The Engine Shop - 2004/01
NEW AND TRULY practicable advances in model-airplane engines
don’t come along often. Some major advances I remember are when
model “diesels” were developed in Europe during the World War II
years, when the glow plug came out in 1948, and when the first 1⁄2A
engines came out the year after that.
The Engine Shop 2003/01
IN the prevIouS column I discussed catalysis: how some
substances (such as zinc) promote reactions between other chemicals
without being chemically affected themselves. I mentioned an
experience with a brass fuel-tank clunk weight that catalyzed glow
fuel into acetic acid (a potent rust inducer!) and told about how a diecast
zinc alloy model engine part once converted a jarful of “cleaning
solvent methanol” into acid, which then completely ate away the
casting.
The Engine Shop - 2001/05
DeveLoPMentS ContInue in CO2 power! Stefan
Gasparin has just released a “universal throttle” control, which
works with any CO2 motor (except for the very smallest, such as
the Brown A-23).
With this universal throttle, someone with an original 1947
OK CO2 motor could use it (equipped with a modern refillable
CO2 tank) to power an Old-Timer CO2 Free Flight (FF) model in
“RC Assist mode.”
This throttle control (available from the Blacksheep model club,
21410 Nashville St., Chatsworth CA 91311; Tel.: [818] 718-1685) is
somewhat expensive, but the drawing shows its intricate
construction. Considering it weighs only 2.5 grams (the same as a
dime), I can understand the reason for its price.
The Engine Shop - 2001/03
FrED rEEsE died last November. He was one of America’s most
prolific designers of small Radio Control (RC) models. For the past
few years, Fred was an associate of Thunder Tiger in the
development of its line of small RC engines.
In his last communication with me, Fred solved a pesky starting
problem with the smaller Thunder Tigers.
“ … the .07 needs to be wet to start. I prime the engine by
placing a finger over the exhaust outlet on the muffler and turning
the engine over. If using an electric starter, I just cover the exhaust
for a second while spinning, and it will fire instantly.
“I had a terrible time starting the engine when new until I tried this
method. Actually, I could not get it started at all until I primed it this
way, which uses the trapped pressure in the muffler to push fuel into
the engine. Mine will hand-start easily now; it just needs to be wet.”
I suffered the same difficult-starting problem with a Thunder
Tiger .10, but Fred Reese’s priming technique works as well for me
on that engine as it did for his .07.
The Engine Shop - 2001/01
For More than 60 years, one particular size of model engine
has been almost an orphan, at least in competition classifications:
the .10 displacement engine.
When the Academy of Model Aeronautics (AMA) established
“classes” of model-engine sizes in the 1930s, it set the upper limit of
Class A at .199 cubic inches. That was purely an arbitrary decision—
a “best guess” on someone’s part as to what would be a good
dividing line to separate “little engines” from the “midsize” Class B
engines (.200 through .299).
At the time, that probably didn’t seem important. Most gas model
flying—all of it Free Flight (FF) then—was done with Class C
engines (.300 and upward). Few engines on the model market were
much less than .36 displacement.
