Mathisen says, "There has been a big change in the way we manufacture the floats — all the way from the materials that we use to the coatings we put on the floats. We are using different alloys and plating processes that significantly improve corrosion protection. Additionally, for floats that operate in salt water environments, a zinc sacrificial anode is installed on the floats."
In addition to pre-priming the metal prior to manufacturing, the company takes small steps like installing Teflon® tape under stainless nut plates during installation to inhibit electrolysis or dissimilar metal corrosion. Additionally, it paints all rivets after assembly and coats all exposed hardware with a corrosion prevention compound.
Mathisen says that the key to preventing corrosion in the field is to seal any metal against exposure to the elements. "If you can seal it from the environment, it will last forever."
Mathisen says maintenance of the landing gear system is quite simple as it utilizes commonly available parts where possible. The wheel and tire and brake assemblies are available through most parts distributors. The main gear is custom designed by us.
He continues, "All nose landing gear systems are essentially the same on our floats with the only change being the size of the components. In addition, there is a change in the materials used for the nose gear strut on older floats. Larger nose gears utilize a 3M™ scotch ply, (composite) strut. The smaller used steel for the struts. All current floats; however, regardless of size, use the 3M™ scotch ply, (composite) struts.
For the main gear, the small floats utilize a track system and a neoprene biscuit, similar to a Mooney main gear, while the large floats use an oleo strut with dual main gears."
Due to a combination of the unusual loads and stresses placed on the floats, as well as the fact that they need to be water tight, Wipaire worked with 3M to develop a system years ago to bond the seams of the floats with a special heat-cured 3M adhesive. Many technicians in the field are unfamiliar with this system and are reluctant to make repairs. Mathisen says, "In actuality, the system allows total field repairs to chines and keels without having to debond anything. The main theme in repairing the floats is that the gunwall, chines, and keels, on the floats have an existing gap allowing for field repairs. All that's really needed is to remove the filler/sealant between gunwall, chines, or keels and the original skin; remove the damaged skin, and then place your patch into position and rivet it into place using the maintenance manual or approved sheet metal procedures as outlined in 43.13. The beauty of this existing gap is you don't have to remove the skin from the existing chines and keels and damage the integrity of the float. All you have to do is remove the damaged skin and insert new sheet metal in the space provided and seal it with PRC1422 or equivalent sealant."
Additionally, repair parts to include custom sized replacement cap splices for the keel, are readily available by calling the factory or service centers.
For any further information or assistance, contact Wipaire at 8520 River Road, Inver Grove Heights, MN, 55076, or call Mark Mathisen; (612) 451-1205 Fax (612) 457-7858. Web address is www.wipaire.com
Flight testing also completed, and application filed for a gross weight increase.
Powered by the new Pratt & Whitney Canada PT6A-140 engine, the available power in the Grand Caravan EX has increased almost 25 percent, from 675 HP to 867 HP.
Agreement authorizes Wipaire as a StandardAero-approved installation facility for the Cessna Caravan 208-series aircraft engine-upgrade program.
The company expects to complete the float installation approval and begin taking orders in the Spring of 2010.