Warranties / Guarantees

[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