When looking for your
best RC helicopter
, you may notice Bearing Count listed under the helis' features.
What does it mean and why is this important you ask?
This number simply refers to the quantity of ball bearings the RC helicopter uses. An important item because all hobby grade helicopters require a minimum number of ball bearings and manufactures will want to include this information as it adds value to the RC helicopter kit. Generally the higher the bearing count, the better quality helicopter you are getting.
Why are bearings important?
There are many items on your helicopter that rotate and pivot. For a shaft to pivot or rotate, it must turn inside a bushing or ball bearing. Bushings offer weight savings and are inexpensive, but they wear out much faster than ball bearings. Once worn out, the fit is sloppy and results in unwanted movement, play, or vibration in the component - the helicopters worst enemies.
Bushings therefore have to fit tight around the shaft that is rotating inside them to eliminate excessive amounts of play. This “tight fit” leads to the other problem with bushings, they have substantial amounts of drag so more power is lost due to friction.
Here is a pretty good video I found illustrating just how much better bearings are at reducing drag. It is on a
toy RC helicopter
, but the benefits of bearings over bushings are apparent in any aspect of rotating mechanical components.
When you are starting out, you certainly don’t have to get a RC helicopter kit with a huge number of ball bearings, but you should know the areas of the helicopter that really should or must use ball bearings. What is a huge number? Top of the line RC helicopters can have bearing counts of 60 or more bearings.
A decent quality RC helicopter should have a bearing count of a around 20-30 ball bearings. This number really depends on the type of kit you are getting, but it is a good starting point. Electric helis will generally have a lower bearing count than fuel powered helicopters since they don't require clutches and starting shaft systems.
It is actually pretty simple to figure out what components on a RC helicopter should have ball bearings. Just ask yourself this question:
“What parts of my helicopter rotate and pivot many times during a flight”?
gear box or tail drive belt shaft and belt tensioner
Tail rotor blade holders
Tail rotor pitch sleeve
The above list of components spin or pivot hundreds or thousands of times per flight and/or have heavy rotational loads; that is why it is so important to ensure these components use ball bearings over bushings. I strongly recommend you use this list as a minimum guideline for what components on any hobby grade RC helicopter have ball bearings.
Remember me saying on the home page that the quality of RC helicopters keeps getting better and the costs keep going down. Here is a prime example of that. Most average kits today now come with higher bearing counts than they did a few years ago at the same or less cost.
There are many other components on your helicopter that pivot, mostly the control linkages. This is where the higher end RC helicopter kits will also use ball bearings. It is not critical when you are learning to have bearings on these components because they don’t move as many times and will take longer to wear out. You generally don’t need the fast precise control that a more advanced heli pilot is looking for – another reason control pivot points will work fine with bushings when you are starting out.
Over time as the bushings wear, you might want to replace them with ball bearings. Most quality manufactures will offer bearing upgrade kits to replace the plastic bushings with high quality bearings down the road. This will allow you to save a few bucks up front when you purchase your RC heli kit. By the time some of the bushings wear out, you will be a proficient flier. You will now notice and appreciate the quick and precise control that the ball bearings offer – a perfect solution.
If you already are a good RC heli pilot and you are looking for a more advanced heli - get one with as many bearings as possible. While bearing upgrade kits are available, they will tend to cost more in the long run than if you were to get a top end RC helicopter kit right off the bat.
Ball Bearing Tips
No matter what your bearing count, ball bearings will wear out over time, just not nearly as quickly as bushings. Dirt and moisture are the main culprits of premature bearing failure – rough rotation, binding, and corrosion are the results.
At least once a month, you should go over your helicopter - pivot and spin all the components by hand to feel for any roughness, binding or slop in any of the bearings. Have a look at the bearings for any signs of rust or corrosion.
If you find a bearing that is suspect, remove it, clean it, and re-oil/grease it. I find 75% of the time; this is all that is required to get a bearing running like new again.
If you do have to replace a bearing or two, I have found that good quality commercial or wholesale bearing shops will often sell ball bearings at much better prices than the hobby shops can – often the quality is better too.
Just take your old bearing/s in so they can measure it/them to see if they have any in stock. You could also e-mail, fax or call them with the exact dimensions of the bearing if you are proficient at using a micrometer or caliper.
Most bearing shops will have or can order in the bearings you need - remember, RC heli manufactures don’t custom design ball bearings to fit their kits – they engineer their kits to use ball bearings that are already on the market.
For any of you RC car people out there – these bearing tips will help you out as well. I know my RC ground vehicles go through bearings much faster than any of my helis do. These tips have saved me a lot of time and money in both hobbies.
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