Tim Wescott wrote:

Don't do this, unless you want some practical education in resonances.
At the 'bad frequency' (which was just a bit lower than what the engine
really wanted to do) I could see the cylinder moving through a 1/4" long
arc.


I remember as a kid, connecting a 049 with a three blade prop to a contraption made mostly
of wood bits and some tonka truck wheels. The engine wasn't secured very well and pulled
out the attaching screws and fell off, bounced up when the prop hit the concrete and with
that integral fuel tank, kept running. I caught it bare handed after the first bounce.

I don't recommend that. Right up their with grabbing a falling soldering iron.

Wes

Wes wrote:
Tim Wescott wrote:


Don't do this, unless you want some practical education in resonances.
At the 'bad frequency' (which was just a bit lower than what the engine
really wanted to do) I could see the cylinder moving through a 1/4" long
arc.



I remember as a kid, connecting a 049 with a three blade prop to a contraption made mostly
of wood bits and some tonka truck wheels. The engine wasn't secured very well and pulled
out the attaching screws and fell off, bounced up when the prop hit the concrete and with
that integral fuel tank, kept running. I caught it bare handed after the first bounce.

I don't recommend that. Right up their with grabbing a falling soldering iron.

Wes

I've had that happen as well but didn't bother to catch it, I just let
it run bouncing its way down the porch until the fuel ran out. Luckily
it was moving away from me.

Wes wrote:
Tim Wescott wrote:

Don't do this, unless you want some practical education in resonances.
At the 'bad frequency' (which was just a bit lower than what the engine
really wanted to do) I could see the cylinder moving through a 1/4" long
arc.


I remember as a kid, connecting a 049 with a three blade prop to a contraption made mostly
of wood bits and some tonka truck wheels. The engine wasn't secured very well and pulled
out the attaching screws and fell off, bounced up when the prop hit the concrete and with
that integral fuel tank, kept running. I caught it bare handed after the first bounce.

I don't recommend that. Right up their with grabbing a falling soldering iron.

Or putting your foot under a starter that rolled
off the bench...

David Billington wrote:

Luckily
it was moving away from me.

Unluckily, it was moving towards me....