Gyro-tech carbon fiber blades/RAF

eddie

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in my last post I never mentioned SC,why does this Kolibri person insist on making an issue out of all comments,and is always referencing and defending SC.



I had SC blades and I replaced them there were some things that I did not like but,I still think they are well made and way



overpriced,a lot of people like SC blades and there are lot of people that do not,so what. Kolibri your not going to get an argument from me.
 

Kolibri

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I had SC blades and I replaced them there were some things that I did not like but,I still think they are well made and way overpriced . . .
if it were that bland and simple, you'd be right, so what.
However you repeatedly changed your story about smoothness, and at the end accused SC of sending you poorly balanced blades.
Chuck Beaty then congratulated you on getting rid of what he insinuated as "
dangerous" rotors.

So, I'm calling B.S. on both accusations.
 

Vance

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I love the Sport Copter blades on The Predator.

I also love the wood blades on the Air and Space 18A.

My sport Copter rotor blades and hub bar will not see 1,700 flight hours because of corrosion. I will replace the blades and hub bar soon with Sport Copter blades and hub bar.

Some days they are smoother than others and have never been particularly smooth on The Predator. In my opinion her mast is too stiff and it is not the fault of the blades and hub bar.

They do not always fly at the same rotor rpm and putting numbers on their performance is outside my ability to duplicate conditions.

I did not buy a Sport Copter rotor head with its reduced offset so I have a lot of trim spring compared to my RAF blades.

I like everything I see about the Gyro-tech rotor system.

I prefer AN hardware.

I see nothing wrong with metric hardware for gyroplanes if they are designed for it.

There is a lot to learn about aviation hardware and the aviation way of doing things and I strongly suggest pilots learn about it from Aircraft Inspection, Repair & Alterations; an FAA publication. You will need an additional source if like most your gyroplane uses metric hardware.

I have only seen spherical rod ends fail if they are put in bending because their misalignment has been exceeded. In my opinion the forces in a gyroplane rotor control system are well below the maximum load capability of even the poorest quality rod ends. I prefer quality rod ends in good condition. I have seen gold colored quality spherical rod ends. If I find a bent spherical rod end I replace it rather than straightening it.

I would not fly a gyroplane without a preflight inspection and would not buy one without a careful pre buy inspection.

I do not feel the same about The Predator everyday and in my opinion anyone expecting consistency in my posts does not know much about gyroplanes or human nature.

I am familiar with a gyroplane accident caused by a negative pitching moment with
blades that were more flexible than my Sport Copter blades. I have seen no evidence of twisting in my Sport Copter blades but that is not to suggest it is not there; only that I haven’t noticed it.

My enthusiasm for sharing what I have learned with my friends on The Rotary Wing Forum has been diminished by a few people who want to pick a fight and debate things they don’t understand.
 

eddie

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Thank you Vance for your insight,I had considered leaving this forum because of the toxic rants,but then I read your post and realized that a lot of good people are here to collect information about Gyrocoptors and the vast marjority are intelligent enough that they see that type of a person for what they really are.
 

C. Beaty

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Vance;n1129183 said:
I have seen no evidence of twisting in my Sport Copter blades but that is not to suggest it is not there; only that I haven’t noticed it.
But you have without having recognized the signs. Stick force and necessary trim spring tension is an excellent measure of blade pitching moment and resultant twist, all else remaining constant.

Bensen wood rotors were over reflexed which produced a nose-up twist, causing the advancing blade to twist more nose-up than the retreating blade. This moved the rotor thrust vector nearer the pitch pivot and eliminated the need for a trim spring in most cases.

Rotor blades with a negative pitching moment cause the advancing blade to twist nose down more than the retreating blade and thus suppress cyclic flapping with the attendant increase of stick force and the need for a stronger trim spring. It’s like a built in swash plate that tilts the rotor nose down and if the negative pitching moment is sufficiently large, can cause reverse flapping.

No rotor blade is so stiff as to be unaffected by pitching moments; any blade 10-15 feet long will twist even if made from solid aluminum.
Rotor lift/drag ratio has nothing to do with stick force.

offset.JPG
 

Vance

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C. Beaty;n1129190 said:
But you have without having recognized the signs. Stick force and necessary trim spring tension is an excellent measure of blade pitching moment and resultant twist, all else remaining constant.

Bensen wood rotors were over reflexed which produced a nose-up twist, causing the advancing blade to twist more nose-up than the retreating blade. This moved the rotor thrust vector nearer the pitch pivot and eliminated the need for a trim spring in most cases.

Rotor blades with a negative pitching moment cause the advancing blade to twist nose down more than the retreating blade and thus suppress cyclic flapping with the attendant increase of stick force and the need for a stronger trim spring. It’s like a built in swash plate that tilts the rotor nose down and if the negative pitching moment is sufficiently large, can cause reverse flapping.

No rotor blade is so stiff as to be unaffected by pitching moments; any blade 10-15 feet long will twist even if made from solid aluminum.
Rotor lift/drag ratio has nothing to do with stick force.

Thank you for sharing your knowledge Chuck.

I have learned a lot from you.

I am trying to apply your information Chuck.

What does it mean to me to The Predator, my clients and me.

I have around sixteen hundred hours on my 30 foot eight and a half inch chord Sport Copter blades and have flown from zero indicated air speed to over a hundred twenty knots (138 miles per hour) indicated air speed.

I have flown from minus 500 feet density altitude to thirteen thousand feet density altitude.

I have flown as light as eleven hundred pounds and as heavy as fourteen hundred pounds gross weight.

I have seen rotor rpm as low as two hundred eighty and as high as four hundred.

My glide ratio is typically around four to one.

I have not been able to achieve more than two point one Gs or less than point six Gs when I have put two different G meters on her.

The stick pressure is higher as the rotor sees more mass. In a sustained steep turn I am pulling back fairly hard on the cyclic.

I have a Rotary Flight Dynamics slider rotor head and control system with standard offset.

The only thing I have done that I found disquieting is I had to use forward pressure on the cyclic at around 30kts in a zoom climb to get the nose down. I have only had this happen once in seventeen air shows. Typically she noses over near the top on her own.

I am about to replace my Sport Copter blades and hub bar with another set of Sport Copter blades and hub bar because of corrosion and hangar rash.

My computer is acting badly so this is all from my poor memory.
 

Vance

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eddie;n1129189 said:
Thank you Vance for your insight,I had considered leaving this forum because of the toxic rants,but then I read your post and realized that a lot of good people are here to collect information about Gyrocoptors and the vast marjority are intelligent enough that they see that type of a person for what they really are.
When I think of all I have learned here and the bad information I have dodged; I feel I have an obligation to pass on as much as I am able to articulate.

As a Certificated Flight Instructor I am tasked with making aviation safer and that means more to me than some unpleasant person'’s opinion of me.

It is fun to read about the progress many of the forum members are making with their gyroplane adventure.

I consider you a friend Eddie and value your posts.

I feel the Rotary Wing Forum would be diminished if you posted less.
 

C. Beaty

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Vance;n1129192 said:
What does it mean to me to The Predator, my clients and me.
With rotorblades having a nosedown pitching moment, there will be some airspeed where you will not be able to pull out of a dive. But that airspeed can only be determined by testing. If the stick starts moving rearward with increasing airspeed, you’re on the verge of it.
 

Vance

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Thank you Chuck.

That has not happened yet or at least I have not noticed it.
 

Kolibri

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eddie, grow some thicker skin. You actually accused Sport Copter of not sending out balanced blades as they claim, in effect calling them liars.
So, don't whine about my "negative" posts because I called you on it.
I've already offered conclusive evidence that your blades could not have been so out of balance from the factory to need 6" of lead solder in one of them.

You lament the +$2,000 loss on your SC blade resale, yet didn't see that such was over half-way there to completing an SC upgrade.
Meaning, you could have dumped your lousy RAF torque tube, mast plates, and trim system for something beautifully engineered, tested, and safe.
If any RAF needs that, it's your 230hp turbo. There's no way I would fly such a powerful engine on OEM RAF rotorhead parts.

"
The tragedy of life is not that man loses, but that he almost wins."
— Andy Andrews, The Traveler's Gift




Finally, if a lack of money is the only thing keeping you from replacing your original RAF control rod ends (which not even RAFSA uses any more, having at least gone to the decent Alinabal PM-6-G), then I will buy a set of Heims for you as a gift because I care about your life.

Barring that, why not at least remove each of your ten control rod ends and carefully inspect them for corrosion and cracks?
If they're original (as they certainly look) then they've been on for many years and some 700 flight hours.


____________
Sure, Vance, and when you take delivery of eddie's Sport Copter blades, confirm their balance (and what extra weights were present) and report back about this oddity.
Maybe eddie will also include the original pitch block for you to compare with the replacement, and illuminate for us that mystery, too.


I have only seen spherical rod ends fail if they are put in bending because their misalignment has been exceeded. In my opinion the forces in a gyroplane rotor control system are well below the maximum load capability of even the poorest quality rod ends. I prefer quality rod ends in good condition. I have seen gold colored quality spherical rod ends.
https://www.rotaryforum.com/forum/eq...83#post1129183
One could make such a general claim for nearly all mechanical load forces, thus "justifying" cheaper parts.
The control rod ends in eddie's photos last June were not merely gold colored, but the same unique housing shape of RAF's Grade 0 crap.


As a Certificated Flight Instructor I am tasked with making aviation safer . . .
Great, then, in this particular matter stop hedging and act like it.


____________
Replying to and quoting Chuck:

A zero pitching moment blade will not maintain a constant cyclic flapping angle as airspeed increases because the blades are blown back.


As forward speed increases, cyclic flapping also increases and the rotor tip plane axis in effect blows back . . .
11-12-2008, 03:06 PM
http://www.rotaryforum.com/forum/sho...5&postcount=14
Thus, the stick will move forward to compensate for the increased AofA. At some AS, the rotor tip plane axis has tilted back enough from blowback effect to null out previous trim pressure, meaning at that AS the gyro doesn't need any nose-up trim at all. If the trim system broke at that AS, you wouldn't even know it (at least from a pitch axis). This adds some inherent safety at that AS (and only that AS), and acts sort of like a speed limiting device. But at what price? Draggy AofA. Also, a 0 Cmo blade does not eliminate the need for a trim system, as any AS slower than its equilibrium AS will still require nose-up trim because of the offset gimbal head.

Now, if a blade has a nonexcessive amount of negative pitching moment such could be generally balanced to compensate for the blowback effect on AofA at increasing AS.



The nosedown twisting at least partially compensates for the airspeed differential [i.e., blowback effect]
11-12-2008, 03:06 PM
http://www.rotaryforum.com/forum/sho...5&postcount=14
. . . rotor blades that are either tail heavy or have a negative pitching moment have some self actuating behavior. Like built in power steering.
04-05-2016
https://www.rotaryforum.com/forum/ro...455#post905455
Thus, the stick neither moves forward or back. This seems to be what Sport Copter pilots experience. I do.
The AofA stays (within safety margins) as flat as it can be, and reducing drag and increasing performance in all ranges (takeoff, climb, cruise, glide, and landing).
Also, the stick does not become lighter at higher speed, requiring the lessening of trim along the way.


The price for that? Heavier trim pressure throughout all AS, but that's what trim is for. It's not as if the pilot must hold stick pressure himself.
Once level flight is achieved, trim it out and you can thereafter leave it alone as it will remain pretty constant at all airspeeds.



No rotor blade is so stiff as to be unaffected by pitching moments; any blade 10-15 feet long will twist even if made from solid aluminum.
https://www.rotaryforum.com/forum/eq...90#post1129190
OK, but some blades are stiffer than others, which would lessen the tip twisting.
I.e., you can't throw out some negative Cmo and then declare that all such blades regardless of construction will act equally.


Within a reasonable range of zero to somewhat negative pitching moments, all is safe. It really boils down to taste.
I personally don't mind setting nose-up trim to counteract blowback and thus enjoy a flatter AofA for increased flight performance.
I think the idea of maintaining a more constant cyclic flapping angle through a bit of negative pitching moment has merit.
In Sport Copter's case it's certainly not been "dangerous". If the stick is not moving back, how could it be dangerous?


With rotorblades having a nosedown pitching moment, there will be some airspeed where you will not be able to pull out of a dive.
But that airspeed can only be determined by testing. If the stick starts moving rearward with increasing airspeed, you’re on the verge of it.

https://www.rotaryforum.com/forum/eq...95#post1129195
Thank you, Chuck, you make my point quite readily, that such an AS "can only be determined by testing" and not through computer analysis alone.
Not all negative pitching moments are dangerous, and I continue to believe that your sweeping implication to the contrary was unfair to Sport Copter.


__________
For those with (or considering) Sport Copter rotor parts on the RAF2000, I've composed a handy guide to help.
SC rotors fly very differently than RAF's, and trim forces will depend on which rotorhead you're using.

Kolibri's tips on adding Sport Copter rotors to the RAF2000

https://www.rotaryforum.com/forum/ki...to-the-raf2000

For two years and 125+ hours I've greatly enjoyed my total Sport Copter upgrade (blades/hub bar/rotorhead, mast plates, and 4-way air-trim).
It's not an inexpensive upgrade, but nothing of high-quality ever is.

Safe flying!
Kolibri
 
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Vance

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Kolibri;n1129214 said:


Thus, the stick neither moves forward or back. This seems to be what Sport Copter pilots experience. I do.
The AofA stays (within safety margins) as flat as it can be, and reducing drag and increasing performance in all ranges (takeoff, climb, cruise, glide, and landing).
Also, the stick does not become lighter at higher speed, requiring the lessening of trim along the way.


The price for that? Heavier trim pressure throughout all AS, but that's what trim is for. It's not as if the pilot must hold stick pressure himself.
Once level flight is achieved, trim it out and you can thereafter leave it alone as it will remain pretty constant at all airspeeds.


Safe flying!
Kolibri


In my opinion the first statement is representative a serious misunderstanding of gyroplane aerodynamics.

In The Predator I trim for a specific air speed rather than all air speeds.

I have not flown a gyroplane where I trim for all airspeeds with a single setting.
 

Kolibri

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“Brevity is the soul of wit” –Shakespeare
It takes more words to unravel a misstatement than to make one.
Sport Copter rotors do not exhibit your "
dangerous" characteristic of continual back stick, Chuck.

_____
I have not flown a gyroplane where I trim for all airspeeds with a single setting.
Vance, you don't fly on a Sport Copter rotorhead and blades, which is what I was discussing there.
What your SC blades do on your Predator's non-SC rotorhead is different.

If a negative pitching moment was such that the rotor tip's down twisting generally countered the blowback effect,
then the cyclic flapping angle would remain pretty constant, and the stick would not significantly move with increasing AS.

Regards, Kolibri
 

Vance

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Kolibri;n1129232 said:
Vance,

If a negative pitching moment was such that the rotor tip's down twisting generally countered the blowback effect,
then the cyclic flapping angle would remain pretty constant, and the stick would not significantly move with increasing AS.

Regards, Kolibri
In my opinion this is wrong on many levels and further discussion would be pointless.
 

fara

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Kolibri;n1129232 said:
_____

Vance, you don't fly on a Sport Copter rotorhead and blades, which is what I was discussing there.
What your SC blades do on your Predator's non-SC rotorhead is different.

If a negative pitching moment was such that the rotor tip's down twisting generally countered the blowback effect,
then the cyclic flapping angle would remain pretty constant, and the stick would not significantly move with increasing AS.

Regards, Kolibri
First sentence quoted here is simply the result of SC rotorhead design and I would like to know if you think this is acceptable behavior in a stability test or not? What do you think?
Regardring the second statement ... what? I am lost.
 
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Kolibri

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Perhaps think it through some more?

Regarding the possible range of pitching moments (+, 0, - ) we're discussing a continuum, not either/or behavior.

+x Cmo pitches up and adds to blowback effect
with AS, cyclic flapping angle greatly increases, and stick moves forward to the stop

0 Cmo is neutral in pitch
with AS, cyclic flapping angle moderately increases (due to blowback effect), and stick moves somewhat forward

-x Cmo pitches down and counteracts (to y degree) blowback effect
with AS, cyclic flapping angle (depending on -x and construction of blade) either does not increase or decreases, stick has little movement

What I've postulated all along is a small amount of negative Cmo in a rigid blade is not inherently "dangerous"
because the blowback effect is not completely overwhelmed.

Now, I'm not claiming that the relationship between -Cmo and blowback is 1:1 over all airspeeds, but given the well-known
Sport Copter performance amongst hundreds of machines, their lack of "stick moving back with AS" is clear evidence
that Vanek's -Cmo airfoil enjoys rather a just-enough-but-not-excessively "sweet spot" in countering blowback effect .

I.e., if the SC stick does not routinely shift aft with increasing AS, that means that the cyclic flapping angle is remaining pretty constant.
Thus, there is much less need to re-trim for cruise airspeeds.

In short, at cruise there is a rough equilibrium between blowback effect and negative pitching moment.
While the data curves of each force do not perfectly overlap, there's apparently good overlap in a wide range of cruise AS.

Think "continuum" and it'll make sense.

If Chuck wishes to continue to assert that any -Cmo will at "
some airspeed" cause the gyro to descend beyond cyclic authority of correction,
then he should quote that airspeed. If, as I suspect, it is so high (e.g. 185kts, a multiple of the gyro's Vne, and thus silly), then realistically his accusation is baseless.
If that AS were <Vne, then he'd have an actual point here, but it's a broad brush boogeyman.

As I mentioned, Jim Vanek has tested his airfoil in a dive at 145mph, which was obviously not unrecoverable since no crash ensued.
And, really, can anyone actually imagine that Jim would be selling rotors which were notorious for continual aft stick with airspeed?

I'm aware of zero crashes of any Sport Copter due to deficiencies in materials or design.
How's that for "stability", fara?

Regards, Kolibri
 

fara

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Kolibri;n1129301 said:
Perhaps think it through some more?

Regarding the possible range of pitching moments (+, 0, - ) we're discussing a continuum, not either/or behavior.

+x Cmo pitches up and adds to blowback effect
with AS, cyclic flapping angle greatly increases, and stick moves forward to the stop

0 Cmo is neutral in pitch
with AS, cyclic flapping angle moderately increases (due to blowback effect), and stick moves somewhat forward

-x Cmo pitches down and counteracts (to y degree) blowback effect
with AS, cyclic flapping angle (depending on -x and construction of blade) either does not increase or decreases, stick has little movement

What I've postulated all along is a small amount of negative Cmo in a rigid blade is not inherently "dangerous"
because the blowback effect is not completely overwhelmed.

Now, I'm not claiming that the relationship between -Cmo and blowback is 1:1 over all airspeeds, but given the well-known
Sport Copter performance amongst hundreds of machines, their lack of "stick moving back with AS" is clear evidence
that Vanek's -Cmo airfoil enjoys rather a just-enough-but-not-excessively "sweet spot" in countering blowback effect .

I.e., if the SC stick does not routinely shift aft with increasing AS, that means that the cyclic flapping angle is remaining pretty constant.
Thus, there is much less need to re-trim for cruise airspeeds.

In short, at cruise there is a rough equilibrium between blowback effect and negative pitching moment.
While the data curves of each force do not perfectly overlap, there's apparently good overlap in a wide range of cruise AS.

Think "continuum" and it'll make sense.

If Chuck wishes to continue to assert that any -Cmo will at "
some airspeed" cause the gyro to descend beyond cyclic authority of correction,
then he should quote that airspeed. If, as I suspect, it is so high (e.g. 185kts, a multiple of the gyro's Vne, and thus silly), then realistically his accusation is baseless.
If that AS were <Vne, then he'd have an actual point here, but it's a broad brush boogeyman.

As I mentioned, Jim Vanek has tested his airfoil in a dive at 145mph, which was obviously not unrecoverable since no crash ensued.
And, really, can anyone actually imagine that Jim would be selling rotors which were notorious for continual aft stick with airspeed?

I'm aware of zero crashes of any Sport Copter due to deficiencies in materials or design.
How's that for "stability", fara?

Regards, Kolibri
No. I know what Blowback effect is and I know what negative pitching moment is. Your theory that negative pitching moment of the forward going blade counters the blowback effect keeping flapping angle constant ... constant relative to what, I can only guess to increasing airspeed ... well that is a new one. So we should all design rotor airfoils with negative pitching moments then to increase the VNe of rotorcraft?

First, stability and controllability are two very different things. You should learn the difference between the two. A good pilot will always take controllability over stability and if he does not know enough confuse it for stability. Unfortunately in the US gyroplane community this is specially true from what I have seen.

Zero crashes from deficiencies in materials has no bearing on stability. There are zero crashes from deficiencies in materials in Averso Stella rotors as well. Does that make them stable. Not at all.
Take off all the trim springs and air or electrical linear actuators in your gyroplane and fly it and let me know if it has a neutral point at a reasonable point below Vne. Meaning take your hands off and let it find its neutral without any pitch trim of any kind attached. Do this at idle. Then do it with high cruise power. The gyroplane is allowed to climb or descent but has to find its neutral speed. What is that neutral speed for you? and what is your Vne? In AR-1 with Averso Stella this neutral point is around 55 - 60 knots for example. I could cut out all the pitch trim springs and throw them away and take my hands off and that's where it will be.

Then disturb the cyclic by pushing it forward and releasing it? What does it do initially?
Then if the above returns towards its original position, allow it to continue moving. What is its response and does it settle after X oscillations to within 10% of its airspeed before the disturbance?
How many oscillations did it take to settle?

If initially the cyclic did not return towards its original position. Stop and let me know. No reason to continue further.

Remember all the above is without any pitch trim attached. You can then repeat the same process with a trim and see what results that provides.

Now you have to realize that when we talk about stability we can only consider a whole system, not just rotor system on its own though its possible to come up with an analysis of that. Its only the combined effect of all the elements that makes a whole system stable or unstable. Talking about rotors by themselves is pointless IMHO. Its how they behave with your fuselage, rotor head, empennage , thrust line, drag line, that matters. I like to see a stability even without use of external trim systems. That to me is it but its perfectly acceptable to use devices that trim and use them to achieve the results. The results are what matters. If SC rotors then have to use trim to behave as positively stable between a prescribed speed range to Vne, then so be it. The question is do they show positive stability especially in pitch? and on which gyroplane models?
 
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Vance

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Kolibri;n1129301 said:
Perhaps think it through some more?

Regarding the possible range of pitching moments (+, 0, - ) we're discussing a continuum, not either/or behavior.

+x Cmo pitches up and adds to blowback effect
with AS, cyclic flapping angle greatly increases, and stick moves forward to the stop

0 Cmo is neutral in pitch
with AS, cyclic flapping angle moderately increases (due to blowback effect), and stick moves somewhat forward

-x Cmo pitches down and counteracts (to y degree) blowback effect
with AS, cyclic flapping angle (depending on -x and construction of blade) either does not increase or decreases, stick has little movement

What I've postulated all along is a small amount of negative Cmo in a rigid blade is not inherently "dangerous"
because the blowback effect is not completely overwhelmed.

Now, I'm not claiming that the relationship between -Cmo and blowback is 1:1 over all airspeeds, but given the well-known
Sport Copter performance amongst hundreds of machines, their lack of "stick moving back with AS" is clear evidence
that Vanek's -Cmo airfoil enjoys rather a just-enough-but-not-excessively "sweet spot" in countering blowback effect .

I.e., if the SC stick does not routinely shift aft with increasing AS, that means that the cyclic flapping angle is remaining pretty constant.
Thus, there is much less need to re-trim for cruise airspeeds.

In short, at cruise there is a rough equilibrium between blowback effect and negative pitching moment.
While the data curves of each force do not perfectly overlap, there's apparently good overlap in a wide range of cruise AS.

Think "continuum" and it'll make sense.


Regards, Kolibri

Every gyroplane I have flown is trimmed for a specific airspeed and in my opinion it would be a bad thing if it were not so. Some are in flight adjustable and some are ground adjustable.

I love my Sport Rotors on The Predator and have another set coming because mine are nearing the end of their useful life at 1,650 hours.

I don’t see a reason to attribute unlikely features to Sport Rotors. In my opinion the rotor system is a quality product at a reasonable price.

I feel there is no magic in having a different gimble offset and no reason to attribute the difference to the Sport Copter rotor head.

In my experience more trim spring is required if the gimble offset is not reduced when changing to Sport Rotors.

I have not found an airspeed where my Sport Rotors behave badly.
 

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AR-1
Total Flight Time
3600+ .. New to gyroplanes
Vance;n1129318 said:
Every gyroplane I have flown is trimmed for a specific airspeed and in my opinion it would be a bad thing if it were not so. Some are in flight adjustable and some are ground adjustable.
Hi Vance:
May be I am not clearly understanding this but if you look at trim systems of various gyroplanes like Magni, AutoGyro, ELA etc. they trim airspeed by pulling down of the aft side of the rotorhead. Basically slowing the aircraft down. If that trim was not there the gyro would want to gain speed and dive to some degree. That degree is way past 60 knots. Probably close to Vne or even past it. I don't exactly know. I only know that the airspeed trimming mechanism is only pulling back on the head. If the trim stops working it takes a lot of effort to hold the cyclic in a normal speed range for the pattern.
That is not the case for us at least. I am not 100% sure why that is. Is it the rotor system from Averso but Apollo AG-1 was the same way as AutoGyro and it used Averso rotor blades so I doubt it. I do know that unlike Apollo or AutoGyro, ELA and Magni etc. AR-1 has its thrust line within 2 inches of its vertical CG in a double hang (pivot) test and may be its the lack of the moment from thrust that makes this happen. Never really thought this through. We just tried to make it close to center line thrust when working on AR-1 and making changes. AR-1 would pitch up if you put power in abruptly and did not hold the cyclic pressure, not down. The HS incidence angle is reduced on it because it does not need it as much as Apollo or many of this configuration renditions to provide adequate balancing force because of reduced moment from thrust
 
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Vance

Gyroplane CFI
Joined
Oct 30, 2003
Messages
16,081
Location
Nipomo,California
Aircraft
Givens Predator
Total Flight Time
2400+ in rotorcraft
Kolibri;n1129214 said:
Thus, the stick neither moves forward or back. This seems to be what Sport Copter pilots experience. I do.
The AofA stays (within safety margins) as flat as it can be, and reducing drag and increasing performance in all ranges (takeoff, climb, cruise, glide, and landing).
Also, the stick does not become lighter at higher speed, requiring the lessening of trim along the way.


The price for that? Heavier trim pressure throughout all AS, but that's what trim is for. It's not as if the pilot must hold stick pressure himself.
Once level flight is achieved, trim it out and you can thereafter leave it alone as it will remain pretty constant at all airspeeds.


Safe flying!
Kolibri[/COLOR]
I find hKolibri’s posts confusing Abid; so perhaps I have not been clear.

I find for most clients having the aircraft trimmed for a specific airspeed helps them to meet the plus or minus five knot on descent to land practical test standard.

Kolibri appears to me to be writing that if a rotor blade has the correct pitching moment that it will be trimmed for all airspeeds.

I have not flown a gyroplane that was trimmed for all airspeeds and in my opinion that would negate the concept and value of trim.

I love it that the American Ranger doesn’t have power/pitch yaw coupling.

All of the gyroplanes I have flown had power/pitch yaw coupling with the exception of The Predator and the American Ranger.

The power/pitch/yaw coupling talk is a large part of transitioning my clients into the gyrolane used for their proficiency check ride.


Power/pitch/yaw coupling is not what I was writing about, only the value of trim.
 
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