Kmot

My Feedback: (24)

I bought an airboat off eBay because it looked good in the photos. What I got was not quite the same as the picture in the advert.

Turns out it has a very shallow well for the electronics, a 6 cell pack will be hard to fit along with a Rx, ESC, and servo. This is limitied me to what I can power it with. From recent lessons in electric boating I have learned that batteries and motors get hot and I don't want to melt a hole in the ABS.

Does anyone else have this same electric airboat that was on eBay? Or another type and can give some experience with the type of powerplant and successes and pitfalls?

Thanks!

TERBObob

My Feedback: (21)

Wellllll .... you could always pull that motor off there and replace with a small nitro one ?!
Would give ya LOTS of power then .
Or , you could also put a water cooling ring ( like they sell on EBAY ) for the electric motors and put the water pickup thru the bottom and out the side ?
The battery pack ? I would probably go and wrap that baby up in whatever I could fir into the hole with it .

pro27

If this is the one I'm thinking of, I may have seen it on ebay a while back, but haven't seen it for a while. My interest was peaked simply 'cause it looked neat. Is this the one from a place in Canada?

I'm sure there are ways around any problems.
As far as fitting things in, you may have to look into going to some smaller electronics. Instead of a standard servo, you may have to go with a mini size (not micro) which is the next step smaller than a standard servo.
For the ESC, not knowing which one you have or are thinking of, there are some pretty small ones available out there that will work. I have used GM esc's in my electric touring cars (ya, ya, ya, a guy has to have a hobby you know. But boats are still my passion). A GM 3 is very small compared to most, about 1" x 1.25". I got mine from my lhs for around $50. They are available through Horizon Hobby Distributors and is an excellent esc.

The heat from the battery should not pose a problem. Depending on the motor used, you would have to pump out a steady 25-30 amps to really heat up the pack. Stock (23-27 turn) motors MIGHT make the battery warm, as they seldom exceed 20 amps of current draw.
Heating up the motor should not pose any problems either. I race my touring car indoors in 5 and 10 minute heat races, and my stock motor barely gets warm. This, in an enclosed car body with very little air circulation around the motor. The motor on your airboat is fully exposed to moving air all the time. Big difference. If you want to feel safer, there are many types of heat sinks that you can attach to the motor can to help draw off heat.
Check out a good lhs that deals alot with electric touring cars or off road trucks. They should be able to help you out with any of these items.

Kmot

My Feedback: (24)

Yup, it's the one from Canada!

Motors in cars and trucks are a totally different ballgame then when you load them up with a prop. Same as taking your car motor and car ESC and putting them into a boat. Much harder on them due to the increased load put on them.

A micro servo won't turn the rudder against the blast of air. Will have to use a standard or heavy duty. I am thinking of going with an inline gear system on an electric aircraft capable motor.

I just wanted to know what others with an electric airboat have actually used. I know of one other guy who came into a boat baord complaining of melting holes in his ABS from overheated batteries by using a car 540 motor on a 7x6 prop.

I'll figure it out. Just wanted to see what else was done like I said.

pro27

I have run car motors and esc's in my sport and race boats with no problems in two years.
Most also use Hitec ms-81G servos for rudder. A very reliable servo for me, even with the force of water against the rudder blade. Others also use them in their competition boats.
My set-ups include 4 cell- mod motor, 6 cell- stock motor, 6 cell-mod motor, 8 cell mod motor.
Granted, inboards have run durations of about 3-3 1/2 minutes using 3000/3300 cells, but my mod motor set-ups run anywhere from 30-50 amps at load.
All my hulls are plastic, and haven't melted any yet.

TERBObob

My Feedback: (21)

Kmot ,
I know what you are saying . When I bought my 9 yr old , his GP WILDCAT twin 540 cat , and after using it for a while ( changing out battery packs consecutively ) , it DID melt part of the top of cowl. ( caused from the motors )
The motors WERE indeed HOT and the packs warm . I remedied that problem by changing the electric over to nitro and its now got a Megatech M-16 - with pull starter in her .
Oh , I first watercooled the motors , but was not happy with the batteries lasting such a short period of time ( actually , I should say , my sons were not happy ) and I also feared the batteries melting thru. ( was running twin 6 cells parallel )
I realize this is a regular boat propped hull , but the thought is basically the same .
AS PRO said , there is always ways around problems , but its just how "stuck" you are , on doing it a certain way .
Like I previously stated , I would change it over to nitro myself ( don;t really care for those short lived battery packs and yep , I had a Rooster ESC toast on me after getting a little drop of water on it and with THAT kind of monies , I said enough was enough . )

pro27

That thing would be a missle with a good .10 - .15.
Modifying the mount looks like it would be do-able.
What is the largest size prop that will fit in the shroud?

Do you have an E address for the mfg? I don't see it on ebay anymore.

Kmot

My Feedback: (24)

The seller was a loser. After a month of waiting, e-mailing, no respose I then started the process of filing claims against him. Filed a claim with eBay; Paypal; etc. Then he finally responded, made some lame excuse and shipped me the airboat. The electronics well on the one I received is half as deep as the one that he showed in the picture of the auction. It is very cheaply made. The rudder is not on bearings or even bushings so it has a tremendous amount of drag. That Hitec "micro" servo has 36 oz in of torque so it might work but I think I really need to modify the rudder to have less drag. The rudder will also need reinforcement like abs strips or something. It is really a cheap and crappy airboat kit for the money. I think a nitro motor would just tear it apart. I also want to run it electric for the quiet factor and the fact I can run it anywhere. Nitro power is severely restricted where I live.

pro27

Thanks for the input on the boat and seller.

Any other way we can try to help on suggestions to get it strengthened up?

I understand what you said about the rudder. Maybe a vertical piece to strengthen it top to bottom, placed at the front of the rudder. Also 1 or 2 pieces horizontally to add stiffness that way.The reinforcement pieces probably don't need to be that thick or wide, 1/4" maybe?

Can't tell from the pic how the hinge points are set up for the rudder. Maybe just some alum or brass tubing bushings into the plastic, and a piece of brass rod or music wire attached to the rudder to act as the hinge post instead of the original setup. Just a suggestion.

TERBObob

My Feedback: (21)

Without knowing the seller or having seen this boat before , would I be out of line if I asked you how much you paid for it ?
Also , PRO's idea about the piano wire is also what I was thinking . That servo at 36 ounc torque , would be extremely questionable if that thing pushes any decent amount of air . Especially if it not BB and metal geared .
From the picture , the boat itself doesn't look all that bad , but I also have a slight disliking to electric , (sorry - just don;t really care for them )
If you could , show us a pic or two of the back ( transom ) area so we can maybe assist better .

pro27

When I saw this on ebay, it was a BIN for around $60. I hope it wasn't much more than that. At the time it seemed worth the money. I don't know if I'm glad or not that I didn't get one. The pictures on the auction did make it look pretty sharp though.

Fluid

Kmot: It looks like there may room for a servo in the open well under the motor mount. While mounting a servo in the open may seem like an invitation to disaster, it can be done with good reliability. Use a standard size $10 servo laying on its side, glued in with silicone glue. Waterproof the servo first by coating all seams and screws and wire exits with silicone. Pack the exit shaft under the servo arm with vaseline. This will keep the servo operating fine when wet - just seal the control wires well where they pass into the sealed radio box.

Melting the bottom of the hull with hot batteries is only a risk when the bottom of the boat is out of the water. Melting the hatch cover is more of an issue, but some insulation under the hatch can help. The "fuzzy" part of Velcro can be stuck under the hatch above the cells to give some insulation.

I agree that a gear drive will be needed for this boat if decent performance and run time is desired. You can spin a three-bladed prop with more pitch and gain a low of thrust while reducing the load on the motor and battery temperature. You will also be able to run a more powerful motor for less resistance and possibly longer run times. While the shroud is a great safety idea, it will cause a lot of drag and is not of the correct design to improve thrust.

Kmot

My Feedback: (24)

Hey Guys,

The boat was IIRC $65 USD plus shipping from Canada so it cost around $80.

Fluid, I like the idea of mounting a servo under the engine stand.

Anyways, it is a project that is far down the list. I have many more items to complete before I get to it.

BTW, that shroud is attched to the hull with one #4 sheetmetal screw on each side. And the rudder is attched to the shroud, only! See what I mean by cheap & flimsy? LOL.............

It will require major stiffening before it can be used.