diff --git a/lib/node.ks b/lib/node.ks
index d721fd9..73f64b6 100644
--- a/lib/node.ks
+++ b/lib/node.ks
@@ -10,17 +10,20 @@ function estimated_burn_duration {
     // Based on:
     //  https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation
     //  https://space.stackexchange.com/questions/27375/how-do-i-calculate-a-rockets-burn-time-from-required-velocity
+    //  https://www.alternatewars.com/BBOW/Space/Rocket_Equations.htm
     //
     parameter burn.
     parameter isp is isp_sum().
-    parameter maxthrust is SHIP:maxthrust.
+    parameter thrust is SHIP:availablethrust.
 
     if burn:istype("Node") {
         set burn to burn:deltav.
     }
 
-    local exhaust_velocity is isp * (CONSTANT:G * KERBIN:mass).
-    return ((SHIP:mass * exhaust_velocity) / maxthrust) * (1 - CONSTANT:E^(-burn:mag/exhaust_velocity)).
+    local deltav is burn:mag.
+    local exhaust_velocity is isp * CONSTANT:g0.
+    local wet_mass is SHIP:mass.
+    return ((wet_mass * exhaust_velocity) / thrust) * (1 - CONSTANT:E^(-deltav/exhaust_velocity)).
 }