Second attemt:
save this file as "WhatEverName.aircraft"
As said it's for the M20K, so you need to alter some of the values but can give you a quick start
Also double check the all relevant data according to your needs.
kindest regards,
<?xml version="1.0" encoding="utf-8"?>
<Aircraft Name="Mooney M20K-252" Registration="PH-XXX" FuelType="AvGas100LL" AlternateFuelType="None" FuelMeasurementType="Volume" FuelMeasurementVolumeType="Litres" FuelMeasurementMassType="Kilograms" TaxiFuel="6.000000" LandingFuel="1.000000" MaxFuel="286.000000" EmptyWeight="939.979468" EmptyArmLon="112.83" EmptyArmLat="0.00" Type="M20T" ColourMarkings="WHITE AND BLUE" ServiceCeiling="24000" Equipment1="DFGLOVY" Equipment2="S" OtherCommsEquipment="" OtherNavEquipment="" PbnEquipment="" FuelContingency="0.05" HoldingMinutes="45" HourlyCost="212" HourlyCostIncludesFuel="False" GlideAirspeed="85.00" GlideRatio="12.00" DefaultLevel="18000" Envelope="103.05,939.979468,103.05,1072.020207,110.20,1315.009640,125.20,1315.009640,125.20,939.979468">
<ClimbProfile FpmSL="800.000000" FpmSC="500.000000" IndicatedAirspeed="105.000000" FuelBurnSL="60.000000" FuelBurnSC="60.000000" />
<DescentProfile Fpm="-700.000000" IndicatedAirspeed="170.000000" FuelBurn="20.000000" />
<CruiseProfiles>
<CruiseProfile Name="65% - SL" FuelBurn="39.700000" IndicatedAirspeed="144.000000" Airspeed="144.000000" AirspeedType="True" />
<CruiseProfile Name="65% - FL040" FuelBurn="39.700000" IndicatedAirspeed="150.000000" Airspeed="150.000000" AirspeedType="True" />
<CruiseProfile Name="65% - FL080" FuelBurn="39.700000" IndicatedAirspeed="151.000000" Airspeed="151.000000" AirspeedType="True" />
<CruiseProfile Name="65% - FL120" FuelBurn="39.700000" IndicatedAirspeed="162.000000" Airspeed="162.000000" AirspeedType="True" />
<CruiseProfile Name="65% - FL160" FuelBurn="39.700000" IndicatedAirspeed="167.000000" Airspeed="167.000000" AirspeedType="True" />
<CruiseProfile Name="65% - FL180" FuelBurn="39.700000" IndicatedAirspeed="170.000000" Airspeed="170.000000" AirspeedType="True" />
<CruiseProfile Name="65% - FL200" FuelBurn="39.700000" IndicatedAirspeed="173.000000" Airspeed="173.000000" AirspeedType="True" />
<CruiseProfile Name="65% - FL240" FuelBurn="39.700000" IndicatedAirspeed="176.000000" Airspeed="176.000000" AirspeedType="True" />
</CruiseProfiles>
<LoadingPoints>
<FuelLoadingPoint Name="Fuel" LeverArm="123.39" LeverArmLat="0.00" DefaultValue="160.00" Capacity="286.00" />
<LoadingPoint Name="Pilot" LeverArm="89.62" LeverArmLat="0.00" DefaultValue="114.00" />
<LoadingPoint Name="Navigator" LeverArm="86.38" LeverArmLat="0.00" DefaultValue="63.00" />
<LoadingPoint Name="Rear Passenger" LeverArm="179.60" LeverArmLat="0.00" DefaultValue="0.00" />
<LoadingPoint Name="Baggage" LeverArm="242.60" LeverArmLat="0.00" DefaultValue="15.00" />
<LoadingPoint Name="Hat Rack" LeverArm="302.30" LeverArmLat="0.00" DefaultValue="5.00" />
</LoadingPoints>