500 Building the Gaui NX4

[Tony]

The Align fuel line is 5mm OD and 2.5mm ID. Looks like the stock line was 2mm ID.

As for that feathering shaft, I wouldn't install that in any of my helicopters after being heated that hot. By heating it to where the metal blued, it decreased the strength of the steel. Wouldn't want the blades to come flying off because of a broke feathering shaft. The likelihood is low, but it's still there.

 

[stokke]

The Align fuel line is 5mm OD and 2.5mm ID. Looks like the stock line was 2mm ID.

As for that feathering shaft, I wouldn't install that in any of my helicopters after being heated that hot. By heating it to where the metal blued, it decreased the strength of the steel. Wouldn't want the blades to come flying off because of a broke feathering shaft. The likelihood is low, but it's still there.

I'll order a new feathering shaft. I'll use this one until the new one arrives. Thanks Tony.

 

[coolgabsi]

Marius, if making an order, order yourself a Grippy.. Its a a one way bearing installed on an extended shaft, gives you leverage. If I didnt have that, I would have had to heat my screws like this too on my 700.. I use blue, and that holds it that tight.

Tarot has one.. fits 6mm-8mm-10mm feathering shafts so fits 450 -700 size..

there is a RED NECK GRIPPY .. that has a 9mm hole too.. I use it for my WHiplash .. with 9mm shaft.

 

[Westy]

I got one of these Feathering Shaft Wrench for RC Helicopter

Here is my Buddy Code for ou to get a discount for 14 days
Feathering Shaft Wrench for RC Helicopter


It features one way bearings in 4mm, 6mm, 8mm and 10mm which will hold your feathering shaft in place so you can unscrew the bolt from the end of the shaft.

 

[stokke]

I got one of these Feathering Shaft Wrench for RC Helicopter

Here is my Buddy Code for ou to get a discount for 14 days
Feathering Shaft Wrench for RC Helicopter


It features one way bearings in 4mm, 6mm, 8mm and 10mm which will hold your feathering shaft in place so you can unscrew the bolt from the end of the shaft.

That's pretty clever, I gotta get myself one of those! Thanks Westy

_

I'm currently having a hard time getting the DS515M servos to come to life. Trying to troubleshoot it now.

 

[Westy]

No Worries - I lke hte ergonomic design ... to fit in your mit! natural tendancy to fist grip it ... gives you plenty of power to undo the toughest of blade grip screw!

I actuallly looked at getting all the different sizes and machining holes on a nice piece of alloy, but it was too expensive! just simpler and cheaper to get one of those! ... or for that price .... 2 of them in case you lose one! haha

What FBL controller are you using and having trouble with? do you have a servo tester to give them a quick run through?

 

[stokke]

What FBL controller are you using and having trouble with? do you have a servo tester to give them a quick run through?

I found the reason, I'll write about it further down. Thanks

_

I thought I'd look a bit at the electronics as the servo install is coming up.

This is the button for the glow igniter. Disassembled it because it would not fit in the designated hole when assembled.

Here's where it'll be mounted. But I think I'm gonna wait with the wiring until I know more about what part are going to go on.

The glow igniter does come with a standard servo connector to get power from the Rx. As you can see on the pic below, the signal wire goes nowhere. So I think I'll cut off the servo connector and run the glow igniter outside the BEC's power supply, straight from the 2S Rx pack.

I got the Hobbywing 3A BEC. It will supply 5V or 6V from a 2S Rx pack. The BEC's output (5V or 6V) is controlled by moving a jumper. I was told that this BEC might be to small to deliver enough juice to the Rx and servos - what do you guys think?

Hooked up the two cyclic servos I have (the last one is on it's way), to figure out which servo horns fit the best. But my AR8000 Rx did not send signal to the servos! Turns out the AR8000 will not function with servos until I hook up a Satellite - which I don't have.

The reason for me using the old AR800 Rx, is that the Ikon is coming in the same order as the last servo.

So I had to give up the servo setup for now, and thought I would assemble the links to their correct lengths.

Noooooo! Broke one of the link heads for the throttle linkage.

The reason I broke it, is because the rod is too long.

As you can see the rod is 65mm on the pic, but that link on the end is threaded all the way in already! I'll wait with this link until I'm gonna fit it to my throttle - then I'll cut the link with my Dremel to the correct length.

Installing the muffler.

Those metal lock thingys go on the bolt right?

I did not use any thread lock on any of the stuff threaded into the muffler - this is correct, right?

Gasket. The instructions are not very detailed when it comes to mounting the muffler, but I think I got everything where it's supposed to go.

Muffler finished

I really hope the last parts shows up tomorrow! The Sat's and governor come from England (off eBay) - but that's been in the post for over a week now. I have high hopes for flying this thing this weekend...

 

[Westy]

nice.... The Star washers go on the muffler bolts and yep no need for TL on those ... however I would use some Hi Temp thread sealer like locktite 357 (I think I was that one I have used extensively in the Automotive trade.

Re the UBEC .... 3A is pushing it on that really as FBL servos do a lot more work and you may be running it on peak quite a lot, If you are just doing a bit of sport flying .... no worries ... dependant on your hard core 3 d style! Mwah Mwah! - Kidding!

Can you get a 5Amp one to be safe?

So What was the Servo issue?

 

[pvolcko]

I have no nitro experience, but... is the inside gasket hole supposed to be so much smaller than the engine's exhaust port? Does it match the port on the muffler? I would think that particles of the gasket would fray off and possibly get into the motor or otherwise restrict flow.

 

[callsign4223]

That's an exhaust gasket. Any fibers would be blown out into the muffler. That being said, it does look like it could do with some cleaning up.

 

[Tony]

As stated, the star lock washer will go on the bolt and rest against the head. and you are also correct in not using any thread locker on those bolts. With heat (other than red threadlocker), it will actually turn into a lubricant and not lock it.

I would get rid of that gasket. Just take it off. Put a VERY small amount of Permatex Black silicone on the muffler where it rests against the block. I mean a very little amount. Smear it on, then dab it with yoru finger. Wipe off your finger. Dab it some more. Do this until you cna see aluminum through the silicone. When it's very thin, bolt it on.

Yes, there is a reason for this. The gasket will crush under the pressure of the bolts causing the bolts to come loose thus rendering yoru lock washers useless. The bolts will back out and you will have the same thing happen that happened to me. By bolting it directly to the block with ONLY silicone, it's a metal to metal seal that will not crush. And the very little silicone that you put on there will fill any small holes that may be in there.

 

[Westy]

if anything did go in ... it would burn up on entry!

 

[pvolcko]

It's a 2 cycle engine, right? Means that exhaust is not always one way like on a 4 stroke. That's why they have tuned pipes for 2 strokes. The exhaust system is designed to help cause some of the fuel-air mix that makes it's way into the exhaust to rebound back into the combustion chamber before the piston closes off the exhaust port.

 

[Westy]

exhaust is always out.... the only differences (apart from it firing on every upstroke and the fuel mixture) is the scavenging effect that allows the fresh air into the chamber to scavenge out any left over exhaust gasses .... thne as the piston travels up the cylinder the exhaust port is sealed and the inlet still open and draws in as much air as possible until the piston covers that pot and then compression begins and since hte glow is on all the time .... as soon as the mixture ratio gets to flash point, the engine fires and the piston is forced down again.

Nitro is one of the crudest forms of compression ignition as there is no timing advancement system or CDI unit to get better performance out of it. - that is why they burn through so much fuel as most of it is unburnt and released into the atmosphere.... in the form of white/grey smoke.

Hope that sheds a little light onto the topic

 

[stokke]

So What was the Servo issue?

As I wrote, the AR8000 would not fire up the servos unless I hooked up at Sat. And I do not have a Sat

I would get rid of that gasket. Just take it off. Put a VERY small amount of Permatex Black silicone on the muffler where it rests against the block. I mean a very little amount. Smear it on, then dab it with yoru finger. Wipe off your finger. Dab it some more. Do this until you cna see aluminum through the silicone. When it's very thin, bolt it on.

I will keep the gasket in place until I get hold of some silicone stuffy. Thanks

__

Regarding the BEC, which looks to be a bit under powered: I found this. It does not say what output voltage is produced - can I assume it's 6V output then?

Thanks for all your comments!

 

[Tony]

If you keep the gasket, then you need to open up that port quite a bit. Bolt it down, then take it off and cut out the part that is on the inside of the crush marks. Otherwise you will experience reduced performance from the engine.

 

[stokke]

Just talked to a guy in the local club. He's sort of a guru (built over a 100 helicopters I heard LOL), and he's got the NX4. He cut out his own gasket from a beer can LOL

 

[Westy]

we call those folk ... bush mechanics!

- - - Updated - - -

This is what I would ti if it were me.....
get hte manifold bolts and screw them onto the gasket.... then get a small ball pein hammer and tap round the head inside port area .... this will give you the profile you need to cut out!

 

[stokke]

The misses just texted me that the Sat's and gov have arrived! Now I only need the FBL unit, and will be picked up on my way home from work (hopefully) Woohoo

 

[stokke]

I got my sats and gov sensor, but sadly my last order did not show Hopefully I'll have it Monday.

After all the feedback on the exhaust gasket I thought I'd take it out and make a custom one. Now, the reason the stock gasket was not "good" was because it covered up the exhaust outlet on the motor. But when I removed the muffler and looked at the stock gasket again, I noticed that even though it's smaller than the motor outlet - it's a perfect fit over the muffler inlet! So I'm keeping it on there.

At least now I got a sat to hook up to the AR8000 so I can center up my servos

Instructions want 18mm spacing for the ball on the servo arm, but I can have 17 or 19 on the Align arms - so I went with 17.

Per the instructions I mounted the ball on the inside of the arm, but that just didn't look right.

Also, two out of four bolt securing the servos had to be cut down due to them being too long.

Got out the Dremel and shortened four bolts.

To get the servo geometry right I had to get creative with the balls. (LOL)

Hmmm...

Servo arm stopping on the servo casing - not good.

Cracked a link. These Gaui links are brittle and of poor quality - I'll swap them out for Align links and balls later on I think.

More tinkering with spacers and positioning to get the geometry right.

Nope.

Tried out some Align balls I had lying around. But they were too small for the Gaui links - and got sloppy.

With Align ball.

Moved the ball on the outside. This is what I ended up with - geometry good and straight.

I got myself a larger BEC. This one will do 8A Should do the job I think.

Comes with led indication on battery capacity. Fancy.

Started with the link for the rudder. The manual states the rod is 255mm, and that the rod WITH links is 245.5mm. LOL what?

Rudder servo mounting.

So Gaui obviously suck at getting the lengths right in the instructions - but they also suck at cutting the rod to the correct length.

That rod is barely long enough to reach the rudder horn.

Had to figure out the geometry here as well.

The rod was just long enough to get the links threaded on good, so it's gonna work - and it's gonna be safe.

Installing the push glow.

Button.

Connecting to glow plug.

Mounting the BEC. I couldn't find a better spot, but it works and the canopy fits.

Throttle servo.

Throttle servo and BEC switch mounted.

Throttle servo rod too long. I'm glad I own a Dremel...

The ball mounting for the throttle arm stopped against the motor.

Grinded down the head of the bolt that hit the motor.

After a bit of swapping and fiddling I got it to work with proper geometry.

Oh yeah, on full throttle the link binds against the arm. To fix it I'll just grind it down 1 mm or so.

Boom.

Never seen this design before - I like it

Tail.

Never seen this design before either. Nuts instead of bolts for the tail feathering shaft.

You have two positions for the tail hub. All the way out, or a bit inwards.

I choose the "a bit inwards" position, as I experienced some binding when the slider reached the end of the shaft.

What? These bolt look a bit long.

When I tighten the above mentioned bolt I get some serious binding. I'll try to figure out this tomorrow.

All the balls, links, rods and servo related stuff sucks on this model - not impressed. The overall quality looks good though, but there will definitely be modifications to this model.