Building an Aventura II




If you've ever thought about building an ultralight, or if you have built one and are interested in how other people have done it, the following pages show my experience as I build an Aventura II seaplane. My name is Steve Bensinger; I live in the Lakeland, Florida area, and I've been flying ultralights since 1984. The Aventura is the third plane I've built; the first one was a Teratorn Tierra (now sold by Golden Circle and called the T-Bird), and the second was a RANS S-4 Coyote.

Note: After seven years of having fun with this plane, it was time for me to move on. I've since built a Hawk II Arrow, which won Best Ultralight Construction Kit at Sun N Fun 2003, Best Ultralight Trainer at Sun N Fun 2004, Outstanding Fixed Wing at Sun N Fun 2005, Grand Champion at the 2005 CGS Hawk Fly-in, and Best Construction Kit at Sun N Fun 2006 (see it at my "Building a Hawk II Arrow" web site). I have also built a single seat Hawk Sport, which won Outstanding Fixed Wing Ultralight at Sun N Fun 2004, and with which I competed in the World Microlight Championships in England in 2003, took 2nd place in the US Ultralight Championships in 2004, and took 1st place in the US Microlight Champs in 2006 (see it here). The Aventura was sold 4/14/2005.

Aero Adventure of Rockledge, Florida USA manufactures the Aventura line of light single and two seat amphibians.

The following information defines what ultralights are in the USA, and gives a little background on ultralight construction and powerplant choices. Or if you like, you can skip the fluff and start building!

Definition of an Ultralight

Since this aircraft has two seats, in the USA it is not an ultralight, as defined by the Federal Aviation Administration. For more information on the rules pertaining to ultralights in the USA check out the Federal Aviation Regulations, Part 103. They are available at Jon Steiger's excellent Ultralight Home Page.

Someone wishing to fly this type of aircraft in the United States has two choices:

Note that in many other countries this plane would be considered an "Advanced Microlight."

Ultralight Design

This plane's design and construction use the same materials and design concepts as many current ultralight designs. Except for the boat hull much of what you see here is very similar to other popular designs from RANS (the Coyote and Airaile models), CGS (the Hawk), Flightstar, Quicksilver, and many others.


This airframe of this kit consists of aircraft quality aluminum tubing and fittings bolted and pop-riveted together using aircraft-grade fasteners. The wing and control surfaces are covered with heavy-duty dacron cloth, much like what is used with boat sails. The hull on this plane is actually Kevlar, used instead of Fiberglas to save weight.

The Engine

The engine used on this plane is a 65HP, two-cycle, two-cylinder, water-cooled powerplant sold by Rotax (a subsidiary of Bombardier) of Austria. It incorporates two Bing slide-type carburetors, a dual CDI ignition system (two spark plugs per cylinder), and a gear reduction system at a ratio of 2.58:1 to drive the prop. This engine has a pull starter, though electric starters can be fitted.

Does Bombardier sound familiar? Originally these engines were designed to drive water pumps, then were redesigned for snowmobiles, and lately are being used in personal watercraft. The engine used here has been specifically designed by Rotax for use in light aircraft. They have a very high power-to-weight ratio, mostly due to the fact that they produce power on every piston stroke, as opposed to four-cycle engines which produce power on every other stroke.

There has always been concern about the reliability of two-cycle engines because they work harder than a comparable four-cycle. However, with proper maintenance they can be very reliable. This means you have to either be knowledgeable about your engine, or have the money to pay somebody else to maintain it. These engines do not have to be babied, but they do need to be properly maintained, or you will have an engine failure. Of course, that applies to any engine!

Enough Already! Let's start building!

Other Aventura Sites

Iflyamphib's (Jim Ratte's) Aventura Page

Flying FOOLZ Web Site

An ultralight club for Southeast Michigan and Northwest Ohio.


Aero Sports Connection


United States Ultralight Association


Experimental Aircraft Association


Seaplane Pilots Association

You are visitor numbersince January 9, 1997

This site was selected as Ultralight Flyer Online's "Pick of the Week" for January 22-28, 1997.

Do you have any questions or comments? Email me!

 Apple Computer's Web Site


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  Copyright 1997-2000 Steve Bensinger

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