The biggest single piece of advice for an aspiring Aircore owner is this:
BUILD THE WING WITH A FLAT BOTTOM!!!!
The instructions want you to use the little marks stamped into the wing to try and end up with a wing with washout. Whatever advantage you gain with the washout is more than lost with the badly bowed bottom you end up with. See how to build the wing my way below. If only U.S. Aircore would realize this they'd sell more planes and maybe bring the Cub back!
The way I build the wing is to NOT install the spar alignment strips until later.
I wish I'd taken pictures...I will when I build my Barnstormer. For now look at the pix of my CoroCap for an idea of what I did.
First, EXERCISE THE LEADING EDGE! Take the time to work the 3 folds, one at a time, on the leading edge. It's a pain to do just one at a time, but get a good yardstick and go at it...it's worth it! A hair dryer helps immensely.
Second, make 3 extra ribs per side. These will help the wing keep its shape. The middle two ribs on each side have to be cut of and notched at the back to fit around the ailerons.
Third, find the position for the forward rib halves so that the wing will fold nice and tight up over them and glue them down. You might as well put in the aileron hinges now too and let it all dry.
Forth, glue in the spar and the back rib halves making sure you keep the bottom of the wing nice and flat. To help keep the spar in position, cut up the spar alignment strips into smaller pieces and glue them alongside the spar. Go ahead and install the shear web now too.
Fifth, trial fold the top up over the ribs and spar to get the feel of it and to work the plastic a little. Slop the glue to it and fold it on over. Use phone books, catalogs, small children, or whatever you have to hold it together and flat until it dries. Let the trailing edge hang off the table a little and use lots of clothes pin to squeeze it together.
Sixth, do the other half making sure the two bottoms are not twisted in relation to each other...the spar sandwiched between the ribs should keep everything straight.
Last, finish the wing tips, add the ailerons, and glue on the center wrap.
I got this engine off of Ebay for $50. It's an O.S. FS61. Check out that muffler...it's a 280Rem. cartridge.
See the story of BigUgly on my pictures page.
Here's the mount I used to take the aerial shots on my pictures page. The camera was a Polaroid PDC640 with a Futaba S32H servo glued to the side and a servo arm pushing the button.
This is the result of my first wreck. Due to my lack of experience with depth perception I flew it into the top of a tree. A little climbing and a few minutes with a stick and down it came...nose first into a bog. A piece of duct tape on the leading edge and I would've been right back in the air except for the mud in the carb :(
My second wreck came from a moment of indecision. The O.S. 40FP had enough power to fly around with, but just not enough to maintain altitude while inverted. I did a half loop and tried to hold it at the top for awhile, realized I was starting to get too low and began the other half of the loop...only to change my mind midway after deciding that a half roll would be quicker and safer. Unfortunately HALFLOOP+HALFROLL=CABBAGE. I got another carbfull of dirt and a broken spar.
Damn! I love that Aircore! Sliced it open, epoxied in some plywood, and glued it shut again. A wreck that would've re-kitted a wooden plane only cost me a day
...and most of that time was waiting for the epoxy to cure.
The third wreck came the day after I gave up on the CoroCap. I was bored and doing stupid things. This particular stupid thing was a half outside loop from the top. I was already having a bad day and my mind wasn't all that clear...so when I realized the plane wasn't coming around I stubbornly held it and hoped I would make it...instead of just rolling out and yanking it upright. At least I had the presence of mind to go full-up at the last second thereby saving the wing and most of the fuselage. It just split the nose a little and broke the Power Cartridge. It took about three hours to fix everything. Good Aircore, nice Aircore!
This is my workhorse. You can see the repair on the starboard wing from wreck #1. This picture also has BigUgly up front.
My CoroCap was my attempt at a durable aerobatic trainer. Durable...what a laugh! Here's a bit of free knowledge for aspiring R/C aircraft designers:
1/4" Birch plywood is not as strong as it looks.
The construction was fairly simple. A profile fuselage with coroplast tailfeathers. The wing was 4mm coroplast with a Cap 232 airfoil.
These two pictures show the results of fairly minor take-off incidents. Regular stick-built planes might have bent a linkage or popped a rubber band or two, but that birch plywood just snapped like a pretzel. Sadly, this plane never flew (well, it flew about 15 ft. but the ailerons were much too sensitive) and after the nose came off I decided it would make better firewood than an airplane. The wing however, will come back as something else.
Here are a few more Aircore tips:
Don't use APC props until you can land well...the APC props are stronger than the Power Cartridge...buy a 6-pack of Top Flight wooden props and break them first.
Don't use the plastic tubing supplied for the fuel tank stopper. Because the tank sits halfway through the PC they'll probably crack and let air in about halfway through a tank of fuel and kill the engine.
After your first few landings start using nylon bolts to hold on the main gear. This will let you turn harder on the ground without dragging a wing tip and breaking an aileron linkage.
Mount the wing like you're going to fly. Now glue a couple of strips of 4mm coroplast to the bottom of the wing at the root up against the fuselage. This helps two ways, first it makes lining up the wing quicker when you put it together, second it helps keep the wing from twisting and breaking and aileron linkage every time you drag a wing tip.
If you twist the wing far enough for the rubber bands to slip off the center wrap they will cut right into the wing. To help prevent this wrap a little piece of 2mm coroplast around the leading edge of the wing just outboard of the big center wrap.
Add a squirt or two of ArmourAll to your new gallon of glow fuel to cut down on foaming. With the hard mounting of the fuel tank this is a problem on the AirCore.
The blue stripes on the bottom of the wing make the plane very dark on a cloudy day. I repainted the stripes with orange Rustoleum and it helped tremendously.
Don't use 3" wheels unless you really have to. I couldn't believe how much up elevator I had to add in when I tried this...there wasn't much left over to go "up" with.
My receiver is Velcroed to the vertical surface right behind the front window. This gives easy access to plug in the wing servo and is also a very safe and soft place when you wreck.
As an aesthetic touch, paint the wing dowels.
Another aesthetic touch, paint the Power Cartridge.
