various tweaks

Parts/HeliumTankRadial/heliumTankRadial.cfg

@@ -8,7 +8,7 @@ PART
 	node_attach = 0.0, 0.0, -0.1875, 0.0, 0.0, -1.0
 	TechRequired = advLanding
 	entryCost = 2000
-	cost = 2200
+	cost = 40
 	category = FuelTank
 	subcategory = 0
 	title = Helium tank

Plugin/ModuleAerostat.cs

@@ -31,7 +31,7 @@ namespace Aerostats
         /// Air density at sea level is about 1.2kg/m^3, which means a 1000m^3 balloon will be able to lift about 1 ton at sea level (after substracting the balloon gas weight)
         /// </summary>
         [KSPField(isPersistant = false, guiActive = false)]
-        public float MaxBalloonVolume = 10000;
+        public float MaxBalloonVolume = 15000;
 
         /// <summary>
         /// Weight, in kilograms, of 1m^3 of gas at 100kPa and 0°C
@@ -46,8 +46,8 @@ namespace Aerostats
         /// If the balloon can not store the target amount of gas (because the maximum volume has been reached), the system won't try to inject more gas, to avoid venting through the security valve of the balloon.
         /// </summary>
         [KSPField(isPersistant = true, guiActive = true)]
-        [UI_FloatRange(minValue = 0, maxValue = 20000.0f, stepIncrement = 1.0f)]
-        public float LiftingGasTargetQuantity;
+        [UI_FloatRange(minValue = 0, maxValue = 20000.0f, stepIncrement = 100.0f)]
+        public float LiftingGasTargetQuantity = 100.0f;
 
         /// <summary>
         /// Mass of the empty balloon, in kg
@@ -56,11 +56,10 @@ namespace Aerostats
         public float BalloonEmptyMass = 50.0f;
 
         /// <summary>
-        /// Minimum amount of gas that will be use to inflate the balloon at the beginning.
-        /// This is needed if you want the balloon to lift itself right after staging.
+        /// Minimum amount of gas that will be used to inflate the balloon at the beginning. The balloon can not be deflated below this amount.
         /// </summary>
         [KSPField(isPersistant = false, guiActive = false)]
-        public float MinimumFillQuantity = 75.0f;
+        public float MinimumFillQuantity = 10.0f;
 
         /// <summary>
         /// Drag coefficient of the balloon
@@ -235,7 +234,7 @@ namespace Aerostats
                 if(springLength > restLength)
                 {
                     float tensingLength = springLength - restLength;
-                    springForceMag = Math.Min(tensingLength * SpringHardness, 500000.0f);
+                    springForceMag = tensingLength * SpringHardness;
                     var springForce = springVec * (springForceMag / springLength * 0.001f);
                     part.rigidbody.AddForce(springForce, ForceMode.Force);
                     Balloon.rigidbody.AddForceAtPosition(-springForce, balloonAttachPoint, ForceMode.Force);