I'm building a cross country plane and need help with selecting a proper wing.

The lower the drag the better. I'm thinking something like a trainer wing (probably higher drag), because of dihedral and self leveling properties. This makes it much easier to fly the long distance (100 miles). I know there probably isn't the perfect wing with everything I want, I will need to compromise in some areas.

I'm thinking a wing in the 60" wing length, and maybe 11" to 12" cord depth. My questions are do I gain anything by shortening the wing and increasing cord? Is there less drag by lengthening the wing and decreasing the cord. Is a flat bottom the best way to go.

I'm guessing this will end up being a 6-7 pound airplane, with 90 oz of fuel on board. Haven't decided on motor yet, will either be a Supertigre .75 or maybe a Saito 100. Depends on which one would be more fuel efficient.

I would suggest you go with something more like a sailplane wing. A little longer aspect ratio will give you better fuel economy. Look at Eppler airfoils and others used for sailplanes as well. They tend to have good penetration and high lift/drag ratios. Other than that I can't make any specific recommendations, but someone here who knows more than I do will certainly be able to.

Look at the Selig 3021, and a 8-10:1 aspect ratio.
No ailerons, for a clean wing surface.
Dihedral/ployhedral for stability.
A 4-stroke is much more fuel efficient than a 2-stroke.
With 90 oz of fuel, you should get much more than 100 miles!
The California Marathon planes on 64 oz. fly for 8 hours plus, 300 miles plus!

What size engine's are they running? And what size plane?

Here's the California Marathon site link:
http://www.camarathon.com
The airplanes can be anything.. from simple ARFs to sophisticated one-off special purpose designs for the event.
Motors can be any type... usually 4-strokes. Some highly modified, others stock.
I flew in the Sportsman class some years ago with a purpose designed plane and an OS 26 4-s. 50 miles in about an hour, on about 11 oz of fuel. The winner used about 6 oz. (gee, that's a long time ago..)
I ginned up another for last year's electric event, but burned up too much equipment testing...

We would need a little bigger motor, as we travel up to 65 MPH. We use 40 to 60 size planes and .70 to .90 four strokes and almost always use 70 to 90 oz. of fuel. We must be doing somthing wrong.

Just had a thought, CA is very close to sea level where you are flying? We are at 4000 feet. Air is thinner, less oxygen. Must be why we need more fuel, 'spose it effects wing loading? I'm trying to put into perspective the aspect ratio you mentioned earlier. Would a 10:1 wing figure out to be a wing measuring 60" X 6" ?

i just read the rules. 9:1 and over is powered sailplane class. I would go with 8.9:1 to get the most out of it. Build accurately.

There's Rules?

yeah... sucks, doesn't it? You could easily win if you had some type of air-to-air missiles and wiped out the competition. Actually, there's nothing in the rules that sez you can't.

The reason my .26 powered plane used so much fuel was I had the guys driving at 65 mph for most of the 50 mile lap, instead of a more logical 40 or so, which the more experienced guys did.
At that speed I expect I'd have used maybe 6 oz.
Used a 9x4 prop.
On a Kadet Senior (which shows up winning at the Ca. Marathon way too often) 65 mph is easy with an OS 70, and little fuel consumption.
The marathon event at Baker runs from a lakebed next to the freeway up about 2000 feet over a mountain which is something over 4000' then down about 1000 feet and return..
Engine power doesn't change much.
I'd made up a position indicator repeater to watch while flying, with throttle position and elevator position calibrated for speed for my next atttempt which hasn't happened yet.

Tall Paul - I didn't see anything that had a max or min size for the plane - just fuel quantity. I'll bet if you designed a plane right, you could get an O.S. .26 4-stroke to carry 32 oz of fuel which should give you some long flights. But then it might be so slow that it is counter-productive. I guess the secret is finding a system that gives the best balance of speed to fuel consumption. Too bad I live on the wrong side of the country. I'd like to give this one a shot to see how I do.

I was thinking of starting with the wing, less drag the better.

What you want is the least amount of fuselage cross-sectional area to contain what it has to carry.
For a slimer, that's the fuel tank. Find a long slim one.
The wing should be high-aspect ratio, semi-symmetrical, for a lower pitching moment. Lift comes from flight speed as well as wing area.
This electric weighs 3-1/2# empty. Intended to carry 3 sets of 10x3000 NiMh batteries, which weigh 69 oz. total.
A half-gallon of fuel takes about the same cross-sectional area with a long tank.
With 1324 in^2 on the wing, loading is a decent 9 #/ft^2. AR is 7.55 on 100 inch span.
Airfoil is an S7035, about 10% thick.
With a glow motor and that much gas it would be an all-day flier.
The controls are tuned for level flight and gentle turns. It is NOT an aerobat! And will never be flown as one.
Something to keep in mind.

I would suggest that at that speed you will be flying with quite a high reynolds number and a very low lift coefficient. A slope racer or F3B airfoil would do well on such a model. But then so would the Selig 3021 which is MUCH easier to build accuratley if you are doing a built up balsa wing. But take a hint from Dr Selig himself and extend the top sheeting back to the 60% chord mark to better support the covering through the tighter parts of the upper surface curve. The spars would still be at the max thickness point and the preffered structure would still be D tube but there would be some additional sheeting behind the top spar back to the 60% point. You'll have less drag that way and better slow speed performance for takeoffs and landings.