SE 212 Durandal

SE 212 Durandal. In progress 

9 Nov 2023

The SE 212 Durandel is a simple deal winged jet fighter prototype, smaller than the Mirage III, and originally using a jet and a rocket engine. It first flew in the 1950s, but was unable to achieve high supersonic speeds and was eventually abandoned.

The model here is based on the Zagi flying wing model, so some changes have to be made, especially the moments of inertia in pitch and roll, which may need to be switched.  

The Zagi configuration file is as follows, in part:

 <aero version="1" units="0">

    <ref chord="0.833333" span="4" area="3.33333" speed="19.685" />

Reference chord and span, area all in feet adn sq ft.   Converting:  Ref chord = 0.254m,  span =  1.22 metres and Area is 0.3716 sq. m

The Durandal model, 1:10 scale, will have a chord of , span of, and wing area of.

Reverse converting:

    <misc Alpha_0="0" eta_loc="0.25" CG_arm="0.25" span_eff="0.85" />

    <m Cm_0="0.0100395" Cm_a="-0.42268" Cm_q="-1.68929" Cm_de="-0.210653" />

    <lift CL_0="0.132896" CL_max="1.1" CL_min="-0.8" CL_a="4.08115" CL_q="4.90714"

       CL_de="0.49144" CL_drop="0.1" CL_CD0="0.3" />

    <drag CD_prof="0.025" Uexp_CD="-0.5" CD_stall="0" CD_CLsq="0.02" CD_AIsq="0.04"

       CD_ELsq="0.04" />

CD_prof may need changing


    <Y CY_b="-0.10799" CY_p="-0.03859" CY_r="0.0595832" CY_dr="0" CY_da="0.02049" />

    <l Cl_b="-0.05249" Cl_p="-0.42547" Cl_r="0.04428" Cl_dr="0" Cl_da="0.13327" />

    <n Cn_b="0.0213716" Cn_p="-0.000882313" Cn_r="-0.0122373" Cn_dr="0"

       Cn_da="-0.00725753" />

  </aero>

The moments of inertia and the motor files are as follows:

<mass_inertia version="1" units="0" Mass="0.0475927" I_xx="0.0208188"

0.0475927 Slug = 694.563244 Gram.  The Zagi weighs 700 g approx.  Compare this to a similar sized Mirage model and 

we can work out how accurate this is.    I_YY appears to be pitch moment of inertia.


       I_yy="0.00449063" I_zz="0.0252959" I_xz="0" />

    <sound version="1">

      <sample filename="electric.wav" type="1" pitchfactor="0.007" maxvolume="1" />

    </sound>

Power units: I plan to use the battery model of the Flexifly with a NiMh or LiPo battery, these batteries run down in the simulator,  the default battery has unlimited duration.

    <power units="1">

      <automagic F="2.668932" V="12.501971">

        <battery throttle_min="0">

          <automagic T="420" />

          <shaft J="0" brake="1">

            <propeller D="0.24384" H="0.170688" J="0" n_fold="5" />

            <engine>

              <automagic omega_p="2827" eta_opt="0.78" eta="0.7" />

            </engine>

          </shaft>

        </battery>

      </automagic>

    </power>

  </config>


Flexifly XLM


<power units="1">

        <battery filename="nimh7_kan1050" throttle_min="0">

          <shaft J="0" brake="1">

            <propeller D="0.15" H="0.075" J="0" n_fold="5" >

              <pos x="0.09" downthrust="6" />

            </propeller>

            <engine filename="Mabuchi_380_FR" />

          </shaft>

        </battery>

    </power>

Battery config file is below. If you change battery to   C="0.0300" then the motor switches off in about 10 seconds. This is a good way

of making realistic battery limits.  C="0.100" results in 2 minutes power 


<battery C="0.300" U_0="10.5" U_off="5.5" R_I="9E-3">

     <U_0rel>

       1.00;

       0.93;

.

  ...

     </U_0rel>

   </battery>

Partially completed Durandal model

The Zagi model that the Durandal is based on, an electric model.