View Full Version : T-rex 600 Setup Help....

01-18-2008, 07:14 PM
well, couldnt wait any longer to buy the T-REX 600 :tc:

stayed up all night last night putting this beast together "WOW" im impressed with the quality out of the box I bought the carbon fiber model with the 600XL brushless motor.

im new to this electric side of r/c ive always been a nitro guy, but i have a few questions with the electric setup......

so many radios to choose from? ive almost got my mind set on the DX7 but also like the futaba 7ch.... anyone have any thoughts?

also im palnning on using the JRG7703D & 8900G tail servo and gyro setup
anybody have any complaints on this setup?? never used it before but it seems great ($250 it better be) anything better ??

also what do you .50 size guys/girlz run as far as li-pos
im guessing 22.2v 4000 - 5000 mah 16c ?
i was shocked when i saw prices for the packs $300 :Q:sad:

id like flight time and performance not worried about cost......

also any help on radio setup would be great......

want to get this birdy in the air........;-)

01-19-2008, 01:04 AM
This is a great calculator for helis that I have found. Much more than just headspeed, it calculates all kinds of things, including variables on battery selection, weight, rotor loading and speeds - see for yourself! You can make a lot of decisions regarding your power needs, etc. http://dhrc.rchomepage.com/calc.htm

The GY401/Futaba 9254 seem to be very popular, as well. Visit Finless Bob's Tech Room for set up and how to videos on everything (including your heli) and the gyro/servo combos, etc. http://dhrc.rchomepage.com/calc.htm

Good luck!


01-19-2008, 06:51 AM
thanks for the site.... im glad i found this out before i bought my batterys, i was only going to get about 7 mins of flight time, $16 more a pack and ill gain 4 additional minutes with more mAh

01-19-2008, 09:05 AM

I might add that if you change the pinion count down a notch (sometimes two) you can angle more on duration rather than balls-out 3D power (unless, of course, you want that). It can be the difference between screaming along in 4th gear or dropping it into overdrive, and depending on your weight, etc, can add several more minutes on to your flight plus allow a smaller, lighter and less expensive battery. The calculator is essentially a spreadsheet, and you can try a lot of different combination depending on your flying style and what you want to do.

01-19-2008, 07:21 PM
thanks for all the great info on that calculator...

a couple more questions i have on this electric setup......

Im using the 600xl motor and it came with the RCE-BL75G ESC

also it came with a RCE-B3X external BEC

the instructions on the BEC say that if im using this with a speed contoller that has a bec output i need to remove the red wire of BEC output on the speed controller... where is that wire at?? the servo wire? not sure if this speed controller has a built in BEC (instructions on that dosent say).. why would they include a external BEC if it did right?

also it came with a 5.1 volt regulator for tail servo, but all my servos can handle 6 volts so im sure this isnt needed, ive always used ni-mh baterys for all my nitro choppers. this is all kinda new to me on the electric side of things...
any help is apprecaited......

01-19-2008, 08:04 PM
Go here: http://www.helifreak.com/showthread.php?t=55538

It's a video that explains the differences between ESC's w/BEC's and standalone BEC's and inline regulators. Plus, it explains how to disable the ESC's BEC if you have a separate one and why you want to do this.

Also, I would go for the DX7, especially if you fly guerrilla-style at fields where there is no frequency control. If you keep your eyes open on Ebay you can get a receiver and transmitter, charger, etc, new-in-box for about $220.



02-04-2008, 02:58 AM
I am going to use the DX7 for my Trex 600. The Trex 600 comes with a separate BEC so no wires to disconnect. The Align in-line regulator is to protect the Tail Servo if you use the Futaba GY401 & S9254 servo which is most often reccomended as the best unless you are going for all out 3D. The S9254 does not like higher voltage and the Regulator reduces them to 5.1v or so.

I am using a different BEC which allows me to push 6V to all servos and to the regulator. I will power the Rx and the Bec for the servos with a 7.4v 2150 mah battery to avoid possible glitches shutting down the RX. There is suspicion that the Align BEC & Rx Battery is insufficient and might be allowing the Rx to glitch and causing crashes.

Good Luck EdH:eek:

02-04-2008, 08:14 AM
Pfatz, thanks for the reply.

Just from all the issues that I have read in a number of different boards regarding BEC & power supply issues, I think you have some good points.

I have two 1200 mAh 7.4v lipos that would probably serve the RX-BAT function well, while at the same time giving some extra time on the main batt.

Can you feed 7.4 into an AR7000 and get 6v at the servos? Then an inline regulator (as opposed to 'reducer') to the tail digi servo. Does the GY401 run on the same 5.1v?

Any idea how long you anticipate your battery to serve the three cyclic servos? How does one determine drain of a servo, anyway? The 1200 mAh runs two 370 motors in hover for about ten minutes. Servos can't drain more than that, can they?

02-04-2008, 05:08 PM
Hi Curtis
Your Lipos should work, however Align sends a 1900mah Rx lipo & mine is 2150mah. The higher the mah, the longer you can fly before charging.

The Rx controls the Servos & the ESC.

To wire the bird, you go 7.4V > BEC > Rx > Servos and ESC(powered by the main bat) with the exception of the Rudder ( Gyro/Tail Servo) if you are using the GY 401/S9254 Servo. The S9254 only wants 5.1V or less.

For the Rudder only: Rx(6V) > Regulator (5.1V)> Gyro > Tail Servo (S9254) That is why your in-line Reg.

I can't help much with flight time. I am building my battery pack from A123 cells harvested from the DeWalt 36V Cordless Tool Packs.

All this is info I picked up from the forums and from talking to other folks. Hope it helps

02-04-2008, 05:11 PM
????Sorry hit the button twice

02-04-2008, 09:57 PM
Your flight time with the 600E will depend on how aggressive you fly, among other things. I do not fly 3D at the moment, but a bit of aggressive yanking and banking, and I am getting around 8 minutes from an FP EVO25 5000. I am using a hardened 10T pinion, stock ESC, as well as torque tube tail drive. With 3D I believe they are around 5 minutes.

Also regarding RX issues I have changed to the 6 amp Align BEC and regulator, along with a Spektrum Votage Protector plugged into the RX.


Bob C.