Fans
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Fans |
 Arizona
Research & Machine (2-28-3) - I was asked to
check it out so here is what I found out. The fan sells
for $30 and looks like a nice one. There is a 30 and 50
version, I tried the 50, the only difference is the 50
version has the extended hub for the longer crankshaft on
the larger engine. The unique thing about this fan is the
curve on the ends of the blades. The blades are a
straight orientation like the stock fan. I installed this
a TT50 engine and checked for runout on the outside
surface and top of the hub area. The outside was off by 0.0015"
which is fine. The top surface was right on. Next to test
the centering of the inside of the hub I placed a clutch
in the hub (no bolts). I put the dial point indicator on
the clutch and held the clutch in one place while
rotating the fan under it. This came up with bad results
:-( The center hole of the hub was off by 0.012"
That is way too much! Hopefully not all of the fans made
are like this but it is something you need to check. This
would cause foaming in the tank if left like this. I
still needed to test if this fan had any benefit as far
as extra airflow so I had to fix the first problem. I
grinded on the inside of the hub to give me a little room
to position the clutch. It does seem that the bolt holes
for the clutch are good, it was just the inside of the
hub that was off soo much. Note: Not only do the bolt
holes have to be the same distance from center but also
if you draw a line from them both the line needs to pass
through the center of the hub. So I ended up with the fan
and clutch installed and proceeded to check airflow. At
idle (and with the same engine rpm) I had my Raptor #1
and #4 side by side. Feeling of the airflow around the
head I detected no difference. Maybe in theory it works
better in flight but I did not notice a difference either.
To sum it up I will stick with the stock fan. It maybe
plastic, but the one that came with my 50 conversion kit
has 0.000" runout! And the bolt holes are right on
also (well one set is off by 0.003" but the other is
right on). And my stock one weighs less. Rick's R/C
- I bought a metal fan for $30 from Ron Lund (Ricks R/C). Very nice
looking! The blades are curved to bring in more air and
the center has a smaller diameter to allow better air
flow. Comes with a spacer to fit 46/50 size engines. I do
have a friend that said his was way off balance so be
sure to check yours before installing. I checked mine but
it was not off balance. It is tuff to check with my
Robart high point balance because the cones don't want to
seat correctly, but I did get a good check and I did not
have to correct the balance.  QuickUK
- RD-8 Raptor 46/50 fan. I bought this but have not tried
it yet. Manufacturing qualities look to be top notch! No
threads, it uses the collects to center it up. It also
has the top of the fan hub shaved for clutch shoe
clearance. It cost about $55 USD. It does cost a lot for
a fan but I wanted to test it out since I have heard from
others that said this was a very good fan to get. |