450 Align Trex 450 Pro V2 Front Gear Torque Tube Assembly Broken Teeth???

[Bruno]

I just finished building the TREX 450 PRO V2. I started flying the Heli today. I do have some experience. Just kinda hovering on a windy day. A fly landed on my arm and distracted me (lol). The Heli was close to the ground (about one foot) and I brought her down a bit hard. She still has training gear on. As she spooled down I heard a ratcheting noise. The teeth on the front long umbrella gear and the teeth on the torque tube gear which meshes with the umbrella gear were broken (about three gear’s teeth broken, right where they mesh). I have examined the Heli under magnification and cannot determine how this happened. There are no stress cracks anywhere that would indicate that the tail boom flexed causing the shearing. I am perplexed. Can anyone enlighten me as to how the gears may have misaligned with such minimal force causing three teeth to shear.

All original Align parts. Thanks.

 

[Tony]

All I can say is welcome to torque tube. The force of landing too hard will cause the boom to flex and it will take out the teeth. If the tail blades hit the ground, no matter how slight, it will strip the teeth. It's the most fragile part on the helicopter and it is suggested to order multiple sets because you will need them.

 

[coolgabsi]

That's exactly why beginners don't like Tt.. I made my rear of the landing gear higher so the tail rides higher and less chance of hitting tail bladesz


But you are training gear right now. And yes it does happen. All it needs is a little bit. That's why I also prefer to chop the throttle 6incjes off the ground and do a tiny weeny auto... Less forces when no motor churning it. And so lesser chance of stripped gears

 

[breeze400]

As stated above, TT's are not for beginners. The slightest ground strike will result in stripped gears! I now am so preficent at changing gears that I carry a few extra sets with me to the field and it takes me 5 minutes to change them. If I were you I would take a couple of Popsicle sticks and glue them to the tail fin to get it off the ground some.

 

[Bruno]

Is it possible to remove the gears from the shaft or are they press fitted?
Thanks.

 

[Tony]

You can remove the gears from the TT shaft, but not the shaft that runs vertical in the very front that runs on the auto rotation gear.

 

[stokke]

I have ground pounded mine a couple of times, but no stripped teeth. Guess I've been lucky

 

[Bruno]

Waiting on my new gears. Thanks for the feedback. Very helpful.

 

[murankar]

Yes if you get multiple flights after a harder than light landing you are on borrowed time, enjoy it while you can because it wont last long.

 

[breeze400]

When you get new gears order them in sets of 3 there alot cheeper that way!

 

[Bruno]

So...I was able to pull the umbrella gear off the front grear drive shaft. I cut away the excess glue-epoxy and used my ball link pliers to basically slip the gear off the shaft. It actually came off with moderate amount of force. When the gear got to the end of the shaft I used the ball link pliers and another set of pliers with a curved grip and pulled the gear off the shaft. The shaft has a rigid/grooved length equal to that of the inside of the umbrella gear. Tarrot sells replacement gears for like $2 per gear. I plan on pressing the replacement gear on the shaft with some CA. I will make sure to measure and confirm placement in order to confirm accurate gear mesh.

It's a bit of work but does seem do-able.

I also have an assembled shaft to use and to reference for gear placement.

Interestingly, I have not found a replacement auto-rotation position gear for that shft assembly. Probably because they tend NOT to shear teeth.

 

[breeze400]

Glue, ca? That should be a press fit! Pictures please! Before you glue something you shoulden't! On mine you take the TT off the plastic mount and place it in a vice and press it in.

 

[Tony]

If you are talking about the gear below, you will purchase the whole thing together. The ones that look like they fit over something go to the shaft of the TT. Do not try and press a gear onto this type of shaft, you are just asking for a crash.

As pictured, the gear on the left will have two bearings on the outside of it. It will go into the block horizontally. The gear to the right is the one that sits the furthest forward in the tail block and meshes with the Auto Rotation Gear. You can't use the gear on the left on the shaft on the right!

 

[breeze400]

Tony I was talking about the gear on the left is a tight fit in the block on the end of the TT. The gear on the right has the bearings on the shaft and rides on the anti rotation gear. The gear on the left fits in two bearings in the end of the TT. They are the same has mine. Only smaller. Your right you can't press new gears on the shaft on the right. It's a unit allready put together. I think we are just crossing signals and we are talking about the same thing! Lol

 

[Tony]

Oh yeah I know you and I are talking about the same thing. The ONLY time I have ever had to do any "press fitting" was when I had my HK250gt (Nightmare) and I ordered the Align tail gear. I found out later that I needed to order the block as the one that I did the press fit on failed ending in a crash when I lost tail control. If it's a press fit, you will purchase it already put together.

 

[breeze400]

I hear you on mine I have to pry the gear out of the block on the end of the TT. Then I start the new gear in the bearing and use the wooden vice on the end of my work bench and press it in the rest of the way. At the field I use a block of wood and a hammer to do it. But that may be just the way the 600 is. The last 1/4" or so is the hardest to get in all the way.

 

[Tony]

if you are talking about the TT rod into the front or rear gear, then tight is good. On my 450 it wasn't tight and just slipped right on. However with the very minimal play that was in it I did not see any adverse effects from it. Maybe I will have to get the 600 Pro to see what you are talking about

 

[breeze400]

Now that's a great idea! Lol

 

[Tony]

Only if you pay for it Mr. Money Bags lmao

 

[Bruno]

The part I reference is identified in the Align manualas the Torque tube drive. It is what tony posted as a jpg.

The Tarrot part I reference is Tarot T-REX 450 PRO V2 Drive Gear Set x2 | eBay on ebay. ebay item#: 130688324785.

I have posted a pic of the serated parts. Seems you can press the gear seen in Tarrot link above onto the shaft. I am aware that placement is crucial.

Regarding the glue/CA/epoxy there is some type of adhesive used with the assembly.


I just received the Tarror part in the mail. I got a completet assembly as well. I just thought I would experiement with the Tarrot part. I'll let you know what I may learn.