VNE Question

StanFoster

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Chuck: I haue rread from RAF a VNE of 100 mph- until you have 100 hours experience. After that I dont know. Stan
 

scottessex

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According to thier website..........


Performance Chart
RAF 2000 GTX SE RAF 2000 GTX SE FI RAF 2000 GTX SE FI 2.5
Minimum Speed 10-12 MPH 10-12 MPH 10-12 MPH
Cruise Speed 70-80 MPH 70-80 MPH 90 MPH
Maximum Speed 120 MPH 120 MPH 140 MPH
Recommended VNE
(Until 250 Hrs Accrued) 100 MPH 100 MPH 100 MPH
Stall Speed N/A N/A N/A
Landing Roll 0-10 ft. 0-10 ft. 0-10 ft.
Rate of Climb 1200 FPM 1200 FPM 1500-2000 FPM
Performance figures are not based on theoretical maximums. All data is based on accurate, in-flight measurements.
 

Steve Osborne

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I believe around 1993 there was a speed restriction of 70 mph if your kit did not have the lexan reinforcement strap installed.

It is up to the builder to set the VNE on there aircraft, so I would say that RAF has made a suggest VNE as Scott posted above.
 

Chuck_Ellsworth

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What would be the VNE imposed for, what factor would the VNE be put in place for?

Any idea what angle the relative wind to the rotor would be at140 MPH in an RAF?
 

dragonflyerthom

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Chuck E

You would know more about this than we would. You are the former RAF certified Rep.and instructor aren't you? What are you trying to get at?
 

mcbirdman

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Oh - now the "Devil"..... an experienced life time pilot with more ratings than anyone else on this forum wants to make a point and he becomes the devil....

Things are getting even more desperate.... Anticipating the answers again I see.

Let's see, technical discussion not going the way you feel it should, history showing serious problems and general lack of interest in becoming the next RAF pilot. What is there like 3 people out there defending a company that won't just make the changes? I bet they love you guys. They can feed you what you want to hear and you can be their latest cheerleaders. They don't have to answer to anything, change anything but have you guys making it seem like we just don't understand. The downside is that we do and every time we lose another friend the fun does'nt seem to matter as much and the gyro community as a whole suffers a little more as bragging rights to gyros being the safest form of flight phrase becomes more and more dated.

It was the safest form of flight in the begining and look where these designs we are arguing about have us now... The phrase wouldn't seem so contridictory to repeat if we weren't still flying unstable machines that are robbing us from this once proven statement. Look where we are. Look at what we know and compare it to what we do.
What machines do you think have been damaging? Have the flaws been fixed or simply minimized as a minor problem?

Amazing that people really expect us to be taken seriously while tinkering with bandaid type fixes applied for how many years and for such seriously flawed machines with so many shortcomings. Amazing that something so futuristic is being outperformed by the original design. Are you guys sure you aren't just flying a time machine? I know that it makes me want at least - to go back in time when gyros were the safest form of flight. These new ones have only borrowed and lived off the safety record of the original autogyros for far too long and have in fact left a lot to be desired. It will stay that way until major changes are made and all the arguing in the world will not make it so or what you wish it was. If the aircraft will NOT pass the stability test what does it make it? You are the ones investing your life in it - the history, concerns, equations and conclusions, and characteristics are weel documented so any more is just a WOT. Not only far from safe in regards to GA but much farther from the safety expectations /baseline established back in the 20's with autogyros. That is not what I call progress. It is clearly a deficit/blackmark that we all bear. It is much more than just arguing about preferences. In aviation if Gyros are anamolous to safety and we are interested in gyros because of safety then tell me why it isn't so? jtm
 
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Chuck_Ellsworth

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" You would know more about this than we would. You are the former RAF certified Rep.and instructor aren't you? What are you trying to get at? "

Thom, you have misunderstood my relationship with RAF.

I was never a RAF reprsentative nor was I ever a gyroplane flight instructor.

I did own a flight school with both fixed wing and helicopter instruction and was interested in adding gyroplanes to my school in 1991/92.

RAF was a Canadian company and I bought an RAF 2000 with the agreement that my school would set up the training program under my Transport Canada flight school operating certificate.

My association with RAF lasted less than six months.

I do not even hold a Canadian gyroplane pilot license.

What I am trying to " get at " as you put it is quite simple.

I am trying to find out how the VNE is arrived at and by who doing what flight tests and using what criteria to arrive at the VNE.

Having never been in an RAF 2000 flying at 120 MPH much less 140 MPH and I am curious as to how it behaves and how safe it would be at that speed should it encounter marginal or very rough turbulence.

So my question was asked to see if a intelligent and thoughtful discussion could be generated so as to better understand the aerodynamics and physics acting on an RAF 2000 at those speeds.

Chuck E.
 
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Steve Osborne

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My association with RAF lasted less than six months.

I do not even hold a Canadian gyroplane pilot license.

What I am trying to " get at " as you put it is quite simple.

I am trying to find out how the VNE is arrived at and by who doing what flight tests and using what criteria to arrive at the VNE.

Having never been in an RAF 2000 flying at 120 MPH much less 140 MPH and I am curious as to how it behaves and how safe it would be at that speed should it encounter marginal or very rough turbulence.
Chuck E.

I see the Devil has an advocate.

Chuck E, Why don't you ask RAF?

Exactly how much time have you spent in a RAF? about 4 hrs right ? Or was it 4 times around in the pattern?

Gees, I thought I would have at lest one day off from guarding the gates of HELL
 
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RAF 2000 VNE (or for that matter, any VNE)

RAF 2000 VNE (or for that matter, any VNE)

I read the other day in the RAF website that the VNE is 140 MPH. However, the Max cruise speed is 90. This huge difference is somewhat astonishing to me. But then, I am not an engineer. Suffice to say" DO NOT TRY THIS AT HOME"! Retreating blade stall is the most un-fun experience, next to chucking a blade.
Cheers,
Joe Hessberger
 

dragonflyerthom

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Quote Scottessex
Performance figures are not based on theoretical maximums. All data is based on accurate, in-flight measurements.
__________________Quote//

I know I wouldn't like to have been in the RAF 2000 that established the 140 MPH. Vne.

McB

You made a very good and long post but you are so far off base when it comes to me and most other RAF pilot. It is as you put it one time living on different planets. You like the old style and you can have it. I prefer the pusher type. My RAFs rotor system is just as stable as yours. The drag of your ship is about the same as mine. And If my gyro was the tractor type we probably wouldn't even have this discussion. What I would like to know is why do you continue to drag up this discussion. This dog has been whipped way too many times. It is like having the same argument with the wife over and over again. You have your ideas and I have mine. I personnaly will never own or care to own a Tractor type. There is no right because we are soo far apart we will never get togeather. If you want to know why the safty record of the gyro is blemished then you will need to ask someone who knows. 209 I believe is the number of fatal accidents over the years. Really not a bad record for the number of hours flown and the number of gyros that are in service.
The fact that we use auto engines in our experimental aircraft could contribute to this record but I doubt it. The fact that there are still too many people trying to fly gyros without training maybe.:twitch:
The fact that a lot of the pilots love to use their gyros like a roller coaster could be a factor. I believe that Greg G has asked us to not do the zoom maneuver. It is an advanced maneuver and very unstable in any gyro wheather it is HTL NCLT CLT OR LTL. It can cause even most stable gyros to become G load unstable by putting the RTV far enough in front of the VCG that the gyro can tuck it's nose and go on over.


You act like I (as a RAF owner) am in constant contact with the company. Heck I haven't talked with the company nor do I need to since about September. The last time I ordered some parts to complete my gyro. The company really doesn't need me to be a spokesperson for them. If they really thought they needed to come on here and defend themselves they probably would. Some of you have set yourselves up as judge and jury so to speak. You talk about the physics and engineering like you really know where of you speak. Once again I can tell you of the boo boos you as engineers have made. Sometimes you do get it right but other times and they are many you get it wrong. Fortunately for most of us we can fly in the experimental class and experiment on our gyros. This is good. I would imagine if it were all perfect we would all have to fly certified gyros and the experimental class would go away. If certification was or is the answer then the deaths would go away?????? Get real guys it wouldn't because you can't certify stupidity altho you can certify insanity.
I don't know about you but I fly an experimental aircraft. That makes me a test pilot. I will continue to fly mine and make adjustments until I get my RAF to where I want it or crash it or die of old age. Anyway McB is your gyro certified or experimental???:tape:

Chuck E

Sorry for the hyjack.:yo:
 
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C. Beaty

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From Peter W. Brooks, Cierva Autogiros:

“…This was the first Autogiro fatality. Up to this time, more than 120 Autogiros had been built (including more than 30 prototypes), 30 to 40 pilots had been trained on them, and well over 100 pilots had flown Autogiros in the United States alone. About 35,000 hours had been flown over a total distance of about 2½ million miles. This represented a remarkable safety record. For comparison, General Aviation in the United States had an accident rate of about one fatal accident every 5,000 hours in 1939. This had improved to about one every 40,000 hours by 1969-a rate not attained by General Aviation in the United Kingdom until 1974. Autogiros were therefore remarkably safe during this early period, even while engaged in experimental and development flying, their safety record being comparable to General Aviation 40 years later.”

The difference between then and now? Competency of designers; professionals vs. shade tree mechanics.

Attachment: Pitcairn XO-61 pusher of 1941.
 

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Chuck_Ellsworth

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It is simply amazing the responses one gets from the RAF group when you ask a question about the flight characteristics or limits on the RAF 2000.

What possible connection can there be between my flying experience in an RAF and the answer to some questions regarding VNE of the RAF 2000?

If I knew the answer I would not have asked.
 

scottessex

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Are you thinking that the downforce generated by the cabin at those speeds would be unacceptable?
 

Harry_S.

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It is simply amazing the responses one gets from the RAF group when you ask a question about the flight characteristics or limits on the RAF 2000.

What possible connection can there be between my flying experience in an RAF and the answer to some questions regarding VNE of the RAF 2000?

If I knew the answer I would not have asked.



Chuck, I'd like to ask a simple question relative to your inquiry on this thread.

Of all the aircraft...fixed wing and helos you have flown in your...I think 54 yrs. you stated...what was the purpose/reason the VNE/Red Line was imposed on those aircraft...and what qualified that restriction?

Or, did you just accept the Manufacturer's designated VNE, without question?!


.
 

Chuck_Ellsworth

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" scottessex :

Are you thinking that the downforce generated by the cabin at those speeds would be unacceptable? "


That would be one concern Scott, among other things.

My reason for asking is to find out how these numbers were arrived at 120 MPH seems to be getting a little twitchy in a stock RAF, 140 MPH to me sounds down right scarey.

Certified aircraft have a VNE imposed on them through very in depth flight testing and crunching of numbers, and there is FAA approved documentation avaliable for those who would like to read same.

My concern is over eager new commers to gyro flying buying an RAF 2000 and believing that these numbers were arrived at by accepted flight test criteria by pilots trained in the science of flight testing.

Once again I have grave reservations as to the the life expectancy of anyone who thinks an RAF 2000 can be flown at 140 MPH.
 

Doug Riley

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DragonflyerThom, allow me to be a busybody for a sec.'

Your posts indicate that you have learned some good-sized chunks of the theory of gyro stability. That already puts you ahead of a lot of bug-stained oldtimers, who don't understand any of it... and who think that booklarnin' is for pantywaists.

But, but, but... there are some gaps. I suggest you study up some more to make sure you can put it all together.

A gyro can be designed so that it does not become pitch-unstable at any speed. In fact, it should be designed that way. If the rotor thrust line gets ahead of the CM at a given airspeed, then the airframe layout is out of whack. The rotor thrust line should swing farther and farther BEHIND the CM as you go faster, because the rotor flies at a flatter and flatter angle. Meanwhile, with proper positioning, design and incidence, the HS will generate more and more nose-up moment as the gyro goes faster. The nose-DOWN moment created by the flat rotor position and the nose-UP moment created by the HS should continue to oppose each other to preserve a nose-level flight stance.

The rotor thrust line may end up on the wrong side of the CM if the gyro has a cabin that creates a nose-down moment too great for the HS to handle. It may also end up there if the gyro has a HTL that the HS can't handle by itself. In either case, the gyro will fly more and more nose-low as the gyro goes faster and faster, and the machine will feel more "twitchy." A machine that remains pitch-stable as it goes faster will feel stiffer and stiffer as you go faster, not twitchier.

VNE in a stable gyro can sometimes be a function of windshields starting to cave in, running out of forward stick (because the flapping angle gets greater as you go faster) or an unacceptable amount of nose-up or left-banking tendency caused by stalling a large amount of the retreating blade.
 
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