Any input on the Turnigy SK3 Fandrive 3994-850kv

[Tim Strange]

I have seen the Turnigy SK3 Fandrive 3994-850kv mentioned in a couple of other threads as a possibility for 1/8 scale FE power. Just looking for some feedback from anyone that has tried one.

We have a pretty strong showing for nitro 1/8 scale here locally at Evansville IMPBA district 14, so I don't think that I would be able to race a 1/8 scale FE. I would like to try to experiment with an electric conversion any way.

It looks like NAMBA has restricted batteries to 8 cell lipo, which works for me as a starting point since I have 4S packs on hand.

Thanks for any input.

Tim

 

[raptor347]

I watched several of the RCU guys running them at the NWSC. Performance was impressive regardless of price. RCU rules limit the packs to 8S, NAMBA has a 10S limit.

 

[Tim Strange]

Thanks for the reply Brian. I assume that they were running 8S then?

 

[raptor347]

8S and a 57mm max prop diameter.

 

[lohring]

I run 4 4S packs wired to give 29.6 nominal volts (8S) and 10,000 mah. You only need 5,000 mah for two lap records, but the extra packs really help for heat racing. That's more than the current RCU electric rules allow, though. See below.

Lohring Miller

Power and Drive Train:

Motor:
-NEU 1527 1.5Y

Experimental options for 2013
-Scorpion 4035-800
-Turnigy SK3 Fandrive- 3994-850kv

Batteries:
-8S1P configured Lithium Polymer (LiPo) battery(s).
The total capacity of batteries in
the allowed chemistries and configurations shall not exceed a total capacity rating of
6,000 mAH. Only LiPo batteries with a manufacturer’s minimum discharge rate of 30C
constant but no higher than a 65C constant shall be
allowed. There is a maximum
$200.00 msrp per set limit.

Speed Controller:
-Any speed controller may be used as long as it is
a minimum of 150Amps.
-For safety, anti-spark resistors are required on a
ll speed controllers.

Propeller:
-Any propeller may be used up to a maximum of 57MM
diameter

 

[Tim Strange]

Thanks for reposting that info Lohring...your posting on another thread(s) of that info is where I got the idea to try the less expensive SK3. That will allow me to invest in a good ESC and more batteries.

Looking at going with one of the Castle ESC's. I like the Hydra Ice 240A because of the extra Amp capability, but it is limited to 8S. The Hydra Ice2 200A looks good also, and it will allow me to try 10S in the future if I decide to go that route. Either way, they both have data logging built in...a feature I really like. Of course I'll need to do more research on Cap Banks and anti-spark resistors...anything to protect my investment from meltdowns!

One major concern I have, is cooling for the SK3. I was hoping to use the cooling jacket for the Neu 1527. The problem is the SK3 is listed at a 39mm can and the Neu is a 40mm can...just haven't found a 39mm jacket anywhere. Then there is the motor mount...not sure what to use as I don't know what the SK3's bolt spacing is...

Anyway, hope everyone has a safe and happy Holiday!!!

Tim

 

[lohring]

I took a quick look at Hobby King after eating too much turkey and found some new "boat" ESCs. The Hobby King YEP 180A HV might be a good choice, but it's not inexpensive. I've had very good experiences with the Turnigy 120 and 180 Marine ESC's but bad luck with the Aquastar ESCs. The burst rating seems to be key.

It's still hard to beat the Castle ESCs. The data logging is especially valuable. I'd try the new Phoenix Edge Lite 200. I bet it's very similar to their old 200 amp ESC. You would probably need to add water cooling someting like I did with an ICE 100 pictured below.

This is a good style mount. I make similar ones from angle. If you look closely you can see a water jacket made from carbon tube and O-rings sealed with CA on the ends. It uses standard drip irrigation angles CA'd into the tube. Andrew once sold these, but I don't see them on his site. You might try larger cross section o-rings in the Neu water jacket.

Lohring Miller

 

[Tim Strange]

Lohring, I hope you have recouped from your Turkey feast. Just think of it as practice for the Christmas feasts you will have to endure

Yesterday I ordered the SK3 3994-850kv from Hobbyking USA. So I guess now I am committed to this project. I'll need to decide which hull to use...I have Phil Thomas Karelson, 8255, and a T-5, as well as a late 80's build Atlas Van lines (most likely candidate) and an unstarted MLboatworks 1984 Atlas turbine kit to choose from. There is also an Aeromarine Miller American collecting dust.

I have been searching for info on this motor used in a 1/8 scale elsewhere, with not much luck. I did find a nice build thread for a twin EDF jet build using two of these motors and 120mm EDF units. The motor mount holes are apparently 25mm. The builder was very pleased with the quality and power of the motor...but this is the application it was designed for.

I did find one small blurb from someone from RCU suggesting that the NEU 1527 cooling jacket does fit. He also suggested the Castle Hydra ICE 2 200HV ESC I have been eyeballing.

Another possibility for the ESC is the Hefei Swordfish Pro 200 Amp. From what I understand, they seem to be pretty good products...of course I have been known to be wrong sometimes. Of course it doesn't have the data logging capabilities of the Castle controller, but the bonus is that it is $200 less expensive. For now I will wait on the ESC purchase and focus on gathering the other items I'll need.

One question I have is what size bullet connectors to use. My batteries have 5.5mm bullets which I think would be adequate...I'll need to find or make some Y connectors so I can use two 4S packs. So would 5.5mm battery side to 5.5mm ESC side be OK? Also the motor comes with 4mm bullets...Should these be upgraded?

Thanks, Tim

 

[lohring]

I used 5.5 mm bullets on the individual batteries but 8 mm bullets everywhere else. It's probably overkill, but the currents could get around 200 amps even though 100 to 150 is most likely with the RCU rules. Below is the data from our two lap record.

Lohring Miller