Please HELP with T600 Outrunners and SkyWing 150A ESCs

[norbique]

Please help me with my intended setup for a (115cm long) twin cat setup.
I've got the motors, two Turnigy T600 1400KV outrunner motors.
Intended ESCs are 2 SkyWing 150A ESCs, which I'm gonna watercool, waterproof and add Capactior banks to.
Battery is either 7S or 8S 2P A123 Life batts, depending on how much Series the ESCs can take. I've heard rumors these ESCs are built with 30V Mosfets, which would be quite marginal with the 8S Life (28.8V fresh charged). If anyone can comment on these ESCs please do so. I need all the help I can get. Thank you!

I also wanted to ask those more experienced about the Timing and Switching frequency setup of the ESCs. Please correct me if I'm wrong but I think the more magnet poles a motor has the higher degrees timing I must choose.

The T600 has 8 Magnet poles, and the ESC can be set up to either 1*, 7*, 15* or 30* (* being degrees). What's the advantage/disadvantage of both?
Is my thinking right to set it up to 15*?

On switching frequency, should I stay at 8KHz as that's the default, or go to 16KHz which is intended for higher RPM higher magnet pole count motors? (as stated in the ESC manual)
I know a lot of question at a sudden, but feel free to say/write your thoughts here.
Thanks in advance!

[siberianhusky]

Be better if you could get the voltage in the low 20's, thats a lot of rpm, just over 40 000! Thats not exactly high dollar stuff you have there I don't think it would live for long at all in a SAW rpm setup.
No idea about timing for outrunners.

[norbique]

Thanks for the reply! But I'm speaking of A123 cells, not Lipos. So no 40K RPM but only 37K if I go with the 8S setup, or 32K RPM if I go with the 7S setup.

I just saw a video on HK website about their SS 190-200A ESCs. The guy tested the ESC with a 1100KV version of this T600 motor and he said best performance was at 16KHz setting and 30 degrees timing... Interesting to know.
http://www.hobbyking.com/hobbyking/s...2b370cfdf83973

[ray schrauwen]

Thank you! That is nice to know. I was running mine @ 8Khz & 15* timing. I'll try your suggestions.

[norbique]

It's not my suggestion! :) Just take a look at the video link. At the end the guy says 16KHz and 30 degrees worked best...

[norbique]

I listed my planned setup for easier overview:

2x Turnigy T600 1400kv outrunners. [bought]
2s SkyWing 150A ESC off fleabay. [NOT bought yet]
2x 7S2P A123 (voltage equal to 6S lipo) batteries [NOT bought yet]
2x x447 props. (R/L) [bought]

My question is will the 150A ESCs suffice, and will the 2P A123 battery configuration be able to handle the current needed by the motor? The A123 Datasheet says 70A continuous, x2 = 140A Continuous for the 2P A123 setup.

Is it marginal? Anyone using the same motor on 6S LIPO perhaps?

I also plan to add water-cooling blocks to the ESCs and waterproof them. And add 5000uF capacitor banks to them.

I calculated the RTR weight of the boat to be somewhere between 6-6.5kg (~13-15 pounds) if this helps.

[Fluid]

I have no experience with those motors, but from the specs they may work as planned, although marginally. Ditto the ESCs, you will have to start carefully to make sure you don't over-amp your systems. A lot will depend on the boat's design and on how it runs - if it runs freely then good, if it runs wet then all bets are off.

Based on the battery capacity, 120 amps maximum would be good. With both motors runing that's close to 5000 watts, enough for most cats. Prop choice will be very important to keep from burning down. I would start with Graupner K45 props, they can give good performance but are snmaller and less efficient than Octura metal props. That gives you a safety margin. If the K45 props are too small, then try the x447b props. Go carefully at first, don't run for over one minute without bringing in the boat and checking temps. If safe, go another minute and check.

[norbique]

Thanks Jay!

I must buy some K45 props then. I'd better be on the safe side and start with smaller diameter props.

I still have to polish the Octura props, should I also de-tongue them slightly?

What determines if a cat runs wet? Only the weight/size? Or the shape of the sponsons as well?

Since I haven't bough the ESCs do you suggest I go with 200A instead of the 150A, just to be safe?

[NativePaul]

What determines if a cat runs wet? Only the weight/size? Or the shape of the sponsons as well?

As long as you have enough power to weight ratio to get up on the plane its mainly the CoG and strut angle that determine how wet or loose you run. The tunnel and sponsons play there part too of course but they are the constants and CoG and strut are the variables that you adjust with.

[norbique]

Thanks Paul!

[RayR]

Norbert,

I run twin 1400kv T600's in an older 43" MHZ cat. 6S LiPo, Turnigy 120 Speedo's turning 447's. After a 6 lap (1 mile) run it comes in with the following temps. Motors 125, Speedo's 110, batteries 105. Timing is 8 khz @15 degrees. I wouldn't recommend the 120 speedo's for this combo, while they are working fine, I am running without much margin for error.

All the best,

Ray

[TotalPackage]

I just ran this motor today on 6s in a parther 40 inch mono and a k51 on an 100 amp elf hobby esc that I have no idea the timing or how to set it. It auto set itself. The esc and motor came back in luke warm and I mean luke. The esc was ice cold im being honest. Now mind u I didnt do six laps but I must have done 16 saw passes.

[TotalPackage]

Norbert,

I run twin 1400kv T600's in an older 43" MHZ cat. 6S LiPo, Turnigy 120 Speedo's turning 447's. After a 6 lap (1 mile) run it comes in with the following temps. Motors 125, Speedo's 110, batteries 105. Timing is 8 khz @15 degrees. I wouldn't recommend the 120 speedo's for this combo, while they are working fine, I am running without much margin for error.

All the best,

Ray

What kind of speeds you getting with that set up

[norbique]

FINALLY!!!! :)
This is the news I was hoping for. And two people at once.
I wanted exact data, and I got it now.

Thanks Ray and TotalPackage!

I was a bit unsure whether the 150A Speedos would do the job. Now I'm more confident they will, especially after the mods!

Ray, are you cooling the motor somehow? OR the ESC for that matter?

[RayR]

FINALLY!!!! :)
This is the news I was hoping for. And two people at once.
I wanted exact data, and I got it now.

Thanks Ray and TotalPackage!

I was a bit unsure whether the 150A Speedos would do the job. Now I'm more confident they will, especially after the mods!

Ray, are you cooling the motor somehow? OR the ESC for that matter?

I am cooling the ESC's but not cooling the motors. The MHZ hull is roomy with plently of air inside to dissipate the motor heat.

All the best,

Ray