Legal Part 103 single-seat trike as flying boat (like Polaris or Sea Trike)?

Mon, Feb 16 2015 02:32pm CST 1
Scott Hardin
Scott Hardin
1 Posts
I am searching for an inexpensive low-n-slow Part 103 one-seater Trike with floats--no x-country, usage in favorable wind conditions only. Looking at the non-103 two-seater "flying boats" from Polaris and Sea Trike from the '80s and '90s gave me a crazy idea... why not use an inflatable boat with planing hull on a legal Part 103 trike? Here's an example configuration of what I mean:

Simple trike (e.g. without faring):

Ace Magic Laser


??something with more load capacity to handle additional weight of boat hull??

Light, powerful motor:

Simonini Victor 1 Plus (6 HP more and 40 lbs less than Rotax 447 DC)

Inflatable Boat:

PHP-310 Performance Air Floor Inflatable from West Marine
(73 lbs + rigging and small rudder)

Certainly, the trike frame, wing and motor will need to be selected to handle the additional weight of the boat in order to have enough MTOW allowance, but it should be no problem meeting the legal weight limits of Part 103.

Of course, the manufacturers of the two-seaters claimed on their websites that their designs are safe and superior to regular straight floats. On the other hand, there are opinions in the Internet that these trike boats are too top heavy and unstable [e.g.:]. There's even a crash video on youtube [], but that looks more like pilot error than general instability--the way he came down would have trashed just about any trike, regardless of the undercarriage and terrain.

Does anyone have first-hand experience with the safety of these flying boats? With the weight of the wing and motor up so high, how is the stability when the boat starts rocking? Is it possible to get the weight of the motor and pilot low enough for it to be safe without sacrificing visibility by having the pilot too low in the boat?

It is strange that these Polaris and Sea Trikes seem to have all but disappeared from the market after the brief popularity in the '80s and '90s. Did they die off because of safety issues? My suspicion is that they stopped being produced because the manufacturers didn't want to bother with the certification for S-LSA and the fiberglass/metal hulls being used back then were too heavy for legal Part 103 one-seaters.

Assuming that safety is not the issue, the new high-pressure inflatable floors being readily available may make this an interesting alternative. The PHP-310 from West Marine is only about $1400, which is considerably cheaper and also lighter than a set of floats. As a comparison, the RIB-310 Double Floor Rigid Inflatable from West Marine costs $3000 and weighs in at 130 lbs. The planing characteristics of the PHP-310 are still supposed to be pretty good--I read claims that it only takes 5 HP for 1 person.

So, is this a clever idea or is it something worthy of a Darwin award?
Thu, Oct 22 2015 07:56pm CDT 2
jerry jaksha
jerry jaksha
10 Posts
I am also interested in adding flotation to my 103 skycycle.
My inclination is to use two inflatable 10-12"dia. x 10' pontoons (catamaran ) . Cats are very stable if the floats are near the wheels, they have less drag than monohulls, and- who needs a boat when your seat is 2' above the water?

A kickstart backpack cat kayak company in Europe has a 6# (yes 6# kayak) prototype. We would need a frame to keep the pontoons straight, and framework to attach, but little else, if we can break away from the water suction. Seems like a very reasonable safety setup for flying over water even if you never could take off. At least you could land without doing a summersault and sinking.
The kickstarter prototype has a strong fabric shell and airtight tubes iniside, like kite board kites.
I would be interested in talking to anyone who would like to develop a lightweight tubular water landing rig.

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