Hi:

    I find myself having to do this when I change engines on a profile airplane.  One can not  use a drill press as the wing seems to get in the way.  Drilling them by hand is a hit and miss proposition at best.

    Any suggestions?

                                                                                                               Tia,

               
                                                                                                               Frank

Mount your replacement engine on a 4-5mm aluminium plate and screw that to your plane. The front holes will be easy, the rear holes .... Same problem as before but the mounting holes for the plate can be spaced wider than the engine.

If you start with a plate mount you can change engines as often as you like.

G