RAPIERs and Turbojets are amazing in 1.0.3

[O-Doc]

I was playing a lot with RAPIERs today... and I can't say I noticed anything amazing about them. The yet-again lowered thrust is annoying. Is there some magical realm of altitude and velocity where they display their wonderfulness?

In 1.0.4, at about 8km you want to be at about 400m/s and around 7-8 degrees AoA(pushing through the sound barrier at about 6km). Keep that AoA for maximum results. Assuming you don't have junk on your flier that drags and splodes, you will reach almost 1.7km/s on open cycle.

All my SSTOs got over a 5% payload fraction increase on the patch but, I had to drop in around 25% extra atmo fuel.

[Brotoro]

In 1.0.4, at about 8km you want to be at about 400m/s and around 7-8 degrees AoA(pushing through the sound barrier at about 6km). Keep that AoA for maximum results. Assuming you don't have junk on your flier that drags and splodes, you will reach almost 1.7km/s on open cycle.

All my SSTOs got over a 5% payload fraction increase on the patch but, I had to drop in around 25% extra atmo fuel.

So the plane's nose should be kept 7-8 degrees above the prograde marker on the navball? Is the actual angle of climb unimportant?

Edited June 28, 2015 by Brotoro

[rofltehcat]

In 1.0.4, at about 8km you want to be at about 400m/s and around 7-8 degrees AoA(pushing through the sound barrier at about 6km). Keep that AoA for maximum results. Assuming you don't have junk on your flier that drags and splodes, you will reach almost 1.7km/s on open cycle.

All my SSTOs got over a 5% payload fraction increase on the patch but, I had to drop in around 25% extra atmo fuel.

You can carry 5% more payload?

Everything I get into orbit has about 5% less payload and I need more fuel as well but I'm not using Rapiers.

But I agree with the new ascent profile. Doing a flat acceleration is more important now. I found the trick to be in doing it neither too steep (lower end speed) nor too flat (will never reach orbit, lose a lot of energy when pulling up to push up the apo).

So the plane's nose should be kept 7-8 degrees able the prograde marker on the navball? Is the actual angle of climb unimportant?

I think he means 7-8° above the horizon. Though that is the angle the prograde should go, not necessarily the nose (ideally the nose isn't that far above prograde to avoid drag). But I'm still testing. Sometimes it feels like I'm not going anywhere, sometimes it feels like I'll burn up.

[GoSlash27]

Interplanetary SSTOs are definitely doable again. I just burned my payload fuel during a test using the RAPIER and got a periapsis inside Eve. It was more of a radial in than a retrograde, so lots of spare DV there.

My sweet spot so far seems to be around 2 engines, 800 fuel (in wet wings and strakes), and 900 fuel/ 1100 o2 oxidizer. This yields a 32 tonne vehicle with 8 tonnes of payload.

Best,

-Slashy

[Starhawk]

Interplanetary SSTOs are definitely doable again.

That's for sure. Huge atmo changes result in a big boost for spaceplanes despite the air-breathers' ISP nerf. The SST Laythe and back thread has seen renewed hope. I wouldn't be surprised if somebody (maybe Red Iron Crown) has done it by now.

My sweet spot so far seems to be around 2 engines, 800 fuel (in wet wings and strakes), and 900 fuel/ 1100 o2 oxidizer. This yields a 32 tonne vehicle with 8 tonnes of payload.

I managed 10.6 t payload to LKO using a 33 t, 2 Rapier spaceplane for RIC's Payload Fraction Challenge. 1440 LF and 924 O2. Razer thin margins.

Happy landings!

[O-Doc]

So the plane's nose should be kept 7-8 degrees above the prograde marker on the navball? Is the actual angle of climb unimportant?

You should put on all your vertical velocity in lower atmo(always use the entire runway) and as you get up to speed, point directly into your prograde which should sit just below ten degrees above the horizon. You want the least amount of drag possible so keep pointing into prograde all the way into space. High TWR is important and your craft should want to go into trans-sonic at low altitudes which you can wash off with higher and higher AoA below 8km.

I've found the most efficient crafts have a high enough TWR for me to have to wrestle the prograde down to the horizon as I go trans-sonic. There's definitely a fine line you have to dance between maximising speed and spontaneously combusting at around 12km.

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I think he means 7-8° above the horizon. Though that is the angle the prograde should go, not necessarily the nose (ideally the nose isn't that far above prograde to avoid drag). But I'm still testing. Sometimes it feels like I'm not going anywhere, sometimes it feels like I'll burn up.

Yeah, sorry. I meant 7-8 degrees above the horizon.

[Red Iron Crown]

You should put on all your vertical velocity in lower atmo(always use the entire runway) and as you get up to speed, point directly into your prograde which should sit just below ten degrees above the horizon. You want the least amount of drag possible so keep pointing into prograde all the way into space. High TWR is important and your craft should want to go into trans-sonic at low altitudes which you can wash off with higher and higher AoA below 8km.

I've found the most efficient crafts have a high enough TWR for me to have to wrestle the prograde down to the horizon as I go trans-sonic. There's definitely a fine line you have to dance between maximising speed and spontaneously combusting at around 12km.

Most efficient in the sense of least dV to orbit or in maximizing payload fraction? I ask because my best results for payload fraction have fairly low TWR (~0.5 at standstill on the runway, or a bit less than 20t per Rapier) and stay subsonic for the climb to 12km, then trade altitude for speed to break through the sound barrier and begin climbing again. I am far from a spaceplane expert, though.

[O-Doc]

Most efficient in the sense of least dV to orbit or in maximizing payload fraction? I ask because my best results for payload fraction have fairly low TWR (~0.5 at standstill on the runway, or a bit less than 20t per Rapier) and stay subsonic for the climb to 12km, then trade altitude for speed to break through the sound barrier and begin climbing again. I am far from a spaceplane expert, though.

Good question. From what I've seen on the forums my specialist heavy lifter is more fuel efficient than most. I know Rune gets slightly better payload fractions with an approach similar to yours. But, my high TWR planes are cheaper to operate and take far less time to suborbit.

I'm over 30% payload fraction and over 50% fuel at LKO.