Hi there, Sorry but Cumbria has no Canals, Lancashire has some 40 miles away. Cumbria has some lakes some covering 5 acres or more all with overhanging trees, poor access, exposed to high winds and rain, and a nice 4-7 mile walk to get to the other side. The Windermere club was about 40miles from me but has no water at present and has not had any for a number of years. I may be fussy, but if something goes wrong (which it often does) I need to get my boat back without too much trouble. It is surprising but even small public ponds/paddling pools have been closed by local councils in-case they get sued. So I travel a round trip of 80 miles to sail at Darlington Model Boat club, a great bunch of lads they have a 80m square pond with access all round, a rescue boat, a club house, toilet and kitchen. I also go to Norwich, Eaton Park when I visit my Dad a fantastic old Victorian walled pond about 30m by 120m. Some pics of Eton Park Thanks Roy
Hi, Lots of factors to take into consideration, 1 specification of motor 2 voltage to be used 3 size and weight of the boat 4 speed you wish to achieve 5 Current limitations (20A) Besides the above if it is a brushed motor and your limit is 20A I would opt for a propeller of 30mm to 35mm (low pitch). The old rule for Brushed motor is do not use a prop any bigger than the diameter of the motor. the bigger the prop/pitch the more current and a hot ESC. Act with caution, put a 15A fuse in line just in case to protect your ESC. It is difficult to give advice there are lots of unknowns.
Thanks Canabus, I have a watt meter, so I know my static (boat not moving) current drain is, but it is just that my nearest pond is 40 miles away to test the boat dynamically. The trouble with living in Cumbria, no safe water for models. Thanks Roy
Hi there, can anyone help with a question about current flow through an electric motor (in this case Brushless). A boat in the bath (static) pulls 25A is there a relationship to what it will pull on open water (dynamic), I know there are many factors involved. I am looking for a best gest-imate or practical experience, for a average planning hull. I once read It was between 10-15% less when moving but this could be for a displacement hull. Many thanks Roy
Finish painting and adding some stickers, and a couple of pictures of the real thing. Fitted Motor in a water cooled jacket 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.
Have added reinforcing to the frame supporting the end of the shaft tubes, 3 pictures show dry fit. and once dry glue in shafts with epoxy resin, 3 pictures of fixed shaft tubes. Now looking at an extra part frame to support the three motor brushless out-runners.
Dry fitting pro-shafts (Note, all shafts parallel with the keel) Drilled with an old prop-shaft which I modified to a cutting tool then finished with a round file and cut slots for propeller-shaft support bracket with a hacksaw, file and knife. Note these shafts are lightweight aluminium tube with steel liners and steel shafts. props at currently 40mm but as with all things scale things are not always practical in scale size such as propellers and rudders and in this case the direction of rotation (not all going round clockwise).
I am after some information on the ELCO 80ft 103 class, I have gathered conflicting data on the positon of the three rudders relative to the propeller shafts. Some say inline, others say outboard of shafts. Port and starboard shafts of early examples were set 47inches from the centre line (keel). The Italeri plastic kit shows them in line. I have seen pictures of a latter boats were the rudders are not directly behind the propellers but not sure about early boats like the 103 class.
After some calculations I find I need to extend the reinforcing for the port & starboard shafts forward towards the bow. Created some wooden guides when drilling the prop-shaft holes and glued them in position temporarily, as you make expect the drill needs to be rather long, so I made one out of an old brass shaft basically sharpening it so it could cut wood. Next job will be to cut out for integrated shaft support brackets (2mm wide and minimum of 35mm long slot) and the tube shafts are 8.5mm in diameter.
Very high standard of models, I have looked on the their face book page and there is another event at the location next year on 30th May 2019. I may just get there, as I often go to Austria normally around St Wolfgang see.
Some Pictures for reference a RAF 43ft Range Safety Launch pennant '1640' and '1651' were built by 'Thornycroft' at Hampton in 1955. The Model Looks good, adding some detail and fittings will make it look great, bear in mind its a heavy boat, so you may wish to think about brushless motors and Lipo batteries, they will be a lot lighter and smaller than the 800 brushed, and lead acid batteries but you need to get advice before going down that road.
Yes, jumped the gun and brought the motors. Already have 3 light weight Aluminium prop-shafts that I intend to use: Tube Length:25CM/9.84inch Tube diameter:8.5mm/0.33inch Shaft diameter:4mm/0.15inch Stainless steel Weight:67 g The Motors will run on 3s -11.1v Three of these (one as spare): High Performance 2808 1400KV 14 Poles Brushless Motor Max Watt: 350W Voltage range: 7-15V Max amps: 35A No load: 1.2A One of these as centre motor or my swap for spare of above: High Performance 2826 900KV 14 Poles Brushless Motor KV(RPM/Volt): 900KV Max Watt: 1000W Voltage range: 7-18V Max amps: 60A no load : 2.2A
Added some strength to the Bow also act as glue points for the bow strips of ply or planking. Created a template of the first section of ply to go on, thought I would mark out the rudders, prop-shaft supports and shaft exit points. Unfortunately due to cost restrictions I cannot afford to buy or have the facilities to make the correct layout of brackets and supports for the shafts, which I feel may not be up to the job when coping with the high outputs of brushless motor, (still that my excuse) So to use my poor-mans prop-shafts (with integral support skeg) I have had to reconfigure the layout slightly but will keep the original 3 prop-shafts and 3 non-scale rudders, but may shape them as per the originals.
I was lucky to be able to get myself a fibre glass hulled Fairly Huntsman 31 this is a model of the 31 ft Huntsman which converts to a scale of 1:11 which is a bit of a strange scale, the superstructure is in a poor state, so I am thinking it could now be changed to a 'Fairly Huntsman 28' which I think looks better. Huntsman 28 The model 34 in long is close to 1:10scale at 34.6in Some History Four Huntsman 28's took part and competed in the 1969 Daily Telegraph / B.P. Round Britain powerboat race. A Huntsman 28 'Fordspeed No 909' entered and completed the London - Monte Carlo race in 1972. Also the same boat set a new class speed record of 51.271 mph on Lake Windemere, in October 1973. The hull is a deep V with single chine and spray rails. The construction was of laminated mahogany, the hulls were cooked in an oven to cure the glue. The twin engines were placed mid ships. Dimensions LOA: 28' 10" (8.8m) LWL: ~24' 10" (~7.6m) Beam: 8' 9" (2.66m) Draught: 2' 6" (0.76m) Displacement: 8160lbs (3710kg)
Finished gluing in stringers a total of 8 in all, started profiling stringers and rudder and stern tube (prop shaft ) supports. An important piece of advice from my Dad is to "make sure every thing is fair to the eye." Meaning it must look straight or the curves must flow, no kinks or unsightly lines. Thus some of my frames had to be adjusted by perhaps padding out or moving the position of the stringer in the frame. Added gluing supports around the bulkheads and other frames this is to support the 0.7mm ply joints until I get to the Bow when I intend to use small strips of ply or wood.
Deck From the construction hand book:- Decking shall be single layer of mahogany plywood, approximately 9/16 inch thick, installed in general accordance with plan, BuShips No. PT486-S1106-411193, subject to development of satisfactory material. Note. I have seen photos of some perhaps later ELCO 80s with planked decks. Planking 62 degrees hull planking angle not 45 degrees as many have used. stern transom at 12 degree angle approximately. Prop shafts of real boat. All three propellers turned in the same direction clockwise looking from rear, not the greatest configuration for a model boat. propshaft angles are around 10 degrees. The centre shaft is at a larger angle to the side ones. The centre prop shaft angle is 11 degrees and the wing prop shafts are 9 degrees. Using these angles may restrict your propeller selection. The centre shaft appears from hull further aft than the side shafts but the propellers are all at the same distance from the stern or transom.
Have been soaking the 6mm square sectioned stringers in the bath for a length of time, over night in cold water or 2 hrs in hot water seems to do the trick. Put stringers in place held by plastic ties or string until dry (24hrs) then remove and refit with glue and the plastic ties to hold in place. Please note, don't glue a wet/damp timber as it will shrink as it dries and pull the boat out of alignment. The blocks at aft are for the three propeller shafts, will be shaped (one has in a later photo) to hull profile. The wood is a very light like Obechi. Please note. The Models main priority apart from cheapness is to produce a light weight hull that is large enough not to disappear on a pond but light enough for me to carry to a pond/lake as my back is not what it used to be.
Just starting a scratch build of a 20th Scale ELCO 80ft PT boat most likely PT 109 at just over 48ins long and a beam just over 12in. Will try to construct with a combination of chine and planking construction (planking towards the bow) still need to finish of frames
From my experience I would suggest 2-3x your motor current rating especially cheap ones from china, I have found that a brushless motor can rapidly draw high currents with fouling of the propeller by weed etc. I would check the current drawn with the propeller you intend to use with a watt meter in the test tank (bath) held stationary increase power and monitor the current drawn this must be well within the limits of your ESC this should show a 10-15% higher power consumption than when moving. The best bit of advice (which I often don't follow myself) is to put a fuse in line Please note some ESCs are not waterproof (avoid) or seal them with silicon sealant, go for a quality manufacturer and the highest current rating your can afford. Cheap 30A ESCs can be ok for low power motors under 10Amps my racing boat pull 60 Amps and is fused at 80Amps and has a 200Amp ESC
Some pictures of my Dad's Norfolk Wherry seen here at Eton Park, Norwich. It will be featured in September 2018 "Model Boats" magazine along with his mates Wherry. It is about 4ft long note my 3ft 72nd scale Corvette looks small next to it.
Brought this completed 72nd scale Revell kit (normally around £125-150 new) second-hand in a local shop for £30 as per photos, no transmitter. changed 400 motor for a geared 540. changed ESC as control was poor acted like an on off switch. foamed bow area and added some plastic supports to the hull as shown, modify battery box.
Primed with white primer and will sand most of this away again. Please note boat is for semi-scale racing. the bow strakes have been reduced as per the real boat bow and perhaps allowing for some shark teeth details to be add as per one of the two original boats P285