Nuclear Engine Fairings

[Kerolyov]

Having trouble with centre mounted nuclear engine as nearly always hav an issue with an explosion after staging and it seems it is possibly the fairings of the nuclear engine that hit external fuel tanks or monopropellant tanks or the engine itself detaches.

Has anyone else had this issue?

EDIT: Below are of low level test after first failure in orbit. Craft will be interplanetary, hence the nuclear engine design, I'm not intending going anywhere after staging jsyt see if it works then spalshdown. My originhal aim was first mount fuel tanks radially around the central engine to avoid the craft being long. This always exploded so tried bigger tank and monopropellant at the back....., still exploded as seems the nuclear fairings can hit and tanks near them

Going ok.....

Then stage and boom!

Edited May 20, 2013 by Kerolyov

[Scotius]

Looks like the fairing is smashing into monopropellant tanks on the craft's bottom. Try to place them in different spot.

[SoldierHair]

Do you activate the engine in the same time you decouple?

At that altitude the nuclear engine wouldn't work the way you want it too anyway , it doesn't have the thrust to lift things on Kerbin

[SecondGuessing]

Looks like the fairing is smashing into monopropellant tanks on the craft's bottom. Try to place them in different spot.

This, or set up the staging so the stage and the nuclear engine are on different stages and leave a second or two between them. It could also be that you don't have any struts, especially from the capsule to the large tank (the large ASAS has absolutely useless tolerances, and will snap at the smallest wobble).

Plus, you're going oddly horizontal given how low it seems you are, although I've never looked down again when launching so who knows.

[Kerolyov]

Do you activate the engine in the same time you decouple?

At that altitude the nuclear engine wouldn't work the way you want it too anyway , it doesn't have the thrust to lift things on Kerbin

Actually this is a low level test with less boosters after my first ship blew up upon staging in orbit scattering debris everywhere, this way I test at low altitude until I have the nuclear staging working. The craft will be interplanetary when I've got it working hence the nuclear engine.

Thanks for the advice, looks like either mount 2 nuclear engines radially or keep the fairings clear of fuel tanks. Why do nuclear fairings come off so much more explosively?

[23278]

I HATE the fairing on the LV-N's. It makes launching some of my ships with clusters of nukes rather difficult.

[Gabe]

I was having this problem last night and couldn't figure out what I was doing wrong. I tried starting the engine separately from the staging, with the same result. It is somewhat comforting that it might not be my error.

Edit: I was also using the large to small cone and I wonder if that might be the problem.

[astocky]

Seems to me like the ring of RCS tanks are sticking too far down towards the nuclear engine - they seem to be overlapping in the first pic. I think the fairings are hitting the RCS tank which is exploding and making bad things happen. Try mounting them up the top near the capsule and see if you have more luck.

[RoboRay]

At that altitude the nuclear engine wouldn't work the way you want it too anyway , it doesn't have the thrust to lift things on Kerbin

At 10km altitude, the LV-N's Isp is over 700, so you can go ahead and start them (if their nozzles aren't obstructed by a lower part of the ship) without a serious efficiency loss. They do lack the thrust to be the only engines firing, though, as you noted.

[Kerolyov]

Glad to know I'm not the only one Gabe & 23278!

Ok tried with split staging (ie stage to decouple, then pause and stage again to light the nuclear bomb stapped to Jebs backside) and boom! Tried moving the RCS tanks and staging in one go and it worked. So I'm just going to accept the length of the re-design and get to those planets (serves me right for trying to be clever), wish me luck on my first trip beyond Minmus (I'm off for an orbital trip to Eve and back).

[SecondGuessing]

Glad to know I'm not the only one Gabe & 23278!

Ok tried with split staging (ie stage to decouple, then pause and stage again to light the nuclear bomb stapped to Jebs backside) and boom! Tried moving the RCS tanks and staging in one go and it worked. So I'm just going to accept the length of the re-design and get to those planets (serves me right for trying to be clever), wish me luck on my first trip beyond Minmus (I'm off for an orbital trip to Eve and back).

The issue is the ASAS: it has a tiny impact tolerance, and so it breaks from the change in acceleration when you eject the fairings. Add struts from the capsule to the large tank.

Edit: Oh wait, you said it worked. Doh!

[Gabe]

I had struts on my ship near the engine and I'm not sure if the fairing is hitting the struts. I will have to check it out when I get out of work tonight.

I wish there was a sepratron strut that you could decouple before staging.

I could do it with the struts on decouplers but I'm trying to keep the part count down. My laptop starts chugging when the count gets even moderate.

I'm waiting until the 780m comes out before getting a new laptop.

[Caelib]

I have experienced this problem and I have moved to a model where I use two radial mounted engines instead of one -- the below image shows MANY radial mounted engines, but I would only recommend using two since it's a lot of additional mass:

[NeoMorph]

I had some REAL problems with the nukes in my early days. Stage a lower level and something would go boooooom on my nuke upper stages.

So now I cheat lol. I make my nuke engines the LOWER engines and stack asparagus instead of vertical.

How do you like these Nukes...

[Richy teh space man]

I got around this by right clicking on the engine then activating it. When I switched back to it I found the fairings had disappeared.

[SciMan]

You know, I had this problem too, but I solved it by performing a small .cfg edit

In the "part modules" section of the part.cfg for the LV-N, you should see two part modules with "name = ModuleJettison" as the first line inside the {curly brackets}. In both of those modules, look for a line that says "isFairing = False" and change it to "isFairing = True". Doing that makes those pesky fairings on the LV-N stay stuck to the decoupler of the stage under them, allowing you to make "telescoped" designs like the ones mentioned in this thread. I don't mind making this kind of small .cfg edit, as it's just removing a source of minor annoyance, not the type of change that turns the game into "easy mode" (like a tiny engine with 4000 thrust and 10000s isp might be, for example).

[TheHengeProphet]

You could stage with a hotkey, activating the engine and decoupling without ejecting the fairings. I do this on my special NERVA plane that goes from 1700m to orbit on one tank of fuel and one LV-N, because if the fairings detatch, it will catapult the engine straight off the plane.