Paul,

Last week I manage to take some pictures of the jigs
used for making
identical housings based on this cut off test
housing.These jigs
with
positioning dowels and through bolts have evolve to
accept casting
plates for the DEVCON epoxy, orhardened
steelplates with drill
inserts to drill the hold down stud holes for the
throttle. Ditto a
plate to drill thefuel injector bore holes
and the injector hold
down
plate studs. As of today these jigsalso
havequick release air hose
connectors for leak testing.

Pict . 007The p-portfinal step cutter
I made installed in the end
mill. It is set at a 56.3 mm OD.Works like a
champ.Not shown is
the
P-port insert 56 mm OD 50 mm IDwhich has
O-ring grooves cuts to seal
on the inner and outer sides of the water
chamber.It of course slips
into the port hole. No welding needed and is
removable, inspectable
and
changeable. Held there by the throttle Plate.
Throttle to be fastened
to the housing by four M5 studs that also hold on
the intake manifold.

Pict, 080. My design of alow profile low
restriction throttle.
Why?
In my application slide throttles are cumbersome and
won't get me up
close and personal to the p-port as I would prefer.
Hence the throttle
opening isover sizedto compensate for
the 1.5mm SUS 304
thickness of
the throttle plate.It is 53 mm ID. The
throttle plates (two needed
and two to screw up trying) are laser cut ellispes,
slotted and to be
TIG spot welded in situ to the slotted 6 mm
Stainless 303 shafts.
Center
hole is for jig positioning. 303 on shaft
is much easier to machine a
1.5mm slot into while the materialstill has
good corrosion
resistance.
Shafts shown are notprofiled yet
for minimalair resistance in
WOT.
Ditto thethrottle platesbut they will
be.One shaft will not
protrude from the throttle plate.The other to
the central housing
spring and cam location. Good advise courtesy
ofKinsler. Now looking
into baked on teflon paint coatings to see if they
have any measurable
merit in lowering air resistance in the intake
manifold parts.It
does
on prop blades.

Bearings are NTN BEAREE a tough fluorcarbon plastic
which is harder
but
more slippery than Teflon. I believe this is the
same material used in
motorcycle throttles. This materialhas been
tested on our wind
generator swing tail rudders for three years in the
field.These
tests
are equal to several millionswing cycles with
no failures, at least
not in the bearing.Earlier tails had to be
strengthened as they got
beat up in the winds.Google "Airdolpin wind
turbine" to see it in
action.Now on sale in USA.

Other updates as they happen.The next
challenge is to cast a near
perfect finished epoxy face on to a new housing and
have it free of
inclusions.That requires a liquid AL. DEVECON
and application of a
vibrator.

Doug in Japan

How about applying vacuum?

Chris Cosman

Hi Chris,

Good idea in theory but the forms would need to be a
tight fit on the
various curved surfaces.The force of gravity is
adequate and the end
of the pour will be on the top edge of the casting which is
easy to
level with a hand dremel tool.

One trick is to pour the liquid down a rod inserted
into the cavity.
Then a use a large industrialvibrator or the type
they sell for
shoulder stiffness for a few seconds and any bubble will
just pop to the
surface.

Doug in Japan

Also consider pulling a vacuum on this assembly. I have done this
with with silicon potting compound on a small pneumatic manifold.
The end result is a bubble free, high gloss finish.

Erik Wahlstrom


Erik, Chris

OK the idea of a mirrow smooth finish is intriguing but not necessary
because one pass of the end mill before boring the port holes will take
careof small ripples Because of the angular shape Iwould still have
to do two pours and to ensure no air could be pulled in from the
abundant perimeter joint location I would have to seal them with silicon
sealer first. And that stuff is a pain to remove assuming I can even get
the mold plate off.The upper and lower edge of the epoxy build-up area
is a complex curveshapewhich is why I wanted to pour FROM them.
IE, those areas would be facing upwards during pouring.

Doug in Japan