Has anyone 1/2 scalled down...

[V 45]

Hello All,
I have plans for the Hoglet. Has anyone done this engine at 1/2 size down ?? What would be the issues doing it this way ? Reason I would like to make it smaller is size of my lathe 7 x 16, my mill is a G0704. I know it could be done on this equipment but would rather try it with what I'm comfortable with.
Thanx again...
V 45

 

[Jasonb]

I think I would go with a reduction of 6:10 rather than 1:2.

This would mean you could use a standard 1/4"x32 spark plug in place of the 10mm and the rest of the sizes don't scale down too badly for stock sizes

0.125 = 0.075 use 2mm
0.156 = 0.094 use 3/32
0.188 = 0.113 use 3mm
0.250 = 0.150 use 5/32
0.312 = 0.187 use 3/16
0.375 = 0.225 use 7/32

1.000 = 0.600 use 0.625 for the bore.

Gears would need to have the centres fiddled a bit but something like 19/38 using 48DP would get you to within 1/32"

J

 

[V 45]

Hello Jason...I would like to know why you would make the bore 0.625 rather than the 0.600 ? Thanx again for your help.
V 45

 

[Jasonb]

You can then use a standard O ring, if you went to 0.600 it would be a tight fit or you would have to make your own iron rings.

J

 

[V 45]

Thanx again Jason. Going to get ready with all this soon.
V 45

 

[V 45]

Would there be a ignition system and associted electrics when you down size this Hoglet engine? I'm going to make it 10:6 ratio smaller.
Thanx again,
Dace

 

[Jasonb]

As I said at 6:10 the 10mm plugs will scale down to standard 1/4" rimfire plugs and there is still plenty of room for the magnet and hall sensor so can't see a problem.

J

 

[V 45]

Thank you again Jason