"Bouncing" 2-stroke model engine

[cncjunior]

Hi Jan,
I was just on your web site and reading about your evolution in this engine. You mentioned that the engine runs for about 2 minutes or so at best. I may have misunderstood this part. When I watched your video you showed the petrol tank bubbling. I think that this indicates what the problem is. The engine sucks the petrol fumes out and through the carburetor. Looks like the tank has created a vacuum in it. Liquids will boil when under a vacuum. I haven't looked at the tank drawing itself to see if there is a small air make up vent. Like I said I may have misunderstood the problem.

Daniel

 

[AlanHaisley]

Jan,
This is a fascinating engine. One point of interest is the cycle time. I would expect this to be somehow related to the mass of the moving parts rather than their weight. It seems to me that the mass can't really be decreased since you need the weight to make the compression cycle what it is.
It could be increased while maintaining the same weight though in one of two ways: either tilt the mechanism so that a larger mass would give the same resultant weight or add a bellcrank linkage to an additional mass configured to slide horizontally on some kind of linear bearing.
This might provide a means to operate the engine slower with reliability.
I wish I could visualize a way that might make it cycle faster.
Alan Haisley

 

[Jan Ridders]

Hello Alan,
Indeed the cycle time is related (determined) by the system mass. But weight is the same as mass in the sense that weight is the gravity force on the mass, isn't it?
To be honest I don't understand the rest of your remarks, but it could be interesting anyhow if I should.

Thanks for your reacton.
Jan Ridders

 

[Rivergypsy]

Yet another lovely engine, Jan

Scooterseats - there was a guy where I used to work who built a two-stroke pogo stick, but I hadn't realised there was more than one. This was the same guy who built a mini rocket engine, which made enough power to slam a 6 foot heavy iron welding bench against the nearest wall - slightly 'eccentric'