Review of the EXI 250 by mycoolheli.com

EXI 250 Review

Click here to view the EXI 250 CF Product page at Xheli

Click here for the EXI 250 thread on RCGROUPS.COM

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Video of an EXI 250 Review

This helicopter is small and yet fast for it's size. It can still do aerobatics, fly inverted and has a pretty decent roll rate. Run a 3S 800mAh 25-30C (20C is fine for hovering and basic forward flight) battery with it and your CG will be perfect. You need an 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.

Mechanical Setup:

Like 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 should 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 stuck, 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 have 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.

Tail:
This 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 gyro 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.

The Tail 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 dry rot..

Head:
Some 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 replacing the feathering shaft with Align during the build process. I continue to fly it with the EXI replacement shaft.

Parts:
The 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 mid 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).