Here is a list of all the postings John W E has made in our forums. Click on a thread name to jump to the thread.
|Thread: Three props|
You are quite correct, there were several MTBs and MGBs built during the War which had all the props turning in the same direction. One of the main reasons was a short supply of the reverse gear boxes. To cut a long story short, after the War, they did experiment with configuration of rotation of propellers - they found there was a slight improvement in speed with all the props turning in the same direction - but - only a slight improvement.
One of the most notorious vessels that Royal Air Force had built was the 68 ft RTTL It originally started off with 3 props but then was reduced and re-engine to have 2 props (all rotating in the same direction) and this vessel was renowned to have prop walk especially when diving off the top of a wave at speed. On numerous occasions, several of these vessels, split the hull at the bow. So, what Vosper tried to do for one of the fixes was add an extra layer of planking to the bottom and then they experimented with an aluminium hull.
If I can find the pics, they will follow
Edited By bluebird on 12/03/2017 19:01:10
Edited By bluebird on 12/03/2017 19:01:37
Edited By bluebird on 12/03/2017 19:02:04
Hi one of the main reasons the rudder is off centre to the prop shaft is that the thrust from the prop isn't even on either side of it. There is more thrust on one side therefore you place the rudder in this side of the thrust flow to make the rudder more efficient. Also smaller diameter props are used with coarser pitches to help with cavitation on high revving engines - here are a couple of pics of the real I am (Vosper perkassa).
Edited By bluebird on 12/03/2017 10:33:07
Edited By bluebird on 12/03/2017 10:33:51
|Thread: Quick question|
Many moons ago, there used to be a bloke called Mike Mayhew; he used to build Thames Barges from cornflake boxes and they used to sail. The old Man Dave Milbourn's friend Riggers, used to know him well. How he used to seal them, I believe he used to coat them with resin I believe. As has already been stated personally I wouldn't use MDF in water due to the fact that it falls apart when damp. Plank with either cedar or lime and plywood frames and make plenty provision for lead ballast in the bottom of the hull. Seal the hull with epoxy resin.
Edited By bluebird on 11/03/2017 09:39:57
|Thread: TEV Wahine 1/35 Build|
hi there Richard
Good few year ago, I built a model of the Moray Forth a Coastal Cargo ship, although, only small compared to the one you are building - I assimilated the plating on the hull exterior, the same way you are planning on doing - I used 0.5 thick Plasticard - I used the thick variety of Superglue from GRIP - much later, when I have completed my model of HMS Exeter, which is roughly 70 inches long - and I followed the same procedure. For tight curves and places like that, I preformed the Plasticard around a variety of different diameter round steel tubes - and I warmed the Plasticard in hot water. So far, touch wood, I have completed 4-5 models using the same method and the plates haven't detached from the hull. Using a thick grade Superglue allows you to move the plates around. I also used a small wallpaper roller; the type you use to roll the seams on wallpaper - to roll the Plasticard to ensure there were no air bubbles underneath it.
If you want to include rivet detailing as well - the method I used was an old brass cog well from an alarm clock - mounted on a handle to allow the cog to rotate. With this and the aid of a steel ruler; I could do rows of rivets on the edge of the plates.
|Thread: Classic boats at Chichester|
Hi there Paul
I take it by your last statement that you are more of a book basher than an actually hands on designer builder of the real item. If you were actually involved in boat design you may realise its not off the cuff and its as simple as that. You have to make many compromises and many adjustments in the process of design/building to achieve the ultimate goal - of either personal requirements or the requirements of the customer.
Yes, I did design and build a hull that I am pretty proud of.
Paul, tongue in cheek, you and I could discuss for a long time the subject of the different designs of props and the rights and wrongs - such as surface piercing props with flexi drive; z drives; with counter rotating props - and we could go on forever. But we would only drive them asleep here on this forum. There are so many things that can be prove wrong - especially with a zero angled drive.. Peter Du Cane was my bible during my design work of real boats.
Edited By bluebird on 26/10/2016 20:04:56
hi ya there me marra
what's this about prop shaft angles eh? here is me reaching for me bible of all bibles - you cant argue against this guy - what he says is RIGHT - Peter Du Cane - from Vosper. I have several of these bibles from when I used to build the real 'I ammers' and somewhere from the depths of me mind from one of those books - it states - the angle of a prop shaft should be in the region of 13 degrees for a deep V hull of multi engine construction e.g. the Surfury and them rubbishy boats the erm erm what do you call them boats again that Mr Dave M likes nice looking boats thos isn't there in Colin's pics - yes sitting on the aft deck drinking Champers - but in my case cheap pop from Lidl or Aldi haha
|Thread: Vic Smeed's Model Boat Designs|
LOOKING at the top pictures doesn't half bring back some nostalgic memories, some of them painful. The Sunday morning standing at the lakeside smelling of Kiel Kraft diesel fuel stinging fingers with cuts where the starting cord has cut into your fingers.- the darn things still wont start because the chances are you have flooded it that many times and after about 20 times of trying to start it the thing fires into life. You set it away on the lake and what happens - engine failure - right in the middle of the lake. So nothing more to do than sit on the bench at the park side waiting for it to drift in on the wind, along with several other boats. I couldn't afford a radio control those days
|Thread: Fitting out a tug|
Hi there Martin
These motors you have - the Johnsons 555 - do they have a fan in the rear of them inside the casing? If so, these are beasts to say the least - rather too thirsty on the amperage I would have thought. I have 2 of them mounted in my RAF Rescue Launch - and it planes across the water very nicely on 7.2 volts. Each motor is eaten away nicely at 15 amps driving a 35 mm x 3 blade prop. So please be a bit wary of using this type of motor in a model boat.
As for sealing the prop shaft, this is a long and well debated subject - but - it all boils down to the majority of us using either a grease of some description or a mixture of grease/oil. I would suggest that you do a web search and make your own decisions on the topic.
I helped a friend build his first model of the Sun XX1 tug from the MAP Plans way back when you could buy a pint of beer for less than 50pence - the motor fitted then was a 540 MFA - it was fitted to a 2:1 belt drive gear box which sadly seems to be no longer available from MFA - anyhoo - I know the model has gone through many a revamp and I believe now it is sitting with a 555 motor from Component Shop - rated at 12 volts - but I believe he runs it at about 7.2 driving a 3 blade 50 mm brass prop. Now if we go over to Mayhem - I built the MSC Archer which is a slightly smaller tug but it has a 4 blade 50 mm prop fitted. It is also fitted with the 555 motor running on 7.2 and it has an ACTion speed controller of the 10 amp (I think its the 10 amp one) and that goes along at a fair wack on full throttle enough for the bow wave to swamp the model - so plenty of power.
Edited By bluebird on 24/09/2016 09:53:24
|Thread: TEV Wahine 1/35 Build|
This is the closed loop system of rudder linkage on HMS YORK
with 2 rudder set up
Personally I prefer the closed loop system of rudder linkage. This is where you have 2 push rods from the servo going to the arms of the rudders and the rudders are connected with a tie bar - all adjustable. The reason for this is it evens out the stress on the servo. Think of a man riding a bike using one hand and one arm to steer on the handle bars. Its a lot easier if you have 2 hands on the handle bars to turn the corner.
I have including a pic of one of my models - admittedly this is a 3 rudder model - but the system is still the same.
Hi ya Bob
When the jig was first made I heated the whole lot up on the gas ring to do the silver soldering on the A Frames. Consequently I was banned from the house not only for the fumes, but from marking the top of the hob so in came plan B. Out with dad's old paraffin blow lamp (the old fashioned type) built a small hearth in the garden from firebricks and set about singeing me eyebrows whilst trying to light the blowlamp. Can you remember old 'prickers' for trying to clear the jet out. That was quite successful - I learned that if you place it on a firebrick and heated the whole lot up - it maintained the heat and I could silver solder it with a small butane gas torch as long as I heated the bricks up with the old blowlamp. But, for the smaller models such as HMS York and soforth I tend to soft solder the A Frame- because - to be honest I don't think there is much stress on the A Frames if you have your shaft alignmet set up correctly.
Edited By bluebird on 11/08/2016 17:55:01
I am a bit like Bob, I don't like the comment on such excellent work because it puts my offerings to shame, However, to help you out making your A Frames for your prop shafts, have you thought of making a simple jig similar to the one I constructed when I built HMS York - the type 42 Destroyer and also several other warships.
I have put a little picture on of the jig which I made and the way I get the angles of the legs is to put little packing pieces under the legs to alter the angles.
I hope this gives you some ideas,
|Thread: Power Boat Surfury|
Hi there William
I received your emails and sorry for the delay in responding,
When I originally built the model of The Surfury there seemed to be a lot more information and drawings available on the web. The one drawing I was looking for, and I have been trying to research is where there is a cutaway view of the Surfury which shows the position of her fuel tanks and if my memory serves me well, the 2 main fuel tanks are mounted either side of her twin engines (on the Surfury the 2 engines were in line driving fore and aft through a central V gearbox).
I am sure I remember reading that the main purpose of the ballast tanks, at the bow of the boat, were used to compensate the usage of fuel - as the boat progressed in the race (as the fuel is used the centre of gravity moves in the boat) and to bring it back to the central position for optimum performance, they would either pump water into the tanks or remove water, whichever was the case. Also to assist with the trim of the boat there are powered trimtabs on the stern which would be adjusted accordingly to bring the bow down.
my personal opinion, is that it is the worst thing to do to add weight to a performance model. My recommendation would be to dispense with the weight in the bow and move the batteries as far forward as is possible towards the bow and ensure that you incorporate adjustable trimtabs at the stern of the model and this way you will be able to trim the model to run the model at the correct trim and also keep the model as light as possible to get a greater performance.
and what do I know I am just a bluebird duck
Have you had any joy with the motors for your harbour defence motor launch - the reason I am asking is that I have been going through some vintage model boat magazines and I came across Radio Control Boat Modeller - October 1993. There is an article in there which is written by some guy called Paul Freshney - he built the award winning model from a plastic hull. I am trying to find out which type of motors he has in it. I suppose you could email the guy on this forum as he is now the leader of the pack for Model Boats Magazine and he may be able to assist your goodself.
|Thread: Power Boat Surfury|
I also built the Surfury a while ago, I used the Myhobbystore plans. Although the plans are a bit vague there was an article in the Model Boats magazine, I think its a 1969 issue - or circa ....where the hull is diagonally planked and soforth. In my model I fitted an I.C. engine and that was an Enya 19 model - it was purely built for nostalgia that model. I have tested my model in a test tank i.e. a rather large paddling pool - and basically that is as far as it got. The model still needs finishing off. The thing is with these models, and which you will already realise - with the hull being a steep V shape, they are brilliant in going in straight lines, but, when you try and turn them they are a nightmare. As far as powering it with brushless, I will be honest with you, I don't have a clue, because brushless is still a new field to me - along with lipo batteries & etc.
Couple of pics of my attempt
|Thread: My first ship|
Hi ya Bob
here are a few memory jogs for ya:
What is red and used to come to your front door and go put put put put put - with a man with a little blue uniform on....telegram boys haha
they used to deliver your telegram
dear sir, please pick up ship at so and so point ... maybe Liverpool Docks .. it was for me
can you remember the night before, checking all your stuff in your suitcase. For me, as engineer, it used to be 3 white boiler suits, one of them with no arms and cut down to shorts - cos it was very not in the engineroom. Then dress for the tropics - 3 pairs of white shorts; 3 shirts with short sleeves, 3 pairs of knee length socks, pair of white plimsoles; epiletts with your rank etc. and your Company button on.
and yes, boat was leaving Durban started off only being a run down to the Gulf, and got stuck in Khorramshahr at anchor for just under a month - happy days now that is another story.
For those who have never been to sea, it is an experience I can tell you. Well in 1974 it was. None of your ship to shore phones - we used to carry a Marconi wireless operator and all still done in morsecode and we also had a radar that sometimes worked.
Edited By bluebird on 25/07/2016 18:10:39
but the real one of 1974 City of Columbo down on the Persian Gulf run from Liverpool
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