Need help with a Fusion powered Spaceplane

[LostElement]

I am using KSP Interstellar and B9 Aerospace (and a lot of other mods but they aren't relevant)

After watching many episodes of Scott Manley's Fusion powered Spaceplane, I decided to make one myself. I can't seem to make one. It won't lift, It puts out thrust but then dies when I run out of megajoules. I have a 2.5m Fusion reactor, and a 2.5m Electric generator.

However I cannot get it to sustain itself, it always runs out of energy or simply doesn't have enough lift. Can someone help me out?

[Streetwind]

This thread should probably go in Add-on Affairs...

[HoY]

Are you trying to use the same engine, that cone shaped one with the radiation warnings (I can't remember the actual name of it) that he is using in his latest spaceplanes? Or are you using the thermal turbojet?

[LostElement]

Yeah, I wasn't sure where to post this, can a moderator please move it?

[LostElement]

Are you trying to use the same engine, that cone shaped one with the radiation warnings (I can't remember the actual name of it) that he is using in his latest spaceplanes? Or are you using the thermal turbojet?

Yeah, it's the Fusion Engine. The conical shaped one. I did manage to get a rocket to work, but that was 3.75. I need a 2.5m. from there I'd mess with the wings to generate enough lift.

[HoY]

You need to install tweakscale and tweak the 3.75m fusion reactor down to 2.5m. It's pretty sneaky, and impossible to tell since they both use the same model. I spent quite a long time trying to figure out how he hid a 3.75m part in there before I tried scaling it down Also, if you want the engine/reactor/generator to clip inside the tail section the same way he did, you'll need editor extensions. Turn part clipping on, place the 2.5m generator on the node at the back of the ship, then put the reactor behind that, scale it down, then install the engine on the reactor. Now pick up the generator, hold Alt, and move it in towards the cargo bay until the second node on the generator connects to the back wall of the cargo bay. The reactor will be completely hidden and the engine will be lined up on the tail.

[LostElement]

You need to install tweakscale and tweak the 3.75m fusion reactor down to 2.5m. It's pretty sneaky, and impossible to tell since they both use the same model. I spent quite a long time trying to figure out how he hid a 3.75m part in there before I tried scaling it down Also, if you want the engine/reactor/generator to clip inside the tail section the same way he did, you'll need editor extensions. Turn part clipping on, place the 2.5m generator on the node at the back of the ship, then put the reactor behind that, scale it down, then install the engine on the reactor. Now pick up the generator, hold Alt, and move it in towards the cargo bay until the second node on the generator connects to the back wall of the cargo bay. The reactor will be completely hidden and the engine will be lined up on the tail.

Yeah, I have tried that. Unfortunately, the Megajoules get sucked up. I am going to experiment with Anti-matter.

[SciMan]

Did you make sure you are using a 2.5m thermal turbojet, and that the generator is in Direct Conversion mode? If so, also make sure the reactor is running the D-T fusion reaction, and set the thrust limiter on the turbojet to one tick less than 100%. The turbojet will be taking as much ThermalPower as it can, so running the generator in Direct Conversion mode means it will use the 20% of the reactor's power that is in charged particles instead of trying to cut in on the ThermalPower that the turbojet is using.

I'm pretty sure that will stop your MegaJoules from disappearing, the problem then becomes making sure you have precoolers on all your intakes and that you have enough intakes in the first place. You can get your Ap out of the atmosphere on just atmospheric propulsion if you do it right, so you should only need fuel for circularization.

As far as Antimatter goes, it's actually kind of hard to NOT make a SSTO with it. Even if you're not building a plane.

In other words, Anti-matter is great for spaceplanes!

I made a 2.5m 12-seater SST∞ (single stage to infinity) crew ferry spaceplane using B9's S2 fuselage and HL wings, 2m antimatter reactor, and thermal turbojet.

I also made a 1.25m 2 seat SST∞+W (single stage to infinity + warp drive) science spaceplane. Goes from the runway to Laythe's surface and back without refueling. (that was it's shakedown cruise).

4 Sabre S intakes stacked on 4 Sabre S precoolers all feeding one single 1.25m thermal turbojet powered by a 1.25m antimatter reactor + generator.

In space, it uses the warp drive to travel between the planets, and 4 (upgraded) plasma thrusters for main propulsion.

I can level off at about 25km, set the SAS, and when the engine flames out you should have an Ap of about 650km. No, not 65.0. Six Five Zero Decimal, Kilometers.

If you want to skip the "waiting 20 years to make/harvest enough antimatter to fuel anything interesting" part, I have a tip. Go to Jool! The trip out and back takes a while, but it's worth it.

9Mm (9000km) circular equatorial orbit around Jool is where you'll find the fastest antimatter collection rates that I know of.

If you can't get to Jool, 900km circular equatorial orbit around Kerbin is another hot spot, but its about 10 times weaker than the one at Jool.

I know there's antimatter around the sun, but I haven't sent a ship low enough around it to find out where the sweet spot is, and it's gravity well is generally a pain in the rear to deal with anyways.

Edited November 28, 2014 by SciMan

[LostElement]

I am not using the thermal jet at all. I am using the 3.75m Fusion engine (the conical shaped thing"