Okay so I'm having an issue with the mod.
I have a space plane and I replaced all the small tanks for single large ones that make the exact same lengths (using tweakscale of course.)
Now while the new tanks have less fuel and over all it reduced weight and part count, and after tests it did not affect the max thrust of the engines at full throttle or airflow intake while at a stand still, there was a massive reduction in acceleration and top speed, I mean a huge reduction.
I tested this with to planes, exactly the same, one using smaller default fuel tanks end to end to make the proper length and the other using Fuel Tanks Plus. All tests show the engines performance are the same but something is holding the FTP plane back from accelerating past 120ms and thus I can't get it to stay in the air.
Any Ideas as to the issue?
Before you ask, yes that is the only difference between the planes.
EDIT: I did the math and it's between a 36-37% lose of acceleration by the time it hits the end of the KSC island runway.
Stock plane hit 202 at the end of the runway, FTP mod plane was 129.
Stock Plane weight is 19.1t, The FTP mod plane weight was 19.1t
Stock Plane engine output was 119.9 at full throttle breaks locked on the runway.
The FTP plane engine output was 119.9 at full throttle breaks locked on the runway.
The only thing I can think of is that when I Tweakscale the parts there weight and fuel change but somehow there aerodynamic profile does not, thus increasing drag.
That is my only guess.