Category: Blog

It’s easy to dismiss a few grams here and there as insignificant, but on the models where weight matters most, small savings genuinely compound.

Power-to-weight ratio is the whole game on 3D models. A model built for hovering, torque rolls, and other low-speed, high-power manoeuvres lives or dies on its power-to-weight ratio — every gram saved anywhere on the airframe is a gram the engine or motor doesn’t have to work as hard to move, which directly affects how “floaty” and controllable the model feels at low airspeed.

Landing gear is a good place to look, because it’s unsprung, extremity-mounted weight. Weight at the end of a gear leg, well away from the model’s centre of gravity, has a disproportionate effect on how the model handles gear-adjacent manoeuvres compared to the same weight saved somewhere near the CG — which is part of why carbon fibre gear (see Day 2) is such a popular first upgrade specifically for 3D-oriented models.

It’s not just the gear itself — wheels matter too (see Day 7), since wheel weight is rotating mass at the very end of the gear leg, arguably an even more sensitive location than the gear leg’s own weight.

Diminishing returns are real, though. Chasing grams on landing gear while ignoring far larger weight savings available elsewhere on the model (battery selection, unnecessary scale detailing, control horn hardware) is a common mistake — gear upgrades are worth doing, but they’re one part of an overall weight-conscious build, not a silver bullet on their own.

If you’re building or upgrading specifically for 3D or serious aerobatic flying, it’s worth thinking about landing gear weight as part of the same conversation as motor, battery, and prop selection — not a separate, purely cosmetic decision.

Take a look at our Carbon fibre undercarriage for 70 size nitro or electric models – narrow for a solid example of correctly sized gear.

Every flyer has one occasionally — a landing that’s harder than intended, whether from misjudged flare, a gust, or just an off day. What matters is what you do immediately after.

Don’t fly again without checking, even if it “felt fine.” Carbon fibre’s failure mode (see Day 2) means damage isn’t always visually obvious or immediately apparent from how the landing felt — a leg can retain enough residual strength to survive taxiing back and look fine sitting on the bench, while carrying damage that fails on the next hard landing rather than this one.

Check both legs, not just the one that looked like it took the impact. Asymmetric hard landings still transmit load through both legs via the airframe, and it’s easy to focus attention on the obviously-affected side while missing developing damage on the other.

Look specifically at the mounting area first — this is the highest-stress point on most gear designs and the most common location for hairline cracking to first appear, before it’s visible anywhere else on the leg.

Do a hand-flex test comparing both legs, similar to the fitting check in Day 5 — any noticeable difference in how the two legs flex under equal hand pressure is worth taking seriously, even without visible cracking.

When in doubt, don’t fly it. Landing gear is one of the cheaper components to replace relative to the cost of what happens if it fails on a subsequent landing — a cracked leg that lets go on touchdown risks the propeller, cowl, and potentially the whole airframe, well beyond the cost of the gear itself.

A hard landing doesn’t automatically mean replacement — plenty of hard landings are shrugged off without issue by gear that’s correctly sized and in good condition. It just means the checks above are worth five minutes before your next flight, rather than assuming everything’s fine because it looked fine going onto the ground.

For a real-world example, have a look at our 120 size profile carbon undercarriage (60-70″ models).

Carbon fibre is a genuinely robust material for storage compared to some alternatives, but a few sensible habits over the off-season will keep your gear in the same condition you packed it away in.

Avoid prolonged direct sunlight or heat sources. Carbon fibre itself is largely unaffected, but the resin matrix holding the fibres together can be more sensitive to prolonged UV and heat exposure than the fibre itself — a garage shelf out of direct window sunlight is a better long-term home than a spot that bakes in summer sun through glass.

Store gear unstressed, not under load. If gear is left bolted to a model that’s stored resting on its wheels for months, particularly on a soft surface, it’s sitting under a small constant load the entire time — not usually enough to cause visible damage, but there’s no benefit to it either. If you’re storing a model long-term, supporting it so the gear isn’t bearing weight is a sensible, low-effort precaution.

Keep it dry. Moisture ingress isn’t the concern with carbon fibre that it is with some wooden airframe components, but any bare cut edges (see Day 11) are more vulnerable than factory-finished surfaces, and a damp storage environment is never doing any RC equipment favours generally.

A pre-season check still applies even to gear that’s been “just sitting there.” Carbon fibre doesn’t degrade the way rubber or foam can over a winter, but the fastener and inspection checks from Day 4 and Day 17 are still worth doing at the start of the season — not because the gear itself will have changed, but because it’s a good moment to catch anything you might have missed at the end of last season.

Off-season storage for carbon fibre components is genuinely low-maintenance — a bit of common sense goes a long way, and there’s no special treatment or product needed to keep it in good order.

Our Carbon Fibre Undercarriage for 50cc models – suits Yak and others. is a good reference point if you’re shopping around.

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.

Main gear gets most of the attention, and understandably so, but the tail wheel does genuine work on every flight and deserves more attention than it usually gets.

It’s your primary ground steering on most taildraggers. A worn or loose tail wheel linkage doesn’t just cause a wobbly taxi — it directly affects take-off tracking and landing rollout control, which matters more on a crosswind day than most flyers give it credit for.

It takes real load on landing, particularly on a slightly tail-low touchdown or a three-point landing style — the tail wheel spring or mounting bracket is doing genuine shock-absorbing work, not just providing ground clearance.

Common failure points are small and easy to miss: a worn steering arm pivot, a spring that’s lost tension, or a mounting bracket that’s slowly working loose from vibration are all things that develop gradually and rarely announce themselves clearly until ground handling noticeably deteriorates.

A quick functional check is genuinely quick. With the model on the ground, gently push the rudder stick fully each way and watch the tail wheel respond — it should move smoothly, promptly, and return cleanly to centre with no noticeable play or delay. Any looseness, binding, or delayed response is worth investigating before it causes a ground-handling surprise.

Replacement is usually simple and inexpensive compared to most other gear-related items, which makes it one of the easiest maintenance wins available — there’s rarely a good reason to keep flying on a tail wheel assembly you already suspect is past its best.

Our Carbon Tailwheel bracket for 120 / 20cc models is a good illustration of the kind of fit and finish to look for.

Yaks are another perennial favourite, and their typically wide-stance, robust-looking gear can actually hide developing problems if you don’t know what to check for.

Check gear leg symmetry carefully. Yaks’ wide gear stance means asymmetric flex or damage on one leg can be less visually obvious than on a narrower-stance model — a side-by-side comparison of both legs, ideally with the gear off the model, is worth doing rather than relying on a quick glance.

Tailwheel assembly deserves specific attention on tailwheel Yak configurations — this is a smaller, often-overlooked component that takes a surprising amount of load during taxi and on any less-than-perfectly-smooth landing, and a worn or loose tailwheel steering linkage is a common, easily-missed cause of ground handling problems.

If your Yak runs a petrol twin, the vibration and fastener-loosening points from Day 13 apply directly — a full fastener check across gear, engine mount, and cowl fixings is worth doing as standard pre-season practice.

Inspect any scale add-on details near the gear, such as scale gear doors or fairings if fitted — these are often lighter-duty items than the structural gear itself and can work loose or crack without it being obvious the underlying gear is fine.

Test-fit and function-check retracts if your Yak is retract-equipped, well before your first flight of the season rather than discovering an issue on the day — a full cycle test on the bench, checking clean, positive movement with no binding, catches most retract problems while they’re still a bench job rather than a field problem.

As with the Extra, a Yak’s typically demanding flying style means a proper seasonal check is time well spent rather than an optional extra.

Take a look at our Carbon Fibre Undercarriage for 80cc models – suits Yak and others. for a solid example of correctly sized gear.

The Extra family remains one of the most popular scale aerobatic subjects out there, and a proper pre-season check pays off given how hard these models tend to get flown.

Landing gear first. Extras see some of the hardest, most repeated landing loads of any common scale subject, thanks to their aerobatic flying style — check both legs for the stress signs covered in Day 4, paying particular attention to the mounting area, which takes the most repeated flex over a season of hard 3D and aerobatic landings.

Wheel pants, if fitted, are worth a specific check on Extras given how tightly they’re often fitted for scale accuracy — a season of vibration and hard landings can work pant mounting wire loose even when everything looked fine at the end of last season.

Engine mount and firewall, particularly on the larger petrol-powered 260/300 variants, take significant vibration over a season — a visual check for any hairline cracking around mounting bolts is worth two minutes before your first flight.

Control surface hinges and linkages on an Extra see more full-deflection cycling than most sport models, given how the type is typically flown — a full-range check by hand, feeling for any play or binding, catches wear before it becomes a control surface departing mid-manoeuvre.

If your Extra has sat for the winter, a full re-torque of every accessible fastener — gear, engine mount, control horns — is worth doing as standard practice rather than assuming everything’s still as tight as when you packed it away, particularly with a model that flies as demandingly as this one typically does.

A thorough pre-season check on an Extra usually takes under an hour, and given how hard these models are typically flown, it’s an hour well spent.

For a real-world example, have a look at our EXTRA 300 90 size nitro or electric Carbon Fibre Undercarriage.

Moving from glow to petrol (or the reverse) is about more than just the engine — it changes the whole weight and vibration profile of the model, and that has knock-on effects for landing gear that are easy to overlook.

Petrol engines are generally heavier for a given displacement than an equivalent glow engine, and that extra weight sits right up at the nose — which shifts the model’s all-up weight and often its centre of gravity, both of which affect how hard the gear works on every landing, not just take-off roll.

Vibration characteristics differ too. Petrol twins in particular can have a different vibration signature to a comparable glow four-stroke, and while that mostly affects things like fuel tank mounting and radio gear, it’s also a contributing factor to fastener loosening over time — including the bolts holding your landing gear on, which is one more reason the torque checks mentioned in Day 5 are worth doing as routine maintenance, not just at initial fitting.

If you’re converting an existing glow model to petrol, don’t assume the original landing gear rating still applies once you’ve added engine, ignition, and fuel system weight. It’s worth recalculating your new all-up weight and checking it against your gear’s rated range (see Day 1) rather than assuming the original gear specification still has headroom.

The reverse conversion (petrol to glow) is less commonly an issue, since you’re generally removing weight rather than adding it — but it’s still worth a sanity check against your gear’s original design weight, particularly if you’re also changing fuel tank size or battery specification as part of the conversion.

None of this means a conversion is complicated — it just means treating the gear as part of the weight-and-balance conversation, not a fixed item you carry over unchanged.

Our CRRC GF40i Kit engine. is a good reference point if you’re shopping around.

If you’re moving into petrol power for the first time, or upgrading an ageing points-based ignition, RCEXL systems are one of the most widely trusted names in the RC petrol world, and it’s worth understanding the basics before you buy.

What an ignition system actually does. Unlike glow engines, which rely on a heated glow plug element to sustain combustion, petrol engines need a proper spark, generated and timed electronically. The ignition module takes power from an onboard battery, generates the spark at the correct moment in the engine cycle, and does so reliably at whatever RPM range your engine runs through.

CDI vs other systems. RCEXL’s CDI (Capacitor Discharge Ignition) units are popular because they give a strong, consistent spark across a wide RPM range with minimal power draw, which matters when you’re running everything off a small onboard battery pack rather than a full-scale vehicle electrical system.

Single vs dual ignition. Single-cylinder engines need one ignition module; twin-cylinder engines need a matched pair, generally timed and wired together as a set rather than mixed from different batches — if you’re replacing one half of a twin setup, it’s worth replacing both to keep timing and spark characteristics matched.

Battery considerations. Ignition systems are sensitive to voltage — running one on a tired or marginal battery is a common (and entirely avoidable) cause of rough running or hard starting that gets wrongly blamed on the ignition unit itself. A dedicated, well-maintained ignition battery, checked before every flying session, solves more “engine problems” than people expect.

If you’re specifying a system for a new petrol build, matching the ignition to your engine’s exact cylinder count and displacement bracket is the main thing to get right — beyond that, installation is generally straightforward for anyone comfortable with basic RC wiring.

You can browse our RCEXL Safety Kill Switch 2.0 to see this in practice.

Not every fuselage matches a standard gear width exactly, and that’s more common than you’d think — even within a single “size class” of model, mounting widths vary between manufacturers and even between different production runs of the same kit.

The good news is that carbon fibre undercarriages are generally straightforward to adapt in width, provided you approach it methodically. Many two-part gear designs are specifically made this way — manufacturers intend for the centre section to be trimmed or a section removed, then the two halves bolted back together at a narrower span, which is a well-established and structurally sound method rather than a workaround.

A few practical points if you’re trimming gear to fit:

Mark your cut line carefully and double-check the measurement twice before cutting once — carbon fibre offcuts aren’t reusable if you get it wrong.

Use a fine-toothed blade suited to composite materials, and always cut with adequate dust extraction or outdoors with a mask — carbon fibre dust is an irritant you don’t want to breathe or get in your eyes.

Deburr and lightly seal any freshly cut edge, since a bare cut edge is more vulnerable to moisture ingress and fibre fraying at the exposed layers than the factory-finished parts of the leg.

Re-drill mounting holes rather than trying to reuse factory-positioned holes that no longer line up after trimming — it’s a five-minute job and avoids putting unnecessary stress on a hole that’s now in the wrong place relative to the new span.

If you’re at all unsure whether your specific gear is designed to be trimmed this way, check the product description or ask before cutting — some designs are genuinely not meant to be shortened, and attempting it risks compromising the structural integrity of the leg.

Our EXTRA 300 100CC Carbon Fibre undercarriage is a good illustration of the kind of fit and finish to look for.