Re: Tail wheel height off ground

[chucklamb]

This mornng (Aug 6) a Fokker Triplane was available for download. The designer


said that he was releasing it as is and left it to those interested to play
with the settings. I like the way it flys and while a bit touchy can be landed


quite ok with touch down speeds (indicated) in the range 45-50kts. Problem I
face is that at rest the tail skid is, say 1-2ft off the ground. What aircraft


cfg parameter do I change to lower this, please

Clyde W

Try adjusting the Center Gear position +Above/-Below CG in Section 1004

[rayclyde]

This mornng (Aug 6) a Fokker Triplane was available for download. The designer




said that he was releasing it as is and left it to those interested to play
with the settings. I like the way it flys and while a bit touchy can be landed




quite ok with touch down speeds (indicated) in the range 45-50kts. Problem I
face is that at rest the tail skid is, say 1-2ft off the ground. What aircraft




cfg parameter do I change to lower this, please

Clyde W

Try adjusting the Center Gear position +Above/-Below CG in Section 1004

Thanks. I know little of this aspect of simming but am I right in assuming
that the various values are inches(?) plus or minus from the CofG. e.g. Main
longitudinal 24 and Main vertical -59 mean 24 inches forward of the CofG and 59
inches below it? I've managed to get the main wheels 'out of the mud' and the
skid closer to the ground by making the Nose/tail longitudinal = -110 & the
main vertical = -60. If I try to alter the tail vertical to a value plus or
minus the default -29 then the aircraft starts to bounce etc. I guess the
values cannot be altered without being aware of the effect on other values.
Having fun tho' and learning a lot. The aircraft is Jorgen Unschuld's
juredbar.zip on Fsim this morning.

Clyde W

[frfsim]

Also - if you got the main wheels "out of the ground", you can tweak the
"fuselage angle" a negative number gives you a tail down attitude.

Felix/FFDS
Pegasus Aviation Design




This mornng (Aug 6) a Fokker Triplane was available for download. The designer






said that he was releasing it as is and left it to those interested to play
with the settings. I like the way it flys and while a bit touchy can be landed






quite ok with touch down speeds (indicated) in the range 45-50kts. Problem I
face is that at rest the tail skid is, say 1-2ft off the ground. What aircraft






cfg parameter do I change to lower this, please

Clyde W

Try adjusting the Center Gear position +Above/-Below CG in Section 1004

Thanks. I know little of this aspect of simming but am I right in assuming
that the various values are inches(?) plus or minus from the CofG. e.g. Main
longitudinal 24 and Main vertical -59 mean 24 inches forward of the CofG and 59


inches below it? I've managed to get the main wheels 'out of the mud' and the
skid closer to the ground by making the Nose/tail longitudinal = -110 & the
main vertical = -60. If I try to alter the tail vertical to a value plus or
minus the default -29 then the aircraft starts to bounce etc. I guess the
values cannot be altered without being aware of the effect on other values.
Having fun tho' and learning a lot. The aircraft is Jorgen Unschuld's
juredbar.zip on Fsim this morning.

Clyde W

[rayclyde]

Felix

Thank you. Altering the fuselage angle about +2 degrees has made a substantial
difference. Alas, however, the closer I get to the 'ideal' angle the greater
the tendancy to bounce. I will have to do a lot of experimentation I fear.

If it is not imposing too much and if you have the time could you tell me what
exactly causes the 'bouncing' phenomena. I would appreciate that as I could
then start making informed adjustments rather than just 'hit and miss'

Thanks

Clyde W


Also - if you got the main wheels "out of the ground", you can tweak the
"fuselage angle" a negative number gives you a tail down attitude.

Felix/FFDS
Pegasus Aviation Design




This mornng (Aug 6) a Fokker Triplane was available for download. The designer
etc. etc.

[enged]

Felix

Thank you. Altering the fuselage angle about +2 degrees has made a substantial


difference. Alas, however, the closer I get to the 'ideal' angle the greater
the tendancy to bounce. I will have to do a lot of experimentation I fear.

If it is not imposing too much and if you have the time could you tell me what
exactly causes the 'bouncing' phenomena. I would appreciate that as I could
then start making informed adjustments rather than just 'hit and miss'

Thanks

Clyde W

Hello,
I agree with Felix's techniques, but maybe I can amplify on their effects.
Fuselage Angle and CG Height Above Ground seem to affect how the plane enters
upon Selection from the menu. Gear Heights define its ground behavior once it's
already there.
That is, even if you have Gear Heights set perfectly, it'll bounce up or
down a little on entry if the CG Height is off. As I recall, fellow simmer Tom
Goodrick came up with an excellent rule for determining this entry. It's 1440 x
Main Gear Height. Of course, you can fool with the value too.
Putting it all together, if Gear Heights are correct the plane will look
right on a runway centerline when viewed from all directions.
If CG Height and Fuselage Angle are correct, it'll appear stationary from
Menu Selection.
One last comment on bouncing. If it's general (i.e., not just on entry),
then it's a more serious problem with CG, Gear Loading and Damping. I have no
great expertise in this, just fooling around comparing good planes with bad. I
sense, though, that this isn't your problem here.
Hope all this is helpful (and reasonably accurate...).
-- Dennis S, FSEngEd@aol.com

[rayclyde]

Dennis

Thank you for your information. I now have some understanding of the problem,
even though, at this stage, I do not have the answer.

Clyde W