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Nov 26, 2007, 07:22 PM
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Discussion

T-Rex 450s Aluminum kit


Hi all,

I've been using my Esky Lama V3 for more than a month and to tell the truth, I'm starting to get frustrated. I crashed a few times, but now I control it correctly and I would like to do more. I tried it outside a few times, but as soon as there is a light wind, it's like playing with fire. It crashed once because the blades clashed (front wind).

Anyway, I was wondering if I should go bigger, but 1500$ is a bit more money that I would like to invest now.

So, before I look for a Raptor 50 or a T-Rex 600N with a good receiver/transmitter/gyro/etc, I thought I could spend 500$ and see if I'm *really* into it.

I found the following package on eBay and it looks interesting:

# T-REX 450S Aluminum Helicopter Set(User need to assemble it)
# New Align 430X Brushless motor(3550KV)
# RCM-BL35X 35A Brushless ESC(Govener Mode)
# Ailgn 11.1V 2100mAh 20C Battery
# Telebee Dual Rate Mini Gyro RCE-500X
# 325 Carbon Rotor Blade
# Futaba 6EXH Transmitter
# Esky Receiver
# 11.1V battery charger
# 4x Tower Pro 9g Servos

From what I understood, it seems to contain all I would need to make it fly. Maybe I would need one or two extra batteries and another charger (my Esky charger can charge 11.1V batteries).

I also understand I do not get the best quality in electronics (whatever the receiver/gyro is). And the transmitter is only 6 channels, so that may not be suitable for a bigger heli if I ever want to upgrade.

I'm ok with that. It's a kit for 415$ (free shipping), so I could at least try it out. If I really want to upgrade some parts, I'll always be able to do so.

Is there something in that kit that is a real no-go? Please base your comments on my situation: beginner who flown a V3 Lama for a few months but would like to try a bigger one, with a 500$ budget.

Thanks!
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Nov 26, 2007, 08:03 PM
Sippin' on Kool Aid
well, all in all, it is a way to get you going with a t-rex kit. but there are a few things i would be wary of:

that esky RX would probably not be so great in a t-rex and i would reccommend a definite upgrade to something more quality like a berg 7.

the gyro is ok to start off but i would, again, upgrade to something more quality that you'll get more use out of as you progress and get better. go with either the GY401 or the Logictech 2100T and definetly get a quality digital tail servo like the futaba 9650.

also, dump those tower pro servos ASAP and grab yourself some hitec hs-65's they'll last you so much longer and give you better response.

aside from that, you should be pretty ok with what you got there
Nov 26, 2007, 08:30 PM
Registered User
Thread OP
Ok, so that's what I thought: electronics are cheap, but the heli is not so bad.

But what is the difference between good servos/receivers and bad ones? It takes more time (milliseconds?) to react, it worns out faster (months? day? years?)? Don't forget I will not do loops and such in the next months (but I may get tempted within a year...).

Upgrading all the electronic parts would certainly cost 300-500$ more.
Nov 26, 2007, 08:45 PM
Registered User
The basic differences are:

Cheap servos fail, many of the really cheap ones will fail without warning and in flight. The result is a certain crash. As a beginner, you want servos that will never, ever fail without warning and will probably survive a crash (although they may well need replacement gears, a gearset is cheap).

Tail servos need to be capable of reliably holding the tail, and of handling the (rather extreme) workload.

Gyros... well, a good gyro holds the tail where you put it, a cheap one will have ideas of its own. It's always better if you can rely on the gyro... you don't get nasty surprises then. Unfortunately, the gyro can be the most expensive single component in the heli.

Receivers... cheap ones don't handle the vibration of a heli, don't handle the electrical interference from being too close to the ESC and motor (there's not room in the airframe to move them further apart) and so on. Glitching is a curse.

Cheap ESCs don't necessarily have a governor worth using, and sometimes the BECs are rated optimistically, which means if you load them up with thirsty servos, they brown out and cause radio problems.

So, on that list of bits, the gyro, RX and servos are junk, but the rest of it looks basically OK. Those batteries are quite likely to fail pretty quickly, but they perform OK while they last.

So, you will eventually end up getting a Futaba 401 or Logictech 2100 gyro, but in the mean time a Futaba 240 or CSM 200 would do. Hitec HS65s are basically the standard servos, but BlueBird 306BBs do OK too. On the tail servo, Hitec HS-45 or HS-81 would do, or you could go digital. MKS P-03 digital servos are great and not expensive, but they use so much power you will have to get an external BEC or upgrade the ESC, and they require programming since they come out of the box programmed for micro truck steering servos.

As for receivers, I fly Spektrum so I don't really know, but I'd expect the Berg 7 to be good as it is so often recommended.
Nov 27, 2007, 12:18 AM
Sippin' on Kool Aid
Quote:
Originally Posted by cron
Ok, so that's what I thought: electronics are cheap, but the heli is not so bad.

But what is the difference between good servos/receivers and bad ones? It takes more time (milliseconds?) to react, it worns out faster (months? day? years?)? Don't forget I will not do loops and such in the next months (but I may get tempted within a year...).

Upgrading all the electronic parts would certainly cost 300-500$ more.

yes, it will cost more initially but using the cheap stuff with end up costing you more in the end because you have to replace all the parts you broke. it will also cost you time, beucase the time you end up spending on rebuilding could have be spent on flying and learning.

its better off to get the good stuff right out of the gate. then you just dont have to worry. plus, you have the support of us guys here on RCG who usually run most of the good stuff and can help you out

P.S. 1000 Posts!! YEE HAW!!
Nov 27, 2007, 05:10 AM
Certified
jgoodwin's Avatar
Exactly what those guys said. i bought a package a lot like the one you are looking at. The only electronics I have not replaced on it are the Motor and ESC (but they are probably next). I even went DX7 because of glitching.

I have a friend who is starting out and he is going to build the 'best' from the ground up. He has already bought a good charger and a DX7 with an AR7000 RX and he has not even bought the T-Rex kit yet!

You might spend $100-200 more, but buy the kit with just ESC and motor and then buy the best stuff: hs65mgs, good gyro, good (or great) tail servo, DX7 and RX. You will not regret it. Ask around, there are plenty of people how wish they were in your shoes so they could do it again right from teh start and actually save money buy spending a little more up front.

If you are still not sure about the hobby and don't want to 'buy good and buy once', then buy an E-Sky RTF or an RC-Tek 'rex' copy.

-J
Nov 27, 2007, 05:32 AM
Team Mulikow
Gino CP's Avatar
Or get a CopterX 450 AE from www.ehirobo.com. Stay away from the combo kit. The Elf servos and gyro are no good. Stay away from the BatteryHobby lipos too. The 3E 11.1v 2200mah 20C lipos are good. The Futaba radio and receiver is ok. The CopterX 430L motor and 30 amp esc are ok.

For budget electronics, you can get:

Hitec HS-65HB x 3 for cyclic
Hitec HS-56HB for tail
Rc-Tek 730 HH gyro or the Asian counterpart the Gulang GM730
(Cheaper still, you can get a Telebee. Not as solid, but enough for general flights)

Alternatively, you can look for the Phoenix 450 in the US. These are distributed by RC-Tek. Basically a TRex 450 SE V1.
Nov 27, 2007, 09:30 AM
Registered User
Thread OP
Interesting options. Ok, I'll put that on paper and I'll see where I can go.

Thanks!
Nov 27, 2007, 02:14 PM
Sippin' on Kool Aid
Yea, i totally forgot about that CopterX. check that out!

great little heli from what i've been reading. and a lot of the parts are supposedly compatible with t-rex parts or visa versa, so if you have a LHS that carries t-rex parts you'll have fairly easy access to them

just make sure you take some time and search around. there are great deals going up everyday. you should have busted in on some of those amazing thanksgiving deals at hobby lobby and gotten yourself a dragonus!
Nov 28, 2007, 11:43 AM
Registered User
Thread OP
Thanks for all your comments.

I came up with the following (I'll definitely have to push the budget a little bit more in the 800-900$ range):

- Gyro: Futaba GY401 (about 125$)
- Tail servo: Futaba 9650 (about 55$)
- Servos (3): Hitec HS-65HB (about 25$, so 75$)
- Transmitter: Futaba 6EX (about 180$)
- Receiver: (included with the transmitter)
- Motor: Align Brushless 430XL (about 56$)
- ESC: Align Brushless ESC 35A with BEC (about 60$)

For the motor and ESC, they're sometimes included with the frame (if I buy a T-Rex), although they seem to be different (motor is often the 430L and ESC the 35X). Don't know the difference.

So, this is about 550$ (almost all the budget I was considering to spend). Now, I can have a look at frames.

- T-Rex 450S Kit Combo (about 200$ with motor/ESC), for a total of 634$
- T-Rex 450S CF Kit Combo (about 260$ with motor/ESC), for a total of 694$
- T-Rex 450SA ARF Combo (about 270$ with motor/ESC), for a total of 704$
- T-Rex Carbon Frame Matrix Combo which comes with everything I wanted for 735$
- CopterX 450AE (about 200$ with extra pricy shipping...), for a total of 750$

Wow... That makes a lot of choices in the same price range. If I read correctly, the 450S and SA have aluminum and plastics parts (the CF version has Carbon Fiber and plastics) and the CopterX has all aluminum parts. Am I right?

Then, would the CopterX be the choice to make? Would all the parts I listed above fit in that frame? Am I missing any parts? Which batteries/charger should I consider buying?

Thanks again for helping me to choose.
Nov 28, 2007, 12:58 PM
Registered User
blade strike's Avatar
call rc-tek... see what they can do for you on a diablo/skyshark. He has some pretty nice servo's and gyro. I have heard him giving killer deals out and it is xmas time

to learn more about the heli's go here:
http://www.rct450.com/
Nov 28, 2007, 02:14 PM
Sippin' on Kool Aid
Quote:
Originally Posted by cron
Thanks for all your comments.

Wow... That makes a lot of choices in the same price range. If I read correctly, the 450S and SA have aluminum and plastics parts (the CF version has Carbon Fiber and plastics) and the CopterX has all aluminum parts. Am I right?

Then, would the CopterX be the choice to make? Would all the parts I listed above fit in that frame? Am I missing any parts? Which batteries/charger should I consider buying?

Thanks again for helping me to choose.
The 450S comes with either aluminum of CF side frames. The SA comes with aluminum. The t-rex's (SCF and aluminum and SA) come with plastic head/tail parts. I think the CopterX comes with aluminum.
Nov 29, 2007, 07:05 PM
Registered User
Thread OP
Asked a few quotes around and now to the final questions:

- if I have a gyro than can do digital, a digital tail servo and three non-digital servos, will I be able to use the "digital" feature of the gyro/tail?!?

It may sound a silly question, but I never assembled a kit before...

- in an electric heli, is there only one battery?
Nov 29, 2007, 07:46 PM
Registered User
Each servo only cares about its own drive signal, so it doesn't matter if one servo is getting high-rate digital updates from the gyro... the others will get what they need from the RX.

Usually there's only one battery, and a circuit called a BEC supplies power for the low-voltage parts. The BEC can be integrated into the speed controller, or a separate item. Sometimes electric models will use a separate receiver battery, but none of the usual reasons for doing that apply to electric helis.
Nov 29, 2007, 07:49 PM
Registered User
cron:
Yes, you can use "non-digital" servos for cyclic control and still use the digital setting on the gyro and your "digital" tail servo.

Most electric helis (especially the smaller ones) use only one battery and use a BEC (battery eliminator circuitry) to power the receiver and servos from the main flight battery. The BEC can be integrated into the ESC (electronic speed control) or it can be a separate device. Some helis use a separate battery pack to power the receiver and servos. The BEC got its name by virtue of its use eliminating the need for the separate receiver/servo battery.


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