cruzmissile

Here are the photos of my two heat sinks.

bdavison

My Feedback: (1)

grosporina

True, Amperage is what makes the motor work, but Voltage is what allows that motor to pull amps. The more Voltage you have, the more amps it can pull at one time.

Amperage is current, Voltage is the pressure.
With lipos, we also refer to amperage as the "capacity" of the battery. Or how much current "juice"it can hold.

Example: a 7.4V 2000mah battery. LOTS of available "juice", but it can only send it out slowly.
Example: a 11.1V 480mah battery, Not much available "juice", but it can send it out fast.

Think of a battery like a pump. It can do two things.
Move an amount of fluid (amperage)
Apply a certain amount of pressure to the fluid(volts)

Ideally we want lots of "juice" and we also want to be able to allow the motor to pull it fast. Problem is weight goes up as we get both. So you have to find the best option for your application.

grosporina

I know, I covered this back in 1st year university, or maybe I knew but forgot.
The thing is, the NiMh that came with the heli is 7.2V, 650 mAh, and the Lipo 2 cel I was looking at is 7.4V 850 mAh so I thought voltage and capacity(I don't mean current here) would be good, the weight would be just over half, and the only question would be whether the peak current supported by the LiPo cels was high enough. (ie: maybe at high torques the motor's drawing 3 amps but the Lipos can only support 2 amps without overheating). I had heard that different LiPos of similar rating (V and mAh) might support different peak currents.
mAh is millam-hours, right?, so doesn't it roughly translate into endurance if you assume voltage and current draw are kept constant ignoring that the drop-off when the battery discharges completely is not ideally sharp.

avatar71

I wanted to take a moment to commment on the customer support that Horizon Hobby has on this product. I bought one of the early release Blades some months ago. It was ok but developed some problems over time. Long story short... after two returns to Horizon Hobby, they replaced the WHOLE THING with a brand new one. They even replaced my aerobatics kit too. Not a single cost to me what so ever. I am amazed with their level of customer commitment. I will continue to buy Horizon Hobby products!!! Thanks guys!

bdavison

My Feedback: (1)

grosporina

There's only a .2V difference between those batteries. Not enough to make a difference. Basically it might run longer, but it will provide about the same amount of raw power. If you want more raw power, you have to up the voltage.

With NiMH batteries the drop off is sharp....it's running fine, then blam....its dead.

With the aerobatic kit, the heli needs more voltage. Anyone that has flown the aerobatic upgrades on the stock battery will tell you the heli will barely get airborne. That low voltage just doesnt have the umph it needs to spin the symmetrical blades fast enough to produce enough lift to counteract the heli's weight.

Motors are electrically stupid. They will pull as much as you can give them to the point where they will literally kill themselves by overfeeding on the juice. Take a stock tail motor....shove it on a 11.1V battery all by itself. It will try to devour everything the battery can give it till it runs so fast and hard that it burns itself out. Dumb motor. They will also try to pull what they need to accomplish their task, if it needs 11.1V its gonna try to get it, if it cant get it, it uses what it can with the degraded performance.

With the 11.1V 1250mah lipo, at full charge it will hold close to 12.40V. At about 25min into flight my lipo hits about 11.26V and I start losing available power, at 28min the lipo reaches 11.16V and its coming down...whether I like it or not, but it still has enough power to do a nice gentle landing and have full control. If you try going below 11.16V it will barely get airborne, and stability decreases alot. The gyro will start doing funny things and you will lose some tail stability.

Lipos have many different ratings. 11.1 V 1250mah = 11.1V 1.25A battery. Meaning you can charge it at 1250mah or 1.25A per hour max. mah = milliamps per hour. They also have a discharge rating. Most high quality lipos have around 10A normal discharge rate, with a 16A burst rate. This means that the battery is able to allow something to suck 10A continous from the battery without heat buildup, and 16A for short periods of time.

thecheatscalc

nice decription on motors... but if it feeds so much why doesn't it get fatter?

bdavison

My Feedback: (1)

Its all calorie burn...It exercises so much, it burns them all off.

grosporina

Gotcha. Maybe I'll just buy another NiMh to keep me going while I'm still learning. I'm only just confident with tail-in hovering, so aerobatics are a long way off. Really all I need right now is more flight time, not better performance.
You sure mAh is milli-amps _per_ hour though?

Jet Jaguar

Actually the stock nimh is a 9.6v 650mah, so if you use the 7.4v lipo. there is a considerable drop in voltage. i was never able to do anything with a 7.4 except hover low and slow. 11.1v lipo is where it's at by far. And Futura, i will see if rob will order some of the venom fireballs tomorrow, we should be placing an order soon with venom racing. and as far as flight time with the fireball motor, with the stock nimh, i would get about 10minutes, and with a 860lipo a little more, and with a 1320 about 20 plus depending on the way i'm flying.

grosporina

Oh crap.. I don't know where I got the idea the stock NiMh was 7.2V, ok I see now that the 2 cel lipo is no good. Some weird mental block had me thinking the voltages were close.

Jet Jaguar

Ok, so i just downloaded a new video from the ms composit czech site of the ms230 bell hiller unit being used on a heli the same size as the blade and let me say. WOW! This guy was doing tic tocs 3 or 4 feet off the ground. this thing performs just like a larger size heli. i can't wait to get this unit, but i am having a hard time finding the unit as a whole piece. I think you have to order everything seperate. but i emailed ms composit usa site, and hopefully will here something soon. if anyone knows anything please drop me a line.

mustangflyboy

My Feedback: (2)

jet jag. I would like to see the video my address is "[email protected]" . Thanks
I have had mine inverted once successfully with a quick rotation back to up right but the second try didn't turn out so pretty...... Nose dive. I wish this thing could rotate as fast as my simulator.

Jet Jaguar

Yes it would be very nice to have the blade flip and roll as quick as the Dominion 90 on G3. But that is wishfull thinking for $220's though. But for the price the blade is a rock solid flyer, except for the inverted thing.

bdavison

My Feedback: (1)

Yes it is milliamps per hour...sometimes referred to as milliamp hours...etc.

Basically it means that it can produce that amperage for a period of 1 hour.
Example. A 1000mah battery can produce a constant 1A(1000mA) current for 1 hour.
You can split amps up and such......

Example. You can take a 1000mah battery and make it produce a constant 2A current for 30 min.
or 4A for 15min or 8A for 7.5min....did you catch that?

So why cant you pull 50,000A really fast....well because the chemical properties of the battery wont allow that fast a transfer of current without generating heat.....which is why our lipos get warm when we suck lots of juice from them. This is also where "discharge" rate comes into play. This tells us how much current we can pull from the battery before it starts losing current as heat.

So if you know what the current draw is on your system. You can figure out what mAh battery you need to attain the flight time you want.

So I know what your thinking. Most brushless motors draw 8-10A, how are people getting 25min out of a 730mah battery?....well simple......we dont fly around at full throttle all the time. This is where piloting comes into play....Learn how to manage your available power, and you can increase your flight times simply by conservation.

50nickles

im kinda new to helis but am flying atleast 3 times a day if i can....started doing rolls and loops. then moved in my flybar weights all he way in and went for a roll. once i hit negative pitch my heli fell appart. the only thing i can think of was that one of my blade grips broke due to presure? i have no clue! has this happend to anybody other than me?

a 150 foot tail drop will mess yur sh.t up pretty good!

futura

....boom strike?[:@]

bdavison

My Feedback: (1)

Thats what Im thinking too....boom strike. I havent experienced a boom strike yet, but Ive got my head stiffened up pretty well.

Youve got to fly it smoothly...dont yank on anything. Pulling rapid back cyclic can cause a boom strike. Performing it backwards will prevent it.

Jet Jaguar

the only time i've experienced a boom strike is by holding the heli and repeatedly going from full positive to full negative several times in a row for about thirty seconds. Why do this you ask. Strength testing the head unit, and seeing how much the head can take. i would rather do this in a controlled enviroment than 30 40 50 feet in the air. Your blades could have also been out of tracking which caused them to become closer to the boom when you threw it into negative pitch. Or to much slop in the head unit causing the strike. Or it could have been a loose part, loose link, and some part that was not in alignment. None the less sorry for the loss. luckilythe parts are not too expensive. Good luck on your next invert. And i'm glad to see people starting to get these things inverted and posting on here.

tomcatt51

Jet Jaguar, Wish I could tell you I mow the lawn with it inverted but I'm still working on the upright stuff. Tom

Jet Jaguar

Tis a hard thing to do with a blade, but even though i crash it most of the time when i try to get it inverted. i try try again. eventully i'll either get good at it or buy a better heli.

ljrt

Question about charging Li-Po batteries

I was charging my 1320Mah TP and had an emergency to take care of. I didn't want to leave the battery on the charger while I was gone so I had to disconnect it mid charge. Do I hook it up to the heli and then recharge or just put back on charger to finish charging?
Thanks for your reply.

cruzmissile

Lipo's don't aquire any memory so you can disconnect in the middle of a charge, come back and finish the charging process. It won't hurt it at all.

Sir Fliesalot

My Feedback: (2)

Check your chargers manual. The Astroflight 109 manual says that if the voltage is under 4.15v per cell then you can safely put it back on charge.

Wanny07

I want to start trying figure 8's. Right now my "gain" is turned all the way up, should I turn it down to do figure 8's? Or should I leave it where it is?

Rennster

I was wondering about the play on the blade grips. I did the reverse-the-washers-fix and I notice a bit of side to side play when I tug on the blade grips outward.