What I have found with the newer OS engines, particularley the AX range is the metal alloy they are made of is very lightweight but not strong.
Icrashed my Showtime 50, with an OS 55ax in it, from aprox 6 feet above the ground, flying medium to slow speed and the engine just shattered when it hit the tarmac.
I have never in 35 years of crashing models seen an engine so destroyed. It was like it had been dipped in liquid nitrogen and hit with a hammer.
The only reusable parts were the front bearing and the 'glow plug.
All my older engines no matter what make survive being crashed remarkably well.
Only my YS110 have I had to replace a cranshaft on, but that was after 6 years of running, very high hours, and it had hit the deck a couple of times over the years.

The OS fourstrokes as well, if mounted inverted and you do a wheels up landing, the rocker cover and rockers just shear off, whereas before the rocker cover would scrape or just crack.

Isuppose the moral of the story is , donnt crash, but where is the fun in that?
The price of progress.

Darryl