I am working up to make an RC hovercraft which will be using a BLDC motor for lift system,
a brushed DC motor for propulsion system
a servo for rudder assembly.
I do not have a standard Tx Rx system(futaba or alike), so i have decided to develop a Tx Rx system which will be used to switch ON and OFF the lifting motor(BLDC motor) and wil be able to run the propulsion motor at low,med,high speeds and in reverse direction.
Also ,it will be able to control the rudder servo.
now where i am facing problem right now is the issue with BLDC motor. I want to know that can it be triggered using a 555 timer IC connected to the ESC which is further connected to the battery and BDLC motor.
If this is possible then i would like to know HOW?
A 555 ic alone can do this job ?or a microcontroller is a must?
i have attached circuits and draft build
PS.-bdlc-brushless dc motor
      esc-electronic speed controller

Check this circuit:
www.rcindia.org/self-designed-diy-and-college-projects/cheap-servo-esc-driver/

It uses a 556 timer IC. You can easily drive an ESC with it.
BTW, which tx-rx ckt. are you planning to build?

Thanks for the response sir.
Well we are making a Tx Rx set analogous to fan regulator.
We are referring to the circuits attached above.
As i am new to RC stuff, i want ur guidance to proceed in correct direction.
Can the circuits i had attached be used in conjunction with the circuit u referred me to (using 556) TO CONTROL BLDC MOTOR WITH ESC?
i am relying solely on ur response so please answer carefully.(i need to develop this as my final year project and submit it within next 5-7 days )
if possible,gimme a call at 08882324282

Saurabh, it is  very easy to make an hover craft.. use a plenum chamber under the craft.. use small lift fan compared to big dia, to eliminate torque reaction.. a plenum chamber will increase efficinecy to 80 % and takes less power to lift up.. you can simply use motors from CD drives instead of a brushed motor.. this helps to reduce weight to a great extent with immense power delivery.. use small fans for propultions with a kort nozzle, and add fins, on it, go with thrust vector instead of conventional rudder assy.. this gives you a very keen steering controls with accuracy.. you can also try with contra rotating props in small dia, for lift fans, gives you a very high quality controls instead of wavy own its own like responses.. making an ESC and drives are easy, but today you can buy ESCs for 450 or less Rs/- so, the time and effort is saved a lots.. for skirts, in dry situation you can use moderm umbrella cloths with silver lininng inside or can use poly flex sheets that used in bag making.. can buy in various grades.. a plenum chamber is a must, to save energy and for correct nature.. with three CD drive motors you can use two 850 mA/H batteries in to 7.2 volts, will give you a run time about 20 minutes..remember, an improper designed hover craft wastes a greater energy in vain.. and you must use a flexible skirt on it, so, it works in any surface with ease.. can also try with small BLDCs, or can also try with brushed motors.. but motors from CD drives will be amazing because of its high power delivery to weight and size..cool screammmmmmmmmm.. have some nice crafts..

making a radio set is quite easy..but i think buying a second hand radio is far better than making one.. you can rearrange the potentiometrs of the TX for a thrust control mixing, and can also use a simple Gyro, to control the lift and thrust motor variations.. this gives you a pin point accurate controls, instead of running all the way.. a suction duct will also increases the efficiency of lift fans.. you can make a big good craft from straw board, of 3mm thick ( Coro sheet).. it will be more easy to make pleanum chamber with sections.. lifts like a lift..with very less power..  a small dia 3 bladed prop will be more better.. a duct fan from a SMPS can also use for lift fans.. works great with CD drive motors..

Tx- rx analogous to fan regulator?
Why don't you use a toy-car radio instead?
The best suggestion I can give you now is get a cheap airplane radio so you can easily control ESC and rudder servo. Use the brushed motor for lift and use a switch to turn it on/ off. And use the BLDC for thrust.

Swapnil sir,i saw ur 556 ic based circuit and i must say that u did a great job.
Now my concern is :
1. can an ESC and a SERVO both be controlled by the single circuit simultaneously?
2. is it necessary that the ESC should be of BLDC motor only and cannot be an ESC of BRUSHED motor?
3. what are the pros and cons of contra rotating props and should i consider them to be used in our project?
4. i have 3 batteries (cellphone) of 950,1300 ,1350 mAh respectively.can i use them in series to power the entire apparatus on craft?
We r running out of time,it would be great if u can respond quickly.:-)

i donot have a toy car now.
How can i use that toy car radio btw?
I mean if i buy a new toy car,what will i be able to do with the Tx Rx set of it?
(considering that the RC toy car can move in forward and backward direction plus LEFT and RIGHT motion)
also,i wanna clear myself on it: how many channels are said to be there in this RC car? 4 or 2? i oftn get confused with this.:-)

1) An ESC and servo can be given a common signal but then you won't be able to control them independently.

2) BLDC ESCs are completely different from brushed ESCs. They have FET pairs that are switched on at a phase difference. Brushed ESCs simply won't work.
(And you must have noticed that BLDCs have 3 wires and brushed ESCs have 2, so...)

3) I've used them in HoverBot v2. They work good.

4) The mAh rating just shows stored charge density and not the max current batteries can supply. Cellphone batteries don't have high 'C' rating as high current isn't required. As such, they can't be used for powering your motors. (Search what LiPo 'C' rating means and you'll understand)

Toy car radios can be used if you can interface their receivers with a micro-controller. Otherwise it'll be difficult.

thank u swapnil sir.
I hav one more question to ask. can i use a brushed motor and a brushed motor ESC with the 556 based circuit u recommended?
Also, can u provide me the other side(bottom) of the 556 based circuit?please

Yes, you can certainly use the servo driver circuit for a brushed ESC that works on servo signals.
The bottom of the circuit is just tracks, no components are there. The circuit diagram (first pic) is very simple. If you have any questions regarding that, please ask.

ok...
Q1.what are j1 n j2 used for?,if they are not sorted to j1 n j2 respectively??

They are simple jumpers. Pin 2 goes to pin 6 and 5 goes to 8.

can this circuit be used to control one ESC and one SERVO simultaneously?
If yes then how?
Also ,i would like to know what wud happen if we use same kind of capacitors used in the circuit(paper capacitor for example).
And one more thing ,the circuit diagram has got 2 POTS but u have used only one pot in the designed pcb.WHY? moreover, one resistor is also missing(i m not sure which one)...
I wil apreciate if u can give us the back side of the pcb so that we can get a better idea of components placement.

No, you'll need two seperate circuits for servo and ESC.
The 2nd pot isn't soldered. It goes into the male header pins at the right side.
I dismantled that PCB long ago. If you follow the circuit as it is, there should be no problems.

Thank u sir.
But it seems dat u missed my query regarding CAPACITORS...:-)

Thats because I didn't clearly understand your query.

HELLO VC sir n SWAPNIL sir!
I have 7 more days to complete the hovercraft.
As we are lacking time and money and EXPERTISE i thought to work up on the design considerations.
I thought to make up a hole at 30-40 degrees from horizontal and extend it through a duct like structure with a conical ending(nozzle like structure)..
I think that upon switching the lift motor,it will generate too much of thrust(as you suggested me VC sir,in case i go with BLDC 2822 motor)....
So in essence ,we will use some part of the lifting pressure/thrust to provide the craft linear motion.
We may use a LID (optional) for hovering at a place.
wat do u suggest VC sir?I need ur EXPERT advice once again.:-)
Sketches linked- https://picasaweb.google.com/111375374001884649365/HovercraftNewDesign

ok....well my question is that IS IT NECESSARY TO USE DIFFERENT TYPES(paper cap,electrolytic cap and ceramic cap) OF CAPACITORS IN THE CIRCUIT?
what wud happen if we use all the capacitors of same kind(say paper capacitor for example).

It's not necessary. Back then, I just used whichever gave best results.

PLEASE COMMENT ON THIS DESIGN.:-)
https://picasaweb.google.com/111375374001884649365/HovercraftNewDesign

I checked out your designs and here's what I think.

1) The thrust nozzle will act as a pressure outlet and will shift CG resulting in lower efficiency and imbalance.

2) It won't give good enough thrust to overcome inertia.

There will be a slight tendency to rotate because of lift motor torque at full throttle. Better take that into consideration.

A non-circular duct (as in 1st pic) is inefficient (gives much less lift) due to leakage at corners. Consider changing that as well.

What if i make  piping on both the left n right boundaries of the hull.
Cylindrical structure ,without nozzle, one on the extreme left and other on the extreme right ?
U think it will work?

Why don't you give it a try? If it doesn't work you can try other methods.

swapnil sir.,i have designed ur 556 based circuit but its not able to generate required delay.
I tested it with a servo....can u please assist me here?