RunRyder RC Helicopter Topic - Bad tail vibration on VE

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e-JR Vibe 500, Parkmite, Voyager-E > Bad tail vibration on VE

gpontis
Heliman
Location: Palomar Park, CA

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I assembled a VE with a combination of upgrade parts and new parts. The tail has a bad vibration. I spun it up with the main blades removed, then with and without the TR blades. There is vibration even without the TR blades, but it probably would not shake itself apart. With the blades on it is hard to hold on to the tail boom. I tried two sets of TR blades, no difference. My original VE does not have this problem. I notice two differences. The new one has slight play between the shaft and the bearings. The new one also has a PMP steel TR hub. The TR has never hit anything and the shaft looks perfect when spun slowly. Any thoughts where to look first ?

George

PS - the flanged bearings and tail case are brand new

03-28-2008 Over year old.

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ScaleCrazy
Heliman
Location: Salem, OR-USA

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Do you have another new tail rotor shaft to try? I've had a brand new JR tail rotor shaft be out enough to give a bad vibration.

03-28-2008 Over year old.

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dwoel
Heliman
Location: Millville, New Jersey

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One place that has given VE owners trouble with tail vibrations in the past, is the 2mm bolts holding the tail grips on. They are easily bent and can cause some serious vibration. Doesn't take much to bend them, and doesn't take much bend to cause the vibration. I've been flying my VE for close to 5 years now and always kept extra bolts on hand. I believe they are 2X10 mm. I can look up the part number if you want. Not sure that's your problem, but it has affected others in the past. Keep us informed of your progress.

03-28-2008 Over year old.

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gpontis
Heliman
Location: Palomar Park, CA

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The PMP TR hub has some special bolts that come with it. I have no idea where one would buy replacements for them. But that is a good point as I have replaced many of the stock 2mm bolts in the past on my original VE. Also I have replaced many tail shafts.

It turned out that I did not have any spare shafts and just ordered some this morning. They should be here in a few days, then I can start with that and keep going until I find the offending part. While looking I found a new set of flanged bearings and several stock aluminum hubs.

If I can get past this I should have a pretty nice VE. This one has a Kontronic 2100 KV motor that I am driving with 6S LiPo (2 x 3S 2100maH), a GY-401, and a fast S9253 on the tail. I also have some CyberHeli aluminum blade grips with thrust bearings, still in the bag though.

George

03-29-2008 Over year old.

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gpontis
Heliman
Location: Palomar Park, CA

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Removed the tail rotor shaft and, sure enough, it was slightly bent. I put in a new one and was very careful to not bend it. I ran it up with the mains removed and everything was very smooth to a point, then suddenly a lot of vibration. I stopped the motor, then tried again. It is still smooth up to a certain point, then vibration. I can see that the shaft starts vibrating in some mode above a certain RPM.

When stopped and I wiggle the rotor assembly a little, it is apparent that the outboard bearing assembly is not tight in the case. I am tempted to pull the shaft again, then push the bearing into the case as best I can and apply a drop of CA to lock it in place.

I checked RPM on the tail. These problems begin around 10K RPM. At max throttle and no load I am sure that it would be at 11K RPM or more. My understanding is that 10K RPM on the tail is 2K RPM at the head. So if the tail works consistently well up to 10K RPM then that should be enough.

Given the unsupported length of this shaft, I think that it would have been better if JR had either used a hardened shaft or a larger diameter. This shaft is 3mm. By comparison, a Logo 10 has a 5mm TR shaft. Oh well...

04-05-2008 Over year old.

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ScaleCrazy
Heliman
Location: Salem, OR-USA

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I've been where you are at and my solution to the problem was to replace all the tail components with K&S after market parts. I still had a vibration as well and have blown out two of their complete tails and I'm now on the third.

I bet I was not the only complaint they had as K&S has since beefed up their tail components for the Voyager E. I have not needed this upgraded tail as I determined that part of the problem was the tail belt was too tight. I would also suggest that you get tail boom supports as the resonance is reduced dramatically with them installed.

Here is a link to the

http://www.ks-j.net/kands/E_KS/sub_windw.cgi?2124

This tail now has a 4mm shaft.

http://www.ks-j.net/kands/E_KS/sub_windw.cgi?1175
http://www.ks-j.net/kands/E_KS/sub_windw.cgi?2110

I've not used these supports as my Voyager E is going in a scale fuselage so I can not attest to their performance.

04-05-2008 Over year old.

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Eddie M
Heliman
Location: Kanata, ONT, Canada

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Where can you get such upgrade from KSJ in North Americar?

04-06-2008 Over year old.

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ScaleCrazy
Heliman
Location: Salem, OR-USA

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Eddie,

There is no supplier that I've been able to find here in the US. The distributor of KSJ here in the United States is Advantage Hobby and they import very few of the upgrade parts for the Voyager E. I utilize a Japanese company, HobbyNet Japan. There are many others and some that discount which HobbyNet does not. You might try

http://homepage1.nifty.com/ishiimokei/english/index.htm

Not sure if they carry the full line but they do have the new Super Voyager E 4S nicely discounted.

04-06-2008 Over year old.

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gpontis
Heliman
Location: Palomar Park, CA

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I have an upgrade TR hub on this VE. I thought that it was PMP, but the bolts looks just like the ones on the K&S upgrade. One trouble with going this route is obtaining spare parts. Where could I ever find these bolts if they break ? Probably I would just have to replace them with 2mm socket head caps screws. That is not so bad, but what if it was thrust bearings, or a pitch control lever.

I test flew my VE after replacing the shaft and connecting an Eagle Tree data logger. It looks like I am just turning it too fast. I had a throttle curve at 80% in the center and 100% at the ends abd 16t pinion. The motor has Kv=2100 and I am using a 6S pack. This resulted in 2000 RPM head speed in hover, and at full up collective the head speed went _up_ to 2200 RPM. Given this, perhaps I run with a 15t motor pinion and configure for 85% throttle at hover. That should maintain 2000 RPM head speed under all conditions and maybe the tail hardware will be adequate if I don't over-rev any more than this.

George

04-06-2008 Over year old.

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HiroboEric
Veteran
Location: Los Angeles, CA.

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George make sure your flybar is straight. Your may have your paddles blades aligned but a slight bend in the flybar will throw in a hifrequency vibration through your tail. Usually looks like the tail blades are out of track.

Eric Pacheco, AirWorksRC.com

04-06-2008 Over year old.

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gpontis
Heliman
Location: Palomar Park, CA

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The flybar is good, never crashed or bent. When I install a flybar I do adjust it carefully before locking it down. I revved up the heli without the mains and without the TR assembly (but with tail shaft and belt). It was fairly smooth like that and I didn't think that it needed anything. Thanks for the suggestion though, I am sure that it would could produce a lot of vibration if the flybar was out of balance.

George

04-06-2008 Over year old.

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Spitfire1
Key Veteran
Location: Perth Australia

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Oh no, looks like ive got this same thing happening with my Ve.\
I have been down this track before with namely kyosho calibre 30 turning into a paint shaker at certain rpms, it took me the better part of 2 years and alot of heart ache and hard work too finally cut my losses, im going to loosen my tail belt, check( well i dunno what else too check, everything looks fine) and then give in before it destroys my gyro servo.
Damn

how can large companies like JR and Kyosho get away with releasing stuff onto the market like this, my 50 heli is an rjx, and my e 500 is a sonix hdx, both companies most people have probly never heard of me included, you would think that there a bit dodgy in that respect, but there the best helis ive owned, they only break when I crash em.

04-16-2008 Over year old.

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Spitfire1
Key Veteran
Location: Perth Australia

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just took it out for a fly, tail vibr no where nere as bad as it was last night, not enough to shake the heli apart or anything, but its still there like a constant tremor in the rear rotor, im going to keep on flying to see if maybe its dur to everything being new and tight as I dont think its bad enough to damage my servo.
Fingers crossed, maybe the tail rotor shaft was slightly bent out of the box but if it is its not enough to see.

04-16-2008 Over year old.

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Spitfire1
Key Veteran
Location: Perth Australia

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I think I found out the source of the vibr, there is a post on this forum about the tail slider melting down, this has obviously been happening and now happened