What's the max voltage/motor rpm for a Tango 45-10?

[jrvander]

Hello,

(I posted this on RR as well in case you see the duplicate question)

Got a question for the general e-flight public; is anyone running a Tango45-10 on 8S? Can this be done without ruining the motor due to exceeding the max rated rpm of 25K?

I ask this because I recently tested my 6S setup using an Eagletree data logger and the motor rpm was an average of about 20,000 rpm, give or take a thou depending on the load.

Musings:

The 45-10 is rated at 25,000 max rpm from what I can find. Some sources say it's a 980 kv motor, most others state 1050.

At 6S or 22.2v the no load motor speed is 23K(22.2 x 1050kv/rpm); once a load is applied it drops to about 20-21K, which figures to be about a  drop during flight. If I were to run 8S or 29.6v, the loaded motor speed would be about 26K (29.6v x 1050kv/rpm x .85).

I'm pulling to many amps on 6S and I think another 2 cells would give me better power and longer flights, so I'm wondering if a new motor (around 800kv) is in order or can I continue to use the 45-10. Has anybody run this motor on 8S?

Thanks!

- Jon

Don't confuse your career with your life

[Shuttle RG]

I think the Tango 45-08 is better for 8s and the Tango 45-10 is better for 6s. You didn't state what you are using it in, or your gear ratios. However, I have been running a Tango 45-08 on 6s (Shuttle conversion) for some time and am getting ready to bump up the performance by switching it out for a 45-10. Sorry, I can't directly answer your question, I know someone else will.

[Motions]

The 45-10 is 1050KV so on 8S you'll be at about 28,000RPM. Keep in mind this is at nominal cell voltage so at full charge your likely to be much higher. According to Kontronik's datasheets, this motor has a max RPM of 30,000 so your right around that. It should work fine as long as you gear it right.

I would agree that the 45-08 is a better choice for 8S.

[jrvander]

Sorry, I should have been more specific in my set up description. I'm using the 45-10 in a L14 on 6S with 550mm blades. 6.05 pounds and flies great but flight times are short at 4.5 minutes using about 2900 mAh. Hover current is about 27A, I'm spiking up to 90 amps with some maneuvers and the packs get hot so I want to add a couple of cells.

The pinion is a 13t which works out to 10.6:1 gear ratio and a head speeed of 1900 with my current settings on a Castle HV85. The 14t pinion used too much current and flight times were abysmal.

My 6S packs read 25.2v at full charge but as soon as I place a load on them they quickly drop to nominal 22.2v and down to around 20v under very heavy loads according to the Eagletree. I'm wondering if that 28K rpm that Scott mentioned is subject to the same voltage drop?

Scott, you answered my question when you mentioned gearing it correctly; with 8S packs I would probably have to use a 10t pinion to get the headspeed in range and that tends to chew up main gears pretty easily. I could dial it down with the gov. mode but that decreases efficiency and builds up heat from what I've read.

Some of the specs I found are confusing. Here's Kontronik USA who state the kv is 920 and max rpm is 28.8 (24 cells x 1.2v):
http://www.kontronikusa.com/motors/tango.html

Here's the German site that lists the same info as a 45-09, which I've never heard of before: http://www.kontronik.com/index2e.htm

Thanks!

- Jon

[Motions]

The German site is the actual manufacturer of these motors. The kontronikusa site is the US distributor for Kontronik.

I was under the assumption that you were running this on a L10 because of the 6S setup. This is almost never used on a L14 but you are running 550 blades so it's feasible. I agree you should switch to at least 8S and that will help reduce the current and heating issues. I also agree that the 10T pinion is fairly small but should still work. If you want a bigger pinion, I would switch to a lower KV motor and run 8S. This will also allow you to run 600mm blades on a mild setup if you wanted to in the future.

[jrvander]

Scott,

I know the current trend is towards high voltage setups and alot of people with the L14 are running 10S now with awsome power. I wanted to try 6S just to see if it could be done effectively with a modern 20C pack vs. older higher voltage 12-15C packs and compare their ability to deliver the watts needed to fly. I was starting from the manufacturers recs:

"LOGO 14 Specifications: electric helicopter for 14 - 16 cells or 5S4P / 6S4P LiPoly"

Antiquated info for sure, but I wanted to know how it would fly. I was getting 1720 watts yesterday and flying great because of it's overall lighter weight but it's obvious that I need more volts after seeing the current draw graphed out.

The difference in weight from a stretched L10 running 550mm blades and the L14 with the same blades is about half a pound by my scale so they're resonably comparable. The rex 600 weighs in at a bit over 7lbs. and uses 6S with 600mm blades. It has a huge reduction gear and runs a 1600kv motor. From the graphs I've seen posted it uses a huge amount of current and needs a 4900/5000 mAh pack to get 5 minutes of flight.

I'm going to get a couple of 2S packs and run them in series with my current 6S packs and see where that takes me. I'm also thinking about using a Z30 800 kv motor. Alot of people seem to like the 1110kv version on 6S; the 800 should be suitable for 8S.

- Jon

[Motions]

Like I said, you shouldn't have any problem using 6S on that setup but if the current is getting high, 8S would give you a good power increase and drop the current.

I'm using the Z30-1100 on my L10 and it's the best 6S motor you can get. The Z30-800 should do very nice on an 8S setup.

The 6S on the Trex is nothing more than a marketing scheme to get the cost lower. It's a terrible setup running it like that.