main gear shredding?

[chaveezy]

Looks like my main gear started shredding on the last day out at the field. The one way bearing on the clutch feels very tight and I can't seem to determine if I need to adjust the lashing between those gears (main gear and clutch bell pinion). I went ahead and ordered a Raptor upgrade 96/11 gearset and then a new clutch bell and updated clutch, with updated starter shaft. Anything to expect when doing this and how can I tell whether the gear lashing is correct or not?

Looked to me like an alignment issue but the only thing I could see was that the bottom bearing block on the main shaft seemed a little offset. Not sure what to make of this, why did they update the starter shaft and clutch? Was this a common problem?

[Raptor30_V1]

Hello,

My guts tells me, that often when gears strip or wear fast, it’s not necessary the quality of the parts itself ? Phantom1500 putted down very well (even in a vid) what counts as well.

As for an open discussion, let’s discuss openly what can go wrong here:

Parts quality: mainly the main-gear can have the following deficiencies..

- Unperfect roundness: this will lead to asymmetrical wear over the circumference (you will notice this on an oscillating horizontal tail movement)

- main-gear has warpeage from molding, this can have similar outcomes as unperfect roundness ?

- Conical form of main gear : as main-gears are easier to mold when the form is conical (to remove the molded part) .. this is normally only a few degrees, so shouldn’t be a real problem ..

- Teeth module and material strength: if this is an issue, try something we can trust, e.g. main-gear from ThunderTiger (if available)

Assembly:

- mainly related to gear-mesh (how much play inbetween gears?)
- all related axles being parallel to each other ?

If your main-gear wears fast, I would follow two pathes:

- if you know about how to setup for correct gear-mesh and axle alignement (you can not always just trust the MFG's tolerances?) and main-gear still wears very fast, I would definetly as next thing try a ThunderTiger main-gear (this applies only to JS-birds). Either your problem is no gone or you need to take a look as described in the following ..

- especially average to mid experienced mecanical guys should first of all take a closer look how to setup gear-mesh and to have parallel rotating axles (crankshaft – starter_assembly – main_gear). Search for Phantom1500’s vid how to do so – using the paper-stripe trick, you will be able to setup for a correct gear-mesh between main-gear and pinion.

True, using even a tuning ThunderTiger fan-hub (alumina) additionally improves the whole as run-out and balance becomes better too.

Best Regards,
Oliver

P.S: Take the new Outrage 90 nitro bird as example: many gears stripping but the question is why?Design deficiency or just non fool-proof setup/ assembly ?

[chaveezy]

Good points, I doubt it's a MFG issue, unless the gear just simply broke or stripped off during flight. It's obvious though that the clutch bell pinion gear and main gear are not making even contact, as I can see the wear marks and they're at an angle. If I lay the main gear down on its side, it sits about 3 degrees to the side (if that makes sense).

Gear lash (mesh) feels good, there is no play between the two gears, if anything they are making too much contact at the lower part of the main gear (hence the uneven wear). Not sure what to make of it, I guess with the new parts that will eliminate MFG defects (some what)

The setup of the parallel surfaces (starter shaft/main shaft) is what I think the issue is here, however there really is only a vertically slotted hole for the lower bearing block, so I'd either have to elongate some of the holes on the engine mounting system or main shaft bearing blocks. I could also shim the engine itself I guess but I didn't read anything in the manual about doing this so how's everybody else doing it?

[phantom1500]

Originally Posted by chaveezy

Gear lash (mesh) feels good, there is no play between the two gears, if anything they are making too much contact at the lower part of the main gear (hence the uneven wear). Not sure what to make of it, I guess with the new parts that will eliminate MFG defects (some what)

and there inlies your problem, a tight gear mesh is NOT a good thing, too much load on both gear, bearings etc. you need to have back lash in any type of gear train in order to stop prem gear wear.

I know there is an issue with the pinion gear being tighter at the bottom of the main gear more than the top. I had a tight spot in the gear mesh and after much study made a mod to shim the engine mount to move the motor away from the main shaft.

The gears being too tight also pushes the top of the motor shaft away from the main shaft changing it from being parallel to the main shaft to off a few degs as you can see.

PS, we are talking 90 size?

I don't know where is saw them but some where on the internet there are pre-made shims for the engine mount for the 90 but I cant find it. I just used 1mm carbon fiber sheet and made my own, you could also just use some 0.5mm flat washers and sandwich between the motor and mount block?

The only thing I have changed for raptor was the fan assy....sweet mod and the gov magnets no longer exit the heli at bullet speed!

[chaveezy]

Actually this is a 50 size but it's the same, good job on the shims, I'm going to rig something up to fix this.

[Raptor30_V1]

Hello,

I'm aware, that we are speaking about a Frenzy-50. I remembered some posts here, where some people included pictures showing different problems and mods. This included even the mod when using Raptor parts (fan and main-gear). As far as I remembered, in case of different make fan-hub, the holes for this mod had to be changed in the vertical direction.

Let's not discuss the mod above using other parts, than first try to get the most out of the parts supplied with the kit. I remembered the design of the F-50V2 to be pretty the same as of the F-90V2, although I do not remember to have seen some horizontal slots (instead of a hole) for the positioning of the starter-assembly (assembly including: clutch-bell/ housing, bearings, pinion, starter-shaft) by 4x M3 screws. So if your F-50V2 doesn't have the possibility to horizontally adjust your starter assembly, you will have to modify the side-frames in order to set up the gear-mesh well.

Using the vid from Phantom1500 (many thanks again) - I did the following:

The engine's crankshaft is parallel to the main rotor shaft (means engine-mount-holes in the side-frames are well made). But - as Phantom1500 described here on HF for the F-90 - the engine itself maybe needs to be moved a remarkeable amount to have the clutch being centred in the clutch-bell. The starter-assembly including the clutch-bell itself, needs to be aligned in the slots (side-frames) to be parallel as well to the main rotor shaft and at the same time the pinion above the clutch-bell needs to have the right gear-mesh with the main gear. Let's start with the positioning (horizontally and angle) of the starter-assembly to get the starter-assembly parallel to the main-shaft (no angle) and setting-up the right gear-mesh (horizontal adjustment) inbetween the pinion of the starter-assembly and the main-gear (main-gear is not adjustable horizontally). If this is made correctly, in a second step the alignement will be inbetween the starter-assembly (positionnend well already) and the engine assembly (engine assembly: engine, fan-hub, clutch). Doing this we do not only try to have no angle inbetween engine crankshaft and starter-shaft, then as well to have the clutch of the engine-assembly be well centred inside the clutch-bell. This is the occasion as well, to check, whether you will use your engine washer (delivered with most engines) or not, to have the clutch later on flush to the clutch.



So let's see in more details, how you can proceed (described for a Frenzy-90):

1.) Main-gear and tail-belt-gear completely installed on the bottom of the main-shaft - BTW, the tail should be mounted at this time as the tail-belt needs to be mounted on the (black) tail-belt-gear. Twisting of the tail-belt in the Frenzy-90 manual seemed to be wrong? Check this for the 50 size as well ..

2.) Install the alumina engine mount - I did not mount the plastic vent-channel so far, to see better how things align ..

3.) Install the starter-assembly (w/ the clutch bell at its bottom) and use the 4 screws w/o tightening them yet so they just help to hold the starter-assembly in place

4.) Cut a stripe of paper (typically type: 80 grams/ square meter) and feed this stripe inbetween the main-gear (just turn the main gear and feed the stripe) and the pinion of the starter-assembly (pressing both assemblies together) .. and don't completely tighten the 4 screws of the starter-assembly, but tighten them the way the starter-assembly doesn't move easely .. remember, there should be no angle of the starter-assembly (parallel to main-shaft) ..

5.) Mount the engine-system (engine w/ fan-hub and clutch) on the engine-mount and loosely use 2 of the screws to hold in place..

6.) Now the final games is, to move the engine-system forward & backward (limited backwards by the engine-mount) having the unit parallel to the main-shaft and the clutch centered well in the clutch-bell .. use thin-metal sheet to feed the gap you found ..

7.) Take the occasion to check, if the clutch is flush within the clutch-bell and therefore is not to deeply inside the clutch bell nor outside .. at this occasion you will find out quickly as well, if the engine-washer (inbetween fan-hub and engine) is required or not ..

8.) Remove engine and install vent-channel - if you removed it before for alignement purpose (no need to tighten this screws yet completely ..

9.) Cut 2 pieces of metal sheet you found to shim inbetween engine and engine-mount (each of with 2 holes of 4mm bore) on each, put some loctite on all screws (engine, starter-assembly), first tighten the starter-assembly screws again (not completely), put the paper-stripe inbetween the gears again, tighten the engine completely to the engine mount and being matched in the clutch-bell of the starter-assembly .. press the starter-assembly against the main-gear (thanks to the slots) and having the starter-axle being straight as well, tighten it now completely ..

10.) Take your starter and turn it a few times to check the whole alignement - helps to settle the whole thing as well.. if not done yet, tighten the screws of the vent-channel ..

Having done all that, you have done almost done the best you could .. if the main-gear now is still PITA, then it either is because of main-gear warpage, main-gear material being to soft and teethes stripping to easely (use TT gears if compatible), or simply you should tune your fan-hub-system for balance and run-out ..

Hope this helps a little bit - either way it's best to watch the vid Phantom1500 made.

Best Regards
Oliver

P.S: Using this procedure its best to have the bird in front of you and you will easely - step-by-step - understand what needs to be done in which sequence ..

[chaveezy]

Excellent clarification! I did watch the video and the only thing I had left out from my original idea of "shimming" the engine was that I would need to elongate the holes (horizontally) to the starter bearing block, in the side frames that is.

I have a 96T/11T Thunder Tiger gears coming from A Main, as well as a new clutch bell and starter shaft, so when I get these parts I'll do this mod to set the gear lashing/mesh to a more suitable specification.

I appreciate the responses, this has helped very much and I am SURE that it will solve the problem.

Cheers!

[Raptor30_V1]

Hello Chaveezy,

Thanks to Phantom1500, he was the first one to address this issue taking his time to make a vid !

Regarding your TT main-gear substitute: if this is a good replacement, please post the ThunderTiger (TT) part number of the gear you bought (PV0XXX), as TT has lots of different gears and this will simplify life of others.

As far as I remembered from my Raptor50-V1, the gear ratio was 1:8.5 ?

Best Regards and keep us informed about your experiences after looking over it,
Oliver

[mattsergo60]

SPARX- has a post in this section titled "Frenzy gear ratio 8.5:1 vs 8.7:1"
He is running a 96Tooth main gear and 11 tooth pinion ( sold as a pair)
$25.00 and part # is PV0518
I have not had any gear issues as of yet , But would like to know how others like this
96/11 combo.

[chaveezy]

Originally Posted by mattsergo60

SPARX- has a post in this section titled "Frenzy gear ratio 8.5:1 vs 8.7:1"
He is running a 96Tooth main gear and 11 tooth pinion ( sold as a pair)
$25.00 and part # is PV0518
I have not had any gear issues as of yet , But would like to know how others like this
96/11 combo.

Installed this same exact combo last night, hovered it and reset my main rotor blade pitch today, seemed to lift a lot sooner, but tomorrow I'll be ringing it out a little to really see how that is going to affect the heli. Also I installed the updated starter shaft and clutch. I was going to shim the motor but when I got it all installed it looked a lot better and much more even as far as gear mesh was concerned.

With the addition of some Curtis Youngblood 3mm Stubz paddles we'll see how she handles tomorrow, should be fun!!!!

[chaveezy]

Well, flew it about 10 minutes today total and toasted my OS 50 Hyper motor, guess it leaned out and damaged the piston/ring/sleeve. Oh well

Guess I'll go find an OS 55HZ for it now

[mattsergo60]

That sucks. What are you gonna do with the toasted 50 hyper?

[chaveezy]

Originally Posted by mattsergo60

That sucks. What are you gonna do with the toasted 50 hyper?

Don't know yet. Parts are going to cost $100, that's for piston/ring and sleeve. Then I might as well put some new bearings in it since the rear bearing has some corrosion on it. I bought an OS 55 HZ the other day and I'm waiting for that to come in. Comes with a Carb Smart w/ servo as well so that should keep that one safe.

To make matters worse, I was pulling the clutch and fan off the 50 Hyper and the one way bearing on the "updated" clutch is TOAST. Bearing cage is completely broken apart and the rollers are falling out. One flight... Seriously!? Ah, well whatever, guess I'll go back to the stock clutch and starter shaft, didn't really notice any difference anyways and the clutch engagement was still way too soon.

My Pantera seems to be looking better and better though, always saves me for a few peaceful flights every time I'm out at the field whenever the Frenzy takes a dump.

Maybe I'll just get rid of it and build another Pantera with this drivetrain/electronics package.

[chaveezy]

Well, got the OS 55 HZ installed along with the CarbSmart setup, brand new motor and running it at 2 turns open on mid and high needle so it's very rich. Carb Smart is on 100 degrees and it never even goes half way, OODLES of power though, thing just tears up the sky.

I have a Throttle Jockey Pro governer sitting here for it as well but I'm hesitant to install it with the optical pickup it came with. There is also the magnetic one but I don't have the magnets. Also once I get this governer installed I need to tach it, and there is really only one or two guys with tachs at my field so I may have to just bite the bullet and buy one.

I didn't notice any issues with the 8.7:1 gear ratio that I have installed right now (96/11T), would like to keep the head speed down to about 1900-2000 with it though because it really doesn't take much to get it flying with these gears and every once in a while when flipping, or flying inverted I hear the motor start to scream for a second (might try to adjust my mid point throttle curve tomorrow and see what that does).

I was having some issues installing the JR micro servo for the Carb Smart but I ended up making a small mount out of some plastic I had and installed it in the circle on the right hand side of the plane in front of the engine. I'll get a pic up, but it worked good!

I also did get a warranty replacement "updated" clutch from A Main Hobbies, they really have great customer service, didn't even have to send the damaged one back, however, I went ahead and re-installed the stock clutch with stock starter shaft for now. This darn clutch grabs so soon, I can't even get the engine to idle without it grabbing every few rotations, really is annoying. Might try to upgrade to a TRex 600, or maybe Raptor 50 clutch and clutch bell, I heard you can do that.

[Raptor30_V1]

Hello Chaveezy,

Cool, I guess things are doing well now

There's a further alternative, to the use of a gov - this is especially interesting, as you might be still tuning your carb's needles and the gov you use needs a tacho (I dislike govs where you need a tacho, as uncomfartable and dangerous). When your pitch- & throttle-curve is set well, you can use a cyclic-to-throttle mix, increases throttle when a cyclic inut is given. Don't be afraid to use some 30% values and higher of this mix - if in doubt what's happening, just take a look at the carb when your bird is on the ground and w/o having the engine running, make some full swash-inputs for ail & elev. BTW: there is a gov-sensor from Spektrum being installed on the engine's backplate, nice thing (e.g Amainhobbies sells them) but you need first to check, if this gov-sensor is compatible with your gov.

Carb-Smart: Had one too, but didn't like it after a while, as:

- the genuine sensors cost a lot and are prone to fail (meanwhile there's a DIY-kit from Aerospire for little money and using arctic silver epoxy the vibration issue might be resolved too)

- you can't adjust the desired-temperature depending the flight-mode (e.g. when switching on your Tx .. meanwhile the Multigovernor Pro from Aerospire has this feature)

- when you hoover .. your Carb-Smart will lean your main-needle to reach the 100 degrees.. depending now, how much way to travel for the lean side you set-up, you can have later a higher than required hoover temp (100 degr. Celsius for hoover makes no harm but IMO is unnecessary high) .. so Carb-Smart works well if you mainly torture your engine all the time (mid to hard 3D) and you're not a sports-flyer and hoovering for a long time ..

Best Regards,
Oliver

P.S: The CSM Carb-Smart was the first device to control needles .. but there's a better product from CSM .. the CSM Cyclock .. if you do not have/ want FBL you can use a Cyclock to correct for swash-interactions and phasing and even getting a way better servo-resolution.

[Groove]

Chaveezy,

I was about to throw mine in the garbage as well…

Last year, I experienced the same problem you have. My perfect running engine seemed to be way down on power, and it seemed to run really hot. I tore up a few main gears, some half way through their first flight all with perfect gear mesh. I found the gear was melting, not shredding. The gears in fact were very ‘true’ not out of round at all. I also went through bearings on the starter shaft. They were torn to shreds and fell apart, they too obviously failed because of heat. I determined the cause to be excessive heat built up in the clutch.

The fix...

· Thunder tiger 50 clutch bell... the original rubber lined frenzy clutch slips continuously. (slip=heat and lost power)
· Ceramic bearings on the starter shaft... Not necessary, but while it's apart, for just a couple bucks. you may as well lose some friction. (A-main has them)
· Make sure your clutch bell has a LITTLE bit of play between it and the top of the clutch. You need a bit of relief when everything heats up and expands slightly. Otherwise you are going to put unnecessary stress on your motor bearings and starter shaft bearings. This equals heat and heat equals failure.
· Get the mesh right. The frenzy has elongated holes in the frame at the starter block. Very simple to adjust. If you have to much of an angle between the motor and clutch bell, you will need to shim, however all should fit pretty nice.

After these pretty cheap mods, I picked up a LOT of power and the engine now runs cooler. I have a RedLine .53 in mine, and can run 2250 on the head with no prob. You should be able to scream with your OS 55.

IMHO, this is one awesome little bird ~after you fix some simple problems. So I’d say, for $150 + less than $100 in mods (metal swash, new clutch, some ceramic bearings), you can’t beat the deal. Plus… a catastrophic crash will only cost you $150 bucks for a new kit. I bought 3, 2 are ready to fly and 1 is in the box for parts. I chose to go sans flybar…

I hope this helps,

Groove

[Raptor30_V1]

Hello,

Just for curiuosity: on my JS F90-V2 the clutch-liner was not a liner, than a wide tube cut to the width corresponding the height of the clutch-bell inside. The *liner* seems to be made of some strange sort of material comparable to shrink-tube ?

Is this made the same for the F50 ? I didn't trust the material, as most other clutch-liners I had, either were rubber-style or fiber-style..

So maybe it's not the clutch-bell (e.g. not being round) than simply the liner inside ? Using TT Raptor 50 clutch-liner the fix just would cost some 3 buggs, some epoxy (long cure) and a little bit of electric tape to wrap around the clutch to get a simple tool to hold liner in place when epoxy is curing over night. The gap inbetween clutch and clutch-bell is fine if from 0.15mm to 0.25mm (each side speaking).

For the Frenzy-90 V2 I used the Raptor 60's liner, seems to work very well when glued in with epoxy (12 hours cure).

Best Regards,
Oliver

[Groove]

Raptor,

The 50 is the exact same liner as the 90, just sized for a 50. Yes, just changing the liner would work... But, for 13 bucks, I'd just buy Raptor unit already completed.

To each his own... I tend to be somewhat lazy.

[Raptor30_V1]

Hello Groove,

No problem with being lazy - or at least that honest to admit of being lazy ..
My point is, that for many people buying budget, it won't make sense to buy a bargain bird for USD 150.- and then to have to replace some parts being already 2-digit percentage of the whole kit price ..

I know what you mean, as I exchanged the fan-hub on my F90-V2 by a Raptor-90 fan for Yamada engines too. Required ? Nope, but just my personal wish to have a better run-out and balance of the system.

Best Regards,
Oliver

P.S: There are students or other people in this hobby with the need to flip any coine twice, my recommendations often aim to this people