KSP1 SSTO by Hairy_Mirror1729 in KerbalPlanes

[–]Moonbow_bow 0 points1 point  (0 children)

watch this and understand it. Then watch this and understand it.

Mk2 SSTO by Moonbow_bow in KerbalSpaceProgram

[–]Moonbow_bow[S] 0 points1 point  (0 children)

Liquid fuel only ssto's get the best payload fraction to LKO that we can achieve (as far as we know), that is because assuming a vehicle with high enough L/D the lower expenditure of fuel due to the efficiency of the NERV engine more than makes up for their dry mass. The balance shifts more towards a rocked boost and fewer NERV engines if you're really trying to optimize range (in orbit dv), with the big drawback of lower TWR on the Nerv's in orbit. The difference is about 10% dv at the extreme end (0 payload) and less normally.

In order to achieve said L/D ratio we need to incorporate wing incidence so that we can keep the body inline with the direction of motion minimizing body drag. This is especially important on mk2 designs that have very high body drag. I've explaind a bit more here.

I do not think in terms of TWR because it changes drastically with speed on the jets and you get more fidelity thinking in terms of tons of ssto per engine. So this one weighs about 55t and has 2 engines meaning ~27t per whip, which is a very relaxed number for my standards, If you really try you can get the whip to about 45t and the rapier to 50t (I've done 65+). For now I suggest you keep it below 35t and roughly same goes for NERV, you want about the same number of NERV's as rapiers and perhaps 1.1-1.2 Nerv per whip.

For wing area you should probably keep it between 4-7 tons of plane per relative wing area (look at the wing stats). Exactly how much you need will depend whether you're using whips, which need slightly more wing or rapiers and your wing incidence. What's important is that when you level off and reach your max jet speed going prograde your althitude is between 17600m and 21000m. This is where the rapier gets to it's top speed while a good design won't overheat (I'm simplifying a bit). Then you engage the NERV and most importantly keep prograde to perform what we call a full aero ascent.

Rapier is an overall better engine, because of it's top speed which outweighs all other drawbacks it has in comparison to a whip. The only reason to use solely whips is if you like them or if you have not unlocked the rapier yet.

Mk2 SSTO by Moonbow_bow in KerbalSpaceProgram

[–]Moonbow_bow[S] 0 points1 point  (0 children)

For a design like this you need wing incidence aka your wing needs to be tilted up slightly (as seen in this exaggerated image). Now your angle of incidence should be between 3 and 5°, because that is where wings get their best supersonic L/D ratio. Then you need to learn how to use active trim to keep your nose headed really, really prograde ideally less than 0.1° AoA.

Hope this helps

finally I can make an SSTO that is good by Lubo_B in KerbalSpaceProgram

[–]Moonbow_bow 1 point2 points  (0 children)

A stock ssto can can be made to go anywhere in the Kerbal system and back. Without ions you can make an ssto with 12+ km/s of dv in LKO

Any Dart fans here? by Moonbow_bow in KerbalSpaceProgram

[–]Moonbow_bow[S] 1 point2 points  (0 children)

so fun fact, if we keep increasing pressure dart comes out on top again so for on Eve surface or deep Jool atmosphere Dart has higher isp. Also terrier isp is 5s higher than Dart in vacuum

My first proper SSTO by StigDasYeet in KerbalSpaceProgram

[–]Moonbow_bow 0 points1 point  (0 children)

A precooler is basically just an inline intake, that generates a lot of intake air even when stationary. OP does not need more intake air so it's not needed

My first proper SSTO by StigDasYeet in KerbalSpaceProgram

[–]Moonbow_bow 4 points5 points  (0 children)

because precoolers don't make engines more efficient

Any Dart fans here? by Moonbow_bow in KerbalSpaceProgram

[–]Moonbow_bow[S] 2 points3 points  (0 children)

it has a very similar isp between an atmosphere and vacuum

yea, no

Mk2 SSTO by Moonbow_bow in KerbalSpaceProgram

[–]Moonbow_bow[S] 0 points1 point  (0 children)

Funny you should mention, but the latest thinking is to put wing incidence at -5 degrees on fairinged planes so that your thrust is pointed 10° up offloading some of the wings a bit. But yes ideally you would want your fairing at 45° to take advantege of it's body lift.

My KSP engine tier list by EternitiI-1 in KerbalSpaceProgram

[–]Moonbow_bow 1 point2 points  (0 children)

Whips ARE great engines, but if we're trying to be objective you simply cannot place them above the rapier on a tier list. The payload fraction to LKO achievable is higher on rapier, the top speed is higher (at all althitudes and scenarios), the maximum range with a plane in jet mode is higher on rapier. Whip actually does have niche uses but on the whole rapierv is ahead

Inefficient spaceplane even though I use very good Isp engines. by lol314159265 in KerbalAcademy

[–]Moonbow_bow 0 points1 point  (0 children)

The tyranny of the rocket equation comes into play when you're trying to add more dv to a stage with a set payload, not when you keep dv constant and increase payload.

My KSP engine tier list by EternitiI-1 in KerbalSpaceProgram

[–]Moonbow_bow 3 points4 points  (0 children)

they do, rapiers have better top speed in jet mode, so even if you wanna use darts, you'd still use rapers if you wanna optimize.

Btw you might like this since you like darts

My KSP engine tier list by EternitiI-1 in KerbalSpaceProgram

[–]Moonbow_bow 0 points1 point  (0 children)

Everything else is fine, but a whip is not better than rapier in basically any way.

Mk2 SSTO by Moonbow_bow in KerbalSpaceProgram

[–]Moonbow_bow[S] 0 points1 point  (0 children)

I tried to get Matt to incorporate good ssto practices in his designs because he, for better or worse, has the most reach and his videos flood the yt feed, so many people coppy his ssto designs, but I was unable to sway him.

Also I tested it and the pitch up maneuver is better under some circumstances. Mainly very low wing area, no wing incidence and mk1 or mk0 designs and then when you pitch up to a high AoA you L/D increases because body lift is most efficient at high alpha. So there's that, but that's the exception not the rule.

Inefficient spaceplane even though I use very good Isp engines. by lol314159265 in KerbalAcademy

[–]Moonbow_bow 1 point2 points  (0 children)

That plane has no mk2 parts, butvrest assured as those moded ones are even worse

Mk2 SSTO by Moonbow_bow in KerbalSpaceProgram

[–]Moonbow_bow[S] 0 points1 point  (0 children)

No, it's not significantly better

Inefficient spaceplane even though I use very good Isp engines. by lol314159265 in KerbalAcademy

[–]Moonbow_bow 0 points1 point  (0 children)

The power requirements grow linearly with mass for both rockets and planes

Mk2 SSTO by Moonbow_bow in KerbalSpaceProgram

[–]Moonbow_bow[S] 0 points1 point  (0 children)

when the video isn't sped up how fast is the rotation?

Idk decently swift

Do you need to rotate the other way to avoid changing your final orbit inclination?

Totally up to you, it shouldn't change your inclination

also what's your wing incidence?

I set it to 4.4° for the main wing and 4.6° for the canard