SmackTalk RC Quick Tips #5 - The GAUI NX4

[Gawl]

Great video the crew at Smack Talk RC put together on the NX4, and it's free! Enjoy!

[u8at711]

Thank you for the video. now I under stand the whole motor alignment thing.

also, bobby's skids are slanted forward. hummm,

[joallen001]

Originally Posted by u8at711

Thank you for the video. now I under stand the whole motor alignment thing.

also, bobby's skids are slanted forward. hummm,

Yes I did mine backwards like the manual. I have seen pics of them both ways. Is there a correct way?

[jczankl]

No wrong way on the skids. Personal prefrence.

;-)

[vteknical]

Nice video!!

[tauscnc]

Great video Bobby and fun to watch too.

[dksia]

Bobby mentions a few "mini" servos that should fit the NX4. Among his list are ones from Hitec. I had a $250 gift card to Tower Hobbies (won it at a local club meeting) and decided to give the new Hitec 7245 and 7235 servos a shot in this heli. These servos have some pretty decent specs and are spec'ed to run straight off 7.4 volts to boot, with metal gears. Looked good on paper.

Although these are classified as mini servos, they do not fit the NX4, and don't even come close. The servo is actually way too short (longest dimension -- mounting lug to mounting lug center points) to fit.

With quite a bit of work, the CF frames could be made to accommodate these servos for the tail rotor and throttle -- drilling some new holes in the CF, perhaps slotting the existing ones.

However, for use as swash servos, there is not a reasonable mod to make them work. In this application, the problem with the mounting holes being too close together is only part of the problem. The depth of these servos from the bottom surface of the mounting lugs to the bottom of the servo is too great. Even if the mounting lug dimension could be accommodated, the bottom of the servo runs into the side frames long before the servo gets properly positioned on the angled mounts. Perhaps these two problems could be accommodated with the addition of a CF spacer under the lugs, however, that still leaves the elevator servo as being problematic.

Oh well, I was still able to put these servos to use, upgrading the Hitec 5245MGs in my old reliable Trex 500.

Time to scratch Hitec servos from the list of possible servos for the NX4.

[mode1mike]

I am confused as to using a Futaba BLS 257 for throttle, if you look in the Smack talk video pro tip #8 Bobby uses a BLS 257 for his throttle see time 51:53.
He mentioned this throttle servo in a different part of the video also.

The reason I am posting in this forum is that I copied this exact setup as shown in this video and after many searches can not find anyone recommending this servo for anything other than the rudder.

Since I have already bought 2 BLS257 servos for my NX4 should I use it or?

[Gawl]

Just because you haven't seen someone using it doesn't mean it won't work. The futaba servos are expensive, when your Bobby and get them for free price is not an issue

[jczankl]

When testing the NX4 we used the BLS257 on Everything including Cyclic. They worked great however they are a nylon gear so they would strip easily,

The BLS257 Will work great for throttle and Rudder.

[Matt Nasca]

Originally Posted by mode1mike

I am confused as to using a Futaba BLS 257 for throttle, if you look in the Smack talk video pro tip #8 Bobby uses a BLS 257 for his throttle see time 51:53.
He mentioned this throttle servo in a different part of the video also.

The reason I am posting in this forum is that I copied this exact setup as shown in this video and after many searches can not find anyone recommending this servo for anything other than the rudder.

Since I have already bought 2 BLS257 servos for my NX4 should I use it or?

Hey Mike,

I don't know how many of the Savox servos you bought (after we spoke), but I have the Savox for cyclic and BLS257s on my rudder and throttle and they work great! Or if you already got 4 Savox servos, save one BLS257 for the rudder on your X4 electric (that you'll want after you totally fall in love with the NX4.)

[dksia]

Setting up the NX4 -- what's the overall collective pitch range to shoot for with this heli, and recommended amount of cyclic pitch?

[Matt Nasca]

Originally Posted by dksia

Setting up the NX4 -- what's the overall collective pitch range to shoot for with this heli, and recommended amount of cyclic pitch?

Collective 11-13 deg seems to be good and cyclic is tough to say because with the VBar you have agility settings and it isn't set by degrees of cyclic. I run my agility at 100 and collective at 12.5.

[dksia]

Thanks, I've got a 3GX I'm going to try. It wants to see cyclic, at least for initial setup, at 8 degrees, and collective at about 12.

I was wondering what kind of pitch the OS 37 could handle in the NX4 -- you have answered that question.

Thanks.

[jczankl]

I am running 13 degrees with no problems.

[mode1mike]

Originally Posted by jczankl

When testing the NX4 we used the BLS257 on Everything including Cyclic. They worked great however they are a nylon gear so they would strip easily,

The BLS257 Will work great for throttle and Rudder.

JC--- Thanks for answering my question, I plan on using the BLS257 for both Rudder and Throttle.

[mode1mike]

Originally Posted by Matt Nasca

Hey Mike,

I don't know how many of the Savox servos you bought (after we spoke), but I have the Savox for cyclic and BLS257s on my rudder and throttle and they work great! Or if you already got 4 Savox servos, save one BLS257 for the rudder on your X4 electric (that you'll want after you totally fall in love with the NX4.)

Hi Matt--

Thanks for the answer!!!
As far as the Savox I bought 3 so the 2 BLS257 are claimed by the NX4
The future X4 it will have to get it's own BLS257

[wattybotts]

Hi Dave,

Thank you for your comments about the servos not fitting in the model...

We are currently aware that some of the JR Mini Servos (3717HV) and Hitec (5245MG as you mentioned) do not fit in the NX4. The biggest problem is that all of the servo manufacturers have not standardized the dimensions of a "Mini" servo. Every single manufacturer has decided to go their own way and make their own dimensions both in terms of bolt hole positions, and spline positions. Needless to say, this makes it quite cumbersome for both the manufacturer and the customer.

At the moment, any Futaba, SAVOX, Align, or GAUI "Mini" Servo will fit in the NX4 with no problems. There may be other manufacturers out there who make a servo that are the same as these "most common Mini Servos", but I am not 100% certain. We felt it was important to make the most common mini servos fit with no modifications and with precise and correct geometry.

As for the others, such as the JR and Hitec, we are creating different servo brackets depending on which servo you are looking at. This way if someone wants to use 3717 servos on cyclic for example, all he needs to do is purchase 3 new parts (sold as a package) and he is good to go...

Here is an example of how it will look. Hope to see these parts released shortly...

Cheers!

[dksia]

The Hitec 7245 and 7235 looked promising with their ability to handle 7.4V and their torque/speed specs, and metal gears. The metal arms shipping with them also were promising. But those servos are the same size as the 5245, so too small. I could have made them work for rudder and throttle, but not the cyclics -- bummer. My Trex 500 got the 7245's instead.

The kit overall is really nice and well thought out. There are a few issues with hole tapping and length of some of the screws in the kit, but nothing that a typical modeler can't work around.

[GasNerd]

Originally Posted by dksia

The Hitec 7245 and 7235 looked promising with their ability to handle 7.4V and their torque/speed specs, and metal gears. The metal arms shipping with them also were promising. But those servos are the same size as the 5245, so too small. I could have made them work for rudder and throttle, but not the cyclics -- bummer. My Trex 500 got the 7245's instead.

The kit overall is really nice and well thought out. There are a few issues with hole tapping and length of some of the screws in the kit, but nothing that a typical modeler can't work around.

I am using the Hitec 7235's for cyclic and the 7245 for throttle w/o any issues btw.

-GN