View Full Version : main gear shake

03-06-2011, 08:35 PM
is it possible that my main gear from my axe 400 3d has become warped and causing a vibration in my heli, i have rebuilt after a crash, main shaft was slightly bent as well as feathering shaft etc, and now i have a vibration that i can see mainly in the boom supports and tail fin, i have ballanced the head and all is well there but if i run the heli without the head the vibration is there, the only thing i can think of is the main gear, what do you think?

Blade Buyer
03-07-2011, 01:52 PM
Had a crash on mine the other day. Nothing major, just a roll near the ground. But to my surprise the main and feathering were both bent. If you have any doubt, replace them. There are some who have a way to straighten feathering shafts that are not to bad. If you search you can find the info.

Also check the frame for cracks. If you hit just right (or wrong in this case) or hard enough, the frame may take the hit and crack.

Good luck.

03-07-2011, 08:41 PM
hey, so i removed the head and only have the tail connected and wheni run it up the boom vibrates badly, i have changed the main gear and the main shaft but cannot find where the vibration is coming from, i'm thinking now that it might be in the tail area

Blade Buyer
03-07-2011, 08:59 PM
OK. I read your post again and agree that your problem may be in the tail. I am having tail issues with mine as well. I ordered a new drive shaft after a tail first crash. The old one looks OK but as long as I was getting parts, well you know how that goes.
Anyway, depending on the severity of your last crash, the tail could be the vibration culprit.
I do not know of any method to balance the tail except order a new shaft and install. Maybe there is a video or someone with the goods on servicing the Axe tail. It could help both of us.

Desert Fox
03-08-2011, 08:51 AM
If you think the problem is in the tail,
1. The belt. the crash could have ground out a spot or spots in the belt grooves?
2. The Tail Rotor Shaft. could be bent/ damaged teeth. causing the vibration?
3. The Tail Rotor Gear Case Assy cracked/damaged. allowing flexing of assy?
4. The Secondary Tail Belt Drive Gear w/pulley. damaged teeth ?

You can loosen the four screws in the frame for the boom mount. slide boom forward to release tension on belt. You can disasemble the tail rotor gear case assembly with out removing the boom.
Attached is a copy of the Align Trex- 450XL which has the same tail setup.

03-08-2011, 10:54 AM
hello, my vibration seems to be mainly in the boom, i have changed most of the tail bits just to see, i also disasembled the body and found one of the main bearings is gritty as well as the bottom one on the idler shaft, i have ordered them and will have to wait to see if that makes a difference,

Blade Buyer
03-08-2011, 12:37 PM
Guess your waiting on parts like I am. Ordered from RC Planet out of Utah.They said they would ship the next day but that didn't happen until 3 days later. A week later and still no parts. They had a great selection, just poor shipping. :thumbdown: Same with Hobby King.:thumbdown:
If you find a faster outfit that ships let me know. Or at least an honest one about their dates.

Thanks. I did not know those tails were interchangeable.That may make getting parts for the Axe a little easier. Cool.

03-08-2011, 03:20 PM
tower hobbies are very fast with teir shipping and i just ordered parts from hobby zone they had everything for the axe, 99% of trex 450 v2 stuff will fit the only thing that doesnt is the swash plate but all the head parts fit,and the tail, not sure about the maingears and idler gears, i have started to upgrade the head on mine and they are a direct replacement

Blade Buyer
03-08-2011, 05:20 PM
UPS guy came about an hour ago. The tail shaft came in a package of two. I may work on the bird later or over the next couple of days.

Thanks for the info about the Align crossover parts. I will have to do a slow upgrade on mine as well. And I have used Tower before with good results. RC Planet had the parts for my E-flite stuff, Heli-Max 400 for my friends Align 450. Just thought I had found a one stop shop (web-site) for parts.Oh well, the hunt goes on.

Desert Fox
03-08-2011, 06:28 PM
Blade Buyer,
ONE STOP SHOP! Never, bargins are all other the map.
E-flite = www.hopmeup.com (http://www.hopmeup.com) Good prices, fair shipping prices, fast service.
Align = www.helidirect.com (http://www.helidirect.com) fair prices, good shipping prices ( starting at $2.60), fast shipping
There are many others, depends on item.

Blade Buyer
03-08-2011, 11:56 PM
Thanks Desert Fox, I added those sites to my list and will give them a try. Thanks again.

03-11-2011, 09:36 AM
managed to get rid of my vibration, turned out to be the main bearings, i changed them last night, i ordered from hobby zone and it came within 2 days, and tried it this morning and its as good as its always been, the old bearings although there was no real play in them one of them felt very gritty so i'm assuming that it had broken down, anyway maybe this will be of help to someone with a similar problem

Blade Buyer
03-11-2011, 12:11 PM
Good job anthony1, My friend has the same vibration in his Trex 450. We will check those bearing as well based on your info. These sites are so cool for diagnostic info. :thumbup:

03-11-2011, 12:56 PM
glad to be of assistance

Blade Buyer
03-11-2011, 10:55 PM
Axe flies again. Had to move the tail servo into the correct position on the boom. Thanks for the help. Both of you.

03-15-2011, 08:16 AM
ok, i have finally given up with my axe and ordered a trex, i fixed the vibration using main bearings and tail drive gears, flew 2 times and the vibration is back worse than ever, the 2 parts i have just replaced have broken down, if i want to get them replaced under warranty i have to send the parts back to helimax with my receipt and they will replace them, all this will probably take 2 weeks, i have spent more time trying to fix the problems by upgrading the inferior parts with align parts and i have now had enough, so i have trex 450 head and tail assemblies that are a direct replacement for heli max parts for sale

Blade Buyer
03-15-2011, 05:19 PM
You could just keep the parts you have on hand for the 450 and have spares for your new bird. Or buy a CF frame with a shaft drive and input your tail and head parts into that project. May as well get use of what you have on hand.

03-15-2011, 08:31 PM
i did think about that, the parts i have are different to the sport version but might make a good project for my son, the axe flew really well i am just disappointed in the quality of the parts, if they could get that right i think they would be onto a winner

Blade Buyer
03-15-2011, 11:37 PM
Yeah I know,the all plastic thing can wear on you. I've been looking at an EXI for my next bird. It has a CF shaft drive frame with a CNC head and tail kit for about $85. Then add electronics. Maybe $300 tops. A lot of guy's give them :thumbup:.
Good luck with your 450. Let me know how the maiden goes.

03-18-2011, 08:29 PM
well i flew i today, twice both without incident, in fact i didn't need to adjust anything, even the tracking was spot on, i only hovered in my front garden but it still feels more solid than the axe, i'm not knocking the axe i still liked the way it flew,but my lhs doesn't carry parts for it and as i am still in the learning to nose in stage parts need to be available quickly, i have a furion 450 too and while i only hover that tail in (too scared to do anything else yet) this is a step up from the trex it is so stable and sounds like a sewing machine, good luck with your project, i have sent the bearings and idler shaft back to helimax for replacement so i may one day get it back in the air(or i might let my son have a go)

Blade Buyer
03-19-2011, 12:19 PM
I have a CP Pro 2,SR,and Axe 400. My latest addition to the inventory was a msr to fly indoors and bug the wife. Debating on whether to build the EXI or order a mCPx (flybarless) from HH as the next "victim".
Surprisingly my nose in skills are pretty good. I think the simulator with a real heavy bird
( a Huey canopy model) helped that. It might help you. Seems like after a while the reactions (while flying nose in) just come naturally.

03-19-2011, 07:29 PM
i have to admit that nose in isn't too bad ,its getting to it that was the problem, flying in my front garden i have a few trees and space is small so i have to piro to get nose in, what i forgot is that the heli doesn't hover straight but one skid low and when you piro you have to correct for this, took me a while to figure out , but now i think i am there, flew 8 times today mostly side on and stopping at the four points,its fine with the training gear on but definately a higher pucker factor without, i have done it but i am a bit nervous, so i want to get completely comfortable with all orientations before loosing the trainers, i did take a video this aftrernoon but dont know how to upload it yet
as far as the sim goes i can do all orientations with no problem with the axe even inverted but real life is different, i know i can do it but my wallet says NO, i flew planks for many years and i think that helped a lot too, my picture was taken nearly ten years ago in my back garden in england, we moved here 8 years ago and i haven't flown again until now, i guess the bug never really goes away

Blade Buyer
03-19-2011, 11:23 PM
I can relate. You get out there and the "If I crash it's going to cost me bucks" factor starts raising it's ugly head. One thing I have found that helps a lot is to check "profile" constantly. Meaning, make sure over and over that the present and future attitude of the heli is correct and manageable. Bottom line is, do not take your eyes off of the heli and plan ahead for it's orientation. And if your like me you will develop a knack (most of the time) for the "save",where if it gets goofy you can catch it before a crash. Like I said "most of the time". I still do repairs, just less often.