Walked into the boot sale this morning and saw this from 50yds. It's a Sea King needing some love and attention. She is 27.5" long with a 9" beam. Twin como motors, futaba 2ch. receiver and Etroniks Probe ESC. Along with battery and Ripmax Transmitter. I have nearly finished my Dolphin 16 and the Sea King will be the next project. I will add it to my Harbour but she may be in dry dock for a good time as i sort out the cosmetics. I've included the Dolphin in the photos. What a lucky boy! If anyone has photos or plans as to how she should look I would be grateful to see them.
Hi robhenry Thank you for your complimentary remarks. I didn't really consider building the boat with twin motors and rudders as I wanted to build the kit 'out of the box' to a great extent and also because I was rediscovering the hobby and all of the new technology and techniques that it now benefits from. With the experience I and knowledge that I have now gained I would be not so hesitant to consider such things. I'm grateful for your contribution to Mike's data on the RAF boats as it will have no doubt filtered down to the benefit of my boat build. As I have discovered, surprisingly little information on these boats exists or has been made public despite their popularity with model builders and it would be a great thing if everyone were to pool their knowledge and resources to try and redress this situation. I will certainly try to photograph the boat in action if I can manage the controls and a camera at the same time 😁 Rob.
Yes the Dubarry looks very similar and it says it was based on a thorneycroft.These were diagonally planked as were the full sized ones in the pics.Did not realise they were twin screw as they were afloat!.The chine hull was easier.The engine (A Westbury hybrid with bent pushrods!)is not very powerful but still gives more than scale speed.The bottom end is Westbury mated to an unknown top end,spark is by a car coil and 6v battery and allows a really slow tickover you can almost count the revs and a reliable pick up but seems to be flat out at 3500 rpm so with a bigish prop seems a good motor for the boat just wish I could stop it leaking oil!(crankcase pressure even with a 1/4" breather!)
Bought another boat last week, needed running gear apart from the twin motors and rear servo. So I bought a new Tx/Rx and a new ESC....I used a NiCad battery 1500....now I didn't charge the battery so it could be something as simple as that. The Rx was already bound to the Tx so all I had to do was make the connections and off we go. Nothing!!! Neith rudders nor screws moved a millimeter.....battery problem? There was enough charge to light the ESC and Rx. How long do they hold their charge roughly? Thanks.....
You've almost answered your own question! ESC: If the motor stalls, weed or plastic bag etc round the prop, the current drawn will rise to 70A. If the ESC can't handle that it will cook 😭 It's a risk that can occur any time on most boat lakes. Up to you if you want to take that risk. If you sail only in swimming pools OK no problem the Viper 20A will do 😉 Fusing: If the motor draws 11A at max efficiency it may well draw up to twice that under other conditions and depending on the prop you use. Therefore the 20A fuse is good. Use a 'slow blow' type. The Viper 20A should be happy with that, they seem to be pretty robust. I use a Viper Marine 10 in small scale models with twin motors without problems. 15A fuse might be safer for your case. Fuse should always be well below the stall current and NEVER more than the ESC can safely handle. To be on the safe side I would put a 15A fuse in the ESC to motor lead and a 20A fuse in the battery to ESC lead. Double this one if you have twin motors! Hope this helps. Doug 😎
Many thanks John.. I,m pretty sure that the 777 will ackle ok.. as there are a couple here with these motors fitted and they do go well with the correct combination of prop, and twin screw, twin motors 777.. I may well hold you to that statement John about the Brushless motors.. Thanks for the interest. Muddy....
It may be a transmitter/receiver problem or it may be in your drive setup that rears its ugly head once your on the water and your motor is under load. I had a similar problem with a twin motor setup which was fine out of the water but after 10 mins in the water I would lose drive to one or both props or one would slow down and just go round in circles (very embarrassing). I had no problem with radio setup so it had to be in the drive chain. I ended up changing both motors for ones with more armature poles, higher torque output and a different gear ratio. It also highlighted a problem with my first choice of battery which quite frankly were pants and used to produce similar symptoms as you describe. I now use Lipo power packs, they do have disadvantages but you can not knock the power to weight ratio. The main problem I was having appeared to be down to the 3 pole motors that were fine until they were under load, this caused the motors to overheat which in turn increases the current drain on the battery's, the net result is the motor starts to arch across the commutator and effectively becomes a dead short which in turn shuts down your ESC's or drains your battery's very quickly. As you probably know if this was to happen with Lipo's there would be no need for a smoke generator! Of course this only applies to brushed motors if you are using a brush-less motor then it will probably not help you.
quite a few years ago I was asked if I could make a model boat hull for a friends son. As then a laminator it was an easy job after making the plug to the approx specs asked for. I made the plug and mould then cast a test moulding asked if i could keep the test mould and was told by all means have one. The mould was handed over when completed and payment ect was made. The test moulding i just stuck in the loft Not knowing I would ever start modeling boats so much later in life. So Now I am into the model boats hobby. Here is the hull with twin outlets for the propshaft. And progress so far with the superstructure. Approx 51 inches long 17 inches wide and a depth of 11 inches. As I was paid to do the job nothing in the end belonged to me except the hull I was told I could have. In writing I may add.. Made a flat sheet of laminate and enclosed the whole hull on the top. Cut out an area for the superstructure and as you can see I have started a rough looking superstructure. I have no plans or drawings for this so it will go where ever it ends up I guess.. Apart from the hull I plan on using ALL recycled materials from our local tip. Paint .Plastic and everything else... The big idea apart from saving material from the tip is to make the model at the lowest possible cost. Motors and some other electrical parts will be removed and put into this model from the Ayton cross So all the parts will be transferable from model to model. Well thats the plan anyway. Guess I will have to wait and see how that goes later. Prop shafts props and rudders will be new so NOT replaceable. The timber so far a lump of 4x2 from the tip Free all cut down and sanded. The superstructure I have used a large fliptop plastic white bin from the tip again £1.00 Superglue bought from the local £1. shop. Filler and sanding paper I already have. So I have started it. I will update as I go along..
Hi guys need a little advice, I am finishing off a US Coast Guard Boat with twin props one left and one right handed, my question is if they are handed do the motors have to be wired up diferently i.e. One wired minus to plus and so on.
4ft model Riva Aquarama sports boat for sale, as featured in 'Model Boat' Sept. 2011. Mahogany build. Immaculate. Radio controlled. Twin electric motors. All batteries, controls etc. Hardly used due to bereavement. Based in Coventry UK. £300.
Hi Dave, good to hear from you (sorry to hijack thread). 4 footer came out two years ago, Huntsman once in 2016, Its over 3 years since the 3 footer got wet! Orca once in 2016. I did build the PCF which I really liked, but it went immediately as too many people messaged saying they wanted it, so it funded some RC plane gear, which I am really into now. I sold a load of bits and bobs at the Blackpool show a few months ago, didn't renew with St Helens in 2015, or 2016, and wont this year. However.... Robs excellent blog has got me interested again, and Stephen kindly did a bespoke 3 d printing project on something rc related, info and pics to follow when its finished! Back on track... George, I'm going to advise only things I have done, or used, I'm not one to say do this, or that, but actually I have not done it myself. No doubt others will disagree, but this is my opinion only. Best performance in terms of speed is brushless, and lipo. Forget fear of fire and explosions, this only happens with abuse, and they are the common use with rc planes, helicopters, cars, its only boats that are really stuck in the dark ages with technology that have this big fear of brushless systems and lipos! However, to get initially set up, they do take more understanding and initial cash outlay, as you need a specific charger for one, and you do need to understand what you are doing. Brushless motors will unlease the power far more than brushed, and are usually lighter. https://hobbyking.com/en_us/turnigy-t600-brushless-outrunner... This motor is an example, there are much cheaper ones with similar specs, but I have used this motor in various applications, the most similar to your boat being my large Huntsman, with this motor on 6 cells lipo I achieved 25mph, but speed might not be what you want. So if you have the fast engine in your car, say a v12 Ferrari, if you run it on cheap fuel, it wont perform, same here, nicads and nimhs batteries are easy to maintain, you can drain them dead flat, but will give cheap fuel performance, like a bath tap trickling when the shower is on at the same time, and as they are dying technology, are expensive for what they are. Lipo is like turning up both bath taps and the force floods out, but now the tank will empty quicker, so you have less run time 😊 If brushless, its a specific speed controller, https://hobbyking.com/en_us/hobbyking-50a-boat-esc-4a-ubec.h... and you pay extra for reversing (other rc disciplines don't need reverse) and a marine esc might need to be water cooled, however, decent brushed motor speed controllers are not exactly cheap, so now you know why budget is important to give advice, you could be spending £100 here just to get up and running. Look at my 4 foot fireboat build blog, as its twin screw (personally a boat this size is better twin screw) you can get by with cheaper motors, mine where £30 the pair, I use lipo for all my boats, so I have the batteries, and are familiar with using them, the speed controllers where about £40 the pair, and if I was buying batts then probably another £40, so it all adds up! Single screw, less batteries. You could power with nimhs, and it might be acceptable ,performance for you. If your location is Ellesmere Port, have a Sunday morning drive to Hoylake, then New Brighton, and maybe take in St Helens Liverpool, and Runcorn, see boats in action, see what sort of performance suits you, and rethink the budget, what do you want to spend? Then you need the transmitter and receiver (if you don't already have these) the fittings (see Robs build blog) a prop shaft, and a suitable propeller I am North Wirral, you are more than welcome to come and have a chat and see some boats, but unfortunately I'm deep into another rc project for the next few weeks, once that is done I can share some time, if you want! Don't worry, I'm not all about speed, I can do brushed motors and nimhs and get a result, Any questions, just ask, Paul PS... Looks like a nice clean boat you have there😉
George, is it single or twin screw, and what is your budget, motor, speed controller, transmitter, receiver, batteries? Do youi want to go fast for say 20 mins, or plod for ages! Then I can advise...!👍 Paul
Hello Skegness..I am using 2 E-Max GT2820/7 brushless Motors. These Are UK purchased from BRC Hobbies (based Northolt) Cost £20.95 each.. these are 850 KV..using Twin Mystery RC 70A Forward Backward 2-7s Brushless ESC (with Ubecc) about £20 or less on EBay (HK). Run Time..1 Hour, mix of fast and slow Sailing..Depends on use. Using 2 X 7.2 NMH Volt Battery Packs..at 5000mah each. She Goes Like fast, and cuts through water lovely. Have A Similar Setup (Different Emax Motors) In my Models By Design Interceptor 42 Boat (42 inch length)..Tooo Fast for me..lol..Any Other Info PM me for phone number..Happy Sailing
Thanks for that. Mine is already fitted with twin shafts and a friend has suggested that I use two 900kv outrunners with 60amp esc's. I notice that you are using an Mtronics sound system, I assume for the motor sounds. What sound do you use as I understand that these boats were fitted with gas turbine engines?