Here are some things we learned in building and learning to fly our Hangar 9 Easy Fly 40, talking to others who have build Easy-fly 40s, and those helpful souls at Scenic Flyers who advised on repair of crash damage. These are some simple things you can do while building the aircraft to significantly improve its crash survivability and make assembly and maintenance easier. Most can also be done after building the plane or while repairing crash damage!
The most important modifications may be made without any recovering.
The
firewall is the weakest part of this airplane and probably most others that have tricycle
gear that attaches to the firewall. It doesn't take too hard a bump to break the
firewall. The firewall can be easily strengthened by epoxying a piece of 1/2" x
3/8" wooden tri-stock in the corner formed by the firewall and the side of the
fuselage. Refer to the photo at the top of page 38 of the manual. The
tri-stock should be as long as possible without sticking out of the bottom of the plane.
Glue the top end to the piece of plywood that hold the engine mounts.
The balsa underside of our fuselage split when the firewall broke, so I replaced it with plywood of the same thickness, making sure to glue it to the bottom edge of the firewall. This provides additional strength to the area where the front gear mounts. This requires recovering materials and an iron. This is a good time to stuff padding around the fuel tank!
The fuselage can crack
due to stress from the wings. Glue a strip of 1/2" x 3/8" tri-stock along
the entire length of each inside top side of the servo access area. Glue it to the plywood
frame, just below the top edge of the fuselage so that it does not touch the wings. I also
glued a piece of this plywood (1/32" I think) to the rectangular balsa area inside
the plywood frame. This does not have to fit closely with the plywood frame--it just
adds some stiffness to the large balsa area. I was surprised how much rigidity this
added.
The solid wooden dihedral brace (also called the wing joiner) is a weak point in this plane. Using the provided brace as a pattern, make a new one out of plywood. Drill a few small holes in each wing half mating surface. This will give the glue something to lock into.
We discovered this weakness when the wing halves separated after a hard arrival. I repaired it by drilling holes into what was left of the dihedral brace (one half each glued into each wing), and gluing in a fiberglass rod salvaged from an old fishing rod.
I also glued a strip of 1/8" plywood to the bottom of the wing halves, using a Dremel to make a hole for the aileron servo. Make sure this strip is narrow enough to fit inside the fuselage I also glued a few of strips of thin plywood (1/32" I think) about 3/4" wide by 6" long to the top of the wing half. These run perpendicular to the wing joint. Note that the plywood is more flexible in one direction than the other. Cut the strips so that they are flexible in the lengthwise direction, so that they can conform to the dihedral angle of the wing. The addition of these plywood strips required recovering. The strips are visible even after covered, but don't look bad. However, it will probably never be necessary to do this if you use a plywood joiner and drill holes as described.
Make a plywood duplicate of one of the breakaway engine mounts. Write "PATTERN" on this and set it aside. If you break an engine mount, you can use your pattern to make new ones out of plywood. I have used and crashed one pair of plywood engine mounts. The plywood is plenty strong, and exhibited cleaner breakaway characteristics than the ones provided with the plane.
Don't be concened with the front-to-back balance of the plane, at leat if it is nose-heavy. The tail of ours hang about 4 inches too high. It took about an ounce of lead under the tail to balance it. When flying, it required a lot of down-elevator trim. We removed the weight, and it still requires some down-elevator trim to fly level.
So, when placing your pattery pack and receiver, err on the nose-heavy side. It requires less weight to correct nose-heaviness. (This is because weights placed under the tail are farther from the CG and have more effect than nose weights that are closeer to the CG.) And a nose-heavy airplane will fly without problems. A tail-heavy one will not.
Replace the factory engine mounting hardware with 4-40 socket-head cap screws, available at any R/C dealer. This will make mounting the engine much easier and faster than using the provided Phillips-head hardware. Use blind nuts on the underside of the plywood that the engine mounts bolt to. Use Lock-Tite to secure the engine mounting screws.
The plastic disks on either side of the fuel tank stopper were not strong enough to prevent fuel leakage. Replace them with metal parts. If possible, use disks that are joined with a hex-head cap screw threaded into the back disk instead of a nut.
The front nose gear wire is stiff, not very springy, and tends to bend. I replaced it with a Dubro. This has one more turn in the coil spring than the original, and seems to be made out of beter metal. I can flex it quite easily by hand now. It fit without modification.
Filing a small flat place on the steering gear wire where the servo horn attaches makes it easier to get a firm slip-free connection.
I replaced the collars on the wheels and steering gear with collars with hex-key set screws. The axles for the back wheels are wide enough to put a collar on either side of the wheel. The servo horn on the steering gear has been replaced with a socket-head cap screw.
If you have trouble getting enough ground speed on takeoff in tall grass, replace the 2" nose wheel with one of the 2 1/2" rear wheels. Replace the rear wheels with new 3" wheels. In any case, larger wheels greatly improve ground handling. As a beginning flyer, I could barely keep it straight during takeoff due to lack of control and the right-thrust of the engine. After installing the larger wheels, I did a nearly perfect takeoff the first time!
Get a silicon rubber exhaust snout. Point it downward as shown in the above photo. This inexpensive little gadget will leave the plane much cleaner, and will soon pay for itself in cleaning supplies you will save!
The red model of the Easy-Fly 40 uses Goldberg Flame Red Ultracote. It can be applied with a household clothes iron. However, a proper sealing iron makes covering tasks much easier and provide neater results.
Don't worry about the additional weight of these modification. You won't notice the difference!
After a run-in with a cow, the easy-fly needed a rebuild of the front end. We converted ot to a taildragger. At first we tried a free-swiveling tail-wheel. The plane was uncontrollable on the ground. I made the tail wheel steerable by using a Gold-N-Rod to link the rudder servo to the tail wheel. While we were at it, we replaced the 8-oz fuel tank with a 14-oz, and used a standard plastic engine mount. Adding or removing washers adjust down- and right-thrust.
September 04, 2002