Modifications

04-26-2009

There are builders who believe the original Cozy plans are "perfect" as-is, even sacred, in a way. There are builders who see the Cozy as something malleable, that can be adjusted to fit new times and needs. I'm one of the latter. The original Cozy design is actually around 30 years old, more if you count the Cozy III and Long-EZ that the MKIV is based on. A lot has happened since then!

Major Changes:

Mazda Rotary Engine

Aircraft engines are a mess. Seriously. A 40-year-old, used, carburetor-driven engine can cost more than a brand-new car! Parts and maintenance are also expensive. And don't get me started on add-ons. The price of a turbo, which in a car is a relatively minor upgrade?

I am installing a Mazda rotary 13BT engine, a 2-rotor turbocharged Wankel. This engine has very few moving parts and has proved reliable over the past decades. Because it uses a high-pressure fuel injection system, fuel plumbing is somewhat different from the plans, and I need a redrive, engine mount, and cooling system. For the most part, I will be emulating John Slade's installation. I've been fortunate enough to share a hangar with him for the past year, and I'll be able to leverage some of his experience in my own installation.

By the way... power? One day I flew with John in his Cozy, Slick Kitten. He gave me the takeoff, and I did what you do in any other aircraft - I floored the throttle. Imagine my shock when he pulled back on the throttle - I was giving it too much! Slick Kitten climbs like a rocket. It's hard to imagine a Cozy any other way.

Forward-Hinged Canopy (and Retractable Step)

I expect to regularly fly with a passenger, and wasn't very impressed with the side-opening canopy. It's a constant safety issue with many builder stories of unlatched canopies becoming a risk factor at take-off. It's also a hassle if you want to get in or out, or want to get something from the cabin, and you happen to the on the wrong side of the plane!

I installed a forward-hinged canopy using two car trunk hinges with built-in gas struts. They were designed for a luxury car with a heavy trunk, and easily support the weight of my canopy. To attach it, I added reinforcements for the attach bolts, and carbon fiber for stiffness to keep the canopy from swaying as it's lifted or lowered. The finished assembly looks and works great, and I'm quite pleased with it.

I also installed retractable steps on both sides of the fuselage. These are nothing more than solid rods in tubes with a pin inside the canopy to move them in and out - very much like door latches, actually. This provides a lower drag, more durable solution than the plans step, and also provides a step on both sides of the fuselage.

Larger Windows, Higher Canopy and Turtleback

I'm one of those uncomfortably tall Cozy builders - only 6 feet tall, actually, but all torso, not legs. I feel very penned in by the canopy in other builders' planes, so much so that in John's I actually fly without a seat cushion just to gain an inch or so of extra room. I've also had the opportunity to fly in the back seat of a Cozy (thanks to Marc Zeitlin, who took me to Maine to visit another prospective builder), and I was definitely not impressed. I think the designers thought of this the way car designers think of third-row seating in some small SUVs. It looks like a seat, but really it's a trunk - nobody actually sits there!

I've done three things to improve this situation. First, I have larger windows for the rear passengers to improve their visibility. Second, I lifted my turtleback nearly 2 inches when I installed it. Third, I spread it slightly wider than plans to give more feeling of headroom. This makes for a taller, flatter canopy, and a different look and feel. There is a drag penalty for this, but not much, and certainly nothing my engine can't overcome.

Forward-Swept Strakes

Minor Changes:

Electric Trim, Speed Brake, and Nose Gear Retract

Larger Nose Hatches

Car Seat Head Rests

Lucubration Project Pages