The original concept and final design Stinger appear to share only two things. First is the name – S-17 Stinger – and the second is the little bumblebee logo. In every other case I could discern, the finished Stinger is a totally new design from Randy Schlitter’s original idea. Stinger version two flew for the first time on September 10, 1999. Barely a week later, I found myself aloft in the new ultralight. Normally, I’m not anxious to jump into a manufacturer’s brand-new design. I much prefer waiting until they have the design fully worked out. However, Randy Schlitter has an excellent reputation for airplanes that seem to fly right off the drawing board (or out of the CAD program these days). He’d put some hours on the Stinger and had given it his blessing. I observed him fly it first and by all measures, it appeared to be ready for evaluation flying.
|Empty weight||290 pounds|
|Gross weight||527 pounds|
|Wing area||127 square feet|
|Wing loading||4.1 pounds per square foot|
|Build time||100 hours|
|Standard engine||Rotax 447|
|Power||40 hp at 6,500 rpm|
|Power loading||13.2 pounds per horsepower|
|Cruise speed||(75% power) 55 mph|
|Never exceed speed||(Vne) 95 mph|
|Rate of climb at gross||900 fpm|
|Takeoff distance at gross||100 feet|
|Landing distance at gross||100 feet|
|Standard Features||Removable strut-braced wings, center-mounted joystick, outboard ailerons, 4-point restraint systems, 2-blade IvoProp propeller.|
|Options||Drum brakes, 3-blade prop, instruments (airspeed indicator, altimeter, tachometer, temp, hour meter), aluminum wheels.|
|Construction||Aluminum tubing, welded steel, Dacron® sailcloth.|
Cosmetic appearance, structural integrity, achievement of design goals, effectiveness of aerodynamics, ergonomics.
Pros - Second version of all-new RANS Stinger is also the company's newest aircraft. Done in the tradition of other company aircraft using components from other models. Good all-around capabilities rendered as an ultralight aircraft should be. Stout design, felt good in air and on landing approaches. Should satisfy many buyers.
Cons - A few minor points need to be worked out yet (although the design will surely see the usual Schlitter refinements). Cannot fit under FAR Part 103 without some significant changes compared to test aircraft. Enclosure and side walls to comfort some buyers would render the aircraft less ultralight-like.
Subsystems available to pilot such as: Flaps; Fuel sources; Electric start; In-air restart; Brakes; Engine controls; Navigations; Radio; (items covered may be optional).
Pros - Test Stinger had brakes (even a parking brake). Engine access is good (though a small step would be helpful). Nice space for instrument deck; if small gauges used, could hold many. Stinger's simplicity is among its virtues; hopefully buyers won't load it up. Throttle is now standardized; first prototype utilized a nonstandard twist grip.
Cons - No flaps, in-flight starting (pull or electric), remote choke, or trim. A radio would require a wired helmet headset and a pocket or bracket somewhere to hold the radio. Fuel filler on wing top is not particularly convenient. Brakes are unidirectional only.
Instrumentation; Ergonomics of controls; Creature comforts; (items covered may be optional).
Pros - Reminiscent of Air-Bike (step-over seating) or UltraStar (not much in front of you). Delightful open cockpit experience for those who like such aircraft. Entry doesn't get much easier. Small but comfortable seat. Superbly secure seat restraint (though this will change from that tested).
Cons - Rudder heel brace is needed as nothing else keeps your feet off the ground; supports were small around my shoes. No cargo area. Some pilots will dislike the lack of any side walls.
Taxi visibility; Steering; Turn radius; Shock absorption; Stance/Stability; Braking.
Pros - Steering is very good on hard or soft surface (though a smaller tailwheel is needed on Part 103 version). Visibility doesn't get much wider than this; you can see everything. Brakes are effective enough that you can use the park-brake tab while pull starting from outside the Stinger. Adequate clearance for most off-field landings.
Cons - Tight taxi turns are difficult (same for most taildraggers without differential braking). First Stinger prototype reportedly quite a handful on the ground (problem solved with the final Stinger). No suspension other than tube flex and air in the tires; light enough to not require much, however.
Qualities; Efficiency; Ease; Comparative values.
Pros - Takeoff and landing are level-attitude tasks; you don't rotate nose skyward on liftoff, "levitating" instead. Very straightforward launch characteristics. Good control authority for crosswind operations. Visibility on takeoff or landing approach is huge. With slow flying speeds, most short runways will be easy to use.
Cons - Needs more nose height (steeper deck angle) to allow three-point landings; tends to touch tailwheel first as is, however, Stinger's posture also reduces need for taildragger skills. Slips won't be too effective due to little vertical area and no flaps, though neither is hardly needed for short landings.
Quality and quantity for: Coordination; Authority; Pressures; Response; and Coupling.
Pros - Remarkably little adverse yaw, thanks partly to differential movement and outboard ailerons (as opposed to full-span designs). Dutch rolls went well to good angles very quickly. Control harmony appeared to be very good. Control power is good enough to fly in winds to 25 mph or so, and enough for most crosswind conditions.
Cons - Joystick range is adequate although you may want to trade lightness for greater control surface deflection when building your own Stinger. Rudder pedal position was not optimal for me (pedals angled too far back).
Climb; Glide; Sink; Cruise/stall/max speeds; Endurance; Range; Maneuverability.
Pros - Strong climb with 40-hp Rotax 447 at 900 fpm, says RANS. Takeoff and landing distances are less than 100 feet. Max cruise is 55 mph. Did very well in low-over-the-field flying. Slow flight characteristics - enjoyed by many enthusiasts - are excellent.
Cons - Max speed isn't swift enough for some (though they should then be looking at other aircraft). Rotax 447 won't be used on Part 103 model; 2si will be required but has not yet been fitted. Took better than 5,000 rpm to hold altitude, suggesting fuel economy may be low.
Stall recovery and characteristics; Dampening; Spiral stability; Adverse yaw qualities.
Pros - Stalls were mild with only a modest wandering of nose. Power-on stall never broke. Longitudinal stability appeared to be fine, although you have no control to fix any trim problems. Extremely robust seat restraints installed in test Stinger. Adverse yaw is very minimal; hesitates without moving, then turns correctly.
Cons - All stalls wandered a bit at the top of a stall; tended to fall gently to right (though this may have been due to my power setting and P-factor). Power-up tends to lower nose as on many top-of-wing pusher ultralights.
Addresses the questions: "Will a buyer get what he/she expects to buy, and did the designer/builder achieve the chosen goal?"
Pros - Newest RANS model is now in production; company's strong reputation should assure many sales. Customer support, manuals, refinements, and accessories will surely be as good as for the rest of the company's models. At under $11,000 complete, price is competitive with many ultralight singles. Build time expected in 100-hour range. RANS dealers are located all over the world.
Cons - Stinger is so new, it has not yet established a market. Part 103 model popularity yet to be determined given diminished equipment list (compared to test model). Not for those who require full enclosures to feel protected.