RAF 2000 crash

[enewbold]

For an expense of ~$100.00 in materials you can achieve, or come close to achieving, static longitudinal stability by fabricating and installing the Bruty/Boyer mod.

The aircraft will still have the low cabin but will be much more forgiving. I encourage you and other RAF owners to investigate this mod.

I still hope that RAF will consider incorporating this mod in their kit.

Where can I find out the detailed information of the modification you are referencing? Thanks very much.

=Ed=

 

[animal]

An RAF-2000 can snap upside down in about 1 second, far too fast for the rotor to follow.

I have heard this before and THAT is a truly scary thought! in 1 second there is no way you could respond fast enough to prevent it. I just know when I am flying the RAF that I am training in. I make very small and slow movements and wait for the machine to respond. I use to think the RAF-2000 was the neatest machine made. after what I read of all these crashes and after flying it my self, I no longer want one.

Stability issues is one of the main reasons I started the thread about the Boykins gyro and if it will be worth makeing flyable. so far the Poll point to worth working on, but I have not gotten much response yet on if it looks like it will be stable.

At any rate I hate to hear about another Gyro crash. No matter what make.
Sad fact is no matter what the couse we have lost another pilot and a family has lost a loved one.

 

[quadrirotor]

A spinning rotor is a flywheel that resists having its plane of rotation changed. Perhaps you’ve played with a spinning bicycle wheel.

To change the plane of rotation of a rotor, lift forces must be generated that overcome its inertia.

To tilt a rotor nose down, the advancing blade must increase its lift while that of the retreating side decreases.

If the increased lift required is greater than the blade can supply, it stalls.

With a large offset of propeller thrust line and CG, the nose down fuselage acceleration can be very high; if there’s a momentary reduction of rotor thrust; it becomes self sustaining because as the rotor unloads, the nose pitches down, causing even greater unloading of the rotor.

In this particular accident, the pilot was shooting touch and goes, most likely climbing out at high power setting but relatively low airspeed where the horizontal stabilizer was ineffective. The pilot would have had a better chance had the stab been centered in the propeller slipstream.

An RAF-2000 can snap upside down in about 1 second, far too fast for the rotor to follow.

Does a smaller rotor follow quicker??? does an elevator in the prop-stream could prevent the snap upside down? does a neutral propulsion could help not to be bothered by the precession of the propeller also???

 

[Udi]

...He did state that the pilot had a tendency to do very steep climbs and then push over to level...

My condolences to the family.

I have seen CFI Jim Logan performing the above mentioned maneuver at Mentone and I was holding my breath every time. We don't know the exact cause of this accident, but It seems Mr. Monard was not aware of the risk involved of doing this kind of maneuver in a high thrustline gyro. I suspect having Jim Logan's example gave him the confidence it could be done safely.

Udi

 

[C. Beaty]

André, the speed of following of a rotor depends upon its ratio of mass force to aerodynamic force, designated by the Greek lower case letter Gamma.

It varies as R^4/I

Where R is the radius from the flapping hinge (teeter bolt) and I is the mass moment of inertia about the flapping hinge.

Smaller, lighter, faster rotors will precess faster.

But that’s not the issue here. What good would it do to have a rotor that could precess 180º in one second if your neck breaks in the process?

It’s not all that difficult to design a gyro that doesn’t behave like a rotary lawn sprinkler when rotor thrust is reduced.

 

[Chuck_Ellsworth]

WHY, WHY, WHY do we have to read about people being killed time after time in the gyro community in these unstable dangerous machines?

If these were high powered high performance cars sold as kits by some company with sloppy tie rods in the steering that could only be driven by highly trained highly skilled people and even then there was a steady stream of fatal accidents caused by sloppy steering, how many years could such a company stay in business?

What is wrong with the gyroplane community that seperates them from the rest of aviation that allows a few to keep defending something that can be cured by changing a design?

Or am I just making unfounded assumptions because I am biased?

What a dismal way for everyone here to start another day thinking about another family suffering the loss of a family member flying for fun.

Chuck E.

 

[Mayfield]

Amen Chuck. I apologize for ever taking issue with the way you present your view point. This is heartbreaking.

Many of us fly fixed wing aircraft as well as gyros. We would never dream of flying an airplane with the CG far aft of limits. Many of us, however, fly gyros with exactly the same longitudinal stability characteristics as a tail heavy airplane and then defend our positon by saying it "requires more training."

Ed,

Paul Bruty and Larry Boyer post here. Larry has indicated a willingness to share drawings and Paul will share his expertise.

Jim

 

[Rando]

Flying is dangerous!

Flying is dangerous!

When I first read about the crash of the RAF 2000 I almost missed it because it was grouped in with a bunch of other crashes of fixed wing aircraft. FLYING IS DANGEROUS! Check out the following accidents that occurred during the past few day.

Accidents: 6 Reported

2 Fatal – N606RV/Vans RV6, VFR, Thursday, November 02, 2006 at 7:00am crashed in the Bartlett Dam area and submerged. Aircraft departed the Phoenix-Deer Valley Airport VFR.

2 Fatal – N158MD/Zodiac, VFR, crashed in a field 20 miles south of Yuba City CA. Witnesses reported the aircraft exploded and broke up in flight.

2 Fatal – N15852/PA32, 11/05/06, IFR, from LIT to PWA when the pilot advised ATC that the engine was running rough then advised ATC that the engine was on fire and they were going down at 0520Z. The wreckage located 2 miles south of the Danville AR Airport (32A) at approximately 1300Z.

2 Fatal, 2 Injured – N53443/C172, VFR, departed TUL for ICT. A short time later someone on the aircraft called 911 and the Ponca City OK sheriff’s office received the call that the aircraft had crashed and search and rescue began. The wreckage was later located.

1 Fatal – N107TM, Experimental RAF 2000 GTX Gyroplane, crashed under unknown circumstances at Ridgely Airport, MD.

1 Fatal – N4141J/C180, VFR, crashed after the engine failed while landing at Cordova AK.

 

[Mayfield]

Randy,

I agree that flying, like many activities, is dangerous.

I have been fortunate enough to have flown all the fixed wing types you listed except the Zodiac. If they were loaded within limits they were stable aircraft. Whatever got those pilots and passengers, it was not static longitudinal instability.

As for the RAF accident I do not know what caused this accident. It could have been pilot error or incapacitation, or mechanical failure, or a PPO.

If you ever have an accident, God forbid, in your Dominator I know with great certainty; it will not be a PPO. It will also probably not be a PIO. You have chosen to fly a gyro that does not have a significant imbalance of forces. You have taken those possibilities off the table and thereby improved your odds. Sorry to pontificate Randy. I know you know all this stuff.

I guess my point is that flying is dangerous enough for us ground bound creatures. Why would we want to fly any aircraft with known deficiencies?

R/S

Jim Mayfield

 

[LARRYEBOYER]

My condolences to the family. I am saddened by any needless loss in the gyro community.
I just said the other day how nice it was to not hear of a RAF accident because it appeared most RAF pilots were adding stability measures (stabs, keel mods,stabilators, ect.) to make their aircraft safer.People were wanting to buy two place machines and values were esculating. Now reality rears it's ugly head.
It appears we want to attack the RAF design when we don't know the facts. Let's not forget that mechanical and/or pilot error can also be the cause. The Sparrow Hawk is pretty much a point and go aircraft as far as stability. Yet we have experienced crashes with and without fatalities.Does it have to reach a certain number of fatal crashes before we label the design flawed, or do we start with pilot error/ mechanical first? Then blame the design. In the case of the RAF, it appears we always blame the design.
Mr. Beaty. Are you saying that the rotors can stall if I attempt to fast of a climb? If so, then these high powered gyros with larger and larger engines could possibly stall their rotors with a high powered pullup?
If you have a high thrust line machine consider adding stability features and fly with in your skill level regardless of the machine you fly.
I am willing to discuss a quick fix for the RAF and I do have drawlings now.

 

[Doug Riley]

Once more, for the record:

The HS's currently being installed on stock RAF gyros are not even close to powerful enough to prevent PPO. At 60 mph, at least 14 sq. ft. are needed, but 20 would be more comfortable. At 40 mph, even 20 sq. ft. is not enough.

If the HS is not immersed in the propwash, then there is always a speed below which it will not prevent PPO, no matter how big it is. To get around this problem, you must either immerse the H-stab in the propwash, or get rid of the HTL arrangement.

The accident sequence is predictable: A low-G maneuver at full throttle reduces rotor thrust. Without rotor thrust holding the nose up, the craft starts to pitch over. As it does, the HS "sees" a higher and higher negative angle of attack. The HS makes more and more down-load. However, if the down-load isn't enough to stop the pitching by the time the AOA reaches about 12 degrees, it's all over. The HS stalls and the PPO proceeds to its fatal conclusion.

Those who have installed these H-stabs should not fool themselves that they have made their craft PPO-proof. Both the numbers and hard experience tell us that's not true.

Someone doing the Boyer mod should also do the numbers on it. Otherwise, it's apt to become the next "incomplete" fix.

We really should quit this "guess and gosh" stuff, folks. The grief and suffering are enormous, and we look like complete idiots to the rest of aviation. I have asked three or four advocates of RAF stabs to investigate and toss me some numbers. Not one has been willing or able to do it.

What is so damned hard about testing your H-stab, developing a lift curve and then designing from there? I've attached a photo (that I've posted umpteen times before), showing one simple rig for testing H-stabs.

 

[Heron]

Do we all agree that it was a PPO on top of a climb?
Are there enough evidences?
RAF = RIP?
sad
Heron

 

[barnstorm2]

Mr. Beaty. Are you saying that the rotors can stall if I attempt to fast of a climb? If so, then these high powered gyros with larger and larger engines could possibly stall their rotors with a high powered pullup?

Larry, I think that the case is a steep climb then some action (such as a quick level-off) that causes the RRPM to drop from rotor stall.

So long as the rotors are loaded I don't beleave there is a problem.

I will admit to being quick to blame the RAF design but if the pilot is educated and trained in PIO/PPO I also blame the pilot. This makes me a double talker cause I also blame the FW community for blaming gyros as problems and not gyro pilots.

I would not have jumped to the conclusion of RAF-design being part of the problem until I heard a witness discription of the accidnet which indicates the well known symptioms of a bunt-over.

I would like to say that all of my information is second had and I very well may be quite wrong.

Keep your rotors loaded!

 

[Joe Pires]

My prayers go out to the family and to those of you who knew and loved him.

 

[Chuck_Ellsworth]

" When I first read about the crash of the RAF 2000 I almost missed it because it was grouped in with a bunch of other crashes of fixed wing aircraft. FLYING IS DANGEROUS! Check out the following accidents that occurred during the past few day."

I'm not exactly sure of what you are driving at Randy, however may I point out that flying if trained properly and flying in properly designed aircraft and using good decision making process's is far safer than most other forms of transportation.

 

[Mayfield]

Someone doing the Boyer mod should also do the numbers on it. Otherwise, it's apt to become the next "incomplete" fix.

Doug,

As usual, I believe you are entirely correct. My preference would be something like the AAI mod. As I look at the Bruty/Boyer mod however I can not think of a way it could not make a significant improvement to the static longitudinal instability of the stock RAF. Is it enough? I simply do not know. I guess I just want it better than it is by whatever degree I can talk folks into.

Respectfully,

Jim Mayfield

 

[Doug Riley]

Jim, I understand your very humane point. Improve the odds.

There two issues with that, though. First, obviously an incomplete fix will still allow unnecessary fatalities. Like this one.

The second is more insidious. RAF's line of disinformation is that the HS doesn't do any good and, in fact, is "dangerous." Accidents like this appear to support that nonsensical position.

We really need a fix that PREVENTS PPO. Despite what several CFI's teach, PPO is not an inherent quality of gyroplanes. It's an inherent quality ONLY of gyros having a certain specific design error. Other aircraft with the same design error can, and do, also PPO. We just need to fix the mistake -- altogether.

 

[Mayfield]

Both good points Doug.

I know Larry and Paul have both done some measurements.

Although a pain in the butt, it might be a good idea for Larry to do a double hang test and find out for sure how much thrust line offset remains after his mod.

R/S

Jim Mayfield

 

[Student]

WHY, WHY, WHY do we have to read about people being killed time after time in the gyro community in these unstable dangerous machines?

If these were high powered high performance cars sold as kits by some company with sloppy tie rods in the steering that could only be driven by highly trained highly skilled people and even then there was a steady stream of fatal accidents caused by sloppy steering, how many years could such a company stay in business?

What is wrong with the gyroplane community that seperates them from the rest of aviation that allows a few to keep defending something that can be cured by changing a design?

Or am I just making unfounded assumptions because I am biased?

What a dismal way for everyone here to start another day thinking about another family suffering the loss of a family member flying for fun.

Chuck E.

There's one answer that comes to my head everytime I read that question, Chuck: Education.

I don't think the average gyro pilot understands the physics behind what they're flying. There are a few of you who have a great understanding and are nice enough to enlighten the rest of us, but the message is not getting to the masses.

I'd like to think that none of you gyro pilots have a death wish. If someone were to actually be convinced their aircraft could kill them, I can't see them flying it. And by convinced, I mean getting past the ignorant "it won't happen to me" mentality that seems to plague any accident, gyro related or not.

Something else that sets gyro flying apart from other forms of transportation is a governing body that ensures the safety of pilots. The FAA and NTSB don't have gyro accidents as a top priority. As experimental aircraft, maybe that's a loophole that allows them to disregard normal investigation proticol and move on to something else. As someone else pointed out, there's no shortage in aerospace accidents to look into. This forum is probably the only place in the world you're going to find knowledgable people on the topic of PIO, PPO, HTL and gyro stability in general. And for every member you have here, you have dozens of others who simply may not know the potential risks of flying a HTL machine.

Gyros may also be regarded as the "cheap" alternative to flight. With that mentality, the aircraft is not given the respect it deserves. I mean, it's just a goftcart with helicopter wings and a lawnmower engine, right? Unless they stumble across this website or a PRA chapter, they may never know the difference. And even within this community we can't all agree as to what is safe to fly and what isn't.

Scientific processes and experiments have to be completed and documented. That documentation has to be recognized as truth and someone with authority has to impliment these as laws. Without that, there is still a lining of myth and lore surrounding gyros. Without anyone telling RAF to do otherwise, they're able to market and bambazoole whomever they want. And what's worse, those salesmen may not even realize what they're doing and even if they have heard, they'd never believe it.

I don't know... it all seems simple to me. A bit of an outside prespective maybe. I don't fly, maybe that makes me unbiased. I live by numbers, calculations and physics. To me, I know a system that is not in equilibrium has to be moving. It's that simple. To others, the instance you mention moments, vectors and equilibrium, you might lose them completely.

 

[Gyropilot007]

Test Criteria

Test Criteria

Guys:

First of all, I had the pleasure to see this aircraft and meet its owner at Mentone this summer. It was a beautiful gyroplane and its owner was one hell of a nice guy. I am truly sorry for his family and the gyro flying community's loss.

On the subject of the RAF. I'm the first one to admit I'm no expert. Since purchasing my kit and beginning construction I've followed the various discussions regarding the pro and MOSTLY cons about the RAF-2000.

Well, the fact of the matter is that I own one of these 'death traps' and I happen to really love it. But this is not a blind love. I have taken much of the wisdom shared on this forum to heart. First, and perhaps most important, I have made the Boyer/Bruty modification to my machine. Secondly, I extended the keel 10 inches and installed a LARGE horizontal stabilizer with winglets. I'm very happy I've made these modifications but I'm not knowledgeable enough to know if, even after these changes, I truly have a stable and safe machine. If there exists a set of test criteria that I can perform to test the stability of my machine with these mods then let me know. I will happily do them and then post the HONEST results on this forum.

Best regards,

Bob McGuire