aerobraking with control surfaces

[endl]

so ive been wondering about how to properly use these things, i cant use chutes because i have a heavy plane that while flying the chutes burn off (deadly reentry) because i cant climb fast enough/gain the speed i need to climb to avoid the heat forces. the plane itself flies fine so i dont think this scenario can be avoided.

i want to use the brake flaps that come with b9 as well as the spoiler tweakable, this leads to a few questions (using far just to be clear)

where should i place these? top/bottom/ or both sides of the wings?

should i make them take up as much free surface area as possible?

am i correct in assuming that the spoiler tweakable can be used for braking?

Edited November 17, 2014 by endl

[Prof. Endwalker]

I would suggest that you change the cockpit to an inline, and using a heat shield on the front of the plane. This may or may not work, as I have never used or may not ever use Deadly Re-entry, but using real life sources has led me to believe that my suggestion may work.

[Wanderfound]

If you're flying with FAR, no extra parts are needed. Just set a pair of control surfaces as maxed-out spoilers, and another pair as either maxed-out flaps or negative max spoilers. Like so:

Whatever you use, balance them vertically; you don't want them to be introducing any pitch up or pitch down. Make sure they're behind CoM.

They make reentry deceleration quicker and easier, but they're not actually necessary. Control your descent rate by pitch, level off just above burn-up altitude, and descend as your speed drops to keep it riding the edge of the fire. Stay at about 30,000m until you reach Mach 5, then gradually drop to 5,000m as you slow to Mach 2. Once you're there, S-turns can scrub the rest of the speed quickly.

[Wanderfound]

Also: to keep chutes intact through heating, they need to be shielded. You can achieve this by just putting them in the shadow of the heated parts (i.e. on top of the fuselage, towards the rear), or by using a parachute bay:

Regardless, you shouldn't be burning anything off during the ascent. Climb a bit faster to start with, and level off once you get above the danger zone. Heat is a function of air density as well as temperature; a lethal temp at 15,000m is often a perfectly safe temp at 30,000m.

You'd likely also benefit from DaMichel's Kerbal Flight Data mod. Amongst many other useful functions, it also allows for easy temperature monitoring:

[Alshain]

You can also do as Wanderfound suggests with the air brakes but on the tail. If have a dual tail, you just add the control surfaces not in symmetry and do the same as he suggested with the negative spoiler deflection. With careful placement you can put two control surfaces on one tail an simulate a split surface air brake like the NASA Shuttle had. The tail is the best way to ensure you don't introduce lift altering effects. I don't have a good picture but you can kind of see it here. This one has dual tail AND split control surface air brakes, you don't have to use both methods in one, if you have a dual tail, just two control surfaces in opposite directions will work.

Edited November 17, 2014 by Alshain

[endl]

as usual wonderfound and alshain have all the answers so is there ever a scenario where you want to use the surface mounted airbrakes?

[Wanderfound]

Small-winged ships where you can't spare a control surface, lifting body ships that don't have normal control surfaces; Duna flyers; etc.

Or if you just want more of 'em. If you really, really, really hate waiting to decelerate during reentry, smother the rear fuselage in the things. But, as mentioned: they're nearly always a convenience rather than a necessity.

Reentry is not that long a process if you do it right; scrub off as much speed as possible before hitting atmosphere, and don't come in so steep that you can't level out in time. Your first job during spaceplane reentry is always to level off; once you've done that and are in control of your altitude, then you can start pushing the limits. Do it right and orbit-to-runway can be done in about ten minutes, even with FAR and DRE in play.

Once you get out of the hypersonic (< Mach 5), your main threat is aerodynamic failure rather than overheating. And, thanks to FAR's new wing strength tweakable, aero failures are nowhere near as threatening as they used to be.