Best practices for FAR/RSS winged re-entry

[aspacecephalopod]

Hi all,

I've got a small shuttle mostly working in RSS/FAR/SMURFF right now. Orbital launch works perfectly, and suborbital flights straight up without the boosters/ET work as well. However, re-entry is proving to be really really tricky. The plane alternately wants to pitch up/down/spin on entry from 60km and orbital speeds all the way down to about 20km and 1000 m/s. I started out with a small delta and canards and moved to a larger delta without canards, and eventually got to the design in the second photo which handles well in atmosphere and can make it through re-entry, but only just and there's lots of shaking and fighting the controls from 6km/s down to about 600 m/s still. Airbrakes help but it's still fussy-SAS seems to increase wobbling but it's pretty hard to manage angle of attack without. Any tips for handling a 7.2 km/s entry with this sort of design?

 

[Laie]

It's been a while since I last did this in RSS/FAR. I don't think I ever managed to return to KSC (at least not without several retries), but IIRC reentry wasn't all that difficult.

The key point I remember was that I needed RCS for control until quite late in the entry (that was RO, not SMURFF -- you may get similar results by just adding reaction wheels). Control surfaces didn't provide much authority until I was pretty low and slow, 30km and Mach 6 or something along these lines.

[aspacecephalopod]

19 hours ago, Laie said:

It's been a while since I last did this in RSS/FAR. I don't think I ever managed to return to KSC (at least not without several retries), but IIRC reentry wasn't all that difficult.

The key point I remember was that I needed RCS for control until quite late in the entry (that was RO, not SMURFF -- you may get similar results by just adding reaction wheels). Control surfaces didn't provide much authority until I was pretty low and slow, 30km and Mach 6 or something along these lines.

Ah good to know! Thanks, will give it a try.