How strong is the M20 wing?

[Shadrach]

Im assuming it's all based on the data they had to work with at the time. It's likely that as new data came to light, subsequent years got higher numbers. Previous years likely remained at the original numbers because of the amount of FAA BS required to update.

[MyNameIsNobody]

I think it was because Kromer whined about not liking that he flies vintage Mooney's in the yellow arc all the time. They were just being environmentally kind and not wasting paint on 1960's airframes...

Edited September 4, 2015 by MyNameIsNobody

[mpg]

I will take your statement and raise it. Why does a 1970 C Model have a bottom of yellow at 170MPH and a VNE of 200 vs. my 1966 M20E? B.S. My "official" yellow bottom is 150 and not 170 and VNE is 189 NOT 200...NO Difference in the airframes like the E and F. I fly it like it was made in 1970...

When did Mooney begin installing "true" air speed indicators,

the type that have a knob to dial in OAT above pressure altitude?

[KSMooniac]

When did Mooney begin installing "true" air speed indicators,

the type that have a knob to dial in OAT above pressure altitude?

 

I believe they were optional, but I'm not sure of the time frames.  I can't remember definitively, but I *think* the '75 F that I flew in the 90's (my transition plane) had one.  My '77 J does not.  My '81 J salvage did have one, and I think I'm going to install it this weekend since I'm monkeying with the pitot-static system anyway.

[Marauder]

I believe they were optional, but I'm not sure of the time frames. I can't remember definitively, but I *think* the '75 F that I flew in the 90's (my transition plane) had one. My '77 J does not. My '81 J salvage did have one, and I think I'm going to install it this weekend since I'm monkeying with the pitot-static system anyway.

Are you talking about the whiz wheel that allowed you to adjust for temp to present the TAS?

Sent from my iPad using Tapatalk

[PTK]

Google and Kathryn are your friends. Do your own research.

Seek and you shall find.

Here's a start

http://www.thekathrynreport.com/2010/04/pilot-killed-in-cessna-c210-crash.html?m=1

[Hank]

I will take your statement and raise it. Why does a 1970 C Model have a bottom of yellow at 170MPH and a VNE of 200 vs. my 1966 M20E? B.S. My "official" yellow bottom is 150 and not 170 and VNE is 189 NOT 200...NO Difference in the airframes like the E and F. I fly it like it was made in 1970...

Sometime in there the internal wing structure was changed, resulting in higher flap speeds. The rudder was lengthened, too.

 

In my 70 C, yellow starts at 170 175 mph. Vne = 200 mph.

Edited September 5, 2015 by Hank

[mpg]

Are you talking about the whiz wheel that allowed you to adjust for temp to present the TAS?

Sent from my iPad using Tapatalk

Yes,,, 

If the plane is "Built" with a "true" air speed indicator,,,   then you would be "required?" to dial in the

OAT and pressure altitude and read the "TAS".

[Marauder]

Yes,,,

If the plane is "Built" with a "true" air speed indicator,,, then you would be "required?" to dial in the

OAT and pressure altitude and read the "TAS".

I believe they were optional, but I'm not sure of the time frames. I can't remember definitively, but I *think* the '75 F that I flew in the 90's (my transition plane) had one. My '77 J does not. My '81 J salvage did have one, and I think I'm going to install it this weekend since I'm monkeying with the pitot-static system anyway.

My 1975 F never had one. Got one now, even automated!

Sent from my iPad using Tapatalk

[mpg]

My 1975 F never had one. Got one now, even automated!




Sent from my iPad using Tapatalk

Well now,,,    that is nice,  and slick,   And according to my trusty E6B it is Right!

 

Now my question about this automation is,,   does the VNE on the scrolled speed

showing now at 175,  adjust itself to a different speed on the scale as you 

fly higher and at different OAT?

[MyNameIsNobody]

Google and Kathryn are your friends. Do your own research.

Seek and you shall find.

Here's a start

http://www.thekathrynreport.com/2010/04/pilot-killed-in-cessna-c210-crash.html?m=1

You either have a sense of humor or you are being goofy with this.  You throw out a cryptic "Safety" statement and talk about planes just breaking up in decent and then say find your own research after you post a goofy thread about a crash in another country that may or may not have involved a bird strike.  Not good.

[MyNameIsNobody]

Sometime in there the internal wing structure was changed, resulting in higher flap speeds. The rudder was lengthened, too.

In my 70 C, yellow starts at 170 mph. Vne = 200 mph.

I would question what the flap and rudder have to do with yellow arc and VNE.  With regard to breaking the wings or tail off in decent.  We fly our planes in similar fashion on powered decent.  Crazy thrill seekers that we are

[mooniac15u]

Google and Kathryn are your friends. Do your own research.

Seek and you shall find.

Here's a start

http://www.thekathrynreport.com/2010/04/pilot-killed-in-cessna-c210-crash.html?m=1

There is no evidence whatsoever that the plane spontaneously broke apart while flying below Vne. 

[Marauder]

Well now,,,    that is nice,  and slick,   And according to my trusty E6B it is Right!

 

Now my question about this automation is,,   does the VNE on the scrolled speed

showing now at 175,  adjust itself to a different speed on the scale as you 

fly higher and at different OAT?

Nope.

[Deb]

From: http://www.flyingmag.com/technique/proficiency/technicalities-are-you-feeling-lucky

"The U.S. rules for certifying aircraft are found in several different locations, depending on the type of airplane, but Part 23 — a subpart of Title 14, Aeronautics and Space, of the Code of Federal Regulations — is typical. Descended from the earlier CAR 3, under which some types still in use today were certified, Part 23 came into force in 1965 and governs the certification of airplanes of up to 12,500 pounds gross weight, as well as commuter aircraft of up to 19,000 pounds. (Part 25, which is similar to Part 23 in many respects, applies to transport aircraft.) Light-sport aircraft are approved under a "consensus standard" developed by the American Society for Testing and Materials, a nongovernment body of experts that designs industry standards for just about everything; the ASTM standard, like other aircraft certification standards all over the world, is largely based on Part 23.

Section 335 of Part 23 defines several important speeds. The first is the design cruising speed, which, for airplanes with wing loadings of less than 20 pounds per square foot — that is, most small single-engine airplanes — must be 33 times the square root of the wing loading. For a wing loading of 16 psf, VC would be four times 33, or 132 kias. This speed is a purely formal requirement, used to provide a framework for structural and other decisions; many airplanes can't actually cruise at their "design cruising speed." But the design cruising speed provides a basis for another speed, VD, the design dive speed, which is generally 1.4 times VC; and VD is in turn the basis for VNE, the never-exceed speed, which is nine-tenths of VD. If an airplane can't achieve its design VD in flight, then the dive speed attained in flight test, VDF, replaces VD, and VNE is, again, nine-tenths of it.

These speeds, among others, define various corners of the flight envelope, which in turn determine the required strength of major structural components. But absolute speed affects many aspects of a structure besides obvious things like wing spars and fuselage skins. For example, cowlings must be sufficiently stiff to not bulge or blow apart under the internal pressure of ram air, which, at 175 knots, is about 100 pounds per square foot. Canopy latches and hinges must be strong enough to resist the considerable lift developed by a curved surface at high speed. Higher speeds imply lower angles of attack, and it's even conceivable that a wing with a lot of built-in washout or twist could fail above a certain speed because the angle of attack of the outer panels becomes negative, and they begin to push downward, subjecting the lower spar cap, which is the smaller, to an excessive compression load.

All of these loadings are due to air pressure, which grows in proportion to the square of the speed — double the speed produces four times the force; they are functions of the indicated airspeed, not the true. Now, VD, which is an indicated speed, is by definition a safe speed; the forces at VNE are just 81 percent of those at VD (0.9 x 0.9 = 0.81), and so there is a comfortable margin of safety, so far as structural strength is concerned, at VNE.

But there is a complication that muddies the water considerably. It is flutter. Flutter is a vibration that may be augmented by aerodynamic forces. It is the one challenge to aircraft structures that does not increase gradually with speed. It is possible for a structure to perform normally right up to a certain speed and then, with a gain of two or three more knots, to explode into fragments in a split second. That is what most likely happened to the South African VL-3. The accident has not yet been investigated, but it has the earmarks of wing flutter induced by a vibrating aileron.

Flutter is affected by a number of factors, one of which is the true, not the indicated, airspeed. As you will have immediately perceived, this fact raises a logical difficulty. VNE, the redline on the airspeed indicator, is an indicated airspeed, but the critical flutter speed may be a true airspeed. So the margin separating VNE from the critical flutter speed gets smaller as you gain altitude. Furthermore, if you get really high up, the difference can be larger than the margin that separates VD from VNE, simply because the difference between indicated and true airspeed is greater than 10 percent.

That doesn't mean the airplane will flutter, because VD is not the critical flutter speed. Manufacturers are not required to determine the critical flutter speed for each design, but only to demonstrate that it is free of flutter up to VD and that there is good reason to believe, based on various kinds of ground tests and mathematical analyses, that it will remain so up to 1.2 times VD. It is noteworthy that the section of Part 23 regarding flutter, 23.629, makes no mention of altitude. The cumulative margin between VNE and 1.2 times VD is 33 percent, and this probably provides a good cushion in all normal operations, but if I were to ride a wave to 35,000 feet in a 172, I would not be in a hurry to peg the airspeed at redline on the way back down."

 

So, there are many factors that go into determining V speeds, including Vne. Vne is then presented to the pilot in the airspeed limitation sections and airspeed markings in the POH (or AFM). In our Mooney, these are KIAS, and are indicated on our airspeed indicator in KIAS.

As an aside, Vne is defined as "NEVER EXCEED SPEED – The speed limit that may not be exceeded at any time." This definition does not indicate how this is presented to the pilot, but in the case of our Mooney, the POH (AFM) does.

Can we agree that determining Vne (from a builder's perspective) is complex and depends on a myriad of factors, but the presentation to us by Mooney is a defined redline number in IAS?

Edit: One hopes our airframes have been tested at the maximum altitude the engine can take it to...

[Marauder]

From: http://www.flyingmag.com/technique/proficiency/technicalities-are-you-feeling-lucky

"The U.S. rules for certifying aircraft are found in several different locations, depending on the type of airplane, but Part 23 — a subpart of Title 14, Aeronautics and Space, of the Code of Federal Regulations — is typical. Descended from the earlier CAR 3, under which some types still in use today were certified, Part 23 came into force in 1965 and governs the certification of airplanes of up to 12,500 pounds gross weight, as well as commuter aircraft of up to 19,000 pounds. (Part 25, which is similar to Part 23 in many respects, applies to transport aircraft.) Light-sport aircraft are approved under a "consensus standard" developed by the American Society for Testing and Materials, a nongovernment body of experts that designs industry standards for just about everything; the ASTM standard, like other aircraft certification standards all over the world, is largely based on Part 23.

Section 335 of Part 23 defines several important speeds. The first is the design cruising speed, which, for airplanes with wing loadings of less than 20 pounds per square foot — that is, most small single-engine airplanes — must be 33 times the square root of the wing loading. For a wing loading of 16 psf, VC would be four times 33, or 132 kias. This speed is a purely formal requirement, used to provide a framework for structural and other decisions; many airplanes can't actually cruise at their "design cruising speed." But the design cruising speed provides a basis for another speed, VD, the design dive speed, which is generally 1.4 times VC; and VD is in turn the basis for VNE, the never-exceed speed, which is nine-tenths of VD. If an airplane can't achieve its design VD in flight, then the dive speed attained in flight test, VDF, replaces VD, and VNE is, again, nine-tenths of it.

These speeds, among others, define various corners of the flight envelope, which in turn determine the required strength of major structural components. But absolute speed affects many aspects of a structure besides obvious things like wing spars and fuselage skins. For example, cowlings must be sufficiently stiff to not bulge or blow apart under the internal pressure of ram air, which, at 175 knots, is about 100 pounds per square foot. Canopy latches and hinges must be strong enough to resist the considerable lift developed by a curved surface at high speed. Higher speeds imply lower angles of attack, and it's even conceivable that a wing with a lot of built-in washout or twist could fail above a certain speed because the angle of attack of the outer panels becomes negative, and they begin to push downward, subjecting the lower spar cap, which is the smaller, to an excessive compression load.

All of these loadings are due to air pressure, which grows in proportion to the square of the speed — double the speed produces four times the force; they are functions of the indicated airspeed, not the true. Now, VD, which is an indicated speed, is by definition a safe speed; the forces at VNE are just 81 percent of those at VD (0.9 x 0.9 = 0.81), and so there is a comfortable margin of safety, so far as structural strength is concerned, at VNE.

But there is a complication that muddies the water considerably. It is flutter. Flutter is a vibration that may be augmented by aerodynamic forces. It is the one challenge to aircraft structures that does not increase gradually with speed. It is possible for a structure to perform normally right up to a certain speed and then, with a gain of two or three more knots, to explode into fragments in a split second. That is what most likely happened to the South African VL-3. The accident has not yet been investigated, but it has the earmarks of wing flutter induced by a vibrating aileron.

Flutter is affected by a number of factors, one of which is the true, not the indicated, airspeed. As you will have immediately perceived, this fact raises a logical difficulty. VNE, the redline on the airspeed indicator, is an indicated airspeed, but the critical flutter speed may be a true airspeed. So the margin separating VNE from the critical flutter speed gets smaller as you gain altitude. Furthermore, if you get really high up, the difference can be larger than the margin that separates VD from VNE, simply because the difference between indicated and true airspeed is greater than 10 percent.

That doesn't mean the airplane will flutter, because VD is not the critical flutter speed. Manufacturers are not required to determine the critical flutter speed for each design, but only to demonstrate that it is free of flutter up to VD and that there is good reason to believe, based on various kinds of ground tests and mathematical analyses, that it will remain so up to 1.2 times VD. It is noteworthy that the section of Part 23 regarding flutter, 23.629, makes no mention of altitude. The cumulative margin between VNE and 1.2 times VD is 33 percent, and this probably provides a good cushion in all normal operations, but if I were to ride a wave to 35,000 feet in a 172, I would not be in a hurry to peg the airspeed at redline on the way back down."

 

So, there are many factors that go into determining V speeds, including Vne. Vne is then presented to the pilot in the airspeed limitation sections and airspeed markings in the POH (or AFM). In our Mooney, these are KIAS, and are indicated on our airspeed indicator in KIAS.

As an aside, Vne is defined as "NEVER EXCEED SPEED – The speed limit that may not be exceeded at any time." This definition does not indicate how this is presented to the pilot, but in the case of our Mooney, the POH (AFM) does.

Can we agree that determining Vne (from a builder's perspective) is complex and depends on a myriad of factors, but the presentation to us by Mooney is a defined redline number in IAS?

Edit: One hopes the airframe has been tested at the maximum altitude the engine can take it to, or a maximum altitude limitation has been defined.

So, after reading this, my original hypothesis is correct, "Don't go too fast" and to determine TRUE flutter speed from this theoretical discussion, Peter needs to demonstrate for us when flutter occurs by borrowing my cameras and filming a dive from 15,000'.

[EMB]

So, after reading this, my original hypothesis is correct, "Don't go too fast" and to determine TRUE flutter speed from this theoretical discussion, Peter needs to demonstrate for us when flutter occurs by borrowing my cameras and filming a dive from 15,000'.

 

Don't forget to bring your parachute Peter.

Edited September 5, 2015 by EMB
Huh - what happened here - this entire website has changed over night. This is aviatoreb - Erik Bollt - and yet everything about my avatar, my picture (copilot bear) my signature block etc is all lost. And the emb it assigned me says I am a newbie.

[MyNameIsNobody]

There are a lot of semantical egos at work here.  I learned that the VNE of my same model of plane increased the yellow bottom and VNE speed.  I fly my plane a lot in the yellow based on the airspeed indicator markings at the time it was manufactured.  I have some validation that my plane is "stronger than I thought".  I operate the plane never exceeding my VNE.  I like "thinking", right or wrong that my plane was overbuilt and I have added margins for safety.  

I flat DON'T LIKE when I am told without real scientific proof that I am operating my aircraft in an unsafe manner.  If pilots want to be more conservative in their decent...Fine.  Don't make me out to be flying on the edge of safety to "make up climb time" when I decend within operating envelope in clear, non-turbulent air.

Edited September 5, 2015 by MyNameIsNobody

[Shadrach]

Google and Kathryn are your friends. Do your own research.

 

Seek and you shall find.

 

Here's a start

 

http://www.thekathrynreport.com/2010/04/pilot-killed-in-cessna-c210-crash.html?m=1

YHGTBFSM....   That's not a start. It's a pathetic attempt to see a specific cause in a very general report. 

 I truly try to understand your point of view Peter.  I think we all agree that minding Vne is important.   However, on several occasions I have observed how you respond to reasoned criticism/disagreement. Whenever the facts get in the way of your viewpoint, you often "jump the shark" trying to bolster your stance citing scenarios that don't offer correlation much less the causation needed to support your viewpoint.

Edited September 6, 2015 by Shadrach

[DS1980]

Actually, it is...

At least I'm not suggesting somebody take their airplane to 15,000 feet and kill themselves to determine the flutter speed of their aircraft.

Too far.

Edited September 6, 2015 by DS1980

[MyNameIsNobody]

Didn't I read "bring/take your parachute"...

[Shadrach]

At least I'm not suggesting somebody take their airplane to 15,000 feet and kill themselves to determine the flutter speed of their aircraft.

Too far.

 

Yes, I think you should call the Feds as that was clearly a serious recommendation and not meant in jest. Chris is already known for his visual assaults in these forums and he has now graduated to encouraging a pilot to dive his airplane to oblivion. 

PETER, IF YOU ARE STILL WITH US, DON'T DO IT. CHRIS DIDN'T MEAN IT!!!  OH THE HUMANITY!!!

Edited September 6, 2015 by Shadrach

[philiplane]

Don't worry how strong the wing is, because the tail will fail long before you reach the limits of the wing.

[MyNameIsNobody]

I couldn't sleep last night due to guilt and visual of Peter diving to his demise...and the hundreds...maybe thousands of fuel tank changes sans boost pump.  I now live in a world of dread.  The horror...

[DS1980]

A place of learning........

How do the last few posts promote this?