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A Main Hobbies . Boca Bearings . Modefo's RC Helicopters

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e-Century Hummingbird - Swift > Incorrect disk movement
 
 
brian_christie
Senior Heliman
Location: Riverside, CA

OK.
I noticed this before I did the "tube mod" (seems to have more power now!). Gave full power and moved the cyclic controls...

It seem the rotor disk isn't moving correctly. All of the linkages seem to be connected correctly.

If I move cyclic forward and reverse, the disk moves forward and a little to the right/rearward and to the left. Same for right/left...seems to move a little fore/aft. Almost as if it's going diagonal.

Any ideas on what I should do / check?

Thanks!
07-12-2003 Over year old.
HOMEPAGE  
 
 
Ross R
Veteran
Location: Rochester NY

The tube is probably binding somewhere. Check that first.
07-12-2003 Over year old.
 
 
Gazoo
Veteran
Location: Maryland

You will probably need to adjust the trims on your transmitter.
07-13-2003 Over year old.
 
 
brian_christie
Senior Heliman
Location: Riverside, CA

Nope...not the trims...

OK.
What I found with the collar modification....

The swash has a little too much play on the inside diameter which allows the swach to clode to the forward / right side. This causes cyclic controls to function more like an X than a +.
Forward becomes forward & a little right, aft becomes anft and a little left.

I'm sure one of the new swashplate upgrades would fix this, but I have no funds at this time for that so...

Back in goes the "black tube". Grrr.

I think I will just put a small piece in to satisfy the spacing requirements for the swach. Kind of like a "hybrid collar/tube" upgrade. (would that be a "midgrade"?)
07-13-2003 Over year old.
HOMEPAGE  
 
 
Gazoo
Veteran
Location: Maryland

Thanks for the information. I am still putzing around in my kitchen, but will keep this in mind.

"I think I will just put a small piece in to satisfy the spacing requirements for the swach. Kind of like a "hybrid collar/tube" upgrade. (would that be a "midgrade"?)"

Midgrade...I like that

Someone else posted that they had done the same thing. I saved my tube just in case, and now I am glad I did. I think it is a good idea to cut the tube, and leave the collar on as you suggested. I don't know if the aluminum swashplate would solve the problem, but I would think so.
07-13-2003 Over year old.
 
 
parkguy
Senior Heliman
Location: San Diego CA

take the tube out

the whole reason for removing the tube is that it causes drag first off taking it out lets the plate move around free make a world of difference all you have to do is add the coller to keep the main shaft from sliding up and down and the HB flys so much more stable.. trust me when you can hover for 5 minutes at a time in the space of the tobe of your kitchen table then you will see what i mean. you also wont overwork the motor ( burn out the stock one's)
07-14-2003 Over year old.
HOMEPAGE  
 
 
bjames
Heliman
Location: Singapore

still happen even after undo the mod

Hi,

I have exactly the same problem after applying the shaft-collar mod but the problem is worse than brian's - the cyclic control seems to be rotated 90 degree clockwise (eg forward elevator would be come right aileron, left aileron would become forward elevator etc).

I've undo the collar mod and put the plastic tube back but the problem still happens !!!

All servo arms movements are confirmed to be correct. I've tested to throttle up w/o the main blades and watch the flybar disk movement, the same tendency is still there though the discrepancy is smaller.

Any idea? I'm reading this and thought it may have something to do with the strange behaviour, however I can't make any sense of it.

The HB is now parked until this condition is solved
07-14-2003 Over year old.
HOMEPAGE  
 
 
parkguy
Senior Heliman
Location: San Diego CA

question

do you have a picture or pictures of yor HB that you can send me..
07-14-2003 Over year old.
HOMEPAGE  
 
 
bjames
Heliman
Location: Singapore

I wish I do, but I can't today,
not until I borrow someone's camera or until I buy to replace my stolen one
07-14-2003 Over year old.
HOMEPAGE  
 
 
brian_christie
Senior Heliman
Location: Riverside, CA

Redo...

OK,
Tonight I will redo my collar installation. I may have had too much of the black tube as a spacer and caused the collar to rub on the swash.
I'll attempt to post pics tonight.

BC
07-14-2003 Over year old.
HOMEPAGE  
 
 
Gazoo
Veteran
Location: Maryland

bjames,
This is the first I have heard of anyone having a problem like yours, to the severity you are describing. If you notice on the swashplate, two of the arms are a little bit longer. Last night, I tried connecting the linkages to the longer two arms and found that I could not control the heli as easily. This may be the reason why you are experiencing the problem. The other thing that can cause it is if the heli is too tail heavy. I do believe that the heli should fly fine with the tube completely removed.

The only other thing I can think of to do is to compare your swashplate area to the picture that is on parkguy's website to make sure you hooked up the linkages properly. Link follows:

http://www.electricmicro.com/upgrades.html
07-14-2003 Over year old.
 
 
Gazoo
Veteran
Location: Maryland

I just had another thought. The servo tape that comes with the heli is not the best. I am using 3M tape. Some people have used hot melt to reinforce the servos. Don't know if this will help, but I wanted to post before I forget...LoL
07-14-2003 Over year old.
 
 
bjames
Heliman
Location: Singapore

Thanks Gazoo, parkguy.

I don't believe it myself until it happened to me. I thought that this is the kind of problem a flybar is supposed to fix, and my other HB flying buddies who did the same mod does not even have a problem at all !

Anyway, I checked parkguy's picture. Everything is in check, I swapped the connection from the short one to long one then to short one again. No difference.Tail is OK, when I hang the heli on the flybar, it's quite balanced.

Ok, I have not check on the servo tape. I have temporarily passed my HB to a friend with more experience, he would help me to look into it. TIme to cross my fingers

I'll keep the rest of the forum updated, whether the problem can be solved or not.
07-15-2003 Over year old.
HOMEPAGE  
 
 
parkguy
Senior Heliman
Location: San Diego CA

No problem

Keep us informed on whats going on..
07-15-2003 Over year old.
HOMEPAGE  
 
 
brian_christie
Senior Heliman
Location: Riverside, CA

What I found last night...

OK. I put the collar back on with a *really tiny* piece of tube as a spacer. I got a bad vibration in the head as it spooled up but at hovering speed all was OK. It would always shake bad during the transition through a certian head speed.

So I just held it and seemed to be OK. Looked like some occilation was being induced by the training gear. I then gave full power and tilted the swash to its extreme throws...the swash was binding on the collar ever so slightly causing some *wild* shaking as well as that fore/right and aft/left condition. The servos are mounted rock solid.

Bottom line: the swash hitting the collar caused my fore/right and aft/left condition.


I guess I'll have to break down and buy that *real* collar mod for this puppy. Until then...I'll be "black tubin' " it.

BC
07-16-2003 Over year old.
HOMEPAGE  
 
 
flyboy
Elite Veteran
Location: California

Huge differance.

I am not following your problem. I simply replaced the "black tube" with a flybar weight and the improved perfpormance is amazing.

More power, the hummer now jumps into the air, less drag on the main drive, and considerable improvement in cyclic response.

I couldn't ever fly one again with out taking the three minuets to make the improvements. Such a large difference in performance, the time it takes to make the modification is justified by gaining almost as much time as the upgrade took, in longer more responsive flights.

Pictures to follow shortly.

Email or PM with any questions.
The new tape that comes with the kits is 3M I believe.
Poor picture, but you should get the idea. Check linkages.
07-16-2003 Over year old.
 
 
parkguy
Senior Heliman
Location: San Diego CA

training gear.

Brian

wow stupid me the training gear for the hummingbird is where the trouble is the vibration is caused from the air hitting the balls and making them move up and down, trytakin the balls of the rods that will fix it. I never used the traing gear but had a friend who never had flown use them and it really made it wobble..
07-16-2003 Over year old.
HOMEPAGE  
 
 
flyboy
Elite Veteran
Location: California

I just set up one for a friend. I put the training gear on it for him(first helicopter) and spent a few minuets balancing the blades(static) and making sure the tension was the same on both.

I had a slight resonance at certain times, but nothing more than an eighth of an inch at worst. I thought that the little thing would never fly with the added weight, it didn't seem to bother the performance at all.
I would strongly recoment them to beginers.
07-16-2003 Over year old.
 
 
brian_christie
Senior Heliman
Location: Riverside, CA

Flyboy,
Did you use one of the "modified" collars? The one with the little "lip" on the bottom, or did you just use a regular collar and no spacer under it?

All of my linkages look just like that picture. Do you have any odd disk movement?


ParkGuy, with the tube on, there is no shaking. Tube off, collar & spacer on it shook.

I'll try using just the collar tonight and see what happens. (Wish I could play at work!)

Thanks for the info and help, guys. I'll get this darn tube evicted yet!
07-16-2003 Over year old.
HOMEPAGE  
 
 
flyboy
Elite Veteran
Location: California

Just a plain collar. Don't need any spacer just leave about a (papers thickness) space between the collar and plastic bearing collar. Just enough to see light through the space. Make sure not to over tighten set screw. Confirm collar is 90 degrees to main axle. Spin and see that it doesn't wobble and rub plastic. A drop of triflow, just to keep it smooth.

I am no rocket/physics scientist but I believe the collar is simply to keep the main mast from sliding out, the helicopter hangs from the main axle so the washer spacer that you mentioned is not needed.
07-16-2003 Over year old.
 
 
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e-Century Hummingbird - Swift > Incorrect disk movement
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