Seaplane Preparation / Part 4 of 5

HydraulicFloatPump

Taking 13 years to build this airplane came with a price.

Have you heard of an AM/FM CD player, a VOR antenna, and a hydraulic pump to raise and lower the landing gear?  By the time I was done building the airplane all of these items were obsolete and replaced with something newer and better!  The tape deck was replaced with a tiny MP3 Player.  The VOR was replaced with GPS and the hydraulic pump was replaced with an electric motor system.  For seaplane preparation I made an extensive installation of a hydraulic pump, oil line network and electric plug and play set-up.  The hydraulic system is used to raise and lower the two main gear wheels and the castering forward gear.  I made the pump demountable so it would only be carried when floats were attached. The wiring harness and all the gear warning lights were all pre-wired with easy plug-ins.  All I needed were the floats.  As with the other afore-mentioned items I  became aware that my extensive accommodation for hydraulically operated floats was no longer needed.  The float company now uses an electrically driven motor system.  They did offer to buy back the pump if I purchase the new floats but how about all the oil lines and electrics I installed previously.  Oh well, I’m just too slow a builder to keep up with technology!

PS; The Clamar floats pictured above are on Larry Bauers seaplane and use the same hydraulic system as described above.

Seaplane Preparation / Part 3 of 5

liftringphotos-1

Other considerations needed beyond welding mounts and rudder retract tubes included attachment of the interconnect pulleys that connect the air rudder to the two water rudders. I purchased a set of EDO float installation drawings from Kenmore Air along with the specified pulley hardware. There’s a pulley on each side of the lower rear longerons and another balance pulley mounted between them on a crossover tube that completes the cable circuit. The brackets remained attached during the fabric skin assembly but the pulleys were removed and stored until needed for the later float installation.

Seaplane doors are basically gull wing doors that open up and away from the prop wash.  Additionally, it allows the pilot and/or passenger to quickly depart the cockpit to grab a rope or a dock.  A conventional side hinged door would be deflected by the prop wash making it difficult to open and quickly depart the cabin.

During the building process I had talked with other builders and seaplane pilots about the necessity of using a ventral fin for the float installation.  The fixed ventral fin fits on the rear underside of the fuse and adds to the overall rudder surface area giving the airplane more directional stability.  The problem is that not every pilot agrees and not every seaplane needs it.  I decided to cover my bases just in case and found  a ventral fin for sale in Canada.

In the early building stage it was difficult to think ahead of the day how I would actually raise the aircraft, remove the wheel gear and install the floats.  Luckily, the wing kit I built  had a very simple solution on how this would be done. It basically consists of a pair of “U” shaped metal fittings that fit over the wing spar bracket using the same through bolt. The top of the “U” has a welded shoulder nut that permits a large 3/8″ threaded eyebolt to attach to.  You only attach the eyebolts when their needed for lifting thus no need to fly around with them. Also this is the perfect place to lift the airplane since it is common with the center of gravity location of the complete airframe.

Seaplane Preparation / Part 2 of 5

aft float fitting

The floats are attached using the same forward attach points as the main wheel gear but requires a special “Aft” fitting for the rear float attach points. The aft float fitting assembly is available from Atlee Dodge of Anchorage Alaska who specialize in Cub type parts.  The fitting is a heavy duty steel plate that is welded over the cluster of  longeron, crossover and vertical tube intersections.  It is designed to attach the rear float struts and float brace wires. While welding these fittings on I also welded on the front seat belt retractor mount plates.

Another item on my seaplane welding prep list was the provision for mounting a tube below the aircrafts belly that is used to pull a cable through that allows the water rudders to be retracted after a water take-off. The tube would only be attached when the floats are installed so I needed to weld a larger tube insert in the cockpit for the cable retract tube to attach to. The water rudders  are located on the stern of each float and are interconnected with the air rudders and rudder pedals. They assist steering the seaplane while on water and are manually retracted by the pilot with a cable attached chain that attaches to a hook below the instrument panel.

Seaplane Preparation / Part 1 of 5

Image

My original reason for building an airplane was to someday have it on floats. The construction plans do not provide any information specific for a float conversion so I had to research this myself.  During the early fuselage construction phase I visited with Larry Bauer who built a superb experimental seaplane pictured above.  Larry’s airplane is very similar to mine and uses the same Clamar amphibious floats that I would like to use someday. My visit with Larry was very useful in understanding how the floats are attached, rigged and controlled and in the next four posts I will describe the early airframe modifications that will later be used for transforming my taildragger to an amphibious seaplane.