EXI 250 Review
here to view the EXI 250 CF at Xheli
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an EXI 250 Review
helicopter is small and yet fast for it's size. It can still do
aerobatics, fly inverted and has a pretty decent roll rate.
a 3S 800mAh 25-30C (20C is fine for hovering and basic
flight) battery with it and your CG will be perfect. You need
18-25A ESC and a 3200-4200kv motor. It is fitted for typical micro 9g
servos (just like a 450). One difference between the EXI 250 and the
Align 250 is the bottom frame has the skids integral to it. You can
dremmel this and drill holes if you wish to use Align or Gaui 200
skids, but the EXI bottom plate is very inexpensive anyway.
any ARF heli kit, you MUST re-loctite all the metal to metal fastiners.
Indluding the head and tail screws. This is a must and you
do this for your own safety and the safety of others. This is no
different than what MUST do to other helis you might get from other
manufaturers other than EXI. If you find a screw is really
heat it up with a soldering iron tip to loosen the loctite. On the EXI
250, you have to be very careful not to over tighten or turn the screw
too hard. They are very small threads (1.6mm). You can easily snap the
heads off. In general, if they are tight, I leave them on. Use only a
single drop of blue loctite. Be careful not to lose washers. Especially
on the maingear. The kit comes with spare fastiners as well as the 3
types of fastiner drivers you will need. The kit does not
flybar weights, you can add your own RC airplane wheel collars or just
put 2-3 2mm nuts on the ends by the flybar paddles and glue them
lightly with CA or just let centrifugal forces keep them out.
is the most difficult part of the helicopter. Even the Align 250 will
suffer from tail stability. Some things to consider is to use a very
fast digital 9g tail servo (.08s or faster). Use a good tail
as well. I put a logitech 2100 on mine but others have had very good
sucess with the Align GP750 Gyro on the 250.
A couple things that
help with the tail is to change out the Tail slider with an Align and
the tail control arm with an Align. The tail slider on the EXI 250 has
a ball link that is too small. It has too much slop. The control arm is
longer on one end that yields more travel than an Align which makes you
lose servo resolution.
belts on at least the initial production run would rip apart in mid
flight. I purchased an Align 250 belta and an EXI 250 belt and they
seemed identical. The original belt seemed dry rot and would crack if I
bent it too much, but the replacement EXI 250 belt did not seem to be
people have complained about the
Swash not having a good center bearing. An Align 250 Swash is $25 or
sometimes comes on sale at Readyheli or other sources. Some people have
also had complaints of the feathering shaft (Spindle) snapping in
flight or while working on it. Mine snapped apart on the first crash as
it hit the ground when the belt failed. I used a replacement EXI shaft
and it did not snap, but properly bent on crash #2 as I dumbthumbed it
low level inverted flying. Some people are immediatly
the feathering shaft with Align during the build process. I continue to
fly it with the EXI replacement shaft.
spare parts at Xheli for the EXI 250 are very inexpensive. So far, no
one has noticed any of the differences in crash components vs. Align
for fit. There were reports of feathering shafts splitting in
flight or during crashes as mentioned above but I noticed that the
replacement parts for the shafts seem to
be better than the original production run feathering shafts so I
believe the quality issues are closed.
The kit comes with plastic blades which are fine for hoving and maiden
but nexpensive Fiberglass blades are good for this
helicopter, especially at the beginning when your getting used to it.
But Carbon Fiber blades will really show what this helicopter is
capable of as well as have less tracking inconsistances compared to
fiberglass. The EXI 250 will support 205mm
blades (Xheli and Hobbypartz sell them).