Slightly off-topic. There was an article in the PFA mag years ago about someone restoring a Turb. He found that the Undercarriage springs weren't strong enough to stop bottoming out in quite a "gentle hard landing." and that as a result a previous pilot had knackered the spar without realising it.
He did a lot of maths which went way past me, the bottom line being he fitted stronger springs with PFA approval to avoid further spar damage.
SND