Brief Description: Determining Engine Location for a CAD DRAWING
Way too much time, but hopefully worth it.
The engine flange (back of flange) is listed at 58 1/2" target. Bob moved this back to 56 1/2" at one point, but since builders were coming in heavy moved back to 58 1/2". Measurement is from leading edge of wing (datum line)
From the plans there is a couple of measurements that are noted. One is that THRUST CL is up 16.5" from the middle of the bottom tube (firewall). Firewall tilt back 6 degrees (top towards the tail).
Did some measurements, remeasure, little trig, and again some measurements. Despite all that measurement, I'm still calling my measurement within 3/16" total error. I'm measuring off a QB fuselage, so points should all be exact, yet over 4' you can easily fine 1/16" error... but that is a good thing that it is so small.
17.875 -- what I ended up with from the leading edge of the wing to the FRONT of the lower bottom fuselage tube. 40.625" from firewall (front edge of bottom tube) to the engine flange. Took a while getting that measurement.