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Member postings for David Paterson 4

Here is a list of all the postings David Paterson 4 has made in our forums. Click on a thread name to jump to the thread.

Thread: Portable Engine Model Engineer Article by Tony Webster
16/05/2012 01:48:39

I had considered doing a significantly scaled down version of this engine and would appreciate eventuallly getting the full set.

The basis of my consideration was to try and scale to a point where I could use a 2" boiler and so fit within the sub-minature AMSBC code (no boiler certificate required). I have not seen a horisontal valve engine at this scale, and suspect it will be somewhat trick to get it looking right.

Thread: Not fit for purpose
11/05/2012 04:53:01

Some of this is silly.

Now that's off the chest, the one specific issue that I would have with drawing errors and 'fit for purpose' is with safety. Many of the complex plans contained in ME include boilers. There are two issues with this. Firstly, plans may not comply with safety regulations or standards in different countries, and secondly, they reallly should be checked thoroughly against relevant standards in the UK before republishing - the standards may have changed.

I do recognise that almost all of the discussion in forums like this around boilers highlights the issue and recommends an appropriate procedure - join an club and do the build under supervision of the boiler inspector.

When I built mine, I had the original Harris book and the AMSBC code next to each other when I drew my plans, but its not certified.

Over all, the plans are a great resource to understand how things work that are at an affordable price - I have one on the wall - a wooden toolchest that is an American classic. But then, I also have framed the tech school poster for the Hercus lathe in the shed.

cheers

Thread: Methelated spirit blow lamp.
01/05/2012 08:48:06

I am a huge fan of pressure stoves and lamps in the hands of people who can use them. Mine run on what we call Shellite, not sure but think this is parafin. it is certainly not kero.

Its biggest advantage is portability compared with disposable gas - I could get approval for small quanitities on military aircraft with the right doco and containers. Never for gas - and low temp operations. This is ALWAYS the fuel used for mounatin and cold temp operations because gas will not ignite if the cylinder is not warm enough to miantain pressure.

Having said that - its a good idea to learn how to light one properly.

I would like to find a plan to construct. The concept is simple, but like boilers it would be nice to have a proven design. Can anyone help?

cheers

David

Thread: A useful Stirling engine.
30/04/2012 00:39:21

First success (very small)

I couln't visualise the way the Ross yoke worked, although it seems the most likely path to success with a straight stirling rather than the TMG (still havent come to grips with that).

Last night I dug the son's meccano out of the cupboard, mine dissapeared many years ago in family moves around the country, and built a model of the mechanism.

not sure if that is a model of a model, but for a chap who can usually visualise stuff on plans pretty well, i was stumped. just how does this appraoch achieve the phase change?

anyhow... one small step completed, and my wife was highly amused with problems being brought onto the coffee table. (it was the first 0 degree night for the year in Canberra last night)

Dave

23/04/2012 09:40:32

Guys,

Struggling to keep up- full time employed, Army Reserve, 3 teenage kids and Model Eng means that these projects take a long time to germinate.

Having said that - think I can start to put ideas into a sketchbook at least. Power output for my lights needs to be at 12vDC 1 amp. I still like the stirling idea, and have seen both pohmbic and Ross yoke ideas that seem scalable.

Heat at the top makes sense to me - can always use the waste heat to run the billy. Not sure how to get a ring of fire yet, so diggin into lod mags an online. I'm a bit partial to 'primus', but suspect that I will have to go a long way before the current archives to find an example I can cull for a plan. The Harris boiler book shows a jet, but not how you might convert this to a ring.

Local mates tell me that the Sturmy Archer is now a collectable, rather than a source, but the the local electronics place JayCar may well have something suitable in thier electronics section.

So, more digging yet, and enjoying the rest of the discussion.

regards

Dave

17/04/2012 05:29:24

G'day all,

I have now got stuck into the videos and the references (except the old ME that I don't have acopy of (sorry Lyyric).

I was wondering why you wouldn't use a crank on the TMG to get DC power? I'm really not sure about any of this electrical stuff.

If I can sot out the current information, it seems that I need to be thinking in terms of either a TMG and doing somethig to sort the power, or a stirling of arond 30cc, probably pressurised, and using gass to get enough heat. (given other constraints about camping etc). The generator needs to be bigger than a video capstan drive If that is in the right ballpark.

Not sure my skills are up to the burner, but as a start point, can anyone point me at some plans please? happy for commercial source if there is some assurance of a 'workable'.

regards

04/04/2012 04:30:55

Why do I take this stuff on?

Particularly when it has taken over a year to deliver a new chest of drawers (in brown stuff) to my eldest?

Thanks for the replies. I have now read the Ross book. Very helpful to understand the effort and commitment needed to get a good engine. Needs to be supplemented with a practical start point.

He mentions a series of articles in ME for a small version of one of his engines, unclear if this would be sufficient for my task and before my time in model engineering. I plan on looking into that to get started.

I rather suspect that I need to tackle the generator at the same time, any ideas.

As for the wind up, These lights are used at 10-20 kph on a 1m swithchback track through trees, I scared myself silly when I lost my helmet light and had to rely on the handlebars. 900 lumen is now about the standard, and I am not fit enough to wind a torch that fast

Did like the Harwell, but you are right about the noise.

03/04/2012 00:00:06

All very cool, and thanks.

I knew this would not be a LTD - wrong target as I was after output, not minimising input so at least on the right track there.

I have found Andy Ross's book so will do a bit more reading and research the bike chargers requirements (I have an elec tech mate who was quick to point out the influence of Watt on my power needs. He recommends PV, untill i pointed out that the intent was to charge between night runs)

I'll be back

dave

02/04/2012 02:53:12

G'day all,

Last weekend I was at an event in canberra called The Mont. This is a 24hour endurance mountainbike race, and half of it is done with very expensive LED on head and handlebars. recharging is gerally done a a central point because these events are well out in the sticks.

I have built a partially satisfactory low temp differential stirling.

The idea is to build a small stirling capable of running a generator sufficient to recharge mountainbike lights. How do I start?

The lights will recharge from a lighter socket in the car (some from a USB - and one of my sons is very keen on the idea of beinga ble to recharge his phone while camping, this would also recharge the GPS which would be good).

So the start point is understanding how to build a generator sufficient for that (I have no idea but have recently seen a model using a DVD drive motor, I think that things like regulating the output to protect the device would also be inportant?)

Then the next point is an engine sufficient to drive the gennerator. Ideally, this would be powered from something like a small flame, pperhaps a portable camping gas burner as a maximum, but that is pretty hot.

Can anyone contribute to this please?

I know nothing about the electics/electronics. I know a little bit (not much) more about the engine.

The teenage boys are greatly enthused - it provides a 'really cool' way of being different at a campsite and enabling the electronics on which thier life seems to depend in between bike laps.

Dave

Thread: Tapered head / cylinder interface
20/03/2012 01:03:01

Thanks for all of your responses.

I don't think he was being critical. He is a high scholl tech teacher who has his students building stuff in Western Australia. his hobby is race cars, he builds chassis for then appparently, so he was really pretty engaged.

I had some trouble sealing this engine, particularly the bottom cylinder head, and its still not all that flash. My father is a great fan of the 2CV - he drives one regularly and I dimantled the cylinders for replacement for him not long ago. My current task is fabricating suspension components for a '38 Sunbeam in restoration - broke a slot cutter and had to make a new one, so new skills all the time and not just models.

so, thanks all, and I will think about how to use this. I keep thinking that tapered threads on boiler fittings might be a good idea, but how do you do that on a lathe? Or is it only practical with some sort of tapered die at this scale? Same concept but potentially more applicable at this scale?

19/03/2012 02:15:07

I was showing off my first scratch-built engine yesterday and was asked about head gaskets by the viewer.

He referred to old Ducatti - about which I know nothing - and said that they had eliminated the need for head gaskkets by making the cylinder/ /head interface a tapered fit. He asked if anyone did this as model engineering practice.

Any thoughts?

My model is the Opus Prime from the ME collection vol1. 3/8 bore so pretty challenging to get any head bolt tension with 12BA I would have thought

Dave P

Thread: MEW188 Editors bench letter
14/03/2012 01:56:32

I aspire to this - but it is why at 53 I come home with blood from falling off the bikethumbs up

The Cape


Eight years old with flour sack cape
Tied all around his neck
He climbed up on the garage
Figurin' what the heck
He screwed his courage up so tight
The whole thing come unwound
He got a runnin' start and bless his heart
He headed for the ground

He's one of those who knows that life
Is just a leap of faith
Spread your arms and hold your breath
Always trust your cape

All grown up with a flour sack cape
Tied all around his dream
He's full of piss and vinegar
He's bustin' at the seams
He licked his finger and checked the wind
It's gonna be do or die
He wasn't scared of nothin', Boys
He was pretty sure he could fly

He's one of those who knows that life
Is just a leap of faith
Spread your arms and hold your breath
Always trust your cape

Old and grey with a flour sack cape
Tied all around his head
He's still jumpin' off the garage
And will be till he's dead
All these years the people said
He's actin' like a kid
He did not know he could not fly
So he did

He's one of those who knows that life
Is just a leap of faith
Spread your arms and hold your breath
Always trust your cape

"The Cape" - Guy Clark - 1995

Thread: A forum maybe of interest to horologists
09/03/2012 01:59:32

Great watching Beal develop over time.

I have a 15 year old book with one of his furniture designs in it as a route project - he had developed a system of cutting threads in wood using a 60deg cutter in a small router.

project was a very elegant adjustable piano stool

Thread: Northern Modelling Exhibition
07/03/2012 03:28:13

Thaey dont need to be big to be good. we could do with a decent trade show, but

this is what is available in Canberra, one / year

http://actmrs.org.au/information-types/actmrs-members/malkara

Almost no trade dealers except for railway layouts, but a great mix of steam, dolls houes, trains, cars, planes, boats, sometimes tools.

Place is packed for two days and supports Malkara special school. 95% of the visitors are not yet model engineers. my youngest, now 16, started going when he was about 4, still enjoys it and criticallly examines every layout and steam model on display.

Thread: Milling wood?
06/03/2012 22:39:43

I have not milled wood, but when making the forms for boiler end plates I started them on the wood lathe and finished on the metal late. There is a standard holding approach for wood turning that uses a coarse thread into the back of the work. I simply transferred that screw into the 3-jaw on the metal lathe.

The advantage is that the wood lathe and hand tools are very quick for roughing a blank, the metal lathe allows easy creation of an accurate cylinder - precice diameter, no taper.

david

Thread: Boiler feed pump
03/02/2012 04:35:38
If you look in the mag at the various free train plans, you will find a few examples of small hand pumps fitted to tenders.
 
Take one of these, replace the bottom input with a pipe fitting from your water supply, and add a base to the mounting points. Mine looks a little untidy, and as my first effort at this type of valve does not push much pressure, but seems to work. (haven't fitted to the boiler yet, so am sure Murphy will get in the way)
 
Dave
Thread: First steam test of 3 1/2" William
30/11/2011 02:11:17
Ah,
 
but the lessons are all part of the fun. Why spoil that with a bucket of cold water?
 
great milestone.
Thread: metric taps
24/11/2011 04:09:14
Terry,
 
I was shy about throwing this in - my first car as a young officer cadet at Duntroon was a '54 TF.the distributor and some of the engine bolts were this mix of metric and BSW. The doco at the time attributed it to a French influence of all things and the system was referred to as 'Nuffields mad metric'
 
Incidentally - the car also lead to many other interesting engineering questions - Why do the English drink warm beer? They keep it in Lucas fridges.
 
Dave
 
 
 
23/11/2011 03:24:56
Thanks all - best discussion of detailed issue I've read for a while
Thread: Titanium Wire
23/11/2011 03:15:31
Hi,
Not sure what length you are after, but have you tried high end bicycle spokes?Prob more expensive per foot, but you might get one second hand from a maint shop if ask, and lets you use a short length. (actually, most in my spares box seem to be 1/16 sourced from US - even though they use metric threads)
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