How strong is the M20 wing?

[MyNameIsNobody]

I was quoting from memory and got my Vne wrong.

Uh Oh, there's the first....Nevermind, forgot what I was going to say...

[Guest]

It would be interesting to find out how many G's it takes to break the Mooney wing. I know I hit the ground hard enough last year in a bravo to have snapped it at the fuselage. Man, that hurt.

Stacey, got your ears on? any Engineering data to share? Ill ask Bob Kromer at the Mooney Summit for sure to see if he knows.

 

mike "cementhead" elliott

Thankfully Mike your body seems even tougher than a Mooney.

Glad you're here with us.

Clarence

[MyNameIsNobody]

Here's an M20K that broke up due to flutter. It sounds like the folks at Mooney predicted the onset of flutter to occur at 241 knots.

http://aviation-safety.net/wikibase/wiki.php?id=36780

Good read/Bad read. Good to know info. Bad day. Was this a Rocket conversion?

[mike_elliott]

Thankfully Mike your body seems even tougher than a Mooney.

Glad you're here with us.

Clarence

Thank you Clarence. I really did get busted up pretty badly, and if it were not for my now wife (wasn't at the time, we got married in the pulmonary unit while I was recovering), I probably would not have made it. She was truly an inspiration. Alice is in charge of the Bill Gilliland foundation we have set up as part of the Mooney Summit, Inc. to provide crisis intervention and financial need assistance for downed Mooney Pilots' families. A licensed therapist, she has been there, done that, and will roll out this great charity.

More will be announced at the Mooney Summit III next month.

[Guest]

Here is the Mooney Type Cerficate link:

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/cd54a24fc81bae1c86257df20054b12c/$FILE/2A3_Rev_56.pdf

Might be a good review to find your model, all speeds are listed

All of the talk of flutter speeds is of course based on new airplanes with all new non worn parts in the flight control systems and of course all flight controls are balance. If your plane has been painted were the controls balanced?

Clarence

[PTK]

Here's an M20K that broke up due to flutter. It sounds like the folks at Mooney predicted the onset of flutter to occur at 241 knots.

http://aviation-safety.net/wikibase/wiki.php?id=36780

The way I read it at an altitude somewhete lower than 19k I'm not so sure it was flutter. More likely it was structural failure due to excessive speed beyond Vne.

[mooniac15u]

Good read/Bad read. Good to know info. Bad day. Was this a Rocket conversion?

Yes, it was a Rocket conversion. Here's the full NTSB narrative with additional info:

http://www.ntsb.gov/_layouts/ntsb.aviation/brief2.aspx?ev_id=20001211X10119&ntsbno=LAX98FA154&akey=1

[mooniac15u]

The way I read it at an altitude somewhete lower than 19k I'm not so sure it was flutter. More likely it was structural failure due to excessive speed beyond Vne.

You didn't read this to mean flutter?

" CAUSE: The pilot's operation of the airplane at a speed well in excess of it's designed never exceed speed that resulted in elevator flutter and in-flight failure of the airplane. Turbulence and icing conditions were factors in the accident."

[PTK]

You didn't read this to mean flutter?

" CAUSE: The pilot's operation of the airplane at a speed well in excess of it's designed never exceed speed that resulted in elevator flutter and in-flight failure of the airplane. Turbulence and icing conditions were factors in the accident."

Yes, but look at the altitude. It was somewhere lower than 19K feet. I associate flutter at higher altitudes where TAS is excessive, the pilot is fooled by a lying ASI and the thin air does not dampen oscillations as thicker air down lower would.

[cnoe]

Here's an M20K that broke up due to flutter. It sounds like the folks at Mooney predicted the onset of flutter to occur at 241 knots.

http://aviation-safety.net/wikibase/wiki.php?id=36780

 

Yes, it was a Rocket conversion. Here's the full NTSB narrative with additional info:

http://www.ntsb.gov/_layouts/ntsb.aviation/brief2.aspx?ev_id=20001211X10119&ntsbno=LAX98FA154&akey=1

 

Thanks for the info guys; this is very interesting indeed. The full NTSB narrative says that Mooney lists ~240 knots as the speed at which flutter might emerge. But what's really scary is the description of the flutter identified in the investigation. The report said...

 

An FAA airframe specialist from the Ft. Worth, Texas, Airplane Certification Office, examined the recovered wreckage. In part, the specialist noted the following: 1) There was no indication from the structural fractures of corrosion or fatigue failure being present; 2) Both horizontal tail surfaces and elevators left the airplane in the air. The right side did a negative/positive cycle to come up and hit the vertical tail and rudder. The left side only indicated a positive cycle up and back; 3) Both the left and right elevator balance weight horns were missing and appeared to have separated from the elevators prior to ground impact;

 

I can say with certainty that if things get so bad that your horizontal stabilizer whips high enough to contact the vertical stabilizer your day will not end on a positive note. Very sobering.

 

I'm not sure where the 300 mph Mooney test story came from but I plan to stay below Vne if at all possible based on this one accident description.

[mooniac15u]

Yes, but look at the altitude. It was somewhere lower than 19K feet. I associate flutter at higher altitudes where TAS is excessive, the pilot is fooled by a lying ASI and the thin air does not dampen oscillations as thicker air down lower would.

 

Perhaps that's what this pilot thought as well.  It didn't work out very well for him.

[PTK]

I tend to think of structural stress and flutter as the two distinct and different phenomena they are.

[mooniac15u]

I tend to think of structural stress and flutter as the two distinct and different phenomena they are.

 

Yes, they are different.  In the full narrative both Mooney and the FAA concluded it was flutter.  I think I'll go with the experts.

[mooniac15u]

At any rate, there are probably two key takeaways from this:

 

1) Mooneys can and do break up in flight.

2) Mooney expects the onset of flutter to be around 240 knots in the mid body airframe.

[carl]

189 mph is the Vne . Yep, I have the same POH , LASAR has performance listed , Where I quoted 197. 

 

 

 Im slowing down.

carl

[Shadrach]

For whatever reason, the F of the same year as yours has a yellow line at 175MPH and redline at 200MPH.  According to the TCDS Vno and Vne for the E model very by serial number... 

[Shadrach]

At any rate, there are probably two key takeaways from this:

 

1) Mooneys can and do break up in flight.

2) Mooney expects the onset of flutter to be around 240 knots in the mid body airframe.

 

I believe that redline on the M20TN is 240kts.

[MyNameIsNobody]

O.K. The pilot reported that he was "at 2900 feet", right? How did the plane break-up at 8-9k feet if he was at 2900? Weird. He was either lying on his altitude at report and diving to get there and it got out of hand or he got into severe updraft with the weather? Or what? I am not understanding what happened there?

What are your interpretations of what happened in that plane on that date to produce that result? Obviously he got into a dive and the elevators failed resulting in a break-up of the wing, but why did he get over 240knots? Spacial disorientation? That weird weather/cell that was NOT as described by official weather, but included heavy rain and wind?

Pretty awful to read. No way to go out...Just not understanding this one.

SAD.

[mooniac15u]

O.K. The pilot reported that he was "at 2900 feet", right? How did the plane break-up at 8-9k feet if he was at 2900? Weird. He was either lying on his altitude at report and diving to get there and it got out of hand or he got into severe updraft with the weather? Or what? I am not understanding what happened there?

What are your interpretations of what happened in that plane on that date to produce that result? Obviously he got into a dive and the elevators failed resulting in a break-up of the wing, but why did he get over 240knots? Spacial disorientation? That weird weather/cell that was NOT as described by official weather, but included heavy rain and wind?

Pretty awful to read. No way to go out...Just not understanding this one.

SAD.

 

I don't think he reported being at 2900 feet.  I think he just read back a clearance to descend to 2300 feet.

 

"At 0929:35, the pilot was cleared to descend and maintain 2,300 feet. The pilot responded at 0929:40 by stating "down to two thousand three hundred one bravo yankee." No further communications were recorded from the pilot."

 

5 seconds earlier he reported descending through 10,200.

 

"At 0929:30, the pilot indicated that he was descending through 10,200 feet. "

[cnoe]

The last reported altitude from the pilot was at 10,200 msl descending. He acknowledged the clearance to 2,300 msl but was still at altitude at that point. Ceilings near that time were reported as broken at 5,500 and 7,000 with the freezing level at 7,000.

It's only speculation but perhaps he iced up and/or suffered spatial disorientation during the descent? The 3,500 fpm descent observed by ATC was obviously the source of his excess speed.

This was exactly the point of my original question, what action to take if you find yourself in this situation. I now believe the correct answer is to PULL SOON and PULL HARD to arrest the acceleration ASAP. Sounds like the wings are unlikely to fall off as long as flutter doesn't remove the tail first.

Sent from my iPad using Tapatalk

[carusoam]

I'm not a believer in the pull hard theory, CNOE...

Once exceeding maneuvering speed, pulling back hard would bring the elevator to full up position.....

It's not like you are stepping on ABS brakes. Maneuvering speed dictates what can be done with the flight controls. Full deflection of the flight controls above manuevering speed is probably not proper.

A well balanced plane will load up stresses when you make large changes quickly at high speeds.

I agree with the part about starting to make changes quickly. Remove power, level wings, begin the slowing down process....

Use Janet Yellen's financial advice applied to aviation... Be data dependent, and move at a measured pace...

It could be my misinterpretation of your typing.

Check with a flight instructor to discuss your concerns. Get a better understanding of maneuvering speed and how it effects your next decision steps.

If I misunderstood your point, I apologize in advance...

I am not a CFI.

The importance of avoiding situations like icing and storms while aloft is the best part of the conversation. The best way to get out of this trouble is to not get into it. If you are in it while talking to ATC you want to relay your needs with them. Ice collects quickly start getting to a place where ice isn't. Use ATC to help with that.

Ice has many ill effects as it starts to collect.

1) Plane's weight increases

2) wing's lift is affected

3) pitot and static info may be effected by ice blockage.

4) static build up can add to communication and nav challenges.

5) thrust and prop balance can be affected

Don't wander into icing conditions. If you do, make wise decisions on how to get out. Ask for help. Don't rush...

Trying to help.

Best regards,

-a-

[Deb]

Assuming you didn't move the trim, I wouldn't pull at all. If you level the wings, you would probably end up pushing pretty hard as the wing will seek it's trimmed speed resulting in a huge pitch up.

CNOE,

Mark makes a good point.

There is a dicussion of this here, as it relates to the Pilatus accident last year:

http://www.flyingmag.com/technique/accidents/revisiting-pc-12-crash

And:

http://www.flyingmag.com/technique/accidents/aftermath-first-fly-airplane

"It is possible to recover, even from a 340-knot spiral, if you roll the wings level while trimming nose-down to relieve G forces."

And

"The essential point, however, is to limit G while reducing speed. If the plane were going to come apart because of sheer speed, it would already have done so. It's the G-forces that pilots apply in their urgency to stop pointing downward that end up breaking wings."

[RobertGary1]

The problem is that the G's required to recover are related to speed. So while nose down gaining speed the longer it takes to arrest the acceleration the higher the minimum G's required to pull out.

[ryoder]

Is flying a C in the bottom of the yellow while in mildly bumpy air hard on the airplane like driving an old IROC Z just over the speed limit on a bumpy road? I assume it is.

[Guest]

Isn't maneuvering speed the point where maximum deflection of the flight controls will not lead to over stress of the airframe? Then G tolerance lowers as speed increases.

Question for the high altitude jet pilots, as the plane climbs to higher altitudes the barber pole winds lower, lowering VNE shrinking the operational envelopes? While our plane do not have the moving barber pole, does the same thing not effect turbo charged high flyers?

Clarence