On Friday, November 24, 2017 at 11:09:47 AM UTC-8, Dave Nadler wrote:
On Friday, November 24, 2017 at 2:06:20 PM UTC-5, Dave Nadler wrote:
On Friday, November 24, 2017 at 1:44:35 PM UTC-5, wrote:
...Has anyone done an engine test run like this?

I almost forgot: A well-known German manufacturer did this at the factory
last year (mighta been 2015), and trashed the new glider and trailer
bound for their USA dealer...

Can't make this stuff up!

I've seen a fuselage-only engine test at Kirchheim, they have hard points outside the shop especially for it. Been present for some engine stand runs at Williams. Quite a nice rig Rex has, using the glider's engine controller, etc. with the engine out of the glider.
I've done one run on the back of the trailer with ASH26E. Didn't take it to full power, seeing no need.
A little forward of the normal rigging position on the trailer, using the trailer ramp as a chock, since the 26 landing gear swings forward of the doors. Saw horses with a 4x4 through the spar box for torque control. Worked as planned.
But you're right to be nervous. The amount of pucker factor involved makes assembling the glider seem a better choice. While you're at it, keep the pilot current too.
Jim