RC Cars: What You Need To Know Before You Buy One

RC or radio controlled cars can range in price from less than fifty dollars to thousands of dollars. If you are planning to buy your first RC car, you may be scared by the difference in price of RC cars, not to mention the huge variety of models that are available. If you are planning to buy your first RC car, then getting to know some of the basics that determine the price and performance of remote controlled cars will help in making your decision easier.

Some of the main things that you need to know about radio controlled cars before you select and buy one are:
1. The Grade: The price of the same model of a radiocontrolled car can greatly vary based upon whether it falls into the toy or the hobby grade. The hobby grade of cars includes radio controlled machines that are built for the RC enthusiast, and thus come with the best features, functions, durability, speed and scaling. On the other hand, toy grade machines are just that—toys that are built for kids, but even these might offer quality and a host of features based on their price. If you are an adult venturing into radio controlled racing, then you might want to invest in a hobby grade car or a high end toy grade car to get started and in order to perfect your driving skills.
2. The Fuel: Radio controlled cars today can run on different energy sources, ranging from batteries to petroleum. The latest of these are the gas powered cars. These cars are generally built to a larger scale than other types of radio controlled cars and run just like normal automobiles, producing fumes and noise in the bargain. Their engines are petrol driven and while their tanks can carry fuels for long distances, they are slower to accelerate than RC cars that run on other fuel sources.
The oldest type of RC cars is the one that runs on batteries. These RC automobiles rely on rechargeable batteries for power. Most racing enthusiasts keep spare batteries for races so that they can replace a car’s exhausted batteries mid race. The advantage of battery run radio controlled cars is that they are the cleanest and the easiest to control. Being light weight, they accelerate quickly without producing noxious fumes.
In between these two kinds lies the racing enthusiast’s favorite—the nitro car. Running on a combination of nitro-methane and lubricating oil, these cars can accelerate fast and achieve higher speeds than both gas and battery powered cars. However, because of the fuel used, they tend to produce both noise and exhaust, which is great if you are racing outdoors, but may prove painful if you are running your car in the drawing room even for a small period of time.
3. The Terrain: Radio controlled cars can be either off road or on road. On road models have racing tires and are built for high speeds for on road racing. On the other hand, off road RC cars generally come in the form of SUVs, trucks or truggies and have broader tires that provide a good grip over rough terrain. These are always slower and more rugged than on road RC car models. Both types come with all three energy options.

Replacing Main Rotor Blades of RC Helicopter

The main rotor blades can become cracked in a severe crash and pieces can break off. While it’s completely possible to fix small cracks and dings with some medium CA glue and accelerator, this can negatively affect blade balance and make the helicopter vibrate. It’s easier and faster to replace the old blade so here’s how to do it:

Get a small Phillips head screwdriver and unscrew the single aluminum screw at the root of the damaged blade. The blade will now be free, and you can remove and dispose of it. Damaged blades can be sharp, so be careful not to cut yourself.

All the top rotor blades come with a white warning label on their upper surface. Choose from the upper and lower rotor blades as needed so that the rotors look like this when viewed from the front. As viewed from the front, the right top rotor blade should curve upwards and the bottom right rotor blade should curve downwards. This picture shows the correct blade orientation. 

Install the replacement blade and tighten the screw just enough so that the blade swings freely when you tilt the helicopter, but is secure enough that it won’t fly off. This has to be done by feel – it’s not critical that the screw is perfectly adjusted, but the blade should feel secure and move freely.

Replacing the Blade Grips

The blade grips / holders are black clevis like objects which clamp down on the root of each blade and hold it to the main shaft. If one of these becomes damaged, use this procedure to replace it:

Remove the both of the rotor blades that the blade grips are holding by following the instructions above.

Lay the helicopter on its side and observe the two screws that hold the blade grips together and on the main shaft. This picture shows one screw removed, viewed from the bottom of the helicopter. 

Unscrew the blade grips and keep the screws in a safe place where they can’t roll away.

Replace the broken blade grip and install the screws.

Replacing Ball Linkages:

Ball linkages connect the RC helicopter’s servos to the swash plate and fly bar. It’s fairly unlikely that these will get broken in a crash, but if they do, here’s how to replace them:

Snap off the damaged ball link using your fingers or a screwdriver.

Find the replacement link that matches the one you took off and press it on to the spherical plastic nubs where the broken link connected.

Remote Control Helicopter Maintenance Tools

Remote control helicopters require constant maintenance. Investing in the right tools right from the get go will save you a lot of time and money. Trying to construct your own helicopter without the proper tools will most likely lead to a crashed aircraft and even if you purchase a ready to fly remote controlled helicopter, you will still need the proper tools for its maintenance. Don't waste your money buying every available helicopter tool, start with the bare essentials and over time, you will know exactly what tools you need for each job.

The simple helicopter pitch gauge is utilized to align the pitch angle and the type of range of pitch that your main rotor blades will have. This is one of the most important tools and is used even for ready to fly models as you need to confirm whether the pitch angle and pitch range are correct.

Do not rely on the cheap, poor quality tools that come with most remote control helicopters. It is better to invest in your own assortment of metric Allen Drivers. The best way to do this is to start with a nice basic set then buy hex and nut drivers individually.

To prevent damage due to vibrations, get a Dubro Balancer which can be used for engine cooling fan balancing and airplane propeller balancing. Make sure you also buy a good soldering iron and station with adjustable heat settings, replaceable tips, cleaning pad and holder.

For the electric powered remote controlhelicopters, make sure you buy a good quality computerized battery charger. This can also be used to power the on-board electrics on your fuel powered models.

Lastly, be sure to purchase different types of bearing greases and the general lubricating oils, epoxy glue, instant CA glue, blue medium strength loctite, a good quality metric ruler, an electric drill and drill bits, heat shrinking tubing and nylon tie straps.

Remote control helicopters are the most rewarding of all RC hobbies and part of the fun is all the work that goes into it. Without the right tools, it will be impossible to finish a project and lots of first time buyers end up abandoning the project altogether after getting frustrated at the length of time it takes. Make sure you research on remote control helicopter repair tips before attempting any work yourself.

Remember to keep your most essential tools in one tool kit and carry them wherever you go because all remote control flyers have experienced crashes or damages no matter how skilled they are. So invest the time and resources in building yourself a nice and properly equipped work station, get flying and experience the joy you can experience from remote

Hydro System Tips for RC Boats

I will explain the most important setup aspects for sport hydro RC boats. The points covered can also be applied to some outrigger hydros. I will not cover things like center of gravity and engine placement as these should be supplied by the boat manufacturer. In most hydro’s the engine will end up being considerably forward of the leading edge of the turn fin. The CG will end up closer to the leading edge of the turn fin. This is generalizing and varies from one boat to another. The turn fin is what the boat "pivots" on when the rudder is turned. Moving the CG away from the point of pivot changes the turning characteristics of a hydro considerably.

There are three (3) pieces of hardware to adjust and fine tune on most hydro’s. These are:

The strut

The rudder

The turn fin

Adjusting the Strut: 
To do this, it's usually easier to remove the rudder blade. If the rudder extends past the back of the strut you can leave it on, otherwise remove it so you can move the boat forward on the table and have the entire strut bottom over the table surface. This is important when adjusting the strut angle.

In most cases the manufacturer will recommend 0 angles on the strut. They should also recommend a starting depth for the strut, usually measured from the bottom from the boat at the transom to the center or bottom of the strut. Lightly tighten the adjustment bolt(s) and double check your height. Make sure the strut is still flat on the table. This is checked by ensuring you do not see light under the strut when looking at it from the side, parallel to the table. Fasten the adjustment bolts and triple check the strut.

Setting the rudder: 
Setting the rudder is pretty straight forward. Unless the manufacturer specifies otherwise, you will usually want the rudder perpendicular with the riding surface of the boat. In this case, this means perpendicular to the table surface you just used to set the strut. For this reason it is VERY IMPORTANT to set the strut first!
With the strut adjusted, install the rudder blade and check that it is 90degrees with the surface of the table. The boat must be sitting flat with the strut and both sponsors on the table. If the manufacturer recommends some inner or outer tilt, you can check and adjust with a protractor again using the table as reference.
Setting the turn fin: 
There are two different types of turn fins more commonly seen on hydros. One has a straight bend and the other is a curved type. In most cases the manufacturer will specify where to mount the turn fin and how to adjust it. Again this varies from boat to boat.
Tilting the fin forward will have a tendency to make the boat track to the left and exert some lifting force on the right (starboard) sponson.
Tilting the fin back will have a tendency to make the boat track to the right and pull down on the right (starboard) sponson.

I hope this will help some of you fine tune and get the best possible performance out of your hydros!

How to correct the scheme of the boat

Center of  Gravity: The chapter How to Assemble R/C Boat, in the Technical session, shows how to calculate and adjust the CG. It's easy to understand that a CG towards the front tends to maintain the bow down into water, increasing the wet area and hampering the planning of the boat when at speed. On the other side, a CG too close to the transom tends to raise the bow too much, making the boat unstable at speed. As a rule of thumb, CG must be between 27% and 30% of the total length of the boat, measured from transom, for a completely assembled boat - ready to run except for the fuel. As very powerful engines tend to raise the boat's bow, under those circumstances a CG over the upper limit (30%) may be advisable. On the other hand, mild engines will be happy with the 27% rule.

Strut Angel: A strut has a positive angle when the prop shaft points upwards, far from the water surface. In this situation, the transom is pressed down. A negative angle occurs when the prop shaft points down, towards the water surface, raising the transom. If you imagine the boat supported on a transverse shaft that goes exactly through the CG, it's easy to understand that, when the transom is lowered the bow goes up, reducing the wet area. The contrary occurs with a negative angle for the strut. Although apparently we could use the strut angle to correct any incorrect attitude, the truth is that the neutral angle is the ideal, just a few degrees off are allowed to adjust the wet area. If more than 2 degrees are necessary, something else should be wrong.

Trims Tabs: Normally 2 are used on each side of the boat. The outer ones take care of the behavior of the boat on turns, the inner ones of the attitude when traveling in a straight line. We will take care of those from now. Increasing the trim tabs angles - orienting down the adjustable portion - raises the transom, dropping the bow - the boat increases the wet area. Inversely, reducing the trim tabs angle - directing up the adjustable component - lowers the transom and raises the bow, reducing the wet area.
Outer trim tabs act on turns. Remember, adjusting them to raise the transom makes the nose dig on turns, making the turns eventually sharper than desired.
Once again, the degree of possible actuation is limited - if correcting the attitude demands more than few degrees of actuation, we must look in another place the solution of the problem. 

Hooks and Rockers: Hook is a concave surface on the bottom of the hull, near the stern, that acts like a big trim tab and raises the transom - lowering the bow and increasing the wet area. Rocker is exactly the opposite - a convex area near the stern that lowers the transom and raises the bow.

Some manufactures claim that those surfaces are made on purpose on their hulls, to determinate the attitude of the boat on water. I don't like the solution; I prefer to believe that both are defects that must be corrected. The scheme of the boat must be determined by devices that allow adjustments and not by this way.
The correction is very complicate. The rocker must sanded until be level with the bottom of the hull, the hook must be filled with and sanded.
Both corrections are complex and time consuming, reason why I suggest you to avoid a hull with any of those characteristics. 

These are some tips to adjust the scheme of the boat for those who want to build RC boats on their own.