Official GAUI NX4 Build Thread

[Matt Nasca]

Hey everyone, I wanted to make this build thread to help others planning for the NX4 and/or building the NX4 to have a resource for information regarding the build.

The build is extremely straight forward and the easiest build I've ever done. It shouldn't take more than several hours. I got the airframe together in 2 hours (that includes taking the pictures). I'll be doing the electronics as a supplement to this because I don't have electronics for the NX4 I'm building. I'm going to take pictures of another NX4 that's built and show the wiring.

I'd like to underscore how easy this build is! GAUI built the entire head and most of the tail sections so that was a nice surprise. A couple of small details left me scratching my head but overall, a pure joy!



As expected, the parts came in organized boxes.


Everything is neatly placed in bags. This is where my only real gripe is. I found myself searching bags for a few parts. Not a huge deal because there aren't a lot of parts, but by the time I was half way through the build, I had a lot of open bags spilling parts.


In true GAUI fashion, they have you build one half, then add the other. I like doing it this way, it seems much easier to me.




Make sure you get these in the correct orientation! I know a really good pilot who got the bottom bracket upside down and the bearing came out in flight! Make sure that the bottom bearing faces down and the top faces up!




I really wish the countersunk screws were countersunk better. It doesn't have any effect on anything whatsoever but it's worth mentioning to GAUI for future kits




This guy goes together quick!


Occasionally I had to refer to my trusty ruler for screw measurements. GAUI uses screws that are plenty long for good grip!






Continuing on with the half frame


In the boom clamp (which is upside down in this pic) you can see the screw sticking out slightly, that is there to pin the boom. It presses into the boom and should work very well.




**NOTICE** I put this on backwards, even though I read the directions! lol, it actually goes on the outside of the frame! I didn't catch it until I went to setup the pushrod.




THIS is the correct way!


I like the reinforcement caps GAUI includes for key screws. Plus they look cool!!


Frame built!


This is the cutest little clutch. It's about 50% of the size of a .90 clutch. The liner comes installed.


The gap was set perfect out of the box


I added red threadlock to certain parts I didn't want to vibrate loose, like the set screws on the starter coupling.


The fan assembly mounted to the little OS 37. Another NOTE: Remember my complaint about on bags? Well there is a little slip of paper with a diagram on adding a washer on top of the fan assembly before the nut that locks it down on the crank shaft. I did not initially notice this so I didn't install it. Only after I got done and had spare parts did I figure it out.


Standard looking clutch and assembly


I put the motor mounts on first, it seems easier to install that way. You can use a long allen wrench to secure them vs a angled one later.








Before I get comments about the skids being on backwards.... It's in the manual that way




I took my little pin screws out of the boom supports and CAd them in place. Also CA, the screw in. If you do not, they WILL vibrate out in flight. Thankfully a canopy clip fits the hole perfectly and will work in a pinch.


This was all uneventful. There is a slot in the main shaft that the set screws fit into to secure it. I LOVE this because you don't have to muscle the screws (and risk striping them) down to keep the shaft from slipping.




Here is how the tail comes! Yes GAUI uses locktite and they tighten stuff down very tight. I'll call it "GAUI tight" from now on.


The tail is essentially the same as what is on the X4 & X5 so really nice!! You want to use the outside holes on the tail output shaft.


As you can see they did use threadlock


This has to be the easiest tail to build. There are two set screws in the hub and two link screws and you're done!! I found the tail to be completely smooth even without oil. I put some Tri-Flow on it for good measure.


The head also comes completely pre-built!


The swash does too.


Some had threadlock and some didn't so check them!




The pitch arms had threadlock




When installing the links remember GAUI out!


These little guys have a rubber pad that gets inserted to keep the tank from foaming. They are fun to install


Pluming the fuel line is pretty easy.






SImply screw in the rails and viola!




When you install the muffler pressure port, don't overtighten it. I broke it off and had to extract it. Luckily I had another which I secured with JB Weld.






I put the header tank on with double sided tape and zip ties. The included solution would work but if you want to use that method, you may choose to modify it slightly. For me the zip ties work great.


This little tab helps hold the canopy on. I chose to epoxy it on versus installing it with the included double sided tape. I got the idea from Andy P. Thanks man!


I an using a Mini VBar with Pro. I don't show a picture of this but there is a metal plate that comes with the kit to add mass to the VBar. I used it and in my opinion it is needed with the Minn VBar. I chose to use Futaba 30x30mm pads instead of the 3M tape that is included.






I really like the canopy on the NX4

[GasNerd]

Awesome post! Wish I had it a week ago, but I am going to save this one for my Second NX4 that is sitting on the shelf in the box

The hardest part for me was the tail setup. I initially setup the arms that connect to the tail grips too tight and my slider was binding.
I had a tough time getting the resolution correct on my tail servo. I also ended up stripping two sets of torque tube gears before I got the mesh correct.
Everything else was smooth even with this being the first nitro that I setup.

I got up in the air today and it is an awesome machine - even in a basic stable during the break-in felt very stable.

-GN

[Glenn Goodlett]

It took me two hours just to clean the oil off the screws. I don't think it matters but it looks like you have one of the servo mounts on up side down.

Also I like to hear your opinion as to using the rubber grommets to mount the servos or not. Mounting the gov sensor needs some discussion too. I would like to machine a plate to mount the Align sensor but haven't had the time.

[BlazinBones]

Thank you, Thank you, Thank you.. Mine is sitting in the box for lack of motivation but I think you have just awaken my senses. Great Job

Subscribing.....................

[vteknical]

Mine is 80% complete. Nice kit, pain in the arse playing the screw and hardware game. No rhyme or reason to the mixed up bag madness. M3x6 no M3x7 Other than that, things are going together quite nicely.

[willlig756]

im just waiting for servos to arrive. I cant wait to fly this heli..

[Rotors Up]

Fricken Awesome Matt, Great job. My kit just came today and I'm very impressed with everything.

Would it be advised to take apart the factory assembled parts and check for loctite and proper grease? My only gripe is the tail boom being pre-built It's hard to say if the torque tube bearing was loctited to the torque tube shaft. I would have liked to build this assemble myself. I will however, pull apart the head and tail assembly and grease all the thrust bearings and spindle. Also the auto rotation hub is pre-built and should be taken apart cleaned well and greased. Other than the above mentioned I see no other issues with the kit or quality of the parts. Very nice kit from Gaui!

Thanks again Matt

[Matt Nasca]

Thanks guys! I hope this post helps and can be used for a repository of good build info. I'll be adding more later as I have time.

As far as the things that GAUI prebuilt, like the head and tail, they are GAUI tight and smooth as butter. I left mine as is but if you feel better opening it up and checking, by all means do it. It certainly won't hurt. The swash was the only place I found a single ball without threadlock.

[caralmar]

Originally Posted by Matt Nasca

Thanks guys! I hope this post helps and can be used for a repository of good build info. I'll be adding more later as I have time.

As far as the things that GAUI prebuilt, like the head and tail, they are GAUI tight and smooth as butter. I left mine as is but if you feel better opening it up and checking, by all means do it. It certainly won't hurt. The swash was the only place I found a single ball without threadlock.

My swash was all threadlocked, but I'm glad I checked anyway. I did take the head apart to check the feathering after my crash and found grease in there, so I'm sure the thrust bearings are greased...however, its not easy to be sure. Unlike Align helis, the thrust bearings are sandwiched between two radial bearings, so you have to take the radial out before you can examine the thrust bearing. Since I don't have any extra bearings, I didn't want to risk damaging them by taking them out, so I left them alone...figure once parts come in, I'll order stuff and then I'll feel more comfortable wrenching on it.

EDIT: Oh, and thanks Matt for the nice build post!

[joallen001]

Great tip on putting motor mounts on first. Makes it much easier.

[willchua]

Wow! that's good intro! Great job Matt. One thing that would need your kind advise. Realised you are using Mini-Vbar, wondering what gorvenor are you using. I'm using the same but i can't see any possibility to set-up the gorvenor for nitro/engine. FYI, i have updated the mixer with latest version. Or, where can i get more detail info pertaining to the set-up. Many thanks in advance.

[Matt Nasca]

I'm using the GAUI governor. The Mini VBar governor is not capable of use with Nitro at this time. If you want to use the VBar gov then it must be with full size. I'm probably going to do this at some point in the future. For now, you could use the Throttle Jockey, Align governor, GAUI governor or maybe even a multi gov.

If you are using the GAUI Governor or the Align Governor with the Mini VBar AND you're using satellite recivers, you'll need to do this file modification to enable to use of RX A, as the signal input.

http://hf.rob.com/showpost.php?p=4423244&postcount=1

If you're using an external receiver, then this above modification is not necessary.

**This is an at your own risk modification!** That being said, it worked well for me with no issues at all.

[ranma103]

I'm using the skookum gov on mine and found it to be quite good using the align sensor not sure on the msh or icon units.

Sent From My Galaxy S3 Using Tapa Talk 2.0

[WillJames]

Nice thread Matt. Thank you. I went ahead and stuck it.

[Matt Nasca]

Originally Posted by WillJames

Nice thread Matt. Thank you. I went ahead and stuck it.

Thanks Will!!

[RonFly]

My NX4 is in the mail. Looking at online manual.... Do I need a crankshaft clamp for my OS 37sz? Do I need a clamp to tighten the nut as shown on page 6. Thanks

[RonFly]

My new Gaui NX4 is in the mail. Will I need a crankshaft clamp to tighten the fan nut shown on page six of the downloaded manual? Thanks

[Matt Nasca]

Originally Posted by RonFly

My new Gaui NX4 is in the mail. Will I need a crankshaft clamp to tighten the fan nut shown on page six of the downloaded manual? Thanks

I usually take off the bottom plate and place the folded corner of a clean thick towel inbetween the rod and wall. It seems to work pretty well and doesn't damage anything. I'm sure this is NOT the right way to do it!! I've done this on 5 nitro motors and haven't ever had an issue.

YMMV

[dksia]

Great thread, Matt.

I went to change out the black head dampers for the red ones.

Someone really needs to get the people at Gaui to lose the bottle of red loctite that's used on the spindle bolts. I destroyed one of my allen wrenches trying to remove the bolts. Second try, second set of harder wrenches, got one of the bolts loose. I've tried everything short of a torch to get the second bolt loose once I got the spindle out but the second bolt is in there for the life of the shaft.

Blue loctite and some appropriate application of torque would be sufficient to keep these bolts in place.

[Matt Nasca]

Originally Posted by dksia

Great thread, Matt.

I went to change out the black head dampers for the red ones.

Someone really needs to get the people at Gaui to lose the bottle of red loctite that's used on the spindle bolts. I destroyed one of my allen wrenches trying to remove the bolts. Second try, second set of harder wrenches, got one of the bolts loose. I've tried everything short of a torch to get the second bolt loose once I got the spindle out but the second bolt is in there for the life of the shaft.

Blue loctite and some appropriate application of torque would be sufficient to keep these bolts in place.

Thank you.

lol...I'll pass that on to GAUI but I have a hunch they do it for safety. I've only been able to get one loose myself and unless I'm replacing the entire feathering shaft, I just remove the one and re-tighten it with blue. If I need to get both bolts out that means the shaft is toast and I don't mind putting the giant vice grip in the middle and breaking the other screw loose that way.

I think Bobby may have a Grippy that fits the NX4 as another option.