Brushless Project - Original Kyosho Landmax 2

[Sedri]

Hey Forum -

I've been reading the RC Monster forum for a while as a guest while looking for information on what to buy for a brushless system, but it finally became time to register and join so I can post a question to the forum!

My starting place is a Kyosho Landmax 2 kit, and I'm looking for input and suggestions on the brushless aspects of the build. I've sold all my nitro motors, kits, transmission and everything on eBay to get ready for the purchase, so when you make suggestions, don't worry about budget - Err, that is, I'm expecting a total of up to $1000. Here are my component guidelines and performance goals I would like to meet:

The car appearance will be kept true-scale, including original wheels and tires (90-92mm diameter tires as opposed to the ~113mm diameter tires of typical 1/8 scale tires), but under the shell, anything goes -
The car will run a 4800maH 4S1P 20C Lipoly battery.
The car will be geared for a top speed of 45-50 mph, as I want to drive it mostly for "parking-lot bashing", including a lot of drifting, full-throttle and hard emf (motor) braking. I want a motor and controller that can put up with A LOT of abuse without overheating, but I also don't want to buy too much motor, one that seldom or never reaches its optimum potential. I've run a Feigao 540XL 6T on 4S with a 9920BK in the Landmax, and the battery (a 3700maH 4S1P 20C) has never gotten warm, the 9920 only rarely warm (40-60 degrees Celcius, usually cooler) and the 540XL (probably 6T or 7T) has never been to hot too keep a finger on it.

With the 540XL, 4S and the 90mm tires, 14/44 gearing gives 40 mph @ 40,000 rpm (convenient, huh?), 16/44 gearing gives ~45 mph, and 18/44 gearing gives 50-52 mph @ 50,000 rpm.

Mike recommended a Lehner 1940/7 on 5S to get huge acceleration with great top speed, but I really want to build around a 4800maH 4S pack.

My question is this:

Go with a 1940 and gear up to 50 mph (a 1940/7 would turn about 33,000 - 35,000 on 4S under load, right?)

Or go with a 1930? A 1930/7 would turn around 45,000 or so under load on 4S.

I wrote Mike about this; he said that for best reliability and power, try to keep a brushless motor under 40,000, but it seems that most of my "parking-lot bashing" would have the 1940 drawing a lot of amps because of the 4S voltage, while a 1930 might draw less amps because the 4S voltage would be more efficient for the 1930 compared to the 1940. I would be concerned about the 1930 running too hot, but with the higher rpm on 4S, I can keep the gearing 14/44 and still get the speed up to 45 - 50 mph by virtue of 1930 turning more rpms on 4S. The problem is, I've read about others in the forum talking about a 540L 7T or 8T Feigao, for example, running terribly hot on 4S. I want to avoid burning up the motor, especially a quality (read expensive!) motor like a Lehner.

One last question: I currently use 540-sized can-clamp mounts, and I love them. Are the Lehner motor cans 540 size - i.e, 36mm in diameter? I scoured the web for dimensions, but I couldn't find anything, not even on the Lehner "Deutch" homepage, mmm.

Thanks in Advance for any Input!

[captain harlock]

First of all, welcome to the forums, Sed.

Well, for the landmax you say you want loads of speed and keep the motor/ controller cool, right?

The RC-Monster heatsink will easily fit the 19 series lehners which are 36mm in diameter.

I would suggest the MGM 16016 controller with either a 1940/5 or 6 turns.
Then, you should find out the ideal gearing to maintain good heat and reach your 50mph speed.

Also, what brand is your lipo?

[BrianG]

FYI: Dimensions for the 19 series are here....

[Sedri]

Brian, Captain Harlock, thanks for the input. I was glad to see the Lehner 19's are standard dimensioned motors; that will simplify mounting.

I noticed that this thread had been read only a few times, and with only two replies, but I think I figured out why! I popped into the "Pictures and Videos" section this afternoon and noticed that there are ZERO posts of onroad cars...apparently, this forum is for trucks, truggies and buggies!

Oh well, it looks like I might be on my own on this Landmax project!

To get clearer info about choosing a motor for my car, I ordered a selection of various tooth pinions from Mike to test gear ratios with a Feigao 540XL 6T motor on 4S in the Landmax. I love the screaming performance of this motor; now I just need to figure out which Lehner is comparable or better in performance.

[crazyjr]

We are more towards MT's than on road, but if you look there are a few onroad projects going on.

and welcome to the forums

[phildogg]

good luck with the project and let us know how it goes. including pics..
phil

[jhautz]

Mike is right about one thing.... The 1940/7 on 5s is ridiculous!! I run that in my emaxx currently and love it.:027:

But you should be able to get simliar speeds with 4s on a 1940/6 or 5. Just not quite the same acceleration and power.