• 0
Brandenburg

orange tanks fail expectations

Question

Brandenburg    0
Posted (edited)

images in spoiler

The only mod I have is mechjeb.

It has been a while since I played KSP, but recently started again. Today I just unlocked the big orange tanks, and because I have potato PC I thought great, anything that reduces parts is fantastic. structural stability is great too. Since I had plenty of tourist missions, I decided my first use of the orange tanks would be to give an older tourist shuttle a slight revamp. However, I ran into a slight problem.

Despite the orange tanks appearing to be identical to 2x rockomax x200-32, it seems on my game this is not the case. Despite the client displaying them to be identical, and mechjeb showing identical TWR and delta v, when it comes to actually using them it is a completely different story. The only difference between these two rockets, apart from the tanks, are fuel lines and struts, which are placed in the same manner but will just be in slightly differing positions. The shuttle part of the rockets were not changed at all, in fact I even left the solar panels which clip through some fuel tanks just to remove as many variables as possible.

 

I have tested the orange tanks in a handful of ways, (including with the solar panels fixed) and every time they lose out to 2x x200-32. When it is just a probe on top of the tank/s and a mainsail at the bottom, the difference is fairly slight. However, it becomes even more significant if I use the pictured vehicle but remove the first stage radial boosters. Mechjeb claims a TWR of 1.61 for this instance, but as soon as the structural supports are released it will actually fall towards the pad. The x200-32 stack always takes off with decent acceleration.

 

At the moment, it isn't much of a problem. The numbers of parts I could save by using these tanks over other types is minimal. By the time it reached a significant number, the rest of the ship would cripple my cpu. I am very frustrated by it though because of how odd it seems. I haven't noticed (but haven't checked either) of similar issues with other synonymous parts. I have already validated client files through steam. I am very happy to upload the craft files, I am just not entirely sure what a good place for them is. Somewhere that doesn't require sign up would be great.  

 

tl;dr: orange tanks appear bugged on my client

 

edit: image link fixed(?) the second ship in gallery I forgot to show the engineer report in bottom right side, but weight is identical, H/L/W etc all identical or near enough. I have ran other tests all measurements identical, the only things that haven't been tested to be exact are cost and the part count is lower by one or two I think, simply by using the orange tanks instead of the x200-32

Edited by Brandenburg

Share this post


Link to post
Share on other sites

6 answers to this question

Recommended Posts

  • 0
regex    8851

SLT is the same for both craft, burn time is the same for both craft, delta-V is the same for both craft. I can only assume, not being able to see the engines that are ignited on the pad behind the enormous navball, that your staging is messed up after you launch for some reason.

What version of KSP do you have? You might want to consider a reinstall.

Share this post


Link to post
Share on other sites
  • 0

I'm guessing this should probably be in gameplay questions or some similar category.

Anyways, I'm guessing like regex that this is likely the result of a staging messup. I've messed up staging before more times than I can count.

If it just refuses to go away even with proper staging, I would also suggest a reinstall because that is a whacky bug if it is.

Share this post


Link to post
Share on other sites
  • 0
Xavven    641

Give us some craft files if you can and we'll test it in our installs for ya. I'm on 1.3

Share this post


Link to post
Share on other sites
  • 0
Streetwind    3814
On 15.7.2017 at 0:36 PM, Brandenburg said:

The only difference between these two rockets, apart from the tanks, are fuel lines and struts, which are placed in the same manner but will just be in slightly differing positions.

My money is on fuel flow issues - some of your engines aren't getting fed because you mis-placed fuel lines and/or misunderstood fuel flow rules.

A key lesson when testing is the KISS principle. Every part on your test vehicle that isn't either the part being tested or strictly necessary for the test to function is a part that can potentially screw up your test result. Try building your craft without fuel lines entirely, then try to compare your tanks again.

Example:

- Craft 1 consists of a Mk1-2 capsule, two X200-32 tanks, and a Skipper engine.
- Craft 2 consists of a Mk1-2 capsule, one orange tank, and a Skipper engine.

Notice how the only parts apart from the tanks are the engine (necessary for flight) and the pod (necessary for control). Add a nosecone or parachute to taste, if you like. Using the simplest possible vehicle ensures that no unforeseen interaction will make you come to the wrong conclusion.

In a second step, you can then make the vehicle more complex. For example, try a "Heavy" configuration with two additional identical cores (minus the pod, plus a nosecone) attached to the center by radial decouplers. No fuel lines yet! After you verify that this vessel behaves properly, you can then add fuel lines in a third step.

Share this post


Link to post
Share on other sites
  • 0
Snark    6664

Moving to Gameplay Questions, since this seems to be an issue with playing the game rather than a general discussion about KSP.

Share this post


Link to post
Share on other sites
  • 0
bewing    1273

Yeah, I need a craft file. craft files are just text files -- so you can upload them to anyplace that accepts text files. I like to use pastebin. Open the craft file in a text editor, go to pastebin, and then copy/paste the entire document's text into the browser's window.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now