Landing Gear Repairs: Keeping Your Model Ground-Ready

Landing gear is one of the hardest-working parts of any RC airplane. It absorbs every takeoff, every landing, and every bump across the runway. Whether your airplane flies from pavement or a grass field, the landing gear takes a tremendous amount of abuse.

Unfortunately, it is also one of the most overlooked parts of an airplane during routine maintenance.

Many pilots only pay attention to the landing gear after something bends, breaks, or falls off. A little preventive maintenance, however, can prevent many repairs and save you from ending an otherwise great day at the flying field.

Landing Gear Takes More Abuse Than You Think

Every landing places stress on the landing gear.

Even a smooth landing transfers energy through the wheels, struts, mounting blocks, and fuselage. Add an uneven runway, a crosswind, or a slightly harder-than-planned touchdown, and those forces increase dramatically.

Over time, even perfect landings can loosen mounting screws, weaken plywood gear plates, bend wire gear, or fatigue aluminum landing gear.

That is why experienced pilots include the landing gear in every preflight inspection.

Start With the Wheels

The wheels may seem simple, but they deserve a close look before flying.

Check for:

• Cracked plastic hubs
• Loose wheel collars
• Missing wheel retainers
• Worn foam or rubber tires
• Bent axles
• Excessive wobble

Spin each wheel by hand.

The wheel should rotate freely without rubbing against the landing gear or axle hardware.

If it does not spin smoothly, investigate before flying.

Inspect the Axles

Axles are surprisingly easy to bend, especially after a rough landing or a nose-over.

A slightly bent axle may not seem like a problem, but it can increase rolling resistance and place additional stress on the landing gear.

If the airplane pulls to one side during takeoff, a bent axle may be the cause.

Replace damaged axles rather than trying to straighten them repeatedly. Metal that has been bent several times becomes weaker each time.

Check Wire Landing Gear

Many trainer and sport airplanes use wire landing gear.

Wire gear is remarkably durable, but repeated hard landings can slowly change its shape.

Inspect for:

• Bent wire
• Cracks near bends
• Rust
• Loose mounting straps
• Broken solder joints

If the gear has been bent slightly, it can often be carefully straightened.

However, repeated bending weakens the metal. If cracks begin to appear, replacement is the safest option.

Aluminum Landing Gear

Many larger airplanes use aluminum landing gear because it is lightweight and strong.

Look for:

• Hairline cracks
• Twisted gear legs
• Deep scratches
• Bent mounting surfaces
• Loose mounting bolts

Avoid repeatedly bending aluminum back into shape.

Unlike steel, aluminum becomes more brittle after repeated bending and may eventually fail without much warning.

Carbon Fiber Landing Gear

Carbon fiber gear is extremely stiff and lightweight.

Instead of bending, it usually cracks.

Inspect carefully around:

• Mounting holes
• Layer edges
• Stress marks
• Chips
• Delamination

A small crack can quickly become a complete failure during the next landing.

If you are unsure whether carbon fiber has been damaged, replacing it is usually the safer choice.

Do Not Forget the Mounting Plate

Many landing gear failures actually begin inside the airplane.

The landing gear mounting plate absorbs tremendous loads every time the wheels touch the ground.

Inspect for:

• Loose mounting bolts
• Cracked plywood
• Broken glue joints
• Soft wood
• Elongated bolt holes

Remove the wing occasionally so you can inspect the mounting area thoroughly.

Catching a loose gear block early is much easier than rebuilding the bottom of the fuselage later.

Check the Firewall Too

On many tricycle-gear airplanes, the nose gear is attached directly to the firewall.

A hard landing can loosen both the nose gear and the motor mount.

Inspect for:

• Cracked firewall glue joints
• Loose blind nuts
• Loose nose gear steering arms
• Bent nose gear wire
• Worn steering collars

A loose firewall affects much more than just the landing gear. It can also change the motor’s thrust angle and lead to additional structural damage if left unrepaired.

Steering Components

Nose-wheel steering often develops slop over time.

Inspect:

• Steering arms
• Pushrods
• Wheel collars
• Set screws
• Servo arms
• Linkages

The nose wheel should center smoothly without excessive play.

Loose steering can make takeoffs surprisingly difficult and may even contribute to ground loops on taildragger aircraft.

Tighten Hardware Regularly

Landing gear hardware experiences constant vibration.

Wheel collars, mounting bolts, axle nuts, and steering hardware should all be checked periodically.

Metal-to-metal fasteners may require a small amount of removable thread-locking compound.

Never use thread locker on screws going into plastic unless recommended by the manufacturer.

A few seconds with a hex wrench before flying can prevent a much longer repair session later.

Repair Before Flying Again

It can be tempting to straighten bent landing gear and continue flying.

Sometimes that is perfectly acceptable.

Sometimes it is not.

If you are unsure whether the gear has been weakened, replace it.

Landing gear is inexpensive compared with repairing a damaged fuselage, wing, propeller, or motor after a collapse during landing.

Grass Fields Need Special Attention

Our club’s grass runway is maintained beautifully, but grass fields naturally place more stress on landing gear than smooth pavement.

Small holes, uneven ground, soft spots, and thicker grass all increase the loads placed on the gear during takeoff and landing.

After flying from grass:

• Remove grass wrapped around the axles.
• Check wheel collars.
• Inspect wheel pants for cracks.
• Verify the gear has not shifted.
• Look for loosened mounting bolts.
• Clean away dirt that may hold moisture against metal parts.

A quick inspection takes only a minute and may prevent problems on your next flight.

After Every Hard Landing

Any landing that makes you say, “That wasn’t my best,” deserves a careful inspection.

Take a few moments to examine:

• Landing gear alignment
• Wheel movement
• Mounting bolts
• Gear blocks
• Firewall
• Nose gear steering
• Propeller
• Spinner

Many landing gear problems are discovered before the next flight simply because the pilot took a few extra minutes to look things over.

Prevention Is Always Easier

Landing gear repairs are usually straightforward when caught early.

Replacing a bent axle or tightening loose hardware is much easier than rebuilding a torn-out landing gear mount.

Develop the habit of checking your landing gear before every flying session and after every rough landing.

Those few extra minutes can save hours of repair work, protect your investment, and keep you flying instead of repairing.

Keep It Ground-Ready

Every successful flight begins and ends on the ground.

Strong, properly maintained landing gear helps protect your airplane during every takeoff and landing while giving you the confidence to focus on flying instead of worrying about what might happen when it is time to touch down.

Treat your landing gear as an important part of your airplane—not just something that holds it off the ground.

Your next landing may thank you for it.

Have you ever repaired or upgraded landing gear after a rough landing? Share your experience in the comments. Your tip might help another pilot avoid the same repair!

Happy Flying!
York Area Radio Control Club