FAQ, Before you purchase, Upgrades & Normal Issues - Summarized

[Boddan]

OK…

I thought to try and summarize everything I have read here on the forum when I have been trying to figure out what to purchase. These are the questions I have been asking my self and what I have picked up as the FAQ and normal/necessary upgrades and issues. If you feel I've missed something or written something incorrect please feel free to write so here or PM me. I thought this would fit well in the sticky's but you decide Mr. Finless

Of course everybody have to look at Mr. Finless videos about the T-Rex 500 build and any other videos he has made also (soldering, ccpm, ball links, etc.). They are really great sources of information and you learn a lot.

But this is more pre-purchase and post build…
Hope this helps!

//Boddan

P.S. This is a work in progress... D.S.


Cyclic Servos
What servos to buy? This is a frequent question here and heavily debated with a lot of different opinions, I will try to summarize them here.

Hitech 5245MG (approx 45$/p)
This is a very good "bang for the buck" servo. They have high torque, good speed, metal gears and is all in all a very popular choice. This servo will serve You well if you are not doing the most extreme 3D flying. One down side of the 5245MG is that in a crash the gears will not break since they are metal but sometimes the housing (servo case) might crack. There is however replacements for this too. I have also heard that Hitech have revised the cases and they should no longer crack. Also these servos come with blue aluminum servo arms.

Futaba 9650 (Approx 60$/p)
These nylon gear servos are very much recommend here. They are very fast and have high torque. Most people want to upgrade these to metal gears (available HERE). The wires on these servos are a bit short and you will need a wire extension per servo (depending on Rx location of course). The 9650's are good as tail servo for beginners as well.

Futaba 9257 (Approx 60$/p)
Popular choice also as tail servo as it has high speed but perhaps not as much torque. So it will be good to start out with but you might want to get higher torque later on.


JR 3517MG (Approx 90$/p)
The more expensive servo. For extreme 3D'ers and also for people with high budgets and do not want to upgrade down the road.


Gyro and tail servo combos
The gyro question is very much a personal preference. Again I will try to summarize some of the characteristics and comments of the different gyros.

Futaba GY401 (approx 150$)
The Futaba GY401 gyro is one of the more popular choices. Many upgrade from their 450 sized helis and bring this gyro along with them. They are fairly easy to setup and hold the tail very well. Some pilots never need to upgrade from this gyro ever. One of the negatives with the GY401 is that it will not keep a constant piro rate.

Servos usually combined with the GY410 is:
Futaba 9257 - A great servo used by many here on the forum. It will get you far into sport flying and 3D but eventually you will want to upgrade to a faster servo.
Futaba 9254 – This is the faster/stronger servo. Larger size than the 9257 so you will need to purchase the T-Rex 600 tail servo mount to fit it to the 500. Some people will modify their 500 servo mount to fit the servo but most find it easier to purchase one instead. The 9254 is a quite heavy servo compared to smaller sized which of course will have an effect on center of gravity (CG)
JR S3500G – This gyro works great with the T500, most likely you will never have to upgrade from this.

JR G770 3D (approx 160$)
The G770 gyro is growing in popularity. It is a constant rate gyro* which gives it an advantage over the GY401. It is almost in the same price as the GY401 and most guys here on helifreak will tell you it is as good or better than the GY401. It supposed to be more difficult to setup but well that's done it should be a great gyro.

* making the piros more constant since it is sensing also the tail movement when giving rudder input, a rate gyro will be sort of "bypassed" when pilot is giving rudder input

Servos usually combined with the JR G770 3D is:
Futaba 9257 - A great servo used by many here on the forum. It will get you far into sport flying and 3D but eventually you will want to upgrade to a faster servo.
JR S3500G – This gyro works great with the T500, most likely you will never have to upgrade from this.
JR S8900G – This servo is faster and stronger than the 3500G but also bigger, heavier and more expensive. It will fit the 500 (probably with the T-Rex 600 servo mount) but most say the 3500G is good enough on this bird.

Spartan DS760
This Gyro is programmable with most all modern tail servos
Most say this is the best gyro ever. High price and high demand makes them hard to come by though. Servos I'm not sure about but I believe the JR S8900G is a popular choice. A great feature with the Spartan is CPU connectivity you can plug it in to you Computer and set direct parameters!


Batteries and pinions
Most people use 6s lipo battery packs with about 2200-3300mah. With this setup I believe most people use 13 tooth pinion (included in kit) but you can also run a 12 tooth pinion to reduce head speed and increase battery time. Normal flight (basic hover and some forward flight) gives you approximately 6-8 minutes of flight dependant of your pack.

Two sets of 3s battery packs can also be paired together to give a 6s pack. This configuration works great to start out with and if you already have packs from your old 450 sized heli but if you are to buy new 6s works better, is lighter and easier to maintain. If you are to run 2x 3s make sure they have about the same cycles and are of the same Mah and quality.

Some use 5s lipo packs as well, usually with a bit more amps than an 6s, perhaps 3300mah and up. To make up for the lower voltage a bigger pinion is needed, I believe many are running 15-16 tooth pinions.

Some known and good battery brands are:
- Kong Power
- Flight Power
- Outrage
- Thunder Power
- Zippy (cheapest by far)

Align Battery packs have been known to not having very high quality. With that said they are not bad! Just many have experienced that they are not holding up as well as many others when it comes to longevity and performance after many cycles. They are sold at a very attractive price though.

Examples of battery pack characteristics: (by gregor)
2500mah 25c - Excellent stock replacement.
3000mah 25c - Heavier than stock, but not a noticable change in CG. (runtime anyone know?)
3300mah 25c - About the heaviest and largest pack that will work. Does alter CG and may require both battery tray mods and canopy mounting post mod to fit correctly. (runtime anyone know?)

Chargers
Chargers are chapter all of it's own. If you go with one of the well known chargers you will win in the long run. Less known can easily get too hot and you might want to upgrade in the future. You will want to get a combined charger/balancer to as little on your work bench as possible and keep the charging procedure simple.

When buying a charger You will most likely have to purchase or make your own power supply, if you do not want to charge of a car battery. A good power supply should have at least 10A but future proofing choose one that could handle something like 15-20A, cost around 80$. You can make one out of an ATX computer supply for just a few bucks. There are great posts here and on the web on this topic.

Thunder Power TP610C or TP1010C
Well known brand and very good chargers. The TP610C will do the job just fine at around 139$ and the TP1010C will do the job great and is also good for future needs, it will cost around 200$.

Hyperion EOS 0610i Duo
A very popular choice and can charge two 6s batteries at the same time! This comes at a higer cost of course, approximately 270$.

Bantam E-Station BC6-Duo and Bantam E-Station BC6-10
The BC6-Duo includes the power supply and for a good price, approx 170$. This charger will charge at "only" 5A so it will fit your T-Rex 500 needs just fine but for future (more powerful) helicopters it might not have the power and you will want to upgrade. The BC6-10 does not have an built in PS but will charge at 10A.

FMA Cellpro 10s (by gregor)
Charge up to two 5s packs at a time, 1 pack 10s or fewer cells up, max output 260watts. The charger automatically determines the pack size and optimum charge current. Constantly reads each cell's internal resistance and adjusts the charge current to safe and optimal levels. Charges through the packs node connector as well as through the discharge lead. Balance charge is up to 1amp vs most other mfg which use current bleeding method limited to 300ma.

Transmitter & Receiver (Tx/Rx)
You will need a computer Tx to be able to program you heli. These days the 2.4ghz Tx's are the most popular choice by far. They have close to no interference and "glitches" compared to the 35mhz/72mhz Tx's which could sometimes mean glitches mid air. Although the T-Rex 500 have some issues with static building up in the tail boom and creates such high "noise" and "arches" that it will interfere also with the 2.4ghz. There are ways around this though, see section below.

Here are some examples of radios and receivers. If you can, I would recommend going to a LHS or local flight club and ask if you can look at them in real life, feel them in your hand and check out the menus.

Spektrum DX7 / DX6i w. Ar7000 / Ar6200
The DX7 is one of the most popular choices when it comes to Tx's. They have great range, quality, feel, menus, price, etc. Users say it is super easy to setup and will suit your future needs very well. The DX7 will work with both AR7000 and AR 6200. When you purchase the DX7 it comes with servos, servos you unfortunately not can use in an T-Rex 500. They will due fine in a plank (rc airplane). You can sell these on the after market or you can try and find a retailer who will sell you the Tx/Rx without the servos (will be approximately about 279$, I did this with helihobby.com).

The DX6i will due great for your T-Rex 500 needs and have most of the programming features that you will ever need. It has "only" 10 model memories compared to the 20 of the DX7. The DX6i also has a reputation of having a bit of a "plastic" feel to it and will not take you into nitro helis, for this you will need the 7'th channel. You could also need the 7'th channel for larger electric helis or if you want to go scale and have retractable landing gears. However at 179$ it is a great Tx/Rx combo which will serve your 500 well. The Dx6i will work with the AR7000 if you buy a new one. It seems older DX6i's would not work with this rx. (DX6i/AR7000 info from Ozz58)

Comment from Spektrum them selves on the question: What is the difference between DX6i and DX7:
The DX6i and the DX7 have the same programming. The DX7 has a smoother gimble movement. You will not loose anything if you purchase the DX6I other than 1 extra channel

Futaba 7C 2.4g / 6EX 2.4g
The Futaba and Spektrum radios are very similar when it comes to features. Prices are 220$ and 350$ for 6 channel and 7 channel. Some say the like the feel of the spectrum better, higher quality feel, but on the other hand the static issue seems to be more of an spectrum issue than an Futaba issue. The 6EX futaba have a smaller display than the 7c, but both have smaller displays than the DX7

JR Radios
I have not read much about these and can really not comment on them. I know that JR owns Spectrum and heard that spectrum produces JR's 2.4ghz modules.

JR X9303 2.4 (by snjbird)
Has all the futures of the DX7 plus a larger model memory and a larger LCD display, and higher resolution, of coarse it has 9 channels, it has a similar body to the DX7 with a more solid feel, it is a true mid range radio, by that I mean price wise not reception. The 9303 has been around in the FM and PCM model for quit some time, its menus are very intuitive, and its roller data entry system is super smooth way to move through the well thought out menus. it is compatible with all Spetrum Brand Aircraft Receivers. This item does not include servos or a receiver battery pack. Cost $629.00

Tail Bobbing up and down
So Your head is bobbing up and down when You spin up your T500?!
Usually this is because the T-Rex 500 loves head speed.

By always being at (or over) 75% throttle at mid stick (normal mode) you will most likely not have this issue. A normal throttle and pitch curve is:

Normal Mode:
TC: 0, 50, 80, 90, 100
PC: 42.5, 46.5, 50, 75, 100

Idle1:
TC: 100, 95, 90, 95, 100
PC: 0, 25, 50, 75, 100

Static issue
As mentioned above the T-Rex 500 heli is prone to get static build up which can disturb your 2.4ghz receiver and cause a lock out. The GF frame many will tell you that it is not vulnerable to this issue, but people on this forum have had issues even with this frame (e.g. nikolai). There is a great thread in the sticky's about this so I will just touch upon this subject briefly. These mods and tricks will most likely get rid of the issue:

Bearing connectivity
Make sure to have connectivity between the tail shaft bearing and the front belt pulley shaft bearing. Do this by adding a cable that will have contact with the front bearing and run it to the boom (where You sand the color of the boom where it is inserted into the boom block) then do the same at the rear bearing to the rear of the boom. This will ensure connectivity between the bearings and reduce static.

Silicon spray
To spray or soak the belt with silicone spray will make the belt to lead electricity. This trick is the only "mod" many are using but I believe the most common and fail safe is to do this and to do the bearing connectivity mod.

Frame grounding
Some people ground the frame to the black cable of the battery/esc. There are many opinions about this weather it is necessary or not but I have not read that much about this so I'm sure you will find more about this in the static sticky.

Torque Tube (TT)
This is a replacement for the belt all together. It is a shaft running down the boom with gears at either ends instead of the belt. This upgrade will cost around 80$ and will defiantly get rid of the static issue. Beginners who will touch ground with the tail blades are advised to stay clear of this until they can control the heli a bit more. When crashing the TT can be a bit more expensive due to stripped gears and bent shaft but all in all it should be a great upgrade.

Sticky thread by fireup: https://www.helifreak.com/showthread.php?t=61205
Static thread by ChasHeliCop, incl vids: https://www.helifreak.com/showthread.php?t=81808


Upgrades
Metail tail unit
To get rid of slop in the tail you can buy the metal tail unit and also the metal pitch slider. This will make the tail more controllable and as an added bonus it will reduce the static issue since the closed tail box disappears and by that not allowing static to build up as fast.


Metal Mixing arms
The T-Rex 500 is almost full aluminum and carbon fiber but the mixing arms in the head are palstic. These can over time become sloppy and reduce your overall performance. By replacing them with the metal ones you will be free from wear and also they will be much more crash resilient. But as many of the folks here would say: in a crash something has to give!


RdLohrs gyro/rx mount and battery/ESC mount
The issue is that there is static in the boom block and most do not want to mount electronics there. And the stock tray that goes in the back if the frame is very "flimsy", this will affect the gyro since it needs a stable platform. RdLohr makes a Plexiglas mount to replace the stock one. It is super stable and you can easily mount your gyro on top and your rx on the bottom using velcro. This way you will easilly be able to remove the bottom plate to service.

He also makes a battery tray replacement. This will allow for your Velcro or double sided tape to stick perfectly both top and bottom, for your battery and your esc.

[firefly412]

Nice work!

[jeffros1805]

great write up! I trolled the T500 forum for weeks before deciding and buying mine. This ^^^ pretty much sums it all up into one FAQ.

needs to be a sticky.

[Ozz58]

One thing you might mention, if you have a newer DX6i radio, it will work with the AR7000 receiver. That's what I have on mine.

[Pod Jockey]

Excellent work Boddan
Wish this thread was around 3 months ago, I spent about 5 months researching all about the T500 while saving for it. the only thing i went tight ass on was hitec HS225mg on cyclic, im only learning, they centre perfect and at this stage cant fault them.

[BennyTRD]

Nice work Boddan.

Originally Posted by Ozz58

One thing you might mention, if you have a newer DX6i radio, it will work with the AR7000 receiver. That's what I have on mine.

How do you tell if you have the new one? Mines a few months old. New enough?

[Gregor99]

EDIT: Cleaning up post. Removing content that has been added to the first post.

Boddan,

Thanks for the great work. I'm putting together my T500 shopping list this so this topic is very timely.

Here are couple other things that I plan on looking into. Details were missing would be appreciated.

Motor Comparison
Compare run time, motor durability and intended applicaiton (3d or sport)

Align 500L Brushless Motor(1600KV) RCM-BL500L
Scorpion HK-3026 1210KV
Scorpion HK-3026-1600KV
Scorpion HK-3026 1900KV (for use with 5S packs)


Blades
Align 425 Carbon Fiber Blades H50069
Align 425F Carbon Fiber Blades
Align 425D Carbon Fiber Blades
RCP II Carbon Fiber Main Blades 425mm
HDX 425mm FRP Blades


BECs
The RCE-BL60G (stock Align ESC) includes a 3a (5a burst) switching BEC. When using an ESC with linear BEC, or a ESC that doesn't have BEC, an outboard BEC is required for 6s systems. Adding an outboad BEC can reduce the ESC's operating tempature as well as reduce the potential for brownouts.


SportBec 3.5a - Output is selectable between 5V/6V using a small slide switch.
http://www.helidirect.com/product_in...oducts_id=4550

HobbyWing C-UBEC 5A for 3-10 Lipos
http://www.helidirect.com/product_in...oducts_id=5210

Medusa Potencia 3.5A/5V or 6V BEC
http://www.helidirect.com/product_in...oducts_id=1387

Castle Creations 10amp. Output voltage from 4.8 to 9 using the Castle Link. If you have one already, great. Otherwise its not good option unless you are wanting to invest in the CC line. There have been some reports of the CC BEC failing on 6s and higher setups. Usally the failure results in an overvoltage condition that damages the electronics attached to the BEC. Dispite that, many have had good success with it.
http://www.readyheli.com/Castle_Crea...p/csem0005.htm

[ncnguyen123]

very nice work! wish i saw this before buying mine. finless should definitely make it a sticky.

[nickolai]

it was mentioned that there were no static issues with the gf frame, that is false, i had disconnect issues with the gf and i believe others have as well. the torque tube, however, does solve the problem.

[HeliSmith]

Boddan nice write up!

Edit:
Here's my setup tips it will be growing too if I ever find the time. lol

Installing a ground wire:
http://www.helismith.com/500grndwire.htm
Wire braiding 101:
http://www.helismith.com/wirebraiding.htm
Trimming Futaba servo for JR plug:
http://www.helismith.com/futaba_trim.htm
Tip to install front two servos:
http://www.helismith.com/500servo.htm
Making your own step down regulator:
http://www.helismith.com/9257_step_down.htm

[Boddan]

Thanx for the nice words guys!

I have made some modifications to the thread, much thanx to the comments and PM's i have gotten. (updated: static issue GF, Tx's, chargers, batts, mods, static links)

If you would like to add more please help out by writing up short summaries of what you want to add. I do not know much about upgrades and other stuff than what is up there, as a matter a fact I have never even seen a T-Rex 500 or even a transmitter that is not the E-Sky Belt CP one.

I would like to add som low end servos and battery times up there, can anyone help out?

[Boddan]

And also, I was told I need to proof read it. Since I am Swedish and english is only my second language please feel free to PM me about type-o's and similar.

//Boddan

[Laurens]

I think this FAQ is good enough to be made sticky! Nice work Boddan.

[snjbird]

Congats Boddan!

[Boddan]

WOHOOO! Sticky status!

I would like to thank my family, my boss (who does not know I'm doing this on job time), etc

No really, I just summarized your thaugts!

//Boddan

[Boddan]

Thanx to snjbird for your input!

Now updated again...

[DLBT]

Nice work Boddan. I've been lurking in this forum for some time in preparation for placing an order for a T500. Just didn't know what to order. When order time comes this will really make it easier to decide.

[Boddan]

"We aim to please"

[JAG1]

Hey man,this is good,I LIKE!!!

[belkington]

Excellent Work Boddan.

I have been searching for answers to all of the questions you list now they are all available in one place - well done my friend.

Just need to save a few more pennies and bag myself a hot T-Rex 500 set up.

Thanks again

Ben