Nich

SSTO to the mun is a good test of piloting skills

What did you do improve the aerodynamics?

I don't see a pull stage being that feasible to launch in one go as it would be a limp noodle but here is an example of an ION pull dragger I built as a prof of concept. Only 13km dv though

I don't know what is more difficult about this challenge the 2 hour limit or the 100 parts. I think there is definite room for improvement. 65 parts 1360t 1h57m45s burn time on the pad 19,874 dv in orbit

Well making mediocre improvements made 84x75 but I really only have 23 dv to play with due to my flight path. It seems the most efficient launch is to pick up most of your horizontal velocitly as you climb slowly from 40-55km so a 55x80 is about as low as I can go. Total cost 149447 Payload cost 42567 Launcher Cost 106880 Payload 146.39 730.10/ton I thought it was the launch clamps, nose cones, and quad connectors holding me back but even if I subtract those I only get down to 680 on an impossible to build craft

Damit maccollo I have been trying to get a 3.75m to work forever but I am stuck around 740/ton Here is my attempt at a lifting body but with the extra cost/weight of lifting surfaces I cant get it below 870ish and that includes cheating and counting lifting surfaces on the payload. Seeing how well you conquered my old nemisis maybe it is possible but I am giving up

I believe that mod is called Tweek scale But most people consider it cheaty for challenges

Nice Goslash I verified all numbers and a 91x72 orbit easy as cake. It probably could have gotten 80x80 if i was paying attention

Damit I just fixed maccollos entry the increased twr on the middle stage makes gravity turns much easier just follow prop all the way 26.28t Total cost 34968 Payload 18450 lifter cost 16518 628 funds/ton

maccollo I attempted to make your first place entry and holy heck that is a tiny window to launch into. Too low and you dont make it, too high and you dont make it. Best I have been able to do is 78x71 and for some reason my rocket weights 90kg less and has 5 more dv

So I did nearly perfect gravity turns and got everything out of both configs that I could. Vehicle 1 had a TWR on the pad of 1.14 and made orbit with 12088 units of fuel to be converted to payload. Vehicle 2 was only able to get 11106 units. I forget how to convert to tons (?/9000 accounts for fuel and tankage?) if so that is 1.343t and 1.234 or a 8.833% decrease in payload. Cost of rocket 1 was 107150 cost of rocket 2 was 94150 or a 13.807% decrease edit ops forgot to add the payload which was the same for both rockets of .9t giving the 1.47 rocket even better results of only decreasing 5.11%

I missed the LFO requirement rule I like that it is a good call as the best isps are quite similar for all 3 sizes for circularization. I do feel you should be limited to 1 circularization engine. I am not opposed to 100m/s but I actually prefer the 500m/s as this feels more realistic. We are at the point where the design has pretty much been worked out. SRB first stage, efficient LFO to AP, Circularize. At this point it is about tweaking the rocket to end with 0 usable dv left. What have we learned? LFO lifter engines are generally not worth it and if they are they need to be sustainers. initial TWR of ~ 1.5 Low TWR in a mid stage is probably more efficient then flying on propagrade. Drop tanks are quite viable from a cost perspective (quasi asparagus) It appears nose cones are still worth there value although I am not sure if anyone has done nosecone less testing but has not possed it because it didn't work. I originally thought I am fine with reaction wheels in payload but then I thought of someone using a 2.5m reaction wheel in a 10t payload has a definite advantage so I am leaning more to reaction wheels have to be on the launcher or limited to 5 torque in the payload

I have no problems with 1 reaction wheel and probe core in the payload and I have never launched a payload without a reaction wheel. 2 or 3 is exploity I as stated before have no problems with a deep space engine being used on the core stage as long as non of the payload fuel is touched and the final twr > .3

current leader in the low cost challenge has a 1.45 twr http://forum.kerbalspaceprogram.com/index.php?/topic/130730-the-cheap-and-cheerful-rocket-payload-challenge-105/&do=findComment&comment=2384481 my entry which would be in second if not disqualified had 1.97 twr. If tweaked it could easily take first http://forum.kerbalspaceprogram.com/index.php?/topic/130730-the-cheap-and-cheerful-rocket-payload-challenge-105/&do=findComment&comment=2383129 You also have to remember ksp is tiny so comparing it to real world doesn't work 2400 m/s vs 7700 m/s I also though I remember hearing in ksp engines are too heavy and fuel is too light and ISPs are too low vs real world space shuttle has 345 atm 455 vac isp or something along those line that could be the cause of the discrepancy. Also in the real world engines are much more expensive. I believe the SLS just got 17 billion from congress and that has to be divided between 100ish launches to get RnD cost I will try a 1.16 twr and see if I can get it any were as cost efficient

I didn't even think of ions for a tug because you would probably need 50/100t just to get a bar minimum TWR and you cant IRU zenon gas but it would be the best final stage for this comp without a doubt Has anyone tried a SRB second stage to get cost down or are they just too heavy the first stage losses too much? I was not able to get it to work for less then 1000/ton SRBs to orbit was about 1800/ton but a lot of fun to play with no control lol

maccollo I am complimented that you stole my idea for drop tanks after I stole your idea for quad kickbacks I am all for no explosive decoupling as if feels like xploity I am also a believer that payload should arrive to orbit without any missing fuel how ever I feel my first entry should be allowed as a rhino makes sense as a thruster for a 136t transfer stage. Depending on dv requirements it is a better selection then a nuke cluster. If it was a lifter engine i.e. mamath it would be disqualified. maccollo I think you might be able to break 500 if you take your original design and move 500 dv from the lifter stage to a nuke final. First the nuke will get 500 dv for very little mass giving a greater final tonnage I was going to play around with that but ran out of time. Meithan I tried to checkout your Optimal engine charts web app and it appears the link has gone dead?

1.0.4 it would not 1.0.5 I have seen some things I did not expect

gravity losses and oberth benefits both say go faster sooner. With a TWR of 1.1 your loosing a ton of fuel to gravity and later you have to carry around that extra tankage further reducing your DV. Otherwise everyone would start with a 1 and burn until you start moving. everything I have read in real world states a max twr of 25 on unmanned craft (starting around 7) because the structure to support the craft become excessively heavy. Air friction is not a major concern Check out the challenges section they have everything from payload fraction, cost per ton, most tonage, least dv. Only time I have seen a limit is below 6km you want to be less then 600m/s i think. It was a standard rocket max height challange I believe the rocket had something like 2.5 twr at launch

Ok so here is my retry. It really sucks compared to the previous entry Did an absolutely perfect gravity turn too and it was so easy just turned to 15 degrees and turned off SAS until SRB ran out then followed prapagrade 123.38t Total Cost 130794 Payload Cost 37120 DV used out of the payload 158 759 funds/t

Well I wanted to see if the expensive engines could pay there weight and I have to say no. I was not able to break 1000/ton until I "cheated" 157 dv left before I decoupled the tanks no fuel used from the payload (I just realized I could have used 500 dv) Total cost 138260 Payload cost 58220 Payload to orbit 136.26 tons Giving 587 kerdits/ton Even if you add the cost of the engine it is still only 770/ton so nothing to be ashamed of HAHA did you enjoy your minute on top?

I think red iron crown posted something from mech jeb or another tool from a gravity turn and in it 15% was lost to gravity 1% was drag and 2% was cos losses. In reality loss counts for very little even in a straight up to 70m and then circularize. Most engines max out there dv/ton when you put it under 1 of the largest tanks that fit above it. 2 and you don't get as much dv/ton but you do get more dv per engine. Are you limited by pad weight? part count? cost? they all have different design stratagies If you want cheap solid booters cant be beat.

Made it to the Mun and Minimus and back with this 8.8 ton entry I have TAC life support so I had to hack it and give my self 70 days of supplies on EVA which messed up my electrice but with 6 panels the ion has way more then enough juice. Made it back to kerbin with 56 dv left

I cant find it atm but I made this for another challenge requiring all size 0 parts. 8.8 tons Mun and MInimus but I was missing snacks (I even use TAC life support so I wouldnt have had to hack that to give 50 days of supplies on eva kerbals) Yes my electric charge is hacked but with 6 1x6 panels the ion can run forever.

Good I am not the only one and I love the ambient music when I am doing chores

Notice it doesn't say anything about refueling or ISRU. I wonder if they have to be done in order? I would think it would be something that can SSTO Tylo and stage Eve are your biggest hurdles