You can get them at rcsuperstore.com for $45 each. Wire in series for 6s operation. I’m running 1400kv in my UL1 with an X443 on it. It will take more prop, but you’ll pick up more prop walking too. The hull will only take so much speed...
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Prop walking?Comment
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Prop walk is the same as sponson dancing, happens when there’s too much prop torque.Comment
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Same thing as chining? I'm having a lot of problems with that now on 4s running either the UL-19 stock prop or the GrimRacer 40x57 prop. The boat is fine up to about 44mph but as soon as I hit 45 it starts bouncing all over.Comment
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I saw in another thread someone built a pointed air dam under the boat that directed air to the sides. He then cut a hole in the webbing on the side of the boat for the air to escape. It looks like it didn't need to be glassed over where he cut out so I'm thinking on cutting the webbing off entirely. Most hydros I've seen since don't have that webbing to trap air under the boat.Comment
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Chining is different. That’s the boat dragging on the non-trip surfaces. You see that more in V hulls and Cats, but a hydro can dig a chine on the corner, normally results in a the boat flipping sideways. Prop walk induces a side to side oscillation, dancing from one sponson to the next.Originally posted by InspGadgt View PostComment
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Interesting...that's what I've been told chining is...bouncing from one sponson to the other. GrimRacer calls it "Chine Walk" in this thread: https://forums.offshoreelectrics.com...how-to-stop-itOriginally posted by CraigP View Post
At any rate that's what i'm having...the side to side oscillation really bad. I've just tried sharpening and balancing one of my props and I was hoping to test it out this weekend to see what a difference it made. But I ended up having to work.Comment
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It’s just a word, no big deal... I come from full size boat racing and that term was usually applied to flat bottom hulls.
A dull prop can certainly cause this. If the prop is sharp, the diameter may be too big for the hull. I get my batts out across the sponsons to put weight out as far as I can. It’s called (in my world anyway) centrifugal damping. Think of ice skaters, when they come in for their final spin, they start with their arms (or weight) out. The spin is slow... Then they slowly bring their arms in and the rotational speed increases to a max speed when their arms are tucked and hands on their chest. That’s how they designed the ISS to rotate the center section at the right speed to simulate gravity.
If you put all your weight on the boat’s centerline, then you have virtually no damping at all. My batteries length is 90 degrees to the centerline.Comment
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Your right it's no big deal and I mean no offense. I'm just trying to keep things straight. As a new person to boats I hear a lot of different terms for the same thing so it can get confusing so I'm just trying to make sure I'm clear.
Yeah I was postulating in another thread that maybe these hydros should be designed to run the batteries in the sponsons for that exact reason. That and the lower CG should help to reduce blow overs. Basically the wider out you put the mass the more it will resist rotating. Just like the figure skating example you mentioned...not only do they bring their arms in to increase their spin speed, they also extend them to slow down and stop their spin as well. While it will take more force to get the mass moving further out...the downside is once that mass is moving it has more momentum and is harder to stop rotating. So once the walking hits a certain point there will be no stopping it from going over. (One of my never finished majors in college was physics)Comment
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Anyway back to the idea of cutting off all the webbing. Here is the post I mentioned where someone made a V type airdam and cut holes in the webbing to allow the air to escape. https://forums.offshoreelectrics.com...008#post720008
It looks to me like the hull isn't compromised by cutting the hole in the webbing...which leads me to think I could cut off all the webbing and still not compromise the hull. I'd like your input on if you think this would compromise the hull. I'm thinking it will go a long way to calming down the boat. For my own piece of mind I'd like someone else's input before I start cutting on fiberglass that could potentially compromise my boat.Comment
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So I did it...I cut off the webbing to try and help calm the boat down. Hopefully I didn't just make it worse. Anyway I have to wait for parts to come in to try it out because I split the collet nut trying to tighten it the other day.
Webbing removed.jpg
Webbing removed 2.jpgComment
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Didn't get to test this weekend due to the hurricane that almost hit us. Hopefully I can this coming weekend.Comment
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Didn't help
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It needs the proper weight balancing and an aero wing up front. I velcro’d in a 90g weight on the left side, just in front of the battery. That helped it a bunch to about 50mph. I then built and added an aero wing to the front (some call it a canard wing, but it’s not). This is a reverse-lift wing, designed and placed on the boat to come into Max downforce at about 4-5 degrees of bow lift. I took it off of the UL-1 and put it on my dual motor DF34, which needed it more.
Wings are complicated, need to be calculated out and built to a template. Or just “wing it” and carve one out of a good piece of hickory and throw it on there! Many say good things about aero dams in the air tunnel. They can solve one specific problem at a given boat attitude, but tend to make problems outside of those operating areas. But I’m not going to get into it on the website. Just look at the problem thru your own eyes and apply what you think will fix it. Best way to learn, instead of listening to a bunch of asshats like me!Comment
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I used a carbon fiber helicopter blade cut down as a front wing. I made sure the curvature was facing downward so that it would add downforce instead of lift. It looked cool but didn't really help. I plan to try it again but add some spoiler to the back for more downforce.
90g! I tried 200g but mostly centerline. I only put 2 ounces on the left side. Sounds like I might need more.
Even asshats can have a good idea or 2 :)Comment
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