Negative Gs?

fara

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A reduction of “G” load that does not result in a tumble requires essentially no altitude for recovery.

Duck, dodge and obfuscate
Lets do the test then. Should be no problem. Why "duck" it. Lets do a zoom climb from S&L Vh starting at 2000 feet to 2500 feet (or where the speed decays down), shove the stick all the way forward on Aviomania to get low G's with unloaded rotors like in the accident and recover with no loss of altitude or very little loss of altitude (say 50 feet or less), all the while at full power setting. Easy. Record it and do it with the composite body version with a G meter and a few Go Pros, one focused on the G meter, one on the cyclic to show he shoved it forward all the way after a zoom climb and one on a sensitive altimeter. If you want a test script written, I'll write it and give it to you or anyone willing to do it. Game on? I suggest the test pilot buy a parachute and learn to bail out first.
Another view from outside from another aircraft looking at this aircraft would be very valuable as well.
 
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C. Beaty

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It’s up to the people selling a product to prove its safety.

When Nick Karaolides says that he’s pushed his Aviomaqnia gyro over to terminate of a zoom climb and has seen zero “G”, I believe him.
 

fara

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It’s up to the people selling a product to prove its safety.

When Nick Karaolides says that he’s pushed his Aviomaqnia gyro over to terminate of a zoom climb and has seen zero “G”, I believe him.
Good for you. Now for the rest of us, lets follow a script I write which will be close to what happened in the WAG accident and see how it will cope. That is what your (not Nick's) claim is. He has to do the same pilot actions and same attitudes that the pilot in WAG accident did. There is a video of that accident so we can safely come up with that sequence or close.
 

C. Beaty

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I also believe Cierva knew what he was doing when he arranged the propeller thrust line to pass through the CG and used differential tailplane incidence to balance propeller torque.
 

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C. Beaty

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Cierva's torque compensation patent (US2098230 A):

The problem of correcting the airscrew reaction torque presents no serious difliculty in ordinary fixed Wing aeroplanes. On account of the great span of the fixed wings the motion of an aeroplane is heavily damped in roll and in addition the lateral stability is generally such that large restoring forces in roll are produced. For this reason the rolling moments applicable by the ailerons are of a fairly large order when compared with theY torque reaction so that no special means of correcting thelatter are in general required. 0n the' other hand, in rotarywinged aircraft in which the lateral control is effected by operating on the rotor itself, the damping in roll is of a very small order, more especially when the rotor is of the kind having hinged blades as aforesaid. At the same time, although such an aircraft may be made laterally stable, as for instance by means of the stabilizing devices described in my aforementioned application No. 645,985, the degree of stability is in general such that the restoring -forces are of a small order.

The problem of torque reaction correction therefore assumes great importance. In fact, it has been found (in machines employing tilting of the lrotor forcontrol purposes) that a greater amplitude of lateral control movement of the rotor is required'to compensate the torque reaction 'in all conditions of flight from engineoff to full throttle kthan is required for the purpose of lateral control. Further, if the torque reaction is compensated by displacement of the rotor, or by an equivalent (such as modification of the periodic pitch variations of the blades thereof) a continual adjustment is necessary during ilight, since, while at a constant throttle setting the reaction torque is substantially invariable, the couple opposing it is the resultant of aerodynamic forces (for which the rotor is principally responsible), inertia forces and gravity; the aerodynamic f orces being subject to fluctuations on account of wind gusts and changes -of attitude of the aircraft while the inertia forces vary with the accelerations to which the According to the present invention, in a rotative-winged aircraft of the type herein referred to, wherein the lateral control, i. e., control in roll, is effected byoperating on the rotor either by tilting it bodily or by controlling the pitch angles of the rotor blades to produce a lateral tilting of the path swept by the tips of the rotor blades, aerodynamic means such as one or more fixed aerofoil surfaces are provided, situated within the slipstream of the airscrew or airscrews, and so disposed angularly to said slipstream or streams that the effective angle of incidence to the slipstream of the whole or part' of such surface on one side of (or above) the longitudinal axis of symmetry of the aircraft differs from that on the other side of (or below) said axis of symmetry, so that an aerodynamic couple is produced neutralizing the airscrew reaction torque. Stated in another way, one or more such surfaces is placed at such an angle to the longitudinal axis of the slipstream as to produce a couple substantially neutralizing the airscrew reaction torque on the aircraft.

The compensating couple vproduced in this manner is substantially self-regulating, in that it varies substantially in accordance with the reaction torque. The velocity of the slipstream, and hence the compensating couple, is largely independent of the speed of flight'. As the speed of iiight is increased the velocity of the slipstream does in fact increase slightly but I have found that the eifect ofthis is more or less balanced automatically by a simultaneous reduction in the an'gle of swirl or twist of the slipstream. Variationof the reaction torque by altering the throttle setting of the engine is automatically compensated by a corresponding variation in the slipstream velocity.

The present invention may be carried into practice in a single engined or tandem engined aircraft preferably by providing a pair of fixed fins or surfaces disposed symmetrically with respect to the axis of the slipstream and set with-a differential angle of incidence with respect to one another, the difference in the angle of incidence of the respective surfaces being arranged with respecty to the direction of rotation of the slipstream so as to produce. a couple` opposing the reaction torque. A

It will in some cases be sufficient to employ surfaces witlra fixed differential angle of in' cidence but in order to obtain greater accuracy in correcting the reaction torque in all conditions offlight the differential angle of incidence may be made adjustable under the control of the --pilot either by movablyv mounting one or both of the surfaces as a whole or by the provision of movable trailing naps.

The fins or surfaces for correcting the reaction torque may be arranged either vertically or horizontally or in any other suitable way, and in` order to simplify the construction of the aircraft and to effect the greatest possible economy in weight and parasite drag the xed ns or surfaces for correcting the reaction torque may be combined or made identical with fins or surfaces provided for other purposes. For instance, theyimay consist of a pair of small horizontal xed wings near the front of the aircraft which are incorporated in the structural arrangements of the aircraft either as part of a 4 angles of incidence.

wheel under-carriage or for supporting lateral floats or the like. Alternatively they may consist of more or less vertical surfaces forming fairings around members of the under-carriage below the body and/ or around a member or members constituting the rotor supporting structure above the body. Again, vertical tail fins disposed above and below the body may be given a differential incidence setting for the purposes of the present invention.

` Preferably, however, the fixed surfaces [or correcting the reaction torque according to the presentinvention are combined with horizontal surfaces forming a stabilizing tail. The dierential incidence setting may be achieved in any convenient way. It is only requisite that the nolift lines of the aerofoil sections of the two members constituting a pair of surfaces as provided for the purpose of the present invention, should be arranged at angles of incidence differing by an amount suilcient to provide the required reaction torque correction. If the two. surfaces of any pair have the same aerofoil section they may be set throughout with diierent Alternatively the same result may be achieved by means of wash-in and wash-out. Again the true angles of incidence oi the 'respective members of a pair may be made to differ without relative displacement of the structural elements (such as spars etc.) on which 'the surfaces are built by using for one of the members of the pair an aerofoil section differing from that of the other member 0r (if the aerofoil section is `unsynimetrical) the same aerofoil section reversed.

For the purpose of the present invention more than one pair of reaction torque correcting surfaces may be employed if desired.

A further object of the present invention comprises the eliminatinor compensation of effects of yawing produced by the slipstream.- This is of particular importancein the case of aircraft of 645,985 and necessitates the employment of a more or less vertical fin surface at the tail of the I aircraft.' v y v If a vertical nsurface is placed unsymmetrically with respect to the slipstream, that is with its aerodynamic center of pressure either above' or below the axis of the slipstream (more generally above), the swir of the slipstream exerts an unbalanced side force on such a fin which tends to make-.the aircraft yaw. `If this eifect is corrected by angularly offsetting the nn a. side force tending to yaw the aircraft in the opposite direction is produced when the engine is throttled down. In ordinary aircraft having a rudder or rudders for directional steering this effect would be of minor importanceas the yawing tendency in either direction could be easily oorrectedby means of the rudders but it becomes a unique problem in aircraft'in which the rudder is dispensed with as above described.

According to a feature of the present invention therefore, vertical fin surfaces arranged or mounted at the tail of the aircraft for directional stability purposes are arranged to beaerodynamically symmetrical with respect to the slipstream.
 

fara

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I also believe Cierva knew what he was doing when he arranged the propeller thrust line to pass through the CG and used differential tailplane incidence to balance propeller torque.
Cierva seems to have angled the engine to pass the thrustline through CG. That does not require hanging the prop hub to be exactly in line with CG. I can do that (and already have that to a certain extent) in our gyroplane angling the engine but going further that creates other issues like increasing p-factor that enhances rolling tendency.
 

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The study is flawed if you measure the vertical CG as you are measuring it. So this 2 inches thing is right out the window.
Abid, for me, as a casual reader of this thread, if your argument hinges on some alternate means of measuring CoM that calls early Magnis CLT, the game is over. There is no such thing as a center of mass "for stability purposes" which differs from a CoM for any other purposes. The term has an accepted scientific meaning, and a dual hang test can find its vertical coordinate on an airframe.

There have been several attempts over the years to redefine "centerline thrust" to claim this or that machine was CLT. RAF reps insisted CLT required aiming thrust through the center of pressure, not CoM. Jim Fields told us in a webinar that the HoneyBee G2 is centerline thrust as defined by Ralph Taggart, whatever that means. The designer of one popular low-rider design recently told us center of mass and center of gravity are not in the same place during certain maneuvers.

You're responding to relatively simple questions with long, defensive posts. I think Greg Gremminger demonstrated years ago you can't win an argument by burying us in word count. If 90% of your audience glasses over before they get to the end of your posts, you can't assume they come away thinking you're right. That approach looks too much like obfuscation to be credible.

I don't really have a dog in this fight. I'm not interested in a two-seat gyro. So my opinion may not matter, but I believe the laws of physics apply without qualification to gyroplanes. I like to see kitmakers explain in scientific terms how they approach managing torque forces, not dismiss them as irrelevant or unavoidable.

Attempting to demean the products of another company which is trying to manage these forces better makes YOU the one who needs to come up with data to prove your point, not Nicholas. Define the safe envelope for your own product, let him do the same with his. If he's lying, we'll know soon enough.
 

C. Beaty

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Bensen angled the engine 10º propeller end up to align engine thrust line with CG on the B-8.

His vector diagrams always showed both propeller and rotor thrust lines passing through the CG and his example weight and balance sheet for certification specified CG location as being on the propeller thrust line.

In practice, only with seat tank and light wheels was the B-8 CLT.

Bensen ignored propeller torque compensation, perhaps because it didn’t amount to much with a Mac engine spinning the prop at 4,000 rpm but it was nonetheless a problem.

Most of the people scaling up Bensens were amateur “designers” without much comprehension of such things.
 

fara

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Chuck:
Cierva's patent for trying to compensate torque roll

1) Has many options and nothing like your one prescriptive advice that you have boxed yourself in and continue to insist is "the" way.
If you are going to use "appeal to authority" fallacy to make your argument its illogical to use this because it proves my point that you are way too prescriptive and in fact fixed differential angle of incidence in absence of engine torque, low RPM, produces its own moments as the air speed increases. He left the door open to use pilot controlled elevator trim tab like device or pilot controlled incidence angle of HS halves or vertical airfoils or wheel pants or differential washout or offset halves and some others as stated in the patent very clearly. He is no where near boxed in like you.

So what happens when your solution of fixed differential Horizontal Stab incidence is used and the pilot is flying at 90 mph and goes to idle to glide and then hits your proverbial lee side mountain downdraft or he just shoves the stick forward? The differential anti torque action is still there experiencing 90 mph relative wind, except it has no torque to balance now so what now? Your solution creates another problem when engine is at idle, rest of scenario being the same. Now there is tendency to roll constantly the other way. You are back to square one without the engine power at high setting.

2) Cierva's patents were in the 1920's and 30's. The dampening of roll in airplanes is only dependant on airplane design. If I break the net dihedral effect and reduce roll yaw coupling and create a net anhedral effect in a fixed wing, the dampening is much less, actually can even be negative. Something Cierva has not mentioned here

3) Cierva is also assuming that airplanes do not do anything to counter engine torque because its a non event there. That is just false today. It may have been true with low powered aircraft of 1920's and 30's. It certainly isn't true today. They have this problem and they do do things to counter it.

4) Rudder and rudder trim tabs are present in gyroplanes today so the last point is moot. I can offset the vertical stab slightly to one side, angle the rudder, bend the rudder tab or a combination of these to deal with spiral slipstream

Anyway, I hope you are having a great holiday. I have only been able to write all this here because of this holiday time though I may be getting close to a divorce call now. My employees refused to work this Friday and Saturday. Slackers.

In the end I will say just this.
Till you have testable criteria and have conducted tests to show your theories actually work in the extreme circumstances, you or Aviomania or Dominator have no business trying to promote that they are holier than thou in their products.
I also have to state doing some of this testing is inviting danger to pass you very closely and I in no way am trying to appeal to someone's mahcismo to go and do these tests. I wish for all of us to remain safe.
There are limitations to each type of aircraft and we need to learn that aircraft that by nature are not made to handle negative G that are sustained, should not be put there by the pilots by shoving the stick forward like in an airplane at stall. No one should ever do that in a gyroplane. You are an "experiment" when you take yourself there regardless of what brand or design gyroplane you are flying.
 
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fara

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Bensen angled the engine 10º propeller end up to align engine thrust line with CG on the B-8.

His vector diagrams always showed both propeller and rotor thrust lines passing through the CG and his example weight and balance sheet for certification specified CG location as being on the propeller thrust line.

In practice, only with seat tank and light wheels was the B-8 CLT.

Bensen ignored propeller torque compensation, perhaps because it didn’t amount to much with a Mac engine spinning the prop at 4,000 rpm but it was nonetheless a problem.

Most of the people scaling up Bensens were amateur “designers” without much comprehension of such things.
Yet even in original configuration there were many fatal accidents in the Bensen B-8. No horizontal stab, chordwise flexible rotor
 

fara

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Abid, for me, as a casual reader of this thread, if your argument hinges on some alternate means of measuring CoM that calls early Magnis CLT, the game is over. There is no such thing as a center of mass "for stability purposes" which differs from a CoM for any other purposes. The term has an accepted scientific meaning, and a dual hang test can find its vertical coordinate on an airframe.

There have been several attempts over the years to redefine "centerline thrust" to claim this or that machine was CLT. RAF reps insisted CLT required aiming thrust through the center of pressure, not CoM. Jim Fields told us in a webinar that the HoneyBee G2 is centerline thrust as defined by Ralph Taggart, whatever that means. The designer of one popular low-rider design recently told us center of mass and center of gravity are not in the same place during certain maneuvers.

You're responding to relatively simple questions with long, defensive posts. I think Greg Gremminger demonstrated years ago you can't win an argument by burying us in word count. If 90% of your audience glasses over before they get to the end of your posts, you can't assume they come away thinking you're right. That approach looks too much like obfuscation to be credible.

I don't really have a dog in this fight. I'm not interested in a two-seat gyro. So my opinion may not matter, but I believe the laws of physics apply without qualification to gyroplanes. I like to see kitmakers explain in scientific terms how they approach managing torque forces, not dismiss them as irrelevant or unavoidable.

Attempting to demean the products of another company which is trying to manage these forces better makes YOU the one who needs to come up with data to prove your point, not Nicholas. Define the safe envelope for your own product, let him do the same with his. If he's lying, we'll know soon enough.
What.
No not me that was University of Glasgow study that all CLT supporters use as gospel to point to. That gospel is flawed.

I am not claiming CLT nor do I proclaim that CLT solves the stability problem except in one minute area. CLT to me is better for efficiency.

I am NOT THE ONE demeaning the product of another company. Chuck, Birdy, many others who continue to demean products of Magni, AutoGyro Gmbh, ELA etc. They continue to do it unchecked for all the years I have been here. They talk about very prescriptive solutions that help the ego of someone. Nothing I have written is demeaning anyone's product. I have stated that you can't claim something based on your ideas till you have proof of testing showing it and you can't demean someone's products till you have testable criteria that someone can test against to show whether they comply or not. Just because they don't use "someone's" exact solution, does not mean they can't meet a safety criteria. No safety criteria that is testable has been put forth. That would be step number 1.

You can't claim superiority when you can't come up with this criteria, develop a testing protocol against it and show proof that you executed the testing protocol and came out meeting the criteria successfully.

Here is the SUMMARY for you:

1) Chuck's ego is not my problem
2) Aviomania cannot say they are safer till they show by testing why. I do not drink the koolaid
3) By saying without proof they are safer to the point of a matter of life and death, in fact is the demanding of other's products indirectly. I didn't pay much attention to Aviomania till Nick came in the WAG accident thread and posted some pretty far out claims IMHO.
4) Theories are theories till they are proven by tests
5) There are other ways of gaining stability not just Chuck's prescriptions
6) Stop using Univ of Glasgow study to support CLT as it has been shown to be flawed
7) CLT helps in stability in one set of variables and that's it.
8) LTL relies on power to provide loading which is also a quarter baked solution because it assumes power is at high setting by the pilot when low G happens
9) Differential incidence Horizontal Stab (HS) halves that are fixed create rolling moment of their own at any significant speed and at engine idle. And gyroplanes do go to idle and fly at some speed and there has been no law of nature saying that a very low G event can't happen when gyroplane is at idle in the sky


Hope this is what you take from this.
 
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fara

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Birdy, don’t you know that pocketbook issues trump morality?
Another personal dig.
You just can't gain respect from someone like me this way Chuck. You need to act much more mature and serious than this.
Very disappointing.
 

fara

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Good for you. Now for the rest of us, lets follow a script I write which will be close to what happened in the WAG accident and see how it will cope. That is what your (not Nick's) claim is. He has to do the same pilot actions and same attitudes that the pilot in WAG accident did. There is a video of that accident so we can safely come up with that sequence or close.

This offer is still on Chuck. Arrange it. I will write the whole test script. You just stopped and changed the subject after this but I am serious. This is one way to prove your prescriptions right. Nick in my estimation has never claimed his machine could recover from unloaded rotors in very little altitude loss but you have. Lets put it to the test.
 

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Abid,

I have lurked at this thread occasionally. I see a lot of words, but very little content from you regarding the theory, facts, calculations put forward.

There is no safe way to go over the boarder of PPO or torque over, so the proof, where the boarder is, would be paid with fatality. However there are simple rules which stand, without proof:

- if you eliminate torque completely, i.e. if adding or removing thrust does not make the airframe wriggle, then you don't have torque over to fear. The only way to achieve this is to aerodynamically un-twist the prop-wash with an appendage of the airframe, where the prop is mounted.
- if you, however, like MTOs, reduce torque with a short rudder and an offset roll-hinge, then it is still there and may bite you in an adverse condition. I avoid slipping now in AGE products.
- Yes theories must be proven. In the light of the usually fatal outcome, it may pay to look at the number of accidents attributed to torque roll and the aircraft types associated and deduct from it.
- can you state a situation where HTL is helpful?
- The differential of the HS only has to be very small, as the prop-wash is way faster than the airspeed you may reach at idle. So the adverse effect of it in idle is negible.
- Tandem Euro-tubs have good longitudinal stability, simple because of the large HS way out there. That is a given. However, the same is not true for roll stability.

Kai.
 
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C. Beaty

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Abid, you’re using every trick you can muster to prove, beginning with Cierva, that those who believe the ox should be hitched to the front of the cart are wrong.

I believe that such obfuscation is for the sole purpose of protecting the investment you’ve made in a Magni clone.

Rather than asking others to prove their designs, why don’t you prove your own clone?

I have never had any interest in manufacturing gyros, have never sold a gyro, have never owned a Dominator nor any other commercial design.

My first gyro was built from Bensen plans but used 2½ inch round 2024 aluminum tubing with Hughes 269 helicopter rotor blades and incorporated a large horizontal stabilizer. Bensen said it was not a Bensen even though I had registered it as a Bensen.
 

C. Beaty

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The early Pitcairn AC-35 initially tried contra-rotation of propellers to eliminate torque roll but was abandoned because it was too noisy, heavy and expensive.

The next attempt was with the catwhisker vanes, designed by NACA engineers and mounted directly behind the prop. Ugly, ungainly and awkward.

The final solution was by differential horizontal tailplanes, centered in the propeller slipstream.
 

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Murray Barker

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Fara you have not read what I am saying.

I said "As would a Magni if it had a Subaru with the redrive down" I know Magni dont make gyros with Subaru engine. its just a way of trying to tell you a Magni with anyother engine i.e. an Arrow engine in the Glasgow report can have a totally differant COG/Thrustline.

It is in no way indicitive of todays Magni's.

And yes I have read the report.
 
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Brent Drake

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Yet even in original configuration there were many fata
l accidents in the Bensen B-8. No horizontal stab, chordwise flexible rotor
Ive always thought the rock guard on a Bensen was a horizontal stab.
 
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