I have a few questions on this aircraft that I have received as a gift from a friend of mine. He had long since thrown away the plans and the manual and I am attempting to install a ST 90 as the powerplant. What is the distance that Goldberg specifies from the firewall to the engine thrustwasher? And what is the engine offset general dimensions on the firewall (to accommodate the thrust angles). The vertical "tick" marking the centerline of the engine on the firewall have long since disappeared from a previous installation.Thank you in advance for your replies!


Sincerely,
Pete

Pete
I just happen to have my old plans handy so here are some measurements:
firewall to outside of cowl or to engine thrust washer = 5.25"
thrust off set to the right is 2 degrees as per plans
the center line measured down from the top of the fuse at the firewall is 2" (looking at the fuse from the side)
the center line measured in from the right (looking at the fuse from the top) is 3.25" and 2 7/8 " from the left. This obviously
allows for the right thrust.

I used a ST 90 on my GB Extra and it was a good choice. If I remember correctly Goldberg included some wood blocks in the kit
to space the engine out from the firewall to make it fit the cowl. They measured 5/8". Alot depends on the kind of spinner you are going to use also.
Also the CG shows at the rear of the main spar for the forward spot and 3/4" behind the main spar for the rear spot.

Hope this helps
Sam

Sam, That is exactly the information I need, Thank you very much!!!!!


Sincerely,
Pete