raz54

Which brush less motor would you suggest for going in a Reef Racer with a 6 cell? Would any of these work? I'm wanting to gain 5 + mph.

http://www2.towerhobbies.com/cgi-bin...?&I=LXJFY5&P=7
http://www2.towerhobbies.com/cgi-bin...?&I=LXHAJ0&P=7
http://www2.towerhobbies.com/cgi-bin...?&I=LXHAH8&P=7
http://www2.towerhobbies.com/cgi-bin...?&I=LXHAH9&P=7

Gojira

ive herd that the mamba motors dont work well in boats but the esc is fine ,i would look on ebay for a motor ,you should try to get a mega 400 size bl or if you want the smaller dia motor go for a hacker b20 series

raz54

After talking to a tech at Castle Creations I went ahead and ordered the motor/esc combo from TH. Even though it's made for cars the tech said it should make a small boat fly plus it's designed to run on 1100 mAh NiMh packs just like mine. His only concern was if the boat takes too long to plane the esc may not handle it. After telling him it's on plane in less than a second he said it should work fine. I'll post the results next week in case any one else wants to hop-up a reef racer or zig zag.

http://www2.towerhobbies.com/cgi-bin...?&I=LXHAH8&P=7

Nitronutt

My Feedback: (2)

Give me the prop pitch, battery voltage, pinion & spur teeth (If it is geared) and I can plug it into a speed calculator that I have to see an approx top speed for you.

raz54

The prop is 25 mm (1 inch) and pitch is 1.58, 7.2 volts. motor KV is 4200, direct drive.

Nitronutt

My Feedback: (2)

If the pitch is 1.58 inches (40.132 mm) Then your top speed should be 28mph. If the pitch is 25mm, then top speed would be 17mph. Loaded engine RPM would be 24,797.

These figures take a motor efficiency of 82% (Brushless motors usually have efficiency ratings between 80-86%), and also a prop slippage factor of 25% (Typical of a mono hull).

Go up 1 cell to 8.4v and the numbers go to: 32mph & 20mph respectively. 3 Cell lipo (11.1v) = 43 & 27.

32mph in a boat that small is probably not controllable (AKA nearly flying!). Let us know how it turns out!

raz54

The numbers I gave you are from TH parts page for the RR so they should be right. 28 mph is fast for a little boat. Right now it turns on a dime but at that speed it may flip, at least it will self right if it does. Should make for some exciting boating even at 17 mph cause right now it's about 12 mph. The radar gun I got is very accurate so I'll let you know the speed with a stock motor then with the BL. Hopefully your numbers will be close. Thanks

wallstrookie

Pleaseeeeeee put up a video of this.

hahaha this should be awesome. i wanted to do this to my reef racer but i'm gonna wait to see the results first.

Thanks for being the guinea pig.

raz54

First test run, all stock motor and esc and prop, 11 mph Got the new BL motor today and have it installed, sure blows a lot more air now. Test results tomorrow on BL motor. I can take a short video on my digital camera but don't know how to post it. I can't even post a picture on this board, for some reason it keeps saying error. Any one know how and where to post one using a Mac?

Nitronutt

My Feedback: (2)

First you need to hit "reply" above the last post in the thread.

Make sure (For the photos) that they are Jpeg files and say "filename.jpg" as most Macs don't append the file extension - you NEED the .jpg at the end. For video, you have to host it somewhere (Like putfile.com for instance) and then link to it. If you are an AOL member, I am pretty sure that you can add it to your own personal web page.

PLEASE keep us updated! I am curious to see how accurate the calculator was!

raz54

Thanks for the info. All my pics do say jpeg but they still won't load here. They load fine on the other boards though. I'll try putfile and hopefully it will work, if not at least I'll get some stills and put those on the other boards and let you know where so see them.

Nitronutt

My Feedback: (2)

they need to say filename.jpg NOT filename.jpeg and you need to hit "reply" or "quote" first. Then, when the new box comes up, type your message, then click "click here to upload!" at the bottom. Go to the hard drive location where the picture is and select it. Click OK and it will upload. Once is says upload complete, click OK and it will take you back to your post. Click OK again and everything should complete. If you still can't get it to work, email me your pictures and I can upload them for you.

P.S. The picture is of a 1:1 42' Fountain Poker Run (95+ mph).

raz54

I tried that and it always says "error". I'll try again later after I test the boat.

CadillacDTS2001

it did that for me you need to load 1 pic at a time then wait till it say finish and klick ok then reload a nother pic ( do it one at a time )

raz54

Well the first test was sure a bummer. It was so slow it didn't even activate the radar gun (10-200 mph). I think the prop is too big. It says 25 mm but measures almost 28 mm. I might try filing it down to 25 mm plus I forgot the esc is set at a low setting. If those don't work I might have to get the higher KV rated motor after all.

hellomynameisdookie

Raz, what batteries are you running?

If you're running the stock batteries that's your problem. The Mamba needs premium cells with premium connectors. You need to get GP1100's, or run lithiums. GP1100's are your best bet. The pack has to be assembled with battery bars, not thin, spot welded tin and use Deans connectors.

If you don't use top quality batteries with the Mamba it'll never work right.

raz54

Would going to the GP1100 really make that much of a difference? Right now it's only going about 8 mph on the stock 1100 NiMh packs. Would those make it gain about 10 mph? Running the motor while holding the boat the motor screams, a lot faster than the 380 motor. Is that because of 'no load' but the battery can't deliver fast enough when there is a load?

hellomynameisdookie

Exactly. The Mamba esc needs big amps to get the motor going under load....amps that cheap batteries can't provide. The motor will rev up very nicely when no load is there, but under load cheap batteries can't keep up with the amp draw of the Mamba and what happens is it bogs, or is known as "cogging".

It's the same way with using the Mamba systems in micro cars/trucks/buggies. GP1100's or lipos are the way to go.

raz54

Does this motor have enough torque to run a boat? Some say yes and now some are saying no. It is supposed ro replace a 380 size motor.

http://www2.towerhobbies.com/cgi-bin...?&I=LXHAH8&P=7

Nitronutt

My Feedback: (2)

Just a note, you can run it up to 12 Cells! Drop the pitch (Not the diameter) of the prop, I'm sure the batteries have something to do with it - but I doubt 10mph. If you do go with a new custom pack, add a cell or 2 (For another 4200 or 8400 rpm!) if you have the space! According to Tower's specs, that motor/esc combo can draw as much as 25 continuous amps. Unless something isn't allowing that much draw (Like the batteries or the wiring).

That motor can spin WAY faster than your stock motor (Which the prop was designed for), so drop the pitch with a new prop & give the engine more of a mechanical advantage against the water, thus allowing it to spool up higher (into the power band).

raz54

I have some new 7 cell packs ordered, gp1100's so I'll try those. I can't find any one that sells a 25 mm prop so I may be stuck with the stock one. I did talk to another tech at CC and he said the boat should be a lot faster than it was with a 380 motor. He said the batteries are probably the cause so I'll see.

raz54

While waiting for my BL motor to come back I tried the new 7 cell packs and still got 11 mph (380 motor), the same as with the 6 cells. That's one thing though about the radar gun, it does not show tenths so with the 6 cell it might have been 11.1 and the 7 cell 11.9? Pretty hard to see that. I'll make this rr go 15 mph yet...lol

Nitronutt

My Feedback: (2)

Have you received your motor back? Any prop expirimentation yet?

raz54

No it hasn't come back yet but it should be here any day. I think I will go with the Mega motor 400 from Hobby Lobby though when I can afford it (after X mas). I think that one will have the torque needed for a boat.

Capgun_Slim

I've just done a search and found this thread. I've been wanting to do this to a reef racer 1 or 2 since I first saw them. Don't give up on this brushless. There are a few things you need to do to make this work. First, get yourself one of these to go along with that mamba sport package. I use it with my 8000kv Mamba. It's a USB Castle Creations brushless ESC programmer. Don't be alarmed, they also work great for the Mamba series brushless motors, as well as their brushless plane ESC's. I'm curious, which sport package did you get, the 4200kv or the 5400kv? The next step up is a 6800kv then the maximum 8000kv. ESC's.

http://www.allerc.com/product_info.p...roducts_id=723

This will program your ESC for the torque and throttle curve as well as several other things. This will also prevent the "Cogging" as someone mentioned above 2. You are really going to need to stop thinking 6 cells. You need 7 or 8 cell packs. Cheap battery packs dot com has these packs. The best would be a 2 or 3 cell lipo pack for this application, but, if your not ready to go there yet, an 8 cell CBP 650 pack would work very well. These motors crave voltage! Don't be afraid to give them what they want. I fly R/C airplanes, which I use brushless on all of them, and I've got the Mamba 8000kv in my RC18T with which I run a 2 and 3 cell lipo in, and it's crazy fast! Please keep this thread going, I know it will work.