Spaceplanes again - re-entry and landing

[RizzoTheRat]

I've finally manged to come up with a space plane design that can make it in to orbit.

However getting it back down again is proving a little trickier.

Is there a knack for working out where to de-orbit in order to hit the landing strip? First attempt overshot by miles, and the second attempt ran out of fuel and came down in the sea a couple of hundred km short of the runway, and annoyingly about 500m short of land, luckily I'd fitted parachutes as I was expecting landing to be a problem.

Also what's the best approach for re-entry? Nose high to let the body and wings cause lots of drag, or keep the angle of attack fairly low and rely on airbrakes?

Up to now I've always splashed capsules down in the ocean, so no need to worry too much about where I'm aiming.

[MrWalrus123]

Try to put your periapsis just below sea-level, make sure the line ends where the peninsula by the KSC is (Aka whee the land bridge used to be), and make sure you re-enter on a steep anlge

[tseitsei]

I can't aim to KSC properly but most places are flat enough to land there quite easily...

[JAD_Interplanetary]

I usually put Pe between 32-36km directly over the large peninsula across the ocean from KSC. The craft re-enters on a shallow glide, keeping AoA around 45 degrees, using mainly wings and body to bleed off speed, but also with airbrakes fully extended. The shallow glide helps to manage the re-entry heat, you bleed off a lot of speed before hitting the thickest atmosphere. Once below 30km when air-breathing jets start working again, AoA lowers and becomes more like normal flight, and then I just use airbrakes to trim my speed down to manageable. Checking the world map, my trajectory is usually either right beyond or right in front of KSC by that point. Now it's more like a normal flight, but still bleeding off speed. I only throttle up the engines if it looks like I'll severely undershoot; it's mostly gliding. I usually pass just over the tops of the mountains west of KSC if I'm on the proper course.

[viktor19]

From 80x80 orbit it was pretty straightforward for me. Burn on the opposite side of Kerbin for 38 km Pe, try to hit 70 km above the desert, try to stay above 35 km before reaching mainland (coming from the east) and compensate with small amounts of thrust if needed.

Optionally deploy airbrakes over that ridge west of KSC if needed.

Flag put right before the start of the runway also helps!

[MaverickSawyer]

I use the Trajectory Drawing plugin, and aim about 300-350km short, depending on the design and the results of the first flight of that design (I use lifting reentries, so I need that extra range.)

[DocMoriarty]

Coming from a 110x110km orbit where usually my space stations are i usually plan a burn with Pe precisely 34-36km above KSC from the opposite side of the planet. Then do a long descent around half the planet and keep plane most of the time on the prograde marker.

[Vanamonde]

How-to question moved to the how-to subforum.

[I_Killed_Jeb]

Lots of different approaches, some of which have been explained above. Most helpful, I think, is to err slightly on the long side and then aggressively scrub speed/altitude using airbrakes and a deep 45 degree dive once KSC is in sight.

Something to keep in mind is that entering like a space shuttle (high AoA with nose pointing up) will very significantly lengthen your glide trajectory from the lift, even at pretty high altitudes. Your plane looks very well lifted so I think you might be running into this a bit.

[jiminator]

so what AoA to use that burns off speed without exploding ?

[I_Killed_Jeb]

I prefer pointing prograde with full airbrakes until my craft stops heating up (I use the KER heat readout) and then go full dive (often times up to negative 35-30 degrees AoA). I pull up to glide in for a final approach that's relatively gentle. I have not had a problem with this yet.

[RizzoTheRat]

Interesting range of styles here, good point on it varying a lot depending on your lift.

I don't seem to be having any major heating problems coming in at about 20 degrees nose up from a 75-80km orbit so I'll persevere with that but aim long and dive with the airbrakes to dump height in the lower atmosphere. The shallower approach angle I can get away with the better as the less fuel I use in the deorbit burn the more I have to cruise to the runway if I get it wrong.

I think looking at some other people's designs I'm relatively low power and high lift, but I found with less wing I was having to have a really high AoA, which caused a lot of drag on the ascent. I assume 20-22km and 1000-1100m/s is a sensible target for lighting the rockets when using the Whiplash ramjets (not researched Rapiers yet).

Had a go at building a bigger one last night with 4 ramjets and 2 rockets to use as a crew shuttle, but got the weight balance wrong and one wing and engine pod broke off when it pitched up sharply during re-entry. I was surprised that the rest of the craft remained intact and the crew survived on the parachutes.

This is the first time I've had a go with planes in 1.0, they seem to behave a lot more like I'd expect than they did in the previous versions

How-to question moved to the how-to subforum.

Ooops, sorry.

[Starhawk]

so what AoA to use that burns off speed without exploding ?

This is completely dependent on the configuration of the craft.

Happy landings!