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Post by havoc on Mar 16, 2008 11:10:59 GMT
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Post by alanstepney on Mar 16, 2008 12:25:53 GMT
Edgar Westbury's 1831 was one of the first and I am sure there have been others.
Of course, all are petrol as it isnt possible to get a true diesel in model form.
(The so-called diesels that we used to run in boats and planes, and that were superceeded by glow plug engines werent suitable as they had very poor speed variation characteristics.)
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russell
Statesman
Chain driven
Posts: 762
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Post by russell on Mar 16, 2008 13:56:56 GMT
Out of interest, what is the difference between these small "diesel" engines and a true diesel?
Russell.
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cotswold
Part of the e-furniture
Still testing the water
Posts: 307
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Post by cotswold on Mar 16, 2008 14:21:52 GMT
Out of interest, what is the difference between these small "diesel" engines and a true diesel? Russell. Both use the heat generated by compression to ignite the fuel. In the true diesel fuel is introduced into the combustion chamber by an injector. In small "diesels" the fuel is taken in by a carburettor (as in a petrol or glow plug engine). Unless things have changed since my aero -modelling days of long ago, the fuel contains ether or some other highly volatile flammable liquid. |
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JohnP
Hi-poster
Posts: 186
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Post by JohnP on Mar 16, 2008 16:29:13 GMT
Roy Amsbury (or was it Amesbury?) did a Hymech in Model Engineer. He built what I think was a V8 petrol engine with hydraulic drive. Not what you'd call a beginners loco!
JohnP
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dscott
Elder Statesman
Posts: 2,438
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Post by dscott on Mar 17, 2008 13:49:35 GMT
Due to running out of paint on a garden project, painting undercover due to too much rain,
I found myself in B&Q last Sunday, where to my suprise at £59 reduced from £69 you can get a 25 cc strimmer.
Sounds good, but it is a 2 stroke hence the price drop as they are very very noisy. I heard that in some states in America they will only let you run a 4 stroke.
Shame as there was a great pile of them.
David.
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Post by havoc on Mar 17, 2008 20:31:52 GMT
I'll search in the club library for those names. Any idea of a year to narrow it down a bit?
I was indeed looking for something slightly simpler.
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Post by baggo on Mar 17, 2008 21:06:08 GMT
1831 was described in ME commencing volume 84 no.2069 - January 1941
Roy Amsbury's Hymek was described in ME commencing volume 160 no. 3827 - June 1988.
If you think the Hymek was complicated, he then went on to build a 9 cylinder baby Deltic! That was in ME commencing volume 170 No. 3942 - April 1993.
I seem to recall a petrol engined diesel outline with a hydraulic drive prior to the Hymek. I'll see if I can find it again.
There have been quite a few 'diesel' locos described over the years in ME with various methods of transmission.
I'm actually looking at scaling down 1831, or at least the power unit and drive, to build a 2½" 'diesel' loco some time in the future as I don't think it's been done in this gauge yet.
John
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Post by ChrisCrosskey on Mar 18, 2008 13:29:15 GMT
1831 was described in ME commencing volume 84 no.2069 - January 1941 Roy Amsbury's Hymek was described in ME commencing volume 160 no. 3827 - June 1988. If you think the Hymek was complicated, he then went on to build a 9 cylinder baby Deltic! That was in ME commencing volume 170 No. 3942 - April 1993. I seem to recall a petrol engined diesel outline with a hydraulic drive prior to the Hymek. I'll see if I can find it again. There have been quite a few 'diesel' locos described over the years in ME with various methods of transmission. I'm actually looking at scaling down 1831, or at least the power unit and drive, to build a 2½" 'diesel' loco some time in the future as I don't think it's been done in this gauge yet. John You might try some of the German/Japanese sites as they tend to go for the lunatic end of miniaturisation .... isn't there a guy out there building Z-guage live steam?.... A deltic in 21/2" would be fun to watch, you could probably get drawings from the guy building the big one (is it a 1:2 or 1:3 or something) good luck with getting a scale fuel injection system working though..... chrisc |
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Post by ChrisCrosskey on Mar 18, 2008 13:33:01 GMT
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Post by peterhill on Mar 18, 2008 14:23:51 GMT
The BR class 08/09 shunter would be fun with a small diesel in 7.25/7.5in gauge.
peter
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Post by mutley on Mar 18, 2008 14:37:40 GMT
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Post by baggo on Mar 18, 2008 16:39:21 GMT
A deltic in 21/2" would be fun to watch, you could probably get drawings from the guy building the big one (is it a 1:2 or 1:3 or something) good luck with getting a scale fuel injection system working though..... chrisc Hmmm, I was thinking more of a fairly simple 2 cylinder petrol engine job but, now you mention it. And I do like a challenge !  Whilst searching through ME I came across a gauge 1 diesel hydraulic using a commercial 4 stroke engine that looked quite good. It uses a miniature torque converter which seems to work well and apparently gives a very smooth drive. |
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tcase
Involved Member
Posts: 52
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Post by tcase on May 20, 2008 12:10:48 GMT
Prhaps the best multi cylinder petrol engine for a first attempt is Mastiff by L.C.Mason.
It was serialised in ME and there is a construction book probably available from Camden.
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SteveW
Elder Statesman
Posts: 1,399
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Post by SteveW on May 20, 2008 21:15:10 GMT
Guys,
If I recall correctly the model 'diesel' fuel was something like thirds of paraffin, ether and two stroke oil with a pinch of nitrate although I never found out what that was.
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abby
Statesman
Posts: 927
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Post by abby on May 20, 2008 21:26:59 GMT
Amyl nitrate !
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Post by ianengr on May 21, 2008 10:33:12 GMT
Hi Havoc,
If I understand your question correctly, you would like to replicate the Diesel-electric system locomotive in model form, if so may I suggest you look at the small 4 stroke petrol generating units produced by the likes of Honda and Yamaha. from memory these have outputs from around 300 watts and up wards in 240 V and often with a 12V aux. outlet. It may be possible to put this power through a suitable type of speed controller and motor. Some of these units use inverter technology to enable the motor to run at reduced power and speed to match the electrical load and enable greater efficiency and engine lifespan while maintaining constant AC frequency. However, whether this current could be used successfully with a speed controller and traction motor setup would need to be determined. Our learned friend 'steam4ian' would no doubt be able to give a qualified opinion on that, where as I certainly cannot.
There may also be the possibility of using the 12 V supply to power a small air compressor either "off the shelf" or of your own making that would produce sufficient quantity and pressure for an air braking system of some kind if you were so inclined ( I assume you own or know of the 12 V compressors that are sold in auto accessory stores for example.)
Another option would be a petrol motor of your own making coupled to an automotive alternator that would replace the main batteries of an existing 12 or 24 V battery electric locomotive layout with perhaps a small battery for regulation and overload capacity. I'm sure I have seen the battery electric designs in the Australian Model Engineering magazine in the past, but I,m not sure about the magazines in the UK.
food for thought.
Regards,
Ian.
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Post by havoc on May 21, 2008 17:45:27 GMT
It doesn't need to be diesel-electric, that is just one of the options. A mechanical or hydraulic drive would be fine as well. But I do insist of making it all myself. Well up to a point of course but definitely including the engine.
Those generating aren't that small! You will need 7.25" at least to hide one of those. Having 240V wouldn't be a problem, just run it into a frequency converter and drive some AC motors with it.
I have been looking at the ideas and links posted here and that Mastiff looks very nice. Has someone here the dimensions at hand? Just to check what gauge it would need.
For gauge one, one of those marine glow-plug engines would be possible but they are higher than I expected. So again a selfbuild might be better. This in case you want to put it in a prototypical case of course. And if making one myself I would like it to be a "diesel" one, with the parafin/ether/oil fuel.
Another project for "when there is time" I fear.
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dscott
Elder Statesman
Posts: 2,438
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Post by dscott on May 22, 2008 23:31:46 GMT
I started looking at an adaptation of an 08, in the shape of Diesel so I could sculpt a smug face on it, in 5". I have the wheels chassis body ladders steps etc, done, and the Mastiff pages copy from the book from the Library, inter loan from Oxford!!! All 139 pages, a chapter every lunch time.
Four cylinder horizontally opposed flat 4
3/4 x 7/8 stroke 24 cc.
lenght 8 3/4
width 7 1/2 over plugs.
Height 6 1/2.
Water cooled thermo syphon.
So far no castings, but may look into the possibility of fabrication or local foundery doing only aluminum, 5" square block cast for one of our students last week cost 40, then I had to help him mill it square.
David.
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Post by baggo on May 22, 2008 23:55:24 GMT
Hi Havoc,
Just noticed your question re Mastiff dimensions, but Dave has beaten me to it.
The layout, horizontally opposed flat four, unfortunately makes the engine rather wide and I think you would need to look at a minimum of 5" gauge to utilise it. In that gauge it may be somewhat underpowered and perhaps a vertically arranged engine of about 50cc would be better suited ? Edgar Westbury's 1831 design for 3½" gauge used a vertical twin of 30cc I think.
John
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