Eflite CNC Lower Hub
 

I must be charmed or I'm onto something here! As some of you may have read I flew my heli into my arm last night fighting wind. It was enough of a hit that it broke one of my lower blades and dusted my tailboom. However that's not the real story. I was flying tonight and my controls were all over the place, aileron right or left would produce forward flight....very very strange things. Upon further investigation my lower hub was twisted....yes twisted. The lower hub extensions that keep the swash linkage to the lower blades straight were on a severe angle. I can literally twist the linkage in either direction, it is snug however it still moves. I straightened it out and flew for one whole bat no problems didn't move under normal flight conditions. So just for fun :) I purposely did a blade strike! Yeah I know...come on guys this is me....I've done dumber things with this bird :) Didn't break a blade but did twist the lower hub. Straightened her back out...flew no problems through normal flight. So what have I stumbled across here? Are they supposed to do this or did I have two bad lower hubs? Wish I had another new one to test out. Anyone else have this occur?

RE: Eflite CNC Lower Hub
 

Mine's still a solid chunk. [:o]

RE: Eflite CNC Lower Hub
 

Stump3r,

I have a working lower in my hands now. I think You have a coat hanger affect going on, they are getting weaker with every strike and the next strike may break them clean off, if You are talking about the extension arms themselves. If You are talking about the entire lower rotating, then You either don't have set screws holding them or they are loose. You might be onto something, I'm not sure at this point. I'm sorry, I'm tired, tonight.

Am I right?

How's that arm, anyways?


Gary

RE: Eflite CNC Lower Hub
 

Do you have the E-Flite CNC lower?
Isn't that two seperate peices?

RE: Eflite CNC Lower Hub
 

Well lets leave this until tomorrow so I can get some shots of it. Left my digi cam at work. All the allen screws are set and loctite has a grip on them :) Will investigate further and report!

RE: Eflite CNC Lower Hub
 

Yes, I do.

RE: Eflite CNC Lower Hub
 

My e flite lower head is two peice and you have to algin it when you install it.

RE: Eflite CNC Lower Hub
 

Okay here are some pics! Sorry for the quality it's with the wifes digicam that isn't the best.
The first picture shows the twister :) Both upper and lower sections of the hub are secured properly.
[img]http://www.rcuniverse.com/forum/forceddownload.asp?file=0;6535668
IMGP0352.jpg[/img]
The second shot shows how the upper hub is separating or rotating on the blade hub upper side.
You can see how the rounded part of the hub has raised edges that should align with the flat of the hub notice how it's twisted over. This is the same as the first one I destroyed. [img]http://www.rcuniverse.com/forum/forceddownload.asp?file=1;6535668
IMGP0351.jpg[/img]

RE: Eflite CNC Lower Hub
 

Also guys, if ya want to see how one gentleman went brushless, here is the link here to the pic, and how he explains on how he did it...He's actually been on-line here this evening....It's a link to RCU here in another thread from awhile back...Go to post #5....Alright, take care guys, and keep dreaming...Lol....! Where there's a will....There's a way...................Jeff

http://www.rcuniverse.com/forum/m_53...tm.htm#6403616


Edit: OOPS...! meant to put this post on the other thread that you guys were discussing...Lol... "Building the ultimate CX2"...Either way, you'll see it, as I saw ya guys talking about it..Have fun.........! Jeff

RE: Eflite CNC Lower Hub
 

After thinking about this for awhile the break is a good thing. Looking at the MH cnc hub it's solid as a brick, with a smack hard enough to twist the eflite hub, for sure the MH one would have taken out the outer shaft, then again an outer shaft is alot cheaper than a cnc lower hub.
Stump goto bed your tired!

RE: Eflite CNC Lower Hub
 

Again, if this is the E-Flite lower then it is two pieces that can easily twist out of alignment.
Also, it does not look like the upper set screws could possibly be in the holes on the outer shaft because they are not screwed in far enough.

So if it is the two piecer then I can see how the upper part of the head is twisting.
If the picture is of the MH lower head then I have no idea what happened.

Am I missing something?


EDIT: It didn't register that the title here is "E-Flite" CNC Lower Hub.
So, I stand by my analysis that the two upper set screws are not in the shaft holes and/or the lower set screws are not tight enough.

RE: Eflite CNC Lower Hub
 

yeah, i agree - the upper set screws didn't get into the shaft holes - the lower screws are only there to help vertically center the hub on the shaft so they don't have shaft holes to go into, but the upper screws must be in the shaft holes or you will get twist, or worse, sliding up and down! - on the one-piece hub you can fly without the lower screws, but the upper ones are mandatory, and they gotta be in the shaft holes - same with the stock lower hub


edge

RE: Eflite CNC Lower Hub
 

I've had this happen to me. You need to remove all 4 allen screws and re-align the two pieces of the lower head. I do this with a paper clip. First, I align the upper portion with the holes on the outer shaft. Then, I stick a paper clip all the way through the outer shaft. Obviously, you need to have the inner shaft removed for this to work. Once the upper head is held in place by the paper clip (A large, thicker one), I align the lower portion to teh upper portion and secure with allen screws. Once that is locked in, you're free to install the upper portion screws quite easily.

RE: Eflite CNC Lower Hub
 

Jeff;

Thanks for the info. . . again; iIbookmarked it this time.

Gary

RE: Eflite CNC Lower Hub
 

Wolf, CX and Bry. The set screws are set correctly! Trust me :) They are in the holes and set deep enough. The Eflite upper hub is actually three pieces. You have the upper section with the blade lugs and set screws, then you have the lower section with the guide rods for the swash linkage and lower set screws.
Third section what third section?? Stump is on crack again!
If you look very closely at the upper piece of the hub it is actually two pieces. The rounded bottom section that has the blade lugs and this piece is compressed onto the upper section that has the set screw holes. What has happened with mine is the section with the blade lugs rotates on the section with the set screws.
When set properly on the outer shaft the upper set screws, the blade lugs and the lower set screws align one above each other with the guide legs for the swash linkage being at a 90 degree angle. Have a look at the second picture above again. You will see that the upper and lower set screws are still aligned correctly however the blade lugs are at roughly a 30 degree angle.
This is the second hub I have had separate at the same location. Unfortunately I threw out the first one. I should have kept it and taken pictures of it. When I replace this one I will shoot some pics and post them to further illustrate what is happening.
I'm still wondering if this is manufactured this way or did I get two bad hubs.

Found a picture, here is a side preview of the eflite lower hub. Note how the blade lugs and set screws align, now look at the second picture. See how the blade lugs have twisted off line with the set screw. And you guys thought I was on crack :)

RE: Eflite CNC Lower Hub
 

stump,

OK, I'll buy that explanation. I don't have that part so I wasn't sure.
Get the MicroHeli lower head, it's all one piece. Mine has worked great so far...only a few flights.
And it is lighter than E-flite's.

HopMeUp on ebay has the part for about $9 plus shipping. It comes in blue or silver. I've had excellent results with this seller.
I also have their phone number if you want to call them about shipping to Canada, PM me.

You could always use something like JB Weld to stick them together.

RE: Eflite CNC Lower Hub
 

Didn't know that stump3r. You learn something new every day!

I have been running the E-Flite aluminum lower head on my new CX2 for several months. I just installed one on my old CX2 as well. No problems. The one time where I saw what you have right now is when the lower set screws came loose and the lower portion rotated. I was able to fix it.

RE: Eflite CNC Lower Hub
 

I'm still shocked over how little of a hit it took to rotate it! I'm thinking of emailing horizon however typical manufacturer would claim abuse and not send anything anyway :)

RE: Eflite CNC Lower Hub
 

You are not imagining things. My E-flight lower head failed exactly the way you discribed. I was wondering if I had the only one doing that. I wonder how many more out there are having the same problem?

RE: Eflite CNC Lower Hub
 

When did you buy that, stump3r? How long ago? What about you, wxup?

RE: Eflite CNC Lower Hub
 

Last Saturday to be exact. Same LHS I bought the last one from. However judging by the picture I grabbed off the net I would say they are all built the same way. If so I would say all prone to the same failure. Personally I think I'm going to try the MH version and see if it's any better. I would rather take out an 8 dollar shaft than a 22 dollar hub any day of the week. I already chatted with my LHS and they won't do anything with it. I just might drop a line to Horizon and see what they have to say.

RE: Eflite CNC Lower Hub
 

I got mine a few months ago. I am thinking about putting a drop of superglue on it to see if that holds it in place. If not I am going to replace it with the MicroHeli one.

RE: Eflite CNC Lower Hub
 

Oh, yea, Superglue works real good; trust Me ;)

RE: Eflite CNC Lower Hub
 

I gotta try the superglue....I'm tired of these things separating!

RE: Eflite CNC Lower Hub
 

stump3r, I have the same situation happen to me, and the screw wer all set right. I even tried to push it downwards and it separated. I end pusshing ot back up after applying superglue and it works fine afterwards, just make sure you align it well before the glue sets.