Outboard motor choice

[HOTWATER]

Good deal...love the Leecrafts!

[lohring]

The CG is the same as the nitro boats - 10 1/2 to 11 inches from the transom. Some racers ran the CG back as far as 9" from the transom, but I never got that to work. The nitro boats carry a lot of lead on the sponson tips. With an electric you can solve this easily with battery placement.

Lohring Miller

[HOTWATER]

Brian Buaas tried a higher Kv motor. The boat was undriveable. We also wanted to duplicate nitro motor's rpm and use similar props. You could probably run a small prop with a higher Kv motor, but it might take a different boat. I have years of experience with the Leecraft XT-460. That setup is at the upper edge of what the boat will handle. The very best drivers (not me) can heat race that hull at a little over 60 mph top speed. This setup can match or exceed that with a modified 1450 prop. Below is a picture of the layout.

Lohring Miller

[ATTACH=CONFIG]59185[/ATTACH]

Lohring, with the batts up front like that, where does the CofG fall? Just curious.....

-Kent

[kendt]

Very cool. I guess im thinking about monos or cats when I think of higher kv,s. I understood the sweetspot to be somewhere between 30 to 35000 rpms. If you are trying to keep it on par with nitros it would make sense.Mine will be for a hotshot 45 hull and i have no clue what kind of power it will handle. Im still trying to gather info on bringing the hull up to snuff in that area but have come up empty.I was going to try to avoid 6s due to the cost of the batteries however i have since learned that the higher voltage setups are more efficient and a bit easier on the esc etc so i am now re thinking my approach

[lohring]

Brian Buaas tried a higher Kv motor. The boat was undriveable. We also wanted to duplicate nitro motor's rpm and use similar props. You could probably run a small prop with a higher Kv motor, but it might take a different boat. I have years of experience with the Leecraft XT-460. That setup is at the upper edge of what the boat will handle. The very best drivers (not me) can heat race that hull at a little over 60 mph top speed. This setup can match or exceed that with a modified 1450 prop. Below is a picture of the layout.

Lohring Miller

P1010084.jpg

[1truckerdan]

A 1100kv motor would be 24,420 rpm on 6s

[kendt]

I did read that post. Isn't the 1100kv a bit low. Im no expert thats for sure it just seems most recommend in the 14-1600kv range.

[lohring]

From this thread on International Waters:

We are looking for a low cost replacement for 7.5 nitro engines. The first test was on Leecraft XT-460 tunnels. After some trials with inexpensive motors that didn't hold up we settled on:

Scorpion HK 4025 1100 KV motor http://www.innov8tiv...products_id=569
Turnigy 180 amp speed control http://www.hobbyking...?idProduct=8937
6S 5000 40 or 45C batteries http://www.hobbyking...idProduct=14616
Hyperformance 7.5 outboard conversion kit http://hyperprod.biz...ersion_kit.html

That power plant costs around $400 with the motor at $160. Still, the cost is in line with nitro power heads. We used an old K&B lower unit. The performance of Brian's boat is better than a mod engine powered XT-460 with both electric and nitro boats running an Octura 1450 prop. You just need to run the prop a lot shallower than with a nitro engine. Bigger props torque the sponson into the water, flipping the boat. Outrunner motors worried us since they aren't as easy to water cool as inrunners, but that doesn't seem to be a problem with outboards. The next test will be an inboard setup in a Sport 40.

Lohring Miller

[kendt]

Well thats good to know. If i am unable to cancel I will go that route. The hobbywing 180 would do the trick wouldn't it??

[Darin Jordan]

Or... you can just run it on 3S... It's perfect for that... 3S2P would be the same number of cells purchased as 6S1P, and, while you would be drawing more amps, you'd have longer runtime... Would need a GOOD ESC, however... most likely.

You would REALLY be better of with the RIGHT motor in the 1300-1400 KV range on 6s, or an 1800-2200 KV motor on 4S...

[kendt]

I sent a message to the seller to ask if I can cancel. Hopefully he'll play nice...lol

[kendt]

Hmm well thats not good...lol would it be the same case with that motor in a 32 in mono or worse??

[bbill1]

Well i wont be racing it so thats not a worry. I wanted to go down to 4s because 6s batteries are just too much money. If it doesnt work out ill sell it and try something else. for 119.00 its not a huge loss.

You misunderstand my statement. With a 2650kv motor, you won't be running it more than about two minutes tops before you start burning up stuff. And that is on 4s. That is basically a SAW motor.

If it doesnt work out ill sell it and try something else.

If it doesn't work out you probably won't be able to sell it. cause it or the esc, or both will be trashed.

[kendt]

Well i wont be racing it so thats not a worry. I wanted to go down to 4s because 6s batteries are just too much money. If it doesnt work out ill sell it and try something else. for 119.00 its not a huge loss.

[bbill1]

Wow I just saw a video of a guy using the same motor on a 36in wood tunnel, 5s and the thing was flying.

Yeah but are trying to race it, just play around, or do saw runs and bring it right back in in 30 seconds...