emosolo

Hi Guys,

I am building a 450 Pro shaft tail driven version. I have a problem with the umbrella gears right at the back of the tail. The umbrella gears are binding. I have removed the rear assembly and the gears in the front driven by the auto-rotation gear run free, however when I re-assemble the tail, again I have binding. Being gear driven I would have expected there to be a very small degree of lash, however there is none.

Should I remove a very small bit of material from the base of the umbrella gear that goes into the tail shaft, therefor allowing the bearing to sit slightly lower giving me that little bit of lash I was expecting, or is there some other trick common to this heli which will resolve the problem?

Secondly, do these gears need to be lubricated or the fact that they are Nylon in itself being sufficient lubrication.

Finally, the main gear seems not to run completely true which creates horrible vibration even when the head assembly is fully removed. I have replaced the main gear already hoping gor better results (Making sure not to overtightren the bearing plate assembly) and still no luck. Is there some way to ensure a true and straight running main gear?

Regards,
Solo.

Rob2160

Hi,

Is it a clone 450 Pro? I have two of the Hobbyking versions.. Both of my tail gears mesh ok with no binding..

Iuse a small amount of labelle 107 oil (which is plastic safe) on all the gears.

The main gears on the clones are notorious for not running true.. I usually replace it with a genuine Align main gear which will run much smoother.

emosolo

Hi,

I have replaced the main gear with an Align genuine part and find that it is still not running true. Anybody else got any ideas on the original post?

Regards,
James

emosolo

Morning.

I have resolved my tail shaft binding issue. It was a misformed umbrella gear that was not running true. Still trying to find out how to get a true main gear however. I must say, I did notice this issue on my V2 as well when Align upgrade the main gears to have the removeable one way bearing bit. The old main gears used to work perfect.

Seems silly that I, if I cannot find a solution will have to have a vibrating heli because of shoddy parts from Align. Is Align perhaps slipping in quality?

Anyway, enough ranting, if any of you have a plan to give me a true running main gear, I would be very appreciative.

Regards,
Solo.

ehernan3

I have a Sport version(belt driven tail), and I can't recall how similar the main gear is, but here is what I noticed: the motor drives the main gear, which also drives the gear that drives my tail. The tail driving gear is held to the main with four small screws and metal plate.

When I was replacing my main gear, I had to ensure the two gears were pressed together fully; simply tightening the screws to the plate is no enough. If I don't do that, the tail driving gear is mounted at a slight angle relative to the main gear, and produces vibration(and appears visibly imbalanced).

Like you, I noticed this when the head was removed, and I was surprised how much vibration occurred without any blades or paddles or linkage installed. But once I realized what was happening, and solved it, the vibration disappears without changing any parts.

Hope that helps, even with a shaft driven tail.

Ed

emosolo

Morning,

So with regards to the main gear. I did the microwave method. I heated the the main gear in 5sec intervals until the gear became slightly soft(about 30secs total). I put the gear face down on a mirror(Perfectly flat surface) and then put a mirror ontop of the main gear. I added extra weight to force the gear 100% straight. It only took about 2 mins to cool down to regular temp. I re-added the metal hub, being very careful not to overtighten the hub screws and did so in a x formation pattern. The gear now runs with about 0.3mm wobble, very very little.

Of course now I have an issue with the tail rotor gear. The one that sits below the main gear. It doesnt run true. The problem is that the one way bearing will typically give way vertically in one direction(not talking about the functionality of the bearing), so if you push up on the gear on the side that is down, the gear becomes mis-aligned in the other directions. To help resolve this i very carefully adjusted the gap between the main gear and the tail rotor gear as I hand turned the main rotor. This will probably go out of alignment during flight because there is not equal pressure being delivered to the hub inside the tail rotor gear from the oneway bearing and will always tend to give way a little more on one side. Design flaw i believe after watching many vids on youtube. Not on any of the choppers that I watched did the gear run true. This is of course unfortunate as it causes an inherent vibration that you will never be able to resolve. I really do hope that Align change the design to resolve this. The only thing I could think of was to remove the one way bearing(Yes giving up the chances of an auto in failure(not worth the risk)) and replace it with a custom aluminum ring that the tail rotor gear hub would then be permantly fixed to. I chose to keep the one way bearing and have a slightly mis aligned tail rotor gear.

In addition to this I noticed that I had a very slight binding of the tail pitch slider. This came from where the tail rotor grips screw into the tail pitch slider arms. The screws were making contact with plastic arms and not seating directly onto the brass collars. I removed an extremely small amount of material from the plastic arms allowing the screws to sit directing against the collar and therefore not touching the plastic. Simple fix to resolve a potentially dangerous binding issue. Although the binding was minimal, I have experienced tail rotor failure before on my Raptor 50 and when you are inverted 3M of the deck, there is very little chance of recovery.

The only other problem I have had with this kit are some of the bearings in the already put together parts like the pitch arms on the main rotor head. In the very few places that Align did put threadlock on, thread lock was put on the bearing creating unsmooth movement in the parts. Although there is very little resistance when you move the part by hand, I take into account that when the rotor is turning, the pressure on these parts is increased exponetially and therefore any form of binding could become a failure or increased wear on the bearings could turn into a seized bearing. I have not as yet had the luck of a seized bearing yet so I am still waiting for my turn.

Positive things about his kit. I would say I was very impressed with the newly engineered frame and basic mechanics. I love the way they have the servos mounted in the 450 pro, it is much better than before. The biggest advantage is that all the servos are installed at the same height and so all the servo linkages to the swashplate are exactly the length. I also prefer the new tail servo mount, although it doesnt allow you to change its position, its sits and hides itself nice an tidy in the back of the frame. So instead of moving the entire servo to get the travel on the tail slider even, you now have to adjust the linkage. I think moving the servo was easier, but I can live with the tail linkage length change for the tidyness of tail servo. Another small change that is a plus for me is the way they have now mounted swashplate stopper. Thicker more sturdy material and mounted in such a way that it cannot move. The V2 swash stopper could be tilted backward and farward a bit. The new landskid system I am not sure about. I like the ease of a solid landing skid, but preferred the asthetics of the traditional landing gear. In terms of functionality I can not yet comment, I am still in the build phase. (About 4-5Hrs away from complete, but I have enjoyed this build so much that I have forced myself to only spend an hour or two every other evening to make it last as long as possible).

I am curious to find out how the Pro will compare to my 250 as I thought my 250 completely out performed my V2 in terms of stabilty and ease of flight. Also the power ratio was really good and all stick inputs extremely crisp.

I hope I have not dragged this post out, but would appriciate comments on your experiences etc.

Regards,
Solo.

Rob2160

It is a great helicopter..

Here are two vids of mine

What motor are you planning to use?

[youtube]http://www.youtube.com/watch?v=1kQ6nEPdvsc[/youtube]

[youtube]http://www.youtube.com/watch?v=5GxRFSPVknU[/youtube]

stoya789

they aren't called umbrella gears they're called beveled gears.