Second version

performanceCharts.m

@@ -1,24 +1,21 @@
 % Calculate the Lehner 2280-40 electric motor map from performance data
 % issued by the manufacturer. Plot propeller operating points on the map.
-% Version 1. Operating points manually chosen as close as possible to the
-% available manufacturer data.
+% Version 2. Current calculated from RPM and shaft power assigned by the
+% user, which has only to provide the desired propeller advance ratio J,
+% the expected shaft power in Watt and the RPM.
 close all; clearvars; clc
 
-% Avio engine scaled data
-% J	Voltage	Current	Input power	rpm     Momentum	Output power	Efficiency
-% - V       A       W           /min	Ncm         W               %
+% Operative points: J, Power (W), RPM
+MXCL = [1.46    403   9801
+        1.95    174   7351];
 
-MXCL = [1.46	48.9	11.4	557.5	8623	56.8	513     92
-        1.95	36.3	6.6     239.6	6470	32.4	219.4	91.6];
-MXCR = [1.84	39.1	9.8     383.2	6869	48.8	351.2	91.7
-        2.30	31.15	7.2     224.3	5495	35.6	205.1	91.4
-        2.76	25.8	5.2     134.2	4579	25.5	122.2	91.1
-        2.99	23.8	4.6     109.5	4232	22.5	99.5	90.9
-        3.22	22.1	4.4     97.2	3925	21.5	88.3	90.8];
+MXCR = [1.84	300   7807
+        2.30	159   6246
+        2.76	96    5205
+        2.99	77    4804
+        3.22	63    4461];
 
 % Lehner performance charts
-% Current	Input power     RPM     Momentum	Output power	Efficiency
-% A         W               /min	Ncm         W	            %
 V1 = csvread('data\V5.csv');
 V2 = csvread('data\V10.csv');
 V3 = csvread('data\V15.csv');
@@ -32,12 +29,14 @@
 V11 = csvread('data\V55.csv');
 V12 = csvread('data\V60.csv');
 
+% Current	Input power     RPM     Momentum	Output power	Efficiency
+% A         W               /min	Ncm         W	            %
 x = [V1(:,1); V2(:,1); V3(:,1); V4(:,1); V5(:,1); V6(:,1); V7(:,1); ...
-    V8(:,1); V9(:,1); V10(:,1); V11(:,1); V12(:,1)];
+    V8(:,1); V9(:,1); V10(:,1); V11(:,1); V12(:,1)]; % Current
 y = [V1(:,3); V2(:,3); V3(:,3); V4(:,3); V5(:,3); V6(:,3); V7(:,3); ...
-    V8(:,3); V9(:,3); V10(:,3); V11(:,3); V12(:,3)];
+    V8(:,3); V9(:,3); V10(:,3); V11(:,3); V12(:,3)]; % RPM
 z = [V1(:,5); V2(:,5); V3(:,5); V4(:,5); V5(:,5); V6(:,5); V7(:,5); ...
-    V8(:,5); V9(:,5); V10(:,5); V11(:,5); V12(:,5)];
+    V8(:,5); V9(:,5); V10(:,5); V11(:,5); V12(:,5)]; % Output power
 
 % Limit curves from data
 limCur = [V1(end,1); V2(end,1); V3(end,1); V4(end,1); V5(end,1); V6(end,1); V7(end,1); ...
@@ -50,7 +49,9 @@
 [xq, yq] = meshgrid(0:0.1:15, 0:10:11000);
 zq = griddata(x,y,z,xq,yq);
 
-% Purge data outside limits TODO?
+% Calculate current from expected output power and RPM (propeller data)
+MXCL(:,4) = griddata(z,y,x,MXCL(:,2),MXCL(:,3));
+MXCR(:,4) = griddata(z,y,x,MXCR(:,2),MXCR(:,3));
 
 %% Plot section
 figure(1)
@@ -69,8 +70,8 @@
 plot3(V11(:,1),V11(:,3),V11(:,5),'k--')
 plot3(V12(:,1),V12(:,3),V12(:,5),'k--')
 plot3(limCur,limRPM,limPow,'k-','LineWidth',2)
-climb = plot3(MXCL(:,3),MXCL(:,5),MXCL(:,7)+20,'or-','LineWidth',1.5);
-cruise = plot3(MXCR(:,3),MXCR(:,5),MXCR(:,7)+20,'oy-','LineWidth',1.5);
+climb = plot3(MXCL(:,4),MXCL(:,3),MXCL(:,2)+20,'or-','LineWidth',1.5);
+cruise = plot3(MXCR(:,4),MXCR(:,3),MXCR(:,2)+20,'oy-','LineWidth',1.5);
 hold off, grid on, view(-50,30) 
 xlabel('Current, A'), ylabel('RPM'), zlabel('Output power, W')
 legend([climb,cruise], 'MXCL', 'MXCR','Location','Best','Color','cyan')
@@ -90,13 +91,13 @@
 text(V12(end,1),V12(end,3),V12(end,5),'\leftarrow 60 V')
 
 for i = 1:size(MXCL,1)
-    text(MXCL(i,3),MXCL(i,5),MXCL(i,7)+20,...
+    text(MXCL(i,4),MXCL(i,3),MXCL(i,2)+20,...
         ['J = ',num2str(MXCL(i,1)), ' \rightarrow'], ...
         'HorizontalAlignment','right')
 end
 
 for i = 1:size(MXCR,1)
-    text(MXCR(i,3),MXCR(i,5),MXCR(i,7)+20,...
+    text(MXCR(i,4),MXCR(i,3),MXCR(i,2)+20,...
         ['J = ',num2str(MXCR(i,1)), ' \rightarrow'], ...
         'HorizontalAlignment','right')
 end
@@ -118,8 +119,8 @@
 plot(V11(:,1),V11(:,3),'k--')
 plot(V12(:,1),V12(:,3),'k--')
 plot(limCur,limRPM,'k-','LineWidth',2)
-climb = plot(MXCL(:,3),MXCL(:,5),'or-','LineWidth',1.5);
-cruise = plot(MXCR(:,3),MXCR(:,5),'oy-','LineWidth',1.5);
+climb = plot(MXCL(:,4),MXCL(:,3),'or-','LineWidth',1.5);
+cruise = plot(MXCR(:,4),MXCR(:,3),'oy-','LineWidth',1.5);
 hold off
 clabel(C,H,'FontSize',15,'Color','white')
 xlabel('Current, A'), ylabel('RPM'), title('Output power contour, W')
@@ -140,13 +141,13 @@
 text(V12(end,1),V12(end,3),'\leftarrow 60 V')
 
 for i = 1:size(MXCL,1)
-    text(MXCL(i,3),MXCL(i,5),...
+    text(MXCL(i,4),MXCL(i,3),...
         ['J = ',num2str(MXCL(i,1)), ' \rightarrow'], ...
         'HorizontalAlignment','right')
 end
 
 for i = 1:size(MXCR,1)
-    text(MXCR(i,3),MXCR(i,5),...
+    text(MXCR(i,4),MXCR(i,3),...
         ['J = ',num2str(MXCR(i,1)), ' \rightarrow'], ...
         'HorizontalAlignment','right')
 end