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Society posts prizes to save Bonanza fleet

Rewards offered for corrosion solutions

Beechcraft engineers used magnesium to skin the ruddervators of V-tail Bonanzas dating back to 1947, and magnesium has since become very hard to come by. Engineering an alternative that works as well could earn an engineer, or team of engineers, a share of $200,000 as a reward for saving the fleet from being forever grounded by corrosion.

The ruddervator control surfaces on the tails of Model 35 Bonanzas are skinned in expensive and hard-to-find magnesium that is notoriously vulnerable to corrosion. APOA file photo.

The American Bonanza Society Air Safety Foundation put the word out April 30 that two separate prizes are available: up to $20,000 each awarded to as many as five individuals or teams who engineer a ruddervator skinned with something other than magnesium. Solutions must be shared as open source technology and survive peer review. Successful engineering solutions can then be used by the creator, or someone else, to claim a $100,000 prize offered for being the first to secure a supplemental type certificate for a reskinned or replaced ruddervator available to all Beech Model 35 Bonanzas covered by existing type certificates A-777 and 3A15.

It might sound simple, but it’s not, or it would have been done long since. ABS Air Safety Foundation Executive Director Tom Turner told AOPA that the dwindling supply of magnesium has been well known and worsening for a long time, and the hope is to find a different material to cover the flight control surfaces on each side of the V35 Bonanzas. A straight tail can be reskinned in aluminum, but some unique characteristics of the ruddervators installed on all V35 models preclude that.

For one, being as far aft of the center of gravity as it gets, the ruddervator control surfaces must be as lightweight as possible. Magnesium also confers unique properties that protect against control surface flutter, Turner added. So far, nobody has figured out a substitute that can do all that magnesium can do without corroding as magnesium does—very quickly, if any part of the metal is exposed. Paint chips are anathema to V-tail Bonanza owners, and corrosion threatens the long-term airworthiness of the entire fleet.

Turner said Textron Aviation, which owns Beechcraft and all of its type certificates, is attempting to source the high-grade magnesium in large enough quantity to meet the need, and may also be attempting to reengineer the ruddervators.

“It’s difficult to get different types of materials to achieve the same control flutter protection,” Turner said.

The Wichita, Kansas-based organization is funding the prizes with a bequest from Manuel Maciel, and “we think this is one of the best possible uses of this money,” Turner said.

While the deadline for a completed STC to be eligible for the $100,000 prize is Dec. 31, 2025, Turner and the owners of V-tail Bonanzas hope an answer might come sooner. Turner said that they set the deadline farther out than anyone really wants to wait because the work will take time, and the society did not want to “limit potential contenders.”

The deadline for submitting a materials-tested solution that is eligible for FAA evaluation and an STC application is June 1, 2023. Universities and private firms with metallurgical expertise and access to materials testing equipment are in the best position to come through, along with aircraft manufacturers. While the rules don’t preclude the use of magnesium entirely, the $100,000 prize winner will have to have produced five retrofit kits or finished control surface units at a price no more than 20 percent greater than what is currently available.

Detailed rules and technical specifications are included in this document. And go!

Jim Moore

Jim Moore

Managing Editor-Digital Media
Digital Media Managing Editor Jim Moore joined AOPA in 2011 and is an instrument-rated private pilot, as well as a certificated remote pilot, who enjoys competition aerobatics and flying drones.
Topics: Aircraft Modifications, Financial, Ownership

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