Wally Minto's Wonder Wheel
by E. F. Lindsley
Popular Science, March 1976
Wally Minto's eyes twinkled. "Now that you've got your pictures of the
serious stuff, I want to show you our latest engine. It's at least 85%
effecient, never wears out, requires no fuel or maintenance, costs very
little, and should have been invented 100 years ago."
I'd just finished shooting pictures os Minto's solar-powered, Freon
engine/generator set (P.S. Feb 1976) and I wasn't quite sure if he was
kidding about this newest engine. Four used propane bottles were
hose-clamped to the ends of two pieces of aluminum angle, each about
four feet long. The angles crossed at 90 degrees at the center and
were mounted on a central hub like a skinny four-blade windmill with
bottles to swing in the breeze. Each bottle was connected to its mate
on the opposite end of the angle with steel brake-line tubing. Under
the rig's support was a tank of the type used to locate leaks in an
While I gazed in disbelief, Wally explained how his incredible power
wheel works (see diagram above) [text is included at the end of this
A few weeks later I again visited the Kinetics lab. By then the
propane bottles had evolved into 12 containers of steel pipe welded
into a polygon. The principle remained the same. I watched as Wally
opened the valve to let in a trickle of water from solar panels on the
roof of his parking shed. The water temperature was 155 degrees F.
Almost imperceptibly, the wheel started to turn. The speed picked up a
bit and I timed a revolution -- about one rpm. Minto noted my
misgivings. "Try holding onto the shaft," he said. I grabbed the
shaft firmly -- it was if I'd tried to stop some eerie, irresistible
force: no sound, no evidence of power, just pure twist.
"Picture one 200 feet in diameter," he said. This time my mind
boggled. Such a rig might hoist the pyramids.
Wally doesn't expect industrialized nations to scramble for his wheel,
and he isn't selling anything. He's donating it as a "gift to the
world" and expects it will be used in underdeveloped, energy short
For example, a practical 33 ft. diameter wheel running on a temperature
difference of as little as 3.5 degrees F and producing several
horsepower could pump irrigation water, grind grain, or saw wood. The
materials could be scrap pipe, and no machining or skills are needed to
build it. Several low-boiling materials might be used, but propane or
R-12 may be best.
Minto estimates a slightly larger (40 ft.) wheel with 14 pairs of
one-ft. by 4.5 ft. containers would provide 10,240 ft/lb of work per
container as each 269 lb of liquid responds to gravity through a 20 ft
level arm. At only one rpm this is 8.69 hp; not spectacular, but low
cost and capable of running steadily for generations. The slow
rotational speed can be stepped up to whatever is needed, just as with
the old-time waterwheels.
No fuel would be needed in many cases. The temperature difference
required between the liquid on the bottom and the top occurs naturally
in many situations: water and air, light and shade, etc.
Minto has outlined construction details in a two-sheet paper entitled
"The Minto Wheel." There are no restrictions on building or
experimenting with the wheel.
Sun Power Systems, Inc.