Make the parts more balanced

[NWM]

Now two special engines had been rendered to almost useless: the NERV and the Aerospike.

The Aerospike is useless - heavy, weak, has no gimbal, but at least very sensitive to the atmospheric pressure. The Isp drops from 340s to 290s at 1 bar. Hey, what is that spike for? Why are the values not 340 and 335?

The Nerv is more heavy, and lost thrust vectoring, and consumes LF only, having no role now, as purely inferior to the Poodle. At least that thrust vector should be remained, at least 0.5 degrees...

The smaller fuel tanks are ridiculously overloaded in comparison to the bigger ones. And why have the durable aeroplane fuselages better wet/dry mass ratio?

And a question: why we use LF/OX in ratio of 9/11? The 8/12 ratio is more realistic and easier to count as it is simplified to 2/3.

And why haven't these LF+OX tanks got a tweakable switch to work as pure LF tank - making the Nerv usable again...

[Red Iron Crown]

I have to disagree with your assessment of the aerospike and Nerv. The aerospike is a great rocket engine for spaceplanes, it's short, quite efficient and has a better TWR than the LV-909 Terrier. The Nerv is still the go-to engine for interplanetary work, its high Isp makes it better than just about everything else provided you use the LF-only tanks, not LFO tanks with oxidizer tweaked out. Though I would certainly agree that we are missing some sizes of LF tanks, and a tweakable for fuel type would be the ideal solution for that.

I'm not 100% sure what you mean by "The smaller fuel tanks are ridiculously overloaded in comparison to the bigger ones." Can you clarify?

[CaptainTurbomuffin]

I will soon post a suggestion thread about balancing airplane engines. And nukes. Currently I am working on a test-mod of it. The fuel ratio is unrealistic, and bad, but if it was changed right away, the whole spaceplane-system would have to be re-balanced. 1m parts were never over-fueled. In fact, an 1m part has exactly the quarter fuel of a 2m tank, with the same height. Dry aircraft tanks are lighter than dry rocket tanks with a reason. In past, with the old mk.3 parts, this ratio was even worse. Not only for the fuel tank should get a tweakable, but all parts. But hey, I tried to build a nuke-powered interplanetary craft, and I used the 1 m LF fuselage. The craft became awesome (in sight, not in performance)

[Laie]

The Aerospike is useless - heavy, weak, has no gimbal,

Realistically, aerospikes have a worse TWR than ordinary engines, and while superior in the ISP departement, they are no miracle machines. In the most recent upgrade, it's weight has been brought down from 1.5t to 1t, so now it's TWR is already rather good. By the way, that curve doesn't stop at 1 atm: As pressure increases, every other engine fares far worse. On sea level Eve, the Aerospike can compete with Mammoths, pound-by-pound.

Personally, I still wish there wasn't such a huge performance gap between 1.25m and 2.5m engines; but if you compare the Aerospike to LVT30/45, it's a very good engine. It even holds up reasonably well compared to Poodle or Skipper.

[NWM]

The aerospike should outclass the others with conventional nozzle at high pressure - thats what they are developed for. Its mass maybe needs some re-correction to 1.25, or something like this. (better Isp at high pressures, and a bit worse TWR)

The NERV is drowned by great dry masses, both own, both the fuel tanks (if you won't use Mk3s)...

Smaller tanks example: FL-R25 250 units (1.25m), and FL-R1 750 units (2.5m). The ratio is 1:3 instead of 1:8 should be derived from dimensions. Others: Oscar, Round-8, FL-R10, Stratus-Vs...

[Red Iron Crown]

IRL aerospikes are inferior to bell nozzles at the pressure for which the bell is optimized. I.e. a sea level optimized bell will outperform an aerospike there, a vacuum optimized bell will outperform an aerospike there. The aerospike's advantage lays in losing less performance away from its optimal conditions, that same aerospike will stomp the sea level optimized bell everywhere but sea level and the vacuum optimized bell anywhere but vacuum.

This characteristic makes them appropriate for designs that have an engine burn continuously through the launch, they are less appropriate for serially staged design where more specialized engines can be better.