FlightGear - Création d'avions et autres / Creation of aircraft and other

Vous désirez aider à améliorer les avions de Hangar de Helijah, c'est ici que cela se passe / You would like to help improving aircraft from Helijah's hangar, this is where it happens

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#1 2015-03-23 15:42:01

D-ECHO
Créateur
Inscription : 2014-10-28
Messages : 125

EchoAir Xperience

Here is the next aircraft from "EchoAir Aircraf": The Xperience:
https://www.dropbox.com/s/xwkic6bo7lhh9 … h.png?dl=0
Im already at the state you see in this pic:
https://www.dropbox.com/s/5etzzoozh49ao … 0.png?dl=0
But Ive got a problem with the FDM: I took the FDM of the Tecnam P2010 for testing, and everyone worked fine (except wrong position of aircraft).
Then, when I set the wheel coordinates to the right one of the aircraft, the aircraft doesnt move anymore...
Can anyone of you help me with this?

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#2 2015-03-23 16:47:52

Didier1963
Developpeur
Lieu : Poitiers
Inscription : 2012-10-24
Messages : 1 233

Re : EchoAir Xperience

Most probably because the coordinate of the wheel is below the theoretical ground level.
So too much pressure and lot of power needed to pull the plane.

Do you know how to take coordinate of an object with Blender?

You have to make the difference between your 3D plane & your YASim plane.
3D plane is whatever you modeling with Blender, could be a sledge hammer, or my next project for the fun for my soon:

lego-910.jpg

Then you have the YASim plane,
the one for witch you define measures in the FDM.

If you want to enter coordinate extracted from your Blender plane, be sure that it's gravity center is located at the right position.

In your FDM eax-yasim.xml (choose a chort name for your files it is easier)

I will have to check in my file translated from Bukkaro's tutorial, because that's long time I did not work on a FDM, but ruffly it is something like that

check the following lines :

<cockpit x="0.000" y="0.000" z="0.000"

that's ruffly where you tell him where will be the pilot eyes.

<fuselage ax="14.30" ay=" 0.00000" az="-1.16000" bx=" 8.98000" by=" 0.00000" bz="-0.24700" width="3.75" taper="0.25" midpoint="1.00"/>

you will need fuselage lines to define the plane volumes, mostly the fuselage itself, the engine(s) and different parts

ax, ay, az : being the front tip of the volume
bx, by, bz : the end tip of the volume
width : self explanatory
taper : if I remember, the height of the volume, I'll have to check.

Then you must define the half wing (the FDM will calculate the other half) in the line
<wing.....
x,y,z the center of the wing base (y=0 in your case)
chord : the height of the base
length : the length of the base
sweep : the angle in ° of difference between the wing base & the wing tip (generally only 2 or 3)
dihedral : the angle between the wing base and the wing tip, I'll have to check
taper the angle in vertical between the horizontal line going through the wing base center, and the line going to the wing tip
camber : the angle, looking from the top, of the wing going generaly to the rear (you have delta shape so it shall be a big number)
stall : if I remember that's for the air brake
flap : self explanatory (you can have more than one)
and the all the <control-input to define the diferent flaps and ails
control speed : set the time the flap need to go from 0 to 1

<vstab : to define a vertical stab (half one only, the FDM will calculate the oposit one)
So, in your case, you don't have one but you need to define a virtual one to steer your plane

<hstab : to define horizontal stab and rudder
same remark for a virtual one

<propeler : guess what...... to define the propellers (only one in your case)

<gear : one for each wheel
x, y, z being the contact point with the ground

you will have to put one line <vstab for each gear arm between the wheel and the body

<tank : x, y, z for its location, capacity for its ...... capacity (in lbs if I remember)

you can add ballasts to tune the plane stability

so with these, you will have a basic FDM to start with.

I'll come back to you later this week after check in my archives for Bukaro's tutorial

enjoy.........


Pourquoi cet avatar : il a réussi à les arrêter LUI au moins.......
Amicalement, Didier, Poitiers 86; LFBI alt 129m, 46°35'22.9"N 0°18'32.7"E
"Ils ne savaient pas que c'était impossible, alors ils l'on fait" Marc Twain

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#3 2015-03-23 17:03:18

D-ECHO
Créateur
Inscription : 2014-10-28
Messages : 125

Re : EchoAir Xperience

Didier1963 a écrit :

Do you know how to take coordinate of an object with Blender?

No, I dont. Can you tell me it? (Or is it in your text and I just didnt find it?)

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#4 2015-03-23 18:02:56

Didier1963
Developpeur
Lieu : Poitiers
Inscription : 2012-10-24
Messages : 1 233

Re : EchoAir Xperience

It is not in the tuto so I will put it by the end of this week.


Pourquoi cet avatar : il a réussi à les arrêter LUI au moins.......
Amicalement, Didier, Poitiers 86; LFBI alt 129m, 46°35'22.9"N 0°18'32.7"E
"Ils ne savaient pas que c'était impossible, alors ils l'on fait" Marc Twain

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#5 2015-03-23 19:17:04

Didier1963
Developpeur
Lieu : Poitiers
Inscription : 2012-10-24
Messages : 1 233

Re : EchoAir Xperience

Wile looking in my files about FDM, I found this adress

http://www.buckarooshangar.com/flightge … faces.html

Go and have look, it is really well made and verry interesting if you want to work on FDM's.

You have all the explanation I was trying to tell you from my memory (I can see that I forgot some and mixt up others).

Enjoy...............


Pourquoi cet avatar : il a réussi à les arrêter LUI au moins.......
Amicalement, Didier, Poitiers 86; LFBI alt 129m, 46°35'22.9"N 0°18'32.7"E
"Ils ne savaient pas que c'était impossible, alors ils l'on fait" Marc Twain

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#6 2015-04-11 15:06:13

D-ECHO
Créateur
Inscription : 2014-10-28
Messages : 125

Re : EchoAir Xperience

Xperience4two

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