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Author Topic: my tripple screw landing craft...  (Read 4161 times)

rathikrishna

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my tripple screw landing craft...
« on: September 28, 2010, 03:04:05 PM »

Thank you all...from your opinions i have compleated a landing craft, with three screws...its working nicely....thank you again....all....
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sailorboy61

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Re: my tripple screw landing craft...
« Reply #1 on: September 28, 2010, 05:14:30 PM »

You are a very prolific builder.... a great example to those of use with money/tools/parts etc what can be acheived just for the love of building something from what seems like mostly nothing. Congratulations.
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mattycoops43

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Re: my tripple screw landing craft...
« Reply #2 on: September 28, 2010, 05:19:37 PM »

Did you make those propellers? very impressive if you did! Things like that make me think twice.  %%
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Shipmate60

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Re: my tripple screw landing craft...
« Reply #3 on: September 28, 2010, 05:42:51 PM »

rathikrishna,
Is there any way in the design stage that you could try and make the propshaft angle smaller.
This will Flatten out the driveline and give more efficient drive through the water.

But a superb model as usual.

Bob
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rathikrishna

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Re: my tripple screw landing craft...
« Reply #4 on: September 30, 2010, 06:42:46 AM »

Good morning and thank you all once again...sure because , after joining in to MBMH, i could learn ample of things from many authorised persons...once a three screw craft was my nightmare because of ignorance in maritime technology. my research subject is aeronautics. now i am too proud and happy, because i have some good friends and guidance from MBMH.and in to subject... all propellers are hand made..i purchased 1 square feet of zink sheet from a bus body building material supplier shop, and drawn three circles by a compass.then divided it in to 120 degree each, with a protactor,from an school geometry box, then cuts in to shape with meat slicing scissors.two of them are angled with a rounded nose plier towrds out, and centre one spins with the adjoining one. i do not have any outlet for motors here, so i searched in a scrapyard and found some toy motors, and rewinded its armature for a 7.5 volt. i replaced its back plastic cover with brass bushes, taken from old walkman capstan assy. all three motors drawn only 800 Ma, so with a 3.2 ah battery, in to 7.5 volt, nimh, telephone battery, it runs more than an hour...without heating up motors...i used a toy rc for it, from an rc helicopter, and works nice...speed controller made from a toy gear box,one spins a volume controller , one controls the base bias of power transistor.i will post all my prooven circuits here...motor speed controller, rudder, thrust pump controller..all...
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sailorboy61

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Re: my tripple screw landing craft...
« Reply #5 on: September 30, 2010, 07:24:11 AM »

 :-))   :-))   :-))


Amazing!
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tony52

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Re: my tripple screw landing craft...
« Reply #6 on: September 30, 2010, 02:09:42 PM »

Rathikrishna
When you sail this new craft. will you be posting a youtube film as you did with the puffer?

Tony.

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andrewh

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Re: my tripple screw landing craft...
« Reply #7 on: September 30, 2010, 05:05:19 PM »

rathikrishna,

Magnificent - thanks for showing us. 

You are clearly very resourceful person - there don't seem to be many people able and happy to rewind a motor :}

I love your transistor speed controller as well  - please tell us about it!  Are you using a 2N3055?

More, please
andrew
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mogogear

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Re: my tripple screw landing craft...
« Reply #8 on: October 01, 2010, 12:29:56 AM »

Very nice indeed!!

 IS there a rudder I am not finding? :embarrassed:
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bassplayer1

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Re: my tripple screw landing craft...
« Reply #9 on: October 03, 2010, 12:47:34 AM »

Thank you for sharing!!!
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mersey dave

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Re: my tripple screw landing craft...
« Reply #10 on: October 03, 2010, 11:11:47 AM »

Very nice indeed!!

 IS there a rudder I am not finding? :embarrassed:

I was thinking the same.

regards dave.
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rathikrishna

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Re: my tripple screw landing craft...
« Reply #11 on: October 06, 2010, 07:19:45 AM »

Good morning all my respected friends...sorry for the delay in reply as i was in duty and was bussy..sorry...i will share all my knowledge here indeed ...this craft uses no rudder...instead i accomplish turning it in two way...first one ..i made a cetrifugal thrust pump at its bow, a pump lies horizontally to the hull..without a pressure cavity..so it will pumps in either direction when direction of the motor reverses...so it can turn instantly within its own length from a stand still..secondly three of the final motors are controlled independently in same instance.so if i want to turn left,(PORT) the shaft of the port side will be in reverse, while the starboard side is in forward direction, while the centre one pumps towrds foreward...so it will boost the turning effort in a violent manner..all these simultaneous controlls are full filled by a toy R/C with some RELAYs and transistors.i will post all of my controlling circuits here one by one..but with a request..dont make fun upon me...because all thins are developed myself, with limited resourses within my place. i designed and crafted all equipments because of my helplesness...here i cant attain any costly and quality equipments here...and yes i am very unwilling for that, because i can make 2 meter long craft for around 5 US Dollars..so with my money i can make ample of models...so i will post all of my ideas here...sure...
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mattycoops43

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Re: my tripple screw landing craft...
« Reply #12 on: October 06, 2010, 09:58:02 AM »

I don't think any of would make fun. we're all impressed with what you do!

Can I suggest it might work well to have one of the outer motors stop, while the other side keeps going, to make a more gentle turn> or do you already do that? it's just that you only mention putting a motor into reverse!

Matt
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rathikrishna

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Re: my tripple screw landing craft...
« Reply #13 on: October 07, 2010, 09:05:09 AM »

Sir..it is fully indepentadly controlled..while you choose a turn to port, the prop at the port side start to spin in reverse, means, it pumps water to stearn..while the centre props turns same .means to forward..while the starboard prop pumps to stearn..all togather with the centrifugal pump, situated at front side of the craft...so it will turn within its own length.i will post a video soon, as i am alone now, and i need one to hold camera.sure..
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Shipmate60

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Re: my tripple screw landing craft...
« Reply #14 on: October 07, 2010, 05:30:31 PM »

rathikrishna,
No-one will make fun at all.
Like me we are amazed at what you do with your resources.

Bob
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rathikrishna

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Re: my tripple screw landing craft...
« Reply #15 on: October 08, 2010, 09:05:10 AM »

Thanks once again..i will post all specs here related all my crafts..soon a video also...
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