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DHC-6 Twin Otter development

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Re: DHC-6 Twin Otter development

Postby Patten » Tue Nov 11, 2014 5:53 pm

Hi,
New cabin light, and a DME with tooltips, and textured like the others instruments.
Image
Image



Uploaded in my hangar:
http://pattenflightgear.wifeo.com/dhc6- ... -otter.php
Thanks to abassign and primtala2.
Patten
Last edited by Patten on Fri Nov 14, 2014 8:35 am, edited 1 time in total.
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Re: DHC-6 Twin Otter development

Postby legoboyvdlp » Wed Nov 12, 2014 1:13 am

Just got it :)
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Re: DHC-6 Twin Otter development

Postby primtala2 » Sun Nov 16, 2014 1:30 pm

Patten wrote in Tue Nov 11, 2014 5:53 pm:Hi,
New cabin light, and a DME with tooltips, and textured like the others instruments.
Image
Image



Uploaded in my hangar:
http://pattenflightgear.wifeo.com/dhc6- ... -otter.php
Thanks to abassign and primtala2.
Patten


That DME is a good add-on for the cockpit. However it only works with a waypoint loaded into the route manager via the menu. That's not very realistic in my opinion because that's just not the way a DME works. The dme should become active when you put VOR/DME frequency into your NAV1.
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Re: DHC-6 Twin Otter development

Postby lanbo64 » Tue Nov 25, 2014 6:58 am

Patten wrote in Tue Nov 11, 2014 5:53 pm:Hi,
New cabin light, and a DME with tooltips, and textured like the others instruments.
Image
Image



Uploaded in my hangar:
http://pattenflightgear.wifeo.com/dhc6- ... -otter.php
Thanks to abassign and primtala2.
Patten


Hello Patten,

I like your DHC6 very much, but there are some problems that I hope to let you know.

First. Where did you find any resource of the autothrottle subsystem in DHC6? If I am correct, some DHC6 have a Colins Autopilots system, but the "IAS" button is for pitch-for-speed mode, not for AT.

Second, the startup process is very unrealistic. I don't even need the master battery, everytime I push the conditionals up, the engines just start.

I know a little programming, but I don't know how to do the pitch-for-speed in FlightGear. Even the great B1900D model fails in this part, the IAS is useless. But I like to help if you need.

Sincerely
Bo
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Re: DHC-6 Twin Otter development

Postby Patten » Tue Nov 25, 2014 11:05 am

lanbo64 wrote in Tue Nov 25, 2014 6:58 am:I know a little programming, but I don't know how to do the pitch-for-speed in FlightGear. Even the great B1900D model fails in this part, the IAS is useless. But I like to help if you need.

Sincerely
Bo


Hello lanbo64,

Thanks, no problem, when you want...

Kind regards

Patten
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Re: DHC-6 Twin Otter development

Postby lanbo64 » Sat Dec 06, 2014 4:00 pm

Patten wrote in Tue Nov 25, 2014 11:05 am:Thanks, no problem, when you want...


Hi Patten and every FlightGear friends,

Thank you for your encouraging.

I have changed three things for this model:
1) The IAS AT system is changed to "speed-with-pitch" system. I have a similar question before on your French forum, and I know that every DHC-6 has different settings and system, but I am pretty sure that currently, almost no props plane has AT because of the properllering pitching is more complecated.

This is the related code:
Code: Select all
 <filter>
  <name>AP:Pitch sample and hold</name>
  <debug>false</debug>
  <enable>
   <condition>
     <property>controls/autopilot/settings/iasflag</property>
   </condition>
  </enable>
  <type>gain</type>
  <gain>10.0</gain>
  <input>instrumentation/airspeed-indicator/indicated-speed-kt</input>
  <reference>autopilot/settings/target-speed-kt</reference>
  <output>autopilot/internal/target-pitch-deg</output>
  <max>30</max>
  <min>-30</min>
 </filter>
 
    <pi-simple-controller>
        <name>flc</name>
        <debug>false</debug>
        <enable>
            <condition>
                <or>
                    <equals>
                      <property>/autopilot/locks/altitude</property>
                        <value>FLC</value>
                    </equals>
                    <equals>
                      <property>/autopilot/locks/altitude</property>
                        <value>VFLC</value>
                    </equals>
                </or>
            </condition>
        </enable>
        <input>
            <prop>orientation/pitch-deg</prop>
        </input>
   <reference>
     <prop>autopilot/internal/target-pitch-deg</prop>
   </reference>
        <output>
          <prop>controls/flight/elevator</prop>
        </output>
         <config>
      <Kp>-0.06</Kp>      <!-- proportional gain -->
      <beta>1.0</beta>    <!-- input value weighing factor -->
      <alpha>0.1</alpha>  <!-- low pass filter weighing factor -->
      <gamma>0.0</gamma>  <!-- input value weighing factor for -->
                          <!-- unfiltered derivative error -->
      <Ti>1.0</Ti>        <!-- integrator time -->
      <Td>0.00001</Td>    <!-- derivator time -->
      <u_min>-0.5</u_min>
      <u_max>0.5</u_max>
    </config>
    </pi-simple-controller>


2) The ALT holding is now based on indicated altitude (or pressure altitude), not on GPS position. The reason I change it is because, in the real world, if the ATC require us climb to a level, it means the pressure altitude, and every other aircraft should do the same thing to avoid collisions.

Related code is:
Code: Select all
<pi-simple-controller>
  <name>Altitude Hold (Altimeter based) Stage 1</name>
  <debug>false</debug>
  <enable>
    <prop>autopilot/locks/altitude</prop>
    <value>altitude-hold</value>
  </enable>
  <input>
    <prop>instrumentation/altimeter/indicated-altitude-ft</prop>
  </input>
  <reference>
    <prop>autopilot/settings/target-altitude-ft</prop>
  </reference>
  <output>
    <prop>autopilot/internal/target-climb-rate-fps</prop>
  </output>
  <config>
    <Kp>0.3</Kp>
    <Ki>0.0</Ki>
    <u_min>-33.3</u_min>
    <u_max>33.3</u_max>
  </config>
</pi-simple-controller>


3) The DME now works for VOR/DME frequency, but I would not delete the GPS waypoint feature, because in the future, we may have an onboard GPS system. (I hope so :D )

Here is the download link:
If you can use Google Drive, please click here:
https://drive.google.com/file/d/0B1TXYE8yc_ktbmZiVW1YVVNBUG8

If you like a direct link from my website, please click here (but may slow :shock: ):
http://wealthlibre.info/static/webup-2014-12-06-105536-dhc6-ias-dme-alt-20141206.tar.gz

Here is a super long video I record from VNKT to VNLK (Wow one of the most dangerous airport in the world). If you don't want to watch long video, at the beginning, you can see what I improve the IAS and DME.
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Re: DHC-6 Twin Otter development

Postby D-MKF1 » Sat Dec 06, 2014 10:23 pm

Can't say more than: Wow!!
Thank you very much for your work. You did a very good job.
And we can take it and fly for free.

Its great.
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Re: DHC-6 Twin Otter development

Postby primtala2 » Fri Dec 12, 2014 3:29 am

Nice improvements, lanbo64
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Re: DHC-6 Twin Otter development

Postby Michat » Fri Dec 12, 2014 6:16 am

Thanks for your efforts guys. Very appreciated. Congratulations.
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Re: DHC-6 Twin Otter development

Postby lanbo64 » Sun Dec 14, 2014 4:40 am

Hello,

This time, I tried to make a better engine startup process, boost pumps, and torque psi. Get it from here: https://drive.google.com/file/d/0B1TXYE8yc_ktVXlCc29ySERwTTQ/view

Here is a video about this update.


In this update, the engines will not start without following a right startup process:
1) Turn on the master battery. Turn on every lights if you need.
2) Switch power source to battery. (External Power are not implemented yet, sorry)
3) Turn on both boost pumps.
4) Press the starter.
5) After the ng (GG) higher than 12%, push the condition to forward.
6) The engine will light.
(If it does not light within 10 secs, cut the fuel off; keep the starter to spin the engine more than 10 secs to evacuate the unburned fuel.)
7) Repeat from "Step 4)" to start another engine.

Something important or you may fail to start:
1) Due to lack of External Power, please make sure you have more than 20 volts to start each engine, if not, restart your program lol. DHC6 is a very crazy plane which can fly to everywhere, so a well charged battery is definitely good to start each engine.
2) DO NOT push the condition before the starter. If you already did, follow the Step 6) above. lol.
3) In the real world, we have to use our left hand to press the stater, and then, use our right hand to push the condition, and then, we would release the starter. However, in computer, we do not have two mouses, so make use to toggle off the starter after engine lighting.
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Re: DHC-6 Twin Otter development

Postby Patten » Sun Dec 14, 2014 7:50 am

Good job, tanks.
Patten
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Re: DHC-6 Twin Otter development

Postby Johan G » Sun Dec 14, 2014 2:09 pm

Nice! :D
Low-level flying — It's all fun and games till someone looses an engine. (Paraphrased from a YouTube video)
Improving the Dassault Mirage F1 (Wiki, Forum, GitLab. Work in slow progress)
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Re: DHC-6 Twin Otter development

Postby abassign » Mon Dec 15, 2014 2:29 pm

It is really very nice, but the autostart now does not work :( Though certainly not realistic, but take the DHC6 and make a flight around the airport without having to wait to start the engines, sometime, is fantastic :) !
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Re: DHC-6 Twin Otter development

Postby lanbo64 » Mon Dec 15, 2014 3:07 pm

abassign wrote in Mon Dec 15, 2014 2:29 pm:It is really very nice, but the autostart now does not work :( Though certainly not realistic, but take the DHC6 and make a flight around the airport without having to wait to start the engines, sometime, is fantastic :) !


I am glad you like it. I am agree with you actually. It may be also better for quick testing. But the autostart script need to re-write, so it take sometime.
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Re: DHC-6 Twin Otter development

Postby lanbo64 » Wed Dec 17, 2014 6:49 pm

Okay, this time, I just bring the autostart back, so you can enjoy your quick flight or the convenience of development testing. Also, I polish the speed-with-pitch system, and it is smoother and safer now, and then, I fix a little glitch of the HDG heading bug -- now, it is based on heading indicator but not mag north.

Get it from my google drive... https://drive.google.com/file/d/0B1TXYE8yc_ktTkYteW8zTkR2S2s/view?usp=sharing
Last edited by lanbo64 on Thu Dec 18, 2014 6:57 am, edited 2 times in total.
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