Push versus pull

[Conarr]

I know this was covered somewhere, even one of Scott Manley's videos apparently, but I can't find it. What I want to know is your opinion on having an interplanetary tug push a payload versus pulling a payload. In other words, put the tug behind the payload or in front of it? I'm testing with my space station now (well last night) and the only thing I've noticed so far is that it seems easier to keep it on course when you pull. Any thoughts about efficiency etc?

[Scotius]

I have two tug designs currently in space. One can pull (due to a brain fart i installed only small clamp-o-tron on the nose), and second (bigger one) can both pull and push. It uses 4 SM-FFR engines from the mod, but it could work with 4 NERVAs i think. In both designs engines are mounted on the ends of long trusses, and every truss ends with a RCS thruster for maximum leverage. My bigger, 77 ton tug is surprisingly maneuverable and stable under thrust when pulling something. I haven't tried to push anything on the size of jumbo fuel tank with it yet. I noticed one important thing: when using long engines on the end of trusses, it' important to watch where Center of Mass is and connect trusses avove CoM - this way engines don't stick too far, which creates problems with maneuvering.

[magnemoe]

Depend, long items should be pulled as they tend to buckle if pushed. Heavy things like sets of orange tanks should be pushed as they might decouple if you have high trust.

This ship pulls an huge miner who weight more than 5 orange tanks, works as I use docking struts, if I forget them it would either separate or break.

[sal_vager]

I don't know if it's better or worse but I just prefer tugs that put the load in front, much like a forklift truck does, plus it makes changing the payload in the VAB a lot easier, all I need to do is build it on top of my basic launcher/tug combo

[Pursuedtank]

I always prefer to pull, because of the tendency for it to sway to one side if pushed.

[loppnessmonsta]

It had never really occurred to me to pull longer stuff, since you need to build out and the exhaust can damage your stuff. But then, my space program is in its Design phase, and unlikely to get much beyond that. I'm too impatient to be a good pilot.

[SecondGuessing]

I have a space tug which can do either, but I typically use it to pull as it's mostly used to ferry lines of orange tanks within the Kerbin system. My frigate, which I used to transport heavier landers/rovers/modules within Kerbin, have to push, but that's okay as the payloads are pretty short.

[andrewas]

Look up the 'pendulum fallacy' for why this doesn't matter for rigid loads. For flexible loads, or loads which don't take compressive forces well, pulling may be the only option.

[Trux]

I prefer pulling, it produces less wobble than balancing a payload and pushing it without struts. But if I am building from the VAB then pushing in the obvious option with the ability to strut the pieces together.

[Ekku Zakku]

I'm definitely one to push, since I don't usually do a lot of base building that would more efficiently work by carrying more at once. I instead like to go on long journeys to other planets with reasonably sized landers, where I think pushing is better since I think gimballing engines will have a slightly better effect. It's also a lighter, not having to build the engines radially and outwards. All in all, I think most people would agree that it depends on the payload.

[Conarr]

Thank you all. It seems to me there isn't a clear consensus on this. I will say that I've done some more testing tonight, after I had to re-install due to not being able to end any flights and with stock only parts at the moment, it seems pull is easier to pilot. I can't see a clear difference in efficiency either. Apparently it doesn't matter on your gas mileage if you push or pull. I guess it's a preference thing then. Again, thanks for the input.