Good after noon all respected modelers.. one of the ever discussed topic about a model may be the submarine and hover crafts.. and we can see ample of discussions on scratch built hover crafts like essays.. ample of ideas and opinions..  if we looks around us we will simply find the needed materials around us.. and by understanding the principles of a hover craft we will realize its nothing.. but i never tell you all easy as workmanship and way of thinking plays an important role in model making.. say frankly i am not much interested in hover crafts and helicopters.. but as a modeler it is not good to stay away from any model..and this simple hover craft is designed and developed for my Science Park, as part of the tech display.. about how an hover craft works.. so, this one is not the first one, for them, and is not my first one.. but as a commissioned job, it is not possible to add here all but i got a permission to publish about this little craft.. the first one is 2.5 feet long and it was completed with heavy fans.. but the second one is 2 feet long, and powered by simple and light stuffs.. as you can see it is so humble and simple..

about the first big one.. adding the base here so many beginners can under stand how easy it all...this one is big and powered with powerful motors..

so, from here we are entering to the simplest craft.. the entire craft is made of 5 mm foam board.. the conda ducts were placed with 3 mm foam boards.. one of the main mechanical perfection lays in it's thrust propulsion fans..so at first i tried with small fan achieved from a robotic kit.. and here i am showing you that it how easy to integrate a brushed and brushless motor on a same receiver..
the duct ring is made of paper..

and see here the simple attachment.. the twin rudder panel is controlled by a micro servo, and integration of links were realized by two spare servo horns..

the body.. the instruction from the Principal Sir, of Science Park, to me is that, " it must be basic and crudely built", as they want to show how things works.. so here a straight forward method of construction is utilized.. the lift chamber is basic as the students can see all inside..
the lift fan is comparatively huge to it's hull size.. this gives us a great power to weight ratio without disturbing and straining the motor much..
one of the great discussions took upon the skirt materials.. we need nothing as expensive.. see here..

Excited..

the simple installations of propulsion motor assy..
and after some test drives i found the thrust generated by the little fan is too low.. motor was under strain.. so i reworked on the propulsion system with a 4 inch aero prop.. a total rework..

the previous thrust assy in detail.. can see how easy to make a thrust variator..

Dharmik.. hold it..

now the reworked prop system in detail.. all simple..
the panel is controlled by a simple micro servo..

 the craft is so stable..

because of the gyroscopic stability, you can operate her from a bed or from a desk.. this synchronization allows us a great braking, and turning from axis in 360 degree..  and action time..

she is so fast.. so its too hard to operate with one hand.. but still adding a simple video, that i shot with some hard work.. and for her no matter as sand, gravel, water, tarmac..

how much money that we can spend on an hover craft..?  here i spend nothing than for the material as foam board.. and about Rs 20/- for skirt.. including stitching.. see the simple action here.. will add more long time various terrain videos once i get some of my friends with me...

all respected Friends of modeling.. here we saw the integration of brushed and brushless motors on a same receiver..and a same battery.. along with a simple gyro.. and once we understands the basics we can navigate through any modeling.. from here you can see the making an hover craft is simplified.. a simple lift fan.. a simple propulsion fan.. the craft is ready..

 

here i used a very high RPM motor for lift fan.. and a simple reworked brushed motor for propulsion fan.. the total time of running with a 2200 mA/H battery is about 30 minutes, in optimum speed and 20 minutes at good speed levels.. so, from here i realizes that i need one hover craft in my personal collection.. so i am in my work shop to make a good hover craft with high end finishing.. but still that one will not be a copy of any known craft..  

thank you Sumit.. and still working on it for even more performance..

hello sir,
             im also building a hovercraft.sir actually i have three motors with me first one is the one which is blue in colour ,the same which i sent it to u ,second one is emax 2822 and finally i have turnigy 850kv motor.i cant decide which motor to use for lift and propulsion.http://www.aeroworks.co.in/motor_1312.html
i have the motor mentioned in the above link also,please guide me.sir i plannig yo use 4mm coro to bulit the craft.which is better either coro or foam board??

and all respected modelers..here i am thanking a million times to Flysky and Hobby King, for bringing us the great radio sets are value for money and those helping me a lots in my modeling projects.. how nice and perfect it all.. and from here it is clear that we do not need a complex computer controlled radio set to operate a complicated craft.. mostly i use a basic 4 channel radio with servo reverse switch in panel.. great options for customization.. nice units.. 

Jeevan, please do not spend your time while looking in to the specs of motors.. instead, please come in to reality that a big prop with a low RPM motor, means more counter torque... so your craft will start to behave erratically when the lift fan is activated.. instead go for a high RPM motor with a small dia prop will eliminate the torque effects a lots.. a 4 inch simple two or three blade prop along with a 2600 RPM type ECM will help you lots.. use a conda vanes in opposite to your motor thrust direction.. or simply can make a hole at the opposite side of your craft to the thrust.. this hole can be controlled by a micro servo as open and closed... so this will stay as stable as a rock.. nothing is tough.. have a nice machine..

thank you sir!!!!!
really u r a real craftsman!!!!

Great build and great work sir.

Indeed a nice build roopesh Sir...
Your work has been an inspiration for us...

In the quest of making a hovercraft I have come across many other fantastic builds too which also conquered with flying colours on RCI...

I want to ask you sir, are you trying to say that those are not practical and their work is not useful...?

Thankyou..

thank you all..
Adi.. here my work is so humble.. and i was taking lots of inspiration from the all above works.. and to me one of the greatest guru of hover craft to us all the respected senior VC Sir.. when i looks in to his postings and dedication, i always inspired a lots.. nothing can match the dedication that all seniors putting in the modeling.. and my works are no match for the comparison with those works..   and a million thanks for the guidance of the words that i accidently typed there..

I too was a little surprised after reading that comment. I am no Hovercraft Guru. There are kids who are less than half my age who have successfully crafted RC Hovercraft and operated them at competitions much before I started building my first craft. It is they who have inspired me. If they didn't prove that it could be done, I wouldn't have dared do it. To them -  

Dear Roopesh Excellent build there 

However three things I need clarifications or could not agree with.

1.  Could you please elaborate on how you have employed a Gyro for Stabilization in such a simple Hovercraft mechanism where you have used only two motors one for lift and other for propulsion. I don't see How one could achieve stabilization with just these two motors and Gyro.

2.  The way you have placed the electronics on the lower board, it is very much susceptible to get wet when run on water and further in case of mid water drain out of battery your electronics is going to fry.

3.   Lastly I wonder how you have achieved a 30 Minutes endurance with a High KV 2822 Brushless and a brushed motor running simultaneously on a Single 2200AH Lipo, while it is possible to achieve barely 10 - 15 Min run time with a single Brushless 2822/6 2200 KV on Single 2200 AH Lipo run on 70% throttle.

Sundaram Sir, i am eliminating the gyro as it is too hard to control the main lift fan, as it not allowing the lift fan to rev up.. so, rewiring a little with direct connections.. and yes i have to replace the all electronics to top side and also have to add a buoyancy platform just under the below deck.. as you mentioned in case of any failure.. the 30 minutes is at land with light throttle.. the brushed motor drain a little current.. but after a long run, i am not dare enough to drive her in water.. and this one is made for the only demo spec Sir.. i am working on my own one.. little bigger..
VC Sir.. you are a true inspiration to us all.. i always wonder while reading the postings about your big hover craft.. its amazing..

Dear Roopesh I am not able to fathom how you were proposing to use a gyro for stabilization, while a gyro provides only stabilization to one or few axis of rotation and especially when you have used only two motors one for lift and other for propulsion more so when gyro provides rotational stability, when what you need is positional stability when it comes to hover craft unlike an aircraft.

A typical 2822/6 2200 KV runs for just about 10 mins on WOT with a 2200mah.  If you are able to run that for about 30 Mins along with a brushed system in parallel then you are able to achieve a lift in just about 30% Throttle and then your lift fan is too over powered than what is required.

Sundaram Sir,  it is possible to use a gyro stabilization in one axis as this was using in my speed boats to avoid roll over by cutting the main motor speed when the rudder is applied in either direction.. the response speed can calibrate when we fixes the gyro with ESC.. i have two modes to achieve this.. the first one i call as the direct mode and i do not know is there any technical name.. is, the main, or intended motor is controlled in a way as to increase or to decrease the running speed according to our need by reversing the servo switch.. means, for an example here, one of the disturbing nature of a hover craft is rotating from its own axis when main lift fan switches on.. so, we can ascertain the needed RPM to get sufficient lift.. so, at that point we can add the guiding slots to the opposite side of the hull, or can add thrust vectoring vanes according to our plan and needs.. so at that moment the craft will become stable to a great extent..still it will sway side to side uncontrollably.. so, to add a little more stabilization i used the variation of the speed of the main motor once, as it starts to rotate the input from the TX for rudder instantly feds a signal to ESC to rev to low or rev to high to stabilize the craft.. this direction can be controlled by the reversing switches over TX.. means towards high speed or to lower speeds.. and it will be back in normal RPM when the stick input stops.. here i am adding a video, as the first one showing my TX direct mode.. in this mode you can see the speed of the main motor is altered by the rudder inputs.. here no external vibrations or disorientation are needed.. but to me in to this craft restricts the free throttle responses..

the second mode of configuration is the gyro mode itself.. that you can see the speed of main motor is controlled by gyro itself.. here in both videos the actions are violent as to get a high outputs from machine.. but when in normal cruise these happen in a needed way.. you can see the variation in main motor speed as i jerks the gyro.. the fast erratic movements of the craft triggers the gyro, and feeds the ESC a correction signal.. this almost resembles a gyro control of a single rotor helicopter.. you can also see the instant response of rudder panel all the while.. and Sundaram Sir.. here i am thanking you a million times as because of your comment i was rechecking about possible configurations of a gyro in any craft.. and got two more configurations as by using the unused channels are 5 and 6.. result is exciting.. but here with this craft it is not possible to carry on the research.. because by tomorrow noon i have to hand over to the students.. before that i have to replace all electronics to top and have to fix some thermocol panels at bottom panel.. for safety..
Sir, here my expiriment showing that it is possible to add a gyro in to one and alone motor.. with rudder inputs and by gyro.. for you i removed the propulsion motor connections and it's ESC to isolate the machine from drive motor.. and was using many of my crafts.. i have only a little gyro from a scraped helicopter, and may be we can find lots of functions from an expensive one.. as i found in the hands of Vinodettan, from Futaba..

About run time.. yes you are sure.. the lift fan configuration is too efficient that it needs only about the throttle level about 15 to 20 % as you can see in my first and second video, and with a 50% throttle this one can lift a wet brick and hover.. and i never gave up in front of commercially available stuffs.. that you never forget that i always RCs my boat from 5 O clock to 5.45, eve with a single battery of 1800 mA/H in my boats.. with a 1000 RPM 160 watt motor.. and reworking gives us the options that we want.. as i fixed two expensive motors in my 5 feet long yacht.. the result was disastrous.. but when i reworked in my manner it became a big success.. and because of your comment i rechecked the timing, this time not on sand, but from the foreground of my grand home.. lots of gravel and grass.. still giving me up about 20 minutes as i pumped the propulsion motor to great accelerations..

anyhow, your comment gave me some more opportunity to learn more Sir.. here is the second experimenting video.. shows gyro actions the only one motor this signal can be feeded to propulsive motor as well.. and with a 50% throttle she can hold a full wet brick.. because of the efficient plenum chamber.. simple humble and success.. and thank you for the advice to replace the electronics to top.. 

        I had no doubts about this earlier. After reading at length, Roopesh I can only say  you have absolutely no understanding whatsoever about the functioning of a Gyro and the purpose for which it is used for, further how and where it is supposed to be used for.

I feel sometime you belittle your own strength as a scratch builder and of every other scratch builder by your unsubstantiated unnecessary inflated claims.

Scratch building is all about simplicity, creativity, ingenuity, an art of utilizing least resources, making do with whatever little available and creating a masterpiece. I am sure everyone will agree you are an maestro in that field.      

    I don't understand why then you have to add complexity to it by adding technical mambo jumbo, further by making unnecessary claims and showing yourself so poorly time and again. This forum is subscribed by people who are much more accomplished. I consider myself as a novice when compared to them. I don't know how you are finding yourself comfortable in dishing out such fairy tales to them and ridiculing their acumen. This you have been pointed out many times before too that such claims will mislead many youngsters.

My only advice to you would be to please refrain. Project your strength and do not expose your weakness.

With this I am unsubscribing to this thread. Thank you Roopesh.

Holy Mother of God! This coming from an Officer and a PERFECT Gentleman like Sandy. I hope the person concerned takes heed. After all, this is not the first time that such things have been pointed out to him. Mr. Sushil Anand had something similar to say about some electronic circuits earlier.

My two penny bits - if a 1 metre scale Hovercraft weighing around 5 kgs can remain stable without a Gyro and work on 4 simple brushed motors, why needlessly and deliberately scare would be modellers away with all this technical mumbo jumbo?

One of our responsibilities (IMHO) is to make this hobby accessible to all and sundry. If we wish to make complicated models, we are free to do so, however, let us underplay the technicalities so as not to make them feel that scratchbuilding is a daunting task.

+1 Sandy.

Btw, the integration of brushed and brushless motors on the same Rx was achieved long ago (19 months ago). Please don't claim this as your brain child.

i claimed here nothing VC Sir.. but was telling the synchronization of both motors is easy.. nothing is my brain child.. and i am not the first or alone one to use a gyro to stabilize the hover craft.. here i am adding two links that shows many modelers are using the gyros from helicopters and others to stabilize hover crafts..

http://www.rc-hovercrafts.com/forum/viewtopic.php?f=11&t=123

http://www.rcgroups.com/forums/showthread.php?t=1172173

so nothing is my brain child..