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Thread: Long term project 51" mono proposal

  1. #1
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    Default Long term project 51" mono proposal

    I am looking at a long term project involving a 51" mono hull "King of Shaves" with the bare hull available from Hong Kong. Obviously, 1/4" drive would be essential, but would a single 56XX series motor (say a 5692) have enough grunt to propel such a hull size. First task would be a carbon fibre inlay before adding mounts, etc.

    I would be thinking running a 240 - 300 amp ESC and 6s (probably 2 X 3s packs). Would a stinger or strut be the preferred option plus a propellor diameter to start testing with, please? I need a few answers to cost out this project.

    Edit: searching Google images lead to this small thread

    https://forums.offshoreelectrics.com...IN-P1-Powerbot

    Also found this -

    https://forums.offshoreelectrics.com...7cm-Twin-Setup
    Last edited by Old School; 11-20-2017 at 10:18 PM.

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    good size hull. have you had a look at Sonic Racing,s web page ? Danny is the owners name , he is local and has been in the r/c boating scene for a good 30 years. his hulls are mainly gas power designs but i am sure he would have a nice 50 plus inch offshore mono hull available in glass or even carbon fibre. hey you would need more battery power than a 6s for this size rig. [ 12s ]

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    12s is a lot of voltage, probably more than I care for. Pity

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    you must remember your also talking a big boat.

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    Yea, 12s minimum!

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    10S is MORE than ample...having built several that size. As its a scale hull, I'll assume that you want some speed but not stupid crazy fast...55 on a boat that size is pretty fast.

    Get a motor around the 700 (ish) KV. A Leopard 56 110 would have more than enough grunt for that hull.

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    Many thanks, I am only after a 'modest' speed and around 55 sounds about right.

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    Doby is correct...... did I just say that !! 10s 2p 5000mah per lipo pack. hi 60's, low 70's for roundy round, my DF Sniper 45" 19lb all in.

    Cheers, Jay.

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    i have a deltaforce inniliator 53, running a cocr bj-1 prop high 70,s. only issue is its powered by liquid fuel . i think total weight comes in at around or under 15 pound max.

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    Many thanks gents. While liquid fuel is nice, I prefer the noise a brushless makes when it screams. The gas motors remind me of lawn mowers. 10s 2p would I presume involve four packs with two each in series and then each set of two paralleled.

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    Quote Originally Posted by Old School View Post
    Many thanks gents. While liquid fuel is nice, I prefer the noise a brushless makes when it screams. The gas motors remind me of lawn mowers. 10s 2p would I presume involve four packs with two each in series and then each set of two paralleled.
    yup...

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    Quote Originally Posted by jaike5 View Post
    Doby is correct...... did I just say that !! 10s 2p 5000mah per lipo pack. hi 60's, low 70's for roundy round, my DF Sniper 45" 19lb all in.

    Cheers, Jay.
    I usually am....

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    Just not sure where all you guys are relating higher voltage to stupid fast speeds. You guys realize, it can be set up at a higher voltage to pull lower amps, increase runtime and make the whole electrical system much more reliable. It would seem that many of you just follow voltage/setup templates of others and don’t really understand the volt/amp/Watt/Kv/prop relationship. That’s fine with me, but insulting others because of your misunderstanding just ain’t looking so good from where I sit.

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    Craig,
    I did not see what was being said as insulting and I am sure no one intended any insults as such. When using 12s would you prop down to limit amp draw? As ESC are not intended for partial throttle demands then how does a higher battery voltage impact on the boat without increasing its speed, please? As a battery will cost me around $125.00 each (5000 mah 6s) and I would need four then potential voltage requirements for the boat may be the killer of the project. Theoretically without a duplicate set of batteries I would be looking at about a seven minute runtime per day allowing for batteries to recharge overnight between runs.

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    Quote Originally Posted by CraigP View Post
    Just not sure where all you guys are relating higher voltage to stupid fast speeds. You guys realize, it can be set up at a higher voltage to pull lower amps, increase runtime and make the whole electrical system much more reliable. It would seem that many of you just follow voltage/setup templates of others and don’t really understand the volt/amp/Watt/Kv/prop relationship. That’s fine with me, but insulting others because of your misunderstanding just ain’t looking so good from where I sit.
    Duuhhh...well...golly gee...why didn't we all thunk of that, high volts and not so much current....??? You iz so smart...the rest of us just follow'in blindly along not know'in what we iz do'in.

    10S is more than ample..Yes..12S would reduce current even more...but then lets run 20S and have even less. 12S=more $. Just trying to save him from spending money thats not necessary.

    Oh, and no-one is insulting anyone on this thread...

    Until you posted

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    no doubt you would use the same size esc for 10s and 12s power set ups so the esc is right to go. now is there much difference between a 5s pack and a 6s pack ? are the 5s packs harder to come by ? i have seen many more 6s packs available than 5s packs . what do you,s think ?

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    I had a quick look at Hobbyking and Turnigy Graphene 5s (5000 mah 65C) are readily available as are 6s packs.

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    Quote Originally Posted by Old School View Post
    I had a quick look at Hobbyking and Turnigy Graphene 5s (5000 mah 65C) are readily available as are 6s packs.
    If you're getting Turnigy Graphene packs, now is the time as HobbyKing is having a sale on their batteries

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    Quote Originally Posted by rol243 View Post
    no doubt you would use the same size esc for 10s and 12s power set ups so the esc is right to go. now is there much difference between a 5s pack and a 6s pack ? are the 5s packs harder to come by ? i have seen many more 6s packs available than 5s packs . what do you,s think ?
    You are right about the price difference...but everything adds up with cost and weight etc..

    Food for thought...if you ever plan on running (or do run) 4S boats, consider buying 6S and 4S packs= 10S...gives you a bit more options for the future.

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    Quote Originally Posted by Old School View Post
    I had a quick look at Hobbyking and Turnigy Graphene 5s (5000 mah 65C) are readily available as are 6s packs.
    When you are considering higher voltage setups, high highest C ratings are not always required, especially if you are just blasting around the pond and having fun.

    My 10S race boats have been purring away happily for the past few years on boring old Turnigy 5S 30-40C batts. Remember, when you parallel the packs, they "share" the load.

    Just a thought on potential cost savings.

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    Exactly Doby! I’m running some used racing batteries, put them in series instead of running them in parallel like the guy I bought them from, and get great run time. A 30C, 5000mah Battery is plenty on a 100A max draw. If your running 8s, that’s 3000W to work with, not bad for a 34” hydro. I try to keep my amp draw at 100, and design the other things around it. A 51” Mono is going to take some Watts to push it with enthusiasm. I was figuring 6000W on that, so that would be 135A at 12s, that’s why I endorsed that. 5000w gets you down to 112A. Sorry I took the “stupid fast” comment personally, was probably not directed that way...

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    Many thanks gentlemen, a lot of information to absorb.

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    Further reading in that these hulls seem problematic. Firstly, they are a thin construction and obviously require a full layup. Secondly, the hull is untested and it seems the hull suffers from bow steering. This has been "blamed" on either a hook in the rear step and secondly the rear stepped platform is poorly designed in that it should be a relatively flat side on view (refer prototype photographs) whereas the hull extends downward from the rear step to the transom forming a wedge shape. This acts like a permanent trimtab, causing the stern to lift with a resultant spinout. The effect is much like broaching on a sailing yacht.

    The suggested remedy is to cut the hull from the transom to the rear step and remove about a 1/4" wedge to allow the rear platform to assume a flatter stance. As the hull requires considerable reinforcing, the remedial action is perhaps not that drastic. I have yet to actually see a completed DT 51" mono hull project.

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    https://www.youtube.com/watch?v=r-1zGE65YMk

    I'll assume this is the hull in question...looks good on the water.

    IGNORE the stupid speed claims as the "company" G Freak is the equivalent to the Beavis and Butthead of the FE world.

  25. #25
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    Yes,
    that is the hull. May be purchased on evilbay or direct from Toucan Hobbies for a few dollars less. I notice that Beavis and Butthead did not even reinforce the hull and yet claim 90 mph. The hull is primarily a gas powered hull designed for 26 - 30 cc motors.

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    While I would prefer a P1 mono, the possibility of uncontrollable bow steering has me concerned. My son prefers cats and as it will be a long term project for both of us I am now heading more along the lines of a 51 inch catamaran. A video online with the stock LP 4082 twin setup shows a very stable hull and a GPS of 68 mph. For an old guy that is more than enough excitement. No doubt my son would rather extract more speed.

    The stock hull would be purchased and reinforced then fitted with twin TP Power 4050 or 4060 motors around 1200 - 1400kv. I would prefer a 6s limit per side. If insufficient voltage then perhaps a lower kv motor setup.

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    how about a 50 inch aeromarine twin offshore cat hull. [ hobby supplies melbourne ] these have good length and a decent width and there a proven hull.

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    At roughly $600.00 and who knows how much for courier postage given the size of the package, the hull is twice the price of the Chinese model. Personally the design looks more like a mono deck on a cat hull. The Chinese hull will require reinforcing and this will add cost, but that is the fun of building it to run fast.

    I know little of gas boats but going on videos seen on You-tube gas powered boats do not seem to have the pace of FE and I wonder if the Aeromarine hull is up for the job. In this video the stock DT boat with twin 4082 brushless and 120 amp ESC's looks very stable at almost seventy mile an hour.

    I appreciate the quality of the Aeromarine products and thankyou for the suggestion but it does not really suit me.

    One minute into this video is the stock DT51E. Very impressive.
    https://www.youtube.com/watch?v=wxrdY7hFgzc

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    Would 1/4" flexshafts be needed for a 51" catamaran hull please? If not essential would they be preferred given that I am thinking using twin TP Power 4070 with 8mm shaft. Would a flexshaft with the stub shaft turned down to 3/16" be preferable as it would allow a better selection of propellors.

    The "factory" boat uses a 45mm prop however this seems small for a 51" cat hull.

  30. #30
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    yes i would go for the 1/4 inch shafts with the stub turned down to 3/16 as you can always sleve the stub if you need a 1/4 inch prop. in the octura prop range , the largest 3/16 prop is a 65mm then comes the 1/4 inch 67mm and up.

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