2slow!
I wouldn't put a saito 100 in it. I have that engine on a ultra sick 60 and it's a dream
but it would be way too heavy on the contender and too big.
do a search on "contender engine".
It flies well with a 40 and with the 60 quote:"is a guided missile".
so all it takes to make this light bird fly well would be a hot 40.
I ordered a J"EN 56 from
http://www.justengines.unseen.org/Jen.htm
took only 5 days to ship and swings a 13x6 prop at 10800.
that'll do it plenty and has the same crankcase as a 46 OS.
I"m breaking it in on the weekend.
I used CA only to build up the tail feathers. great planes pro wood glue for everthing else except
firewall and landing gear rails (30 epox)

Use Sigment or ambroid to edge glue sheeting and laminate parts.
I used quart sized freezer bags filled with sand to keep the sheeting in place.
you'll need 3-4 big clamps to hold the fuselage sides in place.
you'll also need a straight edge ( homedepot), one 11" and one 22" bar sander with a course
and fine grid (great planes).
use 400 grid to finish it.
make sure to test fit the spar with the ribs, mine where off and needed sanding to fit
the sheeting, gosh!
the razor planer robert recommended is very useful since you have to remove a lot of
balsa before you get to sand it. get extra blades.
i just finished sanding the LE ( 3 hours). got to be straight!
i'm going to ultracote the cowl in pieces, and use thinned epoxy or nitrate dope to fuel proof.
I thought about painting it too but I use the chrome ultracote for the plane and there is
no matching paint.
have fun and don't hesitate asking.
Pat