Radio control equipment
When you buy an rc-sailboat, most of the times the radio equipment is not
included. Thus, you also need to buy it separately. On this section, I'm
going to write some words about the radio components and show the
most popular brands and models available on the market.
All sailboats presented on this website use a 2-channel radio control
equipment. It means that it is only possible to control two functions
while the boat is sailing. In the case of sailboats, those two functions
are the rudder steering and the sails adjustment.
The 2-channel radio equipment components follow bellow:
The transmitter and the receiver
The good news is that when you buy a 2-channel radio, the transmitter, the receiver and two standard servos are already included. Thus, you just need to buy the batteries separately (and maybe a special servo for sails control, but I will comment it later, when I talk about servos). The average price of a two-channel radio is about U$ 50.00. The most usual manufacturers and model are shown in the table bellow. Any of them can perfectly be used in a sailboat.
An important detail to pay attention before
you buy the radio equipment is the operational
frequency. Usually 72MHz frequencies have been used for airplanes and you
should avoid using them in a sailboat. The most commonly used frequencies
for boats are 27MHz and 75MHz. Moreover, if two radios with the same
frequency are used at the same time, there will be interference. So, if
you are planning to sail with other people, try to find out which
frequency they have used on their radios and buy a radio with a
different one. The operational frequency of a radio equipment can be
changed, but you will need to buy new crystals and they are not cheap.
Once you have bought the radio, you can make a small modification on the transmitter in order to make
easy the sails
adjustment. The two sticks existent on the transmitter are connected to
small springs which bring them back to the neutral position
(center). It is an important thing for the rudder control because it will keep the
boat in a straight line after a maneuver, but it is not desirable for the
sails adjustment. When we adjust the position of the sails according to
the wind we want that the sails stay in that position. Thus, the sails
adjustment stick should not return to central position, but keep the
position we put it. In order to modify the transmitter, you have to open it
and remove the spring responsible for bringing back the stick to
the central position. Be aware that only the sails adjustment stick (the
one which moves in a vertical way) should be modified. I've done this
modification on both Futaba's Attack 2VR and Hitec's Ranger 2N
transmitters and it is not a difficult operation. I believe it should be
easy on other models as well.
As said before, almost all
two-channel radio equipment comes with two standard servos included.
However, these are simple and weak servos. The rudder steering in an
rc-sailboat do not need a lot of power and the standard servo can be used
without problem. Nevertheless, the wind power upon the sails many
times exceeds the capacity of these servos. Probably it will be possible
to use a standard servo on boats up to about 80 cm long. Even so, it is
possible that the servo hasn't enough power to pull the sails in a heavier
wind. If you intend to own a bigger boat (90 cm, one meter or bigger), you
will have to buy a sail servo (sail winch). There are two kinds of sail
winch: the arm
and the drum
sail winch. The major difference among them is that the arm
winch rotates a maximum of 90° to 145° (depending of the model), while
the drum winch rotates some 360° turns. The choice between one or the
other will depend on the boat that you own and on the space available on
your boat for arm moving (the arm winch needs much more space than the
drum winch). Other details you should examine are the winch speed, stall
torque, dimensions, weight and other specifications related to your boat.
If your intention is competition, you should try to find out which servo
the other skippers on your class have been used. They probably have
already tried a lot of models and have defined which one is the best for
your kind of boat. A table with the specifications and pictures of the
most usual sail winches follows bellow.
|Manufacturer||Model||Speed (no load)||Stall Torque||Drum diameter||Arm lenght||Max. Revolutions||Dimensions||Weight||Min. voltage||Max. voltage|
|RMG||380D||360° at 0.32 sec||21.2 kg.cm (294 oz/in)||32 mm (1.26 in)||xxx||6x360°||79x54x60 mm (3.1x2.1x2.4 in)||168 g (5.9 oz)||3.8 V||8.5 V|
|380HD||360° at 0.32 sec||21.2 kg.cm (294 oz/in)||32 mm (1.26 in)||xxx||6x360°||79x54x60 mm (3.1x2.1x2.4 in)||175 g (6.2 oz)||3.8 V||8.5 V|
|280D||360° at 0.30 sec||11.2 kg.cm (156 oz/in)||26 mm (1.02 in)||xxx||4.8x360°||74x54x59 mm (2.9x2.1x2.3 in)||134 g (4.7 oz)||3.8 V||8.5 V|
|280DL||360° at 0.38 sec||14 kg.cm (194 oz/in)||26 mm (1.02 in)||xxx||7.2x360°||74x54x59 mm (2.9x2.1x2.3 in)||134 g (4.7 oz)||3.8 V||8.5 V|
|Hitec||HS 715BB||60° at 0.19 sec||14.5 kg.cm (201.36 oz/in)||xxx||108 mm (4.25 in)||90°||59x29x52 mm (2.33x1.14x2.05 in)||102 g (3.6 oz)||4.8 V||6 V|
|HS 725BB||360° at 1.3 sec||14.5 kg.cm (201.36 oz/in)||38 mm (1.49 in)||xxx||3.5x360°||59x29x52 mm (2.33x1.14x2.05 in)||110 g (3.9 oz)||4.8 V||6 V|
|HS 815BB||140° at 0.38 sec||24.5 kg.cm (343.01 oz/in)||xxx||108 mm (4.25 in)||140°||66x30x58 mm (2.59x1.18x2.23 in)||152 g (5.6 oz)||4.8 V||6 V|
|* Whirlwind||Atlas||???||???||32 mm (1.26 in)||xxx||6.5x360°||59x23x48 mm (2.32x0.9x1.89 in)||90 g (3.2 oz)||4.8 V||6 V|
|Tensor HS||360° at 0.48 sec||???||32 mm (1.26 in)||xxx||???||???||80 g (2.8 oz)||4.8 V||6 V|
|Futaba||S3801||60° at 0.26 sec||14.0 kg.cm (194 oz/in)||xxx||125 mm (4.92 in)||125°||61x30x51 mm (2.4x1.2x2.0 in)||107 g (3.7 oz)||4.8 V||6 V|
|S3802||60° at 0.56 sec||11.0 kg.cm (153 oz/in)||xxx||125 mm (4.92 in)||140°||46x23x43 mm (1.81x0.9x1.7 in)||73 g (2.6 oz)||4.8 V||6 V|
|S5801||360° at 0.6 sec||7.8 kg.cm (109 oz/in)||42 mm (1.65 in)||xxx||6x360°||46x25x46 mm (1.8x1.0x1.8 in)||83 g (2.9 oz)||6 V||7.2 V|
|Graupner||Regatta||360° at 0.8 sec||8.1 kg.cm (141.6 oz/in)||38 mm (1.49 in)||xxx||5.5x360°||46x23x42 mm (1.81x0.9x1.65 in)||90 g (3.2 oz)||4.8 V||7.2 V|
|Regatta ECO||360° at 1.2 sec||4.6 kg.cm (63.7 oz/in)||25 mm (0.98 in)||xxx||5.5x360°||46x23x42 mm (1.81x0.9x1.65 in)||70 g (2.5 oz)||4.8 V||7.2 V|
|Robbe||SW-1||360° at 1.3 sec||10.1 kg.cm (141.6 oz/in)||38 mm (1.49 in)||xxx||5x360°||59 x29 x52 mm (2.33x1.14x2.05 in)||110 g (3.9 oz)||4.8 V||6 V|
| All specs are
based on a 6V current.
* The Whirlwind winches have been discontinued.