Acet Posted February 23, 2015 Share Posted February 23, 2015 All the suggestions I've seen so far seem crazily over engineered. Either that or I have an unhealthy obsession with boosters.My own mid-size lifter base (20-30 ton payload to LKO) is basically a Skipper engine with an orange tank on top, surrounded by a ring of 8x S1 SRB-KD25k, in 2 groups of 4. The boosters have their trust limits set so that one group of 4 finishes (and is decoupled) earlier, then the 2nd group decouples, leaving only the main Skipper engine. Also, I make sure than the total thrust of the lower stages gives a start TWR of about 1.6 so that it climbs at close to the limit velocity and doesn't waste too much dV to either gravity or drag.The thing was designed for career mode, so the core (Skipper + orange tank) has its own probe core, parachutes and a little bit of extra fuel (for deorbiting), so that it can be recovered. Of a cost of around 70k, I get back 33k (rough numbers: I'm not home atm, so I can't check).Interestingly enough, putting a Mainsail in it actually REDUCES its range due to the extra 3t of weight (all the way to LKO) that the Mainsail has over the Skipper, while the extra thrust of the Mainsail ends up lost in drag in the lower atmosphere.Please note that the thing is a bit of a derivative of asparagus staging (minus the cross-fuel part) but with boosters that are staggered to empty and get dropped in groups, so it might not full fill your keep-assembly-simple requirement.During my previous career run in an older version I did a lot of asparagus staging, simply because if you're trying to, for example, put 80 tons in LKO orbit, there is no other way of doing it. However this time around I'm trying to minimise costs, which is really all about using boosters in the lower atmosphere to take as much liquid fuel dV (typically connected to engines with better ISP in vacuum) as high as possible before using it, tuning ascent speed to be close to limit velocity and (if you have the patience to do so), adding a layer of boosters for the extra thrust to get up to the limit velocity (of around 100m/s) ASAP during the first 1000m. Link to comment Share on other sites More sharing options...
Jouni Posted February 23, 2015 Share Posted February 23, 2015 All the suggestions I've seen so far seem crazily over engineered. Either that or I have an unhealthy obsession with boosters.This thread dates back to July 2013, when the big SRB didn't exist, Skippers and Mainsails were worse lifter engines than LV-T30s and LV-T45s, and sandbox was the only game mode available. Link to comment Share on other sites More sharing options...
Pecan Posted February 23, 2015 Share Posted February 23, 2015 See my new thread 'Lifters, light, non-heavy, mainly-SRB and pancake, a method'Very bad form to necro-post in a thread that's nearly two years old just to advertise your new one, but you could at least provide a link rather than just the title! Link to comment Share on other sites More sharing options...
sal_vager Posted February 23, 2015 Share Posted February 23, 2015 Yikes, this is old, please make a new thread instead and link to old threads next time Link to comment Share on other sites More sharing options...
Recommended Posts