PBT, I think you may have hit the salient point. I have been operating under the assumption (and yes, I know what assumption stands for), that for 3D stuff, the engine needs the pump. It sounds like you're telling me it doesn't need it at all. So, let me ask this...how hard is it to install a fuel pump after the fact? My definition of hard: Having to remove the fuel tank (the GP SU31 3D has some stuff in the way of the fuel tank and while I could do it, I want to avoid that if I can ). My definition of not hard: Removing the engine and then re-installing. I was planning to add the fuel pump now, during assembly, to avoid tearing things out later. But...maybe I should fly 1st without the pump and then decide? Sorry for all the ?, I simply have no experience with the fuel pumps. I've tried to find some pics, but no luck thus far. Again, I'm just trying to do this right, during the winter, while I have the time.