How strong is the M20 wing?

[Bob_Belville]

PTK and DS 1980,

You are absolutely correct that flutter is a function of TAS, but flutter speed and Vne are not interchangeable terms.

As others have pointed out Vne is clearly defined as an IAS.

In a certificated airplane operated within it's envelope, Vne will protect you from flutter (and other bogeymen). There is no need to calculate TAS or density altitude, just keep the white needle below the red radial and all the pieces should stay attached to the airplane.

I hope these confident assurances are correct. But I sure would like to see someone provide some authority for assertion that diving a plane at a TAS higher than Vne is legal/safe/wise... 

[Bob_Belville]

I would bet dollars to donuts that Bill Wheat has ridden the M20 airframe down from altitude at speeds that would make your Vne look slow.

Well, Bill is in declining health, but Bob Kromer is going to be at Mike & Ron's shindig in a few weeks, maybe we can engage him in flight testing war stories.

[Shadrach]

Does anyone know what True Indicated Airspeed is?

[Shadrach]

Well, Bill is in declining health, but Bob Kromer is going to be at Mike & Ron's shindig in a few weeks, maybe we can engage him in flight testing war stories.

 

If you're there, do ask him!!!

[Bob_Belville]

Does anyone know what True Indicated Airspeed is?

Ms. Google, who knows everything, doesn't seem to have any acquaintance with that term.

[aviatoreb]

Does anyone know what True Indicated Airspeed is?

 

If someone asks you how fast you are going you can either a) tell a lie, or   tell the truth.  If you choose b, then you have told your true air speed.  The answer to a) would be is your false air speed.  If you choose c) all of the above, then this would be your unsure speed.

[Bob_Belville]

Well, Bill is in declining health, but Bob Kromer is going to be at Mike & Ron's shindig in a few weeks, maybe we can engage him in flight testing war stories.

https://www.facebook.com/williambill.wheat

[Shadrach]

Ms. Google, who knows everything, doesn't seem to have any acquaintance with that term.

 

 

I know that.  It's odd that the factory used in the early TCDS and then dropped the "true" portion on later models. I can see why folks are confused.

[mooniac15u]

Does anyone know what True Indicated Airspeed is?

 

It's an old CAR 3 term that is synonymous with Calibrated Airspeed.

 

3.46 (b ) "True indicated" or "calibrated" air speed for performance and operating purposes equal to indicator reading corrected for position and instrument errors.

[Shadrach]

If someone asks you how fast you are going you can either a) tell a lie, or tell the truth.  If you choose b, then you have told your true air speed.  The answer to a) would be is your false air speed.  If you choose c) all of the above, then this would be your unsure speed.

 

 

There's a lot of a) going on around these parts!

[Super Dave]

I hope these confident assurances are correct. But I sure would like to see someone provide some authority for assertion that diving a plane at a TAS higher than Vne is legal/safe/wise...

Safe and wise takes some judgement; in smooth air you could descend right at Vne, but a bump or gust could put the white needle on the wrong side of the red radial, and that might wake up the bogeyman.

I don't know if it lends me any authority, but I used to be the Chief Flight Instructor for a university aviation program, where I instructed and signed off many Initial CFI applicants. I also taught an aviation class at the University. Currently fly jets as a corporate pilot.

[Shadrach]

It's an old CAR 3 term that is synonymous with Calibrated Airspeed.

 

3.46 (b ) "True indicated" or "calibrated" air speed for performance and operating purposes equal to indicator reading corrected for position and instrument errors.

 

Thanks! If that is the case, than per the TCDS, Vne is in calibrated airspeed for the all the birds prior to the J at which time it became Indicated airspeed.  

 

My biggest take away from this thread is that either the factory or the certification process was a complete "Cluster F@%#" in the 60s. There is a lot to be desired in terms of consistency from model to model. Why does an E model that was built on the same line at the same time, sharing all of the same components as my bird save for a few inches of sheet metal run into Vno 25mph sooner, Vne 11MPH sooner?

[DS1980]

Show us please! Everyone agrees the true airspeed has the largest impact on flutter. However we're not talking about flutter, we're talking about Vne which has a whole host of design limits incorporated into it. So show me something regulatory that tells us Vne is a TAS number. If you can do that I will happily agree with you. This post has included screenshots of the TCDS, the relevant FAR's and then a bunch of people on the internet contradicting The FAR with no documentation to back it up.

I'm happy to agree with you and Pete, if you give us something other than your opinion. Show me something regulatory!

Nah, you've already made your mind up.

You've gone this long without killing yourself, so I don't see it as an issue of satey.

[Shadrach]

Nah, you've already made your mind up.

You've gone this long without killing yourself, so I don't see it as an issue of satey.

 

That is a cop out my friend. You made the statement. Have the courage of your convictions to show us why you're correct, or at least why you believed you were correct.  It's what make a forum a learning environment.

[DS1980]

Not a cop out. It's choosing battles.

This was already extensively covered in a previous thread.

mooniac15u....remember me???

 

Vne is by far the most confusing speed. It's marked on the indicator because it has to be. How it's calculated and what it's derived from isn't always clear.

Yes, it's an IAS, but it does have TAS considerations. And it does change with conditions.

 

I had my fun.

 

Pete, you're not wrong, and you're not right. There's only a few people from every manufacturer that knows the story of how they decided on the Vne of their airplane. 
 

The bottom line of Vne is that it will keep you safe if you're below the service ceiling of your plane.

[Hank]

"This is my opinion. Someone prove me wrong with 'proof' that I will accept."

C'mon, folks, what is more definitive than the TCDS? It's already been both posted as a link and quoted. Keep the pointy white needle at or below the redline IAS and your plane won't break in smooth air, barring large control movements. Keep below Va for your weight, and turbulence or one maximum control deflection won't break your plane.

I descend power on, all the time, from wherever I am, to pattern altitude at 500 fpm, sometimes briefly faster, which typically has me just below the yellow (3-5 mph below). If it's too bumpy, I slow down for comfort, not safety.

I have practiced emergency descents at higher speeds, and spiraling at lower IAS nearly pegging the VSI. Only made one trip to O2 territory, for handling and emergency descent practice. 15,000 msl was 18,800 calculated DA. No problemo.

[jetdriven]

people slow to Va all the time in rough air but it's only maneuvering speed. One where a full control deflection won't cause structural damage. The top of the green arc is Vno. That's the speed at which an instantaneous 1800 FPM vertical gust can cause damage. The redline guarantees you half that. Far 23 airplanes are stronger yet. 3000 FPM at top of green arc and half that at design dive speed, 10% beyond Vne.

Just dont exceed the green arc in heavy turbulence and don't yank on the controls.

[mooniac15u]

Thanks! If that is the case, than per the TCDS, Vne is in calibrated airspeed for the all the birds prior to the J at which time it became Indicated airspeed.  

 

My biggest take away from this thread is that either the factory or the certification process was a complete "Cluster F@%#" in the 60s. There is a lot to be desired in terms of consistency from model to model. Why does an E model that was built on the same line at the same time, sharing all of the same components as my bird save for a few inches of sheet metal run into Vno 25mph sooner, Vne 11MPH sooner?

 

The E and F have different max weights and different wing loading.  Vne is ultimately derived from Vc which is calculated from wing loading.

[Shadrach]

The E and F have different max weights and different wing loading.  Vne is ultimately derived from Vc which is calculated from wing loading.

Agreed, and that would explain the differences if not for the fact that sometime in the 70's, the C, E, F and J all got the same Vspeeds despite their differences in wing loading and MGW.

[mooniac15u]

Agreed, and that would explain the differences if not for the fact that sometime in the 70's, the C, E, F and J all got the same Vspeeds despite their differences in wing loading and MGW.

 

Part 23.335 (and CAR 3) formulae generally provide a minimum value.  They both have a provision for demonstrating a higher dive speed that supersedes the calculation.  I ran some calculations and the Vne for the early E's looks like it comes from the wing loading formula.  For the later serial numbers I would guess that they demonstrated a higher dive speed.

[Shadrach]

Not a cop out.

Actually, it is...

[PTK]

Not a cop out. It's choosing battles.

This was already extensively covered in a previous thread.

mooniac15u....remember me???

Vne is by far the most confusing speed. It's marked on the indicator because it has to be. How it's calculated and what it's derived from isn't always clear.

Yes, it's an IAS, but it does have TAS considerations. And it does change with conditions.

I had my fun.

Pete, you're not wrong, and you're not right. There's only a few people from every manufacturer that knows the story of how they decided on the Vne of their airplane.

The bottom line of Vne is that it will keep you safe if you're below the service ceiling of your plane.

It's really not that confusing at all!

And it's not about who's right or wrong! It's about being safe.

You know what's really interesting? There have been certificated airplanes that have come apart with their pilots doing what we all have probably done: attempt to get back in descent speed lost in the climb. They were in smooth air at or below Vne thinking they're safe!

The only parameter we have control over is our TAS!

[Shadrach]

It's really not that confusing at all!

And it's not about who's right or wrong! It's about being safe.

You know what's really interesting? There have been certificated airplanes that have come apart with their pilots doing what we all have probably done: attempt to get back in descent speed lost in the climb. They were in smooth air at or below Vne thinking they're safe!

The only parameter we have control over is our TAS!

Could you link a few accident reports regarding these smooth air disintegrations while below Vne?

[MyNameIsNobody]

Thanks! If that is the case, than per the TCDS, Vne is in calibrated airspeed for the all the birds prior to the J at which time it became Indicated airspeed.

My biggest take away from this thread is that either the factory or the certification process was a complete "Cluster F@%#" in the 60s. There is a lot to be desired in terms of consistency from model to model. Why does an E model that was built on the same line at the same time, sharing all of the same components as my bird save for a few inches of sheet metal run into Vno 25mph sooner, Vne 11MPH sooner?

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...

[MyNameIsNobody]

It's really not that confusing at all!

And it's not about who's right or wrong! It's about being safe.

You know what's really interesting? There have been certificated airplanes that have come apart with their pilots doing what we all have probably done: attempt to get back in descent speed lost in the climb. They were in smooth air at or below Vne thinking they're safe!

The only parameter we have control over is our TAS!

B.S. Don't roll that out without giving clip of scenario Peter. I call shenanigans!