Posted May 31, 201113 yr Shall we? Description: http://sariel.pl/2011/05/quadramaran/ Photos: http://www.brickshelf.com/cgi-bin/gallery.cgi?f=474198 Hulls: http://www.bricklink.com/catalogItem.asp?P=50821c01 Propellers: http://www.bricklink.com/catalogItem.asp?P=2952
May 31, 201113 yr I like the simplicity of the design, and the great manueverability of the quandramaran. I was wondering if that kid with the stick was going to wack the boat!
May 31, 201113 yr Author I like the simplicity of the design, and the great manueverability of the quandramaran. I was wondering if that kid with the stick was going to wack the boat! I gave him my meanest look, just as a precaution.
May 31, 201113 yr Whats wrong with the kids nowadays? My RC boat had to evade a stone attack once. Anyway, simple and working design.
June 1, 201113 yr Looks pretty daring to put a power functions driven thing on water like this. About the video; loved the "captain's view" - very calm actually (at least, with sound disabled). Great video overall, but the model in itself is actually not even very interesting. ;)
June 1, 201113 yr Author Great video overall, but the model in itself is actually not even very interesting. ;) I know, I know, and I didn't even catch any pretty lady in the background this time :(
June 3, 201113 yr Very nice idea! I love it! Since i've been having ideas of my own, i would like to ask you some questions about your model. Have you considered the maximum distance, over which you are going to have infrared control over your model. As far as i know, its about 10 meteres or so for the PF remote. I'm asking this, since there's a possibility of your model remaining in the water beyond the reach of the remote, which would be truly inconvenient What was the speed of your motorboat? Did you consider using this motor: boat motor ( plus another PF motor to control the rudder) Keep up the great work!
June 3, 201113 yr Author Have you considered the maximum distance, over which you are going to have infrared control over your model. As far as i know, its about 10 meteres or so for the PF remote. It's no more than 3 meters outdoors in the open. Which is why I've used the PF speed dial remote - it makes the motors keep going even when the IR link is lost. This way, I was able to make the boat go in large circles - I made it start to turn, it went far away from the shore and kept turning even though the IR link was lost, until it came back close enough to be within the range of the remote. What was the speed of your motorboat? I would have to think of a reliable way of measuring it first. Did you consider using this motor: boat motor( plus another PF motor to control the rudder) I see no pros, only cons of using this motor. Namely: 1. it's much less effective that the propulsion system I've used, 2. the rudder is tiny and would require a large external control mechanism, 3. I had some trouble with algae getting tangled in the propellers and while it was not much of a problem with the propellers I've used, it could damage this motor. Edited June 3, 201113 yr by Sariel
June 3, 201113 yr So it seems i haven't thought about my idea in sufficient depth! Thank you for the reply! Off-topic: do you think a LEGO Hovercraft sounds feasable?
June 3, 201113 yr Author Off-topic: do you think a LEGO Hovercraft sounds feasable? This was done by another LUGPol member years ago:
June 3, 201113 yr Oh ... ( speachless) End of off-topic, thanks for satisfying my curiosity :) How did you end up choosing the particular propellers for your model ? Here's an afterthought about your model: Did you consider using these propellers (the new ones from Atlantis): boat propeller My guess is, they would scoop more water? I have never tested their performance compared to the ones you used though. Though they're with a circular hole for technic pins, I guess they wont spin freely if connected to blue half-pin: pin with friction
June 3, 201113 yr Author How did you end up choosing the particular propellers for your model ? They turned out to be most efficient in my tests. When choosing a propeller, you have to look for balance between the small ones, which are inefficient, and large ones which require large torque. I believe these particular propellers are very efficient because they're relatively large (9 studs diameter) and have blades of little surface (no large torque required). And while they come with two blades each, you can easily combine them into 4-bladed units. My research on Lego propellers has been independently confirmed by another LUGPol member, who has been running plenty of efficiency tests. Did you consider using these propellers (the new ones from Atlantis): boat propeller They appear to be completely flat on the image. I mean, the shape of blades doesn't allow them to push water forward or backward. I'm afraid this is one of the Lego propellers that are made just to look nice. But this is still not as bad as certain Exo-Force turbine: http://www.bricklink.com/catalogItem.asp?P=53983pb01 It's big turbine with plenty of blades, and it looks very promising until you notice that the inner and outer ring have blades set at opposite angles to each other. It could be quite an interesting piece, but someone at Lego decided otherwise :)
June 3, 201113 yr Hi again! Hope you don't mind all the questions from me today :) I agree the blades you've used are pretty good. I remember i've used them for air-propelled vehicles, but never tried them to scoop water. The water-turbine-propellers are not flat though. I can take some in-depth photos and share them here. I suspect their drag will be much higher, thus making them less efficient than the ones you've used. I'll gladly test them on a m-motor without any reduction ( 1:1, as i see you've done in your model) If you want, i can share the results here. One more propeller i thought might have some good results: 3-blade prop. with 24-tooth gear I think it would be worthed to try it out in water. I want to thank you for all the information you shared! You give me lots of inspiration! Keep it up!
June 3, 201113 yr Author Hope you don't mind all the questions from me today :) Not at all. One more propeller i thought might have some good results: 3-blade prop. with 24-tooth gear That looks very interesting, I think I'll get it and test it, thank you.
June 4, 201113 yr Nice cans there Luc2000. (sorry 'bout that) nice use of the cans for flotation, but from the way its leaning back there it looks far less stable that the quadramaran, putting your PF at much greater risk, and are the props pushing or pulling?
June 5, 201113 yr The props are pushing, the side with 2 canisters is the front. Actually, the rear canister wasn't even necessary, that's why I removed it in the third version. Links to unedited videos of version 2 and 3. 3 works a lot better. Complete set is in the previous post.
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.