Classic Remote Control Airplanes Kits Reviews – Tower Kaos 40
by Trinidad Costales
- Wing Span: 55 in (140 cm)
- Wing Area: 566 sq in (3652 cm²)
- Length: 49.5 in (126 cm)
- Weight: 5.25 lbs (2.4 kg)
- .40 – .46 2 – stroke
- (6.5 cc – 7.5 cc 2 – stroke)
- .48 to .70 4 – stroke
- (7.8 cc – 11.5 4 – stroke)
- 4 Servos required
The Tower Kaos is a new kit version of the classic Joe Bridi Kaos design for a sport pattern plane. This is a low wing monoplane with a very thick symmetrical airfoil for four-channel radio control. The Kaos and its variants are generally .60-sized aircraft while this kit is perfect for the popular .46 2 – strokes. The plans are drawn showing both this type engine and the OS .70 4 – stroke. The all-wood kit is well packaged with rolled plans, bagged hardware, canopy, and an excellent 64-page instruction manual. All instructions are clear and complete with lots of tips on specific techniques suggested. The die cutting, parts fit, and quality of wood were excellent. A lot of the parts fit with a snug slip fit that held the alignment while glue was applied. This kit was built in the fall of ‘98 and flown regularly through 1999. It is still in very good shape.
The tail surfaces are built first of die cut 1/4″ balsa parts. The long pieces forming the surfaces are capped at the tips with pieces having the grain running on the perpendicular, which prevent the surfaces from warping under the tension of the covering. This adds slightly to the parts count but the resulting true flying surfaces are worth it! The elevator halves are joined with quite a heavy U-shaped wire that was replaced with a much lighter 1/4″ dowel.
The wings are built over the plans using a provided tapered trailing edge jig. The construction is the standard rib and spar “D” tube. The lower spar is pinned flat to the board and the trailing edge pinned to the jig. This method is preferred over the rib tabs often used. When the upper spar, shear webs, and leading edge sheeting were being added, a four-foot level was laid across the ribs to help keep things straight. The wings built straight and true. Tower uses a novel method of machining the leading and trailing edge pieces as a unit greatly reducing the builder’s effort. The wings are sheeted from the spar forward with 3/32″ balsa and the spar is fully webbed with precut 3/32″ pieces. The thicker sheeting is a lot tougher than light 1/16″ balsa normally used and can be sanded down to look nice. The wings are stiff and strong and light in weight thanks to the light material provided.
The small dihedral angle specified, 1″ under each tip, seems perfect. Torque rods are provided for use with a single aileron servo. Short pieces of trailing edge stock were provided with slots precut for the torque rods. The preshaped solid balsa ailerons are a time saver. After joining the wings with a plywood dihedral brace the center joint is reinforced with 3″ fiberglass tape, which is not provided. The glassing was done with polyester resin. This may not be the lightest method but is strong.
The Kaos fuselage is basically a box of the modern self-aligning lite-ply construction that is completely covered with balsa sheeting. The thrust angles are built in when installing the firewall. The plane is designed for an upright engine installation with the engine partially enclosed by the fuselage. This is appropriate for a sport plane but the engine was mounted horizontally and balsa scrap was used to fill in around the engine and muffler for better appearance. The recommended Great Planes adjustable engine mount can carry the nose gear while mounted either way.
Pushrod tubes are built in during the fuselage construction. The long steel pushrods and tubes were replaced with 1/4″ dowels to save a bit of weight. After rounding the corners of the fuselage and sanding it smooth it is still pretty boxy and this may be the one complaint with this plane.
I deviated from the sequence of instructions unnecessarily! Because I wanted to wait until the very end to locate the servos for proper balancing, things became more redundant and time consuming. In the end my servo location was the same as shown on the plans.
Tower uses a really cool method to mount the wings to the fuselage. After sanding the fuselage sides to match the wings you insert the 1/4″ dowels almost all the way into the wing so they just hold a partial former. Then the wing with partial former attached is centered in the fuselage and the partial former is tack glued to the former in front of the wing. Then the wing is removed and the partial former thoroughly glued in place. Foolproof and easy. The stabilizer sits on top of the fuselage and the vertical fin mounts on top of the stabilizer. Both are reinforced with 3/8″ triangle stock. Hinges are not provided, I used Sig Easyhinges on all the surfaces.
The Kaos was covered with bright yellow and metallic teal Monokote. The top is mostly yellow with some contrasting teal stripes. The underside is all teal with a large checkerboard pattern on the outer halves of the wings. The design has provided excellent high visibility with good contrast between top and bottom. We normally have a mountain behind the airplane on final approach so I make the leading edges a bright color (in this case yellow). Keep this in mind if you’re landing in front of trees or other dark colored background.
An 8 or 10 ounce fuel tank is inserted forward from the wing opening so fuel line access isn’t good. You might want to replace the provided wire throttle linkage with one of the flex cables. I used the wire in its plastic tube and it works fine. My engine is a well used Enya SS.45 two stroke with a Slimline Pitts style muffler that’s very loud. Propeller is the APC 11×6. The yellow Dubro 2 1/4″ spinner seems to match the Monokote perfectly. The canopy was glued on with RC56. A small cavity was carved out of the left wingtip and filled with lead shot and shoe goo for the lateral balance, then patched with Monokote. I was happy to find the finished weight (5 1/4 lb.) a quarter pound under advertised weight.
Flight tests showed the specified C.G. (a bit nose heavy) and control throws to provide lots of stability and smooth handling. Over time, the balance point has been shifted back a bit and the control throws have been increased. This airplane excels at pattern type aerobatics with precision being the strong point as opposed to the “3D” or fun-fly type gyrations. There is very little control coupling and the plane maintains a heading well. Inverted flight is equal to upright with a bit of elevator held. Knife-edge flight requires very little correction, just tip it up and hold the rudder. The Enya pulls the Kaos over 300 foot loops without wavers. The first hammerhead that was attempted with this plane looked nearly perfect. Stall speed is very low; the plane drops the nose a bit without veering then continues flying. The thick wing, 18.75%, is very forgiving at low speeds and simply will not go very fast helping to maintain a steady speed through vertical maneuvers. After finally stalling, a spin starts with full rudder and some aileron and stops as soon as controls are neutralized. On landing approach, two or three clicks of up elevator trim are dialed in and throttle is reduced. This really slows the Kaos down then the final approach is made at idle and it just settles in.
The local field is mostly cobblestones with thin grass and while the tricycle gear was holding up well, the decision was made to convert to taildragger before damaging the wings. The Kaos has been crashed twice through stupid arrogance, with only minor and easily repaired damage. One crash destroyed the spinner and engine mount without damaging the firewall or engine! The Kaos was back in the air the following weekend.
This was my second powered plane following a typical .40 size, high-winged trainer. I have flown a lot of slope gliders, though, and brought aerobatic experience with me to the powered planes. Anyone comfortable with a Four Star .40 would have no problems with it. This could be a person’s second airplane with the first flights on a trainer cord. I am practicing the beginners’ IMAC sequence with it. The Kaos seems perfect for learning aerobatics, inspiring confidence and going exactly where you point it. I have not begun to see how snappy it can be set up because it seems built for long, smooth maneuvers.
A trainer sacrifices maneuverability for stability while a fun-fly plane sacrifices stability for quick handling. If there is a golden mean where agility and stability are balanced, the Kaos may define it. It has been a favorite airplane of many flyers for a couple of decades. The Tower kit is well designed and the materials are good. It is low priced, quick to build, light and sturdy. It is a plane to run lots of fuel through while becoming an expert pilot.