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Dmitry

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Xtreme 90 build
02/28/09 at 04:13:10

Some time ago I have received RJX Xtreme 90 kit from BFCarbon. There are several variations of X90 kit. X90 kit comes with torque tube or belt driven tail. As well there are 3 types of frames: G10, Silver CF and Black CF. So, there are 6 variations to choose from.
I got kit with TT and Black CF frames.

Overall kit looks very good. There are only few plastic parts; mostly it is carbon fiber and metal. All gears are made from Delrin. Gears are very strong, smooth and do not wear out as fast as plastic gears. I am in the middle of the build right now, and I want share some build photos with you.

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Dmitry Active Poster ___________________ Online Edmheli.ca Posts: 110	Re: Xtreme 90 build Reply #1 - 02/28/09 at 04:46:19 First I have built components which are required to assemble main frames. Swash controls and tail arm: Clutch bell: Clutch bell has special holes to mount governor magnets. Bearing block has two big bearings to support the bell. In addition there is second support bearing block (see next picture).
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Dmitry Active Poster ___________________ Online Edmheli.ca Posts: 110	Re: Xtreme 90 build Reply #2 - 02/28/09 at 04:47:36 3 main shaft block and one addition block to support clutch bell.
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Dmitry Active Poster ___________________ Online Edmheli.ca Posts: 110	Re: Xtreme 90 build Reply #3 - 02/28/09 at 04:49:33 TT gear box. The kit has few different washers, which are required to align the gears. It requires some time, but end result is awesome: zero play and super smooth gear box. As I said early, gears are made from Delrin.
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Dmitry Active Poster ___________________ Online Edmheli.ca Posts: 110	Re: Xtreme 90 build Reply #4 - 02/28/09 at 04:53:12 Main frame: Main frame structure is extremely rigid. And looks great, not as wide/fat as some other helicopters .
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Dmitry

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Re: Xtreme 90 build
Reply #5 - 02/28/09 at 04:58:23

Main frame with electronics:

I have used following electronics:
1) Ar7000
2) MultiGov Pro (This governor has lots of advanced features. And setup procedure is very easy using special LCD screen )
3) SolidG with Futaba 9256 (I like how this combo works on mine two X50)
4) 3x JR 8915 (know as 8717 in NA ) for cyclic
5) Futaba 9254 for throttle
6) ReactorX for power regulation

Soon I’ll post more pictures. Thanks for watching/reading.

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« Last Edit: 03/05/09 at 09:35:25 by -eSmith. »

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-eSmith. EdmHeli.ca Administrator Offline buy, fly, crash, cry, repeat. Posts: 2218 Edmonton, Alberta, Canada.	Re: Xtreme 90 build Reply #6 - 03/05/09 at 09:40:34 Off topic replies have been moved to this thread.
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Dmitry

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Re: Xtreme 90 build
Reply #7 - 03/20/09 at 11:53:22

Drive gear assembly.

The kit includes 2 sets of main gears: T90 for OS91/YS91SR and T93 for YS91ST. So, no need to buy other main gear if you want to change gear ratio. Main gear is helical, and works quite and smooth (I have experience with these gears on mine X50). Gears are made from Delrin. They are very strong and do not wear out as fast as plastic gears. For one way bearing I am using “3 in 1 oil”. Mine one way bearings were locking with other lubricants. But with this oil even stock Trex600 one way bearings (lots of people have problems with them) works great.

Here is the picture with installed drive gear assembly and swashplate.

I flew mine X50 pretty hard last year and have found that swashplate does not develop lots of play as some other popular helicopters. I think X90 swashplate should work great too.

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Dmitry

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Re: Xtreme 90 build
Reply #8 - 03/20/09 at 12:14:08

Engine and fuel tank installation.

I choose OS91HZ for my X90. I did not want to buy engine with pump, because very often they are not working properly. The simpler - the better

. Cooling fan sits very tight on the crank. I was heating the fan with hair dryer to put it on the crank. After installation it is impossible to dial in the fan. But the good thing is that fan run out was just a little bit over 0.001’’.

As you can see, the fan is made from metal. Considering fan design the fan should be very efficient.

X90 (and X50 too) comes with header tank and it has special mounting place for it.

Here is the heli with installed fuel tanks and engine.

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Dmitry Active Poster ___________________ Online Edmheli.ca Posts: 110	Re: Xtreme 90 build Reply #9 - 03/20/09 at 12:16:13 Here is one more picture which shows engine and fuel tank installation.
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Dmitry

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Re: Xtreme 90 build
Reply #10 - 03/23/09 at 15:11:24

Now one of my favorite parts - Tail Case.

Tail case made from one solid piece of metal. Tail case gears made from Delrin, as all other gears in the kit. Special washers should be used on shafts to align gears in the tail case.

Tail rotor grips made from hard plastic. First versions of X90 had metal grips, but these grips had vibration issues on certain RPMs. New plastic grips do not have that problem. Each grip has two radial bearings, one trust bearing and rubber damper.

Tail case assembly feels very smooth and precise.

Tail case installed on the heli:

Manufacture recommends using 95mm tail blades if head speed is higher than 1900 RPMs.

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Dmitry

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Re: Xtreme 90 build
Reply #11 - 03/25/09 at 12:00:20

The main rotor head.

The rotor head has lots of adjustments. It is possible to make it very stable or very responsive/aggressive. On my X90 I am using the most responsive settings with negative delta. The head comes with hard dampers and it is very stiff. So, no need to changed dampers if you are in hard 3D. From my experience with X50 I can say that RJX heads does not develop additional slop fast. I have used X50 for quite some time and the head is still like new. RJX heads feels very precise in air. Overall RJX heads looks like some shiny medical tools

.

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Dmitry Active Poster ___________________ Online Edmheli.ca Posts: 110	Re: Xtreme 90 build Reply #12 - 03/25/09 at 12:09:29 The muffler. I have installed Hatori #939 (SB-20FH) muffler. It is specially designed for OS91HZ engines. It looks big and shiny.
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Dmitry Active Poster ___________________ Online Edmheli.ca Posts: 110	Re: Xtreme 90 build Reply #13 - 03/25/09 at 12:37:54 Now some pictures of fully completed X90.
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Re: Xtreme 90 build
Reply #14 - 03/25/09 at 12:39:52

I have tried to cover briefly X90 build. I hope you like my thread.

RJX heli is very nice choice. I like the responsiveness of RJX helis. The head is very precise and does not develop slop fast as some other popular helicopters. RJX works hard to improve their products. They have improved many components of X50 and X90 already and every new release of X50 and X90 just becoming better and better.

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