Tail belt problems

[rcmike]

Hello Everyone,

I have had my Raptor 50 for a couple of years and for some reason lately it has been making a dinging sound like the belt it hitting the inside of the boom. I tried tightening/loosening the belt but it still does it. I replaced the belt and the gear on the tail shaft because I thought it might be skipping on it. Well today the belt jumped off of one of the pulley in the front. I fixed it and tigtened the belt and it did it again! Does anyone have any ideas what else to check? All the pulleys look fine and I have almost ran out of things to check.

Thanks,
Michael

[johndale]

:D Are you sure your mast bearings are good and also your freewheeling unit is not worn? When I had a dinging sound in my 50V2 it was in the clutch bell. :shock: just some ideas that things that has happen to mine.

[esmith]

Have you checked the tempeture outside? Not sure about where you live but it's winter here and taking the warm heli outside means the aluminum tail boom will shrink in the cold and loosen the belt enough to cause the problems your having.

Just a thought. Hope it helps.


-eSmith.

[HelicopterJohn]

Hi Michael,

As stated temperature difference could be an issue.

I live in Florida so that is usually not an issue for me. Some time in the past I was having the same issue with the belt tension changing. I also run a tail rotor speed up gear in my Raptor 50's and tail belt tension is very important to keep the belts from shredding.

I did 2 things that have worked well for me.

First I made an aluminum gear front hub and got rid of OEM white gear and used the old red gear from the V1 Raptor 30/50's.

Secondly, I purchased "white" powdered coated tail booms from Rick's R/C Helicopters. The powdered coating makes the O.D. just "slightly" larger and provides a better grip on the tail boom when you tighten the 4 bolts that hold the tail boom in place.

The second item is easily purchased and the price is right and I would recommend you give one a try.

Just something you might want to consider.

:)

[rcmike]

I think I figured out what it was. The white belt gear had quite a bit of play in it. It would turn quite a bit on the main shaft. I tightened down the bolt until it wouldn't move and the dinging stopped. Before I had the belt so tight it was robbing power. After tightening the bolt I was able to loosen the belt quite a bit and it still didn't ding. I am not 100% sure why that caused the dinging but it fixed it.

[HelicopterJohn]

Hi Michael,

Yep, the OEM white gear is a REAL JEWEL.

The plastic the white gear is made of is soft, fits sloppy on the hardened sleeve and the inner diameter (which is too small) tends to drag on the aluminum hub of the one way bearing. Tighten it too much and it warps the hardened sleeve and if you leave to too loose it will cause belt drive issues. Some pilots leave the lower Jesus bolt a little loose and (in my opinion) it will allow the lower Jesus bolt to create a shearing action which (could and has) resulted in breakage of the lower Jesus bolt.

If you have any type of crash I would recommend that you replace both the upper and lower Jesus bolts (no matter what they look like) if you are running the OEM 3mm bolts.

I have a few machine tools and I got tired of all that nonsense. I enlarged the main shaft cross drill holes to 4mm for the top and bottom Jesus bolts. I drilled the upper head block to fit a 4MM bolt. The lower hardened sleeve was difficult to drill. I used a 5/32 cobalt bit and dressed the holes with a dremel. I also made a new hub from aluminum and used the old Raptor 30 V1 red gear. I can now run my belt as tight as I wish and still have minimal drag as my new hub properly supports the newly installed red gear.

I realize the everyone doesn't have the tools but just thought I would share what I have done with others.

Just don't forget my advise about changing the Jesus bolts after a mishap as it may cost you another mishap at a later date.

1-4-06 Added a picture of my custom hub.

:)

[rcmike]

Yep, I have changed the bolts out recently. I may see what I can do with the gear to fix it better. I may even have an old red gear laying around to try. I had an aftermarket driven tail upgrade on my old V1 Raptor but I gave it to someone when I changed to a V2. Maybe I should have kept it. :shock:

[HelicopterJohn]

Yes, you should have kept the old driven tail upgrade.

I purchased a couple of them from Rick's when they handled them. He stopped carrying them when the new V2's came out. (Big Mistake) in my opinion. In as much as I could no longer buy one I made my own.

Sometimes the newer version is not always the best.

:)

[flyinfool]

I have the "dinging" noise right now. It is due to my having just put in a new clutch that is set a little to tight.
what I believe is happening is that when the clutch engages there is a jolt to the driveline but the load slowes the motor down enough to disengage the clutch and unloads the drive line but the lack of load allows the motor to speed up and grab the clutch again.
I am experimenting with a new very grabby clutch liner material.
A couple of warm starts might fix it.

[HelicopterJohn]

Hi Jeff,

What clearance are you running on the clutch? I turn mine on a lathe and set the total clearance to .012 or .006 per side.

I can remember the first dinging sound that I heard was when I had two many twists in the tail belt and the belt teeth were hitting in the middle of the tail boom. DAH!!!! :arggg: 1/4 twist in the tail rotor drive belt is what you need.

:)

[flyinfool]

I also turn mine on the lathe and usually go for the same .006 per side.
In this case I was experimenting with a new liner material so I started at .003 per side.
.003 is just a little too tight. I also never even thought about the shrinkage at 30°F that brought it down to .002. I will open it up .001 at a time to find the optimum clearance for this material.

[HelicopterJohn]

Hi Jeff,

Another thing I found on the Raptor30/50's is that the motor alignment in the frames has a lot to do with clutch life and (drag) as it pertains to clutch engagement.

Remind me when we talk and I will tell you how I install the motor.

:)

[rcmike]

Thank you HelicopterJohn! I got a new white gear and the dinging is gone. I didn't really look too closely at the old one until you mentioned it. After I did look more closely at it I noticed it would rock back and forth on the jesus bolt. It must have been setting up a vibration on the belt, causing it to slap the boom. I don't know how many times I heard, "the belt is too loose" :roll:

[HelicopterJohn]

rcmike,

Glad to hear you got your problem sorted out.

:)

[Yellowjacket]

Another problem that I had with my 50 Raptors when I was sill running them 4 years ago.
The main shaft is very soft and having a hardened bolt in time it would elongate the hole that goes thru the main shaft and one way bearing. It would wind up causing the bolt to break.

I ran a metal head I guess the way it would clamshell around with a very tight fit I never had any problems on that end.

I finally started drilling the main shaft and one way bearing sleeve to 4mm.
This stopped the bolt from breaking but was just a band aid to the problem.

I was afraid the excessive slop would cause radio problems so I had a 30 X-cell main shaft that was hardened. I had it cut and drilled at a local machine shop to fit.

This solved the problem.
I think the slop down there is what was causing the white gear to slop out so quickly.
I built a few V-2’s for friends and had to dremmel out some material inside the white gear and greased it to turn smoothly.

These 50 worked very well.
Now you can buy a Maverick hardened main shaft from Heli Proz for 5.99
I haven’t tried them but I’m sure other pilots were having the same problem or they would not have come out with it.

Bill