Product Review Page

Dynam eRazor 450 2.4Ghz version Review & Setup Guide

Note: much of what is documented here should carry over to the 250 model

January 2011 update:  This review was originally done on the original 2.4Ghz Transmitter when the Dynam eRazor was released. They are now shipping a revisze radio with the unit. I will try to make notes below to the differences.

Click here to view the Dynam eRazor at Xheli

Download the Dynam eRazor 450 Product manual from Dynam
Download the Dynam 40A ESC manual from Dynam
Download the Dynam GY192 Gyro manual from Dynam
Download the Dynam 2.4Ghz Radio Manual from Dynam (note, there are errors in this manual)
Download the Dynam 72mhz Racon X6 (LCD Version) Manual from Dynam

Initial impressions:
Resonably positive. I found one dip switch incorrectly positioned (Dip switch #1 PIT). Other than that, it looks (currently) like it's ready to fly with a little initial setup and tweeking.  It has a larger 2200mAh 3S and some other kits in it's class come with 1800mAh 3S packs. If I compare this to other helicopters in it's class (Belt CP, Blueray SE, Helimax AXE etc) I'd say it's towards the top in terms of what you get for the value. Compared to my Esky Belt CP, the eRazor 450 is better. The Blueray has it beat for upgradability and Align 450 compatibility, but the Dyam E-Razor has lots of metal on the head/tail unlike most helicopters in it's class. The one problem I see is parts availability. You are limited in where to get parts from. Unlike the EXI 450 line or Exceed Blueray, these parts don't really seem to be compatible with another brand of helicopter. So get spare parts when you order one if you decide on the eRazor.  It is solely due to parts availability that I do not recommend this helicopter unless you can see that Xheli has stock of spare parts and you order some upon initial purchase.

E-Razor Photo1  E-Razor Photo 2

Dynam eRazor 2.4Ghz Manual corrections (original Tx Manual)
Manual Errata:

Page 2:
 Left knob is NOT Gyro Sensitivity Kob, It is Rudder Mix (Revo Mix)
 Right knob is NOT Rudder mix (Revo Mix) it is gyro sensitivity (Gyro gain)

Page 7
 Note: Flipping dip switches 8,9,10 will NOT yeild LED color changes
 Section 7.2 Reverse adjustment (all outof wack, ignore this)
 Section 7.3 This is Dip 9 PLT/PIT
 Section 7.4 This is DIP 10 RUDD MIX/GYRO SENSE
 Section 7.5 This is DIP 8 EXP
 Section 7.5.3 V2 in EXP mode does not affect throttle, it affects swash mix.  This is JUST like a traditional SWASH AFR or SWASH mix. More CW on dial V2, the more cyclic roll you will have in both cyclic axis.

Dynam 40A ESC Manual corrections

Brake Setting
The beep sequence for setting the break is incorrect. When in the programming mode, you will hear 4 beeps first (not 5). Dropping the throttle when you FIRST hear those 4 beeps (2 low, 2 high pitch) that will toggle the Brake mode then initialize.
When you power up the Helicopter,it will beep either once, or twice, then beep 5 times slowly. That first beep of a single or double, tells you if the brake is on or off. You want it to beep twice, then 5 times slowly. That indicates Brake is off.


Mechanical observations:
The ESC was wire tied and made it hard to disconnect the motor so I could safely test it out and check pitch values in normal and idle up/3D mode.  Thus, I cut the wire ties to the ESC and the servo wire comming off the ESC to the RX and rotated the ESC 180 degrees. So the motor wires come out the front and the power/servo wires come out the back. I also routed the motor wires from the motor out the sides so that the esc bullet connectors are outside the frame.  (I'll post pictures in a day or so). I only needed to add a 1 turn on each blade's tracking linkage (long linkage to swash) in order to get 0 pitch at center stick in 3D/Idle up mode.  

One thing interesting is that the pinion is upside down because the maingear is so close to the motor vertically

Gyro is an MKS GY192 (relabeled as Detrum/Dynam). This gyro functions much like an Esky 704A gyro. It is installed with the lable facing sideways (never up , never down). For this helicopter and servo arrangement, the gyro is installed with Label facing RIGHT, Servo connector for the Tail servo facing back and wires comming out the front.  For the helicopter in this review, the writing on the label was upside down. If for some reason, you need to reverse it, you would rotate it so that the label is facing LEFT while still maintaining the servo wire to the Tail servo comming out the back. NOTE: I noticed the Xheli website photos for the gyro installatin did NOT match the gyro installation of my helicopter which I tested to verify it was functional.  You will Perform a Gyro bench test to verify proper tail function before flying (covered later in this review)

Note: for best results with the GY192, I recommend you do this GY192 MODIFICATION

I have yet to look at the swash leveling, but the Tail servo looks like it could be recentered. I'll do that another day before I flight test.
Elevator servo wire looks like it is a bit tight on the wire tie work. I loosened one wire tie and gave it a little slack. Wires should not be pulling tight on the servo. That can yeild flight failures.

Included battery is a 2200mAh 3S 15C pack. A velcro strip is pre attached to the battery. A seperate strip was attached to the sticker set, I cleaned the battery tray with alcohol and then placed the velcro strip onto the battery tray and pressed to secure. It comes with female EC3 connector attached. This is the same type that E-Flite and Align use as standard so finding the battery ends (Female) at your Local Hobby shop should be easy.  SOLDERING EC3 Connector.   Female 2pk EC3 at RC Planet

Dynam 40A is more than adequate but be warned that I believe this ESC can start up w/o a throttle shutoff detection. Most ESC's will NOT spin up on power up until you have held the throttle low for a period of time. I started this up once and the throttle hold was switched up and it spun up on me.  So make sure the top right switch on your TX is AWAY from you before powering up the Heli. Make a start up procedure. Write it down and follow it every time. My switch flipped up as I was putting it in the box, then did not notice it.

Rx looks good, I angled one antenna downward and the other straight back
This is a 7 channel 2.4ghz Reciever.
Reciever will already be plugged into the servos but for reference, they are connected as follows:
 CH1: Aileron (Upper Rear Servo driving the rear left swash ball
 CH2: Elevator (Front swash servo)
 CH3: Throttle (To ESC)
 CH4: Tail (To Gyro) (Tail servo then connects to Gyro)
 CH5: Gear (Not connected)
 AUX1: Pitch (Lower Rear Servo driving the rear right swash ball)
 AUX2: Servo Gain channel (Single wire to Gyro)

The Signal wire side of the servo connections is the PIN closest to the Label (top). The GND pin is the side farthest from the label (back). Most Servo cables come in 2 color types: Futaba style and JR style.
Futaba is Black(GND)/Red(POWER)/White(SIGNAL).
JR stle is Brown(GND)/Red(POWER)/Orange(Signal)

Note: On the Rx, there is an EXTENT dial. This dial affects the travel limits of the CCPM servos (Aileron,Pitch, Elevator). The default is 50% (in the middle. If you wish to check this, move it fully CCW, note the position, then fully CW, note the position, then move it half way. This dial is the SAME function as the V2 dial while setting the EXP dip switch. More CW is more cyclic range, more CCW is less cyclic range.

E-Razor 2.4Ghz Proper Tx Setup procedure
TX Dip Switch Photo
Do This setup BEFORE YOU POWER UP Helicopter
Proper Dip switch settings for eRazor (starting left to right)

Verify the V1,V2 knobs are installed correctly, They should rotate from 7 oclock minimum (fully CCW) over and around to 5 oclock max (fully CW)

My recommended Initial setup of the right 3 dip switches:
The right 3 dip switches are used to program certain settings. Normally, all 3 are UP(off), pushing them down, alllows the Tx to record the V1/V2 knob positions for certain settings.  

Here is how you program in my recommended initial settings:
Power on the Tx and wait until the lights stop flashing.

EXP : Set V1(right knob) to 3 oclock, Set V2(left knob) to 10 oclock
        Move Dip switch EXP down, pause, then back UP

PLT/PIT : Set V1(right knob) to 10 oclock, set V2(left knob) to 12 oclock
        Move Dip switch PLT/PIT down, pause, then back up

RUD MIX/GYRO SENS : Set V2(left knob) knob to fully CCW (7 oclock), Set V1(right knob) knob to 2 oclock
        Move Dip switch RUD MIX/GYRO SENS down, pause, then back up.

Power up procedure:
The Rx binds with the Tx on every power up. The Tx pauses for a short while (about 12 seconds) on start up to send out the bind command.  If you don't connect power correctly, the gyro will not initialize. You MUST plug in the Helicopter battery during this 12 second window. If you plug in the Rx too soon (or before you plug in the Tx), the gyro may time out and not initialize even though the Rx has bound properly. The Gyro MUST come on a solid BLUE to indicate it has initialized.
Note: Although the Tx and Rx initialize MUCH like a Walkera 2.4Ghz system, they are not compatible. I tested this with a Walkera 2801 Tx. Walkera has 4, 6 and 8 channel Rx's and the Dynam is a 7 Ch.

1) Verify the Gear switch (top left) and 3D (Idle up) switch (top right) are switched down (away from you). DANGER, VERY IMPORTANT!
2) Verify the collective/throttle stick is all the way down (towards you) and trim tab is in the middle
3) Power up Tx first and count to 5
4) Power up the Heli and then don't touch it (gyro while flashing red is stabilizing.)
5) If gyro sucessfully initializes, it turns solid blue, if not it will flash red/blue. IF so, quickly unplug/plug heli back in. If that fails,then start over again
6) The Throttle will not power up until you pull then push the top left "gear" switch on the Tx. this is a NEW safety feature.  On the old TX, the Throttle would not initialize if the Gear switch is turned up. So start with the switch away from you, then after the Rx is bound and the gyro is responding, Pull then push that Gear switch and the throttle is now Armed.

View Video of Power up (OLD TX)
New Video from Xheli on How to Power up the Helicopter.

Setting Gyro gain in a test flight:

When powering up the helicopter as above, 3D switch should be away from you before turning on!.
It is best to get an experianced pilot to test fly and trim the helicopter for you.

Perform a pinch test :
Gyro Bench/Pinch test
With the helicopter initialized, set V2 fully CCW, Set V1 to 2 oclock.

Hover the helicopter and verify the tail does not wag in a hover. If it does, then land and adjust V1 CCW (do not pass 1 oclock)
If it does not wag, turn it a little CW
Hover again.
Keep doing this until you get a little wag in hover, then turn knob about 10-20 degrees CCW.
Note: On my E-Razor, it was wagging at about 4 oclock. I set it to 3 oclock and sharp 90 degree piros were pretty tight and snappy.
If your tail is not holding well on take off, move it up slowly each time.

Once you get the final gyro gain setting, flip dip switch RUDMIX/GYRO SENSE UP.

Explanation of dip switches:
PIT : Reverses PITCH Servo (CH 6)  On the E-Razor this is the bottom REAR servo that drives the rear right swash ball.
CCPM/ ELEV : This reverses the direction of the elevator movement of the swash. This is like reversing polarity of the SWASH AFR or SWASH MIX for the Elevator channel on most other Tx's
NOR/CCPM : Switches between Normal (UP) or CCPM-120degree (DOWN) swash.
RUDD : Reverses the rudder channel
THRO : Reverses the Throttle channel
AILE : Reverses the Aile servo
ELE : Reverses the ELEV Servo

Normally in the UP position. When moving this down, then back up, it reads the value of V2 and V1 knob (when you move it back up).
V1 knob adjusts the throttle cuve. Default it to 12 oclock, moving it CW will give more throttle near center stick and moving it CCW will give it LESS throttle at center stick.
V2 knob adjusts the cyclic roll rate. 12 oclock yeilds +/- 7 degrees of cyclic pitch range, Fully CW yeilds +/- 9 cyclic pitch range, 9 oclock yeilds +/-  5 degrees pitch range.  5 oclock will yeild a gentle roll rate. 3 oclock will yeild a very agile and less stable roll rate.
Set V2, V1 knobs to the cyclic range and throttle range, then flip EXP switch back up to lock in.
Normally in the up position, V1 adjusts Minimum Pitch in Normal flight mode. V2 adjusts MAX/MIN pitch range in 3D/Idle up mode.
V2 is like the CH6/PITCH setting value in SWASH MIX or SWASH AFR for other Transmitters.  More CW on V2 will give a larger Pitch range min and max.  more CCW will yeild very little pitch range (and make it UNFLYABLE).  
Sample values of V2 and results : 9 oclock = +/-5 degrees, 12 oclock = +/- 10 degrees, 3 oclock = +/- 12 degrees
V1 adjusts the minimum (low) pitch value in normal mode.
Sample values of V1 and results : 9 oclock = -6, 10=-4,11=-3, 12 =-2, 1=0, 2=+1, 3=+2.
Once you have the dials where you want, flip PLT/PIT switch back up.

Normally in the UP position, V1 sets the gyro gain, V2 sets Rudder mix (Revo Mix). Rudder mix is only for Rate mode gyros and you want this off, so V2 should be set fully CCW to turn it off, and Fully CW yields MORE revo mix. If you have a HH gyro and you have rudder mix on, what will happen is as you increase or decrease collective,the tail will spin one way or the other never allowing it to hold.
V1 dial = Gain
12 oclock is 0 gain
CW up to 5 oclock is HH. More CW, more HH gain.
CCW down to 7 oclock is Rate mode. More CCW, more Rate gain.
I recommend 2 oclock for initial flights.
Once you have the gain and rudder mix where you want, flip the
RUDD MIX/GYRO SENSE dip switch back up to lock it in.