Warranties / Guarantees

[tyc]

I've recently begun to explore the world of gyrocopters and as one with experience in the Brantly B2 series, their 305 machines (first helicopter I ever flew in) as well as the Bell 47 and Hughes 269-B, I have to ask, when acquiring blades for a gyro, what kind of warranties and/or guarantees come with these gyro blades being made today? As is the case with most (but not all) helicopters, is there a limited number of hours for these blades intented for gyrocopters?

Of the current manufacturers, who offers the best blades?

One individual here has very recently written about the problems he encountered with not one but two sets of blades - all from the same manufacturer - without once naming the manufacturer - and based on a helicopter background on this end I have to ask, just how safe are these blades currently being manufactured for gyrocopter use; yes, I've noted the comment in another forum regarding one individual employing run-out Hughes 269 blades on his gyro!

tyc

[GYRO J]

Gyros are mostly homebuilt aircraft I dont know of any warranties or guarantees on any purchased or home fabricated parts Its up to the pilot in cammand

[MikeBoyette]

Hughes blades were used in the 1970's as an alternative to Bensen blades. Chuck Beaty was the one who started that movement. He was able to get about 100 sets from somewhere that were timed out. He figured out that they could be used on a gyro if they were run opposite direction as a Bensen blade. This was due to the twist. They preformed better than stock Bensen's and were much more affordable.
As for today's Blades. My father makes Dragon Wing Rotors. He does not offer any warranties or guarantee. He offers his reputation. He has been maufacturing blades since 1990. He has a good product and many happy customers. The Gyro arena is very small so if you sell a bad product word wiil get out pretty quick and your sales dry up equally as quick. You can check it out for yourself on his web site it's www.rotorflightdynamicsinc.com. Hope this helps.

[twistair]

Mike,

We all know the highest reputation of DW rotors. But the question tyc asked looks to be reasonable. Can you tell us what are (at least estimated) hours for DW after which one should start to think of replacing his rotor? I mean if rotor is operated gently and without any mishaps.

Thank you,

[gyrojake]

Rotordyne gave me all my money back because of manufacture related errors. Dragon wings out perform , Bensen, Rotordyne, Rotorhawks, old Sportcopters before they were painted and Skywheels. I've flown and compared these blades over the years and feel Dragon wings to be MY choice. Price is good compared to the rest.

Since gyros are not powered they are pretty well life time, unless you damage them. I flew my skywheels for more than 10 years. Constent blade flapping is your worst enemy so get lessons and learn blade managment.

[tyc]

... Hughes blades ... Chuck Beaty was the one who started that movement. He was able to get about 100 sets from somewhere that were timed out. He figured out that they could be used on a gyro if they were run opposite direction as a Bensen blade. This was due to the twist.


Did Mr. Beaty ever explain how he determined "that they could be (safely?) used on a gyro if they were run (in the?) opposite direction as a Bensen blade."? I ask this as I tend to view the Huges 269 series as an astounding marvel of aeronautical engineering, while at the same time I am aware as to just how fragile that particular aircraft type is. If you don't understand this, have a look at the list of "time limited" items for the Hughes 269 machines and then compare that list to a comparable list as applicable to the Bell 47 series.

tyc

[MikeBoyette]

Tyc,
He would have to answer that particular question. I am sure that he did the calculations and determined them to be safe. He must have been correct because people flew them for many years. I know one in particular, Charlie Presnell flew them on his serial number 001 KB3 for probably five years. Charlie was a high time helicopter pilot and, would have never flown them if there was even a question of their safety.They did have thing alot of people did not like, that was the need for a pretty good prerotator. I only knew of a couple of people who were able to hand start Hughes blades. Both were very strong men and they still had a hard time.

Alex,
I am not sure what the tbo is on Dragon Wings. I've never asked that question. I know Dad put a tbo on the blades that go on the Mosquito. I am not sure there is one on the gyro blades. Like Jake, I think there isn't one since the rotors are not driven. Next time I see dad I'll ask him.

[Harry_S.]

Mike,

Does your Dad make 30 footers, like for the RAF or other lead sleds? Thank you.


Cheers :)

[Hognose]

Let me explain a bit about what life limits on parts mean.

If there is no life-limit time on the blades, then you're flying them "on condition." With parts subject to fatigue (and aluminium anything is subject to fatigue if loaded) you can either have "safety by inspection" or "safety by replacement."

You use "safety by inspection" (flying "on condition") when (1) you don't know when to expect the part to lose airworthiness due to fatigue AND (2) you can be reasonably confident that you will detect the loss of airworthiness during normal inspections. (Pre-flight, interval, annual, etc).

You use "safety by replacement" when you (1) do know when the parts can be expected to show airworthiness-threatening levels of fatigue OR (2) you cannot determine the airworthiness of the part by normal inspections (in other words, an unairworthy condition can develop in the part before it can be caught).

FARs specify that some manufacturers and operators using some types of certifications must impose and observe life limits. Under FAR 23/25/27 even airframes have life limits. Robinson Helicopter has always placed a firm overhaul life limit on their aircraft. At 2,200 hours (IIRC) it goes back to Robbie or to a factory-approved overhaul station.

Organizations that set safety-by-replacement times (life limits) do it several ways. By testing to destruction, by testing in simulated or actual use cycles, or by developing a statistical database of in-service failures (the hard-headed way). The life limit is set not when the part is expected to fail, but usually at something like where the predicted failure count breaks the 99th percentile -- by which I mean, barely 1% of the parts will have failed by that point.

The downside of safety-by-replacement, then, is that you throw parts out that are three standard deviations away from the median failure service life. In non-stat-speak, you throw away lots of parts that still could have served many hours. The thing is, you don't know which one of a hundred parts you throw away is the one that was getting close to failing. (You err on the side of safety).

I shouldn't wonder that the use of Hughes blades on a 600 lb. MTOW gyro didn't load the blades enough to fatigue them any further. You could take a beam from a highway bridge replaced as unsafe and it could span a creek on your farm for 100 years, no problem. It's not just how long you load the part for, but how MUCH you load it!

To answer the original question, I'm unaware of any warrantees or guarantees on experimental aircraft or rotor blades, but I've heard several stories of makers standing by their work to keep their customers satisfied.

Also, rotor-blade-related mishaps are uncommonly rare. The original Bensen rotorhead, which has been so widely copied and tinkered with, is seriously overbuilt. I can think of three mishaps, though, off the top of my head.

(1) a CFI had an RAF blade/hub-var assembly come apart (it was on a non-RAF gyro). The blade departed from the normal plane of rotation and struck the CFI's student fatally. Another student alleged that that aircraft was not well-maintained.

(2) There was a mishap in Puerto Rico a couple years ago where a set of blades (I will not state the brand because I'm not 100% sure I remember right, and it might have been a plans-built or kit-built blade) slung the D-shaped leading edge weight/reinforcement. The pilot did not survive the loss of RRPM/control and impact with terrain. The blades had not been assembled properly and there was nothing holding that D-section inside the extruded alloy blade. (Normally there would be several bolts or screws, loaded in shear. Centrifugal force puts HEAVY loads on rotor components).

(3) Last summer, a pilot/builder/designer had a rotorhead failure do to improper assembly, also.

cheers

-=K=-

[Master Roda]

Rotordyne gave me all my money back because of manufacture related errors. Dragon wings out perform , Bensen, Rotordyne, Rotorhawks, old Sportcopters before they were painted and Skywheels. I've flown and compared these blades over the years and feel Dragon wings to be MY choice. Price is good compared to the rest.

Since gyros are not powered they are pretty well life time, unless you damage them. I flew my skywheels for more than 10 years. Constent blade flapping is your worst enemy so get lessons and learn blade managment.

So are you saying the NEW Sportcopter blades (painted) are better than the competition?

ALSO, we make 30,31,and 32 foot rotor systems. (for who asked)

I figured I would make mention since no one seems to ever mention SPORT ROTORS.

Jon

[Racer]

When I took a tour of the Air Tractor factory in Olney TX. (They make industrial workhorse planes used for crop dusting and fire fighting applications) they had a hydraulic wing flexer set up that flexed a wing up and down using hydraulic rams running 24/7.
The test they were running at the time was an 80,000 hour test and if the wing passed that test they could give the wings a 20,000 hour lifespan in the actual airplanes.
Basically they only can rate the wings at 25% of what they actually pass in testing.

[MikeBoyette]

Mike,

Does your Dad make 30 footers, like for the RAF or other lead sleds? Thank you.


Cheers :)

Harry,
No he does not. He only makes up to 29 feet. He feels that those bigger machines need at least an 8 in cord. This would require considerable expense to tool for it. He is happy with market share he has. He is more than happy to let Sport Copter and others take the led sled market.

[Harry_S.]

Harry,
No he does not. He only makes up to 29 feet. He feels that those bigger machines need at least an 8 in cord. This would require considerable expense to tool for it. He is happy with market share he has. He is more than happy to let Sport Copter and others take the led sled market.



OK Mike, thank you.

More lead sleds in the near future?? Plan ahheeeaaad?!


Cheers :)

[gyrojake]

So are you saying the NEW Sportcopter blades (painted) are better than the competition?

ALSO, we make 30,31,and 32 foot rotor systems. (for who asked)

I figured I would make mention since no one seems to ever mention SPORT ROTORS.

Jon

No Jon I'm not, because I never flew the new blades. Send me a set of 26' rotors and I'll let you know what I think. All of what I've mentioned was from blades I've paid for totally unsoliceted.

[Hognose]

I figured I would make mention since no one seems to ever mention SPORT ROTORS.

Jon,

I think it was before this forum, on Norm's forum, that Kenny Janulewicz did an A/B test with Sport Rotors and factory RAF blades in what was then a stabbed RAF (he later AAI/Groen'd it). He wound up sticking with the Sport Rotors after that. The test wound up being a pretty good testimonial for your product.

Might be worth digging it out now that Norm's forum is sort of alive again.

cheers

-=K=-

[Harry_S.]

So are you saying the NEW Sportcopter blades (painted) are better than the competition?

ALSO, we make 30,31,and 32 foot rotor systems. (for who asked)

I figured I would make mention since no one seems to ever mention SPORT ROTORS.

Jon


Come off it...relax.

I may be wrong, but I think he meant that the non-painted SportCopter blades had to be polished and that was a bear to keep 'em lookin' good?!

You don't seem to peruse the threads too often, as the SportCopter blades are held in high regard. Get with it.



Cheers :)

[Master Roda]

I must be out of the loop!!! :wacko:

My bad......

Jon

[tyc]

... they had a hydraulic wing flexer set up that flexed a wing up and down using hydraulic rams running 24/7. ... The test they were running at the time was an 80,000 hour test and if the wing passed that test they could give the wings a 20,000 hour lifespan in the actual airplanes. ... they only can rate the wings at 25% of what they actually pass in testing.


A couple of points here ...

When I posed the initial question, I made mention that the manufacturer of the defective blades was not mentioned. This was incorrect. The firm making those defective blades was identified and did make good on both the original and as I understand it, the replacement blades as well.

In another posting in this thread an individual noted that there were essentially two (2) inspection processes which determined that the main rotors of a given gyro were safe to use. One method was by personal inspection, one which should be employed as a matter of course prior to every flight, and the other "by the hours" of actual use which have elapsed, both methods of which I was trained in.

The old Bell 47 wooden blades had no hourly use limits but were to be replaced on inspection. The Bell 47 metal blades were rated as good for 5,000 hours. The Hiller blades were good for some 6,600 hours, while the Brantly B2 series blades were rated at I believe, only 1,800 or 2,200 hours. If I''m not mistaken, in all cases, initially the metal blades for these machines had limited life hours which were a lot less. "Blood Lessons" or the lack of these gave rise to lower, higher and in some cases, remove and destroy notices.

In this thread someone noted that "homemade" blades were not limited by the number of hours they were used but service life was determined by the individual who made them and/or the individual who was using them. Mention was made that the initial Benson blades were considerably over built, some which to me comes across as what my old college professor would call "a happiness problem" and is somethig I for one am in full agreement with.

But that in this day and age, that there are individuals who are engaged in the commercial manufacture of blades, individuals who have not or will not offer written guarantees with regard to such flight critical items - that should be a concern to anyone entering that market.

tyc

[Doug Riley]

Ted, the mind-set that necessarily goes with flying home-built aircraft takes some getting used to. Any time limits specified by sellers are either guesses or are derived from one (or very few) incidents of failure.

Effectively, the "manufacturers" who sell "professionally built" components are simply home-builders like yourself. Pure eyeball engineering and rote copying are the rule.

There is no legal requirement that any of these folks have any knowledge of engineering or related fields. There is no legal requirement that the components be designed using any principles or procedures of science or math. The manufacturer has no obligation to test the components at all. In some cases, buyers have purchased a "production" item from a "manufacturer" only to find that the item was the (one and only) prototype!

This weird and wild landscape is very different from the carefully documented world of certified aircraft.

In the homebuilt world, you protect yourself by (1) knowing as much about the science of your aircraft as possible and (2) knowing as much about your seller as possible. Some sellers do an excellent job, but it's all on the honor system. Nobody's checking.

[GyroDoug]

But that in this day and age, that there are individuals who are engaged in the commercial manufacture of blades, individuals who have not or will not offer written guarantees with regard to such flight critical items - that should be a concern to anyone entering that market.
tyc

Ted,

Welcome to the Experimental world. While it may seem that it would be wonderful if every thing we participated in was entirely safe and someone else would take responsibility for our success, that is not the real world. Nor would it really be in our best interest to be that way.

In the Certified Aircraft world that may be closer to the way the Federal Government has tried to arrange things, but in the Experimental world we are the only ones that take any responsibility for our safety. Along with all that responsibility come some wonderful freedoms that we enjoy to try new things and to use new, unproven engines or avionics. There are lots of things we can do that are simply not available to those who choose to go the Certified Aircraft route. If you are uncomfortable with that reality then the Experimental World is probably not right for you.

The Gyro World is a very small group of people. The potential market for any commercial enterprise to go after is so small that most commercial enterprises don't want anything to do with us. The Commercial Enterprises that do operate in our world, do so because of a love of Gyros and a desire to see our current situation change. No one is making any significant amount of money although many dream of the day and work to change that situation. I applaud their efforts and do all I can to help (by promoting the sport).

Best of luck as you pursue your flying goals!

Gyro Doug

[PW_Plack]

Ted, in the relatively few years I've been watching this sport, the few rotorblade failures have always been preceded by some obvious abuse or neglect. In short, these blades apparently take far less stress than helicopter blades, and if cared-for and not abused, do not appear to be a concern.

The overkill built into certificated aircraft world comes at a price. If Part 23 aircraft were all we had, many on this forum would never be able to afford to experience flight.

Flying amateur-designed rotor blades requires a higher personal risk tolerance, but does not appear statistically to be a cavalier step if you're responsible about care and maintenance.

[Hognose]

Safety regulation does not necessarily produce greater safety. To see an example you need to look no further than Great Britain, which has much narrower restrictions on experimental aviation than, say, the USA or France, and yet (1) has roughly similar experience with mishaps, and (2) sometimes allows less safe (but previously approved) aircraft to fly while newer and safer aircraft are excluded.

The Section S (FW) and Section T (gyro) rules look like they're wonderful models of consumer protection, but what they do is hold consumers back in a ghetto of dated and sometimes less safe equipment. The perfect example was when Barry Jones was going to fly a Magni around the world for charity. (Barry made it to India before having to break off). He had to get rid of his Magni and get an older model because, well, the older one had some kind of blessing from some kind of British bureaucrat, and the new model (which was remarkably similar, but had -- oh the humanity! -- a different model number) was not.

Another example from the USA is the 2005/06 attempt to mandate use of child car safety seats for small children on airliners. It was an attempt to solve a nonexistent problem which would have led to the at-risk "lap infants" being carried in automobiles instead. It was possible to calculate (and several folks did) the number of kids likely to be killed by that safety rule over the years, and faced with that, the bureaucrats backed off.

Yes, experimental aviation is largely unregulated. That's a feature, not a bug.

cheers

-=K=-

[tyc]

... it would be wonderful if every thing we participated in was entirely safe and someone else would take responsibility for our success ... No one is making any significant amount of money although many dream of the day and work to change that situation.


As years of experience have shown me, nothing is "entirely safe"; hiking; automotive or aerial travel - for starters and the idea of someone else taking "responsibility" was not and is not the purpose behind the initial question. Then as now what I'm looking for is, and for want of a better term, a benchmark, one on which I might be able to place a reasonable degree of faith in performance; i.e., if I'm advised by a competent vendor that the given item will last "X" number of cycles or hours, then it would be reasonable to expect that it will last that long and plan my affairs accordingly. As I'm writing this I'm reminded of the time about a decade ago when I looked into acquiring what was known as a "Baby Bell" helicopter. My inquiries regarding a list of the limited ife items as associated with that particular machine, remain unanswered to this date and than as now, such silence spoke and speaks volumes.

As it stands right now, should I go the gyro route, my own, hand built wooden blades appear to be the best route. Wooden blades on helicopters have been around since day one and for want of a better tem, this method of blade construction, with all its limits, is a proven technology. Reasonable flight times can be had with these but should one fail, I have no problem with accepting that it is I and I alone who am responsible.

In closing, the old story about wooden blades and a Sikorsky pilot has come to mind. As I understand it, back in the late forties (over sixty years ago) someone at Sikorsky thought it would be a good idea to mount a motion picture camera on the main mast and have it look down the length of one of the rotor blades while it was performing. It seems this was done and the subject pilot took the machine up, did some hover work and as well did a few turns around the plant and after putting the machine down, the camera and film were removed. After the film was developed, those involved in that particular project, including the pilot were invited to join in the showing and it prove to be a real eye-opener! Prior to that filming, no one but no one had any idea as to just what was going on down the length of those blades, and as I understand it, that man, that pilor never again went up in a helicopter.

tyc

[GyroDoug]

Ted,

I understand your desire to have a manufacturer tell you how long you can expect his rotor blades to perform safely. However, you are asking for something that simply is not available in the world we live in with Experimental Gyroplanes. While you may take this lack of information as a condemnation of the manufacturers and decide they simply can't be trusted and decide to build your own rotors from wood, you may be cheating yourself out of the benefits of more modern rotor technology available today.

I am not an aeronautical engineer and can not intelligently discuss the pros and cons of wooden rotors vs. aluminum or fiberglass rotors with you. However, there are hundreds of people that have been flying a variety of experimental gyros for the last 50 years. There are many in that group that are engineers and know much more than I will ever know on the subject. When that group of educated and experienced flyer's have evolved from home made wooden rotors to the current state of mainly aluminum rotors, I am willing to accept that as evidence that wooden rotors may not be the best option for me today. But you are free to go whichever direction you want with your life. That is the great thing about experimental aviation, you get to choose for yourself what you think is best and you get to live with the consequences of those decisions. I wish you the best as you travel your path towards your dreams of flight, where ever that may take you.

Gyro Doug

[Doug Riley]

Ted, folks here have posted links to some camera-on-rotor-hub movies. In fact, one of our own even made such videos himself and posted them just a few weeks ago. If you don't barf after watching them, you are highly resistant to motion sickness.

I don't know of any contemporary blade makers who quote a life. There's simply no advantage to doing so; it's a game they can only lose. Amateur results in such a variety of conditions that such a quote would be meaningless. Blades are sold separately from any particular model of gyro. The gross weight, speed range, control system design, mast stiffness and rotor head mass all have an effect on blade fatigue behavior. All of these criteria vary tremendously from one project to the next.

Bensen claimed his blades had unlimited life. Of course, nothing made of aluminum has an unlimited fatigue life since the stuff has no fixed endurance limit.

I've been hanging around this sport since 1969. I don't know of a failure of any blades on single-place machines that was not attributable to really rough use. Jim Vanek, Mr. Gyro Loop, reported seeing cracking in the graphite-fiber hub section of his Skywheels blades after many hours of doing aerobatics with momentary 4-plus G loads. Such loadings are very rare in more normal gyro flight.

The accident in Puerto Rico resulting from faulty assembly of blades sold in semi-finished condition has been mentioned here already.

There's been a scattering of incidents with blades on heavy 2-place machines. An early version of the RAF blades were time-limited to something like 400 hours after hub cracks showed up. A change in machining to eliminate a sharp "step" seems to have fixed that problem.

One or more Australian aircraft had cracking and one apparent in-flight failure. Perhaps the Aussies can fil you in about those.

Given their inability to control the use of the product in the experimental universe, I don't believe you can draw any conclusions from manufacturers'
silence about blade life.

[tyc]

Ted, folks here have posted links to some camera-on-rotor-hub movies. In fact, one of our own even made such videos himself and posted them just a few weeks ago. If you don't barf after watching them, you are highly resistant to motion sickness.
... Blades are sold separately from any particular model of gyro.
... The gross weight, speed range, control system design, mast stiffness and rotor head mass all have an effect on blade fatigue behavior. All ... vary tremendously from one project to the next.
... I don't know of a failure of any blades on single-place machines that was not attributable to really rough use. ... momentary 4-plus G loads. ... very rare in more normal gyro flight.
... An early version of the RAF blades were time-limited to something like 400 hours after hub cracks showed up. A change in machining to eliminate a sharp "step" seems to have fixed that problem.
... I don't believe you can draw any conclusions from manufacturers' silence about blade life.


I'd be curious to see those links you made mention of and I have to ask, is non-destructive testing of the blade roots and the like common in the "experimental universe?"

tyc

[MikeBoyette]

Tyc,
My father did very extensive testing of his blades before he sold them to the first customer. These tests included but, not limited to running them up to 600 + RPMs. He did this with a Chevy v-6 on fixture he made. He also did various peel tests on the skins to make sure the skins were going to stay glued. With all of these tests they were nothing like the testing his customer's put them through. In the beginning when a customer brought back a set of blades they wrecked dad would give them 10% ofo of their replacement blades. This gave him a good look at how they survived a crash. I have seen his blades bent almost 70+ degrees and the glue never let go. The aluminum would rip before the glue would even budge. All this being said. Nothing means as much as time and experience. My dad is approaching his 2000th set of blades. This is has been accomplished in 17 years. If you ask people in the gyro realm about the reputation of Dragon Wing Rotors I doubt you would find many that would have anything negative to say about them. In the gyro world there are not many who make rotors and probably none who meet your criteria. My advice to you is,ask around and check manufactures' reputation, and go from there. Good luck.

[Doug Riley]

McCutchen (of the Skywheels brand) also did some testing on a powered static rig. The process was detailed in the PRA magazine some years ago.

Some blade brands went through periods of poor quality, though. Rotordyne bonded blades were developed by the Bud and Steve Phaneuf of California. They sold the business to someone who did not read the instructions. The blades produced by that successor were prone to bond failures. The failures weren't catastrophic -- the skins would bubble up away from the spar or start to separate at the trailing edge, but, because the skin was single piece wrapped all the way around, nothing flew apart. Us good ol' boys riveted them and kept flying.

Subsequent owners of the Rotordyne brand have been more conscientious about the bonding process and (so far as I know) there have been no more problems with them.

I was a dealer for Rotordyne at one point. Before signing up, I asked for, and received, some bond samples. I ripped them apart and found that the glue joints "pulled metal." As Mike Boyette says, that's what you want to see. ( I crumpled up a set of Dragon Wings, too, and corroborate Mike's report that the glue joints don't separate even if the blades end up looking like an accordian bellows.)

[Doug Riley]

P.S.: For the camera-on-blade videos, go to the "Flying Videos" Section of this site and check the threads labelled "barnstorm2."

[tyc]

P.S.: For the camera-on-blade videos, go to the "Flying Videos" Section of this site and check the threads labelled "barnstorm2."


Found those links the other day.

On this end I have a dial-up connection so d/l the longer work is out of the question but the three minute version was interesting ... well done.

tyc