@SledDriver
Thank you and I will use the balance tool next time

@Mastergamer117 Here you go, I've fixed it for you. What I've changed:

• made the fuselage longer to move the center of mass (CoM) ahead of the center of lift (CoL);
• gave the inboard (center) engine half the mass and twice the power; and
• gave the two outboard engines twice the power.

I've also cut the spin-up time for all engines to one-quarter of the normal value. This causes them to reach full power more quickly, and also cuts down on engine noise.

Now it flies great, with and without the inboard engine enabled.

Learn to use the balance tool (when you open the menu, in the two rows of square buttons, it's the one with the balance icon). It'll show you the CoM, CoL, and center of thrust (CoT). CoM always needs to be ahead of CoL. CoT needs to be in line with the axis of the aircraft, and slightly below the center of mass (to counter the nose-down tendency).

@SledDriver
Which engine multiple should I use

@SledDriver
I just published the newest model and I used negative weight fueltanks

@Mastergamer117 Yeah, those look like they might do the job.

@SledDriver
This is what I found
https://www.simpleplanes.com/a/h2n1qR/MOD-engine

@SledDriver
Ok I'll go look for some

And happy New Years

@Mastergamer117 Engines can be modded to have more power, shorter spin-up time, and make less noise. Wings can be modded to not flex, and scaled so that what looks like a small wing can have enormous lift.

@SledDriver
Ok so what would I need for wings and engines

@Mastergamer117 That's because removing that dead weight moves the center of mass behind the center of lift. If you want it to go faster, look into modded engines (and wings). I know you can't mod on iOS, but people have uploaded modded part kits. If you can't find one that suits you, I can upload one.

@SledDriver
Try flying it without the dead weight in the two front fuselage pieces, it won't fly that way, I want it to be lighter and faster

@goboygo1 Yeah, that's included in "Add two small elevator control surfaces." He can either add a tail and add elevators there, or add canards at the front. Either way he'll need to change the mass distribution to make sure the center of mass stays ahead of the center of lift.

@SledDriver you could also just put some horizontal stabs on the front...

@Mastergamer117 Sure, I can fix anything (in SP). The simplest fix would be nothing at all. You can use trim to make it fly level.

Another way to make it fly level without having to adjust trim would be to move the engines lower. That will cause a nose-up tendency which, if correctly adjusted, will cancel out the nose-down tendency. The only problem with this method is that this will only work at a given thrust level. At lower thrust, the plane will pitch down, and at higher thrust, it will pitch up.

The best way is to use a combination of both approaches, i.e., set the engines at a height so that the plane flies level at default thrust, then use trim to adjust attitude for other levels of thrust.

It's not a good idea to use trim on large control surfaces, as it becomes too sensitive. Add two small elevator control surfaces, and enable trim only on those.

@SledDriver
Ya but if you take out the dead weight it's too light, that's what I wanted to know if you could fix

@Mastergamer117 Do you mean correcting the nose-down tendency?

It flies already well

@SledDriver
Do you think you can fix this