Spherical rod ends in the rotor control system.

Brian Its because Kolibri's RAF was a corroded out rust bucket when he bought it, he got screwed his rodends were so corroded he had to replaced them

and just about everything else because of corrosion. And now for some reason he thinks he is the RAF safety Guru. My RAF is in very good condition as are the

other ones I have seen ..There is really nothing to his rants that support that we are gong to die because we don't listen to him.

he is the know-it-all about the RAF and now all Gyros in general,


.
 
I don't mean to add fuel to a heated subject, but for all the ranting about inferior OEM parts, why are so many of them still on the ship? No disrespect intended, I'm simply curious.
None taken, Brian, and it's a fair question.
Regarding my RAF's rod ends (none of which were "
so corroded"), I at once replaced what were imperative back in 2015: the control system rod ends.
I next replaced what was highly prudent: the alternator mounts (adding a long single bolt).
Finally, I will, as earlier described, replace what I've concluded are generically prudent (though not mentioned by other owners).
Few RAF owners have done the first two steps, and none that I know of the last step.


And, btw, eddie has never seen my RAF, else he'd know that it was never a "corroded out rust bucket".
I wouldn't have purchased any gyro in such condition. It was shiny and rust-free. It's even better now, because I've cared to make it so.



________
There is really nothing to his rants that support that we are gong to die because we don't listen to him.
eddie, my sincere offer that I posted to buy you a set of Heims for your RAF is rescinded. (I now recall the excellent advice of Matthew 7:6.)
Well, I hope that you don't auger in, but if you do at least the investigators will have a good preliminary theory why.


________
Vance, my forum name is Kolibri. It is proper Netiquette to use only to that.
This is what I practice, and if a Member uses the lowercase for his name (such as dunc or eddie), that's what I use.
My personal info is not available to non-Member lurkers, yet you post it nonetheless. I believe this is explicitly forbidden by Forum rules.
Please cease and desist. Thank you.



. . . I am describing one way to break . . .
. . . is usually from . . .
Ah, now you're properly implying other possible causes. You weren't previously.


It is my observation that when a spherical rod end breaks from poor quality or overloads the failure is usually in the area of the ball.
It is my observation that when a spherical rod end breaks in the area of the threads it is usually from misalignment.
Perhaps, but neither seem to be the general observation of many RAF owners regarding their old rod ends.
They can and do break elsewhere and elsewhy, as I've quoted their posts from 2004.


______
There are three levels of design/parts quality:



1) top-notch, which have no record of failure, nor seem ever likely to fail

2) mid-range (i.e., less than top-notch, but better than atrocious) which occasionally fails

3) atrocious


The atrocious rarely make it on even E-AB kits, because it fails so quickly and so often.

The top-notch is also rarely seen, because of weight or expense or inconvenience or wait factor. An example of top-notch that comes to mind
are the rod ends which Sport Copter uses in their gimbal arm: the Aurora HXAM-6T high misalignment (22°) rod ends. (Theirs are specially made
with 0.25" ball I.D., eliminating the need for a weaker ⅜" Orlite bushing.) With a body of heat treated 4340 steel, this is hell-for-stout at 11,781 lbs
ultimate radial static load capacity. Self-lubricating with a PTFE liner. Instead of the industry-common 3/8 shank, it has a 7/16. (The push tubes are
much thicker than industry norm, to reduce buckling.) Everything thing about the part is top-notch. Its failure is nearly inconceivable.

However, what we generally see in E-AB is the mid-range quality design and parts. Such is often cheaper, lighter weight, and off-the-shelf.
The spectrum is quite wide, from bordering atrocious to approaching top-notch. The worrisome thing about mid-range is that it usually works
sufficiently well not to cause alarm. The odd failure or two is generally written off as a fluke, or pilot error.

In my view, aviation design and parts should be seen as "guilty until proven innocent".
That is, by the way, the mindset of pre-flight and annual inspections.
One assumes that something must be loose, cracked, bent, broken, corroded, chafing, weak, plugged up, backwards, or missing.

In my shooting courses I mention to students that if I notice something odd in the tactical world three times, I "log it in" as worthy of discussion.
(An example would be a certain handgun firing off an ejected live round, or a particular odd feeding failure in an AR such as base-over-bolt
with lacquered steel case imported ammo).



Once is incidence.
Twice is coincidence.
Thrice is enemy action.

There have certainly been enough RAF rod end failures by now to justify not only warning but outright preemptive replacement.
I would classify the old RAF OEM rod ends (AISI 1112b <Grade 0) as within mid-range but nearly atrocious. Many people concur.
They needn't be bent from excessive misalignment to crack; they can crack from normal tightening/loosening, from normal use, and from normal vibration.

And, because of the nature of rod ends in general, they are subject to bending loads even within their range of misalignment.
(axial load + eye height = bending load). Now, this bending load must be within limits, of course, but it still exists.

Thus, there is no reasonable justification of those RAF rod ends.
They are not "innocent until proven guilty" on a case-by-case basis.
Rather, they are definitely suspect and untrustworthy.

It is wrong to defend them by claiming that they "generally" work because that will provide sufficient rationale for the cheap and lazy owners not to replace them.
This is a disservice to aviation safety, and conduct unbecoming.

I've attached my 2015 pdf (recently revised) about RAF rod end choices.
Those interested in upgraded their parts to aviation-quality are welcome to post or PM me with any questions.

Safe flying, Kolibri
 

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Kolibri... I owned an RAF and changed out its rodends, and also used a bolt on the alternator. Do you have the updated nosewheel part? Mine failed on take off with my dad onboard and the nosewheel collapsed and the nose of the cabin dropped to the grinding us to a halt. I was staring down at the runway holding backstick till the blades stopped. It could have been ugly, but ended up with the only scratch I ever put on a gyro , and I had it fixed and flying in 3 hours. I had procrastinated for a year with that new part ....not installing it like I should have. Several RAF's have been totalled from this one defective part.
 
Kolibri;n1130392 said:
None taken, Brian, and it's a fair question.
Regarding my RAF's rod ends (none of which were "
so corroded"), I at once replaced what were imperative back in 2015: the control system rod ends.
I next replaced what was highly prudent: the alternator mounts (adding a long single bolt).
Finally, I will, as earlier described, replace what I've concluded are generically prudent (though not mentioned by other owners).
Few RAF owners have done the first two steps, and none that I know of the last step.


And, btw, eddie has never seen my RAF, else he'd know that it was never a "corroded out rust bucket".
I wouldn't have purchased any gyro in such condition. It was shiny and rust-free. It's even better now, because I've cared to make it so.



________

eddie, my sincere offer that I posted to buy you a set of Heims for your RAF is rescinded. (I now recall the excellent advice of Matthew 7:6.)
Well, I hope that you don't auger in, but if you do at least the investigators will have a good preliminary theory why.


________
Vance, my forum name is Kolibri. It is proper Netiquette to use only to that.
This is what I practice, and if a Member uses the lowercase for his name (such as dunc or eddie), that's what I use.
My personal info is not available to non-Member lurkers, yet you post it nonetheless. I believe this is explicitly forbidden by Forum rules.
Please cease and desist. Thank you.



Ah, now you're properly implying other possible causes. You weren't previously.


Perhaps, but neither seem to be the general observation of many RAF owners regarding their old rod ends.
They can and do break elsewhere and elsewhy, as I've quoted their posts from 2004.


______
There are three levels of design/parts quality:
1) top-notch, which have no record of failure, nor seem ever likely to fail

2) mid-range (i.e., less than top-notch, but better than atrocious) which occasionally fails

3) atrocious




The atrocious rarely make it on even E-AB kits, because it fails so quickly and so often.

The top-notch is also rarely seen, because of weight or expense or inconvenience or wait factor. An example of top-notch that comes to mind
are the rod ends which Sport Copter uses in their gimbal arm: the Aurora HXAM-6T high misalignment (22°) rod ends. (Theirs are specially made
with 0.25" ball I.D., eliminating the need for a weaker ⅜" Orlite bushing.) With a body of heat treated 4340 steel, this is hell-for-stout at 11,781 lbs
ultimate radial static load capacity. Self-lubricating with a PTFE liner. Instead of the industry-common 3/8 shank, it has a 7/16. (The push tubes are
much thicker than industry norm, to reduce buckling.) Everything thing about the part is top-notch. Its failure is nearly inconceivable.

However, what we generally see in E-AB is the mid-range quality design and parts. Such is often cheaper, lighter weight, and off-the-shelf.
The spectrum is quite wide, from bordering atrocious to approaching top-notch. The worrisome thing about mid-range is that it usually works
sufficiently well not to cause alarm. The odd failure or two is generally written off as a fluke, or pilot error.

In my view, aviation design and parts should be seen as "guilty until proven innocent".
That is, by the way, the mindset of pre-flight and annual inspections.
One assumes that something must be loose, cracked, bent, broken, corroded, chafing, weak, plugged up, backwards, or missing.

In my shooting courses I mention to students that if I notice something odd in the tactical world three times, I "log it in" as worthy of discussion.
(An example would be a certain handgun firing off an ejected live round, or a particular odd feeding failure in an AR such as base-over-bolt
with lacquered steel case imported ammo).
Once is incidence.
Twice is coincidence.
Thrice is enemy action.



There have certainly been enough RAF rod end failures by now to justify not only warning but outright preemptive replacement.
I would classify the old RAF OEM rod ends (AISI 1112b <Grade 0) as within mid-range but nearly atrocious. Many people concur.
They needn't be bent from excessive misalignment to crack; they can crack from normal tightening/loosening, from normal use, and from normal vibration.

And, because of the nature of rod ends in general, they are subject to bending loads even within their range of misalignment.
(axial load + eye height = bending load). Now, this bending load must be within limits, of course, but it still exists.

Thus, there is no reasonable justification of those RAF rod ends.
They are not "innocent until proven guilty" on a case-by-case basis.
Rather, they are definitely suspect and untrustworthy.

It is wrong to defend them by claiming that they "generally" work because that will provide sufficient rationale for the cheap and lazy owners not to replace them.
This is a disservice to aviation safety, and conduct unbecoming.

I've attached my 2015 pdf (recently revised) about RAF rod end choices.
Those interested in upgraded their parts to aviation-quality are welcome to post or PM me with any questions.

Safe flying, Kolibri

This is a simple thread with a simple point.

Don't put spherical rod ends in bending by adjusting them to where they exceed their maximum misalignment and a simple procedure for checking them during pre-flight.

I often see spherical rod ends in bending and it is easy to check in pre-flight.

I recently broke a quality spherical rod end by exceeding the maximum misalignment.

The thread is about all gyroplanes with spherical rod ends.

Kolibri went off on one of his toxic RAF rants misinterpreting information and condemning me for things he imagined I implied.

It is my observation people like to blame somebody else for their mistakes.

I find I learn more by recognizing my part in things that don't work out.

From my perspective Kolibri is operating on an emotional level. I find his posts reminiscent of religious histrionics.

I have never cared for screen names and prefer to address people by their given names. I am sorry if that violates some code on conduct I was not aware of and do not subscribe to.
 
"If you have an RAF with the original low-grade control rod ends, you'd be very wise to replace them with better parts."

Vance, you still haven't said this, and apparently cannot.
Noted. I'll move on.



________
Kolibri... I owned an RAF and changed out its rodends, and also used a bolt on the alternator. Do you have the updated nosewheel part? Mine failed on take off with my dad onboard and the nosewheel collapsed and the nose of the cabin dropped to the grinding us to a halt. I was staring down at the runway holding backstick till the blades stopped. It could have been ugly, but ended up with the only scratch I ever put on a gyro , and I had it fixed and flying in 3 hours. I had procrastinated for a year with that new part ....not installing it like I should have. Several RAF's have been totalled from this one defective part.
Stan, thanks for mentioning the NW spindle.
Yes, I did change mine out, and your story helped compelled me to do so.
I'm glad that you and your dad weren't injured.

Your "RAF spindle" thread of
06-02-2005 is in the RAF board, thanks for that.

If a magnet won't attract to the circular NW spindle flange, then it's the original aluminum.
The steel shaft is prone to breaking at the roll pin.

Regards, Kolibri
 
No Title

If you look at the way I design my cross bar, you will notice the rod ends are ergonomic to the movement and less bending stress to the rod ends.
Same with my idler arms and cyclic fork.
 

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That is a very clean set up Jake.

In my experience if the control rods are adjusted correctly on most control systems there is not much stress.

The challenge I am describing happens when they are not adjusted correctly or they are not the correct spherical rod ends for the application and the maximum misalignment is exceeded.
 
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I have seen several failed control rod ends in RAFs.

All but one showed evidence of bending and in my opinion it was not due to the quality of the rod ends, the odd one appeared to have had the jam nut over torqued. The application did not call for misalignment capability so bending was unlikley.

I have not seen an RAF rod end fail at the eye in flight. I have seen some fail at the eye from over stress after an accident.

As I have written previously if I had an RAF I would probably replace the rod ends because I like quality hardware.

I do not have enough firsthand information to condemn all RAF spherical rod ends and do not claim to be an expert on anything to do with RAFs.
 
If you look at the way I design my cross bar, you will notice the rod ends are ergonomic to the movement and less bending stress to the rod ends.
Same with my idler arms and cyclic fork.
That looks like good engineering, gyrojake.
Big, fat, strong push tubes, too.
Which rod ends did you go with?


_________
I do not have enough firsthand information to condemn all RAF spherical rod ends . . .
We differ on how to view them.
To me, there is (since 2004) plenty of evidence to condemn them all, primarily because if any one of them breaks, a crash will ensue (likely fatal).
While most of them have held up, one can never know if a particularly bad part is in one's machine.
Why take such a demonstrated chance with $2 rod ends? It's nuts to do so.

Regards, Kolibri
 
No Title

This thread is about putting spherical rod ends used in the control system of gyroplanes in bending and how to check for binding during preflight.

I have seen quality spherical rod ends break from being in bending.

I have seen people blame a spherical rod end failure on the rod ends when in my opinion it broke because it was in bending.

When I last replaced the spherical rod ends on The Predator it cost me somewhere north of $600 for the ten rod ends used in the control system.

Something I ponder is; once a spherical rod end has been put in bending it may not show the damage and yet it may have a crack that is very difficult to see and be working up to failing. In my opinion it is no longer airworthy.

In my opinion this rod end broke because it was put in bending. It appears to me to be a quality part. I do not have the paperwork.
 

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Kolibri;n1130667 said:
That looks like good engineering, gyrojake.
Big, fat, strong push tubes, too.
Which rod ends did you go with?


_________

We differ on how to view them.
To me, there is (since 2004) plenty of evidence to condemn them all, primarily because if any one of them breaks, a crash will ensue (likely fatal).
While most of them have held up, one can never know if a particularly bad part is in one's machine.
Why take such a demonstrated chance with $2 rod ends? It's nuts to do so.

Regards, Kolibri

I use a 3/8 x 3/8 x 1 1/2" long $3.85 rod end that outperforms the $50 ones.
I also use 1/8" wall 6061 for my push rods.
The fact that my ends are always in compression and have no misalignment issues in any part of the cycle gives me confidence.
I've used these on my two seater with 2500 hours.
Junk-N-Stuff, 530 hours, and 17 other machines in the last 26 years with no issues.
Alignment and function with no binding are the attributes you want in a control system.
 
Thanks for the input Gyrojake,its nice to know there are a few people who truly understand now things work,vance being another one

who understands. the most expensive is not always the fix its knowing how to use what you have
 
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I have a friend with an RAF that felt replacing the "junk RAF rod ends" with aircraft quality spherical rod ends was critical for safety.

After replacing all the rod ends in his RAF rotor control system on what may have been his third takeoff he broke one of his new aircraft quality spherical rod ends during takeoff resulting in a roll over with no injuries and substantial damage to the aircraft.

He showed me the RAF spherical rod end that he replaced and it showed signs of bending. In my opinion if it had been an aviation quality spherical rod end it would have broken before bending that much. He has about 150 hours on the "RAF junk" rod ends.

In his opinion the bending was a sign of "junk spherical rod ends" and his aerospace rod ends would never bend with so little force.

This was many years ago and as far as I know the wreckage still sits in his hangar. The last time I talked to him he still felt it was a defective aircraft quality spherical rod end that broke and there was nothing wrong with his instillation or adjustment. He feels the whole RAF rotor control system is a dangerous design.

When I saw my friend recently he reminded to replace my spherical rod ends often on The Predator and was amazed I had not crashed her yet.
'
He seldom misses an opportunity to tell people how dangerous all gyroplanes are and RAF's in particular.

I agree that gyroplanes are dangerous.

I agree that good spherical rod ends in the control system have value.

I suspect Jake's rod ends are good quality despite the reasonable price because he pays attention to every detail.

Proper adjustment of the rotor control system and a good preflight are an important part of mitigating the risk.
 
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This is where I buy my rod ends, they have it all at a very competitive price.
 
Gyrojake thanks for the rodend site,there stuff looks really good.
 
I use a 3/8 x 3/8 x 1 1/2" long $3.85 rod end that outperforms the $50 ones.
gyrojake, exactly what about that $3.85 part "outperforms" $50 Heims or Auroras?


I agree that good spherical rod ends in the control system have value.
Oh, but not too good (i.e., aircraft quality) else they'll likely break before bending!
Vance, perhaps you should name the brand of such "Goldilocks" rods ends.



Gyrojake thanks for the rodend site,there stuff looks really good.
eddie, why even look there, as you're not going to change your original rod ends anyway, not even at those prices.



Regards, Kolibri
 
I feel control rod failure is an important subject that some people will never grasp and nothing to joke or troll about.

It is my observation that my friend with the RAF blamed the "junk RAF rod ends" for the failure when in my opinion any rod end would have failed because the maximum misalignment was exceeded and the threaded portion was placed in bending. His opinion does not mean that RAF rod ends are junk and will fail.

Most of the aircraft grade spherical rod ends I am familiar with are softer than the same companies maximum strength spherical rod ends just as NAS bolts are softer than grade eight bolts.

All but one of the spherical rod ends I have seen broken at the threads in my opinion broke from bending. In my opinion that one broke from over torque on the jam nut.
 
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gyrojake, exactly what about that $3.85 part "outperforms" $50 Heims or Auroras?

First, they are made of quality material that has to take the beating of sprint cars and off road front end abuse.
They do not have a plastic lined race, nor do they have a pressed insert.
The lip clearance is very tight but still free to move which lets the lip clean dirt and grime from the ball.
Abrasive materials can loosen the ball and cause play, which will cause a hammering of the lip and oversize the inner race.
The head is also narrow and allows more movement before binding from misalignment.
They forge the outside race to match the ball so it is like a one piece construction.
The threads seem to be tighter than others I've tried and I like that point very much.
I am not saying they are the best thing to use on your machine, or any other, I like them and have performed well for me over the years.
I build my machines to be economical, rugged, and functional, after all, I'm gonna fly it and I love me more than I like anything else.
Since I am uneducated, a quality component can make up for my ignorance.
 
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gyrojake;n1130914 said:
gyrojake, exactly what about that $3.85 part "outperforms" $50 Heims or Auroras?

First, they are made of quality material that has to take the beating of sprint cars and off road front end abuse.
They do not have a plastic lined race, nor do they have a pressed insert.
The lip clearance is very tight but still free to move which lets the lip clean dirt and grime from the ball.
Abrasive materials can loosen the ball and cause play, which will cause a hammering of the lip and oversize the inner race.
The head is also narrow and allows more movement before binding from misalignment.
They forge the outside race to match the ball so it is like a one piece construction.
The threads seem to be tighter than others I've tried and I like that point very much.
I am not saying they are the best thing to use on your machine, or any other, I like them and have performed well for me over the years.
I build my machines to be economical, rugged, and functional, after all, I'm gonna fly it and I love me more than I like anything else.
Since I am uneducated, quality component make up for my ignorance.
Says one of our residence geniuses. Now I even understand. The guy can do anything he tries at the highest levels and knows his stuff.
 
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