Jet Engine Tweaks

[Jimbimbibble]

Hi everyone. Since the latest update the jet engines have become wonky to say the least, especially the turbojet. A plane I built with 2 turbojets that would have been fast (but reasonable) in FAR now burns itself up and accelerates at 6-7g when it hits its powerband. So, my question is, has anyone experimented with tweaking the thrust curve of the jet engines to make them more reasonable?

[Geschosskopf]

Why not just use 1 engine?

[BoomShroom]

Full throttle isn't a good idea for turbo-bearing planes that expect to stay in the atmo for extended periods, lest they disintegrate. This goes for stock and FAR, so you're better off letting up on the throttle a bit in the powerband.

[Jimbimbibble]

I know that I can use the stock engine settings to get to orbit, but I'm just not satisfied with the way the devs tuned them. I'd rather they behave in a more sane and realistic way than have to pull up at 60 degrees to prevent disintegration. I'm no expert with float curves so I'm hoping someone who is may have developed a better cfg for the engines.

[Pairs]

I've noticed the same thing with my SSTOs. In 1.0 I just take a steeper ascent profile and a higher TWR. Moar speed!

[Streetwind]

I suspect that the engines have more relative thrust than in previous versions because Squad accounted for larger planes this time around. The engines were never rebalanced when the mk2 and mk3 revamps came in, and both of these resulted in people being able to build larger planes. Squad probably want you to be able to get big mk3 hunks to their destination without excessive engine spam.

Also, keep in mind that the turbojet is not a turbojet anymore. It's now an airturbo-ramjet, which is something else entirely (namely a full bypass turbine firing directly into a ram combustion chamber). It's always been behaving more like one of these than a classical turbojet (a basic jet engine behaves like a classical turbojet); Squad merely made it "official" with 1.0. And decided to emphasize the behavior a bit more while they were at it

The problem with a normal ramjet is that it doesn't work at all unless you have a certain minimum airspeed. A turboramjet gets around this by pointing a turbine at it, thereby making the ramjet feel like it has air rushing through it at all times. This is the only reason you can take off from the runway unassisted in a pure turboramjet plane at all. But, once the plane gets up to speed, the crutch of the turbine becomes unecessary and the ramjet can fully ignite under its own power. And make no mistake: ramjets are crazy powerful devices with a lot of headroom upwards. Even IRL, maintaining control is a much harder problem than producing thrust That's why we hardly ever see them in manned flight.

[Jimbimbibble]

I agree that there should be substantial increase in thrust, but 5x? The TWR of the turbo and rapier dwarf anything else in the game at peak power and that's just not right.

[Murph]

I agree that there should be substantial increase in thrust, but 5x? The TWR of the turbo and rapier dwarf anything else in the game at peak power and that's just not right.

No they don't dwarf everything else unreasonably. They have a very specific area where they deliver the high power output, and it's not unreasonable. Needing to throttle back once established into supersonic cruise is a very realistic behaviour. Or, if space is the destination, you make use of the power peak to get as much speed as possible before losing combustion air. You just need to use the throttle to control them, if the peak power is causing a problem, or adjust the ascent profile to reap the benefits of the performance characteristics. The power peak is normally quite narrow and short lived, and for me it gives a very welcome, but brief boost to help me through the 20–25km climb where the power is dropping off almost entirely. More commonly for me, the problem isn't the size of the power peak, but actually holding onto the peak for long enough to get max possible speed above 25km.

[Streetwind]

Keep in mind that the "sound barrier" also plays a decent role in the perceived acceleration ability of your craft. There's a sharp increase in drag right as you go supersonic, kind of like a "wall" you run into. But accelerate past that and that drops off again, suddenly "letting you go". Combine this with the fact that you're steadily rising (thus getting less and less drag overall), and the ramjets really picking up arund that point as well, you get a very perceptible sudden acceleration burst that is a combination of many factors.