Subject: Live Diesel-Mechanical 1/12th scale Sun Mar 17, 2013 12:38 am
Dear All,
I'm a 45 mm gauge man. I've moved up from 16mm scale. My first foray into a larger scale was my 24 mm scale George Henry DeWinton. Now I've decided to go the whole hog and switch to 12th scale. I had thought about resurrecting the old Gauge 2 (2 inch gauge), but I don't mind being a little under gauge, at least it will look narrow gauge.
A couple of years ago I bought a pull-start O.S four stroke model car engine via eBay. I'm running it in, in my test chassis. I'm running-in the the engine on a super rich setting, the garden is engulfed in the lovely castor oil smoke, I can still smell it the day after. My latest completed project was making a muffler for the exhaust, prior to that it's just a straight through pipe, and was far too noisy.
My plans are based on Dave Watkins' "Detritus". The chassis has no clutch at present, and only forward gear, it's being used to trial the required gear ratio. The primary reduction is via worm and wheel, then a spur gear reduction. These have been homemade.
This picture shows the chassis before the first test run. It has exposed universal couplings, the rear one burst apart on the first run. They are now covered without further trouble.
Here's the latest photo, with new muffler/silencer, covered UJ's, and a test giant flywheel - now removed.
1st video showing actual very first starting of the engine, camera 1
2nd video showing first run on the track, camera 2
3rd video showing new silencer/muffler, camera 1
4th video, compare the exhaust noise against that in the second video, camera 2
Best wishes,
David.
Last edited by dewintondave on Fri Jun 05, 2020 2:30 am; edited 3 times in total
Carl Hibbs Admin
Location : Haute Normandie - visitors welcome
Subject: Re: Live Diesel-Mechanical 1/12th scale Sun Mar 17, 2013 8:38 am
Welcome to the forum Dave.
Thanks for posting your project which we stumbled across on You Tube.
I'm sure there'll be a host of questions but I'll just admire the engineering for the moment.
David Grantham
Location : Midlands, England
Subject: Re: Live Diesel-Mechanical 1/12th scale Sun Mar 17, 2013 10:36 am
Wow, thanks for that. Way beyond my skills and time available but a marvellous looking piece of engineering.
GWhizz
Location : Charente, France
Subject: Re: Live Diesel-Mechanical 1/12th scale Sun Mar 17, 2013 11:13 am
I love the sound of those four strokes.
Now I know why David Grantham is so keen to pursue this engine route too!
Some wonderful engineering, areal pleasure to see
Tacbob
Location : Harz, Germany
Subject: Re: Live Diesel-Mechanical 1/12th scale Sun Mar 17, 2013 6:23 pm
Really nice piece of engeneering work. I think I'll start with the questions. What universal joints Do you use? And what's the difference to the 1st version that broke. Do you have a drawing or pic of the inner of the muffler? There are some more questions to follow.
dewintondave
Location : New Zealand
Subject: Re: Live Diesel-Mechanical 1/12th scale Mon Mar 18, 2013 5:40 am
Thank you guys. The 4-stroke is also great on fuel economy. As the engine is just idling I have found that 50 mL of fuel lasts about 25 minutes. The loco is very powerful, on the last run the leading truck derailed causing the loco to derail, but it just kept going on at its steady beat until the fuel-line was pulled off.
For the silencer, I did a bit of research into automotive silencers. First I had to order a strange metric die to cut a M9 x 0.75 thread to fit the cylinder head.
The outer shell was rolled from 0.5 mm brass sheet and silver soldered, then a central baffle plate was silver soldered in. Then the endplates, and then the bushes, and finally the drain tube.
Here's the finished silencer body, with the engine fitting and the exhaust tail pipe.
I made the universal joints. One of them failed because two of the brass pins came out by centrifugal force. To counter this I fitted the tubes over the UJ's, this measure has kept the pins in place ever since.
Best wishes, David.
Tacbob
Location : Harz, Germany
Subject: Re: Live Diesel-Mechanical 1/12th scale Mon Mar 18, 2013 6:13 am
Thank you David for your explaination. The pics don't work, so could you redo it please? Your solution for the UJ's is very simple and effective. Did you cut the M9 treat directly into the outlet chanel of the cylinder?
dewintondave
Location : New Zealand
Subject: Re: Live Diesel-Mechanical 1/12th scale Tue Mar 19, 2013 4:49 am
Tacbob wrote:
Did you cut the M9 treat directly into the outlet chanel of the cylinder?
Hi Lorenz, no this is the thread that already exists in the cylinder head. Here are the images:
Best wishes, David.
Tacbob
Location : Harz, Germany
Subject: Re: Live Diesel-Mechanical 1/12th scale Tue Mar 19, 2013 6:21 pm
Thank you David for the pics. Are the black dots on the baffle plate little holes? Is the center of the plate (the iregular shaped piece) depressed? If yes, why?
Sparkeswood
Location : Kent,England
Subject: Re: Live Diesel-Mechanical 1/12th scale Tue Mar 19, 2013 7:22 pm
I'm very impressed with your work David.I won't bother you with any questions but I love the simplicity of your design.
dewintondave
Location : New Zealand
Subject: Re: Live Diesel-Mechanical 1/12th scale Wed Mar 20, 2013 4:39 am
Tacbob wrote:
Are the black dots on the baffle plate little holes? Is the center of the plate (the iregular shaped piece) depressed? If yes, why?
Hi Lorenz, yes they are holes, the sum of their area is approx. twice that of the engines exhaust port. No, the baffle plate is quite flat. Dave.
Tacbob
Location : Harz, Germany
Subject: Re: Live Diesel-Mechanical 1/12th scale Wed Mar 20, 2013 9:32 am
Hi Dave,
Many thx for your reply. That's really interesting. I guess that you've found out while studying the real ones. What do you think, is it really necessary to do this layout in a barrel or would it be possible to do it in a scquared housing with a squared baffle plate.
I noticed your wheels are adjustable. Where did you get them?
dewintondave
Location : New Zealand
Subject: Re: Live Diesel-Mechanical 1/12th scale Thu Mar 21, 2013 5:33 am
Tacbob wrote:
What do you think, is it really necessary to do this layout in a barrel or would it be possible to do it in a scquared housing with a squared baffle plate.
I noticed your wheels are adjustable. Where did you get them?
Hi Lorenz, I'm sure a square section would work equally well. Eventually I'll build a new exhaust system with a vertical exhaust pipe exiting somewhere in the middle of the loco. The wheels are homemade, 50 mm diameter. Best wishes, Dave.
Tacbob
Location : Harz, Germany
Subject: Re: Live Diesel-Mechanical 1/12th scale Thu Mar 21, 2013 5:59 pm
Again, thanks alot Dave .
Do you already have any idea of the clutch and reverse gear arangement that you'll use?
dewintondave
Location : New Zealand
Subject: Re: Live Diesel-Mechanical 1/12th scale Fri Mar 22, 2013 6:12 am
Tacbob wrote:
Do you already have any idea of the clutch and reverse gear arangement that you'll use?
Hi Lorenz, I haven't thought much about the clutch yet. But I have a few options for reverse I'm a very slow worker. Best wishes, Dave.
Tacbob
Location : Harz, Germany
Subject: Re: Live Diesel-Mechanical 1/12th scale Fri Mar 22, 2013 12:10 pm
Slow isn't that bad . My logging truck took almost 10 years and it isn't fully finished yet. I guess my dragline will take a bit more . I don't know how long my LD loco will take. It just started .
dewintondave
Location : New Zealand
Subject: Re: Live Diesel-Mechanical 1/12th scale Sat Mar 23, 2013 7:52 am
I have bought one of these non-contact IR laser point infrared digital thermometer temp guns from our friends at ebay. Excellent service, postage free from China. I want to test the engine temperatures.
Today I had an extended run of the loco and experimented with leaning-out the engine. Normally the engine is being run at a super rich setting of needle valve open 2 turns. I leaned-out the engine until the needle valve was only open 1.5 turns. On the super rich setting the cylinder temperature was about 115 deg C, and fully leaned-out it was about 135 deg C. The cylinder head temperature was over 150 deg C. Fully leaned-out there was minimal smoke, which is most unsatisfactory Best wishes, Dave.
dewintondave
Location : New Zealand
Subject: Re: Live Diesel-Mechanical 1/12th scale Mon Mar 25, 2013 7:38 am
One other thing that came out of the run on Saturday was the abundant power of the loco. Holding the loco back by the buffer beam made the wheels slip, pressing firmly down on the loco and holding it back and the wheels still slipped. The engine didn't appear to slow down with either experiment, it just maintained its steady beat. The loco will be a great hauler. Best wishes, Dave.
Tacbob
Location : Harz, Germany
Subject: Re: Live Diesel-Mechanical 1/12th scale Mon Mar 25, 2013 8:09 am
Hi Dave,
What is the output of that engine and at what rev's? Don't know if I missed it.
dewintondave
Location : New Zealand
Subject: Re: Live Diesel-Mechanical 1/12th scale Mon Mar 25, 2013 8:53 am
Tacbob wrote:
What is the output of that engine and at what rev's?
Hi Lorenz, From the manual:
0.5bhp/17,000r.p.m.
Dave
Tacbob
Location : Harz, Germany
Subject: Re: Live Diesel-Mechanical 1/12th scale Mon Mar 25, 2013 11:00 am
dewintondave wrote:
Tacbob wrote:
What is the output of that engine and at what rev's?
Hi Lorenz, From the manual:
0.5bhp/17,000r.p.m.
Dave
Thanks Dave. And what is your gear ratio?
dewintondave
Location : New Zealand
Subject: Re: Live Diesel-Mechanical 1/12th scale Tue Mar 26, 2013 7:30 am
Tacbob wrote:
Thanks Dave. And what is your gear ratio?
It's 36:1 Lorenz. Best wishes, Dave.
Tacbob
Location : Harz, Germany
Subject: Re: Live Diesel-Mechanical 1/12th scale Tue Mar 26, 2013 11:20 am
Thank you Dave. What is the "b" in bhp standing for?
When I'm right than your loco is running with 4.45 kph or 2.76 mph real speed at full rev's. But I'm not really sure .
dewintondave
Location : New Zealand
Subject: Re: Live Diesel-Mechanical 1/12th scale Wed Mar 27, 2013 5:04 am
Tacbob wrote:
What is the "b" in bhp standing for?
Hi Lorenz, it stands for brake.
Quote :
When I'm right than your loco is running with 4.45 kph or 2.76 mph real speed at full rev's. But I'm not really sure .
Actually the upper rev limit quoted in the user manual is 22,000 rpm, so the real speed would be 5.76 kmh But I only run it at an idling speed. Best wishes, Dave.
Tacbob
Location : Harz, Germany
Subject: Re: Live Diesel-Mechanical 1/12th scale Wed Mar 27, 2013 11:14 am
Thank you Dave. Never heard of break horse power before. Is this the force needed to stall the engine? It's always good to know that one can run faster than his train, if nessassary .