Barujin

You can use a double adapter and then attach two more double adapters to it, rotated the other direction. That easily gives you four. I don't know how stable this would be on a launch setup, though.

Instead of adding tanks above tanks, can you add the tanks to the sides and put engines on them? I'm guessing that you might get more stability that way (plus more thrust). When staged, you'll be able to shed the dead weight of those extra tanks, too.

I've apparently figured out the problem with my design that is twice the plane of the Aeries 4. I had two aerospike engines next to each other in the center and four jet engines, two on either side of the aerospikes. I noticed that the overheat problem in the aerospikes was forcing me to lower the throttle more than if they are separated from each other. So, I reversed the positions of the rockets and the jet engines. Aside from making the plane generally unstable for flying, it also reversed my problem. Now, my jets were cutting out at 18Km instead of 22Km while the rockets ran at a higher throttle. If I can do a design that separates all engines from each other, then I might make the double plane work. The irony is that it's not worth it because it apparently does just as good as the Aeries 4. I figured that more plane would go further. Apparently not. Obviously, I'm new at this.

Okay, being new to Kerbal, I hadn't tried actual rocketry yet. I just was really interrested in the whole space plane concept. I finally made a rocket with aerospikes and one striped tank for each one. The one without staging could not make it into orbit (without really smart maneuvers). Once I added ordinary staging, though, it worked perfectly. I realized that rocketry truely functions due to dropping the extra weight. If someone could get a huge amount of fuel up to 20Km safely and with little extra weight, then they could likely get into orbit and go to other planets. Otherwise, I just don't see space planes as realistic (take-off to landing). Tiny doesn't exactly get far out there.

I started playing Kerbal at version 0.2. I've been trying to get into orbit with a space plane after watching Scott Manley's YouTube video about them. He got into orbit with an optimized Aeries space plane with plenty of fuel to spare. I built a similar plane with twice the fuel, two aerospike rockets, four tanks of jet fuel, and four jet engines. I can get 1 Km/S of speed at 20 Km altitude, but the plane burns through its fuel before reaching 40 Km. What am I doing wrong? Did something in Kerbal change with a recent version or does the plane simply have too much weight? I thought everything would scale up just fine, but I guess it doesn't. I'll try building exactly the same plane that Scott Manley built and see if it works.