|Diede van Abs||13/09/2014 21:38:02|
|192 forum posts|
A bit late of a reaction, but anyways...
The whining at low speeds is largely due to the ESC switching frequencies you hear through the motor, and that is probably also what you hear, Ashley. However it could be that there has been a bad batch, or just one poorly designed motor type - HobbyKing has pretty good quality control.... for chinese standards... so it might entirely be possible that this SOMEONE on the pond has either a bad q motor or a lousy ESC.
My experience with the gold colored Turnigies is quite good. Having said that, I don't have much experience with brushless motors outside of HobbyKing's range, and I don't have any hands-on experience with inrunners (what I and Gareth have are outrunners).
All the projects I have on the bench now, will have similar motors...
|Gareth Jones||21/11/2014 20:32:36|
791 forum posts
Progress on Spider J has been slow but positive. Slow because I have returned to work for the winter again, become secretary of Goole Model Boat Club again and had to fit some sail winches in my wife's yachts again. On the other hand I have also, for the first time, started some experiments with brushless motors, built a Vintage Model Boat Co. Mr Tom, partly as a club have a go boat, partly to take on the Manx Model Boat Club's fun competition and partly as a brushless experiment. I have also begun to refurbish my one and only yacht, which sprang a leak last year and begun to design the flight control system for a 1/4 scale replica of a Blackburn special purpose seaplane to celebrate the 100th anniverary of the Brough site for BAE Systems. Brough is the oldest aircraft factory in the world, where I have worked on and off, but mostly on, for the last 45 years. The SP seaplane was the first aircraft to fly from Brough and the replica is being built to celebrate the centenary of the site in 2016.
However enough of my troubles, here are a couple of pictures of Spider J, which has started to look more like a real barge with the flat bottom and side skins fitted and the start of the planking over the areas in between.
The main skins are 2 mm ply and the planking is 2 mm lime in various widths, mainly 8mm, 6 mm and 4 mm.
|Bob Abell||22/11/2014 07:19:49|
8921 forum posts
What a complex construction?
Are the bulkheads true to scale?.....The stern looks very curvy and a tricky planking problem?
250 forum posts
I can only admire your skill, craftsmanship and patience. Amazing piece of complex carpentry. Look forward to seeing the progress on your build. What adhesive are you using to glue the frames and stringers (not sure that is the correct term - what I mean is the longitudinal component that goes across all of the frames). Do you steam those parts of the wood that curve at the stern ?
I imagine that the "1/4 scale replica of a Blackburn special purpose seaplane" is quite a sizeable aircraft. You also refer to repairing a yacht - is that model yacht or one that sails on the high seas ?
After a little bit of study I found that there is no mystique to brushless. The clever bit is in the brushless ESC which generates a phase locked 3 phase waveform. I use Mtroniks ESCs (both brushed and brushless) and have never had any problems.
|Gareth Jones||22/11/2014 20:17:15|
791 forum posts
Hi Bob and Ian,
The structure is not really very complicated at all. The frames are all the same outline shape and position as the real frames and they are taken from the original Warrens Shipyard drawings. Generally I use aliphatic resin resin glue for the frames, stringers, skins and planks. So far I have not had to steam any of the planks but the ones that curve around the bow and stern will probably need to be soaked in boiling water for a few minutes and bent around a former to take up something like the right shape before they are fitted.
The Blackburn SP will be around 18 feet span if we build at 1/4 scale and 25 ft if we build at 1/3 scale, to be powered by a pair of two cylinder petrol engines and, ideally to be flown off the River Humber alongside the factory just like the real thing 100 years ago. However we are going to practice off a hard runway first.
The yachts are only models, but Elizabeth's latest aquisition is her biggest yet, a 10 rater which is 80 inches long with a mast 96 inches high. It's a complete free sailer at the moment, no means of directional control, which is one of the reasons the previous owner sold it to us. Eventually it will be converted to dual control with the option of radio or a vane steering system.
I agree on the brushless motor situation, no great drama and not really any more difficult to match a motor and propellor than brushed ones. I now have a couple of brushless options which work well included in my database. Maybe I should update Colin Bishops thread of a few years ago or perhaps I will wait till I have got round to writing my planned Model Boats article.
|Gareth Jones||30/11/2014 19:12:58|
791 forum posts
Quite a bit of progress with the planking this week. The upper part of the bow has been done with 30 mm wide strips of 2 mm ply. There is very little double curvature on this part so wide strips cover a bigger area more quickly. However they did need a bit of boiling in a pan of water on the stove to soften them first. I clamp them around a suitable sized tin while they cool and dry in a reasonable curve to fit the hull without too much stress.
Four strips each side and the easy part of the bow is done.
The next bit is more tricky as the shape becomes curved in two directions so narrower strips are the order of the day and one edge has to be tapered to get the strips to lay as flat as possible on the frames.
At the back and along the side its much easier. I quite enjoy trying to work out the best area to work on where the planks will lie with the minimum of bending and twisting. The back end will be fairly tricky and need a bit of steaming to get the planks to bend around the stern.
I was pleasantly surprised to find that I could plank along the lower corner of the hull side using 8 mm wide planks. I thought I would need narrower ones because of the curvature of the frames but because its a long straight run the wider ones worked OK.
I think the next step will be to complete the other side to the same point and then move on to the stern, starting from the edge nearest the deck.
Oh, and by the way Bob and Paul, the prop shaft angle is exactly horizontal, no compromises here.
Edited By Gareth Jones on 30/11/2014 19:15:46
|Bob Abell||30/11/2014 19:35:57|
8921 forum posts
With complete respect........Is this mixture of hotch potch planking, based on the real thing?
How will it look when painted?...........Just nit picking, don't take offence
Now then......What about these horizontal propshafts?......I assume the full sized barge didn't have propshafts
So how are you achieving the so called impossible?
I suppose the props need to be above the hull bottom to prevent damage?
|Gareth Jones||30/11/2014 20:00:37|
791 forum posts
This hotch potch planking is fine. It will be covered by a layer of glasscloth and resin and then some simulated steel plates and rivets to look just like the real thing - Spider J is a model of a steel hulled sloop. The earliest keels and sloops were wooden but I dont think any have survived, or any drawings of them so I don't know what the real planking looked like. However there is a nice half model of a wooden keel in the Maritime Museum in Hull.
Most keels and sloops were fitted with motors, starting in the 1930's. Heres a picture of the business end of one, I think it is Phyllis but I am not sure. Note the horizontal propshaft. Not that difficult to achieve in a Humber sloop model, just a matter of picking a motor with a suitable diameter and mounting it low down in the hull.
|Bob Abell||30/11/2014 20:42:24|
8921 forum posts
Thank you, Gareth
All is under stood now, I should have known better.........Shades of the hamster blooper!....eh?
I like the prop.....But why was it horizontal?
|Gareth Jones||30/11/2014 21:28:25|
791 forum posts
Because horizontal is the most efficient angle.
If you mounted it with the propellor axis vertical, all you would do is stir up the mud on the bottom of the river.
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