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06-16-2013 11:57 PM  5 years agoPost 1
cueman100

rrApprentice

Santa Clarita Ca. USA

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when in a hover I notice the my skids have a vibration Im wondering if it could be caused by the blade grips on the head pictured below. if you notice there is a bolt that holds the blade grip on the head. There is no way to know if you have them perfectly straight except to eyeball them before locking them down. if they are slightly off, would that cause vibration? the blades are slightly loose so that they will straighten out during spool up. If I leave the grips slightly loose too then the heli shakes very bad like it want to explode during spool up until everything straightens out. what would you guys suggest I do.
Thanks

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06-17-2013 12:30 AM  5 years agoPost 2
coptercptn

rrElite Veteran

Mesa AZ. USA

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one method would be to spool up and hit throttle hold. let the head spool to a stop and carefully tighten each grip. leave the blades slightly loose and spool back up. check.

personally.. I would look for a better head..?

Home of the "Sea Cobra".....

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06-17-2013 01:33 AM  5 years agoPost 3
Mojave

rrElite Veteran

Palos Verdes, Ca. USA

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I agree with the Capt., and I have never liked that head design. There should be a machined flat for the outer section to register to the main spindle section. If you don't want to replace the head, a good machinist could index it, then drill/pin the grip part to main spindle section. Or, you can find a feeler gauge that fits in the gap and use it to hold the grip in the correct position while you tighten the bolt. If you look at the starwood Lama heads, there are 2 bolts that retain that piece and hold the alignment.
Barry

All helis and planes have an expiration date stamped on them...you only find it after you crash!!

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06-17-2013 02:09 AM  5 years agoPost 4
doorman

rrProfessor

Sherwood, Arkansas

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+1+1^^
I have to agree with both of the above posts...
I don't think I have ever seen one built like this, but I can fully see how it could be causing your vibe problems...what you are witnessing is a "lead/lag" problem and with the way that grip is attached it will just exaggerate the problems even more...
I am going along with a possible head replacement if possible.. or as Mojave suggested get a good machinist to put some flats on the grips so that they do stay aligned at all times...
Also the blades should be run with some drag on them.. Not too tight so that they cannot "throw out" to straight, and not so loose so that they move too easily..

Good Luck and let us know what you choose to do and how it works out...
Stan

AMA 2918-Team Spin Blades,,Castle Creations, Unique Aircraft

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06-17-2013 09:01 AM  5 years agoPost 5
PETER ROB

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Devon UK

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There is no way to know if you have them perfectly straight
Not true
Switch on transmitter, and receiver, ( set mid stick, but zero pitch is best)
If you remove the control rod from the blade grip
Move the blade (balances) until the ball on the blade grip lines up with the control rod
Tighten up the grip (not too tight)
Check that the balls line up with the control rod and pop them back on
They are now all the same

Len Mount used this method on his 2 bolt blade/grips, the lagging hole he used to file so that he had some play, using the method above he would then clamp his blades tight

Do not know about that head, but sounds like you need to do some balancing
Peter R

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06-17-2013 01:26 PM  5 years agoPost 6
modtron

rrKey Veteran

Oxford. UK

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I run the same head on one of my 90 machines without any problems - but I did make a jig to line up each axle and bland holder first to get them all in line and the same before locking them up tight.
Then, as they others all say - fit your blades with just a little friction movement and all should be good to go.

I don't use the swashplate as its a bit crappy - changed it out for a Vario item and swash driver with normal pushrods.

modtron
Oxford UK

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06-17-2013 01:57 PM  5 years agoPost 7
Young

rrNovice

China

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I agree with above post.
Please balance blades first. Unbalanced blades will cause vibrations.
And then don't tighten the blade too hard. It should be tighten until can't be move by hand easily but still can be move.

If you done above, please check if there's multiple track. If there's, please adjust the pitch rod of each blade to eliminate it.
If there's still multiple track after adjustment. Please tell me, it may be caused by the inaccurate hole drilling on hub. The head is made by me. I'll change you a new hub.

Thank you.

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06-17-2013 07:48 PM  5 years agoPost 8
cueman100

rrApprentice

Santa Clarita Ca. USA

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Thanks for all the reply's guys.
I checked all 4 of my blades, they are the scale matt black 700mm spinblades, they all weigh exactly the same, and they all balance at the same point. I adjusted the pitch of each blade at mid stick at +5 degrees, I still get vibration on the skids. I put the flybar head back on the heli, and went into a low hover in my garage, and no vibration.I did that to insure that my main shaft wasne't bent. This morning I put the 4 blade head back on, and hovered it in my front yard, and same problem with the vibration. Young said in the previous post that it may be because of a bad hub
he is probably right, I don't think that I will send it back to him, as I really don't like the design of the blade grips, I would rather have them all one piece as in most other multi blade heads. It is really a cool looking head, but right now that is all I can say good about it. I am going to go with another brand head and see how that works out.

Again Thank you for all the reply's guys

Jim

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06-17-2013 08:51 PM  5 years agoPost 9
modtron

rrKey Veteran

Oxford. UK

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That's a shame Jim as the head with Spin Blade flies great.
If the offer of another hub is on the cards why not get it sent over and give it a go - shouldn't cost you anything - right ?

modtron
Oxford UK

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06-17-2013 10:46 PM  5 years agoPost 10
cueman100

rrApprentice

Santa Clarita Ca. USA

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Hi Modtron,

I've been playing around with this head for about 3 months and I've been having one problem after another with it Forjust one instance, try and find a linkage screw on line 3mmX35mm.
It's a bastard size no one I can find makes them, lots of 3 X30 but no 3x35. That's just one example. Another is the swashplate sucks, got all the screws tight but there is about .03mm slop between the upper and lower swash.It's like the joint ball is to large for the swash.I'm just tired of messing with the head. I found another head, it is ugly lol but Im going to try it.
Thanks for your concern anyway.

Jim

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06-19-2013 04:10 PM  5 years agoPost 11
CopterDr77

rrNovice

West Plains MO USA

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I have a friend who just bought a Deao head and blades. They're a two bolt system, like Vario's , but way cheaper. Not sure what sizes are out, but I know he has 450's and is building bigger.

Just a thought.

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06-19-2013 06:01 PM  5 years agoPost 12
coptercptn

rrElite Veteran

Mesa AZ. USA

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DEAO is only building (Currently) a 3 blade head in anything above a 450 size. I am testing his 5 blade for 450 and it is sweet.. Basically a Vario knock-off downsized... and yes, two bolt blades.

Home of the "Sea Cobra".....

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06-19-2013 07:23 PM  5 years agoPost 13
munkey nuts

rrApprentice

wales uk

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ive flown the three bladed version of this head, i had the blade grips bolt loose and the next bolt loose aswell.
it flies fine for me.

gaz

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