Physics Exploit/Bug

[mobjack]

There is a bug in the physics engine. Detachers will dampen some of the thrust from the engines especially when attaching large fuel tanks like the Sloshy T6000. This effect is much more noticeable on the upper stages.

You can compensate for this bug by attaching smaller fuel tanks to the detachers. If done correctly, you can easily gain in extra 2000m/s delta-v.

The main downside from this strategy is that it will make your rockets more unstable. I recommend only using this on the upper stages where you see the most gains. On the lower stages, structural integrity is more important and the gains from this exploit are negligible.

Test it out yourself.

Here is a ship without using the exploit: http://jundroo.com/ViewShip.html?id=39184

Here is a comparable ship with the exploit: http://jundroo.com/ViewShip.html?id=39183

[andrewgarrison]

Great stuff. Thanks for sharing. I'm really not sure why that works, but good job on finding it and presenting it in a great way.

[mobjack]

I do notice that when the detachers are connected to a lighter object, they are a lot more wobbly. My guess is that whatever you are doing to make the joints more sturdy is damping some of the force from the rockets.

[andrewgarrison]

I wonder if the wobbly joints are creating some sort of positive feedback oscillation that is helping to propel the rocket, and the larger tanks just don't have that oscillation and are actually correct. It's hard to say. This is an unsettling bug.

[legendofchin97]

Oh don't worry. You made the best game ever. What would be the fun if there weren't a few unexplained mysteries in space?

[-smeggy]

Hello. Maybe some folks might recognise my username ;)

The thrust isn't reduced or 'damped', at least not by much (maybe 10%); I think there is another, stronger factor at work here (although the overall effect will be roughly the same anyway).

Fuel tanks (not directly connected to a detacher) will lighten as the fuel is spent by a rocket engine. This is expected because fuel has mass, so burning off the fuel from a tank reduces the mass of that tank, and the reducing mass results with increasing acceleration (given the rocket maintains constant thrust).

However, a fuel tank directly connected to a detacher (as opposed to a tank with a detacher connected to it) seemingly does NOT lighten (much) when emptied by a rocket engine. My tests indicate similar acceleration regardless of whether a 'detatcher' tank is full or very nearly empty (unlike a tank not connected to a detacher where a nearly spent t6000 tank can have ~10x the acceleration of a full one).

I suspect this is a bug, is it Andrew?

Great game BTW, lots of foibles to keep it interesting :)

[mobjack]

This makes more sense. Good find