DCRC

I am new to rc helis, and I was wondering if anyone knew the max voltage & amperage a stock Aerohawk can handle?? I would like to use a power supply and a 50 ft. teather to train with. My power supply is 9 volt, and 1300 mAh. Do you think this will burn out my electronics? Any input appreciated!!!

tnd2000

You mean your intended tethered power supply is rated 1300mA and 9V? That is not enough to power for any electric helicopter. Check the supplied battery, what is its nominal volts and rated current (mAh)?. You'll need a power supply with the same voltage and 3x or more current (mA) to get the heli off the ground.

Freakazoid

My Feedback: (1)

I was thinking the same thing, a while ago. But I didnt bother because of the gauge the tether has to be to allow such current. Thick gauge wire times a couple meters means heavy. :P wich is a no go for such a micro. Besides, the drag of the wire on the ground will probably make it tip down alot. Keep that in mind.

And I think hawks have 7 cells, wich makes 8.4v.

tnd2000

You do not need such thick gauge wires. Look at the wires from your Heli that connects to your battery, you should get wires that are the same gauge. The problem is 50 feet of such thin wire has enough resistance to cause significant voltage drop at the current you'll be using. The way around this is your wires need to carry higher voltage then what is required by your heli. Then at your heli's end, you should use a voltage regulator to drop the voltage to meet the heli's requirement.

Ex for an 8.4v heli
Assuming 50 feet of wire has 1 ohm of resistance. Assuming peak current requirement of the heli is 5 amps then your power souce needs to supply 8.4 + 5 + 2 (drop from the regulator) = 15.4 volts and it needs to be able to deliver 5 amps at 15.4 volts.
Finally you need the voltage regular to fix the voltage at 8.4 volts. If you don't do this, you'll risk burning out heli's electronics because the voltage drop across the 50 feet wire will vary depending on the current draw.

garlicbreath

I have experimented with a tether for months now. If you want to use a power supply, it needs to deliver at LEAST 8 amps at 9 volts. Don't use wire smaller than 20guage and use about 10 feet less than you think you need. I ended up with 20 feet. I also ended up using a cheap 7 cell RC car battery. It is so much easier to take this small battery to where I want to fly than bother with a power supply. It still gives me plenty of fly time to have to let the motors cool down and then to break stuff. I have had it with a tether though, I am splurging and getting a triton charger and Li-po's. The tether sounds like a good idea, and it is if your patient, have self control to reset the heli and re-sort the wire constantly, but otherwise just get some more batterys or go lipo. (can you tell I have the patience of a 3 year old on crack!!)

Freakazoid

My Feedback: (1)

7.4v or 11.1v on a motor that normally runs on 8.4v. [&:] I dont think lipo would be a good idea, unless you want to do serious constructing. (Mind the mail motor).

DCRC

garlicbreath,
I have a 12 volt, 8 amp power supply, so your saying i should just bring the voltage down to around 9 and i should be all set? Have you tested this on a aerohawk?? Are you shure my heli can handle this ( I dont have the cash to replace my main board [] )

zeeshan

there is a thread on this website or maybe 2 threads that i have started up on this matter i did it after alot or reasearch. anyway this is all you need a wire 16 gauge a 12 volt battery supply maybe your car battery and a jst connecter the wire is enough resistance it works great i have stooped with rc helicopters but that system is ideal.

Freakazoid

My Feedback: (1)

@zeeshan:
With 250gram micros? [&:]
With those big outdoor luggers, sure, but with a feather that U-bends its blades like crazy when it has to lift 50gramms? Ive never seen a tethered RC heli fly before, but I seriously doubt it can haul a heap of wire along without getting the ball-chain effect.

tnd2000

I use a 50ft 24 gauge tethered power supply. The wire doesn't have to be thick at all.
As I stated before you simply need to regulate the voltage at the Heli. My power source is very high but when it hits the heli, it is fixed at 8V. A 7808 voltage regulator, PNP power transistor and a heat sink or 2 is all you really need. The whole circuit is less then the size of 1"x2" and weights about 1oz.

Freakazoid

My Feedback: (1)

I meant the wire.
Wont the wire drag along the floor and make the heli tip like crazy?

tnd2000

The Lama XRB is also a tethered Heli. Helihobby carries it. And according to Helihobby it holds the all time longest hands off hover at 50+ seconds if I remember correctly.

Freakazoid

My Feedback: (1)

Well, I assume thats with the wire directly undernieth it, and due to the fact that dual headrotor heli's are stable as bricks in cement.

garlicbreath

I tried 24 guage wire, and tested it with a volt meter. Even with 50 feet it only dropped 1 volt from my 13.8 volt supply. Sure, try it if you want, but I won't run 12 volts through my Aerohawk until I have the money for seperates since that will probably be the outcome. Go buy a 7 or 8 cell sub-C pack for RC cars and wire up some connectors. Mine last for a few hours, which is usually more flight time than I can handle in one day, so charging isn't a problem. And of course, if your not careful, or don't pay attention the tether CAN get in the way, but if you read Radds flight guides you will know your supposed to take it slow, and re-set the heli every time you take off, which in this case means sorting the wire out. As a second note, get the most flexible wire you can find, it helps.

Freakazoid

My Feedback: (1)

Like the wire I use to hook my speed400 motors? I still cant believe that wee little 250gr heli wont go ape with all that weight stuck to its belly. [&:]

garlicbreath

Ever wonder what it would be like to fly a Chinook all the time, but then hook up a tank or hummer under it? Must feel strange, but to me it is a challenge, and if I can figure out how to fly within the constraints of a tether, once I unhook it I must be that much farther ahead. Besides, don't we all want to be able to drop something on people with our heli? (ok, don't answer that, I know I am weird!) (sheesh, what am I thinking, what could I possibly drop with a micro, besides a sparrow egg?)