Reentry modules are draggy, uncontrollable garbage that will flip a rocket 90% of the time.

[Frostiken]

What a horrible idea, what an untested, awful concept. I feel genuinely ripped off by these.

Make a bog-simple rocket. Parachute, reentry module, a liquid fuel tank with a Valiant engine, a decoupler, a few more tanks with a Swivel, and maybe two SRBs for good measure. Put all the fins you want on the bottom. This is the absolute most vanilla low-tech orbital rocket and is the rocket pretty much everyone uses to get into space.

Every single time, at around 12,000 meters in the middle of the gravity turn, that awful, AWFUL AWFUL pod on the top will grab the airstream and flip you over.

Not even computer-assisted ascents like Mechjeb or GravityTurn can cope with how uncontrollable these wretched things are.

Now, strip the reentry module off and put a Mk1 instead. Tadah, your rocket is now as stable as a redwood.

PLEASE do something about these terrible pods. They're borderline UNUSABLE as-is. 

 

The only way I can get one to orbit is with ENORMOUS amounts of huge fins on the bottom, or a payload fairing, both of which are not ideal for low-tech early missions, which is when I would be using the reentry modules in the first place.

Edited October 14, 2018 by Frostiken

[Tyko]

Are you talking about the MH Onion module and its improved versions?

If so, it's not really intended to be aerodynamic. It's modeled after the early Vostok capsules which were launched inside a fairing for aerodynamics.

Try using a fairing   

Edited October 16, 2018 by Tyko

[fourfa]

Fairings don’t come until much later in the career tech tree. He’s right, it’s damn near impossible to use these pods in early career

[Tyko]

On 10/17/2018 at 12:13 PM, fourfa said:

Fairings don’t come until much later in the career tech tree. He’s right, it’s damn near impossible to use these pods in early career

Yep, it's annoying. In my game I call the Onion a "test capsule" designed to test systems. I run tests on the ground, in low atmosphere and I use a small rocket to boost them into the various nearby biomes. After that I switch to the much better Mk1 and never touch the Onion again.

If you're looking to build Russian/Soviet style rockets and don't mind mods just download Tantares. Then you can build entire Soyuz craft plus many many other things.

 

[OHara]

For some reason, the kv1,2,3 pods have custom-configurations for their drag, with values of a flat-plate facing each of the x,y,z directions instead of the default values from its shape.

A ModuleManager patch to remove the custom drag

@PART[kv?Pod] {
    !DRAG_CUBE {}
}

makes launches easy. This removal also makes the round pods slippery on reentry.  The three pods have the same outer size and shape, but very different masses, so re-entry with the 3-man kv3  pod requires extreme care and drogue chutes.

That configuration entry very much looks like an un-finished attempt to make the kv3 re-enter more easily.  

Edited October 22, 2018 by OHara
given the bottom only a higher Cd=0.8, as if a flat section was revealed on de-coupling, makes re-entry reasonably easy, though still different than with the mk1 pod.

[micha]

I had the same problem; one thing I failed to notice was that they don't have reaction wheels, unlike the Mk1 pod.

Still, they are far less aerodynamic than the Mk1, so much more care is required to get them to orbit. But with a bit of practice, I had no problems.  Just have to throttle down a bit while they are going through the upper atmosphere and make sure the gravity turn is nice and slow and smooth.

Still, I'd argue that a basic fairing for these pods should be available very early in the game.

[OHara]

37 minutes ago, micha said:

one thing I failed to notice was that they don't have reaction wheels

The drag configuration in 1.5.1 stock leads to 200 kN drag force on the pod as you go through the sound barrier,
so even KSP's comically over-powered 15-kN-m reaction wheels would be overwhelmed when that pod drifts a few cm from prograde.

Fins would be the natural countermeasure, but you need a surprisingly large area of tail-fins because those kv1 pods are so surprisingly draggy.  Fourfa's image in the other thread makes the point well

There's a bug-tracker item 20268.  Now that I've re-entered all the pods with natural drag, I'll add the suggestion there to make the kv1 pods' drag match their visible shape.

[micha]

1 hour ago, OHara said:

The drag configuration in 1.5.1 stock leads to 200 kN drag force on the pod as you go through the sound barrier,
so even KSP's comically over-powered 15-kN-m reaction wheels would be overwhelmed when that pod drifts a few cm from prograde.

Fins would be the natural countermeasure, but you need a surprisingly large area of tail-fins because those kv1 pods are so surprisingly draggy.

*shrug* I was just reporting that with a little bit of care and practise , you can get a "normal" rocket (4 static fins) into orbit with these pods, once you understand how they fly. Real rockets throttle down for Max Q too, and if you do that with these pods and are careful not to overthrottle in the upper atmosphere they are fine.

It's not just too much drag; it's a combination of too much thrust at the back and too much drag at the front that's causing these rockets to flip.   Longer rockets help.
 

[Tyko]

Here:

@PART[fairingSize1]
{	
	@TechRequired = start
}

If it were my game I'd actually move the pod and the fairing to simple rockets, but the change above is the simplest option

[DDE]

On 10/17/2018 at 10:13 PM, fourfa said:

Fairings don’t come until much later in the career tech tree. He’s right, it’s damn near impossible to use these pods in early career

Which only serves to expose how absolutely borked the game's tech tree.

Sandbox forever.

Edit: pardon the necro; this subsection of the forum is more deserted than I expected.

Edited January 6, 2019 by DDE

[Fraston]

Just don’t use it, if you don’t like it, don’t use it, you are supposed to use them with reaction wheels, which are midway into the tech-tree anyway. I haven’t put one on any of my crafts since summer last year.

[Gapone]

They are intended to be draggy: they are reentry modules and should quickly brake in the atmosphere.