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FDM: minor changes on CG, lift due to ground effect, add variable pit…

…ch propeller for 160 hp fiting (#922)
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dany93 authored and onox committed May 4, 2017
1 parent 314f912 commit de8e48b7bcfd87d0e0592c893531c2ddcc3b4880
Showing with 76 additions and 6 deletions.
  1. +69 −0 Engines/prop_75in_2f_NACA_15-30deg.xml
  2. +7 −6 c172p.xml
@@ -0,0 +1,69 @@
<?xml version="1.0"?>

<!--
Diameter: 75 in (1.91 m)
Calculated blade angle: at 75% of the radius
Data from NACA Report 640 : http://naca.central.cranfield.ac.uk/reports/1938/naca-report-640.pdf
-->

<propeller name="variable-Pitch 75-inch Two-Blade Propeller">

<ixx> 1.67 </ixx>
<diameter unit="IN"> 75.0 </diameter>
<numblades> 2 </numblades>
<minpitch> 15 </minpitch>
<maxpitch> 30 </maxpitch>

<table name="C_THRUST" type="internal">
<tableData>
15 20 25 30
0 0.0990 0.1040 0.1125 0.1175
0.1 0.0950 0.1040 0.1100 0.1170
0.2 0.0880 0.1030 0.1075 0.1150
0.3 0.0780 0.1010 0.1060 0.1125
0.4 0.0645 0.0930 0.1055 0.1100
0.5 0.0495 0.0820 0.1045 0.1080
0.6 0.0340 0.0700 0.0970 0.1075
0.7 0.0185 0.0550 0.0870 0.1075
0.8 0.0040 0.0390 0.0750 0.1040
0.9 -0.0160 0.0240 0.0600 0.0950
1 -0.0300 0.0060 0.0450 0.0825
1.1 -0.0400 -0.0140 0.0300 0.0695
1.2 -0.0500 -0.0330 0.0150 0.0540
1.3 -0.0550 -0.0450 -0.0010 0.0380
1.4 -0.06 -0.0550 -0.0130 0.0225
1.5 -0.0650 -0.0600 -0.0250 0.0075
1.6 -0.0700 -0.0650 -0.0380 -0.0090
2 -0.0750 -0.0720 -0.0700 -0.0550
3 -0.0800 -0.0800 -0.0900 -0.1000

</tableData>
</table>

<table name="C_POWER" type="internal">
<tableData>
15 20 25 30
0 0.0400 0.0660 0.1080 0.1420
0.1 0.0406 0.0650 0.1060 0.1405
0.2 0.0406 0.0640 0.1020 0.1380
0.3 0.0400 0.0625 0.0975 0.1360
0.4 0.0366 0.0600 0.0910 0.1330
0.5 0.0318 0.0580 0.0860 0.1280
0.6 0.0250 0.0540 0.0825 0.1230
0.7 0.0160 0.0475 0.0790 0.1180
0.8 0.0050 0.0370 0.0730 0.1140
0.9 -0.0067 0.0260 0.0640 0.1080
1 -0.0150 0.0100 0.0520 0.1000
1.1 -0.0200 0.0000 0.0375 0.0895
1.2 -0.0250 -0.0100 0.0220 0.0750
1.3 -0.0270 -0.0200 0.0040 0.0580
1.4 -0.0285 -0.0278 -0.02 0.0380
1.5 -0.0300 -0.0350 -0.0400 0.0180
1.6 -0.0315 -0.0390 -0.0530 -0.0070
2 -0.0330 -0.0500 -0.0750 -0.0750
3 -0.0350 -0.0550 -0.1000 -0.1200

</tableData>
</table>

</propeller>
@@ -43,7 +43,7 @@

<!--
Cessna 172P Skyhawk 1982 (160hp) POH p.6-10, Weight and Moment:
**Basic Empty** (= with full oil) 1467 lbs, 57300 lb-ins. Gives CG at 39.1 ins.
**Basic Empty** (= with full oil) 1467 lbs, 57300 lb-ins. Gives CG at 39.06 ins.
-->
<mass_balance>
<ixx unit="SLUG*FT2"> 948 </ixx>
@@ -54,7 +54,7 @@
<iyz unit="SLUG*FT2"> -0 </iyz>
<emptywt unit="LBS"> 1467 </emptywt>
<location name="CG" unit="IN">
<x> 39.1 </x>
<x> 39.06 </x>
<y> 0 </y>
<z> 36.5 </z>
</location>
@@ -188,11 +188,11 @@
</pointmass>

<!-- Extra weight for the aircraft with 180 hp engine, **Basic empty** (= with full oil), pointmass [15]; managed by Systems/bushkit.xml -->
<!-- for empty aircraft CG at x = 38.1 ins, cf. 172S - N552SP POH (1998) p.6-12, Weight and moment tabulation: 1642 lbs, 62600 lb-ins -->
<!-- for empty aircraft CG at x = 38.12 ins, from Cessna 172S - N552SP POH (1998) p.6-12, Weight and moment tabulation: 1642 lbs, 62600 lb-ins -->
<pointmass name="extra weight 180hp">
<weight unit="LBS"> 0 </weight>
<location name="POINTMASS" unit="IN">
<x> 30.3 </x>
<x> 30.29 </x>
<y> 0 </y>
<z> 26.6 </z>
</location>
@@ -575,6 +575,7 @@
</orient>
<feed>2</feed> <!-- from intermediate tank (float chamber 2) -->
<thruster file="prop_75in2f">
<!-- <thruster file="prop_75in_2f_NACA_15-30deg"> --> <!-- for settling -->
<location unit="IN">
<x> -37.7 </x>
<y> 0 </y>
@@ -602,8 +603,8 @@
<yaw> 0 </yaw>
</orient>
<feed>3</feed> <!-- from intermediate tank (float chamber 3) -->
<!-- <thruster file="prop_76in2f_NACA_15-25deg"> -->
<thruster file="prop_76in2f_NACA_20deg">
<!-- <thruster file="prop_76in2f_NACA_15-25deg"> --> <!-- for settling -->
<location unit="IN">
<x> -37.7 </x>
<y> 0 </y>
@@ -1055,7 +1056,7 @@
0.1500 1.0900
0.2000 1.0730
0.3000 1.0460
0.4000 1.0550
0.4000 1.0280
0.5000 1.0190
0.6000 1.0130
0.7000 1.0080

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