Slow Motion
Bill Evans
The Slow Motion Tradition is the fourth in the series of Slow Motions.
First was the Slow Motion (for .15–.40 engines) in the January 1987 Model Aviation. Second was the Senior Slow Motion (.40–.60 engines) in October 1993 MA. Third was the Slow Motion TD .09 (for .09–.15 engines) in August 1997 MA. All Slow Motions are of the 21st-century Simitar Series.
This model was so named because it is a Slow Motion elevated tricycle gear and stretched fuselage with enhancements to give it a more traditional appearance. Almost everyone who has seen the new Tradition has taken a great liking to it.
Construction
Wing
- If you do not cut foam, you may order cores for the Tradition from Soaring Research, 454 Wildrose Ln, Bishop CA 93514; Tel.: (760) 873-4932. Cost of wing cores is $22 plus $8 for shipping.
- Be sure the wing panels are flat and straight; use weights with the core on a flat surface if necessary.
- Cement the 1/4" balsa leading edge undercaps to the leading edges and the 1/4" balsa trailing edge spars to the trailing edges. Adhesive should be user-friendly odorless cyanoacrylate (CyA) or carpenter's glue; do not use regular CyA on foam. Set these aside to dry until after the fuselage is constructed.
- Plane and sand the 1/4" leading edge undercaps and trailing edge spars so that the sheeting will fit over them. Do not sand any of the core away.
Sheet the wings using Corefilm to apply the 1/16" sheeting to the leading edges, trailing edges, and center section. Sand the leading-edge sheeting flush to the undercap and then pin and cement the 1/4" x 1" leading edge cap to the leading edge. Apply 1/16" x 1/4" capstrips on two-inch centers from the end of the inboard sheeting to the tip of the wing.
Shape and sand the leading edge. The leading-edge bottom is nearly flat and the top curve is fairly steep. Do not round the leading edge; a maximum radius of 1/16" is desirable. Attach the wingtips; carve and sand to airfoil shape. Finish-sand the wing panels and join them with five-minute epoxy.
Fit the elevons to the wing. Use X-Hinges to attach the elevons. If you use mechanical elevon mixing, form and install the elevon control rods before you attach the elevons. Cut and cement end-grain balsa into the wing at the bolt locations to prevent crush of the wing when bolting it to the fuselage. Fit the 1/4" plywood wing plate into the leading edge of the wing at the center section. Set the wing and wing plate into place on the fuselage and check for fit before gluing the wing plate to the wing.
Using waxed or greased temporary 1/4" dowels, set the wing and plate into place, align them, and glue the plate to the wing with five-minute epoxy.
Place hardwood gear blocks at the correct location on the bottom of the wing, mark the area, and remove the sheeting and foam so that the blocks are flush with the sheeted bottom wing surface. Glue these in place with five-minute epoxy.
Sand and cover the wing. If you use electronic elevon mixing, install 1/8" plywood servo plates flush with the bottom surface of the wing and dig out the foam for the servo pocket prior to covering the wing bottom.
Fuselage
- Cut the fuselage pieces; place and pin the fuselage top piece on a flat work surface. Place the side pieces alongside and mark the location of the firewall and bulkhead on the top and sides.
- Pin the 1/4" square longerons in place 1/4" from the edge (use the sides as a guide). Curve these longerons from a three-inch fuselage width at the wing/elevon hinge location to the centerline of the fuselage at the tail. Glue in place by applying thin CyA to the inside edge of the longerons (the CyA will run under the longerons).
- Pin the fuselage side to the fuselage top; pin the firewall and former in place against the top and side; CyA the side to the top, firewall, and former. Be sure to curve the side to the center at the rear. Pin and glue the second side into place; pin and CyA the 1/4" square bottom longerons into place against the fuselage sides. Pin and glue 1/4" square strips around the back side of the firewall.
- Sand the bottom edges of the fuselage sides flush with the bottom longerons. Pin and glue the front fuselage bottom into place. Pin and glue the 1/4" balsa fuselage bottom rear into place. Round the corners per the plan and sand the fuselage as needed.
Complete and sand the vertical fin (and rudder, if desired, for aerobatics). If you are using a rudder, attach it, sand and cover. Cover the wing and fuselage; epoxy the vertical fin to the fuselage.
For final fit: set the wing and plate into place, align and glue as described above, install landing gear blocks and servo plates as needed, and sand and cover all surfaces.
Control Surfaces and Mixing
A Simitar requires only pitch (elevator) and roll (aileron) functions for stable flight. Except for Pattern flying, a rudder is not required.
Simitar control surfaces are elevons, which serve as both ailerons and elevators. Consider the control surfaces as full-strip ailerons that counteract to provide aileron control and actuate simultaneously to provide elevator control. This requires mixing, which can be mechanical or electronic.
The best mechanical method is the sliding tray:
- One servo in the tray is set up for strip ailerons.
- The second servo is for elevator; its control arm is attached to the stationary bulkhead at the front of the tray so that it will slide the tray fore and aft to provide the elevator function.
Electronic mixing can be provided by a radio with built-in mixing or by using external mixers such as Ace's Christy Mixer or the Quillan Mixer, which plug in between the servos and the receiver (both $25–$45). Some newer radios have built-in elevon or flaperon mixing (examples used: Futaba 6VA, 7NFK, 7UAF, 7UAFS, 7UAP, and 9VP).
Sliding Tray Setup
- The sliding tray fore-and-aft formers are 1/4" plywood. Drill the 1/8" holes for the dowel through both formers at the same time to keep the holes parallel.
- Cut the 1/8" plywood tray to fit the aileron and elevator servos.
- Push the dowels into one of the formers. Slide the red outer Nyrod over each dowel, then push the other former onto the dowels.
- Cement the tray in place onto the Nyrods (be careful not to get cement inside) and install the servos as usual.
Electronic Mixer Control Setup
- Use 1/8" plywood trays to mount the servos in the wing; epoxy the trays flush on the bottom of the wing after sheeting.
- Grind a hole in the top center of the wing and use a piece of piano wire with a hook bent on one end to tunnel out for each servo lead. The lead is then easily fished through with a piece of string.
Final assembly:
- Install the landing gear, engine, fuel tank, and radio. Hook up all controls and check to make sure there is no binding.
- Check the aircraft balance: the center of gravity (CG) is approximately 1-1/2" behind the leading edge of the wing with no fuel in the tank. The model should be level to slightly nose-down at this CG.
- Use generous control throws during setup, then reduce to what you need. Recommended: 3/8" to 1/2" of up, down, left, and right is fine.
- Set the nose-wheel height so that the leading edge of the wing is 1/4" higher than the trailing edge (measured at the hingeline) with the model at rest on a flat surface.
- The trailing edge of the elevons should be set 1/2° up with the transmitter trim at neutral.
- Check all surfaces for proper motion: a left aileron command should result in the left elevon going up and the right elevon going down; an up elevator command should result in both elevons going up.
Flying: Flight performance is very smooth and graceful; it gives the feeling that the airplane is an extension of yourself in the air. It often seems to do the right thing before you command it. Bill Winter once said, "Why does my Simitar do what I want it to before I tell it to? Does it read my mind?"
Remember: be safe, be courteous to other fliers, and have fun and tight turns!
Why the Simitar?
The following is a compilation of the flight characteristics of the Simitar Series aircraft that result in performance advantages over aircraft with a conventional horizontal stabilizer and elevator:
- A Simitar will not tipstall. As you reduce power and pull up elevator, when it reaches the point where a conventional model would try to tipstall, it merely drops its nose and continues to fly straight ahead with the nose down a bit. The tail will never drop, cause a tip stall, and a crash.
- A Simitar will not tipstall during attempts to force a stab model into the air or to stretch the glide. That failure mode will not happen with a Simitar.
- A Simitar has a wider speed range. Given the same weight, power, and wing area as a conventional model, the Simitar will fly more slowly and, because it has less drag, will also fly faster.
- A Simitar is aerodynamically stable. Hands-off at 1/4 throttle, tap a bit of left aileron to raise the right wing tip slightly, let go, and a Simitar will do left-turn 360s until you say, "Quit!" Anyone who can tap left or right stick can fly a Simitar until the tank runs out and never have to touch up or down elevator. Since it will not stall, pitch control is not required for slow flying. (For first-time fliers, takeoff and landing should be done by the instructor.)
- Wind is not a problem with a Simitar. Adjust throttle to maintain zero ground speed and you can hover; ease off and it will fly backward. Vertical takeoffs and landings are feasible.
- A Simitar will perform all maneuvers a conventional Pattern model can do—often better and easier. It will tumble fore-and-aft as well as tip-to-tip. Flat spins and tight turns are no problem.
News commentator Paul Harvey recently made the statement, "Before too much longer, no aircraft will be built with horizontal tails."
SLOW-MOTION TRADITION
- Type: RC Sport
- Wingspan: 64 inches
- Engine: .40 two-stroke
- Functions: Elevon, rudder, throttle
- Flying weight: 4-1/2 pounds
- Construction: Built-up
- Covering/finish: Film
Bill Evans 454 Wildrose Ln. Bishop, CA 93514
Transcribed from original scans by AI. Minor OCR errors may remain.
