Help! Building a new engine, but it has no thrust or vapor trail.

[SirJoab]

Hi guys,

I'm just getting into part building and it's gone well up to now. I'm building a tiny Monopropellant engine with built-in fuel storage. I first developed the .cfg file using the LV-1 "Ant" engine and it worked fine, but when I made my own model then engine now starts up, uses fuel, and makes noise, but produces no thrust, and has no vapor trail.

When I replace the model with other ones the engine works again. This make me think the problem is somewhere in my model...

First I modeled the engine and saved the .blend file:

Then opened the .blend file in Unity:

Then I added a collision mesh:

And packed the file with KSP Part Tools:

And just for reference, here is my .cfg file:

PART
{
name = JAT_CubeSat1-2UpropulsionUnit
module = Part
author = JAT

mesh = model.mu
scale = 1.0
rescaleFactor = 0.5

node_stack_top = 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0
node_stack_bottom = 0.0, -0.025, 0.0, 0.0, 1.0, 0.0, 0

fx_exhaustFlame_white_tiny = 0.0, -0.025, 0.0, 0.0, 1.0, 0.0, running
fx_smokeTrail_light = 0.0, -0.51, 0.0, 0.0, 1.0, 0.0, running

sound_vent_medium = engage
sound_rocket_mini = running
sound_vent_soft = disengage
sound_explosion_low = flameout

entryCost = 10
cost = 350
category = Propulsion
subcategory = 0
title = JAT-TP Self-Contained-Propulsion Unit
manufacturer = JAT Research Labs and Toilet Paper Co.
description = Self-Contained Monopropellant Propulsion Unit. Also makes a terrifying woopie-cusion.
attachRules = 1,0,1,0,0

mass = 0.0005
dragModelType = default
maximum_drag = 0.2
minimum_drag = 0.2
angularDrag = 2
crashTolerance = 60
breakingForce = 2500
breakingTorque = 2500
maxTemp = 3600

stagingIcon = LIQUID_ENGINE

MODULE
{
	name = ModuleEngines
	thrustVectorTransformName = thrustTransform
	exhaustDamage = True
	ignitionThreshold = 0.1
	minThrust = 0
	maxThrust = 0.2
	heatProduction = 30
	fxOffset = 0, 0, 0.08
	PROPELLANT
	{
		name = MonoPropellant
        	ratio = 1.0
		DrawGauge = True
	}
	atmosphereCurve
 	{
   	 key = 0 170
  	 key = 1 155
 	}

}

RESOURCE
{
	name = ElectricCharge
	amount = 0.0
	maxAmount = 0.1
}

RESOURCE
{
 name = MonoPropellant
 amount = 2
 maxAmount = 2
}

}

Any ideas about what's going on? Are there any engine-specific tutorials I can follow step-by-step?

[NoMrBond]

You need to (in Unity)

1. add another empty GameObject to your project
   
2. rename the new GameObject to thrustTransform
   
3. make the thrustTransform object a child of your model
   
4. position the thrustTransform object where you want the engine thrust to come out
   
5. point the thrustTransform objects blue arrow in the direction you want the thrust to go
   

[Edit] Hope that helps, otherwise there are more examples in the engine section of the modding information thread

Edited January 28, 2014 by NoMrBond

[SirJoab]

Brilliant! Problem Solved.

[NoMrBond]

Great news, best of luck with the modding!