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The drive looks fixed with a solid shaft. If that's the case, then there is no adjustment.
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Sometimes if the bottom is "hooked"---meaning the surface of the bottom near the transom is not perfectly flat, any bumps or bulges, you get this kind of porpoising, there is really nothing you can do except you will need to fill and sand the ride pad. A lot of work for a RTR---IMO. But, the guy is pushing the speed and that exaggerates the porpoising character. I had some of that with one of my boats, she was hopping crazy, after I flattened the bottom it ran beautifully. Trim tabs can't completely eliminate this problem.
DSCN4932_5181.jpgDSCN4969_5211.jpg
The difference before and after was night and day.
IMO, sit tight and wait for your hull to arrive and put whatever you think will work for you and go from there. It may turn out ok and will be a good first boat for you.
cheers!Too many boats, not enough time...
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Thanks for sharing these tips. I really like the boat in your video and how it runs.
Hull should be here Monday or Tuesday. I'm a bit impatient, almost thinking about ordering the Leopard 2860 3400Kv motor and the appropriate ESC now. Obviously the mount can hold it (judging by the pics of that guy on ebay). Seems to me the boat has enough power with similar motor, it's problems are elsewhere, not power. Also, if I go with the smaller motor, I'll have more options for battery since space is limited, might be more difficult to feed the bigger motor (as you mentioned earlier).Comment
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These are the things I'm set for, the only thing holding me back from submitting my order is not knowing what motor coupler I'll need (don't know the size of the drive), so I'll wait to receive the hull and measure:
Leo 2860-3400kv + 40mm long cooling jacket: http://www.offshoreelectrics.com/pro...?prod=leo-2860
Hobby Wing Seaking 120A: http://www.offshoreelectrics.com/pro...er-seaking-120
Traxxas 2075 servo + futaba servo arms: http://www.offshoreelectrics.com/pro...p?prod=dh-2075
Adjustable Trim Tabs: http://www.offshoreelectrics.com/pro...od=ose-tab1015
I already have a good transmitter and receiver.
Other than the motor coupler, am I forgetting something else I might need to complete this boat? I'll try it with a 3S battery, which I'll buy locally, as well as any tubing I'll need.
...still having second thoughts on the motor, don't know if I'm making a mistake, maybe I should get a 36mm motor... damn first boat, never thought I would be so indecisive. Maybe when I get the hull, if the spacing is 25mm, I should then get the 36mm, and let this be the deciding factor...Comment
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The elongated holes should accommodate either the 36xx or 28xx motors, I think.
The only thing you need to keep in mind is that for a 3400kv motor, you are pretty much "stuck" with 3s battery, not that you will have much room to spare to run 2x2s anyway, IMO.
Your shopping list looks good, I will put the trim tab on later, make sure the tabs are spaced correctly, meaning there will be enough space for you to put them on between the rudder and the stuffing tube, I don't know how wide the transom is, you also have the flood chamber on the port side. Don't mean to say this in a snobbish way: but a well tune/running boat should not depend on trim tabs.
Also double check inside the transom, make sure there is a so-called "transom doubler" in there, it strengthens the transom for any hardware that will be attached there. I think you are ok, but just to make sure.
When the trim tabs are to be mounted, the tabs do not go flush with the bottom, it should be 1mm above the bottom. On bigger boats it is raised up even more, like 2 mm. Look at the second picture I posted. :)Too many boats, not enough time...Comment
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Good point about spacing the tabs evenly on the transom---just another reason to wait for the hull to arrive and make sure there is enough space for the tabs I buy.
By the way, am I right in my thinking: then the choice of 28xx vs 36xx has to do with what battery I want to run (in my case I might be limited by space, but I'm asking in general). Basically, if I wanted to (and could) use a bigger (in voltage) battery, the choice would be 36xx with a lower Kv that can support the higher voltage, and if I could use a smaller battery, then the 28xx with higher Kv? What other differences and considerations are there when choosing the motor size?
Remember, I'm just starting with this hobby, so I'm just trying to understand how it all works, sorry if my question turns out to be really dumb
By the way, the specs for the Leopard 2860 / 3400 Kv call for 17V lipo, so I guess i do have the option of running 3S and also 4S with is, is that right?Comment
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Sorry, at work, you are correct in many ways, I just think that since very few of us know this hull, a 3400kv on 4s is spinning a very fast prop, theoretically its ok, but real world might be different. Usually a 2200kv is good with 4s. For sport boating that is.
Sent from my Droid using Tapatalk 2Too many boats, not enough time...Comment
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If I got this correctly, approximately this is how it goes:
4s lipo: 2200 kv x 14.8 v = 32,560 rpm
3s lipo: 3400 kv x 11.1 v = 37,740 rpm
For the Leopard 2860, they do have lower KV versions too. Next lower is 2730 kv x 11.1 = 30,303. I wonder if that won't be better than the 3400...hmm..
Of course, then there is the choice of prop... 35mm x 1.4 pitch, or different...2 blades vs 3 blades....Last edited by corsara; 04-27-2014, 02:19 PM.Comment
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My opinion is like this, for 3s, you can use the higher kv, but you would not have the option to run 4s. So if there might be room to run 4s, I will go with lower kv, please note that 2730kv on 4s =40404rpm, that is too high for this hull, because there is a threshold with these sport hulls, beyond a certain speed I am afraid you will have a very temperamental boat. Not to say @40,000+ rpm it is pushing the limits on everything---that said, recently there is a BIG thread demystifying the so-call forbidden RPM ZONE ( 40,000 and up). So I am not going to yank this one or attract any attention that will mess up your thread. Read it yourself and may be it will be informative for you at this time since you are beginning and not corrupted in any way, form your own conclusion.
What I have learned is that for a 26" hull, there is definitely a limit for speed, and the size of your prop. Too big a prop and you will have torque roll. I really have a hard time agreeing with that guy's claim that the boat was reaching 50's. But I am not there and I can't prove my theory.
Another thing, have you seen the prop shaft? Is it 3/16" with dog drive or is it a solid shaft with 4mm thread? That dictates your choice for props. I am just as impatient as you are, but you will be more frustrated if your boat is in front of you with a pile of wrong parts.Too many boats, not enough time...Comment
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Found the 40,000rpm thread, I'll read it in a minute. This is getting interesting.
Judging by mail tracking info, I should be getting the hull tomorrow. Right now I'm leaning towards what you are suggesting: finding out if I have space for 4S, and going with the 36xx 2200kv motor if I do. Otherwise I'll get the 26xx 3400kv.
Also, I re-visited the 3 battery links you posted above, and saw that for that particular battery brand, the physical size difference is only in the height (for 5000mah): 2S is 19.5mm, 3S is 29.5mm, and 4S is 39mm. My question is: is there any difference between running 2 x 2S compared to 1 x 4S ?Comment
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If your hull is shallow, you can always put two 2s side by side, one 5000 4s is twice the thickness and chances are that you won't be able to close your hatch.Too many boats, not enough time...Comment
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Fair enough, I'll do the measurements tomorrow, hopefully there will be space for two 2s's.
I just realized I have no idea what prop to use (be it with the 3S 3400kv or the 4S 2200kv). That guy on the ebay with the same boat, which was hopping like crazy, wrote in the description that he has a 35mm x 1.4 copper propeller. My hull will come with a plastic prop (don't know the size yet), so I'll want to include a couple of props with my order to start with. But I have no idea what's a good size to start experimenting with. I imagine one day I'll have a set of a few props in my collection, but that day has not come yet
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You have to look at the business end of your shaft, if it had threads, it's probably 4mm thread, like most RTR in that category, if not, then you need to see the diameter of the shaft and determine if a 3/16" prop meant for a drive dog is used. This link is for Balanced/sharpened/polished props: http://www.offshoreelectrics.com/pro...Balanced+Props
There are different shaft sizes in addition to different prop sizes.
I would not run anything larger than a 40mm prop to begin with.
If you have a threaded shaft, you may use these CF prop, they are not bad. http://www.offshoreelectrics.com/cat...led+Propellers
My info. is probably on the long winded side---bad personal habit, my point is that you have to see the shaft first to know what type of prop/shaft interface you can use.Too many boats, not enough time...Comment
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Tlandauer, thanks for the prop tips and links. I'll review these shortly and make my shopping list.
The hull came. Here are all measurements I thought are important. Looks like I can fit a 36mm motor with 25mm spaced M3 screws. Not sure about batteries, especially if I have to keep them more to one side....I'll think about it, just want to post the pics here right now:
Sturdy transom:
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