2 mini monos 50 cm (Far east kit)

Discussie in 'Speedboten' gestart door Dim L, 25 dec 2022.

  1. Dim L

    Dim L

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    Good morning rc friends and Merry Christmas! :beer:
    Santa Claus came to our home early in the morning and brought 2 mini monos wooden kits from far east for the kids...
    He also brought two stringer kits with axle propellers etc...
    Boys started building their kits immediately and they wanted to show their progress in this post... (a fast forward construction video will also be available asap)

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  2. Dirk Jan

    Dirk Jan Forum veteraan

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    Merry Christmas to you as well! Nice project Dim. This hull is actually derived from the Wildthing .
    Looks like a lot of fun, together with your sons. I have 2 sons as well and they like to drive my Tamiya's occasionally, but so far they are not bitten with the rc virus, like me . Never mind though!
     
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  3. Dim L

    Dim L

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    Wow Jan you recognize it immediately...I am impressed ;). Indeed it is a copy of the wild thing and I love it. For 23 euros each I think it is a good deal given that the plywood is of high quality and the parts are accurately cut.
    Regarding the boys I bought them two traxxas rustler 2 years ago and they got infected... ;)
     
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  4. Dim L

    Dim L

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    Goodmorning rc friends. Let's check out today's progress. The hulls have started to take their shapes and we are all very excited.

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  5. Dirk Jan

    Dirk Jan Forum veteraan

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    The more I look at it, the more I realize what a great deal this is. You get the DIY fun, and it includes all the ribs and plating for a great price.
    50cm is also a nice size to run at smaller ponds, the setup is affordable and you can still reach high speeds.

    What kind of setup are you going to use?
     
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  6. Dim L

    Dim L

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    Yes Jan this is true, it is a great price for a laser cut kit.
    The setup will be:
    Motor: Rocket 2958 3350 kv (I found a good deal with 31 euro including the water jacket)
    Esc: 90 Amp colorfly
    Battery : 2s lipo 2200 or 3000 mah.

    I know that the motor may be somewhat big but it's price it was so tempting...
     
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  7. Unusual RC

    Unusual RC

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    On 2S these might be well suited!
    More torque is never a problem ;)

    In the 80-ties the 500/600 7 cell class of boats was all that I could afford. Tuned motors could generate a "blistering" 150 Watts of power!
    50cm was often the size for a mono!

    I could put them in my backpack and peddle-bike to most ponds with it.
     
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  8. Tbird2

    Tbird2

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    As a side remark....
    I love the way you devided the build area in 2.
    Port: Nasos
    Starboard: Peter
    Prevents mixing parts and prevents arguments.

    Maybe a good idea to buy some blue tape for myself at home, may prevent a lot of arguments... Joking surely.

    But great building together, have fun!
     
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  9. Dim L

    Dim L

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    Haha your comment is so successful... You describe the reality accurately...

    Sure it is fun to build altogether. Thank you for your nice comment:thumbsup:.
     
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  10. Dirk Jan

    Dirk Jan Forum veteraan

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    Your setup sounds great. Enough motor for bigger props, if your boys have the need for more speed .
    Great deal for that motor for 31 Euro
     
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  11. Dim L

    Dim L

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    Happy new year to everyone! I hope you had a nice new years eve.

    Santa came again last night and what a surprise, he brought two 2958 3380 kv watercooled brushless Rocket motors. :D

    We also had our first fiberglassing session. The edges of the inner were fiberglassed with a fiberglass tape. The hulls have become quite strong since the kit uses 2mm ply for plating but the edges need to be reinforced.

    The space is very limited and positioning the motor, esc and lipo would be challenging.

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  12. ardmuijlwijk

    ardmuijlwijk

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    nice build, only one sugestion: i would sheck first the motor whit coupler, and let the motor run easely, before you put the motor in the boat, iff i am not mistaken these couplers are all vibreating beatly, this will not help to run a smoatly boat.

    I have more than 10 off these coupler,s and are replace them all, not one was running good whit this coupler, so i would check first iff these coupler,s are running nice, iff not replace them whit better one,s. The vibration is feeling not good when you place the motor in youre hands, it is not a litlle bit, but very anoying, by a little bit and more revs. To compare let the motor run whitout the couplers and notify the difference, then you know right away where the problem is.

    Whit my miss geicko same problems, and did have to replace all bearing,s off the motor,s, the vibration is the reason why. good luck, gr.
     
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  13. Dim L

    Dim L

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    @ardmuijlwijk thank you very much for the suggestion :thumbsup:
    !
    I have not used these couplers before and I thought it was a good choice.

    I will test them as you suggested:thumbsup:.
     
  14. Dim L

    Dim L

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    Good morning rc friends!
    We had some progress this morning. We opened the holes for the axles and we mounted the stringer.

    The motor will be positioned at the very front and the batteries and esc at the middle. This is the only plausible set up given the size of the hull. Fortunately a normal sized lipo 2s - 3s lipo of 3000 3500 mah is easily fitted. A mini servo will be used for the rudder.

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  15. Unusual RC

    Unusual RC

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    No access anymore to the motor?
     
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  16. Dim L

    Dim L

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    Oh no it is not glued yet and of course we will cut the deck to have access to the motor!
    So sorry I scared you ;)!
     
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  17. Unusual RC

    Unusual RC

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    LOL!
    You would not be the first to do so :D
    Glad you are making an additional hatch!
     
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  18. Dirk Jan

    Dirk Jan Forum veteraan

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    Looking great Dim! And familiar as well . The original bulkhead design might be more limiting in ways of placing the components, but I think your layout works fine. Did you check if you can get the centre of gravity right? You probably did
    I wonder what kind of rudder you are going to use? Make sure to put it in such way, that trim tabs can still be fitted underneath.

    Looking forward to the next update
     
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  19. Dim L

    Dim L

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    Thank you Jan :)!
    I love its design.

    Indeed, the bulkheads are very restrictive. I told my boys to remove the center bulkhead but they said a big No. They were afraid that the hull would collapse... so I obeyed...;)

    The center of gravity it is just fine with a normal 3s 3300 mah and there is also room for extra adjustments. The Esc can also move along a line of 6cm so I am ambitious that we ll find the optimum position.

    By coincidence yesterday we ordered the following ruder:
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    I think that a trim tab still fits underneath.

    My problem is that I cannot find small trim tabs to fit the size of the boat (possibly 20mm x 25mm). An adjustable diy trim tab is difficult especially if you work with stainless steel.
     
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  20. Dim L

    Dim L

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    Hi again monohull racers!
    Below you will find a very interesting article by John Finch that I came across as I was searching for small trim tabs.
    Please pay attention to last section "Top secret tip".


    Monohull Speed Secrets
    2012-09-09 23:37


    Speed Secrets for Monohulls
    Today Monohulls reach speeds of 65mph on the racing circuit and do it with more control than ever.Twenty years ago monohulls were labeled “rock boats”because they rocked uncontrollably from side to side down the straightwayat top speeds of about 35mph.The evolution from rockboats to high-speed racing machines is a result of a team effort in which modelers have worked hand in hand with boat and hardware manufacturers.Engines that are hot right out of the box and greater selections of racing propellers have taken speed to a new level that demands properly trimmed boats.

    Deep-Vees

    The reality of heat racing is that after two laps,the water gets rough no matter how calm it was before the race started.The boats have to run well in rough water,so deep-vees are the models of choice.They have a deadrise angle of 16 to 26 degrees,which is great for rough water ; at top speeds on calm water,however,they can also “air out”. The hot deadrise numbers today are 21 to 24 degrees.

    [​IMG]

    I have tried up to 26 degrees but have found that rudder action from slow to high-speed transition is not linear.Anything less than 21 degrees and you stand a good chance of rolling over in choppy water because the boat bounces rather than cuts through it.

    Trim Tabs

    Trim tabs are used to adjust the ride angle of the model.

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    They are usually mounted on the transom about halfway between the keel and the chine.The inside edge is usually about 1,5 inches from the keel.Some trim tabs are single-tab designs (one on each side of the hull);others are split into two adjustable plates.

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    The double tabs allow two separate adjustments for each tab.With a two-tab setup,the innermost tabs are adjusted up and down to raise or lower the bow.Adjusting both tabs downward pushes the bow down because the water leaving the tab’s trailing edge lifts the transom.Raising the inner tab’s trailing edges reduces this lift and allows the boat to run higher (lighter) on the water.

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    The inner tabs have a second function as well.They can make the model lean left or right depending on the “right-vs-left”adjustment of the tabs.If the boat leans to the right because of engine torque (and it will),the right (starboard) tab should be adjusted downwards.This will lift the right side of boat.Keep in mind that lowering the right tab not only lifts the right side of the boat but also causes the bow to be pushed down.If the boat is leaning to the right and also running very wet (bow down),it would be better to raise the left inside tab to both loosen the bow and lessen the lift on the left side.Most hulls that are set up properly for heat racing are adjusted with the left tab level with the bottom of the hull and the right tab about 1/16 inch down.If the bow rides too light at this point ,both the left and right tabs should be adjusted downward the same amount to push the bow down.The right tab would still be down 1/16 inch more than the left one to compensate for torque.While running straight ,the outer tabs have little effect on the boat’s ride.They do,however,adjust the boat’s ride through the corners as the hull leans left or right.A monohull slides as it turns ,and if the bow digs in,the boat will turn more sharply.Pushing an outer tab downward makes the model turn tighter on that side of the hull because it lifts that side of the transom.This in turn, pushes the bow into the water with more authority but only during a turn.The right outermost tab adjusts the hull’s ride for right-hand turns and the left outer tab adjusts the ride in left-hand turn.Raising the outside tabs makes the boat less sensitive in the corners because it’s bow will ride higher (lighter) on the water.

    [​IMG]



    Fiberglass Hulls

    Many fiberglass models I have worked with are too sensitive in the corners because the hulls tend to warp as they cure.This causes a cup or “hook” to form at the transom’s upper outer edge close to the chine.The hooked surface of the hull bottom acts like a trim tab and will cause the boat to turn more sharply as it leans into the corner.Some boats don’t use trim tabs at all because they use a hooked hull bottom and a more forward CG position to balance the boat’s ride.

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    You should definitely use the manufacturer’s hardware designed for a non-trim-tab equipped boat.Most manufacturers tune their hardware to make the boat work with it’s natural hook and CG placement.Generally speaking , the CG placement for non-trim-tab boats is from 34% to 36% of the hulls length I front of the transom and between 28 to 31% for boats equipped with trim tabs.



    Top-secret tip

    There is an area of the boat’s hull that,to my knowledge,has rarely.if ever,been mentioned in any publication before.It has the biggest influence on trimming a mono at today’s higher speeds.It is the area on the bottom rear portion of the hull at the transom that extends from the keel to about 1 inch up the transom toward the side of the boat at the very last ¼ inch of the transom of the boat.It is the place where there are no trim tabs.It is a super-critical area that not only controls how high or low the bow rides but can also control the left to right balance of the model.The tricky part of this area is that it works totally opposite to the trim tabs.A hook on the ride side of the hull in this area does not lift the right side of the boat like the trim tab does but rather “trips” the boat into leaning to the right.If you want to see how this works, trtm your boat normally,then put a couple of drops of cyanoacrylate glue on the rear portion of the hull at the transom to form a 1-inch strip running outward from the keel toward the chine.The boat will then lean to that side and run “more wet” at the bow.

    [​IMG]

    Article from RCBM by John Finch
     
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