Sparrow Hawk N430HS - Texas

Tyger

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Dave, you certainly can land them that way, but you often don't really need to. That's why Paul Salmon has new students leave some power in when landing (idk how much you watched of his video, posted above).
If you leave some power in till you touch down, you don't have to be as precise in flaring, but you will then have some extra forward speed on touchdown. It's not really a problem on a smooth runway, and certainly preferable to flaring too slow and high and then... wham!
 
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Andino

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Don't all gyros land at the <= 5mph groundspeed touch downs? My training and gyro experience is limited to MTO, AR-1, Apollo and SC M912... Always touched down for landing in the SC with little to no forward groundspeed.
I was probably a tad imprecise, apologies. I did not mean to imply that certain gyroplanes are supposed to be landed fast, but that too many pilots seem to do so. You apparently received good training! (y) Not everyone does...
 

Rowdyflyer1903!

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What is the minimum controllable airspeed? At what point do you lose rudder authority on a non powered vertical decent? Those numbers should be in the back of a pilot’s mind during landings. A quickly arrested landing is different from a 5mph roll out.
 

Vance

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What is the minimum controllable airspeed? At what point do you lose rudder authority on a non powered vertical decent? Those numbers should be in the back of a pilot’s mind during landings. A quickly arrested landing is different from a 5mph roll out.
The Airplane Flying Handbook (FAA-H-8083-3A) states that the term flight at minimum controllable airspeed means a speed at which any further (1) increase in angle of attack or (2) load factor, or (3) reduction in power will cause an immediate stall.

It appears to me that “minimum controllable airspeed” as defined by the FAA doesn’t apply to gyroplanes.

In a power off vertical descent most gyroplanes that I have flown will lose rudder authority and some will spin.

I feel that should not be part of a landing sequence when flying a gyroplane.

I feel it is important to understand how dramatically the rudder authority is reduced as the indicated air speed gets low.
 

Rowdyflyer1903!

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Again I respectfully disagree and this issue perhaps is a matter of semantics.

For example in Magni’s Pilot Operating Handbook, minimum controllable airspeed is defined by the speed which the rudder is effective or not.

There is a point on a zero airspeed vertical decent where rudder authority is lost. Forward stick and a regain of airspeed is required to regain rudder authority with no power applied or available. This number should be put to memory and understood.

Help me out here if I am wrong about this. What is the indicated airspeed found in Predator where the rudder authority is lost?

Would one dare to make an engine out approach at less than best glide speed? Specifically in the final moments before flair. During the period which the forward speed is being arrested and the time the nose is in the air, what speed would you like to be before setting the nose down?

Seems to me a little rudder authority might useful at that critical point. I realize it takes longer to describe than to do.

A touchdown at too slow a speed, although something fun to practice and impressive to watch, might add additional risk until ground control is assured.
 

WaspAir

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You shouldn't be landing from the avoid region of the H-V diagram. If you come in under it, a zero roll landing is pretty routine.
 

Vance

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Again I respectfully disagree and this issue perhaps is a matter of semantics.

For example in Magni’s Pilot Operating Handbook, minimum controllable airspeed is defined by the speed which the rudder is effective or not.

There is a point on a zero airspeed vertical decent where rudder authority is lost. Forward stick and a regain of airspeed is required to regain rudder authority with no power applied or available. This number should be put to memory and understood.

Help me out here if I am wrong about this. What is the indicated airspeed found in Predator where the rudder authority is lost?

Would one dare to make an engine out approach at less than best glide speed? Specifically in the final moments before flair. During the period which the forward speed is being arrested and the time the nose is in the air, what speed would you like to be before setting the nose down?

Seems to me a little rudder authority might useful at that critical point. I realize it takes longer to describe than to do.

A touchdown at too slow a speed, although something fun to practice and impressive to watch, might add additional risk until ground control is assured.
I don’t intend to diminish your questions; I am puzzled by them and trying to relate them to my gyroplane flying experience.

What would I do with rudder authority in a zero airspeed vertical descent?

Yes, I would dare to make an engine out approach at less than best glide speed and I might do it if my landing spot is too near.

The airspeed indicator falls to zero well before I lose rudder authority in The Predator or any gyroplane I have flown.

Some airspeed is required to have rudder authority during an engine out landing.

If I don’t have a way to quantify the indicated air speed where I lose rudder authority; why should I remember what the number is?

In what situation have you needed more rudder authority than you had available in a gyroplane?
 

Rowdyflyer1903!

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No, sorry
I never meant to imply such a decent to landing should be done ( at zero airspeed) I did see such at an air show in Texas which I was the Show Boss. The pilot was flying a Bensen and had installed a bolt which was too long. He was demonstrating a vertical decent with a peddle turn. The rudder installed bolt got forced over the top of another resulting in the rudder being jammed. The EMS and the fire trucks were below me. As the aircraft descended through 400’ and he had not recovered, I told the emergency people to roll because he was crashing. He went in into a thicket of Mesquite trees, scattering tree limbs and parts like a large lawn mower. He survived with compression fractures in his back.

My example of rudder inefficiency at certain airspeeds related to Minimal Controllable Airspeeds in as we know is something not very thought of but it is a thing. Also as a few fixed wing aircraft such as a Stinson will not stall but that does not mean it will not develop a sink rate which can be deadly. My statement about not approaching a landing with out the power of an engine at less than best glide speed was meant to say in a power off glide to landing in a Gyroplane will or can result in a harder and injurious landing. That is all.

The point I was attempting to make is there is a condition where at a diminished airspeed, the rudder no longer will affect the pointing of the direction of the fuselage.

As was stated, at times during a vertical decent at zero indicated airspeed a slow turn will commence. I am guessing this is despite how the rudder is deployed.

This in itself is interesting because that turning motion has to be from a force from somewhere. A fixed wing in a spin is not fully stalled, despite popular belief. The upper wing is imparting lift otherwise it would fall like a rock with no turn to it.

We see the skilled among us, with great trust in their skill, engines and machine, float along the runway, engines Screaming and with the Gyroplane standing on its tail. Fine but risky if the engine hiccups. I expect the rudder is deployed to counter the torque of the engine and at the time the engine quit, what happens? A roll? A nose swing one way or the other? Does it drop straight? Quite doubtful. With no directional control you are at the mercy of the elements.

A Gyroplane indeed has minimal controllable Airspeed.

I do feel I owe the group an apology as I drifted off topic.

The original question was why was the aircraft on the upwind and left side of the runway ( which can be explained by blade sail, retreating blade stall by too much speed and not enough rotor rpm). But why was it laying on its right side?

I offered an alternative which was not accepted by several. I got off topic trying to support my premise. That premise being the pilot had deployed left rudder to counter the drift ( a common fixed wing technique ) but has too much aft stick, generating so much drag, a decent to the runway occurred. The aircraft being in a crab then contacted the runway with the right main and right side of the fuselage. This is where the aircraft came to rest, on its right side not the left.


I am guilty, very guilty of, as it has been said, of over thinking things. I want to know every nuance of the machines we love. I am consumed by them.

How may times has the common accepted explanation of science and physics been wrong or at least needs tweaking. Right now at this very moment we still are trying to figure out how airfoils work. Bernoulli is a partial answer yes. Viscosity is a partial answer yes. There is so much more to learn.

I pray this group never tires of a good, honorable and respectful debate.
 

Vance

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I pray this group never tires of a good, honorable and respectful debate.
I did not think of it as a debate Rowdyflyer 1903.

I did my best to answer your questions.

I even asked some of my friends about your questions because they could better look through the window of an experienced airplane pilot.

This helps me be a better gyroplane flight instructor and I thank you for your help.

I almost started another thread under training to better address your questions.

I am always happy to answer your questions.

I apologize if it felt like a debate to you.
 

Rowdyflyer1903!

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Lol Airline pilots don’t know how to use rudders either. The rudders and ailerons are inter connected. I was fortunate enough to get some time in an actual Airbus 320-??? million dollar simulator. The Instructor Pilot had to remind me to keep my feet flat on the floor. He loaded up the Checkerboard Approach. (There can be only one ) Google it for some hair raising footage. I landed it twice but sucked on taxi. The little steering wheel off to the side totally baffled me. This is back when I had a disposable income. Speaking of that not going to Bensen Days this year.
 

Doug Riley

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Those of us fossils who learned on hand-prerotated gyrogliders got pretty intimate with our rotors. It's a valuable skill even in a gyro that cost more than my first house.

There's a FEEL to a full-RRPM rotor -- and it's different from the feel of a rotor that's not up to speed. A rotor tach is nice, but unnecessary once you develop the feel. And you really, really need to develop it.

This feel is the resistance of the rotor to forward progress when the stick is fully aft. This happens as the nosewheel lifts off the deck. Once you reach full RRPM with the stick aft, the gyro VERY noticeably slows down (from the drag, of course). The sensation is like rolling into deep mud in your a car. The power should be at or near wide-open -- increase it if not. Then ease the stick forward gently. This will release the gyro from the "mud" and allow it to pick up airspeed. Don't ram the stick forward -- ease it, please.

Far from "rotating" nose-up as a FW plane does, a gyro needs to "un-rotate" once it reaches full RRPM, preliminary to lifting off. It then levitates, as Vance said, with little or not further rotation, when it's ready.

Some light, high-powered gyros can be forced off at full power at a high nose angle. But beginners shouldn't be flying hotrods and, if they do, they should not try this sort of show-off maneuver. Lift off from a nearly nose-level attitude.

I cringe when I hear about neutralizing the stick before the rotor is wound all the way up. That is a sure-fire recipe for overspeeding the aircraft to the point of blade-sail. The stick should be at, or very near, the aft stop until RRPM is full -- and you should be able to detect that condition without a rotor tach.

I also cringe when I hear something like a Sparrowhawk referred to as a "gyrocopter." A "gyrocopter" is a 1960's bunt-o-matic collection of three 2x2 tubes, a target drone engine and plywood rotor blades.
 

Rowdyflyer1903!

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Excellent way of describing the feel. I can see Ken Brock right now in my mind nodding his head. 200 and go knows not this.
 

Andino

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I cringe when I hear about neutralizing the stick before the rotor is wound all the way up. That is a sure-fire recipe for overspeeding the aircraft to the point of blade-sail. The stick should be at, or very near, the aft stop until RRPM is full -- and you should be able to detect that condition without a rotor tach.
Yes! Design should support optimal technique, but it rarely does with gyroplanes. (Why this rampant aversion to flexshaft prerotators which allow aft stick 200+ RRPM?)
 

Doug Riley

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"Design should support optimal technique." A brilliant distillation of good (and rare) gyro design goals.

While we are designing to allow good technique, please build the protator to permit its remaining engaged as you ease the stick forward to pick up airspeed. This not only adds RRPM, but also governs down the engine RPM, making overrunning your rotor even less likely.

I had a Wunderlich prerotator for several years before another gyronaut pointed out that keeping it engaged longer was possible. I'd been releasing the prespin once I got through the rotor-all-the way-aft stage, then reducing throttle to begin my speed run without overunning the rotor. That was wasting some the Wunderlich's potential.
 

FlintHelo

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"Design should support optimal technique." A brilliant distillation of good (and rare) gyro design goals.

While we are designing to allow good technique, please build the protator to permit its remaining engaged as you ease the stick forward to pick up airspeed. This not only adds RRPM, but also governs down the engine RPM, making overrunning your rotor even less likely.

I had a Wunderlich prerotator for several years before another gyronaut pointed out that keeping it engaged longer was possible. I'd been releasing the prespin once I got through the rotor-all-the way-aft stage, then reducing throttle to begin my speed run without overunning the rotor. That was wasting some the Wunderlich's potential.
Just a guess, but I'd expect the complexity, weight, and cost factors of such a mechanism to be prohibitive. I'd also think a fail safe mechanism such as an over running clutch might be needed. Imagine this setup being inadvertently activated in flight by pilot error or mechanical failure.
 

Doug Riley

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The mechanism I described has been standard on Wunderlich prerotators for decades. I only learned about its full abilities at a flyin in 1990, making me a late-comer 32 years ago. I employed that keep-it-engaged technique from then on.

The hydraulic prerotator on my tandem Dominator also was capable of continued engagement throughout the takeoff run. That's not surprising, since the upper end on each of these prerotators is the same: an automotive-starter Bendix drive, with a built-in overrunning ratchet. That's in addition to the disengage spring in the actuator handle on the stick.

If you're really paranoid, you can secure the Wunderlich shaft housing (=a rubber hose) with a a little twisting pre-load, so that the housing itself acts as a disengagement spring. I do that with my Wunderlich.
 

Andino

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Just a guess, but I'd expect the complexity, weight, and cost factors of such a mechanism to be prohibitive.
While the flexshaft is more expensive and may be slightly heavier than U-joints/driveshafts, I believe that the flexshaft (if properly greased periodically) has a longer service life. Many companies use them (RAF/Sparrowhawk, Sportcopter, Magni, Xenon). It's a well-proven system which allows for a less risky (and shorter) take-off.
 

Vance

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It is possible that the engineering departments of Auto Gyro and ELA preferred the compromise they chose because they felt it was a better idea.

Based on what I know about mechanical engineers; it would be hard for them to imagine someone screwing up something so simple and straight forward as the takeoff procedure in a gyroplane.

Follow the procedure the in the POH and it is very straight forward and easy to teach.

The problem might be that the pre-rotation procedure is so simple that CFIs move on too quickly and don’t spend enough time with the why of each step.

Each time this subject comes up and people try to explain it; it is quickly apparent that many pilots have misinterpreted the instructions.

When I watch people at fly-inns; it is easy to see many have modified the takeoff procedure to “improve” it. I ask them about it and they say “that is not necessary and it is too hard on the pre-rotator to follow the POH.”

A client of mine who hit his empennage in a rushed takeoff had a flex drive pre-rotator and he had been taught in The Predator that allows continued pre-rotation with the cyclic rearward and received further training in his own aircraft.

RAFs and SparrowHawks have a typical number of takeoff accidents from mismanaged takeoff procedure.

This thread is about a Sparrow Hawk with a flex shaft.

Saying a flex shaft is better doesn’t make it so.
 

Tyger

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While the flexshaft is more expensive and may be slightly heavier than U-joints/driveshafts, I believe that the flexshaft (if properly greased periodically) has a longer service life. Many companies use them (RAF/Sparrowhawk, Sportcopter, Magni, Xenon). It's a well-proven system which allows for a less risky (and shorter) take-off.
And if you ever do manage to mess up your flex cable, getting and installing a new one is ridiculously simple.
 

GyroChuck

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The original flexshaft was repurposed from a vibratIng machine for concrete. The recommended lubricant is chain oil. But any type of lubricant seems to work well.
 
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