I've got a challenge for ya

[Hognose]

Didn't that hightly publicised cross country supposedly "across the states" flight a few years ago get scrapped because of similiar issues?

The only flight I can think of that comes close to your statement is Chuck Feil's "Spirit of American Youth 2000" flight to all 48 states in an RAF. And Chuck completed the flight successfully.

https://www.chuckfeil.com/vfaPublishing/say2000/updates.htm

Chuck also got me hooked on gyros with some help from Dofin Fritts.

cheers

-=K=-

 

[mcbirdman]

Just remember you can be good at something but not good FOR something also.

Kevin, I am not sure why you quoted my question as a statement.

I was asking because on Norm's forum I seemed to remember reading some information that left the impression that they were "frazzled". By Harry's account 3 people, one worn out, 2 accidents and 4 aircraft used for only 2 completions. I guess I see why it isn't talked about that much though.

Thom, it takes a good pilot to control these machines and many like you have stood there thinking they were good enough. The main reasons you just can't agree with me on much more than that - truly would leave you little reason to keep tinkering with something that can't be fixed with bandaids as long as the same design flaws are still there. So much time arguing about something that is akin to doing the same experiment over and over is just not my interest. I have family and feel the responsibility to educate and protect myself as much as I can while pursuing my dreams. For me the safety of a design is the first consideration. Everything else is second but eliminating or avoiding as many negatives in a design as possible to make me less of a design test pilot and more of a pilot that just happened to build the machine should make flying far less riskier.

I anticipate that the excitement I get with flying a stable machine will be equally matched with the confidence and the satisfaction knowing that I am doing less flight testing than mechanical testing. I don't claim to be a good or great pilot. I am just not going to expose myself to additional risks without good reason. I cannot see any good reason for accepting any aircraft with significant flaws or shortcomings by comparison or known history.

Being a good pilot doesn't prove design. If there are gyros out here that others have let their friends fly without worry and you have a design that you know wouldn't come back from the first such flight - then you know what I say is true. It just happens that you have such a machine and this automatically has to put us at oposite ends. Its kinda hard to say you want safety and then go to buy a machine that in nearly every way goes against the aspects that have made gyros safe. This includes everything from the stability tests that apparently they won't pass to crashworthiness to pilot workload. You are fast approaching the next phase where your decisions are going to dictate the total risk you accept. Soon you will be another RAF pilot.
Soon I will be a Little Wing pilot. Two different schools of thought. Two different directions. Two different histories.

You are wrong again. We didn't finally agree on something. We both agreed that flying gyros is important enough to pursue. We both knew that about each other from the beggining. We also both know that we only have the best wishes and hopes for each other for safe enjoyable gyro flying. Take care Thomm and all. Merry Christmas to ALL. jtm

 

[Harry_S.]

The only flight I can think of that comes close to your statement is Chuck Feil's "Spirit of American Youth 2000" flight to all 48 states in an RAF. And Chuck completed the flight successfully.

https://www.chuckfeil.com/vfaPublishing/say2000/updates.htm

Chuck also got me hooked on gyros with some help from Dofin Fritts.

cheers

-=K=-

Thanks Kevin for correcting my boo-boo. In my post above I put the pilot as Chuck W. and it shoukd have been Chuck F.

Chuck F. has accomplished some fantastic photography while flying his "stock RAF" solo. Photography buffs would easily appreciate any of his books.


Cheers

 

[Steve McGowan]

All the gyro's will pitch, roll and Yaw at Mentone (anywhere) when the wind is rolling.. Standing on the ground you may or not be capable to see it..

Coming across the road with speed, Logan at 120+ and I'm at 110+ for a fly by.
The machine is workin,, so are we....

And if Ya don't believe it,,, GET IN !

 

[JByrd]

You fellows would argue over whether or not a (fresh) banana has a yellow peel.

I try to see some technical merit to the discussion but it seems to largely be buried in personalized comments.

Notice I said fresh banana...

The discussion is so subjective that it is kind of like the definition of a good dog.

There was a comment a while back by a respected person in this business who suggested using an already established set of criteria for characterizing stability and control. It is printed in the past issues of the PRA magazine. I personally like that approach. It follows a standard that I think most everyone can use and then begin discussing individual results from a common point of reference.

Jim B.

 

[Harry_S.]

Jim B., If their machines ALL pass the stability tests...then what are they gonna discuss and/or argue about?!

My momma used to say..."Men, they're not satisfied unless they're arguing about something." She knew whereof she spoke...mom had six boys; no girls.


Cheers

 

[JByrd]

Hi Harry,

Your mom was a smart lady. She knew a lot about people. I hope she is still around for her wisdom.

Jim B.

 

[dragonflyerthom]

What amazes me sometimes is when I hear my dad in some of the wisdoms I am passing to my grandchildren. I was 25 or 30 years old when I realized just how wise my dad really was. When I was a teenager I thought he was the dumbest person on earth. Surprising how smart he became. LOL Parents don't ya just love em?

 

[Steve McGowan]

Edumacation

Edumacation

Is very Xpensive,,, either you have time or the money that pays for it.

Arguing has a lil to do with it,, but mostly the ones thats doin it,, well to say the least don't have a quarters worth.

And most of the folks will use the Nanner for something else...

The first Ass-Whippin I got in the Marine Corps,,
I told the DI my Moma hit harder than he did....Uh HUH !!!

It tickles me to be called a White Elephant, Color Blind, Bass Akwards or
just plain Stupid....

My Theory is,,,,,,,

Talk is Cheap---Very Cheap,,,,,
Less you fly onea these things,,
built a Dozen or so,,, trashed as many...can hover 6" off the ground without anything under Ya...and Defy Gravity...

I'm just glad I don't have to prove anything.....

I'm too Damned Old and Ugly

Have a GREAT X-Mas and SAFE New Years

me&BOO

 

[Chuck_Ellsworth]

Steve, please don't get upset with this question, but how do you manage to trash your machines?

Or are you just kidding about trashing a dozen or so?

The reason I'm asking is it seems weird that people have so many accidents flying these things.

Chuck E.

 

[Steve McGowan]

No Problem Chuck

No Problem Chuck

Just bein Young and Dumb,,

Stupid, arrogant, head strong, and NO INSTRUCTION Available at the time on an open style trainer for a Bensen type gyro..
( I have trashed 6)... Hopefully NO-MORE

NO REASON for anyone to go thru what I did.....

Instructions ain't cheap,,, But it beats the hell outta rebuilding a machine or possibly getting killed trying to train yourself. :twitch:

You will learn more from an instructor in 1 hour,, than by yourself in 10...:der:

Other Words,,,,, GET INSTRUCTION:yo:

When Your Dumb,, YA GOTTA BE TUFF...:twitch:

steve

 

[Aussie_Paul]

Well said...

Well said...

Just bein Young and Dumb,,

Stupid, arrogant, head strong, and NO INSTRUCTION Available at the time on an open style trainer for a Bensen type gyro..
( I have trashed 6)... Hopefully NO-MORE

NO REASON for anyone to go thru what I did.....

Instructions ain't cheap,,, But it beats the hell outta rebuilding a machine or possibly getting killed trying to train yourself. :twitch:

You will learn more from an instructor in 1 hour,, than by yourself in 10...:der:

Other Words,,,,, GET INSTRUCTION:yo:

When Your Dumb,, YA GOTTA BE TUFF...:twitch:

steve

....Great post Steve.

Aussie Paul.

 

[gyrogreg]

"Buntover" is slang for PPO?

"Buntover" is slang for PPO?

Posted Dec 13 -----------------
Buntover is slang for POWER push over. It is impossible for a CLT or LTL gyro to buntover. -------------------------

Hi Ron! Sorry for such a late post on this thread, but I don't find time to keep up with everything on the forum. Perusing, I saw your comment above. Doug Riley responded a bit to this subject, but I wanted to clarify this:

IMHO, you have the slang backwards. A "buntover" is not the slang! "Buntover" is the general term that includes the subset of what people like to refer to as "PPO". "PPO" is sort of slang, because it refers to the visualization of a HTL pushing the gyro over when the rotor is unloaded. The "PPO" visualization is technically incomplete - and this incompleteness leads to possible dangerous misunderstandings and misplaced confidences! When people limit their understanding of what a "buntover" is, they misunderstand what can really cause a "buntover". The "PPO" visualization of a buntover invites the same assumption you inferred in your post – only an HTL can buntover! A "buntover" (whether a PPO, or a "Drag Over", or whatever) is the result of the RTV being forward of the CG - in that particular flight condition (Power/Airspeed). If or when the RTV is forward of the CG, it doesn't even take "unloading" of the rotor to initiate a buntover. All it takes is a decreasing G-Load that the pilot is unable to immediately correct. When the RTV is forward of the CG, the aircraft is G-Load unstable. That means that a pilot uncorrected reduction of G-Load will cause the gyro to progressively decrease it's G-Load (nose pitching downward) into the start of a buntover. If the pilot is unable to correct this decreasing divergent G-Load, the gyro will buntover!

"PPO" is just a form of, albiet a common form of, a "buntover". But, it does not necessarily require a HTL to buntover - a HTL "buntover" is often termed a "PPO" just because it is easy to visualize the high prop thrustline pushing the nose over when rotor drag is reduced! This is the easy and over-simple way that traditional buntovers have been described in the past - mostly so most people could appreciate and accept what is happening. But, this PPO mechanism, this incomplete "buntover" mechanism, IMHO, has led to too much misunderstanding of what a "buntover" really is and what makes a gyro able to buntover! It is technically wrong, and possibly even dangerous to promote the concept that “It is impossible for a CLT or LTL gyro to buntover.”

An "unbalanced" HTL can certainly contribute to a "buntover". This is because an "unbalanced" (unbalanced by a proper HS reacting to propwash and airspeed) HTL is likely to have the RTV forward of the CG! (The RTV forward of the CG is what makes the gyro capable of a "buntover" - not necessarily a HTL only!) And, a "buntover" is not necessarily always a "PPO"!

What else, besides an "unbalanced" HTL can make a gyro – even a CLT or LTL gyro, or even one with a HS - susceptible to a buntover? As Doug and others often point out, any aerodynamic moment on the airframe that forces, in flight, the nose to fly lower than normal will move the RTV forward of the CG and make that gyro G-Load unstable - capable of a buntover! These things can include:

• a badly low offset airframe drag moment (draggy landing gear, etc.),

• large sloping windscreen that force the nose lower in flight,

• a suddenly reduced LTL thrust (power) that allows the nose to drop radically,

• an uplifting HS suddenly left unbalanced by a loss of LTL thrust! AND,

• an unbalanced HTL

Gyros can be made truly "unbuntable". But this is not simply done by avoiding HTL! LTL or even CLT does not, by themselves assure a gyro will not buntover! (The only thing a CLT or LTL assures is that the "buntover" cannot be easily explained by the loss of rotor drag!) Many other conditions need to be satisfied or balanced also! In simple form, ALL the static moments acting on the airframe - propeller thrust, rotor thrust, AND aerodynamic moments on the airframe and HS must be in proper balance (for all conditions of flight - power/airspeed/loading) in order to make a gyro unbuntable. These conditions may be satisfied on a few gyro models that are mentioned elsewhere in this thread! But, just being CLT is not the whole answer. And, IMHO, reliance on this over-simplified "prescription" to avoid buntovers will, and has lured others into unsuspecting misconfidences.

To me, it is the continuing popularization of the “PPO” misunderstanding of what a buntover really is - this "PPO" visualization that creates false confidences that can lead people unsuspectingly into fatal accidents (Remember the Adler fatality in 2002?)

 

[gyrogreg]

"Buntover" continued

"Buntover" continued

------------- (If) I did a zoom climb with it, and at the top of the zoom climb I leave the throttle wide open and push the nose over enough to unload the rotor, do you not think the gyro would likely buntover? I do. -------

Not necessarily, Ron. Unloading the rotor does not necessarily cause a G-Load stable gyro to buntover (or "PPO")! A G-Load stable gyro will strongly resist being "pushed over" to a zero G condition! A G-Load stable gyro will strongly resist even reduced Gs. A G-Load unstable gyro - unstable in that condition of power/airspeed - does not even need an "unloaded rotor" or "zero Gs" to initiate a buntover - the G-Load divergence of the unstable gyro will force it to zero Gs or lower! I’m not saying an RAF is normally G-Load stable, but with an adequate, HTL “balancing” HS, it may be!

For an "unbalanced" HTL, a sudden reduction of power at the start of a zoom push-over, might position the RTV aft of the CG to make it G-Load stable and prevent the buntover you propose is inevitable! On the contrary with the LTL that you endorse, a sudden reduction of power at the start of a zoom push-over in a LTL might cause the RTV to position forward of the CG, at the same time the nose suddenly drops and the RTV moves forward - and suddenly make that gyro very susceptible to a "buntover"!

Will all gyros "buntover" in a push over the top of a power zoom? I do believe gyros can be designed to survive this flight maneuver. But, it is not simply the avoidance of a HTL that is necessary. In fact, the opposite of HTL, LTL, can make a buntover at the top of a power zoom very possible or even likely! For instance, if, at the top of a power zoom, the LTL pilot suddenly reduces power (the traditional maxim is “Power Before Pitch”), the nose will drop radically - both from the loss of LTL thrust and the upward lifting HS! The sudden nose-drop (from loss of nose-up LTL thrust, and the initially up-lifting HS) can easily move the RTV forward of the CG! With the nose dropping quickly and the RTV moving ahead of and possibly further ahead of the CG (suddenly G-Load unstable), a buntover is text book likely - even in this LTL gyro!

I promote that no one should do steep and or high power zoom climbs. In this condition, the response of any gyro to unpredictable pilot actions may be unpredictable. But, IMHO, if the gyro would be PERFECTLY Power stable, and Airspeed statically stable, so as not to radically pitch the nose downward with any change in power, that gyro may possibly be safe to "push over" the top of a zoom! This may be so, because if the condition of power, or a change in power, does not cause the RTV to move forward of the CG, the gyro in this condition is still G-Load positively stable and WILL NOT BUNTOVER! Especially, since to "push over" at the top of that zoom, the pilot is actually moving the RTV further aft of the CG (stick forward) - more strongly G-Load stable! Any reduction of G-Load, including momentarily all the way to zero G, while the gyro is strongly G-Load stable, will cause an up-nose pitch response to both avoid the "buntover" and restore positive 1g quickly - In some gyros, quickly enough to avoid any negative results from even zero G at the top of a zoom!

How do we make a gyro so stable and incapable of a buntover (or "PPO"), even at the top of a zoom? Always the same answer! A properly designed and effective HS. This HS should minimize the effect of a HTL or LTL by "balancing" the offset prop thrust moment with the appropriate HS moment as a function of power (prop thrust). When this is done, no matter at what airspeed, the airframe pitch (nose up or down) will not change as a result of a change in power. This is the first static test and criteria in the gyroplane ASTM standard. The ability to remain G-Load stable at all power settings is one major reason for this ASTM criteria. There are other reasons for verifying POWER static stability.

There are three static stability flight tests everyone should flight test their gyro for. IMHO, all this arguing, and especially stability evaluation based on how it "feels" in flight, are completely wasted prose! Objectively flight TEST your gyro, with the three simple static stability flight tests, and you will know if it can buntover. The actual flight testing to the ASTM standards is probably easier and less stressful than all this writing and arguing on the forum. Test your gyro and report the results!

I do not propose that anyone try to push over at the top of a zoom! But, if I were going to see what would happen, I would certainly verify POWER, AIRSPEED and G-LOAD static stability first! (easy to do!) There are technical, “Sum of Static Moments” reason that it is difficult to make a LTL gyro meet the ASTM standard for POWER and AIRSPEED static stability at all combinations of power and airspeed - much less have NO pitch response to power changes! But, I have flown at least one HTL gyro that has a well balanced HTL to HS to show very little change in pitch with power changes! (It has been reported that the LW also meets this!) And, IMHO, a large enough and properly balancing HS on even a RAF might be less likely to "buntover" or "pushover" at the top of a zoom than most "unbalanced "HTL” or “LTL” gyros!

Synopsis:

• A "PPO" is just one form of a "buntover"

• "Buntovers" are what should really be of concern - all types of buntovers, not just “PPO”!

• HTL isn't the only gyro that can "buntover"

• CLT or LTL does also not assure a gyro cannot "buntover"

• HTL does not determine if a gyro can "buntover" or "PPO"

• CLT or LTL or HTL alone does not determine a gyro's safety!

• RTV forward of the CG determines if a gyro can "buntover" - G-Load stability.

• RTV position is a function of more than just prop thrustline. A good balance of all drag and thrust and lift moments on the gyro is required.

• The over-simplified visualization of "PPO" as the only form of a "buntover" can lead to misplaced confidences.

• Flight testing of the three static stability criteria is the simplest and most assured way to determine if your gyro can buntover!

• Never "push over" the top of a zoom - no matter how confident you are in your gyro! Just too many unpredictables and unknowns to take the chance!

Thanks, Merry Christmas and Happy and Safe Flying New Year,

- Greg Gremminger

 

[Steve McGowan]

I have a question for Ya,,

How the Hell do yall type a few thousand words on these pages..

GRACIOUS GUY'S.....It's all I can do to keep track trying to read it.

If Yall Pursue flying as much as writing on here..

Yall Gonna Be some FLYIN-ASSES

Happy New Year yall

Steve

 

[Passin' Thru]

I have a question for Ya,,

How the Hell do yall type a few thousand words on these pages..

GRACIOUS GUY'S.....It's all I can do to keep track trying to read it.

If Yall Pursue flying as much as writing on here..

Yall Gonna Be some FLYIN-ASSES

Happy New Year yall

Steve

:lol: :lol: :lol: ! Happy New Year!:yo:

 

[gyrogreg]

Misplaced confidence!

Misplaced confidence!

Throughout this thread and many others, I see a concept that might be dangerously establishing a misplaced confidence in the infallibility of your particular gyro.

A lot of people believe their gyro is "stable", or is "unbuntable"! Some mistakenly believe this simply because it is a high seater, or has a HS, or is painted blue! Some people believe this because it "feels" stable when I fly it! These are truly misleading confidences! Some people even do some static stability flight testing and find it meets the ASTM criteria.

But, the problem is that, just because a gyro might truly meet even the ASTM criteria at some power/airspeed/loading condition, that does not necessarily mean it will also be stable at some other power/airspeed/loading condition. Most gyros will meet the ASTM static stability criteria at lower airspeeds. But, we know for instance that HTL gyros, without a properly "balancing" HS, will likely become less stable, especially less G-Load stable, at higher power and airspeed conditions - this is where we see many of these configurations bunting over!

But, even a popularly respected stable design might have "corners" of the flight envelope, "corners" of the power/airspeed/loading envelope in which that gyro becomes unstable. A common such condition might be a radically LTL gyro at the flight envelope "corner" of low power and high airspeed. At low power and high airspeed, a LTL gyro, that normally depends on the LTL nose-up prop thrustline for G-Load stability, may be dragged nose-low at high airspeeds by draggy long landing gear and windscreen and an up-angled HS - when power is not applied at high airspeed! Anything that might cause a gyro to fly nose-lower than normal, positioning the RTV forward of the CG, might make that gyro capable of a buntover. The high degree of G-Load stability from a LTL gyro is attained by that LTL thrust! Take away that thrust, and that machine is no longer nearly as stable - in fact it might easily become G-Load unstable and capable of a buntover - especially at high airspeeds.

The point is one cannot simply claim their gyro to be "stable and safe" without also setting some limiting qualifications to this - such as Vne or some combination of power/airspeed/loading where it might not be so stable! It is no good to just simply state that my gyro is stable – need to set some conditions within which it is tested to be stable! For instance, one might legitimately argue that a standard RAF is perfectly stable. It may even flight test to be stable at 55 mph and normal MPRA (minimum power required airspeed) power. But, at some higher airspeed (some RAF instructors have suggested that would be about 75 mph), the standard RAF is no longer stable - "takes more skill to fly above 75 mph"! To me that would mean, that if a particular gyro is no longer G-Load stable above 75 mph, 75 mph should be the published Vne. (What is the published Vne of an RAF - and could this maybe be why there are buntovers in RAFs!)

To eliminate all dangerous "corners" of the flight envelope of a gyro requires a proper aerodynamic balancing of the static moments so as to maintain POWER, AIRSPEED and G-LOAD static stability to all those flight envelope "corners". Most gyros have flight envelopes within which they are truly "stable and safe". But, many gyros have power/airspeed/loading "corners" of their flight envelope beyond which they are no longer so stable and may be unsafely unstable!

Even when you perform the objective static flight tests, these need to be done at all power/airspeed/loading achievable "corners" of the flight envelope. People do not get into trouble when they fly within the safe flight "envelope". It is when they venture unknowingly beyond the safe flight "envelope" that they - surprise! - are in unrecoverable trouble!

Know the "corners" of your safe flight "envelope"! Just "feeling" or even testing your gyro to be stable at some comfortable flight condition, certainly does not assure your gyro will be similarly safe and stable at high airspeed, or high power, or some extreme combinations of power, airspeed and loading. Perform the static stability flight tests at all combinations achievable in your gyro. Identify the "corners" of your safe flight envelope, and then stay within those "corners" at all times"!

Then, when you make the statement that a particular gyro is safe and stable, or in "unbuntable", please be sure you know the flight "envelope" within which this is true. Please don't mislead yourself or others with unproven stability claims that should really be qualified by also identifying the limits in which this is true!

- Thanks, and have a safe flying New Year! - Greg Gremminger

 

[C. Beaty]

All vertical aerodynamic forces; tail lift, negative or positive, sloping windshield lift, negative or positive, rotor lift, negative or positive, can be resolved into single lift line. If the resultant upward force is ahead of the CG, the machine is tail heavy and unstable vs. angle of attack.

A tandem wing airplane is a good illustration. With 2 identical wings, the resultant upward force is at the midpoint of the distance between the two wings. If the CG is forward of the midpoint, the machine will have angle of attack stability and will always head into the relative wind. If the CG is behind the midpoint, the machine is unstable and will diverge.

As the rear wing is made smaller, the resultant lift line moves forward until we have a conventional airplane.

As the front wing is made smaller, the resultant lift line moves rearward and we have a VariEze.

Always, the CG must be forward of the resultant lift line in order to have angle of attack stability.

Any gyro that requires rotor thrust to prevent tumbling, obviously will tumble when rotor thrust is removed.

If it happens to be unstable vs. angle of attack, a small reduction of rotor thrust can initiate a compounding of the tumble effect.

 

[Harry_S.]

Those are great informative posts, Greg G.

I hope EVERYONE reads and understands the educated reasoning in 'em.


Cheers

 

[Harry_S.]

You fellows would argue over whether or not a (fresh) banana has a yellow peel.


Notice I said fresh banana...

I was going to comment on this the other day...but forgot.

Not to be argumentive Jim, but...did you ever hear the "Chichita Banana" (sp) commercial?! The line is : "When they're flecked with brown and have that special hue, that's when bananas are the best for you."


Cheers