Our reason for using this part was to neatly and efficiently redirect
the exhaust back to the stock muffler that we mounted into the
bottom center recessed opening at the nose of the fuselage. We
fitted our stock muffler with an aluminum exhaust diverter made by
MAC's Products - part number #9114. This diverter holds up to the
high heat generated at the muffler by 4-stroke engines.
This
set-up also maintains the nice lines of the airplane and has proven
to be outstanding in our own Waco models.
We can highly
recommend duplicating it on your own Waco SRE.
a) As received the Saito Flex Header comes with a
pre-installed pressure tap tube, located toward its muffler end.
Because we wanted to use the pre-installed pressure tap already
in place on the stock Saito muffler, this tube had to be sealed. To
do this we trimmed off the pressure tube and filled the small hole
with solder, effectively sealing the pipe.
b) Disconnect the throttle linkage and remove the engine
from the mount arms. Install one of the header nuts that came with
the engine exhaust system and thread it fully in place onto the flex
tube header. Thread the header in place into the engine exhaust
port and firmly tighten the jam nut, locking the flex pipe in place in
the engine.
measurement was 1-5/16”). Reinstall the cowl onto the fuselage.
c) Lay a ruler on the side of the fuselage, centered over the
trim tape. From the back edge of the cowl, measure forward to the
measurement you just recorded. Mark this point on the cowl, using
a sharp, pointed instrument. Remove the cowl and at the mark just
made, drill a 3/32” dia. hole through the cowl. Remove the trim
tape pieces from the fuselage and reinstall the cowl onto the
fuselage.
d) You should now be able to see the center of the fueling
valve through the small hole just drilled in the cowl. It might be a
little off center but this is easily corrected in a moment. The Du-Bro
fueling probe that comes with the valve itself, requires a 1/4" hole
diameter to fit fully into the valve. Use a pencil and a circle guide
to draw a 1/4" dia. hole directly onto the cowl - corrected as
needed to adjust for any off center issues. Use a Dremel
®
Tool with
a tapered sanding bit to open up the hole in the cowl to the 1/4"
outline just drawn. Mount the cowl and check your work. The
fueling opening in the cowl should now be directly over the center
of the fueling valve and the fuel probe should fit into and out of it
easily.
❑
6) It is at this point that you have to give consideration to any
unique cowl opening(s) that may be required for your particular
engine and muffler.
If you are using a 2-stroke engine with a
conventional muffler set-up, you will most definitely have to create
openings in the fiberglass cowl for its clearance. These openings
should be made carefully and be kept to a minimum. If you are
using a 4-stroke engine with a stock header and muffler, you will
also have to create an opening for the muffler. Also, consideration
has to be given to the glow plug and how you will access it with a
glow driver.
We suggest planning these openings carefully,
marking them with a non-permanent marker and using a Dremel
®
Tool with sanding bits to make them as neat as possible. If you
have chosen to use the Saito 1.00 four-stroke engine, as shown in
this manual, the following steps will show you how to completely
eliminate the need for muffler openings in the cowl.
❑
7) For our Saito
1.00 installation, we
chose to use a Saito
7” Flex Tube Header
- part number:
SAI182TD1112.
23
Modeler’s Note: We obtained two Saito 1.00 engines for our
Waco models and discovered that apparently Saito produced
these engines with two different muffler types. One of these
muffler types is the constant diameter canister type with its
header location squarely at one end and the exhaust outlet
squarely at the opposite end. The other muffler type is cast
aluminum with a tapered shape. This muffler has a heavily
offset header location and its exhaust outlet squarely in the
center of the opposite end. The Flex Tube Header installation
shown in this manual works with either of these muffler types.