Raf rotor blade cracks!!!!!!!!!!

Blending question

Blending question

Jim,

Thanks so much for your suggestions. If you are not carefull you can damage the ends of the bar real easy. A padded case for storage is a good idea when not in use.

My hub bar has a non directional finish on all the surfaces. I would not call is polishing but some kind of surface treatment. Maybe a blasted walnut finish. I do not know.

What are your ideas of polishing the critical areas to a smooth/mirror finish ?

Bead blasting with glass or iron shot ?

Or would you just suggest a mild flap wheel treatment to all the radii ?

Lastly I went thru the entire batch of paperwork to see if RAF lists COMPLETE torque specs. The only specs I saw were for the small 1/4" pitch adj blocks of
70 in lbs
120 in lbs for the strap to blade hwd.

200 Ft lbs for the main bolt. Which I do not know if they list in the papers, I talked to a tech at RAF....

What are your recommendations for the teeter bolt of

AN6 - 3/8"

and

AN5 - 5/16 Bolts strap to bar ?

Lastly my straps seem to have been generously radii'd on the ends prior to plating.

Jonathan
 
polishing

polishing

Jonathan,

The only answer I can give at this time to your questions are:

We have no problem with the RAF surface finish on this part.

When blending, a smooth finish is preferable. no gouges, pits, checks, notches remaining.

Sorry to not be more explicit.

Jim
 
All the Raf literature that I was dealing with a few years ago said, "DO NOT REMOVE or TIGHTEN/ADJUST THE 1" BOLT". That is why there would be no specs in the Raf manuals for this bolt.

Aussie Paul. :)
 
Doug Riley said:
Very roughly, 6061-T6's strength plummets to a third of its one-time strength at 100,000,000 cycles. A hundred million sounds like a lot, but at 2/rev on a 350 RPM rotor, it's only 238 hours.
Click to expand...

Umm... I get something different:

2 (cycles/rev)* 350 (rev/min) * 238 (hours) * 60 (min/hour) = ~10,000,000 cycles
100,000,000 / (2 * 350 * 60) = ~ 2,380 hours

But perhaps more constructively, is that degradation to 1/3rd strength roughly linear?

regards,
John
 
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Ken that was not even funny.

I remember reading that in a few different places at the time of the award Let me get this straight....The folks at RAF, figured they would make a quick buck on the market with some gee wiz looks cool on paper "safety" thing and never even put the material in the environment in which it would be working ? You have it correct.

Tell me more about this ignition system thing. How long ago was this. I bought a used raf system off of the conference here. (Russ Kempka) Guy says its only got 20 hours on it. How many hours were they failing ? It is supposdly a new system. Maybe I will use it for a wall ornament.

I'd say it was 4 or 5 years ago. Mine failed at around 80 hours. I was over a good-sized lake when it coughed a couple times. I made it the 5 miles to where I was going. I called Peter from there and told him what happened. He said he'd send me a new one at no cost. I asked him to repeat that as I already had an ElectroAir ignition in my hangar to install as a back-up and wasn't going to pay anything for another RAF one. I'd put the money toward a 2nd ElectroAir...which I eventually did.

He sent it in a few days, I installed it and flew her back home. About 2 weeks later, I get a bill for $100 for the ignition "repair." I called Linda and told her Peter said there would be no charge. She said she'd check with Peter and be right back. She came back in a couple minutes and told me that Peter told her that he never said that. A bold-faced lie. I don't know at what point the other 30+ failed. Probably all over the spectrum. By the time RAF admitted the problem (how could they ignore it any longer?), they blamed it on their diode supplier.

I'd get at least one (two are better) ElectroAir system and run a separate tach for each ignition, so you know at a glance that one failed. I don't believe in running 2 ignition systems into one tach. And I strongly suggest running both simultaneously always. If the one your using craps out, you won't have time to realize what happened, switch on the other ignition, attempt a restart and all the while checking the wind and setting up for a safe landing. Running one is foolish unless you fly 5,000 ft. AGL. Same goes for dual fuel pumps. If you run 2 fuel pumps and 2 ignitions constantly, if your engine stops, you only have one chore to concentrate on....picking a spot and trying to hit it safely. No distractions from clicking switches and pressing starter buttons.


I am curious how many sets of blades you think are flying out there ?

I have no idea....probably upwards of 500.

Lastly, if RAF and the crew are as bad as everyone here has been saying
WHY ? are they still allowed to do business ? Is canada that business friendly that they will turn a blind eye to what amounts to criminal activity ?

Because it's "experimental." My DAR told me if I stuck an engine and prop on a big cardboard box, he'd have to sign it off."

Jonathan
 
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Jim Mayfield.....I just want to thank you for your excellent comments on this rotor blade topic. The mannerism in which you conduct your posts speaks so highly of you. With guys like you behind SparrowHawk...it has to be a winning combination.

I was considering a nice set of Sportcopter blades...but they were spoken for...at least I thought so. This thread caused me to immediately search them out and finding out they were still for sale...so maybe it was a knee jerk reaction on my part...I dont know...but I bought them. I know even if my blades are ok...and they probably are with a more rigid inspection schedule...I just know I will enjoy the rest of my RAF so much more not wondering whats going on up there with that hub bar.

My RAF blades did already have the radius treatment on the plates...the ends are not digging in at all...and they are away from the angle change area.

Even though I really liked my RAF blades....my honest opinion is that the Sportcopters have several advantages...and they do have a most impressive track record.

Stan
 
RAF time change on blades and hubs

RAF time change on blades and hubs

I found the product notice on the hub and blades. The cracked hub bar experienced by Paul is not the first. In Aug 11, 1994 a notice went out asking all hub bars to be returned for inspection. 2 incidences were reported on bars with excess of 200 hrs. If cracks were found no flights were to be taken(dah)
A notice sent out on june 18 2001 suggests life xpendency to be 1925 launches or life expendency of 1000 hrs based on their research done by Dynamic solutions, Vib Tech Int. as well as Jim Butler.Their claim is is that the bar is 6061 aluminum and is the most substantial in the market place. But it is sugested to time change the bar and blades at 500 hrs. It suggests that vibration and and how it is stored and type of terrain flown from and landings all play a part in the integrety of the parts and it is impossible for RAF to give an exact life expendency. So they feel 500 hrs is the safe number. With the hub bar in question,I would be curious as to how the blades and hubbar were used as far as weight they carried , type of terrain flown off of, support of blades when not in use, and how many hours on the blades and bar.
 
Correct me if I'm wrong but these things go for about $4,000.00 with the bar right? and if you do, lets say, 5 hours a week thats 4 g's every 2 years? Something wrong about that...for non moving parts-(they really are if you think about it) No friction or anything like an engine. The life expectancy for the sportcopters is supposed to be the life of the craft.
 
MORE TO THE story..

MORE TO THE story..

You know I should open up a 1 900 psychic line sometimes.

Emailed RAF. Got a very interesting response. According to Don he says, I am refering to "derek" who ever this is,

Owner was the 3rd person or 3rd owner. How accurate do you think the time was kept ? 500 hours or 1500 hours ?

2. This is a biggie. Blades were trashed on 2nd owners machine. If this is infact true then we all should not be having this discussion at all. If you are that stupid that you would use any control system parts from a thrashed machine, esp a hub bar then I got a bridge, a peanut machine and those new atm / video machines to sell you !

Ask Maxie if he will sell you his crashed hub bar from his new raf blades ?

3. Inspections were never done, blades were left on the machine for transport.

This is at least what I have been told.

raf blades cost 2500.00 approx. usd

Jonathan
 
The story ?

The story ?

Hi Jonathan
Your referring to *****s blades did you know that he is a third owner
and that the previous owner had rolled his aircraft . And none of the 100 hour
inspections we're done. And the blades had just over 500 hours.
product notice # 31 covers part of the 100 hour inspection.
ROTARY AIR FORCE REF:C/PRONOT.RAF-31

PRODUCT NOTICE RAF 2000 GYROPLANE


19 December 2000


NO. 31: •ROTOR BLADE STORAGE and TRANSPORTATION


CAUTION/WARNING to all RAF 2000 GYROPLANE OWNERS.


Rotor blades are precision components the handling of which require care, attention, and common sense.


•ROTOR BLADE STORAGE and TRANSPORTATION: It is imperative to store the rotor blades properly when the aircraft is not in use for extended periods of time. RAF reminds owners that rotor blades left on the aircraft with no support for an extended period of time can lead to distortion, bending, and cracks. Rotor blades should be supported when not in frequent use.


Care must be taken during transportation of the rotor blades. RAF reminds owners that transporting the gyroplane, with the rotor blades left on the aircraft is not recommended.


When transporting the rotor blades on a rack, if the hub bar is left on one of the rotor blades, ensure that the hub bar is supported so that undue stress is NOT put on the hub bar winglet, tension straps, or root end of the rotor blade.


It has come to RAF's attention that some owners are "flinging" the rotor blades as part of the set-up of the rotor blades. This practice MUST CEASE as this will put stress marks, scratches or could elongate the holes in the hub bar winglets which may lead to the winglets cracking.


Continue with pre-flight and post-flight inspections as laid out in the Flight Manual and Operating Limitations Manual and RAF 2000 Maintenance Schedule. See Section IV, 8, 9.


Add to the 100 hour inspection the following: Remove the rotor blades from the hub bar winglets and check for scratches, stress risers, or elongation of the holes in the winglets every 100 hours of operation. Repair or replace the winglets as required.


•NOTE: AIRCRAFT PRODUCT NOTICE NO. 31 •ROTOR BLADE STORAGE and TRANSPORTATION, Addition to 100 hour inspection. CAUTION/WARNING to all RAF 2000 GYROPLANE OWNERS
 
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Aussie Paul: Are you in a position to get hold of (and post) the operator's own version of events?

cheers,
John
 
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I climbed up this afternoon and took a hard look at my hubbar and blades. I always give them a once over but not the thorough look like today. Not a mark and not a flaw. I just turned 82 hrs on the blades. I always support them when in the hanger by a simple rope system. The posted notam from RAF makes perfect sence. Take care of your wings.I then went flying. They are super blades with lots of lift and lots of stored energy when landing. The blades make even me look like I know what I am doing every time I land. I really love the wap wap sound!In Pa, the leaves are at full fall foliage. I will take some pictures this weekend and post. Simply put,God's handywork at it's best.Back to the subject of rotor hub/blades. Mine fly great. Chris wants to fly my RAF's compared to his sport copter blades. I would like to try to feel the difference if any. Stan, as miticulas as you are, I think you jumped to quickly at the new's of a faulty hub.I would find it hard to believe you would'nt catch a problem before it got past the point of no return. Who knows how long the pilot was flying his blades or what type of care or abuse they had.Still, It is always nice to have a second set of blades. I have a 24th generation set of new RAF's under the truck in the garage and I have not even tried them on the older RAF I own. The reason being, I am happy with the smoothness of the 3 year olds.Hope to get the data on how the hubbar in question was used .
 
Larry: There was enough information out there to make me feel uneasy. I am anticipating more efficient flying..smoother flying..and safer flying. I probably would have had no problems with my RAF blades...but one thing is for certain...they need to be watched closer.



Stan
 
Larry :

Why don't you ask Duane Hunn, he is an RAF Rep. and he had one of his own hub bars crack so he would have first hand knowledge.

Let us know what he says.

Chuck E.
 
Why is RAF into their 24th generation of blades? Can't they get it right? That's 24 fixes in a relatively short time for an aircraft component. I know how one "generation" came into existence. An RAF owner had at least 2 brand new sets of blades delivered with cracks already in them. He phoned RAF, and one of the female employees there (not sure if it was Linda), told him, "Oh, we had a new guy making the blades and he wasn't sure of the process." This is an actual quote from RAF. I guess the next generation blades were after he was taught how to make them correctly.

You guys that are bull-shitting yourself that you're dealing with a quality design, product and company are just whistling while walking past the graveyard. It doesn't help. There is enough evidence that the blades have had numerous cracking problems and uneven insides and numerous hub-bars have cracked. It has been clearly pointed out of the ignorant design parameters of the hub-bars.....no radii, cross-cut of the grain and ramping down from larger diameter to smaller one. The fact that they tell you to never check the main bolt should tell you something too. I would believe anything that came out of Don's mouth (A proven liar. Remember the "genuine Subaru parts" contradictions?), as much as I'd believe that boiling dog shit will turn it into gold.
 
Ken don't you find it strange that the only " supporters" for RAF happen to be also owners or users of their Products?
 
Do you like eggs with your bacon?

Do you like eggs with your bacon?

Gentlemen,

I have followed this thread with a great deal of interest, so much so that I've taken the opportunity to reread the entire postings again tonight. It does seem to me that we are in great danger of being accused of firing from the hip at moving shadows.

A number of salient points have been posted regarding the need for inspecting hub bars, potential design flaws, the use of dyes to check for cracks, the behaviour of aluminium , dual ignitions etc. However there is also a number of other posts presented, which are charged with emotion, which in hindsight taints their accuracy and as a direct linkage their usefulness to us in this sport.

The origional post by Paul, of a RAF hub bar cracking, needs to be carefully examined. Its a shame we don't factually know the history of this hubbar, for its from this that we could gain a true understanding of what caused the cracks. Is it simply a design fault, or a behaviour of the metal problem? Could it be that the hubbar shows cracks because of previous mishaps or improper storage and handling, or is it a combination of some or all of the above?

I believe that Mr Mayfield's post brought a great deal of sensibility back into this discussion. Let us follow his example. I am in no way supporting or endorsing RAF, their products or the behaviour of persons connected with this company. This thread was in great danger of falling into a lynch mob mentallity. Lets not make this forum, infamous on this point.

So gentlemen, if we are going to venture forth in the middle of the night to investigate some suspisious activity in the fowlyard, lets not wake up next morning to find we've shot all the chooks just because we thought we saw some movement in the shadows.

For those of you who are inclined to shoot first and ask questions later, well now's a good time to think of a reason to tell the wife, "I don't understand why the chooks aren't laying".

Ted
 
Ted Eggleston said:
The origional post by Paul, of a RAF hub bar cracking, needs to be carefully examined. Its a shame we don't factually know the history of this hubbar, for its from this that we could gain a true understanding of what caused the cracks. Is it simply a design fault, or a behaviour of the metal problem? Could it be that the hubbar shows cracks because of previous mishaps or improper storage and handling, or is it a combination of some or all of the above?
Click to expand...

ted excuse my intrusion, and i think you have a lot os wisdom, i am more a mad dog, probably due to my young age and the will to participate positively to some debates..

but , not to counter you, i think the statements above should be thought while designing BEFORE releasing something to the public, they look like prototyping work in a labo, but here the white rabbits are living persons... that s not the work of drivers to tell FORD about design problems after an accident.. and less again to find their own solutions, even if nothing can be perfect, agreed.

just a funny story about quality i ve been told by a FIAT people, (i worked in automotive parts sales) :

fiat, once upon the time, asked Mitsubushi to manufacture a pre-serie of turbochargers... they asked for a maxima of 5 % of unperfection, so ordered a batch of 100 turbo....
later...
they recieved a crate with the stuff and the japanes eng told them... "here are the 105 turbo chargers you ordered... 100 and the 5 % of unperfect you ordered, so we put them in a separate crate but we dont know what you may do whith them...."

cheers
 
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