2-cylinder Gamma engines

[Chriske]

Hi guys,

This is what my pupils made over the last months.

http://gti-duffel.be/4B/StirlingCD-2cil ... er-loc.mpg

It is the same loc as last year(owne design) except this time we made a 2-cylinder version.
Same procedure, my pupils made all the parts and I did the assembling of the locs (at home).
This movie is taken during actual maidenrun of the engine, I was very pleased it got that fast during its first run. It had not even ran in.... a wopping 1000 rpm..!
To finish this one I have to mount the wheels as it will run during open-door may next on track 'gauge 1'
In the background of the movie you'll notice a second engine (almost done). That second one is a fixed engine and will be used to drive a 8' diameter ferris wheel (will also be made by my pupils, that's the idea...)

Chris & crew
GTI-Duffel (Belgium)

[Ian S C]

Good one crew, and Chris, Have you tryed just lighting up one side, and see what happens to the other side, you might want to put a heat barrier between the two hot ends, with any luck you should get a temperature drop. Ian S C

[Chriske]

Ok guys,

The first engine is running, the second one is almost done. They're identical. This second will be used to drive a ferris wheel.
Key question is : will this work...?
This 2 cylinder runs at 1000+ rpm, the ferris wheel will make one revolution every 1 or maybe 2 minutes (maybe even slower). Will this engine have enough power..?
The first part of the speed reduction will be done with chain-wheels the last reduction will be done with worm/worm-wheel.
Diameter of the wheel is 2 meter (about 7 feet)
Drawing not yet finished.

[Ian S C]

Chris, I don't think you'll have any problem with the ferris wheel, as long as the bearings are OK, and it is reasonably balanced. My no 2 motor, when attached to a winch(can't remember the reduction ratio)will pull two 20L containers of water across rough ground, and it has raised a 50Kg bit of railway track 3M in my workshop, all without reducing engine speed by any great amount. The stove top motor in my gallery is able to turn a 30" fan ( the fan was made for experiments with a wind power generator). Ian S C

[Chriske]

Ian,

The two large bearings are brand-new. I will remove both sealings from the bearings(the caps to hold the grease and avoid dirt entering the bearing, don't know the correct English name) I will also remove the original grease and replace it with a shot of WD40. I will do the same with all other bearings in the 'gearbox-section'. And indeed I was planning to balance the wheel thoroughly. 'Last minute-balancing' will be done with little dolls placed in the ferris-wheel capsules. Some kindergarten will lend us about 250 Playmobil human figure toys to fill our capsules. These figures are about 3" inch high, the perfect height for our wheel...;-)

Chris

[Ian S C]

Some bearings have shields, which are metal covers, and others have seals that are flexable, these are the ones that cause friction, but all are best removed. Use a lioght oil, sewing machine oil, or an oil we have here in NZ, and I think they have in UK called 3 in 1 oil. WD- 40 and similar products form a thick coating on the metal parts when the light fluid evaporates. There is also one I would like to try, it's called Super- Lub, it's a Teflon lubricant, it comes in a number of forms, aerosol spray, a liquid, and a grease.
The way things go, you could proberbly build the whole wheel from Leggo. Ian S C

[Ante]

Hi Criske!

I think you should avoid worm reducer, it consumes lots of power (efficiency about 30%)
I know that is simpler with worm because one stage can have reduction ratio about 1:100
But spur gears are much more efficient. Try with old oven they have small gear motor with gear ratio about 250 (for chicken roasting)

My motor could not rotate modified gearbox of wipers without load


Salute!
Ante

[Chriske]

A planetary gear system could also be a solution.

[Ian S C]

Proberbly the only realistic method of the great speed reduction required is a well designed worm, proberbly using a good polished worm, and nylon worm wheel. If you cut your own worm wheel, you can use a large tap as a hob, and you don't have to worry too much about little things like the number of teeth on the gear, if it's a few more or less than what you desided, you'r not making a clock, and the worm is just a bit of steel with the same thread. The worm wheel could also be bronze, I'm just looking at the cheaper way, The nylon must be OK, look at the windscreen wiper motor in a car, I use one of those for the power feed on my milling machine, and 10 or 12 years on, and its still going.
I think I'd use a belt drive for the final drive to the wheel, it can be slipped off if you need to turn the wheel, because thats the main drawback with a worm drive.
Maybe if you find an old wiper motor, or motor for a car window opener, or some types of cake mixer, you could salvage the worm and wheel from there, it'll be some where between 100 and 150:1 reduction.
Ian S C

[Chriske]

to solve a few problems a youtube link :
sorry for the inconvenience...

http://www.youtube.com/watch?v=tVInE4VCDX4