yes, that will work fine. That has more or less been the main way of mounting a Cox .049 since I was a kid many, many years ago. It was what was shown in all the kit plans and model magazine plans. To borrow an idea from the Goldberg Wizard, make two firewalls. One is 1/4" thick and has 4 rounded ears at each corner. Mount the engine to that with your #2 screws. Make an identical firewall either out of 1/8" or thicker plywood and glue/assemble that to the fuselage. Then you use rubber bands to hold the engine to the model by wrapping rubber bands around the ears, so the engine will give or pop off in a hard "landing" !! It really is the way to go for a trainer. Some one may have pictures posted in this section of Stunthanger to illustrate what it looks like.
  Type at you later,
  Dan McEntee

Thanks guys, both great answers. 

Screws are fine.  Just make sure that you plan for the oil soaking.  Consider giving the mount a CA bath before you fly it.  Make sure it has soaked in and set before you try the screw!  Alternatively, if the plane lives long enough you can drill out the holes and put a wood dowel in the hole then drill and screw into it.  That is what I used to do after my flying skills increased to the point that the 1/2 life of the plane was not used up by the trip to the field!

Ken

             Jim, the Skyray ALWAYS breaks it's nose off at the front of the leading edge. The engine stays on the firewall with wood screws just fine. I CA the nose  back on and it's good until the next knockout. About the 3-4 time the sensitivity calms down a bit which is good.  Essentially, where the cheek blocks stop which is the front of the leading edge. I'm not certain if they're built yet but adding some 1/64" ply or even 1/32" to both sides of the fuse and extending it back onto the wing a minimum of 1/2" works wonders.

             Jim, the Skyray ALWAYS breaks it's nose off at the front of the leading edge. The engine stays on the firewall with wood screws just fine. I CA the nose  back on and it's good until the next knockout. About the 3-4 time the sensitivity calms down a bit which is good.  Essentially, where the cheek blocks stop which is the front of the leading edge. I'm not certain if they're built yet but adding some 1/64" ply or even 1/32" to both sides of the fuse and extending it back onto the wing a minimum of 1/2" works wonders.

I’m adding 1/32 ply doublers to 1/2” past the LE. Also extending the nose 1/2” to address the balance issues with a product engine or tee dee. I figure the 1/2” nose extension on my sons will slow down the responsiveness with a babe bee and make it a suitable trainer.

Mr. Paul,

I'll remember this one!

Thanks much.

  I would be afraid of the dowels breaking off, and if you made them out of metal then breaking the ears off the back plate. Some one is making new ones from aluminum now but why break it if you don't have to. The zinc castings that the back plates on Cox engines can get pretty brittle with age. Two plywood fire walls, like used on the Goldberg Wizard, with one built into the fuselage and the engine attached with number 2 screws to the other, then rubber bands hold the two together works extremely well. All the engines mounted on the TuffBaby trainers used at Oshkosh have been crashed more times than most can imagine and we never broke a firewall or broke anything on an engine.
  Type at you later,
  Dan McEntee