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Old Apr 06, 2012, 04:11 AM
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United States, AZ, Mesa
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Yeah I'm " that guy"

But I don't want it to sound like a harse post. If I can get answers that's great. If not the I guess its just business as usual.
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Old Apr 06, 2012, 04:31 AM
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that cool, i understand, i always want to know more about things then they want to tell you so i just go digging untill i find out what i want to know........

i'll say this, skookum sure has been tight lipped about all the stuff they are working on right now.......

oh and is it just me or does it seem like sense georgi has become a "mod" that over time he has been more and more throwing his weight around and pushing his personal opinions on people ? i thought "mods" we're supposed to stay impartial and not take shots at people who don't share his opinion ???
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Old Apr 06, 2012, 06:35 AM
RCHN #150
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Lawrenceville, GA
Joined Nov 2007
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Originally Posted by GetToDaChopper View Post
ran it through a battery of tests and it passed with flying colors, now all i need now is the new firmware update that lets you "zero the sensors" and it will be ready for the quad that i have been planning on building ever since i removed it from my Mini Protos a while back !
Wow. Good for you! I'm really impressed. Do you have a good picture of it before your fix? I think I'll take a look at my "questionable" unit.

The latest rumor for the firmware update is Monday. But, we all know not to hold our breath.

Rick
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Old Apr 06, 2012, 09:16 AM
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no i wish i did, the first time i heated it up it laided down flat ok but then my dad looked at it and pointed out that it wasn't squared with the marks on the board so i heated it up again and lined it up with the marks (one mark in all four corners) then got the heck away from it and let it cool back down, one wrong little bump and the surface tension of the molten liquid solder wouldn't be enough to hold all of the other components in place and if that happened i would have had one big mess on my hands !

i always say "i'd rather be lucky then good" !

P.S. it always seems like the firmware updates come out on Mondays, i wish they came out on fridays so you could mess around with them on the weekends.... lol
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Old Apr 08, 2012, 12:03 PM
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Georgia, USA
Joined Jan 2008
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After replacing the bearings and installing the hardened shaft in the stock round tailcase on my Logo 5003D I had a noticible improvement in the vibrations. It was not where I wanted it to be but was better.

I ordered the upgrade carbon tail assembly but I could see no reason for this to improve the situation.

I ordered a complete tail rotor assy.hoping that maybe there was a bad thrust or radial bearing in the existing one. It sure felt good in hand. It was smooth and showed no binding at all.

Last Saturday I tried the SL feature and was pleased to see that it actually worked. After working for the first pack the SL kicked off on the second pack. I landed, rebooted and took off again only to have it kick off again. I was able to keep SL working for the remaining flights by taking it easy and not barking the blades. I fiddled with the heli that night and had no shutdowns Sunday but the logs showed some peaks near 7.

Yesterday I removed the tail rotor assy and yoke assy and ran a bench test. Then I added everything eacept the rotor blades and ran another test. Next I added the blades and was pleased to find that the new rotor assembly lessened the vibes considerably.

I may not be able to do much about the vibes at 300-400 as I believe that the Scorpion 4020-1100 is responsible. The end play feels just right and this was a new motor. I had a different 4020-1100 on the Logo when I first installed the SK unit and it had a lot of time on it.

I am about to take it out into the garden and give it a whirl. I expect (hope) that the log will be a bit better in the air.
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Old Apr 08, 2012, 03:46 PM
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Quote:
I think I'll take a look at my "questionable" unit.
hey rick have you had a chance to look at that yet ?

i was just curious if mine was the only one like that or if there's more out there.......
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Old Apr 08, 2012, 10:00 PM
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United States, MN
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Alright any help here is much appreciated. I've got what started out as a HK500CMT but is now a mutant of HK/Align parts after a few crashes last year. Now I've upgraded to an RJX FBL head and the SK720. I'm getting really bad vibrations at about 200 Hz / 12000 RPM. I think the issue is with the tail. I've tightened everything down and replaced the blades but it seems to make no difference. The tail is belt drive and has an Align aluminum boom. Rest of the tail is stock HK metal. The heli flies fine but I would like to get this figured out so I can use SL as a bailout since I'm still learning. I've attached a log.
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Old Apr 08, 2012, 10:27 PM
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Lawrenceville, GA
Joined Nov 2007
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Originally Posted by GetToDaChopper View Post
hey rick have you had a chance to look at that yet ?

i was just curious if mine was the only one like that or if there's more out there.......
Not yet. I need the front torque tube drive - hope to pick one up tomorrow. I want to get the heli trimmed out and try S/L before I rip it open

Also want to try the re-calibration.

Rick

PS: HeliDirect has the SK540 on their web page.
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Old Apr 08, 2012, 10:32 PM
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Lawrenceville, GA
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Originally Posted by grimbeaver View Post
Alright any help here is much appreciated. I've got what started out as a HK500CMT but is now a mutant of HK/Align parts after a few crashes last year. Now I've upgraded to an RJX FBL head and the SK720. I'm getting really bad vibrations at about 200 Hz / 12000 RPM. I think the issue is with the tail. I've tightened everything down and replaced the blades but it seems to make no difference. The tail is belt drive and has an Align aluminum boom. Rest of the tail is stock HK metal. The heli flies fine but I would like to get this figured out so I can use SL as a bailout since I'm still learning. I've attached a log.
Yes, it is the tail. Most of the vibration is fore-aft - which indicates the blades may be out of balance.

Take off the mains and tail blades. Spin it up to get a vibration log and see if these go away. If that doesn't help, replace the tail shaft and try it again. The last option would be bad bearings.

Rick
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Old Apr 08, 2012, 10:39 PM
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Lawrenceville, GA
Joined Nov 2007
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Quote:
Originally Posted by jamesppp View Post
After replacing the bearings and installing the hardened shaft in the stock round tailcase on my Logo 5003D I had a noticible improvement in the vibrations. It was not where I wanted it to be but was better.

I ordered the upgrade carbon tail assembly but I could see no reason for this to improve the situation.

I ordered a complete tail rotor assy.hoping that maybe there was a bad thrust or radial bearing in the existing one. It sure felt good in hand. It was smooth and showed no binding at all.

Last Saturday I tried the SL feature and was pleased to see that it actually worked. After working for the first pack the SL kicked off on the second pack. I landed, rebooted and took off again only to have it kick off again. I was able to keep SL working for the remaining flights by taking it easy and not barking the blades. I fiddled with the heli that night and had no shutdowns Sunday but the logs showed some peaks near 7.

Yesterday I removed the tail rotor assy and yoke assy and ran a bench test. Then I added everything eacept the rotor blades and ran another test. Next I added the blades and was pleased to find that the new rotor assembly lessened the vibes considerably.

I may not be able to do much about the vibes at 300-400 as I believe that the Scorpion 4020-1100 is responsible. The end play feels just right and this was a new motor. I had a different 4020-1100 on the Logo when I first installed the SK unit and it had a lot of time on it.

I am about to take it out into the garden and give it a whirl. I expect (hope) that the log will be a bit better in the air.
Jimmy,

I've never seen anything like this.
Excuse my dumb questions:

(1) Is the main shaft "tight"? I can't imagine where you are getting the up and down vibrations. Can the main gear move up and down?

(2) The fore-aft vibrations are usually from the tail. Either new tail blades, or a new tail shaft should help, as you noted.

(3) I'm stumped. I would tear it down. Did you replace all shafts, or just bearings?

Rick
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Old Apr 09, 2012, 02:43 AM
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Quote:
PS: HeliDirect has the SK540 on their web page.
ya that's cool, but of course they have none in stock....


grimbeaver

you might want to look carefully at the blade grip bearings, screws and washers, sometimes the bearing aren't pressed in (seated inside) all the way or they might just be bad, when the outside grip bearing starts to go bad it no longer holds the blade grip the same distance from the centerline of the tail shaft causing an imbalance in the tail rotor assy and the same go's for bearings that aren't pressed in all the way, or even screws and washers that are not the same weight in the rotating tail assy can cause a imbalance in a tail rotor that is rotating at approximately 12,000 RPM's.

when something is turning as fast as the tail rotor (approximately 12,000 RPM's) it only takes a small fraction of a gram on one side more than the other on a tail assy with little mass to start with to cause some big vibrations........


oh and in case you somehow see this jimmy, a tail rotor can also cause up and down vibrations with a 720, it's actually easier for a out of balance tail rotor to swing a heli up and down ver pulling the mass of the hole heli fore-aft, one more thing to consider is something out of whack with the main rotor blades like tracking or blades that aren't lifting the same for whatever reason can cause up & down vibs.

you just have to remember that vibration that is caused by a out of balance condition (and excluding the shock type) is just accelerations that are oscillating back & forth, up & down, left & right or in what ever plain the oscillation happens to be in......
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Old Apr 09, 2012, 04:54 AM
A man with too many toys
United States
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Originally Posted by Rickn816 View Post
PS: HeliDirect has the SK540 on their web page.
Helidirect.com is taking orders and expects to ship next week. http://helidirect.com/skookum-roboti...r-p-26481.hdx?


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Old Apr 09, 2012, 04:57 AM
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Lawrenceville, GA
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I have my order in.

Rick
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Old Apr 09, 2012, 09:16 AM
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Georgia, USA
Joined Jan 2008
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Rick,
As far as the tail is concerned, everything is new other than the tail case itself . I do have the "upgrade" carbon tail assy which is the open case type. The new tail shaft is the "hardened' model Mikado offers for twice the price of the standard.

I replaced the main shaft with the "hardened" shaft they offer as well as the main gear. I did not replace the main bearings here
I don't think I accomplished anything replacing the main rotor parts. The FBL head is brand new Mikado stuff.
I flew it yesterday evening and it flies great and no cutoff on the SL. As long as the vibes don't cut off the SL I'm good with it
I can remount the SK directly under the main shfaft ising a piece of light ply or aluminum if want to move it. Bench runs with tail blades only show much less vibration here as the back shelf is a bit cramped for the S K.
If I don't get any shutdowns I will leave it as is I think. > 3.5 isn't too bad for a heli with this much airtime on it I wouldnt think
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Old Apr 09, 2012, 10:50 AM
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Originally Posted by jamesppp View Post
Rick,
As far as the tail is concerned, everything is new other than the tail case itself . I do have the "upgrade" carbon tail assy which is the open case type. The new tail shaft is the "hardened' model Mikado offers for twice the price of the standard.

I replaced the main shaft with the "hardened" shaft they offer as well as the main gear. I did not replace the main bearings here
I don't think I accomplished anything replacing the main rotor parts. The FBL head is brand new Mikado stuff.
I flew it yesterday evening and it flies great and no cutoff on the SL. As long as the vibes don't cut off the SL I'm good with it
I can remount the SK directly under the main shfaft ising a piece of light ply or aluminum if want to move it. Bench runs with tail blades only show much less vibration here as the back shelf is a bit cramped for the S K.
If I don't get any shutdowns I will leave it as is I think. > 3.5 isn't too bad for a heli with this much airtime on it I wouldnt think
What is your SK unit mounted to James? I used the Zeal gel using two split pieces under the edges of a metal plate and then used standard thin double sided tape to hold the unit on the metal plate. It made a huge difference over the supplied gyro foam tape.

http://www.readyheli.com/search.asp?keyword=Zeal+tape
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