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>> Home > Tags > weight

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motor sizeing by jimdogge Petty Officer   Posted: 2 days ago
Hi chaps jim dogge here, im just about ready to fit out my wave princess with some sort of motor and bits. I have allsorts of outrunners and ESC to match aeroplanes but havent a clue as to where to start. A 1.5 diesel, whats that equivalant too is the weight thrust formula the same for boats. l would prefer to stay with out runners, the cooling aspect is no problem l did it for a living. a prop size how is that worked out for a boat.

Darby One Design hydro... by Westquay Fleet Admiral!   Posted: 2 days ago
Hi all, here's progress on the Darby One Design. Got these pics just before it started peeing down, so no Chris-Craft pics. Fitted a brushless outrunner I found in a box. Might work, might not... Home made prop shaft/tube, home made off-set rudder. Planked balsa top cover to keep weight down. 1/6th scale 26"long, 10" beam. Thick grey cellulose primer to act as a light filler for scratches, etc. Martin

Nomenclature... by RNinMunich Fleet Admiral!   Posted: 2 days ago
Hi John, think somehow you've got the wrong end of the stick!🤔 All BECs are Battery Eliminator Circuits of one sort or another. The objective is to eliminate the separate receiver battery, sometimes necessary purely to save weight and/or space in small models. If you do that then the RX power must come from the main drive battery, which then has to supply all RX functions; servos, switched lights etc etc. Personally, if the boat / ship can carry it, I prefer to use drive batteries for just that and use separate battery for the RX and special functions. Some of which, like smokers for instance can be current gobblers. Cheers, Doug 😎 PS If you ever find a way of eliminating all batteries and still get the RX to work and the boat to move PATENT IT QUICK!! 😁 Cheers, Doug 😎 Hmmm! Maybe a raft towed behind with an array of hi-current solar panels!? 😁😁 Years ago in my work in NAVAL COMMS systems I once suggested to a shipbuilder, who was complaining about the number of antennas needed, to put some of them on a raft behind the ship 😉 Now they are doing just that with antenna buoys from submerged submarines! No credits 🤔 ... SIGH 😉

Elke HF 408 by Neil-S Seaman   Posted: 2 days ago
[Score: 5/10] 20"/600g Elke HF 408 Capable of 2mph Single Propellor (3 Blade) Direct Drive to a 6v (3 Blade) Powered by NiMH (7.2v) Batteries - Comments: This is a restoration project - my first radio control boat 'Elke', is a small fishing boat with plastic hull, a Graupner kit, purchased in Germany when I was serving in the Army there in 1974. I am restoring it for my grandson. It used to be a good runner with a 6v battery, small electric motor, two servos, one wired so it could move boat in reverse as well as forward. A good little sailor, light in weight and a good pond model. Had to be careful of wave height. Anyway, it has been in the garage for 40 years now so much to do. The inside is a bit of a mess and everything has a layer of dust. I will fit a speed controller and NiMH battery. But nothing too difficult so hope to have it finished for Christmas.

"Maureen Lee" by Ishmael Petty Officer   Posted: 3 days ago
[Score: 8/10] 33"/3700g "Maureen Lee" Capable of 3mph and a runtime of 90mins Single Propellor (3 Blade 30mm) Direct Drive to a 550 type (3 Blade) Powered by NiMH (7.2v) 3Amp/h Batteries Controlled Through Unknown ESC - Comments: The “Maureen Lee” started out as a Bristol Bay ready-to-run semi-scale model of a typical European fishing cutter. Many modifications were made to her to make her look like an old, worn-out fishing boat. Factory-installed switchable work and navigation lighting means that she can even be operated at night. A 550-size electric motor and metal propeller allow for ample power. A Bristol Bay model is supplied practically fully assembled… you need only mount the two masts and install the batteries. Numerous robust details make this model look great at home or on the water! Technical specifications: Hull length: 850 mm Width: 220 mm Overall height: 737 mm Total weight: 3650 g

HMS BRAVE BORDERER by RHBaker Fleet Admiral!   Posted: 3 days ago
Adjusted the transom flaps and reprogrammed the ESCs to the softest start settings, retested. Until now, the test runs did not have the duration or stability to really examine what was happening. Using 3 S batteries acceleration is rapid and a is plane quickly achieved. However, as the acceleration continues and speed increases, the bow digs in. A cloud of spray then surrounds the model as the plane is lost. Brushless motors do not modulate as smoothly as brushed and adjusting power tends to be erratic or exaggerated. This is a scale model and the propeller shaft angles are per the plans. The thrust from the propeller has two components, horizontal and vertical. The horizontal propels the vessel forward. However, the vertical component forces the stern upwards and, correspondingly, the bow down. Have moved as much weight as possible towards the stern to counteract this, limited by maintaining the correct displacement and waterline. The easiest solution is to reduce motor power, decreasing both speed and the lifting component. Decided to retry the 2S batteries as they give reduced power. A plane is again achieved, but as the motor response is more docile, it can be controlled. If the speed gets too high the bow lowers, as before, but the motor output can be more easily adjusted. Spent a pleasant half hour or so with the vessel accelerating onto and off a nice, controllable plane. Much less spray and drama than with 3S and much more controllable. Have now decided to revise plans and use 2S rather than 3 batteries. A further advantage is the motor noise is muted and now sounds more like a gas turbine than a dental drill! Finally feeling comfortable with the model. Will thus shelve further building until the late fall when sailing in Canada concludes. Want to enjoy the rest of my fleet in the meantime! Will summarize my experiences with brushless motors in another blog shortly for the benefits of others contemplating their use. After restarting the model will resurrect periodic build blogs to advise progress.

EarlyVosper M.T.B by Simplas by boaty Captain   Posted: 4 days ago
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 jacket was never as efficient as the finned cylinder jacket 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

EarlyVosper M.T.B by Simplas by RNinMunich Fleet Admiral!   Posted: 4 days ago
"Maybe but ballast ,is ballast,is ballast. However it's achieved." Sure John, but at least a heavy battery is useful load and not 'just' ballast.😉 Have no idea what shaft power the Fuji produces (only know their excellent 35mm film😉) but the Taycol Supermarine is rated at 22.5mHP (22.5/1000HP) at 3.5A, 4000rpm. Efficiency 52% 🤔 so you have to stick twice as much electrical power in to achieve that! Sooo, given that 1HP = 745.7 Watts - And electrically P=IxV (Current x Volts) 22.5/1000HP = (745.7*22.5)/1000 = 16.778W so ~33.55W in. Thus if I = 3.5A they must have done that test / measurement at about 9.6V. The Supermarine also runs great at 12V but maybe not with max efficiency!? With a spec weight of 2&1/2 lb i don't even want to get into Power to Weight Ratio, although I measured Colin's motor at 947gm = 2.0877776229lb 😉 But then, some of the motor had corroded away As I'm currently renovating a Supermarine for Colin H. This makes me start thinking about rigging up a test jig so I can see what it actually produces!!! Always up for a challenge 😁 Got nowt else to do 😁😁 Would be useful for other motors as well if I can get it figured out😉 Happy fiddlin' folks, cheers, Doug 😎

Life Rings by mturpin013 Fleet Admiral!   Posted: 6 days ago
The white metal fittings supplied with the kit are somewhat lacking in detail and some are overweight to say the least. I decided to produce some life rings to my specification I had tried to find suitable replacements on the web without success. So how to produce the ring part. I first tried with plywood but the finish achievable was not acceptable (can be seen in the pictures) so I then decided to use Bamboo (Ikea phone stand) for those who have followed from the start the same material as the grating on the foam tanks. First I cut some rough circles out of 10mm bamboo sheet and drilled a 10mm hole so it can be mounted on a 10mm screw mandrel. This allows the piece to machined on one side and then reversed and machined on the other side. The tool I used was ground with a 22 mm radius to produce the shape on one side of the ring and then when reversed and machined again the tool actually “parts off” the ring on the inner diameter leaving the ring free on the now remaining peg, the finish on the bamboo was good enough without any further sanding. The next step was to put a slot in the OD at 90degree intervals to hold the “rope” in position while the rope is bound in four places. The easiest way was to make a jig to hold the ring and to keep the rope in place while it’s glued into ring, it can then be removed and bound in four places each turn being super glued to keep it in place. Next job is to give a coat of sanding sealer that stiffens the rope and seals the wood. The rings are theoretically held to the cabin roof with clamp type brackets so again to ensure consistency I machined a piece with a suitable profile. I then cut radial slices to create individual brackets. The rings will actually be fastened to the cabin roof with 2 x 8BA bolts this is to enable them to be removed for painting of both the ring and the roof. At a later painting stage, I will be giving them two coats of grey primer and three coats of white, then hand painting the rope loops with red paint. The finished rings are much lighter and hopefully look more realistic.

Taycol Supemarine Resurrection by boaty Captain   Posted: 7 days ago
Interesting restoration project . Great fan of Taycols myself though its some 24 years since I had one. The motors themselves are bristling with character as you can see the armature rotating and you do get the smell of something electrical along with it. Taycols go further than being just power units as they are good ballast due to their weight. Unfortunately through progress they have been replaced by little tin cans and brushless devices. Hopefully someday a person or a company will put them back in production due to the number of retro boat kits now being sold. Boaty

Bending thin plywood by Westquay Fleet Admiral!   Posted: 7 days ago
Gardener, I go out in the garden, where I have some large ex paint tins. I soak the ply in the water butt, then wedge it against the inside of the tin with a stick of bamboo, until the sun has dried it. By then it's nicely curved and can be glued to your frame members, you made while it was drying, out of 3mm ply. Make sure the top really IS dry and then weight down the structure while the glue is setting thoroughly. I've just made a long section of deck/hatch for my Chris Craft version of a Sea Hornet that way. Cheers, Martin

BRAVE BORDERER by RHBaker Fleet Admiral!   Posted: 13 days ago
Been researching the squeal and stutter on other websites and conclude RFI is probably not the major contributor. Others attribute it to a mismatch in the ESC / motor timing, which seems more likely. Whatever caused it, resulted in the affected motor failing. Which came first, the failure causing squeal or squeal causing failure is open to conjecture. Much to my surprise the manufacturer has decided to replace the motor under warranty. In the meantime, the motors I had planned to use originally (2800kV Outrunners) came into stock, so purchased a couple. Until now have had to use the ESC default settings as did not have a programming card. This also arrived with the motors. Following advice from another contributor reprogrammed the motors with “softer” start and acceleration settings. Fitted and tried the new motors and settings. On the bench, the squeal and stutter have almost gone. The motors are also more tractable. As the brushless motors are now going to be used for high speed operation only, with slow on the centre brushed, thought could simplify the controls by putting the brushless ESCs on one control system using a “Y” lead. However, this introduced inconsistent and erratic motor responses. Reverted to the two previous separate controls, port and starboard. On the water the performance is fine, as is the reliability. The 2S battery gave almost half an hours operation. The bow lifts nicely with both 2 & 3 S Batteries; plenty of spray. Hopefully resembling a 50 knot vessel! Another adjustment is needed to the transom flaps to try to hold the bow down later as she accelerates. Feeling now to finally be making progress with this model. The squeal has not gone, nor has erratic motor operation. The squeal is high pitched screech, rather like treading on a budgie! When it happens, bringing the control back to neutral and advancing it again almost always overcomes it. The erratic operation happens also when starting and is rather like the motors are not getting a signal to react to the control. Again, returning through neutral briefly seems to correct it. The revised motors and ESCs have increased the weight to 6lbs for the hull including all running gear, excluding batteries and superstructure. Whilst still trying to control weight have concluded this figure is satisfactory as the performance certainly is.

Brooklyn Finally Completed! by RNinMunich Fleet Admiral!   Posted: 19 days ago
Evenin' Ed, When you first mentioned the weight I started thinking of a guy I'd seen with a big heavy boat slung over his shoulder! No, Not the boat itself 😲 He'd made a sling attached to the boat stand so he could hang the weight over his shoulder and just guide it with his hand. Might have to start doing something like that soon for my 5foot Destroyer, Belfast and Graf Spee models. 🤔 Like the Stones used to sing, "What a drag it is getting old"! Cheers, Doug 😎

Launch ELAINE, by RNinMunich Fleet Admiral!   Posted: 20 days ago
Hi Colin, As discussed on the phone; 2V grid bias, 90V anode supply! In those days they had 90V dry batteries, they musta run it 'sumow'! 😁 Don't give up so easy! Nowadays how about a 24S LiPo? Or even Martin's 'big box' solution. http://www.batterysupports.com/lion-lipo-nbsp-88v-nbsp-24s-c... 24V chargers / balancers won't be cheap though🤔 2V is no sweat; 2V SLA, a la Glow Plug starter. How big is the boat an' how much weight can she carry? My first car radio was an ancient Echo valve job, with an inductive inverter bolted under the dash to produce the 90-100v for the bottles. Took me ages to find a way to mount it so it didn't make the whole dash hum like a swarm of bees😲 Later there was briefly a generation of 'low voltage' valves. Soon superseded by transistors from 1948 on. (And NO I'm not pre '48 vintage, well not quite!😉) Looking forward to your progress reports. Would really love to witness one of your displays. Please keep me posted about dates. All the best to you both, Cheers, Doug 😎 PS building a transmitter to match won't be easy. A TX on the right frequency is relatively easy, the tricky bit is the 'modulation' for the control functions! Hats off to your guy 'up the road' if he manages it! I'd really really love to see THAT!

Modav Huntsman 31 by RNinMunich Fleet Admiral!   Posted: 22 days ago
Hi William, S, X35 !? No idea😲 I assume they are terms from the racing world which I have no particular interest in. My intention wasn't to make her into an offshore racer. As it is she's well over scale speed, but fun to run, and that's what counts ain' it? 😉 Gives a good long run time, 1 hour plus, using a Propdrive 2830 BL and a 3S 4Ah battery. All up weight 1974gm. LoA 24", beam 8.5". My prop is simply a 35mm ca 14 pitch from Raboesch. Actually wanted the one with a blunter hub but they weren't available when I wanted it. The pointed hub variant is actually more like as fitted to larger naval units in WW2. Sorry🤔 Cheers, Doug 😎