Light Sport, Done the Van’s Way

This proof-of-concept RV-12 will evolve into an amateur-built LSA.

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If you know much about Dick VanGrunsven and his company—Van’s Aircraft in Aurora, Oregon—you know that they might both be described as conservative in the best sense of the word. Van’s personal and professional reputation comes from his commitment to design and test fast, safe and efficient sport aircraft, turn out reasonably priced kits, and support his customers over the long haul. The result is the RV series. More than 5000 RVs built from kits are finished and flying.

Van’s personal penchant for fast, efficient transportation plus the limited aerobatic capability of some of the RVs may have caused a few raised eyebrows when he participated in early meetings about the proposed Light Sport Aircraft (LSA) category. That’s because LSA and the accompanying Sport Pilot license grew out of the ultralight community and were seen as near the bottom rung on the aviation ladder. But we should not have been surprised, as Van’s interests include many types of sport flying. For example, he’s been an active glider pilot for years and often flies his Schempp-Hirth 18-meter Ventus II CM sailplane.

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A Twinkle in Van’s Eye

Early in the LSA volunteer consensus standards process, which got underway in 2000, rumors began to circulate that Van might design an airplane to meet the standards once they became firm. That process took several years to shake out. Other commitments at Van’s such as gearing up to meet the demand for RV-10 kits slowed the company’s LSA project. But in 2005, Van’s acknowledged that work was underway on the company’s LSA, which was to be known as the RV-12. (The RV-11 is a motorglider project that sits on a back burner somewhere.)

Not yet completed, the RV-12 was displayed and drew crowds at AirVenture/Oshkosh ’06. The first flight of the proof-of-concept plane was in November ’06. Fall and winter weather slowed flight testing, and the first public outing was to nearby EAA Chapter 292 in Independence, Oregon, in February of 2007. Chapter members were enthusiastic enough that many of them would like to build an RV-12 as the next group project.

RV of a Different Stripe

The EAA chapter visit revealed significant departures from previous RVs. The POC RV-12 scored a list of firsts among VanGrunsven designs. They include a 100-horsepower Rotax 912S for power, a stabilator and anti-servo tab for pitch control, primarily pulled rivets instead of solid rivet fasteners, plug-in wings for quick ground transportation (glider style), flaperons instead of separate ailerons and flaps, and flat-panel, solid-state instrumentation (EFIS) displays, possibly as standard equipment.

VanGrunsven is chairman of the design committee and decided the mission of the airplane. It is closely defined by the LSA rules, but Van had the vision for some of the major variations to the well-known RV theme.

Rotax power is an example of working outside the box for Van’s, but it’s close to standard fare for most new LSAs, because the engine is light, powerful and durable. A better example is the plug-in wings with automatic aileron (flaperon) hookup. Van is an avid competition glider pilot, and high-performance gliders have for more than 40 years featured easily attached wings with automatic control hookup. An extension of the plug-in wings concept on the RV-12 is an aluminum plate with a handgrip on each wingtip.

One design decision leads directly to others. Practical plug-in wings eliminate the wing fuel tanks found in other recent RVs. Therefore, the RV-12’s 20-gallon aluminum tank sits behind the right seat and behind the mainspar.

Another result of plug-in wings was moving the pitot tube to a non-conventional place. It’s a non-rotating aluminum tube that protrudes through the prop spinner about an inch—a feature allowed by the Rotax 912 engine’s hollow propshaft. The WW-II Bf/Me 109 fighter had a similar feature, but it was for letting bullets out rather than air pressure in. (I know what you’re thinking. Don’t do it. There are better ways to enforce pattern discipline.)

On the proof-of-concept RV-12 I flew, there is also a conventional wing-mounted pitot tube. It feeds one of two different EFIS devices on the test airplane’s panel. During flight tests at very high angles of attack, the spinner pitot tube reported airspeed much too low. The solution was to bevel the end of the spinner pitot so that pressure would be sampled even at high AOAs. Now the two electronic airspeed indicators read the same at well below stall speed.

One system unique to the RV-12 is use of a stabilator and anti-servo tab for pitch control and electric pitch trim. The added pitch authority of a stabilator compared with a horizontal stabilizer and elevator allows a smaller horizontal tail. This makes it possible to leave the tail on for trailering; the stabilator span is 8 feet, short enough to meet maximum-width road towing rules.

Another departure from Van’s usual practice is the use of pulled rivets through most of the airframe. Some solid rivets are required, but these can be installed with a rivet squeezer rather than a rivet gun. (What fun is that? You can’t keep the family awake with a rivet squeezer.)

Yet another goal was to minimize fiberglass fairings, which are heavy and labor-intensive (expensive in a factory or messy and time-consuming at home). You’ll find a fiberglass cowl on the –12 but few other glass parts, with the possible exception of glass-cockpit instrumentation. Van’s may depart from letting its customers choose all avionics by supplying an EFIS with the kit. That

decision plus design around the Rotax 912 ULS engine would greatly simplify completion of the kit, as it would standardize most of the panel hookups and systems.

The Modern Way

With baseline decisions made either by VanGrunsven or LSA requirements, the criteria were fed into computers by lead engineer Ken Krueger and other members of the engineering team. The design committee could then come up with options to meet all requirements. Engineers Phil Rivall, Rian Johnson and Michael Schwartz are the other current team members, each working on a specific design area. Krueger and Johnson built their own RVs, and their input includes concerns for ease of kit construction and owner maintenance. Advice from the two prototype shop mechanics was also used in the design. One of the goals is to not require pneumatic tools to build the -12. The committee process is informal and continuous.

Studying the preliminary pilot operating handbook, I noted an electric fuel pump near the tank but no switch on the panel for it. Krueger explained that for pilot workload reduction and considering the pump’s long design life, the pump remains energized when the master switch is on. A fuel-pressure gauge shows whether the pump is working, and a pressure minimum is on the pre-takeoff checklist. There is an easily pulled, clearly labeled automotive fuse on the panel, and the engine gets enough fuel for normal operation even with the electric pump off. Tankage is 20 gallons of 92 octane auto fuel (preferred) or 100 LL with TCP.

Another change from other RV designs is that people sit forward of the wingspar rather than on it. This “cab-forward” feature, made possible by the lightweight Rotax engine, provides good visibility in all directions, especially downward in front of the wing’s leading edge.

Design cg locations for this airplane range from 15-29% of mean aerodynamic chord (MAC), but the kit version RV-12 numbers may be a bit different. The POC airplane is slightly tail-heavy. That will be corrected in the kit version, which is currently under construction.

A major change in the kit RV-12 will be increased wing chord, which will increase wing area. Another change will be a castering nosewheel and toe-operated wheel brakes (left side standard, additional right toe brakes optional) instead of the prototype’s direct nosewheel steering and non-differential bicycle-grip braking on the sticks.

OK, Go…

The RV-12’s seatbacks are ground adjustable fore and aft, but I used a thin cushion to get my legs closer to the pedals. That allowed easy full pedal deflection, but I would have benefited from moving the seat forward so that the center-mounted throttle would require less of a stretch with the throttle arm.

Non-differential bicycle-grip wheel braking and direct nosewheel steering made the RV-12 easy to navigate on the ground, but this feature will go away with the kit version. Preflight, engine start (instantaneous like a car), taxi and pre-takeoff checks were Rotax normal. There is no mixture control.

Electric pitch trim and half flaps were set. We checked the pattern, made our takeoff call, and quickly accelerated to the recommended 45-knot rotation speed. Holding best-angle climb (half flaps, 65 knots) for a few hundred feet of altitude, then slowly raising the mechanical flaps resulted in the best-rate 75-knot climb without needing a trim change. I held fairly closely to 75 knots and saw a climb of about 800 fpm. Above pattern altitude, we angled off to an open area southwest of Aurora and continued to 2000 feet.

First I tried my standard 45° to 45° roll

rate check. True to Van’s philosophy of light, effective ailerons, the RV-12 completed this full-aileron, some-rudder-deflection task in less than 2 seconds in both directions from a leisurely 90-knot cruise. That’s a snappy roll for this category airplane at that airspeed.

Next came the pitch stability check, which had the nose back at trimmed airspeed and attitude about four slow cycles from the start of my slight pitch-up-and-let-go initiation. Krueger noted that thorough flight-testing confirmed pitch stability throughout the cg and weight envelope. Worst case is full fuel and baggage and a light solo pilot. In some cases it could be necessary to strap luggage into the empty seat and reduce fuel to be within the envelope. Calculations show that on our flight, cg was at 26.2% MAC.

Approach stalls were sampled in all three flap configurations: up, half and full. The LSA requirement for maximum power-off stall speed in clean (flaps up) configuration is 45 knots CAS at maximum gross weight (1320 pounds). We had nearly full fuel and no baggage, but Krueger and I totaled only about 312 pounds, resulting in a flying weight of 1154 pounds—166 pounds under maximum gross weight. At 1320 pounds, the 45-knot stall would be exceeded slightly, which is why kit RV-12s will have a slightly larger-chord wing. Half- and full-flap deflection slowed the stall break a few knots, and there was no wing drop or significant pitch down in any of the three stalls. Krueger noted that little trim change is needed with flaps. When necessary, you can fly the airplane with stick pressure and take pressure off your hand with the panel-mounted trim rocker switch when you get around to it. This is in contrast to some other similar-class airplanes that require significant trim changes with every new airspeed.

Setting 4800 rpm (700 rpm less than maximum continuous allowable power) for a partial-power departure stall, I needed a really high deck angle and lots of pull to get the break, which was near 43 knots IAS. The right wing dropped despite the slip/slid ball being centered with considerable right leg power, but recovery was quick and resulted in little altitude loss. I tried slow flight at 55 knots IAS, with and without trimming; both versions were comfortable. Maximum continuous power resulted in a calibrated airspeed of 114 knots level at 2500 feet.

Entering the uncontrolled traffic pattern on a long 45° leg to the downwind, I zipped along at 80 knots (maximum flap speed). There’s no carb heat control and no mixture knob, so the landing checklist consists of airspeed, flaps and trim. I like a tight, close-in pattern, and I should have slowed and deployed flaps on the downwind, but I didn’t and ended up high and fast on final.

Fortunately, slips are OK with flaps, and I used nearly full slips on much of the short final, straightening for a 65-

knot final approach. That speed is higher than recommended, so we floated above the runway for a while before a nose-high touchdown. The RV-12 handled my first landing attempt well. We taxied back, and Krueger made a takeoff and a landing. I noted a 1000-fpm climb on his departure. He also used a slip on final, maybe to make me feel better about my approach.

As with all the other Van’s Aircraft airplanes I’ve sampled over the years, the RV-12 flies beautifully. The roll is crisp, stick loads even at top speed are light enough to be comfortable, and nothing is twitchy. Other RV builders/owners may covet the speed and mild aerobatic capability of their machines, but they would certainly recognize the RV-12’s main attributes as continuing the long line of VanGrunsven’s legendary quality and handling.

What’s Ahead?

It’s too early to predict the future of the LSA marketplace and the RV-12’s place in it, but VanGrunsven has long been dedicated to affordable, safe, high-quality sport aviation. This brief acquaintance with the proof-of-concept prototype suggests that the RV-12 will do nothing to diminish the Van’s Aircraft reputation.

So far, there’s no product release date, and kit prices are not being confirmed. As this was written, the kit version RV-12 had not flown, and the company prides itself on exceptionally thorough testing, documentation, and truth telling regarding its products. For those waiting for an RV-12 kit to show up at the front door, patience may be a virtue. VanGrunsven sees safety and affordability as the keys to getting younger pilots involved. With its punched, matched holes, pulled-rivet fasteners, and power and avionics systems likely to be standardized, the RV-12 should be a delight to build quickly, making up for the wait to get the product. I want one. 

For more information on the Van’s Aircraft RV-12, call 503/678-6545 or visit www.vansaircraft.com. A direct link can be found at www.kitplanes.com.

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Dave Martin
Dave Martin served as editor of this magazine for 17 years and began aviation journalism evaluating ultralights in the early ’80s. A former CFI (airplanes, gliders, instruments), he’s flown more than 160 aircraft types plus 60 ultralights (including a single-seat, no-basket hot air balloon). Now living at a residential airpark in Oregon, he flies his new Van’s Aircraft RV-12.

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