For 4x setup with HQ 50x43x3.
#!/usr/bin/env gnuplot set terminal png size 1600,1200 set output "eco-1900.png" set yrange [0:140] set xrange [0:7000] set ylabel "current, A" set xlabel "thrust, G" set ytics 5 set xtics 500 set grid xtics ytics $emax1700 << EOD 0.9 0 2.6 300 5.1 500 8.5 700 26.9 1580 EOD $emax1900 << EOD 1.1 0 2.9 300 5.3 500 8.7 700 34 1830 EOD $emax2400 << EOD 1.5 0 4.5 300 9.2 500 14.1 700 32.1 1370 EOD set arrow from 0,80 to 7000,80 nohead plot \ "$emax1700" using ($2*4):($1*4) with lines title "emax1700", \ "$emax1900" using ($2*4):($1*4) with lines title "emax1900", \ "$emax2400" using ($2*4):($1*4) with lines title "emax2400" pause -1