Hello Pilots

I am going to build my first scale model this winter and i need some help
with engine size.

I have ordered Fokker D7 plans from Clevelandairline in 1/6 scale.  This
gives me a 56"Wingspan and about 8-9 lb. in weight.  This is for CL Scale
at an event in my area next year.

I want to use a four stroke Saito and i figured that a .62 would handle
this small plane with medium detail work.  Or will it?  Is the .62 to much?
Please help as i am ordering the engine from Horizon soon.  Thanks Bryan

This engine was almost used by are last champion i think.  Hope he dont mind i
used his picture for reference.  I will mount the saito as far down on the engine
barers as i can and make the fuselage sides higher to a degree to hide the top of
the engine.  Because it has to be mounted upright.  The Fokker Prop shaft is low.

Bryan, I would suggest a .91 4 stroke would be a better choice for your model. When comparing to R/C models remember that the C/L engine has to overcome all of the drag from the flying lines. On my conversions of R/C to C/L I have used the largest engine that was recommended for the R/C application, and this has worked well for me. I also like to use large diameter, low pitch props. The D-7 will have plenty of drag from the model too. For reference here are my model weights, power, and prop combinations. Profile deHavilland Hornet, 7.5#, two .30 2 cycle, 10-5 props. Sport D3A1 Val, 7.5#, .61 2 cycle, 13-5, Sport Hawker Typhoon, 15#, 1.20 4 cycle, 16-6. FAI Henschel 129, 15#, two .46 2 cycle, 12-5. Your D-7 will have more drag than any of my monoplanes. Also try a search on RCUniverse in the controlline forum for Steve Couch's SE5A and see what size engine he used (I can't remember) His model may be just a little smaller than yours.
Chuck

Scale models tend to be tail heavy, especially WW I models.  The original engines were heavy for there HP and therefore most WW I birds have short noses and long tails.  Also U-control models need the CG forward of the RC location. If you are going to use a throttle you can always cut back on power.  The scale I am flying now is converted RC.  I have a ST 90 in a 60 size ship, (GP EXTRA 300S kit).  I have gobs of power but the throttle works well.  I fly wide open only when running the smoke generator.  The point I was leading up to is that even with the oversized engine I still had to add weight to the nose to get the CG far enough forward to get her to grove.  My approach is that it is hard to get too much power and under powered leads to crashes. And if you have to add lead why not add HP instead.

PS looks like a fun project. Good Luck   

Thank You everyone i have an idea where to start now.  All of you sure have great talent.
I have seen some of your models in magazines and in internet articles maybe one day i
can fly at your guy's level or atleast be in the same event.   Bryan

Bryan, I did use Brodak paint, no toners, with a two part auto clear, (no buffing needed) I believe the name was Pro Finish Clear. One other thing, the guys and gals in C/L scale are quick to help, don't be shy about seeking help.

Blessings
Allen