Belt comming off issue

[2004sccobra]

So I'm new to the Protos family and I have getting frustrated with my 500

I watched the build video on belt tension but I cant seem to get it right or there in an issue that causes this problem that I am unaware of.

Issue: Bet comming off in flight.
When: full collective after lift off or after 45 sec of hover.
Trouble shooting: Checked tension multiple times, made sure belt was aligned with all the pullies, correct belt twist, gears all good, pinion tight on the motor shaft, belt is good.

This issue forced me to learn real quick how to auto! Not pretty but didnt crash or break amything.

please help or I will be forced back to Align.

[Mikej]

Where is your belt running on the main gear - mine was running a little high (top of belt level with top of pulley). I loosened the boom block and horizontal fin screws and lifted the back of the boom so that the belt now runs much closer to the middle of the main pulley.

Not sure if this is your problem but well worth checking.

Cheers,
Mike.

[2004sccobra]

When I get it to the ground the belt has always been below the main gear. I tried tilting the boom it up and down

[BHChieftain]

I've noticed that a slight adjustment of the tail boom block angle (you can rock it up and down) has a large impact on where the belt rides on the main gear.

Chief

Sent from my XT890 using Tapatalk 2

[tat2spyder]

make sure your boom is installed the correct way. (easy to install backward cuz the manual pics look that way) You want the slots in the front, hole in the back, and the logo on the starboard side face up. if the slots are in the rear, the tail can slide around, then your belt tension will change, and pop off the gears.

[2004sccobra]

Originally Posted by tat2spyder

make sure your boom is installed the correct way. (easy to install backward cuz the manual pics look that way) You want the slots in the front, hole in the back, and the logo on the starboard side face up. if the slots are in the rear, the tail can slide around, then your belt tension will change, and pop off the gears.

Cool ill take a look into that

[Ah Clem]

A friend of mine installed a second idler pulley on his Protos (I think on the other side of the frame).

His never came off again.

[crickr1]

Also check your motor mount. Your motor/pinion nrrds to be // to your main shaft. If the slots are worn on frame (more common on plastic frame then cf) your motor may have slight tilt.

Check idler pulleys as well. As bearings start to go bad they can get run out and cause belt to not align, and can also wear the groove they sit in on tail block as well as front idler mount.

[BHChieftain]

Any update if this has been resolved?
Chief

[2004sccobra]

Originally Posted by BHChieftain

Any update if this has been resolved?
Chief

Totally forgot about this.

So far I have had 3 full flights with zero issues. These flights were very lame. 80% power doing hovers and figure 8's. I got so frustrated with it that I tore the heli down to nothing and "re-built" it. In doing so I think I noticed the issue and it was a stupid mistake on my part . Basically the main shaft collar was not snug against the top bearing. This allowed the shaft and all connected parts to shift upward ever so slightly (a few mm) which casued the belt to slip off the bottom of the main gear.

[MolokaiBoy]

I am glad you found the issue. I have had my protos for a short while and I love how it flies.

Happy Flying!!

Les

[BHChieftain]

I'm glad you spotted the issue. I've had over 90 flights across two Protos and never had belt come off-- in the beginning I had the belt running really low on the main gear until I figured out I can adjust the tracking by the angle of the boom...

Chief

[dsduani]

Originally Posted by 2004sccobra

Totally forgot about this.

So far I have had 3 full flights with zero issues. These flights were very lame. 80% power doing hovers and figure 8's. I got so frustrated with it that I tore the heli down to nothing and "re-built" it. In doing so I think I noticed the issue and it was a stupid mistake on my part . Basically the main shaft collar was not snug against the top bearing. This allowed the shaft and all connected parts to shift upward ever so slightly (a few mm) which casued the belt to slip off the bottom of the main gear.

Just saw MSH has a new main shaft that uses an integrated locking ring instead of a separate locking collar. I'm going to switch on the next re-build.

http://www.helidirect.com/msh51080-m...os-p-24431.hdx

[2004sccobra]

I will be looking that route as well thanks

[j bomb]

Wow really?! MSH came out with those a couple of years ago and then just stopped making them and went back to the original design. Now they're back again...weird.

[tat2spyder]

I think your better of with the adjustable collar. If you use that shaft with it built in, you will have to shim it to get zero slop. Very important that part has no vertical play.

[2004sccobra]

Originally Posted by tat2spyder

I think your better of with the adjustable collar. If you use that shaft with it built in, you will have to shim it to get zero slop. Very important that part has no vertical play.

Yep! found that out. And mine was just ever so slightly loose

[BHChieftain]

I like the standard shaft without that lip. Just check the collar after every crash.
Chief