Beagle Pup experiment

Everything in connection with developing aircraft for FlightGear
User avatar
IAHM-COL
Posts: 6455
Joined: Sat Sep 12, 2015 3:43 pm
Location: Homey, NV (KXTA) - U.S.A
Contact:

Re: Beagle Pup experiment

Postby IAHM-COL » Wed Nov 16, 2016 9:35 pm

Also the pup is tricycle
https://raw.githubusercontent.com/IAHM-COL/gpg-pubkey/master/pubkey.asc

R.M.S.
If we gave everybody in the World free software today, but we failed to teach them about the four freedoms, five years from now, would they still have it?

sanhozay
Posts: 167
Joined: Fri Sep 25, 2015 5:59 pm

Re: Beagle Pup experiment

Postby sanhozay » Wed Nov 16, 2016 10:00 pm

IAHM-COL wrote:where does that number go?

https://github.com/FGMEMBERS-NONGPL/Bea ... -Model.xml

Line 927.

Richard
Posts: 114
Joined: Sun Sep 11, 2016 5:57 pm

Re: Beagle Pup experiment

Postby Richard » Wed Nov 16, 2016 10:16 pm

Based on feedback from Wayne and Vincent I've been tuning the inertias and also the CoG and control surface moments - this is to see if I can get a model that we think flies correctly and then figure out if it's right or not.

The moments of inertia that VSPAERO calculates should be more accurate; except that I don't understand what it is doing which makes it difficult. More research for me in this area. Also the control surface moments could well be wrong based on how VSPAERO calculates them (by deflecting the normals on the affected segments of the degenerate geometry).

Revised FDM is here if anyone's got time to test it. http://chateau-logic.com/sites/default/ ... -11-16.zip - this is just the FDM XML to put into Beagle-Pup/

KL-666
Posts: 1610
Joined: Mon Sep 28, 2015 8:42 am

Re: Beagle Pup experiment

Postby KL-666 » Thu Nov 17, 2016 12:19 am

Hi Richard,

What i make of the changes is that the initiating of the movement has become heavy too now. But otherwise the issue is still there. For quick testing while you develop you can just test take off rotation. A good symptom of the problem is that at the end of rotation you have to push instead of just put the stick neutral for a constant climb. When you get that right, i think the major part is solved. Btw, it is not a trim problem, i need this trim to rotate at all.

On glide slope i noticed that i needed much (at least halfway) trim up in a desc of 300 ft/min below 80 kts. Other planes do not need that (more neutral trim). Maybe your whole hstab needs to be in more trim up position, or your CG is too far forward.

Kind regards, Vincent

User avatar
IAHM-COL
Posts: 6455
Joined: Sat Sep 12, 2015 3:43 pm
Location: Homey, NV (KXTA) - U.S.A
Contact:

Re: Beagle Pup experiment

Postby IAHM-COL » Thu Nov 17, 2016 4:09 am

@bomber, and @Sanhozay

I used Sanhozay's suggested 12.5 value.
Now I feel taxiing to be more doable.

New VIDEO
AVALAIBLE NOW

@Bomber,
I think with your updates on the bogeys the spring improved a lot, and with the increased steering, the plane gain a lot of maneuverability in ground.
I am initiating a pull request to merge this changes into your FDM. Let me know if you approve of it, and I'll merge into.

https://github.com/FGMEMBERS-NONGPL/Bea ... ll/1/files
IH-COL
https://raw.githubusercontent.com/IAHM-COL/gpg-pubkey/master/pubkey.asc

R.M.S.
If we gave everybody in the World free software today, but we failed to teach them about the four freedoms, five years from now, would they still have it?

bomber
Posts: 1379
Joined: Mon Nov 30, 2015 3:40 pm

Re: Beagle Pup experiment

Postby bomber » Thu Nov 17, 2016 11:29 am

I'm looking at the friction co-efficients at the moment...

One of things I've noticed is that the brakes are either full on or off, which makes for an exaggerated bounce, how about I do some out of the box coding allowing the pilot to apply variable brake pressure using the stick.
"If anyone ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me - it's all balls" - R J Mitchell

Richard
Posts: 114
Joined: Sun Sep 11, 2016 5:57 pm

Re: Beagle Pup experiment

Postby Richard » Thu Nov 17, 2016 12:18 pm

it's best to do this in the joystick input file;

I had something similar for independent engine control by using a button to define whether the one throttle axis was left,right or both. I can see no reason why this technique couldn't be used to control the amount of braking - with either the normal keys or another two buttons on the joystick to apply the brakes.

something like this;

Code: Select all

  <axis n="2">
    <desc type="string">Throttle2</desc>
      <binding>
          <command>property-scale</command>
          <property>/controls/engines/throttle-dmd</property>
          <offset type="double">-1.0</offset>
          <factor type="double">-0.5</factor>
      </binding>
      <binding>
          <command type="string">nasal</command>
          <script type="string">
              <![CDATA[
              #
              # this uses the two buttons on the joystick (next to the throttle control)
              # to allow independent control of the engines. The lower button toggles the left engine
              # and the upper the right engine
                    if (getprop("/controls/engines/engine[0]/active") == nil)
                        setprop("/controls/engines/engine[0]/active",1);
                    if (getprop("/controls/engines/engine[1]/active") == nil)
                        setprop("/controls/engines/engine[1]/active",1);

                    if (getprop("/controls/engines/engine[0]/active"))
                    setprop("/controls/engines/engine[0]/throttle", getprop("/controls/engines/throttle-dmd"));
                    if (getprop("/controls/engines/engine[1]/active"))
                    setprop("/controls/engines/engine[1]/throttle", getprop("/controls/engines/throttle-dmd"));
]]>
          </script>
          <module type="string">__js0</module>
      </binding>
  </axis>

    <button n="10">
        <desc type="string">LeftThrottle</desc>
        <repeatable type="string">false</repeatable>
        <binding>
            <command>property-toggle</command>
            <property>/controls/engines/engine[0]/active</property>
        </binding>
        <binding>
            <command type="string">nasal</command>
            <script type="string">
                <![CDATA[
                    if (getprop("/controls/engines/engine[0]/active"))
{
#setprop("/controls/engines/engine[0]/throttle", getprop("/controls/engines/throttle-dmd"));
                    gui.popupTip("Left Engine Control Active");
}
else
                    gui.popupTip("Left Engine Control Inactive");
                    if (getprop("/controls/engines/engine[1]/active"))
                    setprop("/controls/engines/engine[1]/throttle", getprop("/controls/engines/throttle-dmd"));
]]>
            </script>
            <module type="string">__js0</module>
        </binding>
    </button>
    <button n="11">
        <desc type="string">RightThrottle</desc>
        <repeatable type="string">false</repeatable>
        <binding>
            <command>property-toggle</command>
            <property>/controls/engines/engine[1]/active</property>
        </binding>
        <binding>
            <command type="string">nasal</command>
            <script type="string">
                <![CDATA[
                    if (getprop("/controls/engines/engine[0]/active"))
setprop("/controls/engines/engine[0]/throttle", getprop("/controls/engines/throttle-dmd"));

if (getprop("/controls/engines/engine[1]/active"))
{
#setprop("/controls/engines/engine[1]/throttle", getprop("/controls/engines/throttle-dmd"));
                    gui.popupTip("Right Engine Control Active");
}
else
                    gui.popupTip("Right Engine Control Inactive");
]]>
            </script>
            <module type="string">__js0</module>
        </binding>
    </button>

bomber
Posts: 1379
Joined: Mon Nov 30, 2015 3:40 pm

Re: Beagle Pup experiment

Postby bomber » Thu Nov 17, 2016 2:27 pm

JSBsim's brakes have been interrupted (if that's the correct word) by some nasal... which will add a complexity to anything I come up with to make it usable in both flightgear and Outerra.

and I'm not actually after another button in which to press but instead a means by which we can apply the brakes in a gradual manner, rather than the on or off two state method we have at present.
"If anyone ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me - it's all balls" - R J Mitchell

Richard
Posts: 114
Joined: Sun Sep 11, 2016 5:57 pm

Re: Beagle Pup experiment

Postby Richard » Thu Nov 17, 2016 3:30 pm

As long as you realise that the on or off is because of the input system in FlightGear and nothing specifically to do with JSBSim.

Therefore the correct multiplatform solution is to appropriately bind the brakes to a variably controllable input. If this isn't possible then a JSBSim system that can optionally be used is the best compromise; but it is really a controls / input problem not a FDM problem.

User avatar
IAHM-COL
Posts: 6455
Joined: Sat Sep 12, 2015 3:43 pm
Location: Homey, NV (KXTA) - U.S.A
Contact:

Re: Beagle Pup experiment

Postby IAHM-COL » Thu Nov 17, 2016 3:35 pm

oh! Gimme a break!
https://raw.githubusercontent.com/IAHM-COL/gpg-pubkey/master/pubkey.asc

R.M.S.
If we gave everybody in the World free software today, but we failed to teach them about the four freedoms, five years from now, would they still have it?


Return to “Aircraft Development”

Who is online

Users browsing this forum: No registered users and 27 guests