RunRyder RC Helicopter Topic - Carbon Extreme Dampers in Evo Freya Head Problem

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HIROBO Turbulence - SDX - Freya - Sceadu > Carbon Extreme Dampers in Evo Freya Head Problem

bobc1
Senior Heliman
Location: Southern California

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The force/thrust created by a threaded bolt/screw (essentially an inclined plane) is determined by the thread pitch & torque. F = 2T(3.1416 Pi)/P where F = force, T = torque, P = thread pitch.

The above numbers would represent a perfect scenario without taking into account thread friction that can account for a very high percentage of the torque & the fact that a 4mm diameter bolt should break before exerting the above forces.

I believe that the most force that a high quality 4MM (.1575"

diameter bolt with 150,000 PSI tensile strength should be able to create without damage is approximately 3,000 lbs

Cross section (not counting threads) is (3.1416 Pi)R squared. R = D/2. (3.1416 Pi)(.0787)(.0787) = .0195 X 150,000 PSI = 2,921 lbs.

EDIT: I don't know why the smiley icon shows up after the .1575" several lines above. It should be a ) but I don't seem to be able to change it.

02-19-2006 Over year old.

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The_Widowmaker
Key Veteran
Location: Bakersfield, CA

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Ok now I'm concerned after reading all these posts. I have an EVO 50 and CE dampers on the way. Is there a potential problem with the EVO 50 head and/or these dampers?

"I'm a Virgin.. I'm just not very good at it. "

02-19-2006 Over year old.

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Super Phreek
Veteran
Location: Sunny Lancaster, California

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I have been through several sets of CS dampners on both of my EVO 50. These were using the plastic heads. I have yet have an issue using the dampners. They do last a lot longer than the standard Hirobo dampners.

The dampner install on the 50 vs the 90 are completly different. There is nothing to worry about on the EVO 50....

Bob, what is with the smiley face

Derek

If you're not flying low; you're not flying

02-19-2006 Over year old.

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bobc1
Senior Heliman
Location: Southern California

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I agree with Super. Different system from Evo 50. Additionally, I have another set of CX dampers in another Evo 90 that work just great. This did not occur while flying.

I'm still thinking an error in dimensions...but...I'm waiting to receive the new ones before stating such.

02-19-2006 Over year old.

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The_Widowmaker
Key Veteran
Location: Bakersfield, CA

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Thanks for clearing that up. I just found out that these are not the dampers that are on the way. A different brand completely but nice to know if I do ever get these.

"I'm a Virgin.. I'm just not very good at it. "

02-20-2006 Over year old.

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u.k. sailor
Veteran
Location: cambs uk

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just to also add i have no problems with CX dampers in my EVO 50

02-20-2006 Over year old.

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d3sbo
Senior Heliman
Location: cambridge uk

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I fitted 414410 - YOKE SSZ-III with cx dampers with 60 o ring and white part A and they it still ridged

02-20-2006 Over year old.

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bobc1
Senior Heliman
Location: Southern California

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The Rest of the Story

Augusto sent a 2nd set of dampers to me.

After inspecting the 1st set of dampers & comparing them to the 2nd set, I discovered that the aluminum T Bushings were very similar in dimensions but the hard white plastic dampers varied greatly (even in the 2nd set, also).

The aluminum T Bushings included in the 2nd set had a substantial burr on the inside of the larger "T" diameter that I removed with a small file.

The following photos indicate the dimensions of the 1st & 2nd set of "D" dampers.

I de-burred & removed material until all four dampers were .107-.108" in width. This changed the pre-load compression on the 75 Durometer O Rings from .029-.035" to about .012".

I have not assembled these dampers on the head yet but I doubt that this pre-load will create any problems.

I never received the desired dimensions from Augusto.

03-07-2006 Over year old.

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bobc1
Senior Heliman
Location: Southern California

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I assembled the modified "D" dampers (.107-.108" in width) with the 75 durometer O rings (no shim washers) in the new Evo head today....NO PROBLEMS.

My $.02: If you purchase the CX damper system for your Evo Freya, measure the hard white plastic dampers prior to installing them. If they are more than .107-.108" in width, remove material before tightening the through bolt.

03-10-2006 Over year old.

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Super Phreek
Veteran
Location: Sunny Lancaster, California

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Wow,

That's pretty bad when one pays 60 bucks for some dampners, then has to modify them so they will not break things....

Derek

If you're not flying low; you're not flying

03-10-2006 Over year old.

PROFILE PM EMAIL POSTS BUDDY IGNORE GALLERY

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HIROBO Turbulence - SDX - Freya - Sceadu > Carbon Extreme Dampers in Evo Freya Head Problem

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