Greetings,
I'm putting this World Models Ultimate together and I'm wondering if I need to have any incidence on the top wing? It's not mentioned anywhere in the manual, but I'm sure I've read somewhere to put some positive or negative incidence on it......I can't find it again!! Any suggestions? What's the idea behind having different incidence on the top wing anyway?

From my experience with biplanes, I always started with 0. I had a 1/3 christian eagle that worked best with 1 degree neg. It penetrated the air better in landings. I,m building DP's ultimate now, its wings are 0, but the tail has 1.5 (not sure which way, book is in the garage). I know someone to call, If I find anything out I'll post it. Sorry I couldn't do more.

I can't speak for the world models version.
My Global Ultimate ARF recommended 0 to -1 on the top wing...with the bottom and stabilizer being equal (0).

I started out with Negative one...
I kept pulling it up to eventually reach zero.

Mine flies best with zero on all three surfaces (stab, bottom wing, and top wing).

Negative incedince in the top wing causes it to stall after the lower wing. The lower wing is at a greater angle of attack and therefore stalls just ahead of the top one. The plane just seems to mush a bit foreward. My Goldberg is set at 0 for both wings and +2 on the tail. If you're going to set it for negative incidence be sure there isn't a warp due to the shim. You need to be sure the incidence in set in the center at the cabane and at mid panel at the interplane struts. This way it's nice and flat.

I got a Global Ultimate and was reading the manual before I build. Haven't picked an emgine for it yet but would like to know if I have to check the incidence. The manual said to check and set at 0. I want to be sure I have to before I buy a meter. I've been flying for three years now and never had to use an incidence meter. This is my first bipe, will I need one again?

You'll need the incidence meter with the Global Ultimate. You'll never get that upper wing on right without it or some method of checking all the incidences. Mine flys good with the wing at -.5deg.
Stalls are straight ahead and clean.

MBonk
With an ultimate I would start out with zero all around (tail, lower and upper wing).

Generally most bipes are positive stagger with no or minor sweep. For these planes upper wing incidence effects the stall and trim characteristics in the following manner. Positive incidence results in a nose downmoment with stall and negative incidence biases toward a pitch up in stall. I try to set the incidence to minimize trim change with speed. That's why I like to start with zero all around and adjust from there for aerobatic planes and not worry about stall unless it's ugly.

How hard is the meter to use? I've never used one and don't anyone in my club has. Do you only need them for bipes?

Using an incidence meter such as the Robart is pretty straightforward. Just secure the airplane in a level configuration (using the built in level and gauge) you then simply slide the meter's calipers together over the leading and trailing edges of the wing or stabilizer and note the indication on the needle. Generally when setting up a biplane, start on the lower wing, and then do the top. The robart meter costs about 38.00, which is cheap insurance against awkward snap/stall situations, and generally poor performance due to poorly set up decalage. It is pretty tough too. . so you will have it for a long time!

Best of luck,
Brett

I have found on almost all the Bi Planes I have built that 0 on the wings is what you want. BUT to counter the climbing tendency of the added lift on a bi plane you add some positive for the horizontal stab. AS was stated earlier the Goldbergs show 0 w a +2 for the stab.

The DiBo