Is it normal to be fighting will early small rockets?

[Gibster]

I'm a veteran at this game (250 hours) and I just started a new mudded career mode after a sandbox which included a lot of heavy lifting and I was just surprised by how unstable my early vessels have been and how much I have to fight with them on the way up. Is this normal, or have I lost some touch with creating small early game vessels? I mean larger vessels also face instability issues but its like a different kind of instability, at least one where its a little more obvious as to the causes (like too sharp a turn or just really top heavy) At the moment I am blaming the instability on my lack of access to fairings but I just don't really know. 

[Pand5461]

Depends on what you are trying to launch and whether you have FAR installed.

Lack of fairings can certainly be the reason. Starting from 1.2.2 at least (maybe 1.0.X, don't remember), the craft has to be streamlined to fly in a stable manner, so launching something with a blunt top is definitely not the best idea. With FAR, this is even more pronounced.

[The Aziz]

Yeah I had that too. Relearning how to fly small things takes some time, but after a while I developed one design that worked every time and was also really easy to fly.

[Starman4308]

3 hours ago, Gibster said:

I'm a veteran at this game (250 hours) and I just started a new mudded career mode after a sandbox which included a lot of heavy lifting and I was just surprised by how unstable my early vessels have been and how much I have to fight with them on the way up. Is this normal, or have I lost some touch with creating small early game vessels? I mean larger vessels also face instability issues but its like a different kind of instability, at least one where its a little more obvious as to the causes (like too sharp a turn or just really top heavy) At the moment I am blaming the instability on my lack of access to fairings but I just don't really know. 

Part of it is potentially craft size. The smaller you are, the more affected by aerodynamics you are, thanks to the square-cube law working against you (until you size up).

For dynamic stability, ensure your center-of-pressure (center of drag) is behind your center of mass. You can still get to orbit with a mildly dynamically unstable rocket, it just means constant corrections because aerodynamics is always trying to pull you off surface-prograde.

While IMO it's cheaty (real-world tanks drain from the top!), it can be productive to set fuel priority so that the bottom tanks drain first.

[Waxing_Kibbous]

I have 2 points that I look for in a launch

1) at 80-100m/s start the turn. You have to baby the rocket at this point, you can steer it but it's best to keep it within the prograde circle.

2) when Ap is at 20,000m you can start horsing the rocket a bit, I'll usually start aggressively steering forward at this point and smooth it out as the Ap approaches 50,000m and then a nice easy turn to 70,000+. I find the rocket is pretty hard to flip once the Ap hits 20,000.

These numbers also depend on the rocket, for me it is more of a feel thing but these are the more common milestones.

Edited February 10, 2018 by Waxing_Kibbous

[Tyko]

can you post any pix of your problem rockets? might help.

[Darth C3P0]

Off topic, but I got 2000 hours, top that

But seriously, I feel that pain. Make sure that your rocket is symmetrical when it comes to outside parts like batteries and scientific experiments, otherwise if you have a lot of junk on only one side it may effect your center of mass. Also make sure you have fins for your rocket.

[MagicFireCaster]

I have to say it depends on how did you choose to spent the early  science. i think by know i've masterd the way i build small craft with low tech, and how i spend my science to improve this small vessels. (go for coupling first, you don't need to build everything in a radial manner and when doing it, make it in short height. Edit:also use engines that have vectoring and not a fixed muzzle for later stages  ) 

Edited February 11, 2018 by MagicFireCaster

[Tyko]

10 hours ago, Starman4308 said:

While IMO it's cheaty (real-world tanks drain from the top!), it can be productive to set fuel priority so that the bottom tanks drain first.

I'm not sure it's entirely cheaty...RL HydroLOX tanks have the LOX tank above the LH tank. This is keeping the densest fuel all the way at the top. 

[Snark]

Moving to Gameplay Questions.

19 hours ago, Gibster said:

I was just surprised by how unstable my early vessels have been and how much I have to fight with them on the way up. Is this normal, or have I lost some touch with creating small early game vessels?

Small vessels are much more strongly affected by aerodynamic forces than larger vessels are-- the result of instability is the same whether you're big or small, but when you're small it happens a lot faster and more dramatically.

Anyway:  The easy solution is to just put fins on them (the Basic Fin works great) and make sure that your CoM is towards the front of the vessel.  As long as the CoM isn't in the back, and there are appropriately placed fins, I've always found that they fly just fine-- no stability issues at all.

Could you post some screenshots of vessels you've been having trouble with?

[HvP]

Also consider this, in the early game the rockets are much lighter but you quickly gain access to some relatively powerful engines before you unlock the heavier payload components.

A high thrust-to-weight ratio will cause a light rocket to hit a wall of air soon after launch. This does not pair well with a light and draggy nose which can cause a rocket to flip out. Alternatively, if you put a good pair of fins at the back you can actually end up with a rocket that is far TOO stable and hard to steer if you don't reduce your thrust in the heavy atmosphere.

Edited February 12, 2018 by HvP