That X7 looks like its got some good RJX servos, by Schneckenburger. I have those RJX servos on my Hirobo Freya and I am satisfied with them.

 

I put RJX HV servos in X7 with mixed feelings because in the past I was flying a lot on them. Unfortunatelly two of them burned in flight causing two crashes of 700 helis.

They have very good specs. They are fast, strong, smoother than KST servos. Anyway I trust KST servos more.

Probably RJX are much more sensitive for binding. They can survive binding but later can fry for no apparent reason.

I do not wanna say they are bad. Maybe I had just bad luck.

When I look at both helis X7 canopy looks nicer than canopy on Gartt. Matter of taste. Keep in mind you can put nice canopy on Assault/Gartt too:

It requires some additional effort because you need to modify canopy mounts. This is green fusuno canopy.

There are many threads comparing Gaui X7 with T-Rex 700, Goblin, 7HV, Forza.

I was convinced there are no big differences in flight characteristics. Some pilots flying both confirm this. Some say X7 is better than T-Rex. I will check myself. I am very curious.

Price difference is huge between Gartt 800 airframe and Gaui X7 Formula kit. I really hope X7 is much better in flight.

It should be also very reliable. In general my bigger helis are much more reliable than smaller.

Gartt had some issues in the past but served me well for over a year and a half and 5here are solutions to those issues.

I crashed 800 only once and 700 once due to my mistakes. 800 survived few emergency autorotations. I like 800 size. X7 is 700 size and I am not going to stretch it.


This photo is strong.

Maiden update:

Good news: it is flying (no surprise), I did not crash (surprise)

Bad news: I have two problems. First I noticed in the air. YEP 120A was cutting power all the time so I did not perform any 3D. Second I noticed on the ground. RJX HV servo went mad.

I am surprised because motor and ESC were flying earlier in 800. Servo was also flying earlier in 700.

True maiden is postponed. X7 will have KST servos and I will try YEP with power booster probably.

I am not happy I am patient and can wait. Nothing wrong with Gaui frame but bad luck.

Kbar has realtime Voltage sensor. I checked logs also. Voltage on avionics did not drop below 7V.

Update:
After replacement of "mad" servo with another RJX HV servo motor is working OK, not cutting off anymore. One rotten egg can destoy best cake.

Now all servos pass stress tests...

More tests before maiden for sure. They do not get hot. Maybe I will keep RJX servos in X7. Tough decission. Servo failures are lottery. Even best servos can fail.

 

I maidened X7F finally. I like it a lot already after eight lazy soft 3D flights.

Bahaves like Gartt 700. Does not require very high RPM.

Tic-tocs are much easier probably due to better balance of weight front-rear.

It is more locked and precise but Gartt after year and a half is not as tight fit as it was brand new.

My conclusion... If you are new in 700 class definitely take Gartt 700 with Align upgrades (airframe is 1/4 X7 price at least). After you advance X7 Formula is good option if you want to become second Dunkan or Tareq. For a newbie it is waste of ammo.

I put 180A HV ESC in X5 It is definitely overkill. Main reason was piece of mind and bergain $148 price of RotorStar (rebranded YEP). It is huge so I had to dismount motor radiator on one side.



I could put it in another place but I wanted to avoid making extension of ESC cable to receiver.

 

X7F crashed.

After investigation most probable cause of crash was broken plastc servo horn. After landing boom strike caused some damage.

I lost:
- RJX main blades
- tail boom
- CF tail push rod
- one CF boom support
- TT is slightly bent, probably usable

Lesson learned... never use plastic horns in 700 heli.

To confirm cause of crash I analysed Kbar log.

I do bame myself because I have many alu horns. Plastic horns provided with kit seemed very beefy. Probably previous owner crashed a heli and one horn was seriously weakened.

Frame, electronics, canopy, landing gear survived.

Main shaft and feathering shaft are straight.

It could cause total rekit...

I used throttle hold before crash landing.

 

If you use good plastic servo horns it's not an issue. I punish mine no problem. Have you crashed with them before and kept using them perhaps?

 

That's a bummer @utrinque.

I don't necessarily agree that you shouldn't use plastic horns on a 700 as there are plenty of pilots out there who smack their 700's within an inch of their lives using plastic horns, but I would caution that it is always wise to replace such items after purchasing a second hand machine if you don't fully know it's history. I think the same goes for ball links as well.

 

haha beat me to it @MickyD!

 

Nice Writeup utrinque.... The X7 is a very nice Heli.. Very direct, stable and smooth as you probably have already found out...

There is a very good reason why you don't see many X7's selling 2nd hand... no-one want's to let them go

 

Previous user used pelenty of threadlock. Just to remove tail I ordered two screwdrivers from Taiwan.

I like those:


Before I attempt to touch screws I will heat them with strong soldering iron.

I still have two 800s and two 700s ready to fly.

We learn often hard way. Thank you all for kind words.

I will repair X7F as soon as I have parts. Probably on Monday. I will borrow screwdriver . I will also get parts for X5.

I am still more impressed with X5 performance than X7. Yesterday wind was very strong and X5 gyro needs some tuning. Agility 200 at bar clone etc.

 

Geez thats a pretty ordinary looking servo horn dude!

It's difficult to know for sure, but that crack looks like post crash damage rather than the cause of the crash however the fact that it is a cut down horn makes me sceptical. My guess is that the damage was caused in a previous crash and @utrinque's uber hard smack flying was the last straw that caused it to fail in flight.

IMO cut down servo horns on a 700 are probably only something I would use if I broke one at the field and needed a spare in a hurry. It always pays to check over a second hand heli with a fine tooth comb before you fly it thats for sure.

 

My friend created X7F build thread with photos.

This is what you get in the brand new kit:

There are plastic horns.

More photos here:
http://www.heli-team.pl/forum/viewtopic.php?t=4393&p=57713

For comparison with Assault 700 DFC you get aluminium servo horns. They did not break in 800 crash. One was slightly bent TGY 815 (KST 815 BLS) servos survived 800 crash:


Many said: "you get what you pay for"

Now I will pay for new 700 mm blades.

 

It's a fair point you raise that the aluminium horns are likely to be stronger than the plastic ones, but that's not necessarily a good thing some of the time. Yes you get rigidity in an aluminium horn and they don't flex too much when you're beating on them, but there are other ways to skin a cat that give you rigid control and a failure point during a heavy dirt nap.
The problem I see with solid aluminium horns like the ones shown above is that there is no significant failure point in them unlike plastic horns. That means that when you have a crash where load is transferred back through the servo, plastic horns would be likely to strip on the spline, aluminium horns on the other hand don't strip and don't tend to bend too much, transferring all of that force back through the drive train and end up stripping gears instead.

In the end it all comes down to personal preference I guess. I personally love the Synergy method where you have a CF horn that screws onto the small round servo horn with four bolts. That give super crisp response and a failure point in a crash. I have never stripped any servo gears on a Synergy, only the splines on the plastic horn.

What horns does Duncan and Tareq use on their X7's? Stock plastic ones?

 

Dunkan is using metal servo horns and KingKong III ESC in 2015:

He romoved motor radiator?
Gaui X7 with Tail Boom Cover
SpinBlades 3blades prototype
Scorpion 4525 520kv
ESC Hifei 200a
Rc Proplus
Mks X8 Bossion Brother Edition
Optipower 5800 6s Bossion Edition
Beast X Plus HD

Source:
http://www.helifreak.com/showpost.php?p=6343774&postcount=1

Dunkan 2014 X7 setup for Helimasters was:
Motor Hk 4525 520kv
ESC Controller Scorpion
Main Servos Mks x8
Tail Servos Mks x8
Flybarless SystemBeastx
Mainblades SpinBlades 685mm
Tailblades SpinBlades 105mm
Accu Optipower
Radio System Futaba 18mz

Source:
http://www.heli-masters.com/pilots/dunkan-bossion/

 

What is this?

http://helidaily.com/tech-tip-handling-your-gaui-x7-one-way-bearing/
http://helidaily.com/how-to-modify-one-way-bearing-in-the-gaui-x7/

I never had to disassemble OWB in Gartt clone! It works flawless since January 2014.