It’s an unglamorous topic, but a genuinely high proportion of landing gear problems trace back to fasteners rather than the gear itself, so it’s worth a post of its own.
Over-tightening is at least as common a problem as under-tightening. Carbon fibre mounting plates and gear legs can crack under excessive clamping force, particularly around bolt holes, well before the bolt itself reaches its rated torque. “Tight” doesn’t mean “as tight as you can physically make it” — a firm, secure tightness by feel, with a drop of thread-lock for security, beats over-torquing every time.
Thread-lock matters more on vibration-heavy setups. Petrol twins in particular (see Day 13) generate enough sustained vibration to walk fasteners loose over a season, even ones that were properly tightened at the start. A medium-strength thread-lock (rather than a permanent, high-strength grade you can’t remove later) is the right choice for most gear-mounting applications.
Check, don’t assume. A fastener that was correctly torqued at initial fitting isn’t guaranteed to still be correctly torqued three months and a dozen flights later. Building a quick fastener check into your regular pre-season and post-hard-landing routine (see Day 4 and Day 9) catches loosening before it becomes a genuine failure.
Match the fastener to the job, not just to whatever’s in the spares box. Landing gear mounting bolts see cyclic shock loading, which is a different demand to a purely static fitting — using an appropriately rated fastener, rather than the nearest bolt that happens to fit the hole, is worth the extra five minutes of checking.
It’s not the most exciting maintenance topic, but it’s one of the highest-value ones — most fastener checks take moments and catch problems while they’re still easy and cheap to fix.
You can browse our 26-35cc Carbon Fibre Undercarriage for Petrol / Gas / Nitro models. to see this in practice.