its my HOVY BLACK CAT.. the rc hover craft...

Started by roopeshkrishna, September 20, 2012, 12:31:21 PM

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sundaram

Dear Roopesh Excellent build there  :thumbsup:

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.

roopeshkrishna

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.. :salute: :hatsoff:
Phoenix.........

sundaram

#27
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.

roopeshkrishna

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..


Phoenix.........

roopeshkrishna

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..  :salute:

Phoenix.........

sundaram

#30
 :o  :o  :o  :o 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.  {:)}  {:)}  {:)}

:banghead:  :banghead: 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.

VC

#31
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. :hatsoff:

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.
Growing old is mandatory, growing up is optional!

roopeshkrishna

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..
Phoenix.........