RAF owners/drivers (Part II) - standard RAF, stabilator, and friends

[davreich]

Hi,
This is a reboot and clarification for the original idea for the forum. After logging onto the Forum, using the Search function will find other information that is hard to find in the original RAF owners/drivers . Feel free to point out the search function and the modified RAF thread to others looking for information.

Please take the poll because others feel we are unaware of gyro stability issues; I believe we are informed. Thanks!

POLL CORRECTION: PPO is POWER Push Over not Pilot Push Over - I should check better. Anyone can take the poll.

[chuter]

PPO stands for Power Push Over, not Pilot Push Over.

Is this poll for RAF drivers only?

[Mayfield]

Hi dave,

I applaud your poll.

I believe you should ask a few more questions:

1. Do you believe that the stock RAF 2000 is statically unstable in pitch?

2. Do you believe that a longitudinally unstable aircraft is prone to PIO and PPO?

3. Do you believe that PPO is an unrecoverable, fatal event?

The reason for my suggestions is that if these questions are not answered in the affirmative it means that we (instructors and examiners) have failed as educators.

I hope you believe I am sincre in my suggestions and am not putting you down in any way.

R/S

Jim

[davreich]

Hi,
Those are great. Hey, that was my first try at a poll and I goofed part of it up. Let's see how that one goes then we could do a follow up poll adding those questions. (I found out length is limited in some areas.) I think you can only do a poll with a new thread, but that shouldn't be a problem either. Thanks!

[C. Beaty]

I wonder if this victim had heard of power pushovers, Dave?

http://www.ntsb.gov/ntsb/brief2.asp?ev_id=20050708X00957&ntsbno=CHI05LA163&akey=1

CHI05LA163

HISTORY OF FLIGHT

On July 4, 2005, at 1850 eastern daylight time, a Becker RAF 2000 amateur built gyrocopter, N481KB, collided with the terrain following a loss of control while in the traffic pattern at the Gladwin Airport (GDW), Gladwin, Michigan. The commercial rated pilot was fatally injured. The gyrocopter was substantially damaged. The 14 Code of Federal Regulations Part 91 solo instructional flight was operating in visual meteorological conditions without a flight plan. The local flight originated from GDW shortly before the accident.

A witness to the accident reported the pilot had made three takeoffs and landings prior to the accident. Following the third landing, the pilot had a radio conversation with his instructor during which the instructor asked the pilot if the gyrocopter was out of trim. The pilot stated that it was trimmed. According to the witness, the pilot took off again and was making the turn from crosswind to downwind when the accident occurred. He stated when he looked at the gyrocopter it was in a turn and when it looked back it was descending. The witness stated he did not notice any change in the sound of the gyrocopter prior to the accident.

Another witness reported that he was on the south side of the airport when the accident occurred. The witness stated he first saw the gyrocopter taxiing east on the runway at a high speed. He stated that a few minutes later, he saw the gyrocopter taking off to the west. He stated the gyrocopter became airborne and stayed over the runway at an altitude of approximately 10 feet for a while prior to climbing out. The witness stated that once airborne the gyrocopter made a wide traffic pattern which was about one mile away from the runway. He lost sight of the gyrocopter due to the trees and saw it again as it was preparing to land on runway 27. He stated the gyrocopter landed. About 15 minutes later, he saw it taking off again to the west. He stated this time the gyrocopter made a traffic pattern that was about half as wide as the first time. He stated the gyrocopter passed directly over him at an altitude of about 50 feet above ground level. Again he temporarily lost sight of the gyrocopter when it approached the east end of the runway. He stated that he next saw the gyrocopter as it was landing and that this time the pilot made a touch and go landing. The witness stated that this time the gyrocopter made a traffic pattern that was closer than the last one. He stated the gyrocopter was between his position and the runway, and that it flew over the pond at an altitude of about 150 feet. He stated the gyrocopter then entered a 25 to 30 degree nose down attitude which it maintained for 3 to 4 seconds prior to entering a 45 degree nose down attitude. The witness stated the gyrocopter lost about one-third of its altitude prior to the main rotor blades folding up and over the gyrocopter, possibly striking the propeller blades. He stated the nose of the gyrocopter then rose and it flipped over backwards. He stated the gyrocopter spun backward and sideways until it impacted the ground.

PERSONNEL INFORMATION

The pilot held a commercial pilot certificate with single-engine land and instrument airplane ratings. The pilot was receiving instruction toward obtaining a rotorcraft - gyrocopter rating. The accident reportedly occurred during the pilot's first solo flight in the gyrocopter.

The pilot's most recent medical certificate was issued on April 27, 2004. The medical certificate contained the limitation, "Holder shall wear lenses that correct for distant vision and posses glasses that correct for near vision and intermediate vision." According to Federal Aviation Administration (FAA) records, the pilot reported having 3,103 hours of flight experience as of the date of his most recent medical examination. The pilot's logbooks were not located during the investigation.

AIRCRAFT INFORMATION

The two-place, amateur-built gyrocopter was powered by a Subaru EJ22, 130 horsepower engine. The tricycle gear gyrocopter was equipped two main rotor blades and a three bladed propeller. FAA records indicate an Experimental Airworthiness Certificate was issued for N481KB on March 4, 2005. The pilot was also the builder of N481KB.

Logbooks or other records were not located for the gyrocopter. The National Transportation Safety Board Pilot/Operator Aircraft Accident Form 6120.1/2 was completed by the pilot's son. On this form he indicated that the gyrocopter had accumulated more then 40 hours of total time.

The pilot's flight instructor reported to an FAA inspector that he flew with the pilot in N481KB on the day prior to the accident and he adjusted the rotor pitch to accommodate the weight of two people in the gyrocopter.

METEOROLOGICAL INFORMATION

The closest weather reporting station was located at the Mount Pleasant Municipal Airport (MOP), Mount Pleasant, Michigan. MOP is located approximately 24 miles south-southwest of GDW. The MOP weather conditions listed at 1855 were: Wind - 260 degrees at 3 knots; Visibility - 10 statute miles; Sky Condition - 2,500 broken; Temperature - 24 degrees Celsius; Dew Point - 21 degrees Celsius; Altimeter Setting - 29.92 inches of Mercury.

WRECKAGE AND IMPACT INFORMATION

The FAA conducted an on-scene examination of the accident site. The gyrocopter came to rest inverted in an open field located on the south side of runway 27. The initial impact marks were next to the main wreckage. Visible on the ground was a curved slash mark which matched the length of a main rotor blade.

Both main rotor blades were intact. One main rotor blade was bent beginning at the root of the blade and the other was bent downward beginning about one-third the blade length from the root. One of the blades had impact marks on the bottom of it. This marks matched up with the location of the propeller. The outboard section of the propeller blades was damaged and/or missing.

Continuity was established to all of the flight controls. Fuel was found in the fuel filter and fuel lines. A large area of vegetation blight was visible at the main wreckage site. Engine continuity was established. The induction air filter was clean.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy was conducted on the pilot at the Hall Funeral Home in Gladwin, Michigan, on July 6, 2005.

Toxicological tests on the pilot were conducted by the FAA Toxicology Accident Research Laboratory, Oklahoma City, Oklahoma. Negative results were reported for all tests performed.

ADDITIONAL INFORMATION

The FAA was a party to the investigation.

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[RockyMeLad]

Dave,
It appears that you have assumed for the poll that only RAF owner/pilots should submit, but it isn't clear and would make a big difference in the result.

[Screw]

Screw-In

Is RAF (Duwayne Hunn) really comming to the "PRA Mentone" airport and start giving instructions in these machines?

Imagine. The headquarters for gyroplanes, offering instruction in RAF's. Do you think they'll have a Horizontal or a Stabalator?

SparrowHawk, I can see. RAF, I cannot.

Screw-Out

[Harry_S.]

Screw;

Have you ever had a ride in an RAF?

Have you ever had the controls, in flight, in an RAF...with or without an HS?


Cheers :)

[Harry_S.]

Hi dave,

I applaud your poll.

I believe you should ask a few more questions:

1. Do you believe that the stock RAF 2000 is statically unstable in pitch?

2. Do you believe that a longitudinally unstable aircraft is prone to PIO and PPO?

3. Do you believe that PPO is an unrecoverable, fatal event?

The reason for my suggestions is that if these questions are not answered in the affirmative it means that we (instructors and examiners) have failed as educators.

I hope you believe I am sincre in my suggestions and am not putting you down in any way.

R/S

Jim


No disrespect offered here Jim...but,

I answer in the affimative to your threesome except for #2. I believe all aircraft are subject to PIO...stable or unstable...PIO is a result of the pilot's control input?!


.

[Aussie_Paul]

No disrespect offered here Jim...but,

I answer in the affimative to your threesome except for #2. I believe all aircraft are subject to PIO...stable or unstable...PIO is a result of the pilot's control input?!
.

PIO is a result of the pilot's control input?! and then the instability compounds the problem with a divergent reaction to the pilots input. You should not have to die due to a small error in control.

Aussie Paul.:)

[Harry_S.]

Paul...I had reference to ALL aircraft...not just a specific type.

Your anti RAF pulse is really starting to show?!:rolleyes:


Cheers :)

[Mayfield]

Thank you Harry. On number 2, maybe I could have been more articulate (precise).

Indeed, as you state, any aircraft (RAF, SparrowHawk, C150, etc.) can be oscillated in pitch by the pilot.

Two thoughts:

1. If an aircraft is statically unstable in pitch it is easier for the pilot to get out of phase with the aircraft. Forgive the pontification to follow. If the aircraft is unstable, it will have a tendency (static stability is defined as a tendency to return to the trim state) to pitch in the wrong direction following a disturbance. Because the period of the pitching motion just about matches our reaction time (well maybe us old folks are slower) we inevitably get behind when we try to correct the pitch excursion. Unfortunately this leads us to the next characteristic of a (by definition) unstable aircraft. You can not just let go and have the excursion damp out. Each diversion, after the initial excitation, gets bigger and bigger.

You, other RAF drivers, and even me when I was flying one, are very familiar with the "reverse jab method of control." For example: the aircraft pitches up and we (with experience) wait for it to start pitching down. We then catch it with a well timed back pressure on the stick and then in a few thousandths of a second we relax the back pressure, or even give it a little jab forward.

2. As you and I have both stated, any aircraft can PIO. Most fixed wing drivers that fly C206s or Bonanzas, are often tempted to load these aircraft aft of limits. When they do they discover that the controls just feel funny. Any little turbulence makes them start to oscillate the nose up and down.

I know you've heard this but its a good review. With any aicraft; when the lift (RTV for us) gets ahead of the CG, The aircraft will try to respond to a pitch excursion in the opposite direction from what it should. A pitch up begets more pitch up and a pitch down begets more pitch down.

Unless very very unstable, or close to the ground trying to takeoff or land, a small degree of pitch instability in an airplane is scary and irritating. With enough instability we can exceed the safe G load tolerance of the airframe and pull the wings off as we chase pitch up and down.

What bites us (hard) is that the variable incidence wing we call a rotor spins at a safe RPM, in part, because of the weight slung under it. Every time we reach the pitch down phase (less G load) of a PIO, we loose RRPM, lift, and rotor rigidity. One of the net results of this is that the engine thrust (on an arm) continues to try to rotate the aircraft nose down.

If that were not enough, control of the airframe requires "control power." If we have 100% control power at 1 G, at half the G(G load is always reduced when the aircraft pitches down) we have half the control power. At zero G we have (with our teetering rotors) zero control power. We can pull back the stick. The rotor will follow the command. The airframe can not follow the rotor with no control power.

That's why paint, from the prop and tail, on the bottom of the rotor is a dead give away that a PIO/PPO accident occurred.

Wow! You asked a simple question and I bent your ear.

Jim

[Screw]

Screw-In

Harry, Would you have built or bought one if you knew then, what I know now?

Screw-Out

[Harry_S.]

Jim M...Your post #12 was well thought out and well phrased...so that even I could understand it.:D

Jim, I agree completely with your post. Thank you.


Cheers :)

[Aussie_Paul]

Paul...I had reference to ALL aircraft...not just a specific type.

Your anti RAF pulse is really starting to show?!:rolleyes:


Cheers :)

........where did I mention Raf? I was talkind about all unstable aircraft. I maybe anti the Raf company, BUT I am not anti Raf gyros. I want all gyros to be as safe as can be made. The Raf is a fine aircraft and can be made to meet the Sport Aircraft pitch stability standards.

Sorry if I offended you Harry, not my intent.

Aussie Paul.:)

[Aussie_Paul]

Jim, great post #12.

I thought that I said basically the same when I said, "PIO is a result of the pilot's control input, and then the instability compounds the problem with a divergent reaction to the pilots input."

My kids (in their 20's now) tell me that I have a way with words BUT it is not a good way!!!!!:eek:

Aussie Paul. :)

[PW_Plack]

Any aircraft can be PIO'd, but...

I PIO'd an Aeronca Champ a few times during training, and had a few "frisky" landings right after I was soloed, while I adjusted my trim and technique for the missing 190-pound instructor. I'm here to tell about it, because the aircraft behaved responsibly.

No amount of dual training can eliminate the butterflies, elation, increased workload and just plain strangeness of that new environment when you first fly alone. Our machines must be forgiving enough to help us survive those first few solos.

[Harry_S.]

Screw-In

Harry, Would you have built or bought one if you knew then, what I know now?

Screw-Out


Certainly John. I had heard the negative comments regarding the RAF before I had my two separate demo flights.

Just for your edification, only because you may not know, at the time I took those demo rides, I was what I would consider an experienced gyronaut. Don't get me wrong...I'm not bragging but I had 100's of hours in towed gliders and the same in powered machines. I made the comment sometime ago...that I have never...per the guru's...flown a stable machine, all were Bensen style and considered to be unstable.

Anyhow, I saw and felt nothing out of the ordinary when I flew those demo flights. As Jim Mayfield alluded...I subconsciously, from experience, added subtle control inputs to offset any instability...real or anticipated.

I flew my *stock RAF* for 90 hrs. before, and when, I decided to add the KJ stab. I added the stab on the basis of KJ's claim of increased performance and decreased workload.

I personally had no problem whatsoever in flying or controlling the stock RAF. This is not to say that the stock RAF, sans a stab, would be suited for a newby. I have been swayed, convinced, that a stock RAF is not for the inexperienced trainee.

And John...have you ever flown in an RAF??


Cheers

:)

[Aussie_Paul]

Any aircraft can be PIO'd, but...

I PIO'd an Aeronca Champ a few times during training, and had a few "frisky" landings right after I was soloed, while I adjusted my trim and technique for the missing 190-pound instructor. I'm here to tell about it, because the aircraft behaved responsibly.

No amount of dual training can eliminate the butterflies, elation, increased workload and just plain strangeness of that new environment when you first fly alone. Our machines must be forgiving enough to help us survive those first few solos.

That is one of the greatest statements ever.

I look at a gyro and say to myself, "Will that gyro help or hinder the inexperienced student?"

In my mind that says it all.

Aussie Paul.:)

[Harry_S.]

I wonder if this victim had heard of power pushovers, Dave?

http://www.ntsb.gov/ntsb/brief2.asp?ev_id=20050708X00957&ntsbno=CHI05LA163&akey=1

CHI05LA163

He stated the gyrocopter was between his position and the runway, and that it flew over the pond at an altitude of about 150 feet. He stated the gyrocopter then entered a 25 to 30 degree nose down attitude which it maintained for 3 to 4 seconds prior to entering a 45 degree nose down attitude. The witness stated the gyrocopter lost about one-third of its altitude prior to the main rotor blades folding up and over the gyrocopter, possibly striking the propeller blades. He stated the nose of the gyrocopter then rose and it flipped over backwards. He stated the gyrocopter spun backward and sideways until it impacted the ground.


Does this sound like a PPO?

It has been hyped that a PPO occurs within one second of initiation?!

This report is quite extensive from the initial report I had on file. I still have to consider...pilot incapacitation. Maybe not?! But the time interval...per the witness' statement...don't coincide with the standard split second occurrence of a PPO?! Nor of a PIO?!

Comments?

.

[Screw]

Screw-In

No.

Screw-Out

[Udi]

the gyrocopter lost about one-third of its altitude prior to the main rotor blades folding up and over the gyrocopter, possibly striking the propeller blades.
There were propeller marks on the rotor blade. One thing is obvious - the rotor slowed down, started flapping around, and the machine fell down. You tell me, Harry, what could cause the rotor to slow down to this extent? The only way this could have happened is after the rotor was seriously unloaded. Why didn't the gyro flip forward? Because the pilot cut the power when he realized he was PIOing. Unfortunately, not fast enough...

Notice there is no witness report from the instructor who was supposedly following the solo pilot from the ground with a radio (…Following the third landing, the pilot had a radio conversation with his instructor during which the instructor asked the pilot if the gyrocopter was out of trim. The pilot stated that it was trimmed….). How can these people live with themselves when their students die time after time?

Udi

[birdy]

I was go'n to stay outa this one, but i recon Harry's got a point.

[not tryn to sound crass but;]
Sounded to me like he was either dead before he hit the ground [no attempt to maintain control] or lost linkage to the rotors.
Since when dose a pio, or a ppo for that matter, take a smooth, steady ,uninterupted dive to the ground, with no power or pitch changes??

[Harry_S.]

There were propeller marks on the rotor blade. One thing is obvious - the rotor slowed down, started flapping around, and the machine fell down. You tell me, Harry, what could cause the rotor to slow down to this extent? The only way this could have happened is after the rotor was seriously unloaded. Why didn't the gyro flip forward? Because the pilot cut the power when he realized he was PIOing. Unfortunately, not fast enough...

Notice there is no witness report from the instructor who was supposedly following the solo pilot from the ground with a radio (?Following the third landing, the pilot had a radio conversation with his instructor during which the instructor asked the pilot if the gyrocopter was out of trim. The pilot stated that it was trimmed?.). How can these people live with themselves when their students die time after time?

Udi

Udi, I don't profess to be as knowledegable as you. I go mainly by gut feeling and from many hours of experience.

Reduced airspeed will definitely unload a rotor...I think. Reduced AS will cause the craft to descend at an angle...not vertically...and as the AS further decreases...a steeper angle until most lift is lost and then the rotor blades flap and contact the prop and/or the rudder. Years back, I experienced a lost of lift in an emergency situation and I'm considering it in this happening.

One important item...to me...is, why did the machine *flip backwards* before it hit the ground? I really don't understand that, unless the witness was mistaken.

I thought the same thing, Udi. Why did they not get a statement from the instructor? Did he disappear? If he were my student, I'd have been on the spot.

Udi...do you really think that the only people to die will be those flying the RAF? C'mon now. I follow the 10 day accident reports on the FAA web and I feel depressed at the number of fatalities in certificated aircraft.:(

I don't want to hear of another fatality involving a gyro machine, regardless of model...period.

This will piss some of you off real good, but I will say it anyway. I keep a record of all RAF accidents and from the info I get from the FAA reports...of the 38 RAF accidents since Nov. 1993...92 percent were pilot error, as can be ascertained. Of the 11 fatals...10 were pilot error. Bad statistics, but they're there.

Now...don't get me wrong...I'm not saying the stock RAF is a good machine for the inexperienced...it is NOT...but with an effective HS it is an effective training machine. That is my honest opinion.

[Harry_S.]

Addendum to the above post:

Except in a vertical descent.


.

[KenSandyEggo]

"Reduced airspeed will definitely unload a rotor...I think. Reduced AS will cause the craft to descend at an angle...not vertically...and as the AS further decreases...a steeper angle until most lift is lost and then the rotor blades flap and contact the prop and/or the rudder."

Harry, cut the engine on a gyro and it'll go wherever you want except up. In your scenario, you will merely flutter to the ground in autorotation. Haven't you ever cut to idle and just held the stick back as far as it will go? No way you can cause the blades to slow and fold. In fact, your rotor rpm will probably increase. If you push forward you will merely glide forward as in a normal landing. The further you push, the faster you'll go. I don't see any possible way one could slow the rotor and cause a tail or prop strike.

[mceagle]

I agree with Ken on this. Rotor speed has nothing to do with forward airspeed - it is directly related to load. You can go as slow as you like, the rotor speed will hardly vary.
The accident described does not make sense. It sounds like either confused witness reports (very common) or pilot incapacitation or disorientation, (or both).

[PW_Plack]

If I was training students in an aircraft with the stock RAF's stability profile, I wouldn't comment as a witness until I'd spoken with counsel.

[C. Beaty]

The only way an RAF-2000 can run into its own rotor is by precession stall, Udi.

With a machine configured like an RAF, it is impossible to so unload the rotor that it will flap before the machine can bunt (pushover). Slowing down the rotor requires a considerable time flying a ballistic trajectory, impossible without bunting first; at least with the engine producing thrust.

During the bunt process, rotation of the rotor plane is so rapid that it is unable to generate sufficient aerodynamic force to supply the precession torque and the rotor stalls, normally causing a loud noise similar to a canoe paddle slapping water. Witnesses often report an explosion.

The torque to precess the rotor is:

Torque = ωΩI

ω = angular velocity of rotor

Ω = angular velocity of precession

I = rotor moment of inertia

Units are: feet, slugs, seconds and radians

To precess an RAF rotor at 10º/second, required torque is ~1300 ft-lb; well within the lift capability of the rotor. You can assume the rotor aerodynamic center is at 70% radius and avoid integrating something that results in a partial differential equation.

Of course the precession stall is like putting on the brakes and the rotor slows at a very high rate following the stall. I doubt if it would be accurate, however, to say the rotor flapped into the propeller as during this process, there is no load being applied to the rotor. The airframe simply runs into its own rotor because the rotor can’t get out of the way.

Eyewitness reports about altitude, angles, pitch rate etc. have to be taken with a grain of salt. Watching someone tumble to his death is such a horrifying event that everything seems to happen in slow motion.

I’ve watched an early low rider AirComand, similar configuration to an RAF, tumble out of the sky and it certainly looked like everything happened in slow motion but it didn’t.

[mcbirdman]

Harry, Ah yes.... the pilot error thing...... when do suppose the pilot made his first real mistake? That is a classic way to minimize something bad that has happened to others so that you can somehow make yourself feel better because you are going to be different. Most accidents do happen as a culmination of pilot decisions.....

I think using that same pilot error scenario could be used to make the case that it may have started with misplaced trust and misinformation as the check was being written out. I could be wrong but it may have happened even sooner such as a demo ride where the case is presented that even though it doesn't have good lines and looks funky it fly's fine see????.......
Kinda hard not to get excited about something that is flying, even if it is on the edge. I know it is getting harder and harder to defend the lack of action and implementation of REAL solutions due to a poor configuration. Somehow I think that the canadian meaning of words such as safe and easy are misused by them as much as the phrases true-X country machine and pilot error.

Saying that you see no problem or assuming that your skill can overcome severe design flaws does not make a safe machine. It must be really be frustrating to have to decide to go against the manufacture recomendations to do something so basic. Even then it is no answer to PPO's without a major design change in the existing kits as well as any new kit rolling off the docks today.

It is also interesting to note that in this particular instance that the pilot just completed a 40 hour fly off which meant he could have easily had a passenger with him too?

Statistics ? How about 4 out of the 5 people I know in Michigan flying RAFs have had crashes? The one that hasn't isn't flying due to medical but was taught by one of the Ask First guys so he refused to use a stab. Probably not good to point out statistics because that is only one step away from physics and then there really wouldn't be anything left to defend.

Raf'ers guys keep creeping up to the edge of discussion to dispel the controversy with how it feels or asking have you done it criteria but the physics are unchanging. Doesn't matter how safe you feel or the fact that I haven't bunted. The machine has many inherent shortcomings that make it all opposite things that are advertised. How is that right or good for any of us? I know - it is a free world and the world is choosing..... Things are changing but I just can't understand why anyone would actively seek something out that is plagued with so many problems and the perception that the company isn't playing straight. Sincerely I am glad for your continued succsess Harry but I am even more happy for Sparrowhawk for their equally earned sucsess based on truth and started out of one too many losses of an RAF machine.

To sum it all up RAF grads can argue statistics or emotion but the company won't even talk design. Then they breed RAF pilots with flawed beliefs and feelings that can tell you they think it is ok but can't tell you why it isn't.

[gyroplanes]

While we are playing with statistics, James, Maybe it's not the RAF's "Severe design flaws" that are causing accidents in your area, maybe it's the State of Michigan!

I know of 4-5 RAFs each, flying in Indiana, Illinois and Wisconsin and none of them have crashed.

I don't mean to minimize ANY accident, especially a fatal accident. One of your Michigan RAF fatals was a friend of mine. I take every loss seriously.

But you have to face the facts.


There probably isn't a make and model of gyroplane that hasn't sent someone to an early grave.

Some gyroplane designs are easier to fly than others.

Some people believe that the gyroplanes they fly are stable and safe enough for them.

Ranting, raving and name calling will fall on deaf ears. You're wasting your time.

Most new gyroplanes being built and sold are easier and safer to fly.

The future is bright for the light gyroplane

[Chuck_Ellsworth]

Quote:

" But you have to face the facts.

There probably isn't a make and model of gyroplane that hasn't sent someone to an early grave. "

But we should be able to identify which ones are more prone to sending you to an early grave.

Just making a blurred general statement does not serve this purpose.

Can anyone here think of a make or model of gyroplane that has a reputation for killing it's occupants?

Chuck E.

[mcbirdman]

Tom, that was my point. Statistically someone could point out that I know a lot of Bad RAF'r pilots too! Or now statistically only 50% have crashed etc... With either contention it does not address the fact that these pilots choice of design and configuration may have stacked the deck against themselves in terms of pilot and passenger safety.

It seems priority should be to choose a design that isn't out of the box isn't an a flawed antique with it's only advantage being that they sell a lot of them or because there are a lot for sale cheap.

I know that anyone can easily screw up and I am never happy to read of another accident - it is very upsetting and I care too much. We have to accept our shortcomings as accidents do happen - especially when we are learning. Certain designs really do affect probable outcome however and I can't help but often think that in reality it is pilot error - but not as you think. I think accidents are usually a bunch of missed opportunities strung together in a timeline with unfortunate results.

It is up to us to limit the accumilation of vulnerability or pilot load before it gets strung together as an accident. Usually one would expect problems such as fixing a hose or tuning etc - not inherent flight design problems fixable only by redesign! (A bandaid is not a fix) Look how many years this has been discussed and the same old people are tweaking the same old machines the best they can while not actually eliminating the problem that wouldn't even be present in a properly designed machine. And all of this could be solved at the company level with a change of design and with a real commitment towards their customers safety as we have seen with the new alternative company that caters to people that like pushers. I agree Tom that their future is bright and it is good for all of us. But I also think that making strong points that cannot be countered or seem harsh because of the lack of an answer should be dismissed as shouting or name calling. It may be that the point is shouting out and if it is not true could be countered with some reasonable answer.

If safety is the priority and we are talking about safety concerns there sure is a lot to be talked about in terms of design, history, performance and focus shifting devices that do not eliminate the issues at hand. Most of the time RAF'rs hedge .......(see previous post)

As pilot in command you have to decide if the machine is safe to fly but if you are to listen to the company and follow their advice you may have your stringer mostly full by the time you start flying.

- I think the first most important step begins with what foundation you will be building your life on. At the very least the choice of design will affect how much you can depend on the aircraft to help you are vulnerable - and not take your life for a simple mistake that other aircraft would easily forgive.

Using the term pilot error to account for many accidents is too vague except for those who don't really want to take the time know the truth or realize that they bought into something much more complicated than they thought. After all the brochure says "finally a safe, affordable cross country machine".... Well, I realize people have to decide what they can afford and also realize what they may be paying with.

Tom I agree with all you said AND the facts as listed. It is obvious that while great strides have been made (see previous post) In the meantime many peoples dreams have ended in nightmares that were avoidable - it is dishearting to only see their experience reduced, explained or dismissed simply as pilot error.

[PW_Plack]

Tom said,

Ranting, raving and name calling will fall on deaf ears. You're wasting your time.

Actually, Tom, it's worse than wasting time. It's actually moving backwards. If we drive away 99 per cent of RAF fliers from the debate with rude tactics, we contribute to keeping them in the dark.

[mcbirdman]

Paul,

Nice of you to point out to Tom that he is wasting time speaking to me. Tom and I have spoke a few times and he knows what I mean without you trying to point it out through him.

Paul - Rant and Rave..... hmmm when they rave about how something feels and then have no answers concerning major shortcomings - my main point - people are sometimes quick to call it ranting because they don't want to hear it. There are two sides to an issue - even if one is undefendable.

Also If you noticed Paul a huge majority of people already here know about the failings and shortcomings of the design and do not approve how it has been handled. I also doubt that me or anyone else would be the reason they would continue buying into the farce or leaving it. As you can see they have made up their mind here no matter what. It is their choice but it isn't right to let other companies continue unchecked or unquestioned in their marketing practises and expect this problem to be just dropped so we can just get along.

If making a few points is Ranting - then what is their silence? Deafening? How is that ok then? No Answer is NO answer and everything stays the same.

[C. Beaty]

Paul, when people are genuinely interested in learning anything, the proper procedure is keep their eyes open and their mouths shut.

Haven’t you ever noticed that an occasional RAFer will bounce through here, call everyone a pack of idiots and never be heard from again?

A rational, open minded person wanting to learn the finer points of cricket playing, for instance, supposing there is a forum on the subject, will spend some time reading and not begin by calling the participants morons. I don’t think you would jump into the middle of a cricket forum without knowing the proper name for the little spark plug thingies they try to knock off of stakes.

Because of the criticism of the RAF design, owners have developed a bunker mentality, a kind of religious cultism and have closed their minds to outside influences. Proselytizing the faithful is an exercise in futility and it is totally irrelevant whether they are insulted or not.

The only hope is that people not yet commited can learn a bit about the mechanics of flight before they jump over the cliff.

[bpearson]

I think you will pick up the finer points of cricket a long time before I will have a clue what is happening in your American rugby football type game !

Maybe I'm on a sticky wicket as we say in GB.

Brian

[Harry_S.]

Quote:


Just making a blurred general statement does not serve this purpose.


Chuck E.

IMO, this is all you have done, as far as I have seen.

By gollies ...you'se guys.

Here you are; you dig up that dead horse's bones and are standing there, beating those poor bones.:(

I have a suggestion:

Ya'll pick out, one at a time, an RAF fatality report from the FAA records and we'll discuss (argue) the circumstances; rather than making a general statement that the RAF machine...not the pilot...is the cause of all the crashes.

.

Addendum.

Chuck B. As I was about to post this'n...I got notice of your posting. I have to go to the dictionary and look up your P word.:D

[Chuck_Ellsworth]

" Ya'll pick out, one at a time, an RAF fatality report from the FAA records and we'll discuss (argue) the circumstances; rather than making a general statement that the RAF machine...not the pilot...is the cause of all the crashes. "

Harry, I was one of the first people who post on these forums to state that the RAF 2000 is unstable and over the years I have been proven to be correct.

But maybe you think that someone in my business with my background needs to fly an RAF for more than a few hours to figure out that it is unstable?

[Dean_Dolph]

Gotta question! If bad pilots are the reason the RAF has a killer rep, does that mean only good pilots fly other makes? Strange if true since you would think there would be a proportional amount of bad pilots flying Doms, Magnis, Sparrowhawks and etc.; but those machines haven't acquired a killer rep.

[C. Beaty]

There is a school of thought, Harry, that holds there is no such thing as an accident.

When a circus acrobat falls off a high wire without a safety net and splatters, it is his own fault. He made the decision to get on the high wire without a safety net of his own volition. He may have misjudged his abilities or the wind but his fault non-the-less.

When a lion tamer gets eaten by a lion, it is his own fault. After all, he got into the cage with the lion as a matter of choice. He may have misjudged his abilities or the mood of the lion, but still his fault.

When Joe Sixpack gets in an RAF-2000, loses control and runs into his own rotor, it is his fault for having gotten into the machine in the first place. He may not have known he was dancing with the Grim Reaper but he would have if he’d spent some time investigating the situation.

Had he been in a Little Wing or a Dominator, he most likely would not be pushing up daisies but whose fault is that?

[mcbirdman]

They feel picked on because they have no answers and it sometimes feels like they have nowhere to go to spread their joy. It is hard for them to understand why going to an airport with their plane, a flyin or some social conversation doesn't spark the same enthusiasm they or the company has for it's product. But this comes for reasons worth seeking out.

Their reputation is what they make it and yes I go way back to Norms forum and let me tell you it is hard to believe they keep sticking their heads up to defend the machines and have to keep ducking them down to regroup because they have nothing but a feeling to shoot back. Ask them about the design, PPO, why that machine tends to PIO, what a stab is and if it is a worthwhile company frowned on addition.... what the fabelled magic mast or stabilator does...... and all we get is that we are rude and responsible for why the for the Rift in the RAF. They own and control their own reputation and destiny. Ultimately public perception matters most.

Rude or not is questionable. I may be short but I am not dumb. Our community should be more upset with the fact this has gone on so long and is still continuing. But if all we can get mad about and storm off about is not hearing what you want to hear..... Things will not change. People will still feel the same too..... but the facts still remain and will eventually be accepted like it or not.

[Udi]

...Here you are; you dig up that dead horse's bones and are standing there, beating those poor bones.:(
This is certainly true, Harry, but there is a good reason why we keep on beating this very dead horse. There are too many people out there, who have no clue the horse is dead! For them, the horse is still alive and kicking. The only way to keep this discussion in the front - for the benefit of the ignorant - is to keep on beating this poor old dead horse. I agree it stinks, but I believe in the Jewish saying that goes - He who saves one soul it's as if he saved the entire world...

If you believe people's lives are at stake, don't keep your mouth shut.

Udi

[Chuck_Ellsworth]

What is even more difficult to understand from my perspective is the venom that is directed towards those of us who are trying to save lives.


I have taken the liberty to paste this from another thread on this subject.

" Recent stabless RAF fatals have involved veteran pilots being transitioned. A guy should not have been signed off to solo if flying the pattern was "someplace his skills could not handle." I find it a stretch to blame the flying judgement of a 20,000-hour ATP, but that's just what RAF will do when he suffers a PPO. "

Of course it is a stretch, a stock RAF 2000 is a mouse trap ready to snap when you least expect it, why else would someone with thousands of hours lose control?

[Harry_S.]

I have a suggestion:

Ya'll pick out, one at a time, an RAF fatality report from the FAA records and we'll discuss (argue) the circumstances; rather than making a general statement that the RAF machine...not the pilot...is the cause of all the crashes.


Have I not stated that the stock RAF is not a stable aircraft...and without at least an HS, is not a suitable training AC for a newby?

Again...I offer my suggestion above.

.

[Harry_S.]

" Recent stabless RAF fatals have involved veteran pilots being transitioned. A guy should not have been signed off to solo if flying the pattern was "someplace his skills could not handle." I find it a stretch to blame the flying judgement of a 20,000-hour ATP, but that's just what RAF will do when he suffers a PPO. "



That's where we differ Chuck...a 20,000 hr. ATP with zero time in a gyroplane means...he's a newby to the gyroplane. It doesn't mean he can have an RAF demo ride and take off into the wild blue yonder.

I was highly experienced in gyro's for C*****'s sake and I didn't jump in and go. A bit of caution and common sense goes a long way in this regard.

.

[Chuck_Ellsworth]

Quote:

" Have I not stated that the stock RAF is not a stable aircraft...and without at least an HS, is not a suitable training AC for a newby? "

So based on your above opinion Harry, would you advise Martin Weaver to add an H.S. to that stock machine in his web site?

Or am I missunderstanding what you posted?

As to this by you:

That's where we differ Chuck...a 20,000 hr. ATP with zero time in a gyroplane means...he's a newby to the gyroplane.

So what about the high time Pilots who were trained and sent solo by RAF instructors, and lost control of their RAF's and died?

Chuck E.

[C. Beaty]

I’ve posted this before but I suppose there’s no harm in posting it again.

George Townson, in his book, “Autogiro, The story of the windmill Airplane,” speaking of Kellett KD-1s wrote:

“…The remaining five were given to the border patrol for Texas/Mexico border surveillance. They were declared surplus and drifted around Texas and Arizona. One found its way to Canada where Atlas Aviation wanted to use it for towing advertising banners. The Author “taught” their pilot to fly it by telephone, and he made a successful solo flight….”

The Kellett KD-1 was a 3-blade tilt head Autogiro with offset gimbel rotorhead, a tractor engine with care being taken to insure that the propeller thrustline passed through the CG. It had a horizontal stabilizer of 10’ span.

Can anyone imagine teaching a pilot, whatever his previous fixed wing flying experience to fly an RAF-2000 over the telephone?

[GyroRon]

I got aemail from Marty, he did his best to answer my questions I posted here for him.

He gave me a explaination about thrustlines that the rotor is one source of drag and the airframe is another, the prop is centered between the two....

[Timchick]

I never heard that one before. Learn something new every day.

[Udi]

...He gave me a explaination about thrustlines that the rotor is one source of drag and the airframe is another, the prop is centered between the two....
This explanation is technically correct, although it doesn't follow the same technical terms we usually use to describe forces that are acting about the gyro center of mass. The rotor thrust vector (RTV) may indeed be shown as the sum of two separate forces, or vectors - lift and drag (see pic below). The engine thrust really has to overcome all the sources of drag, including the rotor drag.

However, there is one flaw with the logic that Marty is presenting (which I've heard before). Rotor drag is not a force independent from lift. The rotor is really generating one force (RTV), which is perpendicular to the plane of the rotor.

In a gyro in which airframe drag and engine thrust are in line with the gyro center of mass, the RTV would also pass right thru the center of mass – the RTV would not create any pitching moments about the CG. In a gyro in which the engine thrust is higher than the gyro CG, the RTV is passing forward of the CG, countering the nose-down pitching moment of the engine. So technically, is it correct to say that it is the horizontal portion of the RTV (drag) that is balancing the engine HTL.

But even if we use Marty's point of view to analyze forces which, as I said, is technically correct, we can see the problem with the location of the engine thrust line. Say the engine is located in a place in between the rotor drag and the airframe drag, so all the forces balance each other. What happens when the rotor becomes unloaded and stops producing thrust? When there is no thrust, there is no drag - because rotor drag is not "really" drag, it is the component of the lift that is parallel to the direction of flight.

When the "drag" goes away, the "drag balance" goes away and the airframe will pitch nose down, with nothing to stop it -- PPO.

I hope that Marty and others who believe the engine should be located between the two drag forces will stick with us to hammer this out. We all obey the same laws of physics, and no one has a monopoly over it. Any technical disagreement can be worked out if the parties are willing to talk and listen to each other.

Udi

[C. Beaty]

For anyone interested, Cierva’s 1929 patent for CLT can be found here:

http://v3.espacenet.com/origdoc?DB=EPODOC&IDX=GB330513&F=0&QPN=GB330513

[Harry_S.]

Can anyone imagine teaching a pilot, whatever his previous fixed wing flying experience to fly an RAF-2000 over the telephone?


Nope!! Personally, I can't imagine that happening with any pusher, Chuck.


,

[C. Beaty]

With the engine rigidly bolted to the airframe, Harry, there’s no difference between a pusher and a puller, all other things being equal.

The engine’s thrust is applied along a line and the point along the line where the propeller is located is irrelevant.

The things we learned as children stick with us.

Pulling your Quacky Duck toy with a string provides good stability inasmuch as Quacky follows the string.

Push Quacky with a stick and he wants to swap ends.

When pulling him with a string, force is applied to a point ahead of the center of lateral resistance.

Pushing him with a stick applies force to a point located behind the center of lateral resistance.

But neither example mimics thrust applied along a line.

If you strapped a laser pen to Quacky along his centerline so you had a beam that pointed either fore or aft and always kept your stick or string centered in the laser beam, there would be no difference whether you pushed or pulled.

That’s the case of a propeller bolted to the airframe.

[Mayfield]

With the engine rigidly bolted to the airframe, Harry, there’s no difference between a pusher and a puller, all other things being equal.

The engine’s thrust is applied along a line and the point along the line where the propeller is located is irrelevant.

Push Quacky with a stick and he wants to swap ends.

.

Hi Chuck,

I may very well be missing the point, but it appears to me that if the stick was glued to the rear of Quacky like the engine is glued to the back of a pusher, we would not be able to tell the difference between pushing and pulling as long as the force applied was centered.

Jim

[Chuck_Ellsworth]

Harry S:

Further to Chuck B. using Quacky Duck as an analogy for the push pull force the same priniciple will apply for where the engine is bolted on Don LaFleur's " Rocking Horse "

You do recall Don describing the RAF 2000 as a "Rocking Horse " don't you Harry?

Chuck E.

[C. Beaty]

Sure, Jim.

If you glued a stick to Quacky that ran fore and aft along his centerline and strapped one of those toy rockets that used a CO2 cartridge to the stick, it would make no difference where along the stick the rocket motor was strapped as long as its jet exhaust was parallel to the stick.

We all are influenced by childhood experiences and it’s important that they be interpreted correctly.

[Udi]

I didn't have a Quacky Duck, but learned a lot playing with my little brother Formula One free wheeling racing car. That was before toy racecars came with a motor and remote control. You actually had to push your racing cars. Well, I decided pushing the car by hand was lame so I decided to equip it with a rocket engine. I took an aluminum broom handle and cut a 15" piece of it. I got one end shut and filled the "rocket" with gun powder (which I made myself). I then squished the other end to create a nozzle and stuck one of those ignition strings (don't know what these are called in English) to the end. Strapped the rocket to the top of the car with a bunch of duct tape and took it to the street for a test drive...

Me and my 3 y/o brother just stood by it as I ignited the string. Luckily none of us stood in front or behind the rocket. There was a huge boom and all we saw was the car, hardly moving, with a smoldering roof. The rocket was gone. A few seconds later we've heard the rocket smash into something on the other end of the street. That's when I ran to hide inside the house... My brother wasn't happy at all. I ruined his brand new racecar.

Udi

[Doug Riley]

Udi's analysis is on target. It's perfectly valid to divide rotor thrust into lift and drag components -- or any other components you want -- as long as you follow the simple rules of vector geometry. (Many of us got a taste of vector math in high school , and then got it all over again when we learned boat or airplane navigation.)

Thinking about the rotor drag component can lead you into faulty thinking if you're not careful. Those old vector math rules say that, when you split one force (rotor thrust) into two or more, you have to account for ALL of those components in order for your split-up to be valid.

There's a tendency to get fascinated with the drag component and forget the lift component.

If you make that mistake, you'll conclude that the engine thrust line MUST be above the CG in order to counter the rotor drag -- because the rotor drag is above the CG, too. One pulls one way and the other pushes the other way and it balances out, right?

In this mistaken "model," rotor drag is a good thing. It prevents PPO. A gyro with a magical drag-free rotor, so it says, would always PPO. Ralph Taggart even got swept up in this fallacy in his early edition of the Gyrobee materials. Many another gyro pilot has, too.

In this erroneous "model," all gyros automatically PPO during a neg-G event if the throttle is left open. In this "model," there's just no way to design out the PPO potential. All you can do is train, train, train people to avoid zero G-with-high throttle... because that combination is an instant sentence of death without appeal. It's a pretty depressing viewpoint, at least for a supposedly fun activity.

Fortunately, it's wrong. Those gyro pilots who've flown through zero G in a stable gyro and had nothing scary happen know this instinctively. But it also makes sense from the vector viewpoint.

Check back to Udi's diagram. Yes, drag pulls straight back, by definition. Lift pulls straight up, however. Therefore, the bugaboo of drag "pulling straight back at the teeter bolt" is simply wrong. It ignores the contribution of lift.

The two forces -- lift and drag -- together pull up-and-back at 10-12 degrees aft of vertical. There's no need to have the prop thrust line above the CG to "counter" rotor drag. In effect rotor lift does that for you. Put the prop thrust line right through the CG and simplify your world. Or leave the prop thust line a little above the CG and balance its force out with a HS.

The one thing you DON'T want to do is leave that prop thrustline high with nothing to counter it but rotor thrust. Rotor thrust really does quit in zero G, and the prop WILL push you over then if your pop thrustline is high. The good news is that zero G will NOT cause a pushover if the prop thrust line passes through the CG.

What a relief it is to know that. There's no reason to design a craft that denies you that basic safety.

[Chuck_Ellsworth]

I will be interested in reading any further offerings by Martin Weaver to debunk the information regarding the offset thrust line physics being discussed here.

[Harry_S.]

I didn't have a Quacky Duck, but learned a lot playing with my little brother Formula One free wheeling racing car. That was before toy racecars came with a motor and remote control. You actually had to push your racing cars. Well, I decided pushing the car by hand was lame so I decided to equip it with a rocket engine. I took an aluminum broom handle and cut a 15" piece of it. I got one end shut and filled the "rocket" with gun powder (which I made myself). I then squished the other end to create a nozzle and stuck one of those ignition strings (don't know what these are called in English) to the end. Strapped the rocket to the top of the car with a bunch of duct tape and took it to the street for a test drive...

Me and my 3 y/o brother just stood by it as I ignited the string. Luckily none of us stood in front or behind the rocket. There was a huge boom and all we saw was the car, hardly moving, with a smoldering roof. The rocket was gone. A few seconds later we've heard the rocket smash into something on the other end of the street. That's when I ran to hide inside the house... My brother wasn't happy at all. I ruined his brand new racecar.

Udi



I read this and betwixt me beer and laughing...I almost choked and lost my breath. That would be a good one to re-create on a video.:D

Really liked that one. Levity is sorely needed on occasion, here on the forum.:cool:


Cheers :)

[RAFRAT]

I gave a motorcycle ace a trip in the RAF to see if he would buy one to get around the circuits.
http://video.google.com/videoplay?docid=3303933690562306409&q=gyroplane
I also took a trip down to my sons field, which was a bit on the short side.
http://video.google.com/videoplay?docid=4712014750565777787&q=gyroplane
enjoy
jp