Do you hate lag? Don't lie. I know you do. Are you a mobile user who hates lag? You can use low physics to reduce lag. I switched from high to low a week and a half ago and I have had a problem with lag only once since then. The bad thing about low physics is that some pieces do not perform well on it. Detatchers and pylons bend, rotators have poor connections under high stress, and wings snap off like they're made of butter. I updated @Vikdesigns's Sarplaninec so it could be used on low physics because the missiles were as floppy as a wet piece of bread. Now I have updated @BaconAndEggs96's F-35B Lightning II to use on low physics as well. First of all, if you use high physics, go download the original instead. Get outta here. If you have tried and failed to fly the original, I have some pointers:
-use high physics (if you want lag later on when you download something huge)
-fly at 37% throttle
-don't turn off the RCNs

If you exceed 37% on the original on low physics, the primary wings will break off and you will crash. In this update, they will still break off, but BAM! Some Emergency Wings™ are right there to take their place. Press 2 to release the VTOL engines. Throttle up to 36-38% slowly. Any more or any faster and it will flip over backwards because the VTOL nozzles in the front spool up faster than the large jet engine in the back. Use pitch and roll to balance out and when you are high enough, VTOL up to start moving forward. Press 1 to put up the landing gear. I also added two missiles to make the 15-part addition unwritten rule. Use 3 and 4 to shoot them. Use 5 and 6 to drop the detatchers they were on. After you shoot them, obviously.

I do not like to switch back and forth between physics settings. It wastes time and is too complicated. Low physics makes parts not work right, but high physics creates a lot of unnecessary lag. Medium is for losers. I modify planes for low physics because I know there are others somewhere who feel the same as me about their physics settings, and I care enough about the plane to take the time to work on it. This may be less realistic, but I can fly it and you can too. Enjoy.