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?

The fuselage may try to roll in the trailer cradle. Stabilize it so it can not do roll. Best and safest way is to install the wings for weight and stability.
Tom
Boise, ID



On Friday, November 24, 2017 at 11:44:35 AM UTC-7, 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?

On Friday, November 24, 2017 at 1:44:35 PM UTC-5, wrote:
> ...Has anyone done an engine test run like this?

Yes, and broken their canopy, run prop into trailer top, and
other very interesting outcomes.
Watch YouTube "Deep Fried Turkey Fire" instead;
just as entertaining and much less expensive.

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!

At 19:09 24 November 2017, 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!

Don't do it! I used to do this with a DG400 but I had a proper
substantial steel frame to hold the fuselage (it anchored via
the wing pins). Even with this system the whole procedure felt
very unsafe, especially at full throttle; it also took far longer
than driving to the airfield and rigging the glider properly.
Dave W
>

Don't do it!

/Users/randyteel/Desktop/DG 1001/1992-02-e Engine Test Run.pdf

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

Don't do it! From DG...Never test run the engine without the wings assembled to the fuselage. Due to the engine torque the fuselage will tilt the with higher engine speed and roll to the front. "Mortal Danger"

On Friday, November 24, 2017 at 2:50:52 PM UTC-5, JS wrote:
> 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

Right, SH was not the manufacturer I mentioned above ;-)
Though I can think of some of their customers who've damaged
their plane/motor trying what the OP suggests...

On Friday, November 24, 2017 at 1:44:35 PM UTC-5, 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?

I have done winterising warm up runs many times like this, with a 2x4 through the
spar box on saw horses; then I spray preservation oil into the Rotax carbs;
as it is an M you have throttle control; stay away from full power.

John F

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?

Congratulations you are already part of the way there by posting about doing this online. You know this is not a good idea, asking for advice to try to make it a slightly less bad idea is not good. But if you do it please make sure you have somebody video this who is able to post the video of any accident on YouTube.

I've done and seen a lots of ground runs. Either in a professional built heavy duty steel engine stand (Williams Soaring) or with rigging the damn glider. If the later, tie the tail down to a heavy object like a pickup truck with nylon tow straps. Don't dick around with damaging expensive toys or risking people's lives.

I've also seen the aftermath of people walking into light aircraft propellors, which makes me awfully nervous about doing stuff like this.

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?

I've done it a few times, but you do need to think through the consequences.. I tied the tail off to something that wouldn't move, put some lumber through the spar box resting firmly on saw horses, and kept clear of the prop. Nothing bad happened and it didn't seem terribly dangerous. Once I did it with the tail tied to a stake in the ground and that wasn't immovable enough, so now I tie it to the truck or the forklift - both about 8000 lbs.

If you aren't completely sure about what you are doing, best to rig it.

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

On Saturday, November 25, 2017 at 9:06:48 AM UTC-8, BG wrote:
> 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

I would NEVER run the engine w/o the prop - it has no load and will over-rev. Using saw horses and tying down the tail will work safely. I don't bother with the saw horses if I am only going to run it at a fast idle, which I did yesterday. The dolly and glider are on the back of the trailer. I run the engine (ASH26E) once a month to lubricate it. The test stand Rex has requires removing the engine from the glider - rigging the glider would be easier. Don't run it in your garage, however!

Tom

On Saturday, December 2, 2017 at 11:08:41 PM UTC-6, 2G wrote:
> On Saturday, November 25, 2017 at 9:06:48 AM UTC-8, BG wrote:
> > 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
>
> I would NEVER run the engine w/o the prop - it has no load and will over-rev. Using saw horses and tying down the tail will work safely. I don't bother with the saw horses if I am only going to run it at a fast idle, which I did yesterday. The dolly and glider are on the back of the trailer. I run the engine (ASH26E) once a month to lubricate it. The test stand Rex has requires removing the engine from the glider - rigging the glider would be easier. Don't run it in your garage, however!
>
> Tom

I'm looking at making a test stand, perhaps with a small dyno, to test a Hirth F10A engine for an ASK-14. I don't want to fine-tune the linkages on the 4 carbs inches away from a spinning prop. But I plan to do something more substantial than this:
https://www.youtube.com/watch?v=L8mwZBY4O1g
which is downright scary.

On Sunday, December 3, 2017 at 7:23:09 PM UTC-8, wrote:

>
> I'm looking at making a test stand, perhaps with a small dyno, to test a Hirth F10A engine for an ASK-14. I don't want to fine-tune the linkages on the 4 carbs inches away from a spinning prop. But I plan to do something more substantial than this:
> https://www.youtube.com/watch?v=L8mwZBY4O1g
> which is downright scary.

Depending on configuration, might be easier to make a guard to go between you and the prop. Tip proof base with verticals to support wire fence material barrier or similar. You stand on part of the base so your weight adds to base stability. The guard must make it physically impossible to inadvertently fall into or contact the prop.