A small note about Mk3 tanks

[numerobis]

The new Mk3 adapters are funny: first, they aren't lifting bodies, unlike their Mk2 counterparts. Second, they are now the most efficient tank in the game in terms of fuel mass : dry mass ratio.

In an Mk3 adapter, you get 8 1/3 tonnes of rocket fuel per tonne of dry mass. The Mk2 adapters have 7.5 t fuel:dry ratio, and the Tnn tanks and the Rockomax tanks up to the Jumbo-64 have an 8:1 ratio.

From now on, I'm building all my rockets with Mk3 adapters on them!

[sal_vager]

You're right, they aren't lifting bodies, the shape was considered incorrect for that compared to the Mk2's.

No idea on the efficiency, as long as they aren't negative mass when empty I guess it's fine

[Red Iron Crown]

The Mk3 series are the best tanks in terms of mass ratio, but that advantage is somewhat mitigated by their high cost and capacity. It is often better to have multiple smaller tanks that can be staged away when empty.

[Temeter]

The efficiency makes sense. Take a close look at the tanks, the MK3-stuff is disgustingly expensive. You don't want to make rockets out of that stuff.

edit: It also makes almost no difference. It's a fueltank with 1% more efficiency.

Edited December 19, 2014 by Temeter

[Xavven]

The efficiency makes sense. Take a close look at the tanks, the MK3-stuff is disgustingly expensive. You don't want to make rockets out of that stuff.

edit: It also makes almost no difference. It's a fueltank with 1% more efficiency.

The better mass ratio also makes sense from the perspective of the square-cube law. The volume of the tank grows faster than its surface area, so a bigger tank, while requiring more material to build, can hold even MORE fuel proportionally.

Edit: Some reading if you're interested: http://en.wikipedia.org/wiki/Square-cube_law

[numerobis]

It holds less fuel than the big rockomax tanks though, which by that argument should be even more efficient.

[Temeter]

The better mass ratio also makes sense from the perspective of the square-cube law. The volume of the tank grows faster than its surface area, so a bigger tank, while requiring more material to build, can hold even MORE fuel proportionally.

Edit: Some reading if you're interested: http://en.wikipedia.org/wiki/Square-cube_law

Interesting arguemnt, I didn't think about it this way. You have to mind real phsyical implications, though. A heavier rockets needs sturdier materials, making the thing even more heavy.The 3.75 stock-tanks are actually slightly less efficient than the smaller ones.

Reminds me of one story about real rockets. Recently read about one which is so lightly built that it can't support it's own weight when empty, so it needs fuel to support the structure.

[Red Iron Crown]

That's the Atlas rocket IIRC, with its "balloon" tanks that require pressure for integrity.

[numerobis]

If you take volume:area as driving dry mass fraction (which is what you're doing when you invoke square-cube arguments), we'd expect that all the 1.25m tanks have the same dry mass fraction, all the Mk2 tanks have the same, and all the Mk3 and 2.5m tanks as having the same. Adapters would have intermediate dry mass fraction, the average of its two endpoints.

[Red Iron Crown]

Well no, the volume:area ratio changes with cylinder length. There's a reason almost all soup cans have the same proportions.

[numerobis]

Oh, right. Meh, it's not even a constant factor ;P