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Title: my first hovercraft Post by: alok roxx on July 28, 2011, 11:21:08 AM decided to build my first hovercraft.........
been searching for ideas and plans....... i think i have got the necessary material. will start work next wednesday. will be experimenting with wall and inflatable skirts........ what i want to know is... will a hovercraft with wall skirt hover over water?? all the hovercrafts videos i found were using inflatable.... i need guidance on building the 'craft...... :help: Title: Re: my first hovercraft Post by: aditya on July 28, 2011, 12:10:10 PM contact v.c. sir...
have a vast experience in building rc hovercraft.... Title: Re: my first hovercraft Post by: sunk? on July 28, 2011, 02:28:19 PM hi mate.
Yes.......... check out this site. http://www.jameshovercraft.co.uk/hover/html/srn1/srn1.htm (http://www.jameshovercraft.co.uk/hover/html/srn1/srn1.htm) an early commercial hovercraft. a wall skirt, as apposed to a flexy skirt, does cause 'height' limitations of where the hovercraft will go........ie if floating on a 2mm cushion, then 2mm is the height restriction of obstacles. regards don Title: Re: my first hovercraft Post by: alok roxx on August 24, 2011, 04:55:05 AM thanks a lot sir!!!!
Title: Re: my first hovercraft Post by: alok roxx on September 14, 2011, 06:44:05 PM umm...... ;D ok, i was a little busy with exams going on.........
hav finally found parts for the 'craft...... :) but i have found that it rotaates like crazy when the lift motor is on............. i havent fitted the thrust fan or control surfaces, but wanted to see of i had enough power to get it to lift 1" off the ground........ i am using a mini rc heli rotor for the lift fan and a pc processor fan for thrust........... right now, my hovercraft is nothing more than a thermocol box open at one end and with a round hole at the other end...... this being my first hovercraft, i am concentrating on seeing whether it will fly rather than the looks........... need lots of guidance on doing this correctly... :help: :help: Title: Re: my first hovercraft Post by: roopeshkrishna on September 14, 2011, 07:30:03 PM Alok, making an hover craft is easy, with a twin baffle idea, and with a flexible skirt. you need powerful motor, or motors, may by nature, or reworked. a main rotor system from a tiny helicopter seldom lifts, but a 1000 rpm /Volts BLDC with 9 inch prop will do the job nicely. you can use a second motor for propulsion, or can control with same lift motor by adding thrust ports. you can take the craft in water, with a flexible skirt, wall too, but a flexible skirt gives us a good maneuverability.to avoid the thrust reaction, you can make a stater just under the main fan, with thick paper. you can control two motors with same receiver, with same battery pack, with some simple modifications.waiting to see your craft running..have a nice build. :thumbsup:
Title: Re: my first hovercraft Post by: roopeshkrishna on September 14, 2011, 07:33:54 PM we must take extreme precautions while making hovercrafts, than airplane, as a severe jerk in motor mounting can pluck off the motor prop assy, instantly throwing anywhere in our vicinity. so try to fix the motor mounting with a balsa, or thin plywood sheet, within a ring made out of seasoned paper, with guards. try to wear the eye protector while handling the BLDCs with power. :hatsoff:
Title: Re: my first hovercraft Post by: rsQire on September 14, 2011, 08:16:14 PM Hello alok
you have to cancel the unbalanced moments on the craft to stop it from rotating.this can be done in many ways 1)mount the lift motor perpendicular to the hull(like the thrust fan) and then make a duct to divert the air underneath the craft 2)use two motors whose axis are in the same line and have rotating and counter rotating props on them so that the moment of one prop is balanced by the other or use two motors at same distance from c.g. with rotating and counter rotating props 3)make some vent holes in the skirt which provide rotation in direction opposite to that caused by the lift fan. Title: Re: my first hovercraft Post by: asinghatiya on September 15, 2011, 10:21:18 AM How about using two duct fans.. :thumbsup:...I guess they are much safe & swift than propellar and moter, installed at 90degree to eachother. One to facing the bottm to lift the base and other horozontal to push the lifted base.
Just see this... http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=16606 Title: Re: my first hovercraft Post by: alok roxx on September 15, 2011, 07:43:07 PM heyy thanks for all the replies!! i tried with the mini rc fan, able to get 2" lift.
still unable to get a ducted fan for thrust, not allowed to shop online........:) found that cutting a hole to let the air escapefrom behind gives a small thrust............. since im trying to build a slow craft for experimental purposes this seems to be a very practical solution........... it seems the craft can work quite well at upto 50% air loss through vents.......... took the advice from the reply post and found that putting holes to provide counterthrust in order to reduce spinning effect and found it to be VERY effective....... thanks..........:) Title: Re: my first hovercraft Post by: alok roxx on September 16, 2011, 07:09:33 AM tried shifting the weight around on the craft...... found that concentrating weight on corner reduces spin.
closed up all the vent holes..... increased weight on front of the 'craft........ goes forward due to more air escaping from back....but this seems to reduce front hoverhight to barely 1cm....... still havent got a thrust motor......so im gonna stick with this till i get one....... video of the hover test @ http://www.youtube.com/watch?v=CbrPdRcfdwo planning to make this one wire controlled........ so battery not mounted...... Title: Re: my first hovercraft Post by: alok roxx on September 16, 2011, 07:11:52 AM sorry abt the video..... took it by myself...... didnot hav time to edit.....;)
Title: Re: my first hovercraft Post by: sunk? on January 08, 2012, 06:02:58 PM hi alok roxx
you are trying to get 'too much lift'..... this a hover craft 'not' a plane. :) you only need 2mm of lift to as a average so with the power of the motor and prop you are using you could divert a lot of the down thrust back wards to give forward motion. and put a rudder in the backward air stream to steer it with. the problem you have with spinning is probably because the motor is too powerfull for the weight of the craft and lifting it tooo high which could actualty turn it over. but good thinking so far...if you cut vents too big they can be made smaller or sealed with sticky tape untill you have found the right size vents. regards don. |