frog

Fellow Kerbonauts! In all my (presently) 180hrs playing KSP, I have never found a use for the different struts, adaptors, etc. They all seem too small, and with the exception of rovers, seem to provide no real benefit to my crafts. Whenever I watch videos, I never see (or notice?) any of these parts being used. I've scanned the forums, wiki, and the greater internet but to no avail. However, both in vanilla and in the BTSM mod, these parts are unlocked fairly early, which makes me think they must offer some advantage that I'm not aware of. What are your feelings on these parts? Do you use them often or ever, and if so, in what ways? Also, is there an in-game way to resize them that I've been too dumb to see? I encourage photos!

First off, I have to say I'm impressed that that worked out so well. I try reaching Duna using all sorts of calculations and junk and it seems to be way more difficult than you just winging it. So props on that! That said, I find the video is very short on crucial information. Two of the main challenges of getting to Duna are building a craft that packs enough dV and launching at the right window--precisely the two things that you spend the least amount of time talking about. If you are not going to discuss craft-building in any depth, I would suggest not bothering to show the VAB at all. In addition, just by watching your video, I don't think anyone would be able to accurately gauge an appropriate phase angle for the ejection burn; it is very unclear where Duna is in relation to Kerbin while watching the video. It is only shown for a split second, and at an odd angle. Consider giving a rough estimate (45 degrees) to help viewers better understand the planetary alignment.

Thanks for the insight, xcorps and necrobones! I did a little experimenting to see how much efficiency can be won by making use of the Oberth effect. It was done in two parts. These experiments were done manually and without the help of MechJeb, so values aren't perfect but clear enough. First, I made a circular orbit at 180km around Kerbin. From any point in this orbit, it took appx 790m/s of delta-V to reach the elevation of the Mun. I then shrunk the orbit to an elliptical with the apoapsis at 180km and the periapsis at 70km--this burn cost appx 82m/s. In this new orbit, burning prograde at the periapsis to reach Mun elevation required appx 778m/s of delta-V, while burning from the apoapsis now cost 870m/s. Then, I made a circular orbit at 10Mkm. To reach Minmus elevation from here, it cost 159m/s of delta-V. Shrinking my orbit again to an elliptical with the periapsis at 70km required 377m/s. From the new periapsis, burning to Minmus took 74m/s. What we see is: the Oberth effect is NOT effective enough to warrant shrinking an orbit. If you've already spent the delta-V to make an orbit, trying to increase your speed by shrinking your periapsis is very inefficient. Secondly, I applied this to escape trajectories, to see if shrinking your orbit would have a different result. However, the results were similar. In a circular 10Mkm orbit, escape was reached with 191.6m/s of delta-V. After shrinking the periapsis to 70km (as above--377m/s), the escape delta-V rung in at 84.4m/s, in total over twice the fuel cost. Ultimately, it seems the Oberth effect is only useful if you don't have to change your orbit to make use of it. I suppose that means: the lowest possible orbit after launch is the best one. Might this also indicate the if your initial orbit is elliptical, depending on the ejection angle it might be more efficient to burn from a non-apsis rather than first circularizing the orbit? Does anyone see any holes in my methods or in my conclusions, or have any evidence that shows the Oberth effect being more efficient? PS Hello Kerbal forums!