Van Horn Composite Rotor Blades Lift Legacy Bells And MDs
Van Horn Aviation (VHA) of Tempe, Ariz., wants to put more life into legacy helicopters by developing products that increase performance and lower direct operating costs by focusing on composite main and tail-rotor blades. At Heli-Expo’13, VHA is showing five examples of its work, all with different stories: tail-rotor blades for the Bell 206, UH-1 and 212/214; and main rotor blades for the MD Helicopters MD530F and Bell 206B.
VHA (Booth No. N3924) has built more than 1,000 composite tail-rotor blades for the Bell 206 to date, making the product its most successful. “For a little company, we’re excited about that,” said Dean Rosenlof, general manager. “We have only 15 employees, but we’re putting out 50 Bell 206 blades a month.” The company was founded and is owned by its president, James Van Horn, a former U.S. Army helicopter pilot who was chief engineer for McDonnell Douglas for the MD500. A mechanical engineer, Van Horn does most of the design work at VHA, Rosenlof said.
Another significance of VHA’s 206 tail-rotor blade is the fact that, last December, VHA entered into an exclusive agreement with Bell Helicopter to distribute VHA’s composite blades for the 206B3, 206L series and OH-58A+/C. So now VHA sells these blades through Bell’s distribution network, instead of from VHA’s factory and distributors. VHA also builds and sells composite tail-rotor blades for various models of the UH-1 Huey.
The company is currently developing two new composite main-rotor blades for the MD530F and the Bell 206B, examples of which are on display here. The MD530F blade is getting close to production.
“Our composite blades are similar in composition, but not exactly the same,” Rosenlof told AIN. “For one thing, the airfoil was modified. We did a fairly large leap in technology with the 206 tail-rotor blade and we’re doing developmental changes on the MD530F main-rotor blade. But, still, they are both carbon-fiber blades with a foam core.”
VHA flew the first iteration of its MD530F main-rotor blade two years ago. “We went from track-and-balance, to hover, to forward flight in two hours, and we had pretty high control loads.” Rosenlof explained. “We hovered it and saw we needed to make changes to the design. We then created a new set of blades and did extensive flight testing this summer. We learned some things and decided to do another revision. We changed a lot of internal components and pieces.” More carbon-fiber plies were added to increase the torsional stiffness of the blades and the layup process was modified to make it more efficient. Then VHA’s contract test pilot, Greg Ashe, flew the blades again.
The blade design was good, but not good enough. “So we said, ‘Let’s just fix this,’” Rosenlof said. “We know it’s not a strength issue, but stiffness. We made new tooling and components and put the blade together. The blade we’re showing at Heli-Expo is literally our first article. After the show we’ll build more blades and fly again in April. We know what we’re looking for and hope to complete our flight test quickly–where we wanted to be seven months ago.
“Everything we’ve learned on the 530 blade we’re adopting into the 206B main rotor blade,” he said. The 206B blade is a significantly bigger blade than the 530 and has a different root design. It is a more rigid system with a much different hub attachment. We get to design only from the blade attachment out, so it forces us to make changes to the blade, not the hub. It’s incremental growth: learn, fly, learn, make a change. The testing teaches us what we don’t know.”
VHA is currently working on a Bell 212/412 tail-rotor blade. “The blade has enough ADs on it that we decided it would be a good idea for us to do a composite blade,” Rosenlof said. A prototype of that blade is also at the show.
Future projects include a composite tail-rotor blade for the MD500 and a drive-train modification for the MD530F. “The idea is to increase the length of the tail boom of the 500E so it can fly with the slightly longer blades of the 530F,” he said. The diameter of MD500E’s rotor disc is 26.4 feet, while the MD530F’s is 27.35 feet. “We’ll give customers a kit to turn a 500E into a 530F with the E’s engine. This will provide the hover performance and flying characteristics of the F at low altitude. All you would lose is the higher altitude capability of the F’s bigger engine.” The MD530F is powered by a 650-shp Rolls-Royce 250-C30 turboshaft engine, while the MD500E is powered by either a 420-shp 250-C20B or a 450-shp 250-C20R.
To date, VHA has been leasing and borrowing helicopters for its flight testing. But with the additional work needed to do the tailboom modification, plans are to buy a used MD500E “because we’ll be cutting into it,” said Rosenlof. “Owners aren’t too happy if you do that when they lend you their helicopter.”
He estimates that the company has, under its current business plan, perhaps five to 10 years of work ahead. The MD500F tailboom mod and Bell 212/412 tail rotor will take time, and then there are tail- and main rotor iterations of the current projects to consider, including the MD500D, E and C rotor blades; and the 206L series LongRanger main-rotor blades. Rosenlof said it currently takes the company about two to three years to develop a new blade, but acquiring its own helicopter for test work could shorten the development time. With all this work for MD and Bell helicopters on its horizon, VHA is not currently considering providing composite rotor blades for legacy Eurocopter, Robinson or other manufacturers’ models.
Founded in 2001, VHA delivered its first rotor blades to customers in 2005.