On Friday, November 24, 2017 at 10:44:35 AM UTC-8, wrote:
I need to do a short test run on my ventus 2cxm engine. The fuselage is on its cobra dolley in my garage, and I can wheel it into my driveway and tie the tail to a post. I'm nervous about this, in case there is some pitfall I haven't considered. Has anyone done an engine test run like this?

It is possible to do short engine runs in your configuration ( no wings) , but never with the prop installed. Remove the prop and this will work just fine. Coolant will be running through the engine but no air through the radiator so only short runs.

If you absolutely need the prop attached, install your wings!!! Newtons Laws of action and reaction will apply and roll your fuselage.

BG