CrashnBurn

This mass damper design will work now with the new larger parts in .16 if you use my part.cfg edit for the decouplers.

Kind words are always much appreciated, thanks. Glad you liked my little edit.

I did a few calculations and decided the new, large decouplers needed some beefing up. This is a simple .cfg file edit that increases the strength to what it would be just given the parts volume and diameter and based on the strength of the old, small decoupler as a reference. Even with this tweak, you can still knock off an engine or tank if you don\'t design it properly, but you shouldn\'t need to truss the couplers anymore. As a side benefit, my rockets seem to wobble much less. These new config\'s are 8 times stronger than the original, which is far less than the 10x mass increase would suggest, but I think it\'s a fair balance. EnragedPlatypus cleared up where the files go, I forgot to say what folders. The first file is the large TR-19A stack Decoupler .cfg The second file is the large TT-38K radial decoupler .cfg Don\'t mix them up.

Fear my (NOT) 1337 text-editing skilz. : It wasn\'t much of an effort to do, but I\'m happy it takes a bit of frustration out of the VAB for some of you. I resisted the urge to make them stack, it would look pretty bad.

Oh, I thought we were supposed to blow up Kerbals.....I\'ve been doing it wrong all along? Seriously, I\'d love to see this mod .16 compatible. I new got around to trying it in .15.2.

Having to play with the aerospike to get it to connect was an annoyance, so I fixed it. Just a .cfg hack, but it resolves the issue. The file (parts.cfg) resolves the top attach issue. edit: I saw a forum request for a bottom attach option so I added that file also (this file is named parts.cfg.txt, just remove the ".txt" from the name before using it) The spike nests nicely hidden inside a 1m stock decoupler. I take no credit for the parts, I only edited the parts.cfg files. Figured I'd share...

Sorry Chillayy. I didn\'t mean to confuse you. I start from KSC and go into a circular orbit around Kerbin. I transfer burn to the Mun and go into Munar orbit (usually about 15-30 Km circular above the Mun surface) Then I do a de-orbit burn to land on the Mun. When leaving the Mun for Kerbin, I launch into Munar orbit (about 5Km) Then I transfer back to Kerbin\'s SOI I Orbit Kerbin Then I do a de-orbit burn to land on Kerbin.

I agree, I think a Mun landing is a bit more difficult. I usually go into orbit around the Mun, then burn for landing. To return to Kerbin I go into a 5Km orbit around the Mun, then burn for home. Circular orbits make it easier but aren\'t 100% necessary.

I agree that the new couplers are far too weak, but you can get a payload to the Mun with them, the problem is that you can\'t do it relying on Mechjeb, at least not alone. You have to experiment with each booster design and see where is wobbles and breaks and throttle down during those times. Keep the G\'s below 2. The new parts take some of the fun out of the game unless you love to micromanage the launch. I can manually fly the new parts to orbit with some luck (the rockets still randomly explode about 25% of the time) and I can also get them to orbit if I turn off Mechjeb throttle and/or stage control at specific times of high stress on the booster. But it\'s a pain in the butt. Some new guidelines to try that worked for me: 1.) No more than 3 large tanks stacked 2.) Keep the rocket short (tall rockets with the new parts wobble and disintegrate) I put my second stage in the middle of my first stage instead of on top of it. Then brace the first stages together (see my how-to on mass damping for some ideas) 3.) Place your control surfaces close/directly over to the radial decouplers to avoid torque on the decouplers from control inputs. 4.) Place the radial decouplers near the middle of the stack height. Here is a pic of my Mun lander and the Booster that got it there, for reference. It uses the center stage as a mass damper, but still wobbles a bit due to the instability of the new parts. The same design is completely stable with old parts. The center stage is held in place by only two of the new large radial decouplers with the two outer tanks connected together at the bottom with struts that pass by the narrow point of the center stage engine, allowing the center stack to swing freely on the radial decouplers.

Shortly After landing my first rover on the Mun with my new Rover Delivery System (RDS), I landed a second ship very close by, to become the start of my Mun base. Unfortunately, while driving near the landed RDS I saw it start to wobble and twist. I watched as it tore itself apart and fell over. I don\'t know why or what happened, but rather than worry about it, I decided to mount a rescue mission to recover the crew. Because the capsule was partially buried, I needed some heavy equipment to dig out Jeb and his crew. Unfortunately this is as far as I can go, since v.16 and EVA isn\'t available yet, but it was fun.

Hi Khrissette, yep, you\'re right. I didn\'t know if it would work in the KSP game physics, but apparently it does. Using the second stage to damp the sway of the initial launch and climb costs very little in additional mass. It could possibly be a net improvement in total mass if less stabilizing equipment is required. Even if it didn\'t work, it\'s still quite a Kerbal solution.

Thanks Bluejayek. I like to make an entrance. I\'m still new at this, but I\'ll be sure to add to the fun, here. Seems like a great community.

After watching the wobblies on my large boosters, I decided to apply some common structural engineering principles to increase rigidity and also to stabilize the vehicle. First I designed a tension-compression structure to increase rigidity. As there is no way to pre-tension a design in KSP, I decided to use the engine thrust to create the required structural load. This worked beautifully and allowed for a much lighter design. You can watch the structure load and unload as you turn the thrust on and off. However, there was still a good bit of wobble as I got to extreme vehicle heights. So I added a mass-damper, using the observation that the struts will act like springs (you can see them change length as they load and unload). I added a long 'pendulum' mass (as tall as the vehicle), connected at the top of the Tension-Compression structure by structural pylons (little flex) and at the extreme bottom by 4 struts (lots of flex). This addition completely eliminated wobble, even when adding a lot of height and putting the control surfaces and SAS at the extreme ends of the vehicle to try and create instability. Testing with Mechjeb (to stay more consistent between flights) the design maintains consistent stability and rigidity as height increases. I stopped testing at a dozen tanks in the stack, I know, how un-Kerbal of me not to test to failure...but I think you will agree that the vehicle looks quite Kerbalesque, anyway. The craft files requires the Mechjeb plugin. The first pic and craft file are of the 12-stack tension structure without the mass damper. This gets to a 200Km circular orbit easily with plenty of gas to play around or go to the Mun. But expect a bit of wobble. Next Pic and craft file are a shorter model of the same thrust- tensioned structure using the centrally-hung second stage as a pendulum-style mass damper. Just a fast 'first try' at it, I\'m sure it can be refined, but it works well as a proof of concept.