Forum

Fast attack craft

".....it seemed to generalise without mentioning the the decisive parameters involved, including cost difference!..." Um. Tricky to cover everything, in a 4 sentence comment! There seems to be a grave shortage of balanced advice in all aspects of modern life - though no shortage of advice per se at all! In a field where technological change is proceeding it is even harder to gather a useful view. Comparisons which were true one year are incorrect the next, and I suggest that it would be very useful to update any advice on the board which covers batteries.... Luckily there is one reasonably independent place we can go for a balanced view - the market. Although it is not perfectly unbiased, we can deduce that if some battery technologies are surviving in that marketplace there must be a demand for them, and hence that these technologies are likely to be the best available ones for some specific task. We only need to determine what that is. As a quick example, if you look at a major UK battery supplier to the model hobby - Component Shop - you will find available: NiMH - both standard and low self-discharge LiPo LiFe Lead Acid (sealed) Alkaline (probably Manganese) Silver Oxide All of these will be the 'best choice' for some application. Our interest is probably mainly with the first four. There are many battery features to take into account. The energy capacity that the battery contains is one common figure, usually measured in amp-hours, but most people do not realise that that is only correct for a particular delivery rate. To make a motor go fast you need a battery with a high current delivery rate - able to put out a lot of amps over a short time. Dry batteries, for instance, do not usually have a high delivery rate - hence the poor performance available to us in the 1960s! My top-of-my-head generalisations are below, though I am sure exceptions can be found in all cases! 'Robust' refers to a mix of physical strength and resistance to misuse, such as over-charging or excessive drain. I will try to use the words 'capacity' for the amount of energy stored in a battery, and 'delivery' for the maximum rate at which that energy can be released... SLA Very robust. Cheapest for high amp-hour capacity at 6 and 12V. Can do high delivery as well, Very heavy. Use for displacement boats, where the ballast weight is a positive benefit. Can do heavy discharge as well, but many small SLAs are designed for emergency equipment use, and expect to support a light discharge over 10-20 hours. NiMH Fairly robust. Quite cheap for medium amp-hour delivery, and reasonable capacity. Low self-discharge costs are dropping and that technology seems to be expanding in the market, though they tend to be low amp delivery types. Some types can compete with Lipos for high amp delivery in the 30-40A range. Fairly heavy. Make sure that you buy a high-delivery type if that's what you need for motors. Low self-discharge types are good for emergency flashlights and RC transmitter/receivers... LiPo - Less robust. Best current choice for high amp delivery with low weight. Only readily-available type offering current delivery in the 100+ Amps range. Light, and available in very small sizes. More expensive than NiMH, high capacity very much more, and you need a special charger, though these can be quite cheap nowadays. You should really be using a charger optimised to your battery type anyway. Remember that each LiPo cell is 3-4V, not 1.2V... LiFE - Similar to LiPo, but more robust. Slightly lower voltage, but very flat volt delivery. Typical current delivery in the 30A range rather than 100+. More expensive than LiPo at the moment, but may displace them eventually. LiPos are essential if you are using a very high consumption motor - perhaps a racing boat? But when using such currents you usually require cooling systems and quite a specialist drive train. Brushless motors can take high currents, so LiPos are often associated with them, but you can use any battery with any motor if you want - just so long at it delivers the amps! There is no reason why you should not use brushless with SLAs, or LiPos on a low-drain application - though a LiPo may be more expensive than you need for that... NiMH are perfectly capable of making a boat plane - IF you ensure that the max amp delivery is adequate. You can, for instance, buy NiMh batteries designed for wireless phones with max output 500mA or less - these will disappoint you if you try to use them for motor power! A handy rule of thumb for estimating optimum battery discharge is to look at the capacity in Amp-hours. A low-drain battery is probably designed to put that out over 20 hours, so divide the Ah by 20 to get an estimate of optimum current draw. A high-drain battery is usually designed to output over 1 hour - so divide the Ah by 1 to get optimum amps. That's only a generality, of course, and the battery spec sheet is the definitive place to look... "...more likely that HE had shares in a LiPo company to be able to afford them back then..." When it comes to electrical equipment I do have connections. 😊 If you think LiPos were expensive in the 2000s, you should try buying NiCad pen cells in the 1960s. Probably the most unusual battery I have used was a pack of saline/manganese oxide cells from ex-RAF life s, where the battery was open to the water underneath the boat and you could speed it up by scattering salt in front of it....

5 years ago by DodgyGeezer

Forum

Sternwheel paddle boat 1 hp

I inquired as regarding the life , Doug. I am reliably informed, that hamsters are very good swimmers, and they float well, so no need for life/hamster saver.😉

5 years ago by Rookysailor

Forum

Sternwheel paddle boat 1 hp

Hi Doug, would love to answer your questions, but I don't own the boat, I just put it on the forum, because on another post, I mentioned I would try and get a photo of such. I will be seeing the owner on Sunday at the lake, so will get your questions answered I hope! I will also enquire as to his life 😐

5 years ago by Rookysailor

Forum

Sternwheel paddle boat 1 hp

Brilliant Rooky👍 Question! Is it direct drive from the wheel? If so how does the speed controller work? Heating in the wheel for faster? Servo controlled sharp stick? 😮 Freezing for slower?😁 Or vice versa? Or does he charge the battery via a generator? BTW: where is his life ? SOLAS regs don'tcha know Warrant! Cheers, Doug 😎

5 years ago by RNinMunich

Forum

Where are they?

2x too late for that Doug! Funny story, was doing an Autocad course at tech years ago with a bunch of guys, and we were having a wife similarity discussion during morning tea. It was amazing how alike all our wives/ girlfriends were! We were discussing hiding places and one guy told us, that one time he made a hundred dollars doing a small job for someone, told his wife he made twenty and gave his wife twenty saying she may as well have it ❤️❤️❤️ etc. Hid the rest in the inside pocket of an old sports he hadn't worn for 10 years, which was in the back of a cupboard, and forgot about it. Months later he needed some money and suddenly remembered the stash, went to get it and found she'd left him five dollars change. 😐 just shows ya, we're not that smart !

5 years ago by jbkiwi

Response

Re: Bow fender for Riva Ariston replica Proboat Volete

These are nice. couldn't find an exact match but I believe they are key fobs (chains) So I looked on the web and ebay at keychains, fobs and found lots of potentially useful little things, some other nice little boat fenders, life s steering wheels, etc. I am a scratch builder but this could an easy inexpensive part source for some things. I also have a proboat Volere which I like a lot. When I first got it, it ran O.K. but pushed up a big bow wave. First thing I tried was moving the battery from the middle of the boat to the back, I cut off the unnecessary parts of the servo horn and then I could put the battery easily into the stern. I bought a additional battery of the same type on ebay for a few dollars except 9.6V instead of 8.4V. That helped a lot too. Having success I changed the motor, still brushed to an 05 size for an airplane. (master airscrew ma 3560) Now she easily rises right up on plane and goes like a speed boat should.

5 years ago by Commodore-H

Forum

Where did this photo come from?

It's Wally ,stripy jersey hidden under his 😂

5 years ago by marky

Forum

Model Boat crew....

A model vehicle - car, boat or plane - looks a little odd if it seems to be operating with no driver. Aircraft have quite a selection of different scale 'head and shoulders' figures - road vehicles seem to be made to standard scales so that driver figures are readily available - but boats are often made to a wide variety of scales and then need scale figures which are not readily available, and can be very pricey when they are! I was asked recently about figures on the boats I make, which are continuations of the Keil Kraft EeZeBilt line. These were originally 'pocket-money' starter kits for young children, so they were very cheap, and the fittings were not bought, but made from available household items like paper-clips. I have continued that tradition, so making an EeZebilt remains cheap and encourages manual dexterity rather than a large wallet! Figures can be made cheaply by adding filler to a wire armature, but this does require a bit of carving skill. It is easier to start with a basic shape and alter it a bit, and the obvious place to start is with a model railway figure. Cheap Chinese copies of products like the Preiser range are available on Ebay for around 10p per figure - see the link below for example. These figures are available in many scales from 1:200 up to about 1:24. The first point to make is that choosing a suitable scale to build your boat to will make it a lot easier to populate it with figures! I typically look to make boats at 1:24 or 1:48, two common scales for railways. Now the only problem is that the typical figures for sale are not sailors or naval personnel. Instead they are usually civilians, railway staff or workmen. But that is easily solved by using a modelling knife. I have illustrated this below with a set of drawings for a 1:48 figure - see the PDF link below: 1 - a typical figure. Note the and tie lines embossed on the body. I wanted to make an Indian Naval Officer, so my first step was to look up the colouring and shape of their uniform. I find that they wear white, with either a plain-front tunic or shirt and shorts. 2 - To make a plain-front, simply scrape away the clothes lines embossed on the figure's trunk. You may also need to cut any hanging parts of a away, or fill a hole with some modelling putty. 3 - To adjust arms, slice them off and then re-attach with Plastic Weld. The plastic will melt and conform to the new shape. 3 - To make shorts, just trim the long trousers in a bit at the shorts hem, then carve the lower leg to show the bulge of a calf. 4 - An officers cap is easy to make. Stamp out two tiny paper disks using a sharpened brass tube, and cut one disk in half. Cut a slot across the figure's forehead, and superglue the half-disk in there to be the cap peak. The full disk goes on top of the figures head, and the excess glue is drawn by surface tension to make a brim. The glue will soak through the paper and make it hard. See the PDF below for details...

5 years ago by DodgyGeezer

Response

Motor, mount & prop-shaft.

How does an outrunner fare with heat when closed in? The one you are using is goint to be even more closed in as it has a box built round it. I have been reluctant with an outrunner in a hull for this reason. I have a Miss Geico with an inrunner which is fine as it has a water .

5 years ago by BOATSHED

Blog

Vintage Model Works 46'' RAF Crash Tender

Here's the history bit so pay attention... Many years ago as a boy in the fifth year of my north London secondary school, circa 1971, our woodwork class was given the option to make something of our own choice. Having mastered the majority of joints, wood turning, finishing techniques and the making of table lamps, stools and bookshelves etc. this seemed a good idea, so myself and a fellow classmate and model making chum asked if we could construct a model boat. The teacher, on hearing that it was to be from a kit and not from scratch was a little surprised but agreed. So my friend and I jointly invested about 20 quid in an Aerokits 34.5 inch RAF Crash Tender from Blunts' model shop in Mill Hill (long since gone like many others) and we set about construction during lesson time and sometimes at break times. I recall we used "Cascamite" to glue it all together on the advice of the woodwork teacher because neither 'Scotch' glue nor PVA was suited to marine construction. Good progress was made over the course of our last year at school but it was never fully completed, only requiring painting, running gear and detailing. My friend decided that he needed to withdraw from the project as he was enrolling in a college away from home to study for a career in the merchant navy and I agreed to buy out his share and continue with the project. And so it was that I carried on with the painting and installing the running gear which consisted of a 1.5 cc marine diesel engine, water pickup, prop shaft and rudder and a MacGregor radio system with a stick for steering and a single button for speed control. The engine and radio came from Michael's Models in Finchley (also long gone) for £20 as my elder brother, who had started a Saturday job there, was able to get a staff discount for me. The diesel engine was noisy and smelly and a pig to start with a leather thong around the flywheel and I decided to abandon this means of propulsion (I foolishly ran it for slightly too long 'dry' and melted the soldering around the brass water !). By now I had graduated from my part time job in Woolies to an engineering apprentice with Post Office Telephones and my new income of 20 quid per week could support my modelling and electronics hobbies after my contribution to the household for my keep. So off to the model shop to buy a Taycol Supermarine electric motor, two 12v volt lead acid batteries and a suitable charger. The diesel came out and was sold on Exchange & Mart and the mount and coupling re-made to accommodate the new Taycol motor. What an improvement that was! I can't remember now what speed controller or servo I used but whatever it was did the job, and it went like the clappers on Friary Park boating lake (also long since gone) even though the radio control system was a bit crude with the non-proportional steering and 'blip' throttle control. The boating took a back seat when I acquired my driving licence and my first car (a rusty old Cortina Mk 1) and I also got involved in sound recording for radio. I decided to sell the boat and bits for £60 through Exchange & Mart and bought an Akai 4000DS tape recorder and a 'Chilton' audio mixer, built a home studio and along with a good mate of mine started making radio commercials for the new commercial radio stations including London's Capital Radio. We even won a 'Campaign' advertising award for one of our efforts! And so after several years as a 'phone engineer I moved into professional recording for A/V and broadcast and then into TV production. Fast forward to today. Semi-retired with grand kids and with more free time on my hands I still had an interest in model making so in Jan 2016 went to the Model Engineer exhibition at nearby 'Ally Pally'. It was there that I saw an RAF crash tender just like the one I built all those years ago and got into conversation with the chap on the stand. This re-ignited my model making interests and I researched the hobby and that model in particular.

8 years ago by robbob

Directory

(Other) Vosper

I always liked the sound of a fourstroke engine so I thought I would replace the brushless motor in this boat with an aircraft Os 40fs which I converted with a water cooling that I turned up on my lathe. I also made a reverse gearbox with a clutch, the gearbox is operated by a servo and works well, I also fitted a water pump so could still cool the engine while ticking over stationary, boat has been weathered and is fitted with lights and a searchlight that swivels around operated by another servo, there is also a cooling fan above the engine just to help keep things cool. (Motor: Os 40 fourstroke) (10/10)

6 years ago by Biscuit

Response

20th Scale ELCO 80ft PT boat part 9

I would check out the water cooled back plates for the out- runners as they will possibly run real hot if at all loaded up without cooling, unless you have fans like aircraft propellers (even then and in open air they still get hot!) I would look at this seriously to avoid cooking your motors. Hobby King usually has various cooling parts, or EBay, Aliexpress, Banggood etc. Bit late now I suppose, but water cooled in-runners (around 2000kv 28mm diam) are a better idea for boats. You can buy in-runners and water s to fit them as I did but they need flushing after use with CRC or similar to avoid rust, (I'll be copper tube wrapping the next lot, then there are no worries)

6 years ago by jbkiwi

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 s) 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.

6 years ago by jbkiwi

Forum

EarlyVosper M.T.B by Simplas

Hi Onetenor Fuji 15 was a good glow engine which I don't think it is manufactured any more. Aero version max B.H.P was just below .40 when tested. if it was in a model aircraft it would have been around .20 to .25 depending on prop size which was good then for a small capacity glowplug . Marine versions when on the water put out a little less and the water cooled was never as efficient as the finned cylinder of the aero version. My two Aerokits boats, the Sea Commander and the Crash Tender are powered by single Speed 600 motors running on either 8.4 or 9.6 volt Ni Mh batteries. Performance is equal to that of marine diesel power such as the 2.46 Ed Racer and D.C 2.46 Rapier, the latter I used to watch in the fast steering events in the early 1960s at Fleetwood and Coronation Park in Crosby just outside Liverpool. Taycol powered versions would be obviously slower due to the additional weight were far more reliable and you did not have to put up with injuries from excessive use of a starting cord with kids watching and "extracting the urine" shouting "why wont it go mister". Boaty

6 years ago by boaty

Forum

Elaine motor update/assembly pictures

Ah, now it's clean, it's easier to see. A Mills 1.3 Mk 2. A very good and much sought after engine. Much copied too! The water is clearly an amateur jobbie. Not sure if Mills made a flywheel for marine use. Possibly for use on small tethered hydros and cars. The engine is worth more than all the rest of the boat put together! Nice job on the clean up. You could repair those mounting lugs with some of that aluminium solder I referred to recently. Cheers, Martin

6 years ago by Westquay

Forum

ELAINE, MOTOR CLEAN UP.

Well here it is, 10.35mm bore with 16.19mm stroke. The flywheel is 41mm dia and 12.5mm thick weighing in at 117gms. As you can see from the pictures it was a pain to strip, but as I was desoldering the water the head came loose, so I unscrewed it. Then carefully stripped the rest and cleaned each piece, finally returned to the water , I had to remove the outer sleeve then cut the screws to remove the top and bottom discs. Next I removed all the crap that was stuck in the fins and cleaned the cylinder head . Finally re-assembled. All that work and still don't have any idea of the maker. There is a number on one of the mounting webs 685, on the other side is a number 2. But the Web is broken. The flywheel has RMA stamped on it and a letter J above it. So mateys what's the verdict. And god alone knows if I am able to rebuild the water . Cheers Colin.

6 years ago by Colin H

Forum

ELAINE, MOTOR CLEAN UP.

The fins look like they haven't been touched, the home made water is basically 2 brass washers with 4 screws clamping them tight to the alloy cylinder head, then a copper wrap around soldered on with 2 pipes soldered into the wrap. The fins were full of baked sludge, but luckily cleaned up with a fine needle and small swede brush. Cheers Colin.

6 years ago by Colin H

Forum

ELAINE, MOTOR CLEAN UP.

Hugely long stroke, Colin and I've never seen such a long piston. I am truly astonished that you got even a fart out of it, much less a run. I'm assuming it was built as a marine engine or would you say the finned barrel of an aero engine has been turned down to fit the water ? A very large shouldered top to the crankcase. it really is a mystery. I can only suggest home made. Martin Edited to say it's 1.36 cc., so a bit of a nipper.

6 years ago by Westquay

Forum

Launch ELAINE,

Picked this up from local antique shop, the shop owner said it was from a house clearance and made in the 1940's. It needs a lot of work to be done to bring it back to life, look at the photos and see if any of you can help, as I haven't seen any control system like it. I think the motor is a modified plane engine but the water will have to be destroyed to find out. So any thoughts on the challenge ahead would be good to hear. Cheers Colin.

6 years ago by Colin H

Forum

Launch ELAINE,

Thought U were goin' to hit the hay a while ago John!? 😉 Greetings from one model fan and insomniac to another👍 BTW agree with your comments about the water . Sweat the screws out and the rest should be relatively easy. "In this the most perfect of all possible worlds"! Cheers All, Doug 😎 BTW: TELL me about those relays! For a year or so back in the early 70s I used to service and calibrate the radiation monitors at various nuclear research / power generation sites around England. The detectors tripped a relay via appropriate drivers, which then triggered the unit Nixie tube, etc, etc. My job was mainly cleaning and setting the relays and doing a calibration against 'normal' background count, cosmic radiation etc. To reassure folks; during the whole year - year and a half I never ever saw a count above background! But then - that was 46 years ago 😲

6 years ago by RNinMunich

Forum

Launch ELAINE,

Thanks Doug, have just had a scout round the Web, from what I can see on my engine it's more likely to be a Mills. But without removing the water and exhaust covers I've no idea. Cheers Colin.

6 years ago by Colin H

Forum

Launch ELAINE,

Colin, it could be that the is just that, a coat, a covering that allows some water to take conductive heat away. One hopes that it isn't allowing water to touch the actual motor or grot will be your future! The way the is made may give you an idea of how it operates and how best to get it apart. As it's copper, it'll only be soft soldered I would think judging by a lot of grey clag around! Worth doing though since clearly it's a runner, despite all the muck on it. But I would invest in some proper model diesel fuel, if you can justify the cost! Then you shouldn't get those 4" flames out of the stubs! Cheers, Martin

6 years ago by Westquay

Forum

Launch ELAINE,

Well Martin, whoever built the water didn't think it was necessary to be able to strip the motor, but I've been thinking about it and have decided to try and get the off so that I can resurrect the poor wee beast, at least I'll know what engine it is. Usually the tick over was set at about 1500revs and the peek was about 2700/3000. I think that would be a tad too quick for a boat the prop would be cavitating at that speed. The boat is only 27 1/2" LOA with an 8"beam. Cheers Colin.

6 years ago by Colin H

Forum

Launch ELAINE,

Fantastic stuff, Colin. if you can get that ancient engine to run on diesel from your car plus Methanol, you could get that kitchen nozzle going! Where did you just get some methanol from? I'd say the engine is something like an old ED Competition Special or similar with a very home made water and even more home made exhaust wrapper, requiring tubes to be added to the 2 stubs and led to the stern or either side. Doug's yer man for anything lecktrickal. is there actually anything of the original RC in there apart from that superb kitchen nozzle affair, which deserves to be preserved all on it's own. Control will have been vestigial at best as the engine has no throttle and the nozzle arrangement will not have had any level of proportionality to it. it will, at best, have been push the button and see where the boat ended up, knowing it could, at a a pinch, be brought back to where it started. At one time all RC was like that. My own REP set was left,centre, right, centre, etc. A wonderful throwback that must be preserved. I wish my local junk shops had stuff like that! Cheers, Martin

6 years ago by Westquay

Forum

What is the optimum prop shaft angle?

This is a Norstar Kingfisher design. I want to place the motor beneath the rear hatch where the batteries sat. The CG was far to forward and this is a heavy model so it never ran very well. the motors ran hot even with a water . I am moving the motor back, using a shortened prop shaft ,but what shaft angle will produce the optimum performance? Ron

6 years ago by Ronald

Blog

Painted outside

Finish painting and adding some stickers, and a couple of pictures of the real thing. Fitted Motor in a water cooled and motor mount. The motor is a 3650 and is rated as 3060kv Max Power: 1300W Max Voltage: 19V Max Amps: 68A Shaft Diameter: 3.2mm Shaft Length: 15mm Connector: 5.0mm Banana Connector Net Weight: 181g Servo fitted sideways via rubber bellows to external rudder fixed to transom.

6 years ago by CB90

Forum

Brushless motor selection

MY #1 CHOICE WOULD BE A NEU MOTOR . NEU MOTORS ARE A BIT COSTLY BUT HOLD A LOT OF RECORDS . LEOPARD MOTORS ARE NICE TOO .BOTH MOTORS HAVE WATER S FOR THEM . I PUT A NEW 1515 IN A 27" CATAMARAN RUNNING 4S AND GOT 68 MPH ON THE GPS. ALSO I HAVE AN OLD DUMAS SKI DADDLE 36" RUNNING A LEOPARD LBP3674 - 2650KV WITH 3S AND GET ABOUT 40 MPH . I AM NOW WORKING ON A 36" GENISIS CAT WITH TWO LEOPARDS . PERFORMANCE TO BE SEEN !!!! I HOPE THIS HELPS YOU OUT SOME .

6 years ago by ARTH

Blog

Paint job

Installed hardware used brushless 2860 4050kv motor with water-cooled mount and , kept prop-shaft at a low angle. It drives really well to the extent that its too good to race so I have started again with another boat for racing.

6 years ago by CB90

Forum

It's a sad day!.

Yep, built mine with my Dad, a 34" Crash Tender. We used the then new PVA glue and to be honest, 54 years later it still holds well and is waterproof. I really must finish it some day! I confess I never had an IC engine in a boat, but I've always had an ED Racer with water and big brass flywheel. Still have it on my shelf with others, but I could never get the buggers to start! So Dad made sure the Crash Tender had a good electric motor when he spoiled me with it all for my 11th Christmas. I had REP single channel R/C and a Taycol Supermarine motor and Taycol coupling. That's what's in it and will stay in it. Alas the R/C gear was stolen. I could replicate the case, but there just ain't the time for all these things, so an old Mini Hex 1970s Propo set will go in it as a classic curio. I used it for years with the REP on the oyster ponds at Paglesham. Left, centre, right, centre, wiggle right, wiggle right and so on. The Taycol ate batteries! Martin

6 years ago by Westquay

Forum

It's a sad day!.

If you see on my list above after the engine size if a D was noted its diesel and all these engines were for boat use and water cooled. However my father did make any parts needed so conversion to water cooling on an engine was no problem if needed. Stephen.

6 years ago by Novagsi0

Blog

H.M.S. BRAVE BORDERER

From the brief pool test, had decided that the motors could be susceptible to overheating, so connected up the water cooling system and powered it with a small pump. Did not leave enough space to fit a scoop behind a propeller anyway, but prefer the positive action of a pump though. From feeling the ESCs, was also concerned they could overheat within a confined space such as the hull. Mounted a couple of small fans in a bridge structure above the ESCs, along with the ESC switches. Not sure either of these cooling modifications are really required, but erred on the side of caution. Final weight of the hull, with all electrics (apart from battery) comes to 5.05 lbs. Looks like will not achieve the target weight of 6 lbs, but am hopeful will be able to get close to it.. Built the deck up with gun mount bases and a removable decking over the engine area. This limits access to the internals; so will not fit it permanently until the test program is complete and all modifications incorporated. Have now reached a point where any further work will be to start finishing the model, unless drivetrain modifications are required. Have thus decided to leave it until after the first open water test date. This will be in late May as am away until then.

6 years ago by Rowen

Response

H.M.S. BRAVE BORDERER

Thanks for your advice. Guess am stuck with the water style now, will see how they work. Was intrigued by these rubber ones though, they have an internal scroll which defines the water path. Rather like a coil. Intend to make the small ESC wire mods you and Doug recommend. Thanks

6 years ago by Rowen

Response

H.M.S. BRAVE BORDERER

Hi Rowen, I have had water cooling on all my patrol boats running at 12Volts, whether brushed or now brushless. For the brushed motors I have used aluminium tube coils with water pickups between the propellers and rudders. I did try water s a couple of times but found too much friction loss and therefore lack of flow. For the newer brushless outrunners I use a brass tube soldered to a brass plate across the front of the motor fitted between it and motor mounting bracket. I agree with Doug with regards to the disconnection of the red wires on the ESC's. This is now common practice, especially if you have an external receiver battery.

6 years ago by reilly4

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H.M.S. BRAVE BORDERER

Once the rudder, propeller and shafts were installed, the position of the motors could be established. A light aluminium bracket to hold all three was fabricated and bonded to the hull. Due to the high speed capability of the brushless motors, particular attention was paid to alignment. Also kept to the shortest prop. shafts that could be fitted to avoid whipping. Although the motor type might change, whatever is best will require a sound electrical installation as the current requirements for each brushless motor could reach 50 Amps. Wired each motor and ESC separately with its own dedicated fuse to give the maximum system protection. There is an extra fuse section allocated for auxiliary circuits, such as a cooling water pump and lights. Will try the original planned layout of 3 x 2835 motors with 30mm propellers and a 2S Li-Po battery first. Am hoping the reduced voltage will also make these motors more tractable. For the test program the three ESCs will be each controlled from an individual Rx channel. Once the final layout is determined, a more sophisticated and flexible control system can be installed. To minimize ballast, particularly around the stern, the battery will be housed as far into the bow as possible. After the test runs the final battery type, size and location can be established. To assess performance, hope to try both 2 and 3S Li-Po batteries. Planning to reduce heat build up by fitting cooling water s to the motors, these are easiest to instal at this stage so the wiring or mounts are not disturbed in the future. Have not decided the layout for the water circuit yet, but this easily can be added later. All that is needed now is the ice to melt off our local lakes so tests can commence.

6 years ago by Rowen

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(Racing Boat) Interceptor

Zoom 1 (Interceptor) Mono boat. Built from a Glassfibre hull, brought on Ebay for £35 the hull is a slim mono racing type with a self-righting side cabin it runs a 1400W 14V 2958 4200KV Brushless Motor and 29-S Water Cooling with additional air cooling fan. I did not want to use a flexi drive as high maintenance and prone to failure so the shaft runs via two universal joint one at each end. the propeller is a 38mm copper alloy The ESC is a 200A and water cooled the twin rudders supply separate water one for the motor and one for the ESC. The rudder are positioned to reduce prop-walk and are hinged to prevent damage if hit a object in the water and ride adjustment. Turn fins and trim tabs for ride adjustment were provided by a spares kit for another boat. also foamed and added an inner sealed hatch, a rubber bump strip and safety loop. The Boat is fast and over-powered used at half throttle, may use a 7.4v lipo instead, the self righting works well. 20th April 2018 while running on 11.1v the boat stopped, no response on retrieval it was found that the manufacturers battery connector had melted and the connection lost see later pictures. the battery was made by FLOUREON and was a 35C with 5500mah capacity the 80A fuse had not blown. (Motor: 2958 watercooled) (ESC: Unknown 200A) (8/10)

6 years ago by CB90

Forum

Motor problem

Fair enough pmdevlin I accept what you are saying, however it started as a motor not being big enough for the size of the propeller and then went on further as the shaft was 4BA not 4mm and I could not locate a smaller prop, a plain brass tube and stainless shaft has been fitted,way back in the 60's when it was first started and as I knew nothing about boats in 2015 when I finished the basic structure, I did not know that it would have been the smart thing to fit a shaft with bearings. So this is the way I am going to go, I have ordered the 850 brush motor and the adapter to fit the motor shaft to my red coupling,this I have been assured will be more than big enough to drive the prop without getting hot or needing a water , if this is the case when I fit it and sail it, then result, if not I will then have to go down the path that you suggest, I have nothing to lose trying the larger motor and everything to gain if it works. By the way the batteries are all new

7 years ago by RichardSReade

Forum

Motor problem

I looked at the Cornwall model site and saw that, what i have decided to do is to leave the two Ni cad batteries in situ and I have weighed the rear/mid section lead weight and it is just 56 grams heavier than the 12 volt 7 amp/h lead acid alarm battery so I will use the 12 volt battery and ditch the lead, the weight of the boat will be the same, I also trimmed the lead at the front end so the bow will come up a fraction more. I have taken the prop of and measured it to be a 55mm, so I am going to fit the water intake, hopefully with some advice from the forum "techys"as to the position, in the photos this is where I can fit it so it is out of the way of the rudder and prop.what do you reckon, I can then get a suitable motor with a water which will be happy to run on 12 volt with enough power not to get hot turning a 45 to 50 mm two blade "x" prop, as suggested by pmdevlin, I may get the Lloydsman up and running as all that needs is dusting of and batteries charging up, (two 12 volt 7amp/h in parallel) and the receiver from the commander fitted although I have not floated it I bought it as a complete working model in 2015, so it is about time it came out of dry dock, also I can look to repairing the rigging and finishing the Odessy Yacht I bought at the same time as the Llyodsman also in dry dock.

7 years ago by RichardSReade

Forum

Motor problem

Thank you gents, I will get a bigger motor and reduce the prop size as I do not want it any faster than it is, also a smaller prop as everyone has said will reduce the power drained from the battery, I have a water scoop and tubing so will be fitting that today and will fit a water around the motor, also I am thinking weighing the lead weight fitted in the compartment behind the motor and replace some or all of it and fit a 12 volt 7 amph sealed lead acid battery, presumably this will last longer than the present batteries fitted, or will it?

7 years ago by RichardSReade

Forum

Unbekannte Flitze. A very flighty girl

Allen and Doug I see that you both do not sail with or belong to a model boat sailing club so are sailing mainly on your own. Most model boat clubs will have completed a risk assessment and produced guidance and club rules to protect both the members and public. if the waters are Council owned this can be quite a task and can result in permission being removed if not followed. Waters are not easily found and can be lost because of the actions of one individual. Whilst I can sympathise with the desire to recover a sinking/stopped or sunken model there are ways to do this safely. We have an RC rescue boat but I have also used long poles and fishing rods with lines. We also have waders to allow recovery from near the bank under trees etc as well as a boat and life s, if necessary, but not I suggest without having help on shore in case of difficulties. You are of course entitled to risk your own life but this is a hobby for me and I suspect many of our members and I prefer to avoid unnecessary life threatening risks. Dave

7 years ago by Dave M

Response

Red Cat hydroplane

Hi. The HK controller is an Aquastar 120Amp water cooled which has suffered all of the burn outs and never failed. SKU: 9052000008. The failed motors were all 2848SL 3900kv Brushless inrunner (WaterCooled) SKU:3900-2848SL. I have my doubts about the specifications as their watts and amps do not add up. I have a temperature sensor on the motor sending info back to the TX and usually after a full charge and a fast run it would get to 60°C, then I would cool it to 45°C before the next run it burnt out at 85°C when I wasn't paying attention. The new motor runs at about 45°C how ever hard it is pushed. Still using the 120A ESC. The new motor was in the HK sale and I don't think they do it now SKU:S2858-2630. it just happend that the water for the failed unit fits it.

7 years ago by SimpleSailor

Forum

3d printing

Here's another I prepared earlier, I found the file for it on Thingiverse, unfortunately the file made a boat 300mm long, so I printed all the parts at 200% size👍 I've got all the running gear for it now except for the water for the brushless motor, come on China, get your finger out! Cheers Wayne

7 years ago by Midlife306

Forum

Battery problems

Hi Allan If you had water cooling and it was provided by your pump then it would seem the prop was far to coarse a pitch for you fast motor and very powerful battery which was quite capable of delivering well over 200 amps through the 160 amp ESC. Your comment re the power delivered rather confirms this, and holding a model at full speed to test is only possible for about 5-10 secs max. You need to get a much smaller and less coarse pitch 3 blade prop plus a wattmeter to measure the current to make sure you are no where near the max ESC current. Personal experience suggests this should be less than half the rated Max so say 70 amps for your ESC. Testing should be brief and stopped immediately if the current being taken is above 20-30 amps. Smaller props will reduce the current to an acceptable level and your model will go faster and for longer. As a guide 14 volts at 70 amps will be using 980 watts so you will perhaps appreciate why cooling is necessary. Also at such high currents the wiring from battery to ESC then motor will need to be capable of carrying such high currents. As there are three wires to the motor and the power is pulsed at high frequency they are usually not as heavy as the battery to ESC. Your battery to ESC connectors also need to be capable of high current such as Deans, Euro or bullet type. Having looked on U-tube it does appear that others have had similar experiences with this ESC. The specs say it is capable of running at 14.4 volts so when you buy a replacement I would ask your local store to run your motor with the ESC and your battery to ensure it works OK. if they have a wattmeter ask them to test the open current then also buy the wattmeter and a smaller 3 blade prop of slightly less diameter than that of the motor without the water . Do a final brief test at home holding the model and see briefly what the wattmeter reads, this will be near the max current draw. if it's too high you need a smaller prop. There are several Perkassa builds on the site and some use brushless with success. if you search you will find details of their power train which may help you choose the best set up. I do hope you will soon have your model speeding round your lake. Dave

7 years ago by Dave M

Forum

Battery problems

PS Allan, there are several water s / spiral tubing available for cooling brushed motors, try Hobby King, or just get some alu and silicon tubing and make your own. Apply some heat conducting paste between the or tubing and the motor casing (as used in the electronics industry for mounting power transistors, processor chips etc) available in tubes also in model shop site for a few dollars. Good luck

7 years ago by RNinMunich

Forum

Battery problems

Hi Allan Was the boat in the water or on the bench? There are several posts online indicating that you cannot run this ESC without water cooling. You did say you needed a separate water cool motor. is it possible the motor or ESC water s were blocked? Hope you can find a solution Dave

7 years ago by Dave M

Forum

King-Fisher changes made

Hi Robert, I saw that post when researching this boat, it helped me decide how to continue building the kit. if I do not want to use a water- style motor, is there a motor you would recommend. I have several battery packs; One pack is a 4200 - 7.2 v NIMH The other are two packs both being 2400 - 7.2 NIMH these are with connectors to allow longer run time. Thanks, Ron P.S. I am relatively a new builder.

7 years ago by Ronald

Forum

Sea Rover Help

Hi Simon. The two holes are just so that I could pour some Z-Poxy in after the skins were on, helps seal every thing. The motor is a brushed motor, and I had the water , so it will be fitted, don't think it will need it though. If I ever change the brushed motor for a brushless set up the water cooling is already there. Alan

7 years ago by AlanP

Forum

Sea Rover Help

Thanks Alan, your boat looks really nice, why the 2 holes in the fore deck? I have only just started the build I will post some pictures later. I see you have a water cooling on your motor , I will be buying a new motor as the only power sources I have are sails , this is my first motor build. is it worth getting a water cooled motor . Simon.

7 years ago by simonricho

Forum

Brushless

Hi Brian I am not sure which model you are referring to but your description of period photos suggests it is from the late 1930's and yes they were not a planing hull. Does your model have one or two props? A few pics of the model would help, you can upload by clicking the yellow box to the left of this input panel. Brushless can be a bit daunting at first experience but they are not difficult to use once you are familiar. You will already have seen they have three input wires and these need to be connected to an individual Brushless ESC for each motor. Doesn't matter which wired connect to which socket on the ESC but if your prop spins the wrong way you can swop any two connections to change the directiopn. The kv rating refers to the unloaded speed of the motor for every volt you apply so for say a 1000kv motor supplied with 11.1volts the motor would spin at 11100 revs. There are two types of brushless motor "in-runners" and "out-runners". This refers to the construction used with in-runners generally being less bulky. The outrunners will produce more tork and can be more suited to slower speeds. if you need to water cool the in-runners have a fitted around the motor body whilst the out-runners use a water cooled mounting attached to the bearing. Both are suitable but I personally prefer Out-runners. For your model I suspect an inrunner may be preferable due to the restricted space available. Unlike brushed motors brushless do not like being overloaded and work best when they can achieve their max efficiency at near max revs. They have a max watt rating which should not be exceeded (Watts = Amps x Volts). The casing may be marked with numbers 42-56 which is the diameter 42mm and length 56mm. In my 48" Sea Queen I use a 42 size 850Kv water cooled motor of 700 watts and it is happy driving a Prop Shop prop of 42mm at 45 amp on full throttle. To measure your wattage you need to acquire a Wattmeter to measure the actual current draw with the model in the water. This will give an indication of the max current at max load as you hold the model stationery. If the watts are greater than the motor's rating you need to reduce the prop size/pitch. I like scale props so use 3 bladed brass and avoid using racing plastic/nylon props as they can overload the motor. The ESC should also be of a sufficient rating to handle the running current, I usually try for at least a 50% margin ie 75amps for a 50amp max current. Finally your setup must be really secure (I know from personal experience) and free running. The revs produced are possibly higher than what you may have experience before and any fault can and will escalate very quickly. At high currents the motor coils will fry in about 2 seconds should anything stall the motor and you can expect to see smoke and a ruined motor. If you post some pics we can give you more detailed help on your particular setup. Dave

8 years ago by Dave M

Forum

Speed Controller

Hi I peek the motor and speed Controller can you all tell me if its the right speed controller for the motor r not? heres the Specs:Turnigy AquaStar 4084-620KV Water Cooled Brushless Motor RPM/v: 620kv Winding: 2.5Y Max voltage: 37V (10S) Max Current: 105A Max Watts: 3050W Resistance: 0.03ohm No Load Current: 0.7A Can Diameter: 39mm (actual motor diameter) Can Diameter inc. Water : 49mm Can Length: 84mm Shaft Size: 5mm Weight: 508g Motor Connector: 4mm bullet plug and heres the Speed Controller im going for Specs: Voltage input: 2~6 LiPoly cells (6~18 NiMh) Continuous Current: 120A Burst Current: 720A BEC Type: Switching with on/off switch BEC Output: 6V@5A Motor Connectors: 4mm Servo lead: JR style Servo Lead length: 300mm Water Cooling Pipe: 3mm I/D~5.4mm O/D Dimensions: 68.5x39.4x32mm Weight: 160g many thanks cliff

8 years ago by Mataroa

Forum

Assorted R/C boats for sale from Retired model boater !

Got some IC stuff but all "aero" nothing with a water . sorry. BTW all the three boats originally listed are now sold.

8 years ago by stevewatkin