Thanks Dave, Hector Read model powered by a speed 600 brushed electric motor with an electric speed controller. This gives plenty of oomph when it comes to rescuing stranded craft large or small on the pond, which is always a challenge I can never resist.
Many thanks Dave and Brian, I guess Brian's craft is much bigger and heavier than mine; 56x30 cm. Spec says weight 1.3kg with motors fitted but without batteries and RC gear. It came with a 9cm diameter 3 blade ducted fan, 13x? two blade thrust prop and a pair of 400 size brushed motors, the mountings for which limit me to 28/30mm diameter brushless. When I hauled the kit box down from an upper shelf to investigate I found the packing list and spares price list in both Deutschmark and Euro, i.e. circa 1999/2000!! Planning well ahead for the retirement 😉😉 In mine there are no rudders! The whole motor/prop mount is turned. Will see how it goes with that and maybe mod it later with rudders depending on how easy it is to control - OR NOT😲 many thanks for the tips 👍 Doug
I’ve decided to go brushless instead of brushed with a view to adding brushless at a later date. I had a turnigy motor and Hobbyking ESC sat in the spares box and have ordered another pair. Will run this on 2S lipo to start with and go 3s if needed, depending on the watt meter results?
Cheers Dave, some good stuff there. Are there smaller 12v SLA than the giant house brick I have in my aerokits Solent? Don’t want to sink it with a huge brick lol. I may look at a brushless conversion at a later date, would be easy enough to swap out the brushed motors and replace. It’s just that I have all the brushed stuff available that was going to go in another model, may as well use that first. I have battery warning devices for my aircraft, but they are lipo only, will have to look for sla types?
Graham That sounds much better and will move your boat at a very fast speed. I must reiterate my previous advice repeated by BOATSHED regarding the extra support for the prop shaft at each end and adjacent to the bearing. Unlike brushed motors, brushless accelerate to their KV rating at a very fast rate and if your installation is not solid (as concrete) you will experience all kinds of problems, all costly, and often terminal (personal experience confirms this). Finally do get a wattmeter and check the amps and wattage whist holding the boat in the water. If either are above the rating for the motor, ESC or battery you need to reduce the prop size. I can't emphasize this enough as the consequence can be an explosion on the water and total loss of the boat and all its equipment. Asw you have mentioned 10000 mA I assume you will be using two 5000Ma batteries in parallel. This is OK providing you use and electronic coupler between the batteries to disconnect a discharged battery to ensure no one battery discharges below the recommended value. These are not cheap and personally I would use one battery and change to a new battery when the first was depleted. I accept that if you are in a racing situation this may not be possible, but I suspect as a newbie you are using for pleasure purposes. I hope you will now be able to proceed to install the new motor and prop shaft and supports as suggested. Please keep us posted and I look forward to seeing your model on the water
Hi gord(on?), so far so good👍 For heaven sakes DON'T GIVE UP! 😲 If all else fails - use bloody great nails!! 😉 In this case perhaps a half decent brushed motor, the 'Flowers' weren't greyhounds anyway 😁 More power to your boiler, Cheers Doug 😎
Thanks Dave, In common car language that is a V12 in a Ford Fiesta, with the Fiesta drive train. In some ways I believe the brushless motor manufacturers/sellers are responsible for the confusion. Mostly we see the kV, physical size and the number of Lipo cells required. You need to dig deeper to find out the Watts. The kV basically gives the RPM only. No mention of amps and power. We don't buy cars and motorcycles based on the engine RPM do we? Typically if you look at the reputed Graupner Speed Brushless range, they have low kV specs, but the differences between a 400kV 7.4V, 400kV BB 11.1V and a 400kV ECO 14.8V are 130W, 1100W and 2010W respectively. A huge difference. When viewing the on-line retail sites, including Graupner, they all look the same (maybe the same photo), but they are all very different motors. Without the rated amps and Watts (not published) the buyer is left unclear as to what they should buy. Brushed motors are more clearly defined. I must thank Doug for helping me out with Graupner brushless specs when I required assistance.
Hi John, you might now be scratching your head, and wishing you have not asked the original question! This seems to be a common issue, as the boating community is light years behind the other disciplines, rc cars, planes helis and so on, its probably due to the facts general boating doesnt really need the later generation technology, the average boater age is probably higher than the other disciplines so budgeting might be an issue, and there is less younger blood in the clubs to explain the lipo/brushless etc. We see posts with a load of numbers, specs, warnings etc, its enough to put people off. Im a big fan of brushless/lipo/ 2.4 etc, been doing it for years, its cheaper and more efficient (once you have the basics) but for the average guy, who just wants to spend an easy afternoon at the local lake gently cruising around, brushed motors, nimhs batteries, even lead acid, will do the job👍 Your 4 foot ply boat, once painted, with fittings, will be heavy, I know, I own one. Those 600 motors are not big enough, they are better suited to the smaller 3 foot boat, then, pushing them with a 6v lead acid, just cant do it. The battery will be screaming HELP!! I started 15 years back exactly the same, 600 motor, 6v battery, massive 50mm prop, I knew no better and took advise from people who didnt know what they were talking about😡, remember those gold hi tech speed controllers!! I had one, it melted, literally melted on the first use😭 Get 700 size motors, they will need to be water cooled, as mentioned by jarvo, the nominal voltage or below isnt good enough, power them at the max voltage. Brushed means you can use one apropriate esc, look out for electronize (are they still in existance?) or mtroniks, preferably use nimhs batteries over lead acid with a high mah. If after all this you want to venture into lipos and brushless motors, go to a club, spot a boat that is similar in size to yours, if you like the performance talk to the owner and gain experience and knowledge that way, it will save money, lost time and a lot of disappointment, I have been there so feel your pain. I say I would never go back to brushed motors and none lipo batteries, but I always want silly speed, not runtime, after 15 minutes Ive had enough and am bored. Rambling over! My 4 foot boat is twin brushless and uses 4 lipo 5000mah cells per motor, it will do 25mph for 15 mins, then I go home😁 Message is, you can get a "reasonable" performance from brushed motors, with the correct batteries, right props, but weight is the enemy. Looks lie you are at Biddulph, get onto Dave M a moderator on here, and arrange to go over to see the crewe and district boys on one of their sailing days, take your boat with you, they will help👍
Hi peter, do you want a brass 3 blade prop for cosmetic reasons, if so they do look nice. I did extensive testing with my 3 foot fireboat using brushed, then brushless motors, and then prop testing. I was using eagle tree data logging for watts, amps, gps speed etc. The plastic two blade cheap as chips props actually produce similar readings to the more expensive brass 3 blades. Personally, as you are at the "guess work" stage, just use the plastic two blade ones, but use "x" pitch, standard wont give you the speed. Get a few sizes, 30, 35 40 mm and test. When you have the optimum set up you can then go to the expense of the brass prop. I sent Simon Higgins (ex prop shop) my readings and he made a specific prop for my boat, its a 35mm cleaver 3 blade. He has his own company now but I've forgotten what it is! He was at Blackpool last year so someone might have the list of traders. His props are balanced and one piece, very nice. I also experimented with a belt driven gearbox. The set up I have at the minute is this motor https://hobbyking.com/en_us/turnigy-t600-brushless-outrunner... overkill really! but my 3 footer is an original very heavy aerokits boat.
so following a plea for a cast off boat for a friend, Dave generously donated this hull, its very nice. We discussed a gun boat, in a stand off sort of scale, as he likes military, with perhaps a superstructure that can be removed, and a different one made to fit, so two boats In one. But the more I look at it, the more I think it would make a minesweeper etc sort of thing. I'm not that well up with this sort of craft, its 43 inches long, so quite narrow, It has to be pretty much "none fussy" as the owner and builder is relatively new to this, Ill help, but its his boat, and he has clumsy hands, 😊 so it wont be super detailed. Easy to use, so single screw, more than likely brushed motor running nimhs or even lead acid (ouch🤓 that goes against everything I do!)_ Ideas please!
A challenging project 10 years ago. Scratch built model of theSRN3 built under licence by the US for use in the Mekong delta against the VC in Vietnam. Very light construction with liteply. Two ESPs control brushed and brushless motors for lift and propulsion. Motor tube ball-raced at each end with a 9x6 pusher prop. Realistic performance and sounds like a turbo prop. Tricky to control in anything stronger than a light breeze. Best on water.
Hello Colin This model has two brushed motors and ESC/rudder servo fitted along with custom made crew members (realmodelpilots.com) OA length is 30" and beam 9" ps nothing ate me but I are looking for 120.00 or vno Hope this helps Thanks for asking Bill Further photos are available for anyone interested
Hi. I am building a 35" version of the aerokits RAF fire tender. I am at the point where I need to decide on the electric motor which is appropriate. I would like the vessel to be able to come upon to the plane without to much effort and have a bit in reserve for anxious moments or sheer fun. Do you recommed a brushed or brushless motor and if so what power rating. If brushless either in runner or out runner. Grateful for any advice. Regards Kevin.
Hi Chris, glad to have helped, having already been down that road and learning the hard way! 😉 Actually Raboesch is a Dutch company. Not quite Double Dutch but in the case of 'Left - Right' props close to 🤔 Your boat: Rother class, OK so it's a slow (10knots) displacement hull. With bilge keels which make turning more difficult. I would probably use two brushed motors cos you don't need the Oomph of brushless. With brushed you can then use the Action Electronics Dual ESC and rudder mixer, P94Lite. From Component Shop. See pic. https://www.componentshop.co.uk/action-electronics/esc.html Good for 10A continuous to each motor - brushed ONLY! I'm about to fit one to my 5 foot Graf Spee. With the hull form of the Rother only sea trials will confirm which is best outward or inward. have fun with the build and trials, looking forward to updates / pics / vids 👍 BTW: will yours also be Self Righting??? 😉 Cheers Doug 😎