RC Part 18: arrma limitless 1 / 7 RC remote control vehicle - breaking the limit speed (the fastest 243km / h at present)
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When it comes to arrma, a remote control car brand, it translates to Amar (link). The author understands that he is not very early. From several chats, many model friends have his car with good quality, durable and easy to play RC. Everyone must like it. Later, I found this promotional film of arrma limitless on the Internet. I feel that first, it is handsome in appearance and F1 in shape, so we all use F1 to replace arrma limitless for domestic model friends; The second is the characteristic of this car, which is born for the limit. It translates to unlimited meaning. The official claims that it can run to 100mph, that is, 160km / h. This speed is very fast, pointing directly at the xo-1 of traxxas.
It's been a long time since I started booking and got it. The time of October 21 finally arrived. During this period, I just caught up with the activity of Taobao 9.9. Coupled with the gold coin, I got it at 2538. It's a relatively good price.
It's a very large box. There are some instructions for the general agent in the lower right corner, including warranty and so on.
The side introduced some features of the car, such as quick disassembly of the motor.
The other side, printed on the side of the car. The boxes are broken. The express is too violent.
On the side of the short side, it is told that the front and rear spoilers can be cut off with scissors to find their own suitable downward pressure.
The attached car shell column, wrench and motor teeth of 27t 5mm hole 1 die for other car shell refitting. In addition, the author bought 34T motor teeth of xo-1 for refitting later.
Stickers and an information card have a gear ratio range. The minimum gear ratio can be set to 2.13, which is very terrible. The maximum gear ratio is 5.86.
Let's start with the handsome front view. The F1 shape and the two large spoilers in front are too high. In this way, although the downward pressure is enough to make the car stick tightly to the ground, the resistance is also large, which is not suitable for extreme speed. I think many foreigners have removed it, but one risk of removal is that at 170km / h, many people's cars turn upside down after taking off... So we should adjust the shock absorber to make the rear shock absorber very hard.
In the side view, you can see that the slender body, 406mm wheelbase and the third-party adapted traxxas xo-1 shell can be used in general. It seems that someone has tried it abroad. The tires are also very handsome, and there is a wide rear spoiler at the back.
In the top view, at first glance, you may see that the rear wheel feels a little inside eight because of the wide-angle distortion effect, but in practice, the rear wheel does feel a little inside eight. I like the overall blue body very much. The front and rear are fixed by r-clips, and the r-clips are also connected and fixed on the car shell, so I don't have to worry about losing them.
The diffuser at the rear is very similar to the real car, and there are brake lights. Unfortunately, it's just decoration. In the later stage, it can be changed into linkage lights.
In the middle of the bottom plate is a whole aluminum alloy plate, which is not flat. It has aerodynamic design and cooperates with the final diffuser. After careful observation, we can find that there are screw holes around the diffuser, which are reserved by the government. You can screw in titanium alloy screws to soften the shock absorber. When starting, the screws can rub the ground and make sparks. It's very fun.
Take away the car shell and you can see the layout inside. An aluminum alloy column in the middle runs through the front and rear, which can enhance the stability of the vehicle. The rear two battery compartments with adjustable length. By default, the motor is in the red aluminum alloy motor base. The motor is on the side facing the front of the vehicle, but it is impossible to put too long motor. The maximum motor is TP 4050, which is 82mm long and 90mm long. But at this time, you must think that such a large space can only accommodate a small motor, which is too wasteful. The official also thought that the long motor can be placed on the whole right side by removing the motor base and rotating it 180 °. For example, the TP 4070 series commonly used in extreme speed at home and abroad can be put down, and there are still many spaces left. At this time, the battery can only be stacked on the left side or placed in front and back, To realize series or parallel connection.
The front of the right side is the position of the small electric regulator. In front is the waterproof box of the receiver. Near the middle is the fixed position of the steering gear. The front part is quite compact. It comes with a metal steering arm.
The motor base made of aluminum alloy has two special m4x14 screws on the top. The original factory says 12.9, but when I screw it down and then screw it up, one of them is a little enlarged. Fortunately, I can screw it out by pressing it hard. I'm ready to replace the Fangsheng 12.9 screw.
One big difference between the original 34T middle gear and the pickup version is that the pickup has a middle differential, while F1 does not. The author also bought the official 29t middle teeth to reduce the tooth ratio. As a result, there were agents in China just after the overseas Amoy. The price was cheaper and it was a hole. The empty position of the middle and rear transmission shaft is very large. When idling, you can see the shaft shaking back and forth like a rubber band, and the official doesn't care. However, the domestic general representative thinks it's a problem. He pays for a better root, and the test effect is much better than that of the original factory. He sends it to the users who buy it through the domestic agent free of charge, and only needs to pay the freight.
The shock absorber, the spring soft and hard adjustable range is quite large, the author adjusted the rear to the hardest state according to the fastest record configuration, so that the height of the rear chassis is greater than or equal to the height of the front chassis as much as possible to reduce the take-off. possibility.
Steering section, and anti-roll bars, but the void is too large, larger than any climbing bike I have played, mainly the void of the ball head.
The front spoiler can be removed with these two fixing screws, and the instruction sticker is very interesting.
The ARRMA LOGO on the side of the front shovel, and the front shovel and rear rear wing are all plastic, with average rigidity. I bought a carbon fiber panel customized by domestic people, and it can be lighter and stronger when I replace it.
I think the front and rear support rods are sold by CNC, but the author shook it hard with my hand, and I felt that there was no empty space, and I felt that there was no need to replace it, and the price was not cheap.
The original rear shock absorber also has an anti-roll bar. Below the middle of the picture is the fixed position of the rear case. In addition, the virtual position of the rear wheel is also very large, and the hand can make the tire sway left and right.
The large spoiler at the top is also very high and steep, like a wall, so the resistance is also large. The official manual is for everyone to use scissors to shorten the front and rear spoilers according to their needs, so the playability is indeed higher, but it is very troublesome to cut, because the plastic is a bit thick, the author based on the current fastest record of this model. Configuration, basically cut off the rear spoiler, leaving only a little on both sides.
The vertical panel of the tail is also made of plastic, and its rigidity is very poor. It can be deformed with a little effort of the hand. The last time I saw a foreigner take off, this one was directly smashed. It is printed with the LOGO of Horizon. After the carbon fiber panel is replaced, the LOGO of the equipment I use will be pasted.
The quality control is still very poor, the vertical version of the rear wing on the right side is not polished, and the left side is fine.
The tires are full of details, and they are really beautiful, but the quality is also very poor. Many foreigners who have punctured tires have replaced them with grp tires or even better bsr sponge tires.
The author accidentally unloaded the floor oil, threw the pie, and then hit the front shovel. The official design is too close to the tire. Then the tire fell off. It can be seen that the plastic wheel has only a little bit of glue on both sides to fix the tire, and the original wheel is not rigid, and it can be deformed by hand, which is not as strong as the bsr wheel.
The tire was scratched by the front shovel, and the fiber cloth on the inside of the tire to prevent it from blowing was also broken.
Group English is also printed on the inside of the car shell, don't just rush.
Electrics and Retrofits
A good saddle and a good horse, the most important thing in the car is the motor. The author chose a TP 4070cm 2200Kv motor, which supports up to 8S battery and a maximum power of 90000W (only lasts for 10s). A price of 1500 yuan can be said to be the most expensive in China. The motor is gone, TP has a better reputation abroad, and many marine competitions use TP motors.
Compared with Surpass4092, it is just a little longer, 107mm in length.
The weight is very sufficient, the official standard weight is 640g, and there are 4 magnetic poles.
The bullet head of the motor has to buy 6.5m by itself
m welding. TP's LOGO and website are printed on the side, as well as Kv display.
There is also a traxxas big X ESC from Salted Fish for 100 yuan. It has no fan and has a maximum continuous current of 160A, which is the benchmark for Hobbywing max6.
Capacitor supplements need to be welded in parallel by themselves. Does the capacitor have any effect and what is the effect? The author will explain some problems through comparative tests in the later measured posts. The current conclusion is that the capacitor is mainly used for voltage stabilization. Under such a large current discharge, the voltage of the battery will drop rapidly, and the capacitor can play a role in voltage stabilization. To prevent the voltage from dropping too low, this can also protect the battery from instantaneous over-discharge, and can also reduce the pressure of the ESC. The general installation is to weld in parallel with the power line of the ESC.
In the first stage of the power set, there is also a large receiver of Fuss NB4. It is said that the distance of 500m is suitable for running at extreme speed. Many other people use the range extender, which can make the remote control distance farther, more stable and not out of control. .
Because the position of the battery compartment on the right side of the author is reserved for the motor, the battery can only be stacked on the left side or in the front and rear, because the author chose the Grignard 4S RS series 6750mah 100C battery, which is very high, nearly 5cm, so I can only choose the front and rear. It is placed, and foreigners also place it in this way. I just bought a carbon fiber battery board for climbing, which is the most cost-effective, and the aluminum alloy baffle perfectly matches the width of the battery. I shorten the length of the battery board so that the battery will not shake back and forth. This is the length comparison before and after Zhang's transformation.
Perfectly stuck the battery.
On the back, I used the drill bit I bought with the electric batch to drill the holes, and drilled 3 holes for each battery plate. Because there is one that is right on the curved surface of the aluminum alloy bottom plate, it is not easy to fix it.
The baffle in front of the small ESC is very obstructive, which is not conducive to the enlarged ESC, and there is not much space behind the motor. The ESC can only be placed here first, and the baffle is cut off. Because the steering gear of the speed car does not require high torque for climbing, I chose a good steering gear from VGOOD, which has a very fast response speed.
In the second phase of electrical equipment renovation, the ESC was replaced by the strongest domestic Hobbywing 200A ESC. The instantaneous current is more than 1,000 A, which is a bit larger. Although it does not have the detailed data recording function of XLX, it is equipped with the built-in WiFi extender. , you can also see the motor speed, voltage and temperature data. The battery is not going to use the cheap TCB 4S 5200mah 45C battery that I bought before. The discharge capacity is poor, so I chose the Grignard battery, and one can buy more than 4 TCBs. If there is a chance in the future, MGM ESCs and LMT motors may be considered, ESCs with a maximum continuous current of 400A, and higher-efficiency brushless hollow cup motors can theoretically bring better results, but the price has doubled directly. .
Because the author's tire was broken, the BSR tire from Haitao just arrived, so I quickly replaced it.
I bought a BSR C8034 hardness. This official website is marked as a speed tire, which is very suitable for running extremely fast. The current F1 fastest record is this model.
Sponge tires are not easy to puncture, and there is no need to wrap fishing lines with hot melt tires like some domestic players, and the damage to sponge tires does not affect the overall use. Even if the tires have problems at high speeds, the probability of rescue is higher than that of hot melt tires. The disadvantage is that it is a bit expensive, about 600 for a car.
Much lighter than stock tires and larger diameter, 105mm.
In the end, I chose an EC8 plug and an 8mm bullet, which is almost the thickest at present, and can withstand higher currents. The capacitor of the ESC adopts a detachable mode, which can be used to compare the effect of the capacitor. Last time I reversed the positive and negative poles of the capacitor. When the 3S battery was charging, the capacitor was only hot, and then the multimeter measured 40A of current and input it to the capacitor. Later, I replaced the Grignard battery, which directly sparked and fused, and the contact part of the 5mm plug melted. A little, scary. Later I bought a new one and re-soldered it.
Because the fixed position of Hobbywing MAX5 is a little out, the right side of the car shell will go out a little, the car shell touches the right rear wheel, and a groove is ground, but this does not affect the use, and the car shell must be tightly attached with tape in the future. on the chassis.
Revamped front and rear spoilers.
After changing to 105mm BSR tires, the side of the front shovel close to the tire needs to be shortened, otherwise it will touch the tire. After that, I will consider removing the front shovel like foreigners. Domestic roads are not very suitable for running extreme speed. Many people go to test roads with few straight cars. Generally, more than 400 meters is enough, and foreign countries are relatively better. The author has a closed road with a length of more than 600 meters and a width of 28 meters.
In general, the ARRMA limitless car is a very niche car, but the manufacturer still sells it, the price is moderate, and the appearance is very handsome. The shortcomings are also very obvious. The quality control of the whole vehicle is poor, and the virtual position is very large. For this kind of extreme speed car, the large virtual position, the higher the speed, the more unstable it is. You can only wait for third-party upgrades to let the virtual position Get smaller.