Facts about Van’s new high wing aircraft, the RV-15, were scarce until Oshkosh when the Engineering Prototype was revealed. We’ve been busy finding out all we can about the latest kitplane
Words: Dave Calderwood. Photos: Van's Aircraft and Ed Hicks
25 August 2022
The RV-15 is the newest kitplane from Van’s Aircraft, and it’s their first high-wing aircraft. The company has always been about delivering something they call ‘Total Performance’, and with the RV-15 they have applied their expertise to creating a backcountry-capable aircraft. That means an aircraft that’s intended to be short strip capable and is tolerant of rough surface operation, but can also able to cruise at a decent speed, lift a good-sized load, and carry at least two people.
Van’s brought along its Engineering Prototype to this year’s EAA AirVenture Oshkosh. The aircraft was only completed in late June when it was flown for the first time, and Van’s is still in the early stages of flight testing. This Engineering Prototype is a test aeroplane that Van’s is using to validate the design to help determine the final kit aircraft configuration. It’s important to remember that the aircraft customers will eventually build will differ in some respects. For instance, the huge flaps may change in size, the fuselage may be longer, a baggage door will be added, and things like the use of a temporary aerodynamic gurney flap ‘fix’ on the stabilator trailing edge will be addressed in refinement of the design.
In an interview with FLYER‘s Ed Hicks, Van’s president and Chief Technical Officer, Rian Johnson, said they had spotted a gap in the market. “There’s a lot of aeroplanes that started out as powered by smaller, less horsepower engines,” said Rian. “And they tried to expand those aeroplanes by putting larger power plants on them. But the airframe is still the airframe. There’s only so much baggage capacity.
“So we wanted to go out and have a real STOL (Short Takeoff and Landing) aeroplane, but not too far off the STOL end of the spectrum – we’re not out to win the Valdez STOL competition. ‘Total Performance’ is that happy medium.”
Key to the 15’s appeal is that it had to have crisp handling, typical of the RV low-wing range of aircraft, continued Rian.
“I want effective ailerons that are an extension of your thought process, just like the other RVs. In this aeroplane, we’ve achieved that. These are the largest chord ailerons that we’ve ever designed and we’ve still managed to have that crisp feel and eliminate adverse yaw.”
The Fowler flaps on the testbed RV-15 are huge and extend to 50° using an overhead handle mounted in the cabin ceiling. Rian admits they are an experiment because ‘we wanted to test some extremes’.
The large flaps work with an all-flying stabilator at the rear, chosen to avoid running out of elevator authority when landing on a really short strip such as a sandbar in a river. “Slow speed handling is key here,” said Rian.
The RV-15 has a wing that’s a new design for Van’s and not borrowed from its previous designs (something that Van’s has done in the past). It’s big at 34ft wingspan with wingtips that add another foot. Rian wants to trim that back to 34ft overall so the aircraft fits easily in a standard hangar.
The wing shape (‘airfoil’) is designed to avoid aggressive wing drop at slow speeds, say when making a spot landing. Rian credits the success of the wing design to Van’s Engineering Director, Rob Heap. “Rob’s contribution to the wing, and getting all the elements right, like the ailerons and flap tracks is impressive. The fact the aircraft stalls straight ahead out of the box and flies as well as it does, shows what good work he did.”
High-lift with docile stall characteristics, with the aim to operate at low, rather than high deck angles (typically seen with wings that use high-lift devices), is the Holy Grail for backcountry aircraft.
Construction is conventional. It’s all-aluminium with wing spars carrying through the cabin ceiling and faired struts each side.
Perhaps the cleverest piece of design on the RV-15 is the suspension for the main gear, which is packaged between the cabin’s flat floor and the bottom fuselage skin. “I suggested to the team that we needed suspension inside the fuselage. Engineer Brian Hickman went away and designed an ingenious solution that made that possible.”
There are four gas struts, two for each leg that provide five inches of stroke (travel) at the top, which translates to seven inches of travel at the bottom of the gear leg. Perfect for absorbing bumps when operating from rough strips.
“When we think about that outside the aeroplane, we no longer need 31 inch tyres,” said Rian. “If you have five inches of stroke, you’re not paying the weight penalty for those tyres.”
What’s more the gas struts can be ‘tuned’ to match the likely terrain. As standard they are filled with nitrogen, but if you’re out in the wild, you can use a hand pump to add air for a firmer setup – or let gas out if you want softer.
The innovation continues with the tailwheel, another piece designed by Hickman, which Van’s believes is the only tailwheel with a constant caster angle through its whole throw, avoiding the tendency to shimmy as the tailwheel spring is compressed. The tailwheel also has a gas strut to control its movement. Both the tailwheel and main gear designs have been patented by Van’s.
The cabin is huge and has equally large doors. Partly that’s because Van’s wants the RV-15 to be a load-lugger with plenty of space – a full-size mountain bicycle fits in – but it also recognises that some of the pilot population and its older customers aren’t as nimble as they used to be, and Van’s wants to make it easy for people to get in and out of the aircraft.
That starts with the seats being able to slide back to the B pillar and a specially shaped control stick to make it easy to slide your legs around it. The testbed’s seats aren’t the finished item either – they’re from an old Cessna, just because Van’s needed some seats quickly. The production versions will have a cut-out in the front of the seat so that when the aircraft’s parked, just slide the seat forwards and it will provide a control lock.
Rian also hinted at a nosewheel version for flight schools, with a third seat in the back for an observer – a popular configuration for flight schools. A 2+2 setup could also be an option for those who wish to trade some baggage capacity and weight.
Oh, and those huge doors add to the feeling of space and visibility with transparent panels running the full depth. A high-wing aircraft means being able to see the ground, so the doors were designed to maximise that experience. An alternative door is in the works that will offer the option to open the top half in flight.
The RV-15 is designed around Lycoming’s high performance IO-390 EXP119 engine rated at 215hp (also an option for the RV-14), with an option for a more conventional 180hp Lycoming. A Hartzell 80-inch Trailblazer propeller is currently fitted.
In cruise, the RV-15 should be happy at 140-145kt, though that’s still to be proved, and Van’s says it will not talk about a stall speed until it has fully tested the aircraft. The testbed aircraft has ‘lots of drag everywhere’ that Van’s will work on for production aircraft. But safe to say it will have a useful cruise speed much higher than backcountry rivals such as a Cub-based aircraft.
Probably after Oshkosh 2023. Price? We don’t know yet.
What we can say though is, based on the absolute swarm of people who continuously surrounded the aircraft throughout the seven days of AirVenture, and wore the grass that surrounded it to just dirt, the world’s most successful kitplane company has just added another popular product to its range.
Want to see how they designed and built the prototype? Check out the video below…
