My feeling is that the vertical CG and by association the center of thrust are not critical in affecting the handling or stability. I say this because the Tri-Q adds a good 50 pounds well below the aircraft center and still handles much like the tail dragger. Also, from my experience, best to keep the flying CG closer to the front of the envelope than the rear. My 2 cents.

Cheers,

Jay Scheevel, Tri-Q2 N8WQ, 201 hours 

On Feb 9, 2022, at 7:28 PM, Ian Ashdown <ian.ashdown@...> wrote:

I bought that download too.  I’m sure it’ll be useful at some point.  What is slightly aggravating is that the parts were obviously modeled in SolidWorks, so why not offer a SolidWorks  or .stp download.  I’d have paid a little more for that, but now I just have to model the parts all over again . . . in SolidWorks!

In the end I think the design of engine mounts are going to be driven by the type of AV Mount I select ( does anyone have any recommendations) and the spacing off the firewall, driven by the balance of the lighter engine.  I’m still not sure if the effect of moving CofG a few points rearward would be a positive or a negative.  I think negative as pilot, passenger and ‘luggage’ are all aft of the CofG, it may limit the max load capacity.

Then there is the question of the ‘thrust line’. I think I’d like to raise it (from the O-200 WL position)  for better packaging, but I’m not certain yet.  Would raising the thrust line 1”- 1.6” create handling issues?  I don’t know what the aircraft vertical CofG height is, maybe it’s in some of the documentation . . .

Lots to figure out!

Ian
SoCal