View Full Version : Motors Needed!!!

05-18-2009, 08:37 PM
Hi all,
I have to take part in a event known as CYCLOTRON held at Modern School,Barakhamba Road,New delhi. Actually I study in this school. All of you are invited to take part but only children under 16 years can take part.In one of the events i have to make a motor boat.There will be a race between boats.It has to be wired.

So,i have never worked on a boat so can any body tell about the motors to be used,,No.of motors to be used,Propellers to be used and where to get all these material(basically propellor).I'm not so good in mechanics.I'll do the programming part & circuit designing as i'm good at it.

As of now i have planned to make boat using PVC sheet 3.5 mm as base.This is because it light & wont let water cross,I'll make a covering of boat using this same sheet it will protect circuit & motors.I'm thinking of making a simple base with a streamlined shape. IF YOU KNOW ANY OTHER BASE BETTER THAN THIS PLEASE LET ME KNOW.

I'm planning to use two motors both around 400rpm.I think the appropriate weight will be from 70gms - 170gms.I think these will work fine.I think we can get them at LRM or meena bazaar.If you think that i won't get them there then tell me the place & cost.MY BUDGET IS Rs1500.

I'm totaly dumb at propellors please help me.If possible let me know about a good & easy tutorial.I searched for them online,everything went over my head.The circuit & program is ready no need to help in that.

I think the total weight of boat will cross 600gms easily.I dont know it will float or sink as i havn't seen the arena as yet.Please let me know how to keep it floating.I think shape will play a major role.So, it'll be tough using PVC as base.Its tough to give them shape.I think i can use some sort of balloons or some flexible ball type of thing in which i can fill air so that it helps in floating of boat.

If any of you want meet me & help me out Please contact me at 27568686.Actually i really need your help.If you wish and are free please call me.I think it'll be experiencefull journey for me.

NOTE:I haven't bought any material as yet for this boat.I have just planned this in my mind.I'll start making models with your advice.I dont want to spend money just like this.

05-18-2009, 11:31 PM
Hi Kido(hope u dont mind!!!!)),
Good to see your enthu..........but ur post really made me giggle and reminded me of my school days...:-).........FYI I made a balsa wood boat when I was in 8th grade...no complex electronics or RF control .....they costed more than my whole years pocket money that time..hahaha.......go to CP there is a hobby shop by the name Indian Hobby center opposite a cinema hall(I can't remember the name i think it was Plaza) ..buy a balsa wood sheet and a descent propeller or a balsa wood motor boat atleast they used to have one 12-15yrs back...........
it would be good if you understand how fans and propellers work.....use google....you live in the internet age.............


05-18-2009, 11:37 PM
Hi all,
Thanks man!Ya the name is correct.I've been there before.CP is not really close to my place so i wont take a risk.If you can tell me the cost of motor & any contact no. of the shop.I dont want that to happen,I enter the shop ask for motor they don't have it or its costly(over my budget).Its no point i go this far and get disappointed.Please give me their contact no or website if possible.

Thanks Again
Regards Akshay,

05-19-2009, 08:38 AM
You can try 12V high power DC motors. Ask for 'printer' motors , the shopkeepers will generally have them. Those motors are somewhat powerful and will work well. Dont go for the normal 12V motors , they are useless , they have no proper torque in water. The printer motors cost around 80rs. They are generally sold 2nd hand- but that doesnt really matter.
BTW , i feel that 1 motor should be enough. 2 Motors would be overkill. It will be harder to implement speed control by PWM for both at a time.

As for the propeller , you can use mini aircraft propellers which are available in some aeroclubs. I had made a similar project 2 yrs back for my schools science fair and i had used a printer motor and the propeller from a model aeroplane kit.
It seemed to work pretty well.

Now , water propellers are available here in Bangalore from OM electronics at around 30rs or so. I haven't tested it , but it should work , i guess.
Here is a pic of the propeller , it should be definitely available in delhi.

I had also made a air propelled boat sometime back. I had used a powerful 24V exhaust fan and had mounted it along with pivoting for direction control and two mini 12V lead acid batteries for power. The air from the exhaust fan used to propel the boat. It worked pretty well. The lead acid batteries were extremely heavy though so it was a slow- around 1feet/second. You could probably get a good speed since your boat race is wired and there is no need to keep the batteries on the boat.
Here is the pic of the exhaust fan that i used :

As for the base , why dont you simply buy a large plastic dabba and modify it? That is what i generally do. And it works all the time. It is leak proof also. You will have a headache waterproofing the whole thing if you try to make your own base with balsa wood or something else.

05-19-2009, 10:45 AM
Hi all,
Thanks for your motor suggestion.I really liked your suggestion.I'm pretty aware of these motors & have used them in past.So,no problem using them.

I think the propellors used in computers for cooling purpose will do the work or the other option is to order them from:


Please have a look at the link & guide me in buying propellors.

Regards Akshay,

05-19-2009, 10:58 AM
hmm...none of the propellers on that website seem to be perfectly compatible with a motors shaft. You will have to make a mechanism to fix the propeller to the motor yourself i guess. That will make it very hard. You will have to properly align the axis of the propeller to the motor shaft. Even a little bit of misalignment will cause the motor to start shaking. I have also faced a lot of problems in this regard.

I agree with with your idea of using computer cooling fan. The center of most bigger cooling fans already has a hole which fits the motor shaft perfectly. You could probably use that i think.

05-19-2009, 12:26 PM
Hi all,
Check this out:


I think i'll make this but with a different shape.The speed is alright,propellor can be easily made & mounting motor will also be easy.I think i'll make this.

05-19-2009, 12:38 PM
Lots of advice above , here is my bit -

I would have tried to make my boat as light as possible , and used a high RPM motor for the propeller with Li-ion/Ni-Cd batteries ( Very small but good Current and voltage ). IT has to run for 5 minutes to win the race.

Now do you need a turning mechanism or it just goes straight ?
1. No turning what ur doing is fine
2. Turning required - Servo based / Dual motors with PWM ( easier ) .

Keep weight to the minimum, and output all the power into propellers. Try to get propellers from toy boats which are sold in toy shops else you have to make one.

05-19-2009, 01:17 PM
Hi all,
Thanks for some advice.Finally i've decided to make a boat like one above.Its easy to build.I'll make the propellor myself.The motor i have are 350rpm.i am using two motors of same kind.The sterring is no problem.

Regards Akshay,

05-22-2009, 10:42 AM
Hi all,
I think i will use 2 of these motors. These motors have good torque,less weight(40gms),High rpm & less price.


But i'm a bit confused about the rpm.I think 250 is more than enough or i should go for 375.Please give your advice so that i can order them as soon as possible.

Regards Akshay,