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#1 SudorracMechEng May 07, 2012 05:41 AM

wiggle drive propulsion
 
Hi, i was looking at using the wiggle drive for a surfboard application - whereby two fins could be oscillating and a system will be in place to lock the fins in initial position once desired speed is achieved.

I am a final year mechanical engineering student, I am wondering which principle is used for the following: (ill try my best to explain)

The two fins will be Vertically mounted, they will flap from left to right and the pitch will be around +- 15 degrees.

It will be running off the same idea as this video

Swashdrive™ Fin propulsion 2 (1 min 21 sec)

#2 der kapitan May 07, 2012 12:29 PM

Interesting, but is there any mechanical advantage to this over a propeller?

#3 green-boat May 07, 2012 12:43 PM

Impressive to see that kind of speed out of a couple of fins. As for seeing it before ..... nope.

#4 420TEE May 07, 2012 02:01 PM

Interesting idea but a lot more moving parts to break than a shaft and prop.

#5 Umi_Ryuzuki May 07, 2012 02:37 PM

High speed sculling... exceptional engineering.

:cool:

I can see where that might be applied to an RC or robotic squid. :)

#6 boater_dave May 07, 2012 02:43 PM

Hobie uses that system in the their pedal powered kayak. The flippers only move in one axis and rely on thier flexing to provide the thrust. I would guess they move through 80 degrees of motion. The video looks to have a very complex motion through multiple axis. One advantage of the Hobie system is that you can short stroke the fins at the end of their travel to traverse very shallow water.
Interesting, either way.

Dave

http://www.hobiecat.com/kayaking/

#7 fooman2008 May 07, 2012 07:45 PM

not to be negative but she does look like she could use a little trim, maybe lower the bow a little as she comes out of the hole. Neat idea though.....
Foo

#8 Rhizome May 07, 2012 08:30 PM

I want one! where do I order..? looks like that boat has a hydrofoil on it too - might explain the erratic behavior.

On watching the first video it doesn't appear to be a hydrofoil - just a small fin.

#9 capntroy May 08, 2012 01:50 AM

Quote:

Originally Posted by boater_dave (Post 21545381)
Hobie uses that system in the their pedal powered kayak. The flippers only move in one axis and rely on thier flexing to provide the thrust. I would guess they move through 80 degrees of motion. The video looks to have a very complex motion through multiple axis. One advantage of the Hobie system is that you can short stroke the fins at the end of their travel to traverse very shallow water.
Interesting, either way.

Dave

http://www.hobiecat.com/kayaking/

The Hobie Mirage drive is pretty ingenious and it takes a fairly small physical effort to get the boat cooking along, if you were hand paddling at the same speed, you'd be working your butt off...and the fins actually move through 180 degrees of motion.

I had to assemble and water test 20 of them for a project and they all worked great, you can adjust the height of the pedals and the length of throw, so a really short person or a really tall person can adjust the boat to suit their size.

#10 Lil aus Aug 17, 2012 05:30 AM

Heah Guys

thats my mad lil invention, it uses modified cranking swashplates to create the fin movement ,in fact the 2 fins cancel each others lateral forces, providing exceptional thrust. Its a similar motion to the hobie mirage but a totally different mechanism.
the question on bow up getting on the plane is because throttle feathering in required, to mush power at this point and she blows bubbles, it has a nature of more in fin surface speed more grip !
Happy to field any questions
regards
Craig
Swashdrive

#11 fredspak Aug 17, 2012 09:22 AM

Can it go in reverse, also???

#12 boaterguy Aug 17, 2012 01:47 PM

I wouldn't think so.
lil aus, any chance we can see what's inside? I'm really interested to see how you did it, wouldn't you need multiple swashes to move through all the axis?

#13 Lil aus Aug 17, 2012 05:08 PM

1 Attachment(s)
Heah

Too set the record strait, this unit is a swashdrive, not a wiggle drive, that is another bloke Kjell doing a similar thing !

Yeah, sure does work in reverse, but i don't have a phase relay on the 3 phase motor, it would mean swapping 2 wires as you prob know, but yes the mechanism work backwards as well as forwards .

At first loading the video i was fairly reserved at showing any detail of working parts, but already some Orni guys soon figured it out, its now well & truly public and any chance of a Patent are gone, worthless anyway, doesn't stop china !

At first bearings may seem an issue, but if you after run with oil, or use a ceramic its not a problem.
Efficency of it is outstanding and a very weird beast, its almost backward to the way it drives, I never really thought it would work as well as it did, so i'm as surprised as you guys. I don't really want to give a % in Efficency, cause i don't want to fight with sceptical ones, fact is it works !.
This should show whats goin on, the technology is a Lill' complex at first, but there is enough info there someone could build it !
regards
Craig


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