General Trex 450L - Learning to Fly - Stripping Tail Boom Mount Umbrella gear

[ilikeplanes]

Hi, finally got my Heli all setup and ready to fly (many thanks to this very forum).

Now as I learn to fly on two sorties I have stripped the umbrella gear inside the Tail Boom Mount.

Someone told me they believe it's due to hard landings. I want to confirm if that is what would cause this? Admittedly I have landed a little hard but none of the landings seemed that aggressive as to cause a gear to strip.

Also is the a common part to strip when learning to fly?

Thanks,

 

[Slobberdog]

I have broke one since I started with my 450 in June and that was caused by the tail blades catching on some longer grass, I have heard they will strip on hard landings but not sure what people class as hard,

 

[Derek]

Yeah, there are definitely different variations of "hard landings". Are we classifying "hard" as in scratching the skids or are we classifying "hard" as in smashing down to Mother Earth with full negative collective? I can imagine that a "firm" landing would probably not damage the umbrella gears but if your tail blades smack some form of resistance (dirt, cement, etc), you are most likely going to strip at least 1 tooth on that gear. It's because of that very reason that I opted for a belt drive tail for my first CCPM helicopter. I've have a few "not so graceful" landings (nothing broke, but not so graceful, lol) and the tail blades hit the ground and the only damage was the tail blades. Most likely because the belt will slip on the pulleys.

But, since you have the torque tube version...I would just recommend being certain that the rebuild is snug and correct, and then just try to avoid any tail blade/ground meetings. Something else to possibly consider is getting the black umbrella gears. I hear that the newer black gears are made from a more durable material. I don't have any installed on my torque tube heli's, so I have no voice of comparison, but that is what I hear.

I hope you get it figured out!!

 

[murankar]

If you fly the white gears you'll learn that a sneeze will strip them out. Unless you land almost nose first there is a high chance of stripping them.

I recommend that you go with the black gears if they are a available.

Sent from my LG-E980 using Forum Runner

 

[cml001]

My first flight w my 450 I strip'd mine w a firm landing in some thick grass... Also on a harsh landing once as well. U r fly'n the dominator? Does that model have the white gears or black?... While ensuring proper gear mesh is most important... And not landing w too much muscle... I also replaced all the white gears on my 450pro dfc w the newer black ones. They are suppose to be a bit tougher... And so far I believe so... I do use just a dab of "boto" lube on my gears as well.. I think the white gears had a self lube feature... But the black one did not... Check out the black gears if ur having to order... But I mean honestly.. It's more about not smack'n or drag'g the ground... And proper installation... Gear mesh is very important I have found.

 

[ilikeplanes]

I am flying the dominator and it has the black gears. The tail rotor has clipped grass or the dirt so I figure that is the cause.

But the tail rotor seems very close to the ground, only a couple of mm shorter than the tail skid. Is that normal? Is it possible to increase the tail boom length or run shorter tail blades?

 

[Tony]

You need to check your gear mesh on the tail if you are stripping out teh black gears. They are quite strong, but if the mesh is too loose, a rough landing will strip them out because the tail bends down thus opening up the mesh even more. You should have very little play in the gears when checking them. Just like checking the gear mesh on a motor.

 

[ilikeplanes]

Those gears sit in a magnetic enclosure and the gears basically lie inside that enclose and it snaps shut with magnets. I am not clear how to adjust the mesh on these gears. Any reference to a guide for the 450L dom?

 

[breeze400]

You'll probubly néed taller landing gears! I use 700 gear on my 600 cause of that!

 

[cml001]

Hummm.. I've not seen a dominator up close yet... Magnets u say?

 

[Mda1701d]

Hummm.. I've not seen a dominator up close yet... Magnets u say?

I know this is an older post, but I'm replying here as I am having the same trouble.
Not been able to get properly airborne yet, after a couple of tries. It seems the amount of tourque going through this heli on spool up causes all sorts of issues, the heli tries to tip to the left, so I compensate with a little right cyclic, then the tourque bends the tail boom so much it strips the gears. I'm trying to take off on grass, maybe concrete would be better. The tail rotors dig into the grass as there is so little clearence. I have seen pics of a short extension to the tail fin, might try that as well.

 

[Graham Lawrie]

I have had my gears strip on relatively soft landings I thought but it was bringing the throttle down quick and grass landing.

 

[Mda1701d]

Hello Graham,
I think mine is down to the tail fin being too low, as it twists the blades hit the grass, and strip!! I have seen a few pics on the net of mods inc a small piece of carbon fibre added on to extend the tail. I'm going to try this. It would bring the tail to the same level as the skids. Also, the next attempt at flight I will try on concrete! Cheers, Mark

 

[murankar]

I have seen people put a practice golf ball on there or a coat hanger. I did try the coat hanger once and it seemed to work. I secured it with a light zip tie in case of a hard landing.

Sent from my LG-E980 using Forum Runner

 

[Dirk]

I know this is an older post, but I'm replying here as I am having the same trouble.
Not been able to get properly airborne yet, after a couple of tries. It seems the amount of tourque going through this heli on spool up causes all sorts of issues, the heli tries to tip to the left, so I compensate with a little right cyclic, then the tourque bends the tail boom so much it strips the gears. I'm trying to take off on grass, maybe concrete would be better. The tail rotors dig into the grass as there is so little clearence. I have seen pics of a short extension to the tail fin, might try that as well.

I don't know your setup, but do you have softstart enabled on your esc? I does not sound like you do seeing that the heli goes commando on start-up.

One more thing. You should never try and compensate for roll while the heli is on the ground. The secret with FBL helis is to lift of positively and then compensate, but you will probably find that it will be unnecessary.

Keep in mind that no amount of cyclic applied to prevent a roll over while on the ground will stop the roll over. The ONLY way to stop roll over is to dump the collective pitch, ie, go to negative.

 

[Mda1701d]

Hi Dirk,
Yes, soft strt on. Tried spooling on harder surface tonight, but still ended in disaster.
Just stared a new thread on it. Perhaps you have some thoughts??

 

[Dirk]

Hi Mda,

Strange. How tight are your main blades in the grips? Are they both equally tight? If they are too loose or if only one is loose, I imagine something like that will happen. I run my blades on my 450 and 550 relatively tight in the grips. It prevents one blade "lagging" behind when I spool up.

Edit: I just replied to your other post you made.

 

[Graham Lawrie]

Hi Mark, I have had multiple flights on my 450 and never had to extend the tail. I have seen a few that have, but I have found it difficult in grass. I always worry that I will cause more damage on concrete

 

[krash]

i hav a 450l,thats normal,it may help to loosen the boom brace and push it up a bit and tighten th brace whilst appying slight upward pressure

 

[Graham Lawrie]

The other thing I have noticed about the 450 is until it spools up above mid stick it can be twitchy I have found with a bit of confidence to be more (fast and quicker are the wrong words), but more positive with lift off, almost like get her off the ground