Duna ascents in FAR

[Starman4308]

I've been throwing together my first unmanned Duna mission (6.4x Kerbin, FAR), and I'm wondering: how essential are fins? They'd help with stability on ascent, but I'm concerned they might cause strange issues during landing (for the descent, they would pull CoP in the wrong direction). And for that matter, how are your typical ascents going to be handled? I know the whole "2-5 degrees at 60-100 m/s" thing for Kerbin ascents, but I suspect Duna launches are going to have a sharper gravity turn*.

*Depending on final engine layout, I suspect I'll have a starting Duna TWR of 1.8-2.5, which further encourages sharp turns.

Edited November 27, 2014 by Starman4308
Marked as answered.

[Hodo]

With Duna treat it as if it has no atmosphere.

The atmosphere is so thin that it is really just there for affect. It wont create enough drag to slow down most aircraft, but it will be enough to create some lift at near Kerbin supersonic speeds. Last time I sent a SSTO space plane there was way back in .21 and the landing speed was close to 300m/s which is WAY to fast. I ended up just landing VTOL without to much of an issue.

[Starman4308]

Thanks for the feedback. Hopefully this all goes without a hitch, because if stuff goes kaboom, I'm not sure this career mode game will survive the financial hit. The payload ratio is making me wince: about 2.1 tonnes of science payload, which will probably in the end require 1000+ tonnes of booster.

[KerikBalm]

Assuming you pop 'chutes (and in general, you should), the fins will be insignificant in comparison during descent.

In general, to be mass optimal, 1 chute is sufficient. If you have to arrest 20 m/s just before touchdown, adding another chute will only bring that down to about 15 m/s... but the added weight will cost you more than the 5 m/s you "save" during landing.

Of course, enough chutes to do a completely unpowered landing does simplify the landing a lot.