Cute 3D video of Angara A5 production, assembly and launch proccess

[1greywind]

Searching google for news regarding upcoming december maiden flight of Angara A5 I've found this cute video:

https://www.youtube.com/watch?v=jmT6UR0sjUA&feature=player_detailpage

It is a little dated (2012) and has giant watermark across entire frame, sorry. I wish we someday get something like this in KSP: imagine "assembly line" and then "roll out" sequence after you click "launch" button in VAB.

Edited November 4, 2014 by 1greywind
bad video url

[Red Iron Crown]

That is pretty darn cool, thanks for sharing.

[Camacha]

Is this accurate, as in, coming from an official source? If it is, it does answer a couple of questions I've had for a while now and a couple more. Especially the rings to keep everything nice and round are a simple solution to a problem I had not considered fully.

Does anyone know why the sides of tanks are smooth, but interstages are ribbed? I have wondered about that for a while.

Edited November 4, 2014 by Camacha

[1greywind]

Is this accurate, as in, coming from an official source?

I don't know is it 100% accurate, but this footage is widely used on russian TV (i.e.

).

On ~1:45 in video below you can see interstage between first stage (URM-1) and second stage (URM-2).

And this

gives nice look onto semi-assembled tanks of URM-1s for upcoming Angara A5.

[TheShadow1138]

Does anyone know why the sides of tanks are smooth, but interstages are ribbed? I have wondered about that for a while.

If I'm correct, they are called "stringers". They are used to provide a more rigid structure with less of a weight cost. In aircraft, as presumably in rockets, they are used to transfer aerodynamic forces acting on the skin to the frame of the vehicle. The use of stringers on the interstages, and on occasion between the tanks on a single stage (such as the S-IC stage of the Saturn V) to provide a stronger structure while saving mass.

Someone feel free to correct me if I'm wrong here.

[Bill Phil]

If I'm correct, they are called "stringers". They are used to provide a more rigid structure with less of a weight cost. In aircraft, as presumably in rockets, they are used to transfer aerodynamic forces acting on the skin to the frame of the vehicle. The use of stringers on the interstages, and on occasion between the tanks on a single stage (such as the S-IC stage of the Saturn V) to provide a stronger structure while saving mass.

Someone feel free to correct me if I'm wrong here.

The Russians fire stages while the one below is still firing. The gaps are so the exhaust can escape.

[Camacha]

If I'm correct, they are called "stringers". They are used to provide a more rigid structure with less of a weight cost. In aircraft, as presumably in rockets, they are used to transfer aerodynamic forces acting on the skin to the frame of the vehicle. The use of stringers on the interstages, and on occasion between the tanks on a single stage (such as the S-IC stage of the Saturn V) to provide a stronger structure while saving mass.

Sure. But why not build the tank the same way? I have not been able to come up with a reason why a solution good for one would not also work for the other. The only slightly viable story is internal pressure, but that does not sound like the whole story.

The Russians fire stages while the one below is still firing. The gaps are so the exhaust can escape.

The discussion was about the ribs, not about any gaps

[Red Iron Crown]

Sure. But why not build the tank the same way? I have not been able to come up with a reason why a solution good for one would not also work for the other. The only slightly viable story is internal pressure, but that does not sound like the whole story.

I think pressure is the big factor. A corrugated tank would swell like a balloon under pressure, especially on upper stages that operate in thin or negligible atmosphere. The interstage only has to resist forces in the thrust direction so the lighter ribbed structure is better. A tank has to be strong for those compressive forces and the tension forces of the internal pressure they contain, so a cylinder is stronger in the right directions per unit mass.

[TheShadow1138]

Sure. But why not build the tank the same way? I have not been able to come up with a reason why a solution good for one would not also work for the other. The only slightly viable story is internal pressure, but that does not sound like the whole story.

I would imagine that since the tank sections must be constructed to withstand the pressures after they are fully fueled, that they are already sufficiently strong enough to deal with the physical and aerodynamic loads during flight. So these sections are where most of the mass for the stage is concentrated allowing them to build them with smooth skins while the sections between, and/or at either end of the stage, and the interstages are shells, with no top or bottom, where conserving mass would be easier to accomplish. Thus it would be these sections where the stringers, or ribs, would be a better choice for lightweight, but strong structural sections. It may be because building the tanks as the interstages are built would mean that they would not be strong enough. We have to remember that the tanks endure radially outward forces exerted by the expanding fuel and oxidizer as well as longitudinal forces during flight whereas the interstages, intertanks, and fore and aft skirt assemblies only have to cope with longitudinal forces during flight.

Again, I may be farther off base than I believe I am, so someone feel free to correct me if I am incorrect.