Rotary Wing Forum  

Go Back   Rotary Wing Forum > Rotorcraft > General Discussion

Reply
 
Thread Tools Rating: Thread Rating: 20 votes, 5.00 average. Display Modes
  #16  
Old 05-09-2014, 12:11 PM
eddie's Avatar
eddie eddie is offline
Gold Supporter
 
Join Date: Jan 2011
Location: Polvadera,nm 87828
Posts: 1,005
Default

isn't the load being applied to the bottom of the bearing race,the rotor is pulling the race of the

bearing up and the load will be on the bottom side of the race and upper side of the inner cone.

best regards,eddie.....
__________________
Eddie Sigman,polvadera,nm
(575) 835-4921
Reply With Quote
  #17  
Old 05-09-2014, 01:48 PM
Alan_Cheatham Alan_Cheatham is offline
Member
 
Join Date: Nov 2003
Location: Dallas, Texas
Posts: 1,704
Default

Quote:
Originally Posted by madwinger View Post
Ok I read the thread and sorta understood but I am not technical in the least this way. I asked the same question to Mike and Chuck that I am going to ask here.

What bearing would you use in this application. Is the 3206 A-2RS1TN9 /MT33 the only one available for this application or is there something better?

Thanks again for your input.

Mark
The bearing is a dual row, angular contact (30 degree), and most typically with two rubber seals.

The old bearing number was 5206CZZ, this is the MRC designation, C being Conrad (normal bearing, a non max bearing), and two rubber seals. This bearing also used a steel bearing cage.

Note that while other manufacturers use 2RS to designate two rubber seals and ZZ for two metal shields MRC was different and used ZZ for two rubber seals.

SKF purchased MRC and replaced the 5206 with the 3206, although you might find some boxed bearings marked with both numbers. So, my recommendation based on this post: http://www.rotaryforum.com/forum/sho...06&postcount=8


would be 3206 A 2-RS1M MT33, the A being equivalent with the MRC C designation (Conrad), two rubber seals, and solid brass cage.

.
Reply With Quote
  #18  
Old 05-09-2014, 01:58 PM
Alan_Cheatham Alan_Cheatham is offline
Member
 
Join Date: Nov 2003
Location: Dallas, Texas
Posts: 1,704
Default

Quote:
Originally Posted by eddie View Post
isn't the load being applied to the bottom of the bearing race,the rotor is pulling the race of the

bearing up and the load will be on the bottom side of the race and upper side of the inner cone.

best regards,eddie.....
The bearing balls can only carry the axial load from rotor thrust by being in compression between the bearing races so only one row of balls, the top, is carrying the axial load. This is why, if a bearing with a loading slot is used, the slot should be at the bottom of the bearing block.

.
Attached Thumbnails
Click image for larger version

Name:	Angular Contact Bearing.jpg
Views:	267
Size:	76.2 KB
ID:	111650  
Reply With Quote
  #19  
Old 05-09-2014, 02:08 PM
eddie's Avatar
eddie eddie is offline
Gold Supporter
 
Join Date: Jan 2011
Location: Polvadera,nm 87828
Posts: 1,005
Default

thanks for good the explanation.

best regards,eddie.....
__________________
Eddie Sigman,polvadera,nm
(575) 835-4921
Reply With Quote
  #20  
Old 05-11-2014, 02:08 PM
madwinger's Avatar
madwinger madwinger is offline
OldFartium Member
 
Join Date: Apr 2013
Location: Bountiful, Utah
Posts: 699
Default

Quote:
Originally Posted by Alan_Cheatham View Post
The bearing is a dual row, angular contact (30 degree), and most typically with two rubber seals.

The old bearing number was 5206CZZ, this is the MRC designation, C being Conrad (normal bearing, a non max bearing), and two rubber seals. This bearing also used a steel bearing cage.

Note that while other manufacturers use 2RS to designate two rubber seals and ZZ for two metal shields MRC was different and used ZZ for two rubber seals.

SKF purchased MRC and replaced the 5206 with the 3206, although you might find some boxed bearings marked with both numbers. So, my recommendation based on this post: http://www.rotaryforum.com/forum/sho...06&postcount=8


would be 3206 A 2-RS1M MT33, the A being equivalent with the MRC C designation (Conrad), two rubber seals, and solid brass cage.

.
Alan, I did a Google on that bearing and the only thing that comes up is the reference to this forum. I did find lots of these 5206CZZ. Steel Cage. Is this the one I want?

Thanks

mark
__________________
Fly often, fly safe.

Mark Archibald
Bountiful, Utah
Parting out Air Command Elite CLT N138LB

Last edited by madwinger; 05-11-2014 at 03:50 PM.
Reply With Quote
  #21  
Old 05-11-2014, 08:47 PM
Alan_Cheatham Alan_Cheatham is offline
Member
 
Join Date: Nov 2003
Location: Dallas, Texas
Posts: 1,704
Default

Quote:
Originally Posted by madwinger View Post
Alan, I did a Google on that bearing and the only thing that comes up is the reference to this forum. I did find lots of these 5206CZZ. Steel Cage. Is this the one I want?

Thanks

mark
http://www.mscdirect.com/product/det...72292#features

http://www.mscdirect.com/FlyerView?p...alogs/big-book

There are I'm sure other suppliers but be prepared to pay a good price for a quality bearing. Bearings costing $15 or so are not what you want.

Also, while a brass cage may be more desirable, given the steel caged 5206's successful history in gyro use I wouldn't shy away from using one.

.
Reply With Quote
  #22  
Old 05-12-2014, 12:58 AM
madwinger's Avatar
madwinger madwinger is offline
OldFartium Member
 
Join Date: Apr 2013
Location: Bountiful, Utah
Posts: 699
Default

Quote:
Originally Posted by Alan_Cheatham View Post
http://www.mscdirect.com/product/det...72292#features

http://www.mscdirect.com/FlyerView?p...alogs/big-book

There are I'm sure other suppliers but be prepared to pay a good price for a quality bearing. Bearings costing $15 or so are not what you want.

Also, while a brass cage may be more desirable, given the steel caged 5206's successful history in gyro use I wouldn't shy away from using one.

.
Cant thank you enough Alan. I am now educated and armed with the info I need to make and informed decision.

This thread will be an invaluable resource for those who are in the same floundering boat as I am. Especially with the bearing block pictures that explains the proper positioning.

Mark
__________________
Fly often, fly safe.

Mark Archibald
Bountiful, Utah
Parting out Air Command Elite CLT N138LB
Reply With Quote
  #23  
Old 06-27-2014, 10:56 AM
cbonnerup's Avatar
cbonnerup cbonnerup is offline
More Senior Every Day
 
Join Date: Aug 2010
Location: Greenville, NC / USA
Posts: 508
Default General RotoHead Re-Work

Group,
I have recently purchased a Barnett Rotorhead from a fellow member.
NICE piece of work! Mr. Barnett was a talented craftsman and machinist. I am bringing it back from long sleep and have ordered a new bearing (Nachi 5304ZZ). Original? was a ND5304(ZZ type), which was made in the USA by New Dimensions Bearings, now kaput. Looked and felt good and was well lubed, but caution abounds.

Question: Quite a few fasteners on the head, most under load stress rather than shear. I need to decide to go ahead and replace all or? The 'Jesus' bolt will be replaced, just wondering about the rest? Magnafluxed the spindle and looks great; I would hope so being 4130 steel!

Slight surface corrosion but overall they look good when given a bath`. Will use new locknuts (MIL spec expanding nuts rather than nylock.

Comments please.
Thanks,
Chris
Reply With Quote
  #24  
Old 08-22-2014, 09:29 AM
madwinger's Avatar
madwinger madwinger is offline
OldFartium Member
 
Join Date: Apr 2013
Location: Bountiful, Utah
Posts: 699
Default

Quote:
Originally Posted by MadMuz View Post
Hi Chris, I am a bit of a 'scaredycat' when it comes to things like rotor heads which I don't know the complete, true history of, so my advice would be disassemble, good clean of parts.... extra good inspection of parts (magnifying glass, magnet and wet iron filings).... I would replace every bolt and the bearing. If you know and trust the member you bought it from.... and he actually knows the complete true history... different story perhaps.... but I would still replace all bolts.... especially since you mention that four letter word 'corrosion' (ok, 9 letter word)

Madwinger, the bolts all one way thru the rotorhead, is so you know which direction the head is in relation to the rotors. When you put new rotors on a machine and test fly it, it is a good practice to note smoothness.... land lift out rotors, turn head 180 degrees, replace rotors.... fly to see if they are smoother, the same smoothness or rougher. Then you note which way was smoothest, lets say blade B to the right when the heads of the 2 bolts in your rotor head are facing you (threads away). With your head with one bolt each way, if you turn the head 180 degrees it still looks identical. If you don't want to pull a bolt and put it in from the other side, you can just put a little paint on each side of the head teeter fork... so when the red side faces you, blade B goes to the right.... this way the rotors are in the head so they run the smoothest each time. Oh, and don't forget to turn your cotton reals (teeter bolt bushes) whenever you remove or refit the rotors, so teeter bolt doesn't always bear the weight and wear the cotton reels in exactly the same place, forever
MadMuz, That is good advise. Thank you, I appreciate it.

mark
__________________
Fly often, fly safe.

Mark Archibald
Bountiful, Utah
Parting out Air Command Elite CLT N138LB
Reply With Quote
  #25  
Old 08-22-2014, 12:40 PM
cbonnerup's Avatar
cbonnerup cbonnerup is offline
More Senior Every Day
 
Join Date: Aug 2010
Location: Greenville, NC / USA
Posts: 508
Default Scared-y-Cat

Thanks,
I too am a scaredycat.
Had a not-so-good landing due to things mechanical in a Quicksilver on my first introductory flight; a WHILE back. I tend to question everything re: aircraft since; sometimes to my detriment I suppose.

Appreciate your comments,
Chris


Quote:
Originally Posted by MadMuz View Post
Hi Chris, I am a bit of a 'scaredycat' when it comes to things like rotor heads which I don't know the complete, true history of,...
Reply With Quote
  #26  
Old 09-03-2014, 08:46 AM
LDay LDay is offline
Junior Member
 
Join Date: Jul 2014
Location: Brisbane, Qld
Posts: 4
Default

Nobody has mentioned the type of bearing, I one of my machines I used twin tapered roller bearings. Both outer tracks,fit in recessed bores so it is impossible for them two move.With no central spacer. Another type of bearing is angular contact, but they can fail, if worn or out of adjustment. IE early VW front wheel bearing. They are improved, with a central spacer. It must be an exact fit however.
Reply With Quote
  #27  
Old 09-29-2014, 02:36 AM
LDay LDay is offline
Junior Member
 
Join Date: Jul 2014
Location: Brisbane, Qld
Posts: 4
Default

Why don't you use tapered roller bearings, that way you can adjust the preload.
Reply With Quote
  #28  
Old 09-29-2014, 02:38 AM
LDay LDay is offline
Junior Member
 
Join Date: Jul 2014
Location: Brisbane, Qld
Posts: 4
Default

Does any one know if, contra rotating rotors will auto rotate.
Reply With Quote
  #29  
Old 09-29-2014, 01:56 PM
XXavier XXavier is online now
Member
 
Join Date: Nov 2006
Location: Madrid, Spain
Posts: 580
Default

Quote:
Originally Posted by LDay View Post
Does any one know if, contra rotating rotors will auto rotate.
Yes, they will. Cierva's first autogiro, the C1, was fitted with superimposed, contra-rotating rotors. The autogiro did not flew, but the rotors worked...
Reply With Quote
  #30  
Old 11-30-2014, 06:51 AM
HH60FE HH60FE is offline
Junior Member
 
Join Date: Nov 2014
Location: Seoul
Posts: 1
Default

HI im sorry for unmatched reply but im looking for FE of HH60 Black hawk
and i have no idea where can i find them!
Im ROKAF segeant, Black hawk FE!
Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -8. The time now is 01:48 PM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Ad Management plugin by RedTyger
You Rated this Thread: