Rapier Engines are not getting Oxidizer but get Fuel in SSTO

[MeepTicoMeep]

I am making a SSTO but it appears that the engines don't get oxidizer. I tried putting external fuel ducts but they still flameout. I don't know what I am doing wrong.

Craft File:https://drive.google.com/open?id=1E_BGlwit6HHBLCkCBrB4oMWBRG8-3WwW

[Geonovast]

Those mounting pylons you have the engine nacelles attached to are actually decouplers.  You need to enable crossfeed on them.

Interesting design, by the way.  I'm curious to see if it works out for you.

You might also want to disable staging on those guys so you don't accidentally jettison them in flight.

[MeepTicoMeep]

17 hours ago, Geonovast said:

Those mounting pylons you have the engine nacelles attached to are actually decouplers.  You need to enable crossfeed on them.

Interesting design, by the way.  I'm curious to see if it works out for you.

You might also want to disable staging on those guys so you don't accidentally jettison them in flight.

Thanks. The SSTO becomes unstable though when it hits space.

[Geonovast]

Just now, MeepTicoMeep said:

Thanks. The SSTO becomes unstable though when it hits space.

I noticed that when I took it for a test drive.

Your CoM and CoT are a bit out of alignment, so the thrust is forcing it to nose down.  Rapiers have gimble, but not enough to compensate for the amount of offset you have.

 

[MeepTicoMeep]

46 minutes ago, Geonovast said:

I noticed that when I took it for a test drive.

Your CoM and CoT are a bit out of alignment, so the thrust is forcing it to nose down.  Rapiers have gimble, but not enough to compensate for the amount of offset you have.

 

Oh, ok,

Is this any better?

 

(edit) turns out I didn't have enough oxidizer

Edited November 10, 2018 by MeepTicoMeep

[bewing]

AFAIK, rapiers do NOT have gimbal.

And yes, it looks like you have things nicely aligned in that pic now.

Edited November 10, 2018 by bewing

[MeepTicoMeep]

7 minutes ago, bewing said:

AFAIK, rapiers do NOT have gimbal.

They have a 3 degree gimbal. But it barely does anything.

[bewing]

ah

[MeepTicoMeep]

So, now everything is fine, I just need to add Oxidizer so Jeb doesn't fly at orbital velocity at the ocean again.

[Geonovast]

I would focus on trying to lose some weight first.  For one, you may be bringing along too much LF for the ascent.  Make sure the fuel priority on the nacelle tanks is higher than the LFO tanks in the middle, and see how much you use before the rapiers switch.  Then load them with just a little bit more than that.

Also get rid of the little landing gear behind the main gear.  Not sure what that's for.

 

[bewing]

preventing tailstrikes, probably.

[Guest]

On 11/11/2018 at 12:47 AM, bewing said:

preventing tailstrikes, probably.

Whosoever hath not had a tailstrike, hath not designed a plane in KSP.