From the Radio Control Club of Detroit, Clinton Township, Michigan
A Secure Silicone Exhaust Deflector
by Noel Hunt
Click the thumbnails below to
enlarge the photos.
 
The newer breed of engines are
great at retaining the fuel and oil in the engine,
discharging it only from the exhaust outlet.
Unfortunately, that outlet often discharges onto a
fuselage side, or a wing surface, and so we still
need to clean the aircraft at the end of the day’s
flying. Such was the case with my Norvel .40. I
tried the standard silicone exhaust deflectors a
couple of times and they did keep the airplane
clean, but only for a flight or two. Then the
airplane would land with the deflector missing and
sludge on the fuselage and wing. Chances of finding
the deflectors? Zero!
I devised a neat, simple, inexpensive, solution that
works. And it will work on any muffler that has a
smooth muffler outlet. (Some of the manufacturers
are now including a zip-tie groove in the outlet
that serves the same purpose.) I have since flown
the Norvel with the same deflector for more than 50
flights. So I modified a few more mufflers and took
pictures as I did so.
Step One: What you’ll need:
• Appropriate size silicone exhaust deflector for
your muffler, and zip-ties.
• JB Weld.
• Isopropyl alcohol and masking tape.
• Paper towels.
• Short length of 16 or 18-gauge solid copper bell
wire.
• Side cutters.
Step Two: Thoroughly clean the muffler outlet
using a clean piece of paper towel and isopropyl
alcohol. Do this three or four times to ensure all
the oil is removed.
Step Three: Wrap the copper wire around the
muffler outlet about twice to get a consistent
radius for at least one turn. Remove from the outlet
and decrease the radius slightly for a snug fit on
the outlet. (Or you can wind it around something
that has a slightly smaller diameter—I used an
Exacto knife handle.) Cut the ends so you have just
one coil and the ends butt against each other. If it
does not come out just right, repeat until you get a
good fitting copper “o-ring.” (Pictures One and
Two.)
Step Four: Cut a thin strip of masking tape
and apply it to the muffler outlet, leaving only
about ¼ inch of the outlet unmasked. Include a
fold-over at the masking tape’s free end, to
facilitate easy removal. (Picture 3.)
Step Five: Mix some JB Weld on a clean piece
of disposable card. Apply a thin layer to the ¼ inch
of exposed muffler outlet. Slide the copper o-ring
onto the outlet and center (about 1/8 inch from the
end). Apply more JB Weld to the outside of the
o-ring. (Picture Four.) Using a clean piece of paper
towel, wipe away most of the JB Weld. (Picture
Five.)
Step Six: Carefully remove the masking tape
while the JB Weld is still wet. This is where the
fold-over will help. (Picture Six.) Allow the JB
Weld to cure per the instructions. It is not like
30-minute epoxy; I give it 24 hours.
Step Seven: Install the silicone exhaust
deflector on the muffler outlet and retain it in
place with the zip-tie on the “north side” of the
new copper o-ring.
These days my airplane requires very little
cleaning, at least from oil residue. About all I
clean is mud splash when the field is soggy. That’s
going to be a tougher problem to solve. Mmm! On
second thought, the Avistar might look good with
wheel pants! Q
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