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new to airboats got a question about motor and prop

Old 10-02-2014, 06:34 PM
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shanjay
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Default new to airboats got a question about motor and prop

i am rather new to this and not sure what to do but i am starting a airboat project and im gonna go electric i already have a redline 13.5 tekin brushless what options do i have for prop and hubs that will work on a 5 lbs fiberglass hull?

thanks for any help
Old 10-02-2014, 06:36 PM
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shanjay
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it may weigh a little less than 5 lbs havent weighed it yet
Old 10-03-2014, 02:08 PM
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Jeremy_H
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I know nothing of electrics shanjay, hopefully someone will come along that can advise, it's pretty quiet here.

In the mean time is the boat build under way? It's always interesting to see pics of folks projects.
Old 10-03-2014, 02:40 PM
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shanjay
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yes its under way jeremy its being built from scratch fiberglass it will look like i small scale cottonmouth deck over i have no pics but i will get some from some research i have done the motor i have will work well but i have to up the size of the prop and battery but not sure what size
right now i have been expeirementing with a 10x5 3 blade prop but it is to small so i gotta find out what size i need my motor flattings the prop if you know what i mean
i have built and put together real air boats but rc is a new rodeo for me
Old 10-03-2014, 02:52 PM
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shanjay
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also if anyone interested i have a really good friend that makes all types of boat hulls and sells them for just a few examples check him out on youtube at ackler boats
Old 10-04-2014, 10:51 PM
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shanjay
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well worst waste of time in my life to sign up for a membership on this site thanks for all the help guys
Old 10-05-2014, 03:50 AM
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Don't give up, Try the airplane 1/2a section. Don
Old 10-05-2014, 02:29 PM
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71dartswinger
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Try posting in electric plane section
most of us use nitro/weedeater motors
Old 10-05-2014, 02:45 PM
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If you want good electric advice, seek Crispyspa on RCU, RCAirboats.net, or YouTube. He is very knowledgeable in the ways of electron powered airboats. I don't think he frequents RCU much these days.


Also, you need to have patience. Expecting answers in 2 days is a bit much. I built a boat 4 years ago and I still don't have all the answers to making it work right. You have to give it time.

Last edited by 1QwkSport2.5r; 10-05-2014 at 02:52 PM.
Old 10-06-2014, 10:44 PM
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crispyspa
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Sorry you had to wait, I don't come in here very often anymore..

Here is the prop adapter you will need.
http://www3.towerhobbies.com/cgi-bin...?&I=LXMSG3&P=7

Do you have an ESC? I'm not finding any Wattage or voltage info on that motor. I'm going to assume it will take up to 6 cell lipo. Prop size depends on the size of the boat and that directly effects what ESC you want to get. Being a 3400kv motor with a prop on it, 3 cell maybe be the max you'll want to go. With a 10x8" prop and 3 cell, I can see that motor pulling around 100A.

Give more specifics on the boat and I could figure a little closer. I would recommend getting an outrunner anyway. That car motor isn't ideal for an airboat and motors can be had at Hobby King for cheap.
Old 10-07-2014, 06:01 AM
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1QwkSport2.5r
 
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His royal crispness hath spoken! Haha, kidding aside. Thanks for sharing that info. Hopefully the OP hasn't bailed out on us.
Old 10-07-2014, 01:37 PM
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shanjay
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ok thanks crispyspa for the info i do have a wsc b ut i been working on the boat at a friends house so im not sure what kind it is all my stuff is there im going there this weekend and ill post info then and possibly pictures if i can figure out how to post them lol thanks again for the info i was inpatient but i been waiting awhile to put it together and even longer to find any info so i apologize but thanks
shanjay

i have gotten some more info but not much but from i understand to run that motor ill need a 7.4 volt 5000mah 45-60c lipo............ does this sound right and in this hobby is bigger better if i have a smaller boat and i run alot of power what would be the pros and cons

Last edited by shanjay; 10-07-2014 at 01:50 PM.
Old 10-07-2014, 08:42 PM
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Get some details on the motor too. Near as I can figure, the 13.5t Tekin is the Gen2 1-3 cell motor so a two cell will be fine, I think it is the RPM series as opposed to the High Torque series.

One problem I've run into with an electric airboat, most (cheaper) aircraft ESCs are not waterproof and the marine ESCs require a water pick up.
Old 01-06-2015, 12:36 PM
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I plan on converting a customers boat to a brushless electric. The Traxxas VXL 3500 1/10th scale motor and speed control for cars is made to be waterproof. I will be mounting both on deck behind the prop so they should run plenty cool.
Old 01-08-2015, 04:02 AM
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What kind/size of boat, what prop and how many cells will you use? That is a pretty high Kv motor for a direct drive propeller, it is designed for a gear drive. To keep it from burning up you may need to use a relatively small prop which may not drive a larger boat very fast. Good cooling may not make up for excessive amp draw, although running in freezing weather will help...


.
Old 01-08-2015, 01:16 PM
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It's all wood and about 2 1/2 feet long by 1 1/2 feet wide and looks just like the one in 1QwkSport2.5r's profile pic. I think the prop on the nitro engine was a 10x7 maybe? I was thinking about using a 6-8 cell NIMH for safety reasons. I might also be looking to source a gear transmission to use with this combination. Any suggestions?

Last edited by jimjeep; 01-08-2015 at 01:19 PM.
Old 01-08-2015, 01:32 PM
  #17  
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Cool

That is 'way too much prop for that motor, you will burn up the ESC and then the motor. The prop size is a bit big for the boat although it may work with the right motor. I suggest an outrunner motor, they have several advantages over an inrunner like the Traxxas:

1) They have more torque and can spin a larger prop, essential for decent airboat performance.
2) They are very efficient at relatively low rpm.
3) They are easier to dry out when they get wet (flip, spray, etc.) so they last longer.


I run a semi-scale catamaran-type airboat of similar size with a Scorpion SII 3026-1190 Kv outrunner on 4S and get speeds in the mid-30s on a 9x6 prop. Your flatty will not go quite as fast. Similar motors are available from the infamous HobbyKing for less $$$ but less quality too. Depends on what the customer wants to pay. Scorpions are near top of the line with great efficiency.

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Old 01-08-2015, 02:20 PM
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jimjeep
 
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Thank you very much for your input. I will have to look into that as a better option for this conversion if I end up doing it. I will have to find a suitable speed controller for it as I would like something that will be able to use NiMH packs as well as LiPos. The original electrics and nitro motor are very old. I would estimate about 35 years old. Nice boat you have there! Is that motor mounted on a PVC pipe?

Last edited by jimjeep; 01-08-2015 at 02:24 PM.
Old 01-08-2015, 05:31 PM
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Got RPM
 
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Yes it is. Here is the thread which explains what I did.


http://www.rcuniverse.com/forum/rc-s...-r-c-boat.html


Most modern brushless ESCs work fine with NiMH packs but often there is no low voltage cutoff.


.

Last edited by Got RPM; 01-08-2015 at 05:34 PM.
Old 01-09-2015, 08:01 AM
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1QwkSport2.5r
 
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I saw a reference to my flatty airboat (Kamikaze) mentioned. JimJeep's boat is 30x18, but the weight is unknown. For a reference, my boat is 32x18 and weighs about 7lbs RTR and I prop it with a 13x6-13x8 on water and 12x10, 13x6, 7, 8, and 13x10 on grass. The 13x7 is good for 40mph+ On water. Depending on the weight of the JimJeep's boat, an 11" diameter prop will be a minimum on grass or water. I get about 15-20mph on water with an 11x6-7 prop and 10cc engine.
Old 01-10-2015, 07:40 AM
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Thanks for the input1 Qwk, data is always good to have. The OP will need more motor and power to achieve comparable speeds - depending on what he wants for speed. And 4S will not be enough either, a minimum of 6S.

.
Old 01-10-2015, 09:13 AM
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1QwkSport2.5r
 
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Originally Posted by Got RPM View Post
Thanks for the input1 Qwk, data is always good to have. The OP will need more motor and power to achieve comparable speeds - depending on what he wants for speed. And 4S will not be enough either, a minimum of 6S.

.
I'm not very fluent in the ways of electrons, but yes it will take some power and a better motor to make that boat move at anything faster than a crawl on grass. A 5-6lb boat on grass likely won't even move with a 10x7 or comparable size prop.

Also, the OP isn't the latest poster we are talking with. The thread got hijacked. Not a big deal to me, the OP hasn't been back since he got mad he didn't get an immediate response to his questions.

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