RC HELICOPTER MATERIAL HAS TO TAKE A LOT OF STRESS.
Choosing the correct RC Helicopter Material shouldn't cause you stress too. Let's look at the common ones and figure out what is best for you.
A RC helicopter has to endure all kinds of stresses such as high and low frequency vibrations, heat, G-forces, centrifugal forces, hard landings... OK you get the picture.
So you want your RC Helicopter Material to be strong enough to with stand all that and be light enough so your helicopter can actually fly.
First off, when I am talking about RC helicopter material, I am referring to the material that the main frame and tail boom sections are made from, not the body. Body materials are discussed in the
Scale and Pod-and-Boom
The main frame is what holds and houses all the mechanical components of the helicopter such as the engine, clutch, gear systems, rotor shaft, control mechanism and perhaps the servos, gyro, and fuel tank or batteries. You know the “guts”.
The tail boom is the long section that attaches to the main mechanical section that of course has a tail rotor at the other end.
Not long ago, the only RC helicopter material to use was aluminum. Aluminum is strong and light, dissipates heat well, and is inexpensive. It is still the most common material in use for both the main frame structures and tail boom sections of most nitro, gas, and turbine RC helicopters and some larger electric ones. However, it tends to be too heavy for small and micro electric models.
Other than being too heavy for micro helis, aluminum has two other minor disadvantages. Over time it can develop stress cracks. This is more common with nitro engine helicopters because of the very high frequency vibrations associated with engines running at 15 to 18 thousand RPM. These cracks will usually occur where the engine is mounted to the side frames or at the starter shaft bearing block (if your heli uses this starting method).
This stress cracking could also be a problem with
turbine rc helicopters
as well, although I have never heard of it happening yet.
The other problem that I have seen with aluminum is during a hard landing or crash; the frame structure can bend and go unnoticed. This would cause alignment issues, that if not discovered right away will lead to stress, wear, or catastrophic failures of moving parts or the entire helicopter.
Plastic solves both these problems because it absorbs vibration much better, and instead of bending and staying bent, it will return to its original shape (unless it is bent past the point of no return and breaks).
Plastic is very inexpensive and relatively light for the amount of strength it provides. It doesn’t take heat well, but on an electric model that is not an issue. Most nitro engine set ups with plastic frames use an aluminum portion where the engine mounts. This assembly is then mounted to the plastic side frames.
Plastic is not as strong as aluminum and is generally used on small and lower priced nitro models or electric helis. To the best of my knowledge, plastic has never been used on a gas or turbine model. It is simply not strong enough and flexes too much. Plastic is never used on tail booms for the same reasons. Tail booms are always made of aluminum or carbon fiber.
Fiber Glass, also called glass fiber(GF), is becoming more and more common on mid to high end machines while saving some coin. It offers many of the good characteristics that Carbon Fiber does. GF absorbs high/low frequency vibrations, is fuel and heat resistant, and most people like the look of it.
Fiber Glass frames are not as ridged as carbon fiber and weigh more, but for the average flier, they work very well and cost a good deal less than carbon fiber frames. You can find fiber glass being used right from small birds up to huge turbine powered machines and it works work well with all fuel types and electric power options.
If you are looking for a solid frame structure but need to save a little money, a Fiber Glass frame is certainly a good compromise between price, strength, weight, and even looks...
Where would the world be with out Carbon Fiber? Yes, almost everything from fishing poles to jet aircraft have benefited from it, and the world of RC helicopters is no exception.
Carbon fiber seems to have been tailor made for our hobby. It is stronger and lighter than plastic, aluminum, & fiber glass; absorbs vibration better than aluminum, and handles heat and cold. It can be molded to be super stiff in one direction and flex in another direction.
Unfortunately, most of us don't have a money tree growing in our back yard. Even though carbon fiber has come down in price over the years it remains expensive, but not out of reach.
For your first helicopter, it is probably not the best choice. Even though it is stronger than aluminum and fiber glass, it will still break in a bad crash and cost quite a bit more to replace. A general rule of thumb is two to three times more expensive than aluminum of fiber glass pieces. One thing you might want to look into when choosing your helicopter is if you can up-grade to a carbon fiber frame set and tail boom for your particular model later on. This is a great way to go, you learn on plastic or aluminum or fiber glass and then once you are a proficient flyer – purchase a carbon fiber frame set and boom.
As the price of carbon fiber keeps coming down, it will become the main material in RC helicopter construction – it is just so good for so many reasons.
Even more confused now on what RC helicopter material you Should Consider?
Here are my recommendations for the beginner:Plastic: Micro to small electrics(100-400 series).Aluminum: Larger electrics (500-700 series), all nitro, gas, or turbine. Fiber Glass: Good for mid to large sized electrics, nitros, gassers, and even turbines. Not as ridged, strong, or light as carbon fiber, but for most types of flying is more than adequate at a good price. Carbon Fiber: Perfect for everything but expensive. Learn on plastic, aluminum, or fiber glass unless you have deep pockets and then upgrade to carbon fiber. It will soon become your material of choice.
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