RE: 7955 with a Y-Harness?
This is from the Smart Fly website:
We have measured a digital servo, unloaded, drawing 0.6 Amp when kept in continuous motion.
Now this is one digital servo with NO load. If you have 2 servos on a "Y", you are feeding those 2 servos through one standard connector. You have just cut your rated capacity in half, and you now have 1.5 amps rated capacity per servo (because a standard connector is only rated at 3 amps).
With a working servo and NO load, you are already at almost 1/2 of your rated capacity (.6 amps). Imagine how much more current you might use when you start applying an in flight load to the servos. You will easily be over the rated capacity. Will 2 aileron servos be at 6 amps all the time........ No, but during high load maneuvers when you are using a lot of amps momentarily, you will get a big voltage drop and your servos will have less torque. So, right at the time when you need torque the most, you will get voltage drops and have the least amount of torque available.
Here is more info from the Smart Fly website:
We have measured a half volt drop over eighteen inches of 22 gauge wire and one connector at 5.0 amps.
This is the law of physics in play here guys. Voltage drops are always present in our set ups, the trick is to keep these voltage drops to a minimum. You keep the voltage drops to a minimum by using components that are up to the task. A standard connector is capable of supplying current flow to one high torque digital servo. It is not up to the task of supplying current flow to more than one high torque digital servo. You will get excessive voltage drops.
Does this mean that your plane will fall out of the sky...... No, it just means that your servos will have reduced torque. It just means that you will not have the optimum set up.
Many guys are flying planes with matchboxes, "Y"s, and other components and set ups which limit their current flow. The plane will fly this way, just understand that you don't have an optimum set up. You can choose not to have an optimum set up.
Compare this to engine selection. Many guys use cheaper engines that weigh more and don't produce as much power. They saved money though. They could have purchased an engine that weighs less and produces more power, but it costs more. They chose to buy the cheaper engine. Their plane will still fly around with the cheaper engine, but it won't fly as good because it weighs more, and it won't have as much power. They won't have the optimum set up because of the engine they chose to buy.
It's the same thing with how you set up your radio system. There is an optimum way to provide the best current flow, but other ways will work. Other ways just may not be as good. You may have limited current flow. Your plane will still fly, and you can still enjoy the hobby and have fun, but you won't have the optimum set up.
All I have done in this thread is present the facts which should help someone decide how they want to set up their radio system.
You can use "Y"s if you want to, but understand that you will get voltage drops. You will save money this way though, because you won't be purchasing a Power Expander or similar.
If you want to spend the money for an optimum set up, you have that choice as well.
Jim