In the last Home Shop Machinist was the first part of a series to construct a model gas engine with electrically operated valves. Although I didn't see it at the Cabin Fever Model Show this year, I've seen it previously and heard it run. The valves are operated by electrical solenoids controlled by a computer. This eliminates the entire valve train and allows the computer to optimize valve timing for the rpm and load on the engine. This allows an "electronic throttle" whereby the engine power can be varied by the computer rather than with a butterfly valve in the carb or air duct.

This innovation won't improve our aircraft engines which are already optimized to operate at a specific speed and power level but for our cars, which have a wide range of operating demands, this technology represents the ultimate. It's been talked about for over 20 years but it isn't here yet. Of course, neither are the ceramic coated pistons, combustion chambers, and valves either; at least in widespread use. ( In the April Kitplanes on page 43, LyCon says it coats piston crowns with ceramics. Others also do so but it hasn't become mainstream).

I know, my van has variable valve timing. Toyota, Honda, and others have developed this over the last 5-6 years but these are hydraulically actuated camshaft shifting devices, not an independently variable optimized system. Sort of like the two speed Hamilton Standard prop vs the Hydramatic or the GM fuel injection of the 80's, read injection carb, vs the multipoint fuel injection of the imports. Non the less, I consistently get 25 mpg on highway trips with the van.

Anyway, ultimately your car computer will control ignition, fuel flow, and valve timing, thereby allowing optimization of engine parameters for any load/speed combination. Thus we will get better performance and fuel mileage.

"Beware of unfinished projects "

This should be the subject of a FAA publication if is not one already. I thought that I uncovered most of what was done by others, but when I was setting up the drag/antidrag wires I found the steel that was supplied too easy to thread. This probably meant that it was not 4130, but I found a receipt for the right material. Fortunately, the fuselage and motor mount were done right by Richard Lauzon dba Weld-Tech. I am glad that nothing was covered to the point that I would have to tear things up just for peace of mind. The traditional wing construction of the Hatz is very different from the Cygnet, which had plywood 3 piece ribs and no internal bracing. The Hatz wing went together very quickly (ribs were made already) but fabricating the fittings and bracing took many hours. Now I only have to figure out how to accommodate a 3/16" error in the spar spacing so the wings will fit the fuselage (plans shrink!).

The members of the Hatz forum are very knowledgeable, and answer my questions in short order.

Makelan Corp, who sells plans and materials for a refined Hatz, the "Classic" has a photo cd with at least 400 images of details. The tank design that they use is exactly what I planned on using to up the quantity to 3 hours. It is comforting to see that my plan works. I also bought a set of evaluation plans which are reduced to 8 1/2 x 11. These are good enough for getting general ideas. Reinforcing of the wing walk area is one area where I like the "Classic" method. I am sure more details that I will use will come up. Their treatment of ailerons looks really nice, aluminum with corrugations ala Waco.

Chapter 891 (Sussex) is having a Fly-In at Sussex Airport (FWN) June 4 & 5. For info see eaa891.org or call Robert Hewitt at 973 725 1210.