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Why did I upgrade my Wltoys A979b?
After the initial run of my TRC truck, I found that it spinned a lot. Whenever I gave it full throttle, it would spin.
Also, this truck uses a plastic steering system, and its wheels can move without moving the servo arm. Thus, the truck cannot run straight. Thus, I can never run this truck at its full potential – 70 km/h. For these reasons, it is a good idea to use aluminum parts to overcome these problems. With aluminum parts, you can make a lot more adjustments on my RC truck, not to mention that the truck can become more durable.
Here are the things I noticed while upgrading my a979b to full metal
The upper desk for a979 is different from the one for a979. The one for a979b has enough space for the big reduction gear.
Enlarging the Battery Holder
This RC truck comes with a small LIPO (1500 MAH), so the running time is only about 10 minutes. At the same time, I have 3 LIPOs with 4200 MAH each sitting idle, thus, I have tried the way to use all these LIPOs without investing any more money on buying any new LIPO. Later, I found out that after you replaced your plastic upper desk to a metal one, instead of placing the ESC next to the LIPO, you can put a LIPO on the top of your upper deck. By doing so, you can increase the size of the battery holder by 30%. It is enough for holding each of my old LIPOs.
Do not expect that aluminum parts are perfect. While you do not get stripped screw too often if you use aluminum parts, some aluminum parts might not have a perfect fit while you install it. To fix this, you can go to a hardware store and buy some aluminum oxide abrasive papers. You can use them to sand away the extra layer of your parts.
When you buy the optional part for the a979b or any other Wltoys RC car, the seller does not usually provide an instruction. The sellers said it is not easy for them to produce the instruction that is clear enough for the hobbyists to use. You might think that no instruction is needed as you can always go back reading the manual included in the package, but it is not feasible as the manual is too focusing. You can download the A979 manual here. Here is a copy of the manual you can take a look. Without the proper instruction, if you are as careless as I am, you might find yourself in installing your optional parts in the wrong direction. To solve the problem, I find the instructions published by some hobbyists on YouTube. You can find one of these on the top of this post.
Screws and Glue
I found that building this car requires you to have some extra m2, m2.5, and m3 screws as some sellers might forget to give you enough. You should check if you can find those screws on eBay before you start your project. Besides, you will need some screw glue as you will need to tighten the screws once you make sure that you have installed all the optional in the correct positions/directions. The glue is essential! However, if you use too much glue on your parts, you might need to use an air blower to soften the glue, in order to get the screws out when it is necessary.
Body Posts and Shock Stands
While you are using aluminum posts and shock stands, you might find that you need to re-drill the body as the position of the posts might change. In my case, I need to make the hole a little bigger.
The Electronic System
The original servo has five wires and with plastic gears. It is not a standard size servo. If you plan to replace it with one 3 wires and metal gears, you have to make sure if you get the right size of it. Never buy a servo that is too small. Otherwise, you cannot use a servo saver. As the ESC and the receiver are in one unit, it is a good idea to replace the whole electronic system if you want a stable system.
Check out one of the servos that fit the 1/18 Wltoys RC car. The size of the original servo is 28mmX13X27mm. You need to look for a servo about the same size. Otherwise, your car will have a hard time to run straight.
I also use an aluminum servo stabilizer as I can secure the servo much easily.
The above image shows the shocks you should get if you want to replace the original plastic shocks. These shocks has enough power to suppor the chassis and can be adjusted. Overall, its quality is acceptable.
The image above shows the shocks that you should not get. I wasted some money invested on those useless shocks. They are too solf so they cannot support the chassis very well. Also you can not make any adjustment on them. Overall, they are useless.
As I tried to upgrade to metal gears, I found out that I have just wasted my money as a979b has included a full set of metal gears for the cars. I am too careless. One of the sellers on Taoboa.com confirmed that the release of a979b has included a full set of metal gears and the central shaft. There are still some old versions of a979b in the market so when you buy one now, you might get the one with plastic gears. Thus, if you have an a979b, and you want to upgrade to full metal gears, you need to open the gearbox first before you place an order.
While upgrading my a979b, I found that I need to decide whether I should replace a small part for the truck. Look at the image below. The part number is A979-03. Later, I found out that it fits the front and rear end of the truck. While this part is made of plastic, it is an important component holding the a-arms. There is an aluminum alternative in the market, but it is relatively expensive. ($4.99 vs $12.90 online). As I am using metal bumpers, I think using these plastic arm holders should be enough.
As my skill level grows up, I might get a brushless system. Anyway, it really depends on where I run my truck. If I mainly do bashing, the brush-less system should bring up the excitement. On the other hand, if I run it on a small track, I will stay with the brushed system as running on a track does not require high speed but accurate handling. In fact, this RC truck is overpowered already with its original brushed motor.
If you are an absolute beginner and hate running car that cannot run straight, do not buy this little truck. With plastic or aluminum parts, it still has much slack. It really takes a professional / or semi-professional to have this little truck set up right so that it can run straight and be competitive on a track.
A979b is a great little RC truck at a cheap price. For such a small size, it is equipped with a 540 brushed motor. While it has a lot of weaknesses, its potential for upgrading is wonderful. I have seen a lot of people run these Wltoys RC cars on the track such as the YMT in Hong Kong. It is so competitive in the track. In fact, it is the main reason why I get this RC truck. It is a challenge to set up this truck right.
Unknown Hong Kong track
Will you buy this RC truck? If you have this RC truck already, will you, just like me, upgrade it to full metal? Just leave any idea you have about this truck and its upgradability.
Thanks for reading this post.
Written and Edited by Carlos Santos, your webmaster.
This post has already been read 102 times!