akreiff

Hey guys, me again. The newbie.

I have not flown my new B400 yet but everytime I run it up on the driveway it seems to have some excessive vibration. I have already replaced the stock wood blades with the optional E-flight carbon fiber blades and very carefully balanced both blades using a HeliMax blade balancer. I do not know how much vibration is normal with a helicopter. Any advice would be greatly appreciated.

Thanks.

Alan

choppersrule

Akreiff,

There should be NO VIBRATION at all. I may recommend, to take the main blades off and the tail blades off.
Then spool the helicopter up to about 1/2 to 3/4 throttle, if you feel and or see any vibrations, you may have the flybar out of balance.
If that's the case, mark one flybar paddle and use it as a referrence. Move flybar, left or right about 1 or 2 mm. Then spool up again. If it's worse, you moved it the wrong way. Readjust as needed and repeat. Add tail blades and spool up. Add main blades and spool up.
Process of elimination. Oh, make sure that the tracking of the blades and pitch is per the manual. Takes alot of work.

Dave / Choppersrule

Wolfpackin

Where are you seeing this vibration?
Is it a fine high frequency vibration that causes the tail fins to blurr?
Or is it a violent shaking of the heli?

Please try to describe what you are experiencing in more detail if you can.

rotarydoc

Hey Alan,

How fast are you spinning the blades up? If not up to nearly take off speed, it may just be that the blades have not "settled in" so to speak... as the rotor head speed goes up, the blades will naturally straighten out to their normal position. At lower speeds, it may cause some shaking of the heli on spin up of the blades. Also, make sure that the blades are not too tight in the grips, they should be able to be moved with a small amount of resistance, but not flopping around, either.

You may need to get the rotor/head speed up to almost take off speed to eliminate this perfectly normal behavior...if it still vibrates at or near hovering speed, you may indeed have an issue.

Hope this helps some...

Glenn

xyster101

+1 to rotarydoc. It needs to be at about half stick for the blades to settle. If you did what Chopperrules said, also try adjusting the tension on the main blade bolts. It should be tight enough the blades have some resistance to move, but not too tight where they stay put if you push on them.

casey_lamm

small amounts of vibration at low head speeds is pretty normal. Depends on how violent. If you can get a video of it it will tell us alot more.

I had a bent main shaft. It was completely flyable, but it would vibrate until it was spooled up. Have you had any rough landings. Is this heli new out of the box?

Check rotor tracking, its not that hard to do. All and make sure the leading edge of the blades are in the correct position. Yes, I will atest they can go in backwards. The heli doesn't like it at all!

akreiff

Thanks for all the input. Being brand new to RC helis (not new to airplance RC) means any advice is much appreciated. I don't have video to show you. The vibration is very minimal is at fairly low throttle settings. I have not flown this heli yet and no one else has either. As stated earlier I replaced the stock wood blades with Horizon's 325mm carbon fiber blades and balanced them very carefully using a Heli-Max roter blade balancing tool. Blade tracking appears to be fairlly close but the new carbon fiber blades are of course black in color. They almost disappear when you get the rotor head up to a decent speed. I suppose I need to get ahold of some bright yellow tape and some red tape so I can more accurately tell if both blades are tracking correctly.

I do belive I will take Choppersrule's advice and take off the main blades and the tail rotor blades and run the heli up to 1/2 to 3/4 throttle and see how the vibration is then.

Thanks for your advice and help.

Alan

JPEE

Hey Alan,

A suggestion if I might. Go to your local auto parts store and buy two rolls of auto pin stripping tape. It is vinyl and narrow and comes in colors. If for some reason you can't find that tape there go to Home Depot and in the Electrical Dept there is vinyl tape we use in the electrical trade to color code wires. It comes in Yellow, Red, Blue, Green and White.
That should set you up my friend.....

JPee

vince.b

My Feedback: (1)

I have not read the thread..
make sure the blades are tracking.

casey_lamm

I would also recommend saving the carbon blades for when you are better and doing 3d. The cheap wood ones are fine to learn on and less expensive to replace.

Pilotwoody

I have the Blade 400 as well. When powering up I find that the tail always shakes from about one quarter to just above half throttle. When I first started with the Blade 400 I also thought something was wrong, because I wouldn't get the throttle any further than that (I got scared!!). But once I started to push the throttle a little further it just smooths out and the shaking doesn't come back. And it seems to fly okay, but having no other singe rotor experience I have nothing to compare it to.

choppersrule

Pilotwoody,

By your description of the shakes, I think you may have the main blades a little tight on the grips. Try loosening the blade screws about 1/4 turn and retry. I think it may help ya.

Dave / Choppersrule
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vince.b

My Feedback: (1)

the vibe can be as simple as the baldes to tight to the blades not tracking.
also if you balance the blades incorrectly. ie adding the balace tape in the wrong place.

mydartswinger

Along the lines of vibration. Would a vibration being caused by a bent flybar cause a heli to hover like [link=http://www.rcuvideos.com/item/VKXLWSDCMJ2XQBBZ]this[/link]? Or is it mostly just me being a noob? The mild-moderate wind? Or a horrible concoction of all or some of the above?

By following chopper's advice, I was able to find the bent flybar after the flight in the linked vid. It seems as the majority of the vibration is gone after replacing the flybar, now it only has a slight high frequency vibration (after adding the blades, but they have been balanced, CG matched, and tracked. I also have checked the blade tension by making sure that when held by the boom with the blades parallel to the ground, they stay in place, but when gently shaken they fall about 45 degrees) at higher headspeeds, but you really can't see the vibration.

At lower headspeeds, the tail will shake about 1/4" to 1/2" off of the ground, but settles around half throttle. It does it mildly again when the headspeed slows down.

Thanks for the assists.

Pilotwoody

Thanks ChopperRule,
That seems to have been the problem, no more shaking.

wsdepa

Do yourself a favor and put the woodies back on. You are going to trash those expensive carbons until you learn to fly ( maybe in a year or so). If you put three or four inches of electricians tape along the leading edge of the blades and then one wrap all the way around the tip (trim with scissors) you will find that the woodies will survive several crashes.
You will learn all about trouble shooting vibration when you rebuild after your first crash.
Good luck.