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McDonnell Douglas 902 Explorer [New release]

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McDonnell Douglas 902 Explorer [New release]

Postby Martien van der P. » Tue Mar 26, 2013 6:08 pm

Hi everybody,

Here is a new release from the MD-902. The model is made by Marco F (mandun). And Heiko Schulz helped with the FDM for the new release.The MD-902 is licenced under the GPL 2 license. The first flight of this heli in the real world was on 1992.
The Explorer was the first helicopter from McDonnell. It has the role as a light twin helicopter.
And is used as a police and air ambulance.
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MD 902 at EH01
Image
The cockpit from the MD 902
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Image

:!: :!: Download the MD 902 HERE :!: :!:
Last edited by Martien van der P. on Sat Jun 13, 2015 8:21 pm, edited 2 times in total.
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Re: McDonnell Douglas 900 Explorer

Postby Maerchenprinz » Thu Mar 28, 2013 5:42 pm

Hi!

Well done! I made a little flight with it yesternight; It looks really good, and even flies quite well. Did you copy an existing FDM or did you write one from scratch?
btw: An error in the console says: Failed to load file: "Aircraft/MD-900/Models/TailRotor/tailrotor.xml" :D
The tailrotor ITSELF is missing!

Ciao,

Adrian
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Re: McDonnell Douglas 900 Explorer

Postby VicMar » Fri Mar 29, 2013 12:57 pm

@ Maerchenprinz ,
This heli doesn't have a tail rotor. It uses a movable jet to steer.

I can't work out how to get it to start up. Any help appreciated.

Cheers,
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Re: McDonnell Douglas 900 Explorer

Postby helijah » Fri Mar 29, 2013 2:04 pm

hi

Oh great. Here is a vehicle that I can remove my todolist :)

Regards Emmanuel
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Re: McDonnell Douglas 900 Explorer

Postby Hooray » Fri Mar 29, 2013 2:17 pm

given that it's GPL2'ed, someone should fix the main issues and commit it to the repository, so that the model won't be getting lost.
Please don't send support requests by PM, instead post your questions on the forum so that all users can contribute and benefit
Thanks & all the best,
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Re: McDonnell Douglas 900 Explorer

Postby VicMar » Fri Mar 29, 2013 3:35 pm

Could someone PLEASE tell me how to start the engines.

Cheers,
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Re: McDonnell Douglas 900 Explorer

Postby Martien van der P. » Fri Mar 29, 2013 4:07 pm

There will be a development from the MD-900 (I get help from Heiko Schulz, he made the EC135).
And a new FDM to let it work better, this MD-900 is experimental.
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Re: McDonnell Douglas 900 Explorer

Postby Johan G » Fri Mar 29, 2013 4:22 pm

It might be a good idea to commit it anyway. Several people here have in the past lost their work due to computer crashes.

I hope you at least have recent copies spread across among its developers. :wink:
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Re: McDonnell Douglas 900 Explorer

Postby Martien van der P. » Fri Mar 29, 2013 4:39 pm

I've the model on a USB. That would be safe. :wink:
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Re: McDonnell Douglas 900 Explorer

Postby VicMar » Fri Mar 29, 2013 4:55 pm

Hi Martien,

One very obvious error:

The Explorer has a 5 blade main rotor.

Maverickalex did some work on this a while back, but I don't know how far he got. I think he was using the British police markings (Navy & Yellow) and was going to include the camera and searchlight pods.

I haven't seen any sign of Alex for a while, but he may still be contactable. EDIT: I attempted to make the 902 version, but stopped when Alex said it was a WIP. I did start on a 5 blade rotor in SketchUp if that is any use to you. Let me now.

Cheers,
Vic
Last edited by VicMar on Fri Mar 29, 2013 5:07 pm, edited 2 times in total.
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Re: McDonnell Douglas 900 Explorer

Postby Martien van der P. » Fri Mar 29, 2013 5:01 pm

I know he has a 5 blade rotor but it is still experimental. :) :D :lol:
EDIT: Maybe I need it
Last edited by Martien van der P. on Fri Mar 29, 2013 9:26 pm, edited 1 time in total.
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Re: McDonnell Douglas 900 Explorer

Postby Groucho » Fri Mar 29, 2013 9:09 pm

VicMar wrote in Fri Mar 29, 2013 12:57 pm:@ Maerchenprinz ,
This heli doesn't have a tail rotor. It uses a movable jet to steer.


To be precise the NOTAR works by letting out a low pressure air flow at the start of the tail boom at the starboard side. This leads to an aerodynamic effect in which the downwash from the main rotor is forced to flow around the tail boom in a leftward movement thus producing an anti - torque effect.
The outlet at the end of the tail is to support the yaw control. It would not be sufficient as replacement for the tail rotor alone hence the sophisticated approach with the main rotor downwash.
A very interesting concept indeed.
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Re: McDonnell Douglas 900 Explorer

Postby Raptor » Sat Mar 30, 2013 5:28 am

Nice Helicopter, i think this is the first helicopter with NOTAR system in FG, it looks like you are using FDM of SA-315B-Lama helicopter and it is having tail rotor.
So i did a small experiment by disabling tail rotor & adding 2 thruster's on tail end, but its not exactly like working of NOTAR system that is using pressure difference to producing an anti - torque effect.

below is my FDM with disabled tail rotor, now its easy to hover
Code: Select all
<?xml version="1.0" encoding="UTF-8"?>

<airplane mass="2085">

<approach speed="47" aoa="14">
  <control-setting axis="/controls/engines/engine[0]/throttle" value="0.3"/>
</approach>

<cruise speed="108" alt="0">
  <control-setting axis="/controls/engines/engine[0]/throttle" value="0.75"/>
</cruise>

  <rotor name="main"
         x="0.00" y="0.00" z="1.197"
         nx="0.011" ny="0" nz="1."
         fx="1" fy="0" fz="0"
         ccw="0"
         mincollective="-0.75" maxcollective="11.75"
         mincyclicele="-6" maxcyclicele="5.75"
         mincyclicail="-4.0" maxcyclicail="4.0"
         diameter="11.02"
         numblades="3"
         weightperblade="69"
         twist="-3.5"
         chord="0.334"
         rpm="385"
         relbladecenter="0.61"
         dynamic="0.9"
         rellenflaphinge="0.104"
         delta3="0.0" delta=".130"
         pitch-a="10" pitch-b="15"
         flapmin="-13" flapmax="13"
         flap0="-7.5" flap0factor="0" phi0="45"
         notorque="0"
         dragfactor="0.028"
         translift-ve="18"
      translift-maxfactor="1.31"
         ground-effect-constant="0.14"
      taper="1"
         number-of-segments="10"
         number-of-parts="10"
         rel-len-where-incidence-is-measured="0.5"
         rel-len-blade-start="0.16"
   
     airfoil-lift-coefficient="6.9"
       airfoil-drag-coefficient0="0.0078"
       airfoil-drag-coefficient1="0.10"
       incidence-stall-zero-speed="18"
       incidence-stall-half-sonic-speed="12"
       lift-factor-stall="0.18"
       drag-factor-stall="4.0"
       stall-change-over="5.5"
       cyclic-factor="1.0"
       rotor-correction-factor="0.89"
       downwashfactor ="0.21"
        >
<control-input axis="/controls/flight/aileron-trim" control="CYCLICAIL"/>
  <control-input axis="/controls/flight/fcs/roll" control="CYCLICAIL"
                  src0="-1.0" src1="1.0"
                  dst0="-1.0" dst1="1.0"/>
  <control-input axis="/controls/flight/elevator-trim" control="CYCLICELE"/>
  <control-input axis="/controls/flight/fcs/pitch" control="CYCLICELE"
                  src0="-1.0" src1="1.0"
                  dst0="-1.0" dst1="1.0"/>
<control-input axis="/controls/engines/engine[0]/throttle" control="COLLECTIVE"
                  src0="0.0" src1="1.0"
                                           dst0="1.0" dst1="-1"/>
</rotor>



<!-- #######

  <rotor name="tail"
         x="-6.175" y="-0.208" z="0.807"
         nx="0.00" ny="-1" nz="0.26"
         fx="1" fy="0" fz="0"
         ccw="0"
         mincollective="-18.0" maxcollective="12"
         diameter="1.91"
         numblades="3"
         chord="0.259"
         weightperblade="5"
         relbladecenter="0.7"
         dynamic="1"
         rpm="2052"
         rellenflaphinge="0.043"
         delta3="1"
         translift="0"
         delta="0.5"
         pitch-a="10" pitch-b="15"
   
         airfoil-lift-coefficient="5.3"
    airfoil-drag-coefficient0="0.0070"
    airfoil-drag-coefficient1="0.010"
         incidence-stall-zero-speed="18"
    incidence-stall-half-sonic-speed="9"
         lift-factor-stall="0.18"
         stall-change-over="5.5"
         drag-factor-stall="8.0"
         notorque="0"
         taper="1"
         number-of-segments="5"
         number-of-parts="4"
         rel-len-blade-start="0.1"
         downwashfactor="0.1"
         rotor-correction-factor="0.97"
        >
   
   <control-input axis="/controls/flight/fcs/yaw" control="COLLECTIVE" invert="true"
                  src0="-1.0" src1="1.0"
                  dst0="-1.0" dst1="1.0"/>
      <control-input axis="/controls/flight/fcs/tail-rotor/throttle" control="COLLECTIVE"
                  src0="0.0" src1="1.0"
                  dst0=".00000000000000000065" dst1=".00000000000000000065"/>
</rotor>
     ###### -->

  <!-- only the engine power below is a known good value -->
  <rotorgear max-power-engine="560"
             max-power-rotor-brake="100"
             rotorgear-friction="1.07"
             engine-prop-factor="0.01"
             engine-accel-limit="4"
             yasimdragfactor="30"
             yasimliftfactor="120">

<control-input axis="/controls/engines/engine[0]/magnetos" control="ROTORGEARENGINEON"/>
<control-input axis="/controls/rotor/brake" control="ROTORBRAKE"
                  src0="0.0" src1="1.0"
                  dst0="0.0" dst1="1.0"/>
  <control-input axis="/controls/rotor/reltarget" control="ROTORRELTARGET"
                 src0="0.0" src1="2.0"
                 dst0="0.0" dst1="2.0"/>
  <control-input axis="/controls/rotor/maxreltorque" control="ROTORENGINEMAXRELTORQUE"
                 src0="0.0" src1="2.0"
                 dst0="0.0" dst1="2.0"/>
</rotorgear>

<!-- Thrusters for Yaw  thrust="800" i think the thrust is too much, but its easy to hover  -->

<thruster x="-6.175" y="-0.208" z="0.807" vx="0" vy="1" vz="0" thrust="800">
      <control-input axis="/controls/flight/rudder" control="THROTTLE"
           src0="0" src1="1" dst0="0" dst1="1"/>
     <control-input axis="/orientation/yaw-rate-degps" control="THROTTLE"
           src0="-5" src1="0" dst0="0.3" dst1="0"/> 
</thruster>

<thruster x="-6.175" y="-0.208" z="0.807" vx="0" vy="-1" vz="0" thrust="800">
      <control-input axis="/controls/flight/rudder" control="THROTTLE"
           src0="-1" src1="0" dst0="1" dst1="0"/>
    <control-input axis="/orientation/yaw-rate-degps" control="THROTTLE"
           src0="0" src1="5" dst0="0" dst1="0.3"/>   
</thruster>   
<!-- ######  #### -->

  <cockpit x="1.709" y="0.00" z="0.252"/>

  <!-- Fuse -->
  <fuselage ax="2.708" ay="0" az="-0.067"
  bx="0.383" by="0" bz="-0.682"
  width="2.12" taper="0.48"
  midpoint="1.2"/>
 
  <fuselage ax="-0.303" ay="0" az="-0.628"
  bx="-6.897" by="0" bz="0.208"
  width="0.03" taper="1"
  midpoint="-3.45"
  cz="0.015"
  idrag="0.18"/>
 
 
   <fuselage ax="-0.66" ay="-0.754" az="-.628"
  bx="-6.207" by="-0.12" bz="0.82"
  width="0.3" taper="1"
  midpoint="-3.45"
  cz="0.015"
  idrag="0.18"/>
 
   <fuselage ax="-0.66" ay="0.754" az="-0.528"
  bx="-6.207" by="0.12" bz="0.82"
  width="0.3" taper="1"
  midpoint="-3.45"
  cz="0.015"
  idrag="0.18"/>
 
  <!-- fuel tank -->
  <fuselage ax="-0.257" ay="0" az="0.5"
  bx="-0.257" by="0" bz="-0.387"
  width="1.09" taper="0.13"
  midpoint="0" cx="0.5"
  cz="0.005"
  idrag="0.09"/>
 
 

  <vstab x="-7.091" y="0" z="0.352"
         chord="0.08"
         length="0.93"
         taper="1"
         effectiveness="0.001"
         sweep="0"
         incidence="-2">
         <stall aoa="26" width="4" peak="1.5"/>
  </vstab>

  <hstab x="-5.091" y="0.0" z="0.614"
         chord="0.302"
         length="1.92"
         taper="1.0"
         effectiveness="0.85"
         sweep="0"
         incidence="-1.5">
         <stall aoa="-26" width="1" peak="1.5"/>
  </hstab>

   <weight x="1.056" y="-0.87" z="-0.045" mass-prop="/sim/weight[0]/weight-lb"/>
   <!-- pilot -->
   <weight x="1.056" y="0.87" z="-0.045" mass-prop="/sim/weight[1]/weight-lb"/>
   <!-- co-pilot -->
   <weight x="0.269" y="0.43" z="-0.005" mass-prop="/sim/weight[2]/weight-lb"/>
   <!-- right passenger -->
   <weight x="0.269" y=".0" z="-0.005" mass-prop="/sim/weight[3]/weight-lb"/>
   <!-- middle passenger -->
   <weight x="0.269" y="-0.43" z="-0.005" mass-prop="/sim/weight[4]/weight-lb"/>
   <!-- left passenger -->
   <weight x="-0.046" y="0" z="-0.613" mass-prop="/sim/weight[5]/weight-lb"/>
   <!-- cargo hook -->

<!-- left skid -->
<gear x="1.528" y="+1.22" z="-1.160" skid="1" compression="0.030" spring="0.8" sfric="0.5" dfric="0.4"/>
<gear x="-0.745" y="+1.22" z="-1.160" skid="1" compression="0.030" spring="0.8" sfric="0.5" dfric="0.4"/>

<!-- right skid -->
<gear x="1.528" y="-1.22" z="-1.160" skid="1" compression="0.030" spring="0.8" sfric="0.5" dfric="0.4"/>
<gear x="-0.745" y="-1.22" z="-1.160" skid="1" compression="0.030" spring="0.8" sfric="0.5" dfric="0.4"/>

  <!-- Tail skid-->
  <gear x="-6.18" y="0" z="-0.39"
        skid="1"
        compression="0.01"
        spring="0.1"
        sfric="1"
        dfric="1">
  </gear>
 

   <tank x="-0.207" y="0.00" z="0.285" capacity="475"/>
    <tank x="-0.207" y="0.00" z="0.285" capacity="475"/>

  <!-- ballast-->

  <ballast x="-1.17" y="+0.0" z=" -1.16" mass="470"/>

 
  <ballast x="1.95" y="0.023" z=" 0.16" mass="100"/>
 

  <ballast x="-6.013" y="+0.0" z=" 0.79" mass="20"/>
 
   
 

</airplane>


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Re: McDonnell Douglas 900 Explorer

Postby Groucho » Sat Mar 30, 2013 10:23 am

Raptor wrote in Sat Mar 30, 2013 5:28 am:So i did a small experiment by disabling tail rotor & adding 2 thruster's on tail end, but its not exactly like working of NOTAR system that is using pressure difference to producing an anti - torque effect.


In fact the concept has some implications on the FDM. Using parts of the main rotor downwash will lead in a reduced lift of the backward running blade. As the MD900 has a counter-clockwise turning rotor the lack of blade lift will (caused by the approx. 90° phase shift of the blade effect) cause the helicopter to bank to the right. So any pitch change will show this effect more or less. I have no idea if the helicopter onboard system compensates this by eg. applying more cyclic input to the rear blade.

A positive effect: More pitch usually means more torque moment on conventional helicopters. As the NOTAR relies on the rotor downwash more pitch also means more air flow around the tail boom meaning more anti-torque effect here automatically. So the necessary compensation force is less.
In reality the dependent effects are a bit more complicated but we can leave it this way as this is the primary implication for the FDM.
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Re: McDonnell Douglas 900 Explorer

Postby Maerchenprinz » Fri Apr 05, 2013 10:01 pm

VicMar wrote in Fri Mar 29, 2013 12:57 pm:@ Maerchenprinz ,
This heli doesn't have a tail rotor. It uses a movable jet to steer.


Thanks for underestimating me that much, Vic... That's very un-eco and affective! :?: :!: :P

Cheers,

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