After I explained to Maltz what you'd said about flipping and tipping, he said that we should say that qaw' means "tip over" and qaw'moH means "tip over, knock over, knock down."

You'd use qaw' if the object [i.e. "thing", not grammatical object] tipped over on its own accord or seemingly on its own accord (even if there is a known cause). If you lose your balance, you may qaw' (in English, in this situation, you'd probably say "fall" or "fall down" or "fall over" rather than "tip over," but it's the same sort of action). Without remediation, the Leaning Tower of Pisa might qaw' one day. A few years ago, we had an earthquake here. I wasn't home at the time, so I didn't know what kind of damage (if any) to expect when I got home. It turns out, almost everything was fine! Only one little statue qaw'ed.

So what the rebels do is qaw'moH the cars (like some folks are doing in the US right now).

For flip all the way over, it's a little more complicated.

yoy means "be upside-down"

yoymoH is fine for "flip (all the way) over"

But if something flipped all the way over on its own accord or seemingly on its own accord (parallel to qaw'), that would be tach "turn over." You'd be more likely to use tachmoH than yoymoH when moving someone from a prone to a supine position. And you'd be more likely to use yoymoH than tachmoH when flipping over hamburgers or pancakes. On the other hand, either would be fine for flipping over cards, with yoymoH implying a quicker or crisper action. I can imagine in a Kalibo* show, there might be an opportunity to use tach without the -moH!

* [Kalibo is a stage magician which Okrand met at qepHom 2016]

(message to Lieven L. Litaer of June 4, 2020, archived on qepHom.de)