1978, before entering the U.S. Air Force, I built a Dumas Pay'N Pak radio controlled
hydroplane (modeled after the Pride of Pay'n Pak unlimited hydroplane). Sadly, this
is the only known existing photograph of my Pay'N Pak unlimited hydroplane. As shown
in the photo to the right, it is hanging in my room in the barracks at Robins Air
Force Base, Georgia (c.1980). The cowling & rear airfoil assembly is not attached
for some reason, so you can see the water-cooled engine, flywheel, part of the drive
shaft, rudder assembly on the transom, and the plywood hatch over the radio compartment.
Like most of my other R/C models, it sported a Futaba radio.
not simple, as I remember it. Interlocking plywood bulkhead members formed the basic
inner structure, and the plywood sheeting was epoxied on the bottom, sides, and
top. Forming and holding all the compound curves while the epoxy cured without allowing
a twist to be built in was a real challenge. The transom is the only totally flat
piece on the entire craft. I coated the entire thing with fiberglass resin and managed
to get a very smooth and shiny finish using an automotive lacquer paint (sprayed
by my friend, Jerry Flynn).
I cannot recall which engine I used, but it was a marine type with the water-cooled
head. To start the beast, I used a piece of string about 1/8" in diameter, threaded
it under the grooved flywheel, and gave it a tug. Once the engine was broken in,
starting was not so bad. I built it shortly before going into the USAF, and then
on a trip home, brought it back with me to the barracks. The Dumas Pay'N Pak ran
a few times in a lake somewhere around Macon, Georgia. After the war (that's a joke),
it was run a few times in the Severn River in Annapolis, Maryland. Sometime before
packing up to move to Vermont, I sold my Pay'N Pak to a local guy who answered an
ad I placed in the newspaper. Also shown are my
DuBro Tri-Star helicopter and
an Airtronics Aquila RC glider with ABS plastic
A brushless motor would really make the Pay'N Pak fly, and without the hassle
of getting the engine started.
Dumas still offers the
for sale on their website for $110 (it was only $55 in 2013). The running hardware
kit costs an additional $95 ($43 in 2013).
Length: 30 inches
Beam: 13-1/2 inches
Power: .20 or 3.5cc gas marine engine
Running Hardware: #2322 solid shaft drive line w/1/4-28 size engine shaft