RAF Shimmy Dampners install photos

[eddie]

Kevin,
these are the install photos of the shimmy dampners on my RAF,they

were bought @ Ebay for about $25.00 each.What I like about these is that

the adjustment for resistance has about 20 settings,I started in the middle

and kept increasing the pressure until the vibration was gone and I still had good

cyclic movment.

 

[Kevin_Richey]

Nifty, Eddie!
Thanks for posting those photos.

 

[Kolibri]

You have about the most customized RAF I've seen.
Very clear photos, thanks, eddie.
Have you any part # or website links to these?

Other questions:

Are you certain that they would never lock up and thus prevent flight control?
Did you fabricate their attachment bracket?
Is there a reason why you prefer the bolt heads to the rear? It seems an uncommon orientation.​

Below is posted my control rod ends, with large washers to prevent a failed spherical eye from pulling past the nut.
I think this is a significant safety improvement, and at almost zero cost/weight.

Regards, Kolibri

 

[eddie]

the position of the bolt heads and possible rodend failure are really something I have never considered as a safety issue.

I bought the motorcycle dampers on Ebay they are Chinese manufactured,however I bought these from a company in L.A..

the dampners would possibly seize if there was debris inside of the cylinders I don't believe could happen,the only thing that could

happen in my opinion would be the fluid leaking out of the dampners failing to reduce vibration.

The attachment bracket is a L shaped piece of tempered aluminum that is actually attached to the top of the bracket that

the mtr mount rods are attached to,the little bolt you see in the upper middle of that piece is there to a prevent a slight vibration.

The dampners will stiffen the stick movement,which I like as it keeps everything nice and smooth,If need be the stick can be moved

at a rapid rate if necessary. Its suprising how little the stick is actually moved during normal control and even steep turns.

Those are good questions Kolibri,your eye for details is very good.

 

[Kolibri]

Thanks, eddie.
I'm still keen to learn the part # and web links to your dampeners.
Your info so far is interesting, but not quite actionable . . .

 

[eddie]

Kolibri,sorry I don't have any part numbers I don't really keep paperwork. Just go to Ebay and look up

motorcycle dampners, the ones I bought are very common and are being sold by different companys,I just looked until I found a company in the USA

 

[Kolibri]

more from my "eye for details" --

The nuts appear to be shear vs. tensile nuts. Did you intend that?

Also, with their unique shape and goldish color those push tube rod ends very much look like RAF's OEM parts. Are they?

May I suggest that any OEM rod ends be immediately replaced with Heim or Aurora parts, along with large washers (to prevent an eye pulling through)
and tensile nuts (I use nyloc/castellating, but not overly torqued. just enough to remove play).

Also, it would seem wise to very carefully inspect your aluminum scissors for any scoring/stress risers from previous installations.
These scissors are flight critical parts, and if either of them let go in flight, the gyro will become almost instantly unflyable from an uncontrollable rotorhead.

Finally, please remove your mast/scissors bolt for inspection, as your nut-to-front installation (for easier periodic lubrication, I get it) allows for much galling just behind the threads (vs. behind the bolt head, as per RAF's orientation in their Construction Manual). Also, installing that bolt with the head up front provides some security against it working itself out if the nut or threads eve r failed.

You seem to have a shear nut there also, which I think highly inadvisable given the mast movement forces applied to that bolt. Your current bolt looks long enough for a proper tensile nut.

Regards, Kolibri

 

[Kolibri]

For comparison, here's one of my old RAF OEM control rod ends, shortly after my purchase.
They are AISI 1112b Grade Zero low-carbon Chinese junk. They've failed in flight, and killed people.
Heim HM-6M rod ends replacements save lives.