Kolibri
FW and Gyros
- Joined
- Oct 17, 2014
- Messages
- 1,636
- Location
- Wyoming
- Aircraft
- Cessna 152, 172, 172RG, 177, 206 -- Piper 180 -- RV-7A -- Calidus -- RAF2000 -- Sport Copter II and
- Total Flight Time
- 1000+
Howdy all,
Currently I'm owner-assisting my A&P during my RAF's annual condition inspection. He pressed into the rotor bearing block my new SKF 3206 A-2RS1 bearing. (The rubber sealed original 3206B.2RSR looked and felt fine, but after its 316 hours it should have been replaced 116 hours ago by "the gentleman from Brewton" when it was under his -- ahem -- "care".)
The RAF parts .doc file has some very wonky numbers that had my Local Bearing Store Guy scratching his head: 30262RFC3, 3026B2RFC3, 3026B 2RSRTVH. Seems somebody had numerical dyslexia, and typed in "3026" instead of the correct 3206, as well as a phonetically similar "RF" for RS. Well, we figured it out, eventually. (While some mfg. still use "5206" nomenclature, the more recent number is 3206.)
The "C3" refers to radial slack between the inner and outer rings being greater than the standard clearance to allow for thermal expansion and reduce Brinelling. I'm not yet convinced such is necessary in a gyro, but others seem to recommend a C3 spec bearing.
Harry S. has used 3206B 2RFC3 and 3206B 2RSR TVH.
Please don't be tempted by the false economy of some $20 Asian or Indian bearing. Spend another $30 for a Germany FAG or Austrian SKF, certified ISO 9001. Try www.ericbearing.com, for example.
SKF 3206 A series are equivalent to 3206 B of mfg. FAG.
These have no fill slots, and can be installed either side up.
I went with the SKF 3206 A-2RS1 (equivalent to the FAG 3206B.2RSR), with two rubber seals. I think a sealed bearing makes sense, especially if one replaces it every 200 hours as a prudent precaution.
The other SKF option was their 3206 A-2RS1TN9/MT33 (which uses a different cage material and grease).
The next post is about torque value of the rotor bolt.
Currently I'm owner-assisting my A&P during my RAF's annual condition inspection. He pressed into the rotor bearing block my new SKF 3206 A-2RS1 bearing. (The rubber sealed original 3206B.2RSR looked and felt fine, but after its 316 hours it should have been replaced 116 hours ago by "the gentleman from Brewton" when it was under his -- ahem -- "care".)
The RAF parts .doc file has some very wonky numbers that had my Local Bearing Store Guy scratching his head: 30262RFC3, 3026B2RFC3, 3026B 2RSRTVH. Seems somebody had numerical dyslexia, and typed in "3026" instead of the correct 3206, as well as a phonetically similar "RF" for RS. Well, we figured it out, eventually. (While some mfg. still use "5206" nomenclature, the more recent number is 3206.)
The "C3" refers to radial slack between the inner and outer rings being greater than the standard clearance to allow for thermal expansion and reduce Brinelling. I'm not yet convinced such is necessary in a gyro, but others seem to recommend a C3 spec bearing.
Harry S. has used 3206B 2RFC3 and 3206B 2RSR TVH.
Please don't be tempted by the false economy of some $20 Asian or Indian bearing. Spend another $30 for a Germany FAG or Austrian SKF, certified ISO 9001. Try www.ericbearing.com, for example.
SKF 3206 A series are equivalent to 3206 B of mfg. FAG.
These have no fill slots, and can be installed either side up.
I went with the SKF 3206 A-2RS1 (equivalent to the FAG 3206B.2RSR), with two rubber seals. I think a sealed bearing makes sense, especially if one replaces it every 200 hours as a prudent precaution.
The other SKF option was their 3206 A-2RS1TN9/MT33 (which uses a different cage material and grease).
The next post is about torque value of the rotor bolt.
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