|||
Current Website Support
256
Contributors
10
Subscribers
You are Not Registered
Donate for your silver medal ๐Ÿ…
ยฃ10
ยฃ15
ยฃ25
ยฃ50
Subscribe for your gold medal ๐Ÿ…
ยฃ1
ยฃ3
ยฃ5
ยฃ10
You Will Be Helping Towards:

  • Domain Fees
  • Security Certificates
  • iOS & Android App Fees
  • Website Hosting
  • Fast Servers
  • Data Backups
  • Upkeep & Maintenance
  • Administration Costs

    Without your support the website wouldn't be what it is today.

    Please consider donating towards these fees to help keep us afloat.

    Read more

    All donations are securely managed through PayPal. Amounts donated are not published online.

    Many thanks for your kind support
  • Join Us On Social Media!
    Save £50 when you join Bulb
    Model Boats Website
    Model Boats Website
    Home
    Forum
    Build Blogs
    Media Gallery
    Boat Clubs & Lakes
    Events
    Boat Harbour
    How-To Articles
    Plans & Docs
    Useful Links
    Search
    Search
    Blog
    The motor cover.
    I want to keep the motor cover as compact and in proportion as much as possible so I drew up a design to visualise it and get some practical working dimensions, it also needs to enclose the prop shaft and coupling, and the MT60 connection for the motor so there will not be very much free air space inside. Because of this the motor cover will need some ventilation as the brushless outrunner motor canโ€™t be water cooled and I donโ€™t want to fit a fan, so the side panels of the box will need some gauze covered slots so that any heat generated can escape, assisted (perhaps) by the
    rotation
    of the motors outer โ€˜rotorโ€™ creating some air movement. I donโ€™t intend to run this boat very fast so Iโ€™m hoping that the motor will not get too hot anyway๐Ÿคž. I transferred the dimensions of the side panels from my drawings to some 1.5mm obeche panels and cut the side pieces to size and cut out the ventilation slots, some framing pieces and cross braces were fitted internally and the whole assembly glued and clamped together. Additional framing was added to support the part that covers the shaft and coupling and obeche panels applied to these. Some finishing details were applied around the base and the top to improve the appearance. The internal framing will later incorporate some small cylindrical neodymium magnets that will hold the motor enclosure down on the deck, Iโ€™ll fit these later when the deck floor has been fitted. The mesh is some of the stainless steel mesh that I had used in the water pickup tube on my RAF Crash Rescue Tender hoses, and this was cut to size and epoxied in place. The completed enclosure was finished with the same Teak stain as the rest of the boat. Next up will be an enclosure at the rear to conceal the control electronics.
    8 months ago by robbob
    Forum
    Props - dumb question?
    The down side of prop
    rotation
    is that the Europeans use one method of defining it and the Americans use another - and they are contradictory. From the Prop-Shop site "Please note that propeller
    rotation
    is based on the British and American standard (viewing the boat from the stern) which is the opposite to that in Germany." See https://www.modelboatmayhem.co.uk/forum/index.php/topic,35415.msg418661.html?PHPSESSID=svi2h5353cc8fjds8h7krcqnh0#msg418661
    8 months ago by DodgyGeezer
    Forum
    All hooked up, nowt happens...
    Hello all, since I keep the weekend for me I thought I'd try hooking up all the lecktrickery for my brushless motor. It's one of they outrunning tiddlers. I have a 3S LiPo which is firing on all cylinders at 3.79 volts per. I plug it in to the ESC, some Chinese one I got recently. I soldered wires to a T type plug that fits the Overlander battery pack. I'd already soldered the 2mm connectors to the other end of the ESC wires and protected them with heat shrink. Plugged tested (6.2 volts) Nimhs into Rx and it starts flashing, then plugged ESC into a channel and the motor, yes , the MOTOR starts beeping! How the hell can that happen? I plug the battery in and the motor beeps even quicker! What on earth is happening? Needless to say, no
    rotation
    , buzzing, whistling, just beeps from a motor, clear as you like! Please help. I am already teetering on the edge of getting rid of all my working stuff as it takes up space and is such a damned faff! But what I have, I would like to work. Just long enough to prove it all. Martin
    11 months ago by Westquay
    Media
    March'71
    165footer job from Bangladesh navy. Armed with 1 37mm Chinese naval cannon (which I replaced with type 76F variant), 2 orlicons. Actually used to patrol costal area here , also used in coast guard. The class name is padma class patrol vessel, designed and made by BN. Tried to make its rc version in 1:110th scale(I'm not great like you guys so please help me do better and suggest me where I can do better). Length 45cm, beam 7cm. Powered with dual 180. The only thing I'm suffering is motor shaft connectoล•. Those two universal joints I bought are not good enough for smooth
    rotation
    . They vibrates. So I used silicone tubes. Now I'm using latex rubber tubes . Any suggestions or plan what I can use in peace!๐Ÿ˜†
    11 months ago by Sakibian
    Forum
    All hooked up, nowt happens...
    Arun now sorted. Programming card did not work so I translated the pidgin english instructions for the ESC and it worked using the Tx. I now have forward and reverse, correct prop
    rotation
    and no battery protection. Also the water cooling system for the ESC works with the water exiting from the exhausts on the stern. On the down side the nav lights have stopped working! Pictures of installation and finished boat later.
    11 months ago by rapidair65
    Forum
    fuse holder
    I agree with using the ones from component shop. They do single and two gang and as well as using auto fuses (Halfords) the holder has an led that shows red or green depending on motor
    rotation
    direction.
    11 months ago by Manofkent
    Forum
    All hooked up, nowt happens...
    You're as BAD as me Boaty ๐Ÿ˜‰ but I had a Rover 2000 with fully reclining seats back then - no problem ๐Ÿ˜ Re 3 wires on a brushless. Simply put, this is analogous to a 3 phase AC motor (such as used in bathroom extractor fans etc). If you apply a single phase AC voltage to an AC motor it just twitches backwards and forwards in the same place as the voltage crosses from the positive to the negative half cycle. Thus 3 phases are applied giving 3 'shoves' in sequence to keep things moving. A starter capacitor is also needed to give the motor a 'belt' to shove it off. Similarly with a brushless: the ESC senses where the motor armature is in relation to the magnet poles and applies a DC pulse to the next armature coil in sequence. When you shove the throttle up the pulse width lengthens applying a longer shove and thus more energy and speed. Pulling the throttle back with a reversible ESC just turns the pulse train upside down so that negative DC pulses are applied to the motor, reversing the magnetic field created in the armature and thus the
    rotation
    . Simple really. It's the sensing and timing done inside the ESC that's the tricky bit, which is why we had to wait about a hundred years from the invention of the AC motor (Nikolai Tesla) until we could use them in models - thanks to micro-electronics. Here endeth today's seminar ๐Ÿ˜๐Ÿ˜ Happy brushlessing Folks, cheers, Doug ๐Ÿ˜Ž Hmmm, perhaps that's why electric toothbrushes use brushed motors! ๐Ÿ˜๐Ÿ˜œ
    11 months ago by RNinMunich
    Response
    Must get the skins on before I pull all of my hair out!!
    Hi Pete, Basically yes. There are some other tricks with twin screws, not least engine assistance using a twin ESC with rudder mixer. Also the screw
    rotation
    makes a slight difference, and the rudders are usually slightly offset from the shafts, depending on the screw
    rotation
    . Are yours turning outwards or inwards? Referred to the top of the screw looking from aft while going forward. Cheers, Doug
    12 months ago by RNinMunich
    Forum
    Help required on Boat i.d.
    Apologies for not correcting the
    rotation
    of the pictures.....
    12 months ago by Rookysailor
    Forum
    Got the bits, now what?...
    Hi westquay. that looks like a 2200 3 sel battery if it is and it has a black deans connector on it (they are usually yellow) in my opinion they are the best. XT60 if it is put a male xt 60 on the battery side of the esc and your own chosen bullet connectors on the esc to motor. I like to use ec3 or ec5 (depending on current draw) with a different coloured heat shrink seal, on each one. it helps if you need to reverse the the
    rotation
    of the motor. Take a look on line at the way the electric flyboys link it all together you will also get an idea of the connctions. Hope this helps. jimdogge
    1 year ago by jimdogge
    Response
    Rebuild starts
    Is it possible to fit new bearings in the existing shaft tube, if not I have managed to get old shafts out by carefully heating the tube using a soldering iron inserted into the end and as it heats up applying
    rotation
    al force gently back and forth until the the glue gives way. This has worked for me on wooden hulls. Cheers Colin.
    1 year ago by Colin H
    Response
    BRAVE BORDERER
    If you are using 2 ESCs/BEC/UBECs with 2 plugged into 1 receiver you should remove the red wire from one of the plugs and tape it back to the lead, as both plugged in will possibly supply too much voltage for the receiver (you are getting double the voltage from 2 different sources) and this can cause the ESC to stutter . You should have no problems with Brushless out-runner motors as with the correct match with the ESC they should be as smooth as brushed. I have dual 2000kv 28/45 in-runners (with water jackets) and twin ESCs and 2 sound units using 1 receiver in my 64ft ASR model with no problems regarding proportional control (fwd or rev). I had a 28mm O/R in a Maiami ASR and it would crawl along (but the high noise was ear wrecking so have changed it back to brushed for now. I do have a similar slight high pitched squeal at certain speeds on one motor and this may be caused by the particular motor not 'syncing'properly with the ESC (Chinese cheap ESCs and HobbyKing /made in china motors) but short of changing that motor and ESC I am just putting up with it for now. The high pitched sync noise is fairly common and sometimes not fixable, (a number of my larger planes do it and its audible from 100m away (also amplified by a hull,-nice sound box). it can depend on the way a particular motor is wound (no 2 are identical) or even magnet placement/timing, as the may be hand wound by 2 very nice Chinese ladies at different ends of a bench ( just read some of the Hobby King motor reviews ) You could try changing the frequency on the ESC if it has that option as a higher motor Kv sometimes requires a higher frequency. Also make sure your ESC is set to the correct battery cell count. if it has an auto setting that should usually work best for general applications unless you are running fancy motors. Regarding interference, make sure you keep your aerial as far as poss from the motors and ESCs (even on 2.4 - I put mine right up in the bow) and there should be no problems. I have had 2 twin engined boats (my MTB & ASR) 1 brushed and 1 brushless running side by side 10" apart using the same radio for both (same type of Rec in each boat) with no problems at all. The bow down is probably prop shaft angle (the shallower the better) but if you are using counter rotating props you could try swapping props (inward
    rotation
    to outward) and motor
    rotation
    to see if it makes a difference. Also with 2800Kv motors you should be using small props (around 28-30mm diam 3 blade) as these motors are made to rev) as on a 2s battery they will be turning at around 20,000 dry and perhaps 18,000 wet (depending on prop) and if you load them too much they will cook with no cooling (assuming they are around 28mm dia ?) Only other thought - silicone couplings will squeal real loud if they slip.
    1 year ago by jbkiwi
    Forum
    SLA Batteries!
    Hi Ed, I have MTroniks ESC's including a couple of PNP types. What I do is to start by moving the stick to reverse then back to the middle, (You can observe the direction of
    rotation
    ). Then to the top and back to the middle. This works. The SLA batteries have nothing to do with the issue.
    1 year ago by reilly4
    Forum
    What is the optimum prop shaft angle?
    Mornin' Ron, If you put the motor where the batteries are now - where will the batteries go? They weigh far more than the motor so moving them forward will push the CoG even further forward๐Ÿ˜ฒ Re shaft angle; as flat as you can get it for the size of prop you want to use. This is to reduce the forward
    rotation
    moment of the thrust which tends to push the bow down. The further back you fit the motor the larger the angle will inevitably become due to the space needed for the motor and mount! BTW: Why two NiMh batteries? I would be tempted to change the set up to a brushless and a single LiPo. This will significantly reduce the total weight as well๐Ÿ‘ You did say the boat is 'a heavy model'! ๐Ÿ˜‰ Doug ๐Ÿ˜Ž
    1 year ago by RNinMunich
    Forum
    ESC info...
    Or this one https://hobbyking.com/en_us/hobbyking-yep-60a-2-6s-sbec-brushless-speed-controller.html and it has Blocked
    rotation
    protection (senses a jammed motor and stops motor
    rotation
    ) ๐Ÿ‘ Get one of these to go with it so you can get the best out of the ESC and motor https://hobbyking.com/en_us/yep-esc-programming-card.html Ciao, Doug BTW: Some stuff might be out of stock at the UK warehouse but still available at the EU warehouse in Holland. You'll get the stuff just as quick from them and still duty free - until BREXIT ๐Ÿค”
    1 year ago by RNinMunich
    Blog
    Seat Trials and mods.
    Itโ€™s been a while since the boat had itโ€™s maiden voyage on the lake at St. Albans and Iโ€™m pleased to report that it looks really good in the water and goes like stink if you open up the throttle. Sadly I still donโ€™t have any decent video of the boat yet as I canโ€™t film and drive the thing at the same time, but I do have some static wide shots from my GoPro. When I do the video Iโ€™ll ask a cameraman mate to do the honours, maybe Iโ€™ll put the GoPro on the bow and then the stern to get some low action shotsโ€ฆthe storyboard is already building in my head!! These early runs were great as they showed up some minor problems that needed attending to. I found that it needed ballasting slightly as it was not sitting on the waterline evenly from side to side so I flattened out some old lead water pipe and cut it into small sections so that I could add ballast incrementally. I did this in the โ€˜domestic test tankโ€™ and once I was happy the lead pieces were fixed in place inside the hull with some super strong double sided tape. The ESC needed a little programming adjustment because I had forgotten to set the low battery level point to โ€˜offโ€™ as I am using NiMh batteries and not LiPoโ€™s , that was the cause of the short initial run time on the first outingโ€ฆ..DOH !! The batteries are now held in place by Velcro straps on some bearers that I added, otherwise a battery change involved cutting cable ties and replacing them at the lakesideโ€ฆnot very practical. The volt/amp/watt meter is also now on a proper bracket so that the display is more readable. I have also changed the charging connection from the nasty Tamiya connector to a nice little panel mount XT 60 connector that HobbyKing sell, it comes with a handy blanking plug that I have drilled for a retaining cord. I have also finally got around to upgrading the firmware on my Turnigy i6 radio to the 10 channel version so that I can assign the lighting to the switches properly and have the
    rotation
    of the searchlight on one of the two rotary knobs. I can use the old 6 channel RX in the new boatโ€ฆ.blog coming soon.
    1 year ago by robbob
    Forum
    RE ads90's Vosper Firefloat
    The real boats, perhaps oddly, all used same direction
    rotation
    . Martin
    1 year ago by Westquay
    Forum
    Spektrum, new, useless...
    Hi Martin, First your last question๐Ÿ˜‰ "What DO you do with a 3rd channel?" Example: 5 foot destroyer! 1 Throttle. 2 Rudder 3 Gun
    rotation
    , servo and pulleys 4 Torpedo tube
    rotation
    , servo and pulleys 5 Smoke switch, servo and microswitch (Smoke could be linked to the ESC to free this channel for the ASDIC pinger!) 6 Split into four functions (by misusing the gear down lever on my Graupner MC-10๐Ÿ˜‰) for Whoop whoop, Fog horn, searchlights and signal lights, NAV lights. All switched via a home brew decoder / switch board and 5V relays! Alles klar? ๐Ÿ˜‰ Re the DX5e; if I were you I'd let a (supposedly?) Spektum trained guy look at it first. With luck he'll have a service manual or at least a circuit diagram, which I don't ๐Ÿค” and should know the binding procedure backwards. I could only do some rudimentary tests without the circuit diagram, and make some educated guesses. I could at least try binding it with a variety of Rxs, including my Spektrun RXs which all work faultlessly with my DX6. Up to you, will PM my address anyway. I could at least check, with a simple RF meter, if the damn thing is transmitting at all! Just thought - if you're going to smash it anyway ........ ๐Ÿ˜‰๐Ÿ˜ Cheers, Doug ๐Ÿ˜Ž PS: 4th attempt at the prop shaft for the cutter also failed ๐Ÿ˜ก She just does not want to get her bum wet!! Too long 'on the shelf' ๐Ÿค”
    1 year ago by RNinMunich
    Media
    CB90
    CB90 Model boat, 52 inches long performing 360 degree
    rotation
    on its own axis. The Combat Boat 90 (CB90) is a class of fast military assault craft originally developed for the Swedish Navy by Dockstavarvet. Powered by two 9.6v Graupner 700 turbo motors (no-longer in production). Two Mtroniks Viper Marine 25 is a Brushed Speed Control designed specifically for use in RC model boats, it has a 25Amp motor limit and has proportional forwards and reverse functions
    1 year ago by CB90
    Blog
    H.M.S. BRAVE BORDERER
    An unexpected opportunity arose to try the unfinished hull in a small pool. Whilst the performance envelope could not be explored, was able to try and measure operating parameters and get a โ€œfeelโ€ for the model. Used an electronic scale and a combination voltmeter/ammeter/wattmeter to measure propeller thrust /bollard pull and motor power requirements. if it is necessary to fit different drivetrain components, or a 3S cell this will serve as the baseline. The model floated levelly and well above the waterline. At about 8 volts the motors drew around 20 amps each at full speed; so only about 35% of the potential output capacity was being used. Tested each motor individually and measured the bollard pull at just over 2 lbs. A considerable amount of spray and wash was created making stable readings difficult. For further testing, will add ballast at the stern to hold the propellers further underwater. Should help reading stability. Currently using 20 A fuses; which as one failed seem marginal. For sustained use think 25 or 30 Amp better. With these high-speed, low torque motors establishing the โ€œdryโ€ propeller
    rotation
    is deceptive. Found one motor to be reversed! Nevertheless, the model accelerates quickly and is sensitive to engine speed movements. Left the pool with a list of modifications to make before assessing the installation properly on an adequate body of water. Some conclusions can be made though. if it is necessary to add a second cell this needs to be located around midships, not in the bow or stern. Still hoping a 3S cell will not be necessary and that 2S may be adequate. The suggestion to do testing using the bare hull with a minimum of detail was a good one. For a models with a sophisticated power train think this is a good approach. Nothing worse that finishing a boat just to find the performance disappointing, then have to to rip it apart to make major modifications or adjustments!
    1 year ago by RHBaker
    Forum
    47'' Fireboat power question
    Hi Shaun, This design of hull forces the craft higher and higher the faster it goes. When it is high on the plane and almost hanging on the last few inches of propshaft it can fall off the plane either way, usually to the right (Starboard) side because of engine torque. The full size boats were fitted with 2 or 3 engines to help counteract this. The British Powerboat Company, who originally designed the hull that Vospers copied back in the 1930s/40s also noticed this which led to double skinning the hull with 1 inch thick mahogany for extra strength against pounding and falling on the waves. Lowering the drive angle of the propellor shafts and adding more weight from the C of G back to near the stern. We build this 3 screwed designed hull with one mainshaft usually so do not have the benefit of shaft
    rotation
    to stabilise the boat at speed. It was in the 1960's that Fairey engineers had the same problems (Swordsman,Huntsman etc) They came up with large transom mounted powered Trim Tabs. Their boats had similar problems and only one shaft in the main. I suggest you try fitting 2 x 2 inch wide by 1 inch deep trim tabs at the very bottom of your transom midway between the keel and the chine as well as move your battery packs forward a bit initially. Try some fast tests with this, you only need 2 to 4 degrees of down on the tabs initially. Add removeable weights near the CG as needed, a bit at a time but don't stop the bow lifting up onto the plane. Have fun, best of luck. Ron Rees
    1 year ago by ronrees
    Blog
    Cabin windows again
    Having remade all the front cabin window frames I then decided to fit the acrylics into the opening (nice tight fit) all done! Or maybe not, someone then said how about โ€œopening windowsโ€ itโ€™s been done before. So would opening windows be a problem with water ingress? And would putting foam seals solve this problem? Iโ€™m not convinced. Having given the problem some days thought, how about going with the windows as planned which are now 1.5mm thick and inset into the surround. Then fitting an over window frame 1.0mm ply/plasticard with another thinner (1.0mm) acrylic window and hinging this above each window. This would solve the issue of water ingress and also give the appearance of opening front windows. Looking at how one other person approached this, it looks like the hinge was a brass tube across the majority of the window top and then a shorter piece the same dia tube at each end with an internal wire for
    rotation
    these short pieces are then fitted to the body of the inner window frame. These additional window frames can be added at a later stage and this doesnโ€™t hinder the final finishing of the roof skins. So final fitting and adjustment and then pin and clamp in position the forward roof skins. When these are dry the window frames can be finally trimmed and then pinned into position and checked for fit then removed and then to each one apply the aliphatic glue and fit โ€“pin and clamp in position
    1 year ago by mturpin013
    Forum
    HMS HOOD by Trumpeter
    Even tastier with the Frankfurters, and Colemans Mustard I trust๐Ÿ˜œ๐Ÿ˜‹ Steve: I found a cheap way to mechanise the two aft turrets of my H class destroyer Hotspur, using one servo with a pulley, a couple of smaller pulleys on the turrets, about 2:1 ratio to give at least 180ยฐ
    rotation
    at the turrets, and a spring loaded nylon cord around the pulleys. I'll see if I can dismantle her over the weekend to make some pics. I plan to try something similar with my 1:350 Hood, also Trumpeter and also excellent detailing. Another way is to use one micro servo per turret, connected with Y cables if you want a synchronised Broadside; A+B and X+Y turret. Then use the servo travel adjustment at the TX to maximise the
    rotation
    . You can then move all four on one channel or two channels for 'Independent Firing" fore and aft. I will use the two pots at the top of the Turnigy i6 TX for this. On Hotspur I used the left stick left/right. I plan to do this in my Graf Spee, Belfast, Hood and Bismarck. Maybe also the ack ack turrets on Ark Royal!? Will knock up some test jigs sometime ๐Ÿค“ Cheers Doug ๐Ÿ˜Ž
    2 years ago by RNinMunich
    Forum
    Graupner ranzow refitting
    Here we have the working crane for lifting the buoy's into/out of the water. Again this was converted to working by using three micro motors rated at 300-1 plus one gear box at 5-1 to operate the
    rotation
    and a 4-1 gear box to operate the lift and lower first pic shows the crane completed second pic shows the line winch motor which is just a 300-1 micro motor. third pic shows the lift and lower arm with the motor and gear box is hidden in the crane body fourth pic shows the micro motor and gear box that controls the
    rotation
    , there is a similar layout that controls the lifting arm the final pic shows the micro speed controllers that you can do the fine control of setting the required speed that you want. Ron
    2 years ago by kmbcsecretary
    Forum
    Aerokits Patrol Torpedo Boat
    Hello RNM and others. The 20mm gun arrived today. I am really pleased with it. To my surprise, it does move up and down. it has no
    rotation
    al movement. I will attach pictures at the end. I bought the "beast" motor that you suggested Canabus. I will have to see how it fits in. Do you think the universal joints I am using now are suitable or should I upgrade these considering the RPM. One other question I have for today is about paint. Can you suggest a suitable paint to use on my boat. I am not concerned about the colour, just the type/make at this stage. I read an article here earlier that suggested to use Holts car spray cans. What are your thoughts on this. I have an air brush if this is more suitable, but would like help on a suitable paint choice. I will attach the gun pictures now. if there is a particular angle you would like, please reply and I will try to add tomorrow. Thanks. Peter.๐Ÿ˜‰
    2 years ago by MouldBuilder
    Forum
    Graupner Elke HF 408
    Hi Allen Mabuchi no longer list details of your motor and as it is from an ex flyer chances are it has been cooked at some time in its life. I agree it is not easy to check for shorts but a reasonable meter will show any major problems. Your battery sounds fine. Pitch is often marked on the props near the boss but an explanation I have seen on the web: Pitch: theoretical distance the prop travels on each
    rotation
    . This is theoretical because water is not a solid medium and the prop slips. 10 to 30% is normal, the lower numbers are found only on hi-performance props, specially prepared. Constant Pitch: the pitch is the same across the entire propeller's working surface, or blade face. Progressive Pitch: the pitch is lower at the leading edge and increases progressively along the trailing edge. Consider a prop that runs in a liquid media with a constant pitch, the tip of the prop rotates faster than the hub. Conversely, if the angle at the tip is lower, the water speed on all prop surfaces will be the same. in this case, the performance is far better. Progressive pitch props offer better planning performance. So if you were to get some graph paper or paper with 1mm markings and set the prop on a shaft over the paper and measure the start point then rotate thro 360deg and measure the finish point this will give you the theoretical pitch. Over the years I have amassed a fair number of props and usually try various before I decide on the best for the model. Try what you have with the 6v battery (looks just right for the model) and see how it sails. From experience I know that this type of model is difficult to get going and all our club models have coarse pitch brass props. Speed will depend on the motor but with a geared motor you should be able to reduce the revs to give scale speed. I look forward to hearing how you progress in a couple of weeks.
    2 years ago by Dave M
    Forum
    Graupner Elke HF 408
    Re Prop (or screw pitch) ... If the prop blade was a complete screw it would advance through a solid at the rate of NP, where P is the pitch of the blade (prop) and N the
    rotation
    speed (Revs) of the driving shaft. Therefore for given revs of the motor a coarser pitch will result in more speed. Conversely finer pitch = less speed. Which is why I suggested perhaps a 'scale' prop with finer pitch. Of course the above refers to motion through a solid. Ya gotta start somewhere๐Ÿ˜‰ I can provide the maths for extrapolation to slip (slip ratio) in a fluid medium ..... if anyone's really interested ๐Ÿ˜‰
    2 years ago by RNinMunich
    Response
    MV TEAKWOOD
    PS: Trouble with so called 'Smart' phones is that they sometimes outsmart themselves and us!๐Ÿ˜ฒ if you had 'Auto
    rotation
    ' ON then the pics will ALWAYS look right on the phone, no matter which way up you happen to be holding it! ๐Ÿ˜ Whether from my Samsung phone or my Sony digital cam I always upload to my PC, check the orientation (correct if necessary using Irfan View) and then upload to the site. But then I don't like the mobile App anyway ๐Ÿ˜ก
    2 years ago by RNinMunich
    Response
    Test fit the Rudder!
    Hi, would prefer to see something like a stainless or brass washer. The nylon might pick up and tear, then metal to metal contact would occur. The washer has to take both the propeller thrust and
    rotation
    , so needs to be quite robust. I doubt thin nylon would last very long, it could also heat up and extrude under load. Rowen
    2 years ago by RHBaker
    Forum
    Props
    Hi Roy, Happy New Year ๐Ÿ˜‰ Twin screw
    rotation
    is case of 'Horses for courses'! It's a Black Art and much depends on the hull shape, especially at the stern and the orientation of the rudders to the shaft lines. What you write is correct for slow, short fat displacement hulls, like tugs and rig supply ships etc needing good slow speed manoeuvrability. Especially those with one rudder per shaft. For long thin hulls (naval ships) and deep V and planing hulls (Fast launches and power boats etc) inboard turning screws are preferred to concentrate the thrust behind the centreline of the hull instead of dissipating it out into the open water. it also concentrates the thrust onto the rudder when only one rudder is fitted on the centreline. Outboard turning screws tend to push the stern up and bow down. inboard turning tends to suck the stern down and raise the bow. So making planing easier. You only made one mistake in your description: "when using the props to assist a turn, i.e one prop turning clockwise and the other anti-clockwise". The props turn in opposite directions when both are running ahead, or both astern. When turning, one ahead and one astern they then both turn the same way thus producing the combined side thrust. I was advised to use inboard turning props on my H class destroyer (twin screws single rudder) by an ex RN Captain I met at the local lake here in Munich about 30 years ago! @ Chris: What type of boat / ship are you building? Cheers Doug ๐Ÿ˜Ž
    2 years ago by RNinMunich
    Forum
    Props
    Many thanks to Mark, Doug and Roy for the information on prop
    rotation
    . I will now be confidant that each prop is on the correct side of the boat, wiring the motors and connecting the ESC correctly is a task for the future to say nothing of connecting the R.C. Thanks again๐Ÿ‘
    2 years ago by ChrisG
    Forum
    Props
    This
    rotation
    question seems to pop up regularly. Probably for a model,
    rotation
    direction doesn't really matter, but one authoritative answer can be found here: http://modeltugforum.com/index.php?topic=5947.0, which quotes from the Ship Handler's Guide. To summarise the comments: Outward-turning propellers means the blades of the propellers are outward turning in the upper half of their circle of
    rotation
    , and, when viewed from astern, the propeller with the right-hand blades is on the starboard (right) side and again, when viewed from astern to drive the boat forward, it must rotate in a clockwise direction. This is the preferred arrangement on full-size ships because when using the props to assist a turn, i.e one prop pushing ahead and one pushing astern, the side thrust from the two propellers assists the turn. The attached image from www.slideshare.net may help. Roy
    2 years ago by Trillium
    Forum
    12v esc for trolling motor build
    Interesting project. Difficult to give advice on the info available. Looks like a steerable powered nozzle at the rear but what motor is it and what are the specs? An Esc does all the hard work and converts the rx pulses into usable power. I have arduinos and they can be programmed to control the power and
    rotation
    of a motor but would need additional high power Mosfets as well as other circuitry to buffer the unit from the output. If you are really into arduinos then a walk in the park but I believe an ESC would possibly be more robust and waterproof. It would be good if you were to post a build blog of your progress as the subject is certainly different to any models we have seen to-date. Good luck with the build
    2 years ago by Dave M
    Forum
    rotating radars off mast
    I have recently constructed a rotating radar mast for my 1:48 scale paddle tug "Forceful" I have used a geared 6 volt 60 RPM motor which gives a realistic scale
    rotation
    al speed. it is a little noisy but only when close up. it is driven by a direct shaft running up the centre of the mast not prototypical but gives a pleasing effect. I may rebuild this at a latter date to eliminate the noise
    2 years ago by marlina2
    Forum
    rotating radars off mast
    I have used the kits from Mr rc World he has option of motors and the controller that comes with it gives you the fine control to set the speed of
    rotation
    to what you want and powered by your receiver pack You can find him on flea bay or on the Web
    2 years ago by kmbcsecretary
    Forum
    Twin Esc/Mixer
    My pleasure๐Ÿ‘ Re motor wires; I would be more inclined to think that the red one is the positive!! You'll soon find out if you do the
    rotation
    check I mentioned in the PM! Have fun and don't blow anything up! Check twice - pay once๐Ÿ˜‰ Cheers Doug ๐Ÿ˜Ž
    2 years ago by RNinMunich
    Forum
    Twin motor control problem
    Hi Paul, yes it sails at Bury and I am continuing to try different options. There has been much head scratching at Bury over the problem and the rescue boat has been out a couple of times to rescue the boat in reverse. The Y leads have been tried as you suggested. it is easy to test the
    rotation
    direction by feeling the air flow and slowing them manually to observe them.
    2 years ago by John2
    Forum
    Twin motor control problem
    John, Before you get any more ESCs here are a two basic things to try. 1. At the water's edge (on the stand) start the motors (both). Check their
    rotation
    . Then lower the boat into the water and see what happens. Either it should continue in the forward direction or it will stop and then go into reverse. Separately 2. Plug ESC into one radio channel and plug the other into another channel. This is a test - each ESC will be totally independent. Also we don't want use the BEC. I have had problems of a similar but slightly different nature with my Fairmile D previously, except that one of the motors would just stop after 15 or 20 seconds. Now I have each ESC running off a separate channel on the radio and the two channels are mixed so there is a master and slave channel and I use the single throttle stick to operate it. it works fine.
    2 years ago by reilly4
    Blog
    Question- Prop rotatio direction?
    Can anyone advise me on correct prop
    rotation
    direction. I will be using 2x45mm props 1 clockwise and 1 counter-clockwise. My thought is looking at the props from the rear the lefthand side will rotate clockwise and oposite for the righthand side. Please advise me if I am wrong!
    2 years ago by Skydive130
    Forum
    Twin motor control problem
    Hi Berty, the props and direction of
    rotation
    are correct. The motors only rotate in one direction when in the water. They are fine on the bench. John,
    2 years ago by John2
    Forum
    Blown esc........ again ๐Ÿ˜ข
    What ESC were you using? My experience with 600 motors is that they are power hungry, smell a lot and get very, very hot. I had two in a Slipway Trent (they advise the ECO version, no longer available) and used to be able to smell them from the shore! Could be the ESC internals circuitry shut down and may start working again when cool. Any weed in your pond will definitely overload them, which was my problem. Too big a prop will also cause overheating. I had 40mm 3 blade brass props in the Trent. It's possible that the motor is to blame if it has cooked the coils and caused an internal short. Try running direct from the battery with an ammeter in circuit. I am assuming you have checked your propshaft for free
    rotation
    and no binding, locknuts can and do come adrift and can tighten up on the shaft, which may explain the slowing down you experienced. Please keep us posted with your progress Cheers Dave
    2 years ago by Dave M
    Forum
    propshafts
    Hi Roy, to dispel any possible confusion; by 'double jointed' I mean the true Cardan link. Which is in 3 parts connected by 2 UJs. invented by an italian mathematician and engineer several centuries ago to transfer
    rotation
    from one axial shaft line / level to a different (within reason) line without using gears. They inevitably create more friction by applying more side pressure to both input and output shafts, thus more wear on the motor output bearing and the tube input bearing ๐Ÿค” Plus friction and rattling/grinding generated in two 'out of line' UJs. If, as they should be, your motor and prop shaft are in (near) perfect alignment you don't need a Cardan! My maxim is 'less flexibility - more alignment' ๐Ÿ˜‰ I like the coupling in the pic; called Stegkupplung in German, don't know the English for that๐Ÿ˜‰ They are flexible but not floppy and totally silent๐Ÿ‘ I once made the mistake (laziness๐Ÿค”) of using a Graupner Cardan to couple up a geared Decaperm to the shaft in my Sea Scout. Never ever again ๐Ÿ˜ก After the first trials I took it apart and modded the motor mount properly. The original motor (perfectly fitted by my Dad) was a Taycol Target - the one I have recently modded for controllable forward and reverse. That will now be used in an ancient Billing Fish cutter inherited from an Aunt. Cheers Doug ๐Ÿ˜Ž
    2 years ago by RNinMunich
    Forum
    What motor have I got?
    Good pics ๐Ÿ‘ At first look I would say two are identical, the 'mucky' one without the outer jacket (improves the magnetic field) is probably not. Even if it is the same type without the jacket it will not perform the same. Proof of the pudding will be in the testing, preferably with a Watt meter. The red dot signifies the positive terminal for normal (forward)
    rotation
    as brushed motors have a preferred direction due to the brush wear - Bedding in! Many don't like running backwards for long periods or at high speed. The fact that the mucky one has a gear fitted also hints that it may have different parameters. For a twin screw setup I would use the two with jackets and see how she runs with all trims set to neutral. I'll see if I can trace the type/serial number visible on the mucky one. Cheers Doug ๐Ÿ˜Ž
    2 years ago by RNinMunich
    Forum
    Working radar
    Hi Julian My 1:32 Trent lifeboat has a similar radar housing to your model. I made my radar casing around a very small servo with the feedback removed plus the the internal pins to allow for continuous
    rotation
    . You can remove the bottom part of the servo casing to make it even smaller. Mine sticks thro the top of the radar case and I plug the radar scanner onto the serrated drive. It worked fine but I subsequently removed the electrics and drive the motor via a voltage reducer ( I make my own based on a 317 chip) but they are cheap to buy. The real problem is the noise of the cheap gearing in the minature servos. OK on the water but very noisy if you are exhibiting inside. See pics Dave
    2 years ago by Dave M
    Forum
    Working radar
    Hi Julian, don't know exactly how much room you have under the radar mount but I still think you will need a couple of pulleys! Motor mounted out of sight underneath the mast - shaft running up the mast to pulley #1 - pulley #2 mounted at end of the boom underneath the the radar mount. Choose ratio of diameter pulley 1 to 2 according to the space available and final
    rotation
    rate (RPM) you want. Strong rubber band to connect the two pulleys. Didn't need this method for my destroyer radar cos it sat right on top of the Director Tower, but used the pulley principle for gun turret
    rotation
    to connect two turrets together! ๐Ÿ‘ One servo with extended
    rotation
    arc and two pulleys. Cheers Doug ๐Ÿ˜Ž
    2 years ago by RNinMunich
    Forum
    Wiring in a rx, an ESC and a battery (pack)
    first take a deep breath and calm down its not rocket science. Question does your ESC have a battery eliminator ? if so take away the dry batteries to use in something else. Now your nicads connect to the POWER side of the esc. make sure you have the correct polarity. The servo plug from the ESC plugs into your receiver whichever is your throttle channel. if you have a modern set then you can put it on the wrong way round with no worries since positive is the centre post. The output of the ESC connect to your motor. if its a brushed motor no need to worry about polarity for now. With your ESC there should be some setup instructions if there are none ...... Usually its connect and switch on receiver then switch transmitter on with throttle full listen for beeps then go to low throttle. Switch receiver off. When you switch on in future make sure transmitter is switched on FIRST ok having gotten this far it only remains to check the direction of
    rotation
    of the motor. Take off the prop ( saves fingers) and put a piece of masking tale around end of prop shaft. Switch on transmitter switch on receiver and try the throttle. if the motor spins in correct direction fine if not Brushed motor swap the motor leads over Brushless motor swap any 2 of the 3 motor leads over. Job done have a cuppa then decide to sort out the rudder.
    2 years ago by Haverlock
    Forum
    Counter Rotating Props
    Hi Reilly, both ships have twin rudders, one per screw, so the direction of
    rotation
    hardly matters. See also ma comment re KM 'Narvik' destroyers. Cheers ๐Ÿ˜Ž
    2 years ago by RNinMunich
    Forum
    Counter Rotating Props
    Now here's a question for the experts. I have two identical waterjets for fitting into a model; same size and same
    rotation
    for forward motion. Will I see the same effect as if I had two open water props which were the same? Roy
    3 years ago by Trillium
    Forum
    Counter Rotating Props
    Actually for ships with props on separate prop shafts it's counter rotating. Contra refers to aircraft equipped with contra-rotating propellers with
    rotation
    about the same axis in opposite directions. Contra-rotating propellers should not be confused with counter-rotating propellers on separate shafts turning in opposite directions. I was intrigued by this discussion, possibly because it reminded me of my model flying days. What would we do without Wiki! Dave
    3 years ago by Dave M
    Response
    Perkasa 49 inch
    Very tidy boat and nice Captain's POV ๐Ÿ‘ Next step cam
    rotation
    ? Limit switches or servo with travel extension ? After that telemetry with video back to base ?? Some sets have a good 5.8Gig back channel for this. I recently bought the Toshiba Sport camera, with a waterproof case, so I might try it on my 107cm 1:72 Type IIA U26 ! Plug in mount instead of the 88 on the foredeck. For rescue I have the Tug Southampton, bought RTR and modified slightly so I can at least push home. Not easy with long thin ships like my destroyer so thinking of a steel plate on the bow and a neodym magnet on the tugs winch ๐Ÿ˜Ž
    3 years ago by RNinMunich


    About This Website
    Terms of Service
    Privacy Policy
    Cookies used in this website are gluten free, wheat free and dairy free. By using this website you agree to our use of cookies. More Info