Archive for March, 2011

Wheels or skids?

Wednesday, March 30th, 2011

When it comes to landing gear, helicopters have two basic types: skids and wheels. Skid gear is always fixed and wheels can be fixed or retractable. Which one is better depends on the mission the helicopter is performing.

Skid landing gear is simple and lighter weight, so it is the best choice for small helicopters as weight is always a consideration. Also, skid landing gear needs very little maintenance, but the drawback is that ground handling is more difficult. In very small helicopters (such as the Robinson) ground handling wheels can be attached to the skids and the helicopter moved around by one person. Larger helicopters (such as the Bell 206 or AS350) can be moved around with ground-handling wheels, but it normally takes a couple of people. There are a variety of power-assisted tugs and transporters that can help someone move larger helicopters by themselves. Another method of ground handling that operators use is a platform dolly that the pilot can land on and then tug the dolly and helicopter around. However, pilots need to be comfortable with dolly landings as several accidents have happened from pilots misjudging the landing.

On larger more powerful twin-engine helicopters weight is not as big of a concern and retractable wheels make sense. Wheels are nice because a helicopter can ground taxi (as opposed to hover taxi) around other aircraft and people without worrying about producing a high downwash. Retracting the gear also reduces drag, allowing for a higher cruise speed. Attaching a tow bar to the nose wheel makes moving the helicopter around a lot easier as well.

The engineering decision to use retractable wheels or fixed skids is basically a trade off. The retractable wheels give better speed, ease of handling, and the ability to ground taxi. However, they are more complex, require more maintenance, and increase the weight.

Bell 206 with skid gear

Bell 430 with retractable wheels

Canyon noise

Tuesday, March 22nd, 2011

Noise is an issue that helicopter operators deal with on a daily basis – some more than others. For the tour companies who fly over the Grand Canyon it is a battle. Just recently, the National Park Service (NPS) proposed new rules that would limit the total number of flights over the canyon and require the use of “quiet technology” helicopters within 10 years. 

Tour operators understand and support the initiative to reduce noise in the park. Many are upgrading their fleets to quieter models like the Eurocopter EC130B4 (also known as the EcoStar); however, they oppose capping the number of flights. Currently, there are just over 400 flights on average per day and the new proposed rule would limit that to 364. Many operators are reporting double-digit growth, so there’s clearly demand to see the canyon by air. 

It’s hard for humans to experience the beauty of remote areas of the earth without leaving some evidence of our visit. For example, if some of the hard to reach areas of the canyon were to be explored by tour bus, roads would have to be built destroying the natural state of the landscape. At least helicopter noise leaves no lasting mark. I agree that the natural quiet of these areas should be protected. The emphasis should be on noise reduction not reducing the number of flights and consequently the number of people who can enjoy these areas. 

In the coming months the NPS will hold several public meetings in Arizona, Utah and Nevada to hear public input. The comment period ends on June 6, 2011.

China rising

Friday, March 11th, 2011

I just returned from HELIEXPO 2011. Held in Orlando, FL this year, it is the Helicopter Association International’s largest show and exposition. Many attendees look for announcements and industry outlooks from the manufactures. This year the mood was very upbeat for the future health of the helicopter industry. Part of this optimism comes from China. 

A recent change in the country’s low-level airspace rules has paved the way for civilian helicopter operations. Currently there are 200 civil helicopters in China and according to Chinese officials that number is expected to increase to 3,000 by 2020. Not wasting any time, a consortium of Chinese aviation companies signed a memorandum of understanding with Erickson Air-Crane that includes the purchase of up to 5 S-64F Air-Cranes. 

Chinese officials also announced, China Helicopter Exposition 2011 – the first edition of a unique show dedicated to the rotorcraft industry and scheduled to run from September 15th to the 18th. It is a direct initiative from Aviation Industry Corporation of China (AVIC) and heavily supported by the central government. AVIC helicopter division, AVICOPTER, has invested over $800 billion in a research center and a helicopter production facility in Tianjin. When completed the factory will be manufacturing 30 thirty-ton aircraft, 40 ten-ton aircraft and 170 light aircraft a year. This investment shows how serious the country’s desire is to develop a national rotor aircraft industry. The Tianjin factory is expected to grow its production by 17% annually. This provides opportunities for foreign companies to support what is going to become a major growth area in the global helicopter industry.