600e Pro Tail Blow Outs

[mdz12345]

Has it been determined if it is absolutely necessary to slot the frame when performing the tail gear change? I just purchased the new Trex600E pro DFC kit that includes the performance booster package (750MX motor, 14T pinion,118T main gear, ect). I am going to replace the following parts to allow me to lower my head speed to around 2000 RPM.
1) Replace the motor mount with a "KDE Universal Motor Mount and Pinion Support," which will allow me to use a 12T pinion (Align H70062).
2) Replace the M0.8 autorotation and torque tube front gear set with the M0.6 version
Align 180T autorotation gear (H60020AA), Align 40T Torque tube front drive gear set (HGNG001XXW).
I am mainly a big sky flyer with the occasional barrel roll, loop, and inverted hover. I just hate drilling holes in a brand new frame.

[Smoggie]

Consider this change carefully. The stock M0.8 torque tube front bevel gears seem to be very prone to stripping even driving the tail at stock low ratio (see thread below this one). I think the higher power motor and stiffer main gear doesn't help with this problem.

Increasing the gear ratio which will put more load on the already marginal tail drive-train and fitting weaker gears further compounds the problem. Seems like a recipe for disaster to me.

[taoY]

The gear mesh will be less than ideal when you switch to the mod .6 faster tail gears. Slotting the frame allows you to adjust the gear mesh. Highly recommended if you switch to faster gears.

[mdz12345]

Originally Posted by Grumpy_Old_Man

Consider this change carefully. The stock M0.8 torque tube front bevel gears seem to be very prone to stripping even driving the tail at stock low ratio (see thread below this one). I think the higher power motor and stiffer main gear doesn't help with this problem.

Increasing the gear ratio which will put more load on the already marginal tail drive-train and fitting weaker gears further compounds the problem. Seems like a recipe for disaster to me.

Thanks for the quick response. Just to clarify, do you think it is better not to change either gear ratio? The reason I want to change to a 12T pinion is to increase flight time. If I understand correctly, ESCs run more efficiently the closer they are to full throttle. So if I was to change my pinion and use 100mm tail blades with the stock tail ratio, would this be a better alternative?

[mike d1]

I run a 12t on mine, but I run it to get the headspeed down cause I just felt like the 2400-2500 stock gearing was way to fast. I get almost 7 minutes flying out of mine and batts come down at 3.82 most times. Best part is my esc and motor are very cool too.

Mike

[Smoggie]

Originally Posted by mdz12345

Thanks for the quick response. Just to clarify, do you think it is better not to change either gear ratio?

All I'm saying is that the tail bevel gears are already a weak point even on the standard heli. fitting weaker gears on the face of it sounds like it's asking for problems. If others have done it without problem then by all means give it a go but at the very least make sure you do whatever is required to get the mesh nice and tight.

FWIW I regularly fly for 7.5 minutes on 2700mAh batteries and stock gearing all round, 2100RPM headspeed. 8 minutes would be easy on 3000mAh batteries. The tail blow out thing is really only going to be a possible issue if you are flying hard 3D, but if you fly hard 3D then flight times will come down regardless of headspeed.

Here's a 7.5 minute flight on the 2700mAh battery:

Trex 600 DFC flying at Balgownie again (7 min 41 sec)

[mike d1]

I'm curious, has anyone who has bought the kde kit actually stripped anymore gears? Or are the people who are stripping them just flying stock helis?

Mike

[338federal]

I have booster pack and m0.6 tail. Kde tailcase support that i can change the mesh with auto rotation gear. 105mm tailblades. I fly only sport flight. The gear mesh is very tight. I hope it holds and not stripp the gears. Happy flying dudes.

[Smoggie]

Originally Posted by mike d1

I'm curious, has anyone who has bought the kde kit actually stripped anymore gears? Or are the people who are stripping them just flying stock helis?

Mike

The KDE kit is nice and all, but really it's not required unless you like the 'bling value' of the machined support frame.

All you really need is a few 12x15x0.1mm shims, which you can pick up on eBay (the RC car boys use them), they only cost a few bucks. The shims look after the bevel gear mesh (I used four to remove all play). To tighten up the mesh with the auto gear all you need is a tiny round hand file to slot the holes in the frame a little, it only needs about 0.5mm.

[mike d1]

Well I just find it odd people constantly talking about the stripping, but I wonder how many have bought the kit and are still stripping, anyone? I just think the fix is really easy, with kit or by slotting and shimming, yet seems every other post in this forum is about gear stripping. I bought the kit eventhough I've never stripped one set, I guess just for peace of mind.

Mike

[Smoggie]

Originally Posted by mike d1

Well I just find it odd people constantly talking about the stripping, but I wonder how many have bought the kit and are still stripping, anyone?

Two things have to be considered:

1. The vast majority of people are running un-modified 600's. The number who have done the tail gear mesh mod or fitted the KDE kit are a small minority.
2. It's human nature to only report when you have a problem, people just dont generally post "hey, I had another flight today without stripping a tail gear".

Anyway, After stripping bevel gears in flight I've just added some shims and slotted the frame holes to remove all 'slop' from the gears. So I'll certainly report back on results in the other thread I started (slightly drifting off the main topic of this thread). I'm hopefull it's fixed the problem but I'd not like to put money on it.

[Smoggie]

Originally Posted by mike d1

Well I just find it odd people constantly talking about the stripping, but I wonder how many have bought the kit and are still stripping, anyone? I just think the fix is really easy, with kit or by slotting and shimming, yet seems every other post in this forum is about gear stripping. I bought the kit eventhough I've never stripped one set, I guess just for peace of mind.

Mike

Seems that if you fly hard then even after shimming/slotting to tighten the mesh the tail drive gears are still prone to failure: https://www.helifreak.com/showpost.p...4&postcount=33

[rc_corner]

T-REX 600 Tail Gear Problems Status Update With Video and Resulting Crash

Once again repairing the helicopter for the 10th time to try and identify and resolve this issue on my own as Align has not been responsive. After making the following changes and adjustments, I was able to get two flights before the tails gears self-destructed crashing the helicopter:
1. Added a .5mm shim spacer to the front torque tube gear.
2. Added a very small shim (did not measure) to the bottom of the crown gear to obtain
a 100% gear overlap with the torque tube gear and eliminate the up/down slop.
3. Used a white torque tube gear to better absorb vibration with a little flex and a black crown gear, which is the weakest component where I believe the problem initiates.
4. Oversized frame holes and added washers for strength to improve alignment with the auto-rotation gear.
5. Changed the IKON governor gain from 40 to 10.
6. Changed the IKON tail D-gain from 40 to 65.
7. Changed the IKON Input Tail Dynamic to 5.
8. Changed the IKON proactive Tail gain to 5.
9. Changed my flying style to be much more conservative and less aggressive (this is a little boring but better than destructing the tail gears on every flight), see attached video.
I am sick of this helicopter as I have spent over 1,000 in repairs to try and fix this problem with minimal success. This is a good helicopter with exception to the tail gears as they will always self destruct under hard to moderate 3D. For basic 3D this helicopter is fine. I can’t believe that Align refuses to acknowledge and acknowledge and fix this problem. The failure today was the standard tail gear failure between the crown and front torque tube gears.
10. Everything on the helicopter is stock including the gear ration and 95mm tail blades, which exhibit the tail delay against the torque and frequent tail blow-outs.

Link to my second flight after rebuilding the helicopter again that ended in tail failure and several hundred more dollars in damage is as follows:

T-REX 600 Tail Gear Problems Status (2 min 6 sec)

If you play the video in slow motion, you can see exactly where the failure occurred. Problem begins just after completing the tic-tocs, but are not from the tocs. I am pushing out with nearly fully negative pitch while pirouetting against the torque (clockwise rotation) of the powerful 750MX motor. Note that after hearing the gears break the motor torque caused the pirouette direction to change from clockwise to counter-clockwise with the torque of the motor. Without a design change, the only way to prevent this problem is to pirouette with the motor torque direction (counter-clockwise) when applying significant pitch. Due to the surface area of the crown and umbrella gears, they cannot withstand and hold-up to the opposing load of the 750MX motor torque. The solution would be to adapt the 700 gears, which have a much larger surface area, but unfortunately the 700 tail boom mount holes do not line up with the 600 frame so the only option is a change to our flying style to only pirouette with the torque of the motor (counter-clockwise) and avoid any similar moves that place a significant load on the tail gears. When Align makes changes such as incorporating the larger power plant (750MX), they should better test the helicopter and make adjustments to accommodate the additional motor toque such as increasing the surface area of the gears. I will attempt to contact Align again for help with this issue, but to-date, they have been uninterested in helping us resolve this issue.

[celltech]

I don't understand all these problems. I run mine all stock at 1950 and never have problems. Granted I'm just a sport flyer and don't smack the heli.

[Smoggie]

Originally Posted by celltech

I don't understand all these problems. I run mine all stock at 1950 and never have problems. Granted I'm just a sport flyer and don't smack the heli.

I'm just a sport level flyer to but i maneged to wipe out my bevel gears. Too high a gain on the governor was undoutedly part of my problem but as I've just posted in the other thread i thing the upgraded 750MX motors fitted to the new version of the 600 DFC Pro are part of the issue. As noted above, massively increased torque requires massively increased thrust from the tail, which in turn massively increases stress on the tail drive.

Align made the main gear much beefier when the upgraded to the 750MX, the tail drive stayed the same... It doesn't take a genius to spot the potential weak link.

[celltech]

Originally Posted by Grumpy_Old_Man

I'm just a sport level flyer to but i maneged to wipe out my bevel gears. Too high a gain on the governor was undoutedly part of my problem but as I've just posted in the other thread i thing the upgraded 750MX motors fitted to the new version of the 600 DFC Pro are part of the issue. As noted above, massively increased torque requires massively increased thrust from the tail, which in turn massively increases stress on the tail drive.

Align made the main gear much beefier when the upgraded to the 750MX, the tail drive stayed the same... It doesn't take a genius to spot the potential weak link.

Yeah you are probably right. I am running the 600MX that came with my super combo and using Castle's recommended settings on my ESC.

[watdazit]

I think I just joined the stripped gear club. A new stock standard 600 Pro running 2300 head speed and I generally just wander about the sky. On my second flight the heli was flying level across my front when suddenly there was a bang and the heli spun around, I hit throttle hold and attempted to auto in. I had stripped front and rear umbrella gears, a bent boom and torque tube, a broken skid and one delaminated tail blade and the other tail blade broken.

I had not read this thread before this and I thought the tail blades had delaminated.

With the talk about the size of the blades I would make an observation that to obtain a stable hover the tail blades needed a lot of pitch. More than I would have expected.

The original gears were white and when I ordered replacements they were out of stock. When they came into stock the replacement gears were black and appear to be a different material. One might question if Align have beefed them up. If they have, it would have been nice for them to advertise it. I can understand why they wouldn't....that's business life today I guess.

This is my fourth Trex and the first time I have had problems. I still think Align generally make a good product and I would still recommend them. I have Furion and Compass helis and do not consider they are any better than the Align and in fact the way the Align is designed to go together it is superior to them.

[BigEddie]

I also just had a shared experience on a spool -up in my garage!
Std 600MX with 80 AMP ESC. Ran up the motor in normal set at 1900 on first battery.
Checked Ikon Stabitliy with 3ft hover. Set down and upon restart gears stripped.
NO Tail bounce or any large movement in tail.
So off I go to the repair/upgrade exchanges!

[Smoggie]

Sadly the new black gears don't cure the problem, it was black gears that I stripped and I'm only at sport flying level, no 3D. In fact I'd only recently 'upgraded' to the black gears having never had any trouble with the white ones.

It's definitely worth adding some shims to tighten the bevel gear mesh and slotting the holes in the frame to tighten up the straight cut tail gear as that can strip too. Also if you are using the Castle governor make sure the governor gain is set below 15.

[watdazit]

Thanks Grumpy. I might wait and see what happens with this set of gears. I might lower the headspeed as probably like you I am not a stick banger. I presume when you say shim the gears you mean the gear that the torque tube slots into so it pushes the gear harder against its mate?