My Introduction to PIO and PPO (and survived)

The best yet

The best yet

Thanks so much stevek for sharing that with us. As a student pilot with much to learn, it is very serious that you start with a safe and stable machine. Life it to short to become a stat. There is just no real reason other than pure lazyness that you would need to fly a dangerous machine that needed attention every micro second of your flight.

Jonathan
 
Steve K,

You'll find the debate confusing, with seemingly qualified people arguing on both sides of the PPO question, until you understand their only real item of disagreement:

Can PPO happen spontaneously, a sudden, deadly rotation from straight-and-level flight caused by a gust or other turbulence, or is it only the final result of a series of oscillations which could have been caught by a pilot with proper training? Some will argue training is the best solution, others will say redesign the machine. My novice conclusion is, do both.

IMHO, this is the only argument left on the subject. I can find no one (outside the British government) who doesn't acknowledge that having the thrustline aligned closely with vertical center-of-mass doesn't create a safer machine. (Well, allright, outside the British government and one major Canadian kitmaker.)
 
Steve,

You asked what speed.

I suggest that when you learn to fly that you concentrate on controlling your speed with your cyclic stick and not your throttle and that you use your throttle to gain or loose altitude and not your cyclic stick. Throttle for altitude, Stick for speed.

Then, using your cyclic stick, maintain 50 mph for take off, climb, cruise, approach and landing. Keep it at the same speed during all phases of flight (until just before flare and touch down).

Then after you get used to flying the gyro (at least 10 hours) you can increase your speed.
 
I am getting the message!

I am getting the message!

rehler said:
Steve,

You asked what speed.

I suggest that when you learn to fly that you concentrate on controlling your speed with your cyclic stick and not your throttle and that you use your throttle to gain or loose altitude and not your cyclic stick. Throttle for altitude, Stick for speed.

Then, using your cyclic stick, maintain 50 mph for take off, climb, cruise, approach and landing. Keep it at the same speed during all phases of flight (until just before flare and touch down).

Then after you get used to flying the gyro (at least 10 hours) you can increase your speed.

Sounds like flying a FW. If my gyro is power stable then yes, increasing power should make the machine climb at the same speed and retrimming the rotor pitch, the gyro should stabilize at a new airspeed.

I am not sure yet whether my gyro has that stability in those two variable changes but it's the next thing I am going to find out - trying Gregg's 3 flight tests for the different static stability modes. If it doesnt, then I am in for a harder time I guess - until We can make the CAA see sense and allow tested mods to bring the characteristics back into a stable regime.

meanwhile, I will take your advice and stick to 50 knots at all time. Thanks for your advice. It's good to be able to have a sensible conversation with this group - I don't feel I can talk open mindedly in the UK. Too many toes to tread on and I do not want be be alienated by the small community I have to (and enjoy) mix with.

I am beginning to see that perhaps I am taking a cavelier attitude and must look like a prat who f**ked up and is looking to blame the tools.

I reackon that all Gyros should have a flight manual that shows the audited results of a set of flight tests along the lines that Gregg Gremmiger and his group are formulating. This includes the existing machines that pre-date section T. The flight manual should be made available when the machine changes ownership, so the new owner can make a better informed decision when purchasing it.

To work alongside this concept, the CAA/PFA , should assist in the design and authorization to preform whatever mods are required to help these old machines improve their staility ratings.

This would apply a positve incentive for the current owner to improve his machine -if not for his own benefit, but make it more ssaleable when it is sold on. The buyer will also also have a good idea what he is buying.

I could then see a dramatic imporvement in the whole gyroplane scene in the UK, with fewer accidents and pilots having fewer problems moving between types, as they should share more similar flying characteristics.

Have anyone come up with any benefits for an unstable Gyro?. I know they are plenty of examples in other forms of transport, often due to fast control response requirements on sports/racing/military aircraft. But i am not sure if they are relavent to the Gyro


Steve Kirkby
 
Steve,

The "stick for speed and throttle for altitude" is the same for all gyros, regardless of how power stable they are. That is how you should fly a gyro.

In general, you should never use throttle for speed or the stick for altitude.

It is the same as fixed wings only in "slow flight". Basically, gyros are always in slow flight.
 
Steve, I am glad your are considering all the possible problems as well as solutions. You said that many students you see just taxi back and forth in a (assuming two wheel) balance. A mistake at that point in training is only going to cost a set of rotor blades, and maybe a scar or two, not your life. As you found out once you are airborne, everything (wrong) can happen very quickly. In reality, it isnt happening all that fast, but your mind is not processing all that is happening, and reacting quickly enough. That comes with many hours solo piloting. The first few hours of solo flight in a gyro, I like most, had some poor landings. I look back at the mistakes now, just shaking my head why I did not make the correct inputs quicker.

I did my training in a dual very stable gyro. I also fly a very stable high performance gyro. That doesn't mean I have not been in one that was unstable, and it can be a unpleasant ride. I believe 1 hour of airborne dual is worth many hours of ground/internet/ best friends advice/etc kind of instruction. Balancing on the mains can be done with ground assistance. However once airborne a good instructor can help you recognize a flight problems before they get out of hand. I agree with Ken, that speed management should be a top priority, 50-55 MPH max till you get some hours built up. Don't take off if the wind exceeds what ever your instructor states. Our NTSB (goverment crash records) is full of high flight time FW pilots that have gotten into a gyro and fatally crashed within the first few hours (or sometimes seconds) because they think they are easy to fly. Well they are easy, it just takes practice and patience.

Scott Heger, Laguna Niguel, Ca SportCopter N86SH
 

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Gyros available to UK pilots

Gyros available to UK pilots

In my recent post I defended the Cricket gyro's safety record and flight characteristics. I did this partly because I believe it is a safe machine but also because of the following...... Here in the UK we do not have the freedom to fly what we like. The authorities will not allow us to fly proven machines let alone develop our own. They were bitten hard by the Air Command accidents. A UK enthusiast recently suggested all existing UK gyros should meet our section T requirements. The CAA would love that. No gyros would fly again....... problem solved ! If enough people say Crickets, Bensons are deathtraps they will be grounded. Then our gyro safety record would be the envy of the world.
Brian
 
Brian, if the goverment lowered the top speed limit in cars to 40 kph, your Country would have the safest accident rate in the world also. Sometimes regulations get silly. You have to remember, in the the U.S., the FAA is not really concerned for the pilot, but for protecting the public at large. If we had a bunch of accidents of gyros hitting persons on the ground or damaging others property, they would come down on us hard. The reality is I don't know of ANY accident in the past 20 years where a non passenger or pilot was injured by a FLYING gyro in the U.S. It may have happened, but it hardly any large public safety threat.

Many gyros are flown out of rural airports, and alot of gyro pilots don't have licenses to fly them. The culture in our Country is not to turn fellow pilots in for rule infractions. The FAA is way to busy to normally mess with some local gyro flyer unless he is making a hazard of himself. I fly into many Los Angeles area congested airports in both my gyro and helicopters. I have yet to be ramped checked as a pilot. Last year I actually parked next to a FAA field office, and four of the officals came out looked at the gyro, and never asked for any paperwork, even though two of the observers were inspectors. We do enjoy much more freedom here to design, modify(and improve) our machines without more than a log entry in the airframe book. Gyros in the U.S. are just a very small fringe aviation group. The more we can all do to present a good image of the sport, and disspell old myths, hopefully things will change for the better, and more people will get interested in the sport.

Scott Heger, Laguna Niguel, Ca SportCopter N86SH
 
Regulation in the UK

Regulation in the UK

Scott. I sometimes despair at the way our governing bodies view sport aviation in the UK. You are totally right. Example : We build our outdated gyro. We are not allowed to make it safer (someone fitted H/S to Cricket for export and test pilot said it was amazing........ two years on, still waiting to be cleared). We now need a trailer. No regulations here to speak off. Yet we tow our machine around, inches away from people knowing that if it were to fail we could wipe out a bus queue or derail a train... actually happened here three years ago.
We can build one off design cars, then after a reasonable inspection we can tear up the road alongside all the mass produced cars that cost millions to develop. I envy you and other countries that allow their people the right and freedom to decide for themselves what risks they can take.
I have argued for many years we need to recognise in law the disclaimer. But as lawyers run this country I doubt they would ever do themselves out of work !

Brian
 
Steve,
It is good that you are still around to tell us the story.
It sounds like a typical case of what is popularly called PIO to me.
PIO starts with the pilot over correcting a perceived attitude defect in the Gyro and if the pilots response harmonises with the pendulum frequency of the gyro, full blown PIO developes. If not stopped, the Gyro finally tumbles forward due to lack of corrective control movement, drag under or PPO.
A gyro student pilot should never be allowed to fly the pattern until he nas nailed the gyro "attitude" under all conditions likely to be encountered in normal flight.
 
Steve K., the problem is PRECISELY that your gyro IS inherently dangerous. It's not your fault. You're apparently caught in a strange political bind, but the laws of physics don't care about politics. Mother Nature certainly will NOT give you a break just because your machine's dangerous configuration is the result of politics.

To repeat, a pitch-stable gyro will not behave as you describe, even if the machine IS somewhat mishandled (as you also describe). A pitch-stable machine's nose gradually rises as you go faster, requiring more and more forward stick pressure to avoid climbing. A pitch-stable machine does not become twitchy or unduly sensitive as you speed up -- quite to the contrary, it feels "stiffer" and more solid as you add speed.

To be sure, there are specific techniques for handling unstable aircraft. So many gyro models were unstable in years past that these techniques came to be thought of as "standard gyro" techniques, which they are not. Among the supposedly "standard gyro" techniques that are really "standard unstable aircraft" techniques are (1) be ready to close the throttle at the first hint of PIO or turbulence (2) use short "jabs" rather than steady pressures when manipulating the stick (4) make liberal use of "reverse jabs" to stop rotations of the fuselage even before you're achieved the response you wanted (4) be very watchful for airspeed loss in turns, and be ready to use forward stick to prevent it (5) always adjust power before adjusting stick pressure ("power before attitude").

If you cannot legally add an effective horizontal stabilizer to your gyro and adjust the CG's vertical position for substantially centerline thrust, then all of these techniques will apply.

A stable gyro flies much like a fixed-wing plane, except for the effects of its lower lift-to-drag ratio. The special techniques applicable to unstable aircraft do not apply to stable ones.

Having flown unstable gyros for years and having switched to stable ones, I'm not sure I'd fly gyros at all if the government forced me to fly unstable configurations.
 
Steve, here in Brazil he don't have those constraints as you, english guys, but because of tradition, all our gyros are old fashioned, unstable configurations. That is unfortunate (hopefully we can change that soon); but my fellow pilots are flying for decades using those technics Doug just mentioned above. They don't even know things could be different.

Doug Riley said:
I'm not sure I'd fly gyros at all if the government forced me to fly unstable configurations.

I would. Excuse me, Doug, that is only my personal choice. It has to do with a dream to fly. Some things are stronger than logics. :eek:
 
Doug,

As i thought, I am being hit by both sides of the argument. Thanks for your suport and practical advice, It's surely appreciated. I wish I had found this forum earlier.

I shall be trying myself to go through the procedure to get a mod approved from the PFA/CAA. Perhaps if enough pilots in the UK were to do this, the message may get across that there is a requirement by UK pilots for improved safety for the lower hours pilots.

If I run across any genuine resistance for this from the authorites, I will post me progress on this forum.

and regarding the Cricket's safety record - It's no worse than any other non-stabilized Gyro and in all other respects, is a fine little flying machine. I have myself never gone to the extreme of saying they should be banned, but I do fear that if too vigerous a point is made to the authorities, that is exactly what could happen. So a little diplomacy is required (not generally my forte!).

My ideal scenario would be for the authorities to assist in allowing non factory mods to be made on the basis of safety grounds, and reducing the opportunity for pilot errors (as that seems to be the main reported cause of any accident that isn't attibuted to a structural failure)

With section T , I would hope that all new Gyro's will now fly in a stable and predictable fashion like fixed wing aircraft do and not have any unpredictable traits.

This still leaves the existing Gyro base. I would like to see formal test flight results relating to staic and dynamic stability being made available to the purchaser, if a Gyro changes hands. Together, with a simpler procedure fo mods to be made and perhaps the publication of approved mods as they become available, would over time, sort out the existing stock. At least, new owners would have the details of any stability deficiencies so it would be an incentive for the owner to get his machine up to spec before passing the problems on to someone else.

Blanket banning would only push the movement more underground than it is now.

Steve Kirkby
 
CAA Report

CAA Report

Steve maybe this will help in your report, its a past thread describing an RAF fatality in the UK, it contains the link to a CAA report decribing the accident. The CAA inspector did a pretty good job of investigating the accident and states the characteristics of the gyroplane and recommends the use of a HS.

UK RAF Fatality thread
 
Inherently unstale

Inherently unstale

In reply to the above ascertion by Doug. I do not agree at all. The Cricket has a small prop, like original Bensons. It is not a high performance machine. Hundreds have flown over many years with no problems. I susect that the thrust line is not a million miles out.
Please don't scare our potential gyro pilots too much. The Air Command achieved that !

Brian
 
Brian, many unstable machines have been flown for many years and many will continue to be flown for many years to come. Many people have died that would not have had they been flying stable machines. I have flown both unstable and stable machines. I have a choice as to which one I fly. I will continue to fly stable machines.
 
You Sure!

You Sure!

Brian, are you saying that Bensen's are stable machines! Long before there were Air Commands, Bensen's were killing people. The intent isn't to scare potential gyro pilots, it is about educating them so they can stay alive and enjoy gyro flying with out any unintended adrenalin rush.

Also why are you so sure that the Cricket thrust line isn't way out of whack. It has been demonstrated, by the GyroBee for instance, that you can not eyeball the thrust line/vetical Cg relationship. If you want to sustantiate your claim then I would suggest you find a Cricket and go thru the vertical Cg determination procedure. I'm sure someone here can supply it. Even then it is very possible that any two machines will check out different unless they are constructed exactly alike.
 
The Bensen had an awful safety record. I joined PRA in mid-1969 and have been reading PPO and PIO accident reports ever since, starting with the first issue I received. It was not unusual to have a couple such accident reports in a single issue. Most Bensens had a thrustline enough above the CG to allow PPO after a few cycles of porpoising, thanks to the low-mounted metal gas tank, heavy wheels, short mast and light blades. The fact that the prop was only four feet long was not enough in itself to make them stable.

Yes, the Air Command made a bad situation worse. My comments about flying unstable gyros come from a number of years of owning and flying a stock 1985 Air Command, with inverted engine and no HS. The CG was a good 5" below the thrustline, even without the pod, brakes and auxiliary tanks. I'm still alive, thank you, but there were a few flights in turbulence where that outcome was far from assured. The simple addition of an HS, even when the low seat and inverted engine were retained, made an astonishing improvement in this craft's handling.

The flight behavior reported at the beginning of this thread is characteristic ONLY of gyros that are statically unstable in pitch. A fuselage pod can contribute to instability in a craft that's otherwise benign... especially at higher speeds. If the aircraft is to have a pod, its configuration must assure stability with the pod mounted.

I have every intention of scaring the heck out of gyro pilots about this issue. Entirely too many people think that stability is some low-priority option on an aircraft (like metalflake paint, perhaps). There is no excuse for flying Dark Ages aircraft when we know better.
 
I came in the forum about 3/4 years ago and did not know anything, I wasn't scared of the subject and did my home work looking to fly on recommended machines, so far so good . . .
Warnings are good! The police every now and than have shows with grusome pictures to wake people up for the consequences. It does not scare people out of driving!
When a machine sucks . . .it sucks! (Just like the PRA . . .heheheh) The Devil . . .it was The Devil . . . .:D
Heron
 
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