I get them done.
There're a couple of tweaks to the tsr2 yasim config and amendments to the
model file to change the angle at which the airbrakes operate, correct the
direction that the nose gear retracts/extends and to rotate the main-gear
carts during retraction/extention. There're also new panels, using the new
instruments.
The b52 yasim config has some big changes due to finding some more info i.e.
wing incidence of 6 degrees, fuel capacities and aileron changes (removed
from G & H versions!). It's now based on an 'F' model and I've put some
comments in the yasim config about it. The b52-readme.txt includes a
suggested method on getting airborne;). I've included an amended model -
B52-F.3ds, which is the default in the new model file, and a couple of panels.
I'm quite pleased with the b52 - the take-offs resemble the photographs I've
seen and I think I've got reasonable values where I've had to guess at stuff,
but the results from the yasim solver look as through the model is
approaching the limits of acceptability for yasim. By this I mean that the
model is probably a bit dodgy, not that the yasim solver is limited.
speed/cruise speed setting was better and I've reverted to that - they were
too fast at altitude:) They are closer using Andy's figure.
They don't quite have the required range though:(
There's now another a10 variant - a ferry load configuration - no weapons but
3 x 600 us gal external tanks. This seems to be the heaviest confguration
for an a10. I also found a performance graph for the a10 in clean
configuration and it showed max speeds of 275 knots at 45000 ft and 398 knots
at 1200 ft. As things seem to get a bit squiffy above 35000 ft, in my
experience, I used the 1200 ft figure. This is pretty close the the figure
that Andy Ross found (380 knots at 0 ft) and I've also tried to incorporate
his mods into the new configs, with a better balanced wing/hstab settings.
After getting a good clean config, I added the extra masses/fuel
tanks/fueselages but didn't change any of the rest of the config, and it
still seems to work properly. The external tanks were done as fuel tank
entries, with corresponding fuselage entries, whereas I'm not sure how to
handle the 'weight' entries in yasim yet so the weapon load is still done
with an increased total mass and ballast entries.
There'll be some stuff in the archives that haven't changed i.e. the cl & wl
a10 and seahawk models, but until I get using cvs for my own bits and pieces
it was easier to do the whole directory. I hope this isn't a problem.
Finally, I've set up some panels, based on the c310 vfr and mini panels. The
vfr panels have a lot of additional instruments on them but impose quite a
high frame-rate hit on my system. The mini panels also have some additional
instruments but seem to work without noticable penalty here. I've set these
panels as the defaults for these aircraft but I'm not sure it's a good idea
to have the vfr panels by default due to the performance hit. Using them as
default will should give some feedback though;)
To go with the new panels are a number of rough and ready instruments I
hacked, mostly out of one of the rpm gauges, but I've adapted the throttle
quadrent (jet-throttle-quadrant) to funstion for throttle, flaps and reheat.
All the gauge faces were based on an existing ffgfs instrument texture, so
there's no problem with copyright there. All the other bits that I've done
may be distributed under the same conditions as fgfs.
The only real changes to the seahawk stuff were to add the panels, but I
found that Sea Hawks have three fuel tanks, with a 'saddle tank' over the
engine feeding fuel into the second/rear tank, so the yasim config's changed.
Here are some more updates, and bits and pieces.
The tsr2 is mostly a re-write, with more reasonable figures for the wing and
hstab. I've also tried to reduce the poly count on the model whilst adding
the airbrakes and canopies.
Finally, I've set up some panels, based on the c310 vfr and mini panels. The
vfr panels have a lot of additional instruments on them but impose quite a
high frame-rate hit on my system. The mini panels also have some additional
instruments but seem to work without noticable penalty here. I've set these
panels as the defaults for these aircraft but I'm not sure it's a good idea
to have the vfr panels by default due to the performance hit. Using them as
default will should give some feedback though;)
To go with the new panels are a number of rough and ready instruments I
hacked, mostly out of one of the rpm gauges, but I've adapted the throttle
quadrent (jet-throttle-quadrant) to funstion for throttle, flaps and reheat.
All the gauge faces were based on an existing ffgfs instrument texture, so
there's no problem with copyright there. All the other bits that I've done
may be distributed under the same conditions as fgfs.
The other stuff isn't really an update but something I did for a bit of a
laugh. The idea ocurred to me after animating the folding wings on the
seahawk and seeing that the aileron and flap axis still worked...
Here're a couple of updates. Well, one's an update - the tsr2 and this now
has reasonable wing and hstab values. The roll rate was very high and I
figured that as it was going to be a hack anyway, due to the all moving
tailplanes, I just made them very ineffective and linked them top the
tailplanes in the model file. I think I may have over factored them a bit
too much but it's interesting watch them in chase view. If the autopilot
roll-out-deg is dropped to about two it'll start oscillating, and from behind
it looks like it's paddling:)
and crash on startup. The defaults tend to assume that load is borne in
proportion to the gear's distance from the c.g., but taildraggers are more
complicated. Increase the spring strength.
Here's a B52-H that I've done and it can be distributed under the same
conditions etc. as fgfs. It seems to fly ok but I'm sure it could do with a
bit of adjustment - perhaps Andy R. will have a look and give it a few tweaks.
It wouldn't need too much work to convert it to an -A model (different
engines, taller fin etc.) and then it could be teamed up with the X15 :)
I still can't get textures on the models but it occurred to me that if
someone could apply blank texture maps to the models I could then fill in the
blanks, as it were.
I also noticed that there don't appear to be models included for the F-104,
F-15 & F-16 and I think I could probably do some and animate them for fgfs if
they'd be useful.
Re the A10 - Andy said he'd had a look at it and made a few changes to fix a
few things that I'd done incorrectly and asked if I wanted to keep tinkering
with it or should he roll his changes into the fgfs cvs? I said to him that
I'd be happy to go with his changes as they'll be more realistic/accurate than
the stuff I've done.
I've certainly no problem with anyone doing anything with any of the stuff
I've done, so long as it's an improvement :)
I've taken the liberty of attaching a .tar.gz file containing a .3ds model of
a BAC-TSR2, a yasim config file based on the correct figures (where I could
find them) and the -set.xml and model.xml files to fly it.
I'm primarily a 3d'er and originally did the TSR2 for a picture I'm working
on but when I got fgfs running (Debian Linux) I couldn't resist loading it in
and trying to get it to fly. The model was created in Realsoft3D and
exported as .3ds.
I've been able to tag the various sub-objects, to animate them but the export
process appears to 'flatten' any object hierarchy I set up and I'm guessing
this is necessary for sequential animations - I couldn't set up the correct
sequential rotations to properly bring the main u/c in. Also, in real life,
there are several other u/c doors that should open and close in sequence to
get the gear in and apparently the sequence was quite complex.
On the ground though, it is as shown (so I didn't need to model the extra
doors for my picture anyway;)
It could do with some airbrakes too, both for the model and for the fdm. As
with the extra u/c doors, I didn't need them for the picture and they haven't
been modelled.
As well as not being able to preserve object hierarchies when I export from
Realsoft3D's native object format to .3ds, I'm not able to preserve textures
or colour-mapping either, so the aircraft appears all white.
Hopefully, someone might like to add the extra doors and airbrakes, which
shouldn't be too difficult, and put some texturing on it - mostly white
anyway, for the prototypes, or a contemporary RAF scheme if someone wants to
pretend that it entered service.
The yasim fdm model, as said, cannot be regarded as accurate. However, while
it is based on the specs for the real aircraft, where I could find them, the
measurments are probably only accurate to about 1 metre. That's assuming I
was measuring the right things in the first place;) Other bits that I wasn't
sure about i.e. flaps, ailerons etc. have been hacked out of the a4 or the
747.
It could do with some 'refinment' by people who know what they're doing, but
it seems to fly about right, or rather, as I'd imagine:) (me want a
forward-looking ski-toe terrain avoidance radar:)
Anyway, I'm happy for the whole lot to be released under the same licence and
conditions as the rest of the fgfs stuff, either as a part of fgfs or by
anyone else who will also follow those same licence and condition terms.
I've also got a reasonable yasim b52 flying but no moveable bits on the model
yet, a vulcan with a similar simple 3d model using a grossly hacked c310
jbsim fdm (right numbers where I could find them but powered by a couple of
XLRs) and a Saunders-Roe SR45 Princess flying boat model and yasim fdm (can't
get it into the air with propellors but substituting equivilent jets (2.5x
factor) got it flying. I've started on a EE/BAC Lighting FMk6 model but I'll
probably be doing a Fairchild A-10 and an Antonov An-225 first.
I figure this is the best way I can contribute to the fgfs project, and l'd
like to be able to offer something.
Added property-controlled pylons to the A-4, for external stores modelling.
The harrier now has working auto-stabilization, making it *vastly* easier
to control in hover and slow flight.
is the same "wrong sign" issue that affected the wing location). Adjust
the ballast accordingly. Tune the surfaces a little bit. Also adjust the
location of the tail wheel, presumably to get the on-ground orientation right.
makes ground handling more realistic -- the tail comes off earlier due
to stability effects, and the extra aerodynamic stability (and the
extended rudder arm) makes the aircraft more controllable and less
likely to ground loop.
Try the following patch to c172.xml, which makes the takeoff-rpm
modification I talked about*. Hopefully things will be more to your
liking; the aircraft maxes out at 2100 RPM while stopped, then the
speed increases to something more like cruise as the airspeed grows.
If you look carefully, you'll actually see the RPM drop very slightly
before it starts increasing. The physical reason for this is that the
blades are "unstalling". As the flow attaches to them, they
experience a sharp increase in induced drag. I was pretty pleased to
notice this little tidbit; it kinda validates the model in an obtuse
way. That being said, I have *no* idea if this effect is noticeable
in a real aircraft. Alex?
