Harbour directory

Dumas MISS UNLIMITED KIT #1305

Listed by samc ·

Specifications

Boat Length
26" (66.04 cm)
Motor Type
Brushed
Drive Type
Direct
Props
Single
Battery Type
LiFe
Run Time
353 min
Model Speed
377 km/h (234.3mph)

Photos

About this boat

This is the third dumas model i have bought and working on. For some reason i like this Hydroplane the old style types,. I had heard this was not a very good kit, alot of work to get it finish, and they were right. the instructions, are just about useless, parts are all ( one good point) over sizes. but that said, it is hard to figure out what and where the pieces go and fit. Driving me crazy trying to make a nice working model, but not sure where and how parts go/ lint up, or the intended of the drawing is suppose to be. Dumas email me back, just said it is an old model and will not be made any longer. thanks.
Not sure about the motor. looking at 600 - 800 brush type motors. that is what i have experience with as of now,. Not sure how brushless motors are rated. yes i have read the how and what the numbers mean, but i'm not sure how i can convert that to a 600 type motor.. any help would be of great h... i'm not going to race this, no clubs around here. I just want it to go up on plane, not 60 MPH. I'm thinking that a 600 type will do the job, also have batteries and a ESC for brush type. but i have been looking into burshless and trying to get educated on what all the numbers mean...
that are no charts to convert over so i'm asking if anyone have a good working knowledge on how you pick out an burshless motor... thank you.⚡

Comments

  1. CB90
    Captain
    This is a quick basic guide.
    For a hydro you should go brushless, as more efficient, more powerful, than similar size brushed motors.
    Generally avoid sensor controlled, go for sensorless as they will run on many more brushless speed controllers.
    (Quick note brushless motors can only run via a speed controller do not connect directly to a battery, another way to kill a brushless motor, is to run it with no load, so connect it to a prop shaft).

    Generally there are two variations on brushless motors, in-runner which look like a brushed motor but you have 3 wires, and an out-runner which has the outer casing moving.

    Physical dimensions are as follows:
    In-runner 3650 = 36mm diameter and 50mm long similar size of a 550 brushed motor.
    examples 2860, 3660, 4290 getting bigger.
    can add water cooling via jackets or copper tube.

    Out-runners generally have more torque, but can only be water cooled via a special engine mount.
    https://www.ebay.co.uk/itm/MOTOR-MOUNT-WATERCOOLED-BRUSHLESS-brushed-28mm-to-36-540-600-rc-boat/390949237673?hash=item5b0663f3a9:g:TYcAAOSwDM5e405d
    physical dimensions are as follows:
    2212 is 22mm wide and 12mm long
    6384 is 63mm wide and 84mm long

    ok now a bit technical Torque of brushless motors is shown by KV
    example 1500kv this mean it will spin at 1500 rpm per 1volt applied so on a 7.4v lipo it would like to run at, 11,100 rpm, but will not under load.
    The lower the number the greater the torque assuming same power motor.
    In practice I have found you can get good results from a wide range of KV from 1000 to 4000.

    If you run on 7.4v assuming prop fully submersed I have used a
    RCECHO LEOPARD Model 3536 KV1520 RC Outrunner with good results with a 36mm prop. on a 24in/60cm boat retail at around £25.

    https://www.amazon.co.uk/LEOPARD-Outrunner-Brushless-Propeller-RCECHO/dp/B00EQTTJI0/ref=sxts_sxwds-bia-wc-p13n1_0?cv_ct_cx=outrunner&dchild=1&keywords=outrunner&pd_rd_i=B00EQTTJI0&pd_rd_r=bf3b322c-b81f-4810-bf27-d5c603344fe8&pd_rd_w=IwqPF&pd_rd_wg=N0xcy&pf_rd_p=9b1a9511-9af9-4d06-8643-d54ebec511ef&pf_rd_r=30MVDB33NBVDPXSQTW45&psc=1&qid=1597159924&sr=1-1-fdbae751-0fa5-4c0f-900b-865654896618

    Your speed controller (ESC) need to be over spec at least double the motor current rating especially ones from china.
    This one should be OK.
    https://www.amazon.co.uk/gp/product/B082SSKWQK/ref=ox_sc_saved_title_10?smid=A3VARKKFF1JJQO&psc=1

    Final note I hope these note are useful to you, It is a complex subject and can get technical.
    I am sure some one will have a differing opinion, If your unsure run the boat on what you have, and upgrade later, a lively boat takes a lot of concentration to drive and patience to set up correctly.
    Liked by Joe727 and RNinMunich
  2. Newby7Bronze
    Fleet Admiral
    I build the Dumas Geo. w. Washburn.
    It turned out a good boat but some parts and directions were not that good.
    Your build will also turn out well I'm sure.
    Rick

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