RC India

hi everyone,after trying my hands on rc planes,im trying to make a rc hovercraft,these are components i have

two 64mm edf's
one 2s and one 3s battery of 1000 mah
two 30amp esc
9g servos

i will start the work from tomorrow,i had some doubts regarding the electronics and the skirt design,hope people in this forum(especially VC sir) would help to design a better hovercraft

i have some things in my mind,i want to design the hovercraft with some properties
they are:

1.drift should be probably minimum.
2.hovercraft outlook should be good.
3.probably with more duration for the hovercraft (i don't know exactly how to improve this)

there are some more questions:

1what is the best material to design the skirt?
2.how should the skirt is attached to the base?(gluing,taping at the edges?)
3.regarding the electronics i have two edf's so how can i connect both of the edf to the receiver?
4.how to reduce the drift effect and control it?
5.which material can be used for the entire deign and for the base?(coro,thermocol,insulation foam)


this is the circuit diagram..i want to know whether it is correct or not
if i connect two esc's as shown in the pic will the receiver be damaged..?
iam using +12 lipo batteries. plz do check the pic and suggest me if thr r any corrections to be made for the circuit..

good luck for your rc hovercraft  :thumbsup:

here in some engineering college there were some competitions regarding hovercraft
will be posting link of the  videos soon
u will get ideas from it   

pls check this video

u will get some help from it
http://www.youtube.com/watch?v=RmYB7nIY1ss (http://www.youtube.com/watch?v=RmYB7nIY1ss)

My partner Great Guns and I will be happy to render any assistance. All the best!

Btw Shubhambilawar, RC Hovercraft Modellers from India have posted much better videos of Scale RC Hovercrafts (much bigger at 1.2 metre / 4 feet and above in size) on Youtube. Search and you shall find them.

I am talking about 3 scale RC Hovercrafts (1:20 Scale approx) that have been adopted by the Indian Army for a Training School to train their pilots of the future.

Hi Harsha!
I found this great site sometime ago.

http://www.raymondclan.com/hover/hover.html

You'll find good hovercraft theory, description of materials required and step-by-step build instructions.

And then here's the best one if you want to build a scale model:
http://www.model-hovercraft.com/plans.html

But above all, there's VC sir! The amount of knowledge he posseses can get you through your build process easily.  :bow:  :salute:

Check out the first site in the above post, you'll have most of your doubts cleared (regarding build material and construction).

Here's a few suggestions from me:

* To minimize drift you could use a microcontroller with suitable sensors or simply make suitable control surfaces.
* As with aircraft, the duration will depend on AUW and the electronics you use.
* The best material for skirt, as VC sir will tell you, is ripstop.
* Regarding your diagram, you can connect both ESC' to a single channel of receiver (say, throttle channel) using a Y-harness so that they pump in the same amount of air. Better use one for lift and the other for thrust.
* Also, while using a single battery make sure it can satisfy the current requirements of both the ESCs and other electronics.

VC sir, please correct me if I'm wrong in any of the above.

first of all thanq very much for the responses......... :hatsoff:

ya swapnil,im reading the links that you have sent me,thanq.one more thing is that,yes i can connect the two motors using a single esc,but i want to control the motors separately,i want to get the lift continuously and i want the thrust to be controlled separately,so i want to connect the circuit as shown in the pic,but my only doubt is that if i supply 12v input for both of the esc's and connecting them to two different channels this may damage the rx?????

You don't have to connect the two ESCs to two different channels. You can connect both the ESCs to a single channel using a Y-harness.
Also, don't try to use a single ESC for both the motors.

To control thrust seperately, you'll need a radio with a 2-position/ 3-position switch. Which radio do you have?

fsth9x

Two control two motors separately, the best is to connect them to two different channels.  Remove the red wire from one of the ESCs, so that only one of them will power the receiver.  Depending on what you want to do with those motors, you may need to use programmable mixes in radio programming.

ya i will use set throttle range option in my esc,but anwar bhai im still a bit confused can you show it in the diagram??(red wire means positive and black means negative,so you are suggesting to connect only one esc to the battery and the other without connecting to the battery?)

Err... let me try to explain in a bit more detail.

1.  Both both ESCs, 3 thick wires go to the motor.

2.  For both ESCs, 2 thick wires will go to battery or batteries.  Whether to use one battery to power both ESCs, or use separate batteries is up to you (and your design/weight) requirements.  Depending on your decision, you may have more soldering/connector setup to do.

3.  Now we come to the wires that go from the ESCs to the receiver.  I assume you are using an ESC with a built in BEC that supplies around 5V to the receiver.  Each of these wires are actually 3 wires in one, with a connector that can be plugged directly into one of the receiver channels.  From ONE of these two "3 wire" connections that go from the ESC to the receiver, remove the middle wire. This ensures that only one of the ESCs will power the RX.  It is best that you do not cut/remove the ESC receiver wire itself, instead use a spare servo extension, and do the surgery on that.

ok vc sir
i din't knew about this
i will check that soon :)

First thing first, if I were to do it my way, I would want to have a mental picture of what my Hovercraft is going to look like once it is ready. How big will I want it to be? Everything else (build material, power etc.) will depend on that final product.

Harsha, what do you REALLY want to build? I would begin with the end in mind. :thumbsup:

anwar bhai i got it,i think one of our forum member subbu had done this method already as shown here

http://www.rcindia.org/self-designed-diy-and-college-projects/the-white-pearl-twin-ducted-fan-hovercraft/

i think you suggested me the method as shown in the last pic of the first msg.
another thing is can we use two different voltage batteries to power the thrust and lift edf's???is it possible to do like this??(sorry if i ask a very stupid question  ;D )

ya vc sir,actually im trying to build the design like this one

http://www.rcgroups.com/forums/showthread.php?t=899477

but i dint see any skirt in this hovercraft vc sir,how is it possible?

Attempting to answer the following questions, based on my limited experience. These answers are by no means sacrosanct. After all, scratchbuilding is all about experimenting.

1.what is the best material to design the skirt?
2.how should the skirt is attached to the base?(gluing,taping at the edges?)
3.regarding the electronics i have two edf's so how can i connect both of the edf to the receiver?
4.how to reduce the drift effect and control it?
5.which material can be used for the entire deign and for the base?(coro,thermocol,insulation foam)

1. Ripstop / Car weather cover. Umbrella material is too thick.
2. We used the best quality 3M Double sided tape.
3. Answered by Anwar Sahab.
4. Answered by Swapnil.
5. We used Coro deck surfaces and superstructures epoxied onto a styrofoam base. Edges of the craft were reinforced with wooden frames.

Hope this helps.

If you check my first Hovercraft, it featured a rigid skirt made with nitrile piping available at Air Conditioning equipment stores. It essentially traps the air under the craft and forms a cushion for the vehicle to ride on.

Check this out:

http://www.rcindia.org/self-designed-diy-and-college-projects/scratch-built-hovercraft/75/

finally started the hovercraft building,actually its an easy way to construct a hovercraft which can be completed in single day.but as i said before i have some requirements like it should be good looking and efficient.here you can read about my build process.

step 1:first took some high density thermocol and some coro sheets.
step 2:cut down the entire thermocol piece into required model dimension(i followed roughly no exact dimensions.)
step 3:now cut down two pieces of coro into the same shape.
step 4:now as we have 3 pieces,first coro piece is for base,middle piece is thermocol,top piece is again coro.
step 5:the top piece,near to its center the slot for edf is cut down.
step 6:the same shape is cut down in both the pieces.
step 7:now the top piece is made such that the outer most body(skeletal design for the hovercraft) is made by joining one by one coro pieces.
step 8:the bottom piece and middle piece are joined using fevicol.

this is the work done by me till now,i will upload some pics now,but they might not be that clear as im taking the pics with my mobile,so tomorrow i will update again with my work....... ;D

some more pics

I like this design. Good job!

thanq vc sir,sir i have a doubt,if we add skirt only to the borders how will the hovercraft properties modified and if we add a full skirt which covers the whole bottom area how its going to behave???? which is the better option??

I'm sorry I don't understand. Can you explain this, perhaps, with a diagram? From what I can make out, you plan to cover the entire underside with the skirt and then tape the edges to the sides of the craft. Where will the air escape from to provide the cushion?

finally the project is completed,tomorrow i will upload the videos and pictures. ;D

Congrats! Waiting for the pics and videos.

http://www.facebook.com/video/video.php?v=142609519159373&notif_t=video_processed

http://www.facebook.com/video/video.php?v=142649152488743
360 degrees test

http://www.facebook.com/video/video.php?v=142660285820963
the sound of edf is heavy as i took the video inside my home....... ;D....forgive me for that sound guys

Nice built.... {:)}

Superb! I wish I could build something like this.

All your hard work and labour have paid off. She seems capable of high speed and is very maneuverable. You must post a video of this baby running around in a bigger arena.

Congratulations!!!! :salute:

thanq very much vc sir,sure i will try to maiden it in a bigger arena and post a video

how have you programmed the radio for the 2 edfs. does the one providing vertical thrust run at a constant speed ie on- off with the retracts switch or is it proportional  like the flaps?
regards
avijit

Awesome!  {:)}  :thumbsup:

Could you please tell us about the power setup in detail.
Also, where did you get the EDF's from and how much did they cost you?
I'm itching to build one for a school project too after watching your beautiful build!

@avijit:i used the throttle option that is increasing and decreasing the lift and the other channel to control the thrust.i followed the suggestion of anwar sir,you can see it in the first page.

@swapnil:i got it from hobbypartz.com they cost around 26$ excluding shipping.they are really awesome swapnil,brand is aerodrive.btwn all the best for your project :)