Turbulence + V = chicken

[jetdriven]

On 5/11/2018 at 9:52 AM, Jerry 5TJ said:

Vertical gusts independent of control inputs can overload the structure.  

that is a sharp edged vertical gust of 30 FPS at the top of the yellow arc. Thats turbulence induced structural damage. But Va and Vno are two very different things. If you dont apply ham-fisted control inputs, its nearly impossible to damage the airplane inside the green arc. And it takes a lot more than summertime bumps to bend anything below redline.  So lest not get confused, Va and control inputs are one thing, Vno (top of green arc) and turbulence is another.  

[Bartman]

If I know I am going to be flying in turbulence I always fill the tanks and make her as heavy as practical.  In addition to just riding it out and not trying to hold altitude dead on ask for block altitude and it is usually granted in this part of the country.  Also sometimes I do get tense and have to remind myself to relax the butt cheeks.  It does help...some.

[Jerry 5TJ]

Those precise load charts are accurate — but is there anything special about 30 FPS?  I’ve seen those load charts drawn for 25, and 50 FPS gusts as well. Even 100 FPS is “only” 6,000 feet per minute & in convective processes that velocity is not uncommon, I read.  

Maneuvering speed seems, to me, to be a general cautionary warning based on a generic assumption of what gust velocity might be found. 

 

[Skates97]

On 5/11/2018 at 10:31 AM, rpcc said:

Skates - I really enjoyed reading this book.  The discussion on Va was interesting.  I'm sure someone here will comment on how accurate this is for M20 airframes.  In the thread I reference, polito mentions 120kts as a guideline for light weight Va.  https://www.amazon.com/Flying-Beech-Bonanza-John-Eckalbar/dp/0961654430

120kts is 138mph (everything in my plane and POH is in mph so that's what I use and think in) which is higher than what Va is for my plane... 

If I was worried about rough air breaking my plane I would get a different plane to fly or not fly at all. As Ken has said, summertime flying in the west can make for some bouncing around, although I'm glad I haven't had any like the couple of experiences he just mentioned. One of the reasons I got a Mooney was because of the structural strength of the plane, even if it is 54 years old. I'm confident it can handle more than I can. 

[rpcc]

I'm glad you are not worried.   Just saw the number you stated and thought it was lower.  

[ilovecornfields]

4 hours ago, Bartman said:

If I know I am going to be flying in turbulence I always fill the tanks and make her as heavy as practical.  In addition to just riding it out and not trying to hold altitude dead on ask for block altitude and it is usually granted in this part of the country.  Also sometimes I do get tense and have to remind myself to relax the butt cheeks.  It does help...some.

I've been told to do the opposite because a lightly loaded airplane  will have less loads placed on it than an heavier airplane. Maybe someone with more knowledge can comment.

 

This is from mountainflying.com: (https://www.mountainflying.com/pages/mountain-flying/turb_va.html)

MISCONCEPTION

Pilots notice that a heavily loaded airplane rides smoother in turbulent air. They perceive this as an indication that the airplane should be loaded to its maximum whenever turbulence is expected. This is a bad assumption.

Consider an airplane that has a maximum allowable gross weight of 3,000 pounds. If it encounters a +30 fps gust that results in an additional 2-g load factor, the airplane experiences a total of 3 Gs load factor. Multiply the 3-g load factor by 3,000 pounds and the wings are supporting 9,000 pounds.

Assume the airplane is loaded to 1,500 pounds and that it is subjected to the same gust. With half the inertia, the gust acceleration is doubled, causing the airplane to experience a 5-g load factor (4-g force plus 1-g level flight). Multiply 1,500 pounds by 5 gs and the wings are supporting 7,500 pounds.

The lightly loaded airplane is subjected to 1,500 pounds less load when encountering the same gust. Even though the heavy airplane realizes less load factor, it incurs more strain. The pilot recognizes load factor; the airplane recognizes load.

 

Barry Schiff also wrote a nice summary on flying in turbulence: https://www.aopa.org/news-and-media/all-news/2018/january/pilot/proficient-pilot-turbulent-advice

[carusoam]

ILC,

Something is getting missed....

How does a pilot change his gross weight before he flys into unexpected turbulence?

Often, the writing for the masses covers ordinary flying to a 100 dollar hamburger...  Mooney flying often involves long distances over tough terrain and around thunderstorms.... writing for the masses won’t usually cover the things that will save your life... until they have to... The Scott Crossfield story...

 

The maneuvering speed is weight and speed based... what you are using makes sense to some extent...under ordinary conditions...  

thunderstorms and mountain waves are not ordinary conditions... (There is more to what those fine authors have given in those articles...)

 

Because...

Plan A: When encountering a brick wall of changing airflow... the wing will stall with the sudden change of AOA...

If the wing doesn’t stall it is then exposed to the full forces of vertical acceleration...

 

Follow this logic...

Using Jerry’s number of 6000 fpm.... a pretty scary ride when it’s +6000 fpm... a pretty terrify ride if it’s -6000 fpm...

Picturing flying towards an invisible column of air that is moving vertically 6,000 fpm... (building thunderstorm activity)

That is 68 mph...!

your plane flying in the yellow arc, is going to be forced to accelerate from 0 to 68 mph in about the length of your plane... you might get some warning of the windshear, but it will be hidden in a lot of smaller bumps...

 

if the plane isn’t traveling slow enough to stall...

That is going to feel like a crash, and bend metal like a crash... without hitting anything solid... how much the plane weighs is of little consequence if it didn’t stall... unless unflyable comes in different levels... bent and unflyable vs. broken and unflyable... 

 

Hard to believe that a random stall at altitude, is the better option than flying quickly to escape the area...  (a common type of trap)

 

Turbulence is caused by so many things... wind and mountains, or heat and weather...

it will really help to know what is causing the wind shear, to know how strong the wind shear is going to be.  Mountains and windy days and thunderstorms nearby are a must to be going slow... you won’t see it before running into it...

If you haven’t slowed by the time the iPad has been seen floating by... it is time to slow down, now...

 

i am hoping this idea of slowing to naneuvering speed with this long logic piece makes it understandable.  The plane designers give these numbers on purpose.  They don’t have tests that they can fly through that gives the numbers...

Other design quirks... why show the strength of the main wing, and avoid discussing the other flying wing back there....?  That is what the B company has a problem with...

PP thoughts, but really a CFI is better to explain it... i’m Not a CFI...

Best regards,

-a-

[carusoam]

It would be nice if we could always avoid turbulence...

It is as easy as avoiding VFR flight into IMC...

Or flying into icing conditions..

Or departing into high DA from a short runway...

Or climbing into a departure stall...

or a complete list of other accidental occurrences.

 

We have a tool, just need to know when to use it. Before it is needed... 

keep in mind... when your fully loaded plane runs into turbulence.... nobody is going to like it when you start throwing things overboard to have a lighter GW.

Best regards,

-a-

[steingar]

Hard to believe folks in Texas would make an airplane that could be easily broken by turbulence.

 

To put another spin on that, lots of these aircraft have been flying around for 50 years and are still going.  How bad can it be?

[jaylw314]

On ‎5‎/‎10‎/‎2018 at 10:44 PM, xcrmckenna said:

Unlike most pilots I get scared hitting turbulence at cruise. It doesn’t take much turbulence before I’m slowing down to Va.

I was wondering what is a reasonable amount of turbulence or severity of turbulence it takes you guys to start slowing down in your Mooney? And if my concern is really valid.

This last weekend I flew down to KSAC. 40 minutes of the flight I was getting tossed around pretty good. And I missed the benefit of a nice tail wind. The sectional even indicates the area of extreme turbulence, on Sunday it was spot on.

What altitude were you flying at?  You can skip most of the fair-weather turbulence if you're up above 10,000 ft.  You can still cruise pretty good all the way up to 15-16,000 MSL in your J model.  Additionally, if you hit turbulence, the higher you fly the lower your IAS compared to TAS is, so you will be closer to Va upstairs.

[jetdriven]

7 hours ago, Jerry 5TJ said:

Those precise load charts are accurate — but is there anything special about 30 FPS?  I’ve seen those load charts drawn for 25, and 50 FPS gusts as well. Even 100 FPS is “only” 6,000 feet per minute & in convective processes that velocity is not uncommon, I read.  

Maneuvering speed seems, to me, to be a general cautionary warning based on a generic assumption of what gust velocity might be found. 

 

People get these confused al the time. Top of yellow arc is the speed at which the CAR3 airplane can run into a instantaneous sharp edged vertical gust of 30 FPS without damage. 

Va is the speed at which a pilot can make a single full control deflection and let go and not damage anything.  

Notice it is much lower than Vc, top of yellow arc. Just don’t get ham-fisted wirh the controls and stay out of the yellow arc in severe turbulence and your plane won’t break. 

Edited May 15, 2018 by jetdriven

[xcrmckenna]

What altitude were you flying at?  You can skip most of the fair-weather turbulence if you're up above 10,000 ft.  You can still cruise pretty good all the way up to 15-16,000 MSL in your J model.  Additionally, if you hit turbulence, the higher you fly the lower your IAS compared to TAS is, so you will be closer to Va upstairs.

When I started getting into the turbulence I was at 13,500 but was pushed down to 11,500msl due to clouds. That was only about 2,000 agl in that area though.

I would have climbed in to 15,500 but didn’t want to get caught on top. I promise I’ll get my Ir soon...


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[Hank]

The worst turbulence I've experienced was in clear air in western NC at 11,000 msl while headed home from SnF to WV. We bounced and shook for almost 30 minutes, passing just west of AVL. My buddy said it was the worst he's ever flown in, too. The winds were kind of strong from the west, I crossed Georgia at 4000', and climbed as high as my C was comfortable with two people and gear just before the SC line.

[carusoam]

Worst turbulence I have been in was the week before tornado n fun... Tampa had the same type of weather for a week...

The cold front ranged from TX to over the coast, off GA... no going around... changing quickly...

While flying slowly in IMC the iPad in the back seat hit the ceiling pretty hard...

The Strike detector was lighting up in all directions...

we didn't have ADSB weather at the time... that took another week...

 

We have reviewed...

• A reason to avoid going too fast in bumps...
• A reason to avoid going too fast when pulling hard on the controls...
• What to avoid when going around bumps... windy mountains, and thunderstorms...
• Two ideas regarding what parts of the yellow arc are important, for which mistake you are about to make...
• Nobody likes CATs... Clear air turbulance... you just can’t see any hint it is there...
• Two tools to have on board ADSB or XM weather, and a strike detector....
• when the strike detector is lit up in all directions... go slow, land soon....
• When you land, check the weather on line... the cold front probably ends less than 50miles off shore...
• Getting personalized weather advice is nearly impossible from the radio resources when so many people are flying in the neighborhood of the storm.... when the storm is crossing 1000 miles of the SE...

Best regards,

-a-

[RobertE]

To the original poster who referenced being chicken, all I can say is that I was planning a scenic flight that day in the Bay Area, saw and felt the wind, and stayed on the ground.  And I wasn’t flying over the mountains.  You’re not chicken. In fact you might actually be a BSD (check outMichael Lewis’ first book Liar’s Poker for the definition of that term).

[xcrmckenna]

To the original poster who referenced being chicken, all I can say is that I was planning a scenic flight that day in the Bay Area, saw and felt the wind, and stayed on the ground.  And I wasn’t flying over the mountains.  You’re not chicken. In fact you might actually be a BSD (check outMichael Lewis’ first book Liar’s Poker for the definition of that term).

Well my better half would have to defend that or say I don’t ..... I wanted to do the Bay tour before I flew north but it was really nasty down there. It was a great flight home except the eagle peak area.


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[Yetti]

I have 3 rules for flying

1. No Single engine piston in the CO Rocky Mtns.

2. Always land with an hour of fuel

3. Never fly through a front line.

While I was doing my primary training I saw this person depart the airport.     There was a front line between Houston and Dallas.    The end of the front line was to the south around Victoria.  If he did not want to wait it probably would have added an hour to the trip to fly around the end of the front.

http://www.kltv.com/story/20284250/preliminary-ntsb-report-on-east-texas-plane-crash?clienttype=printable

 

[jetdriven]

Not to mention the southernmost cell  in a line is usually always the absolute worst. Those of the ones the tornadoes come from. Those are the ones that are supercells  because they do not have to compete with moisture because there is not a storm on both sides of them. DL191 encountered the southernmost cell in a line.  Most airline crashes caused by wind shear or convective activity  were flirting with the southernmost cell. 

[xcrmckenna]

So a run down of what I’m reading. Please let me know if I’m wrong.

If I’m still in the green and not slamming the yoke controls to the stops trying to keep the plane dirty side down, pointy part forward I don’t need to be as concerned about doing damage to the plane?

Thanks for everyone’s comments so far.


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[gsxrpilot]

2 hours ago, xcrmckenna said:

If I’m still in the green and not slamming the yoke controls to the stops trying to keep the plane dirty side down, pointy part forward I don’t need to be as concerned about doing damage to the plane?

I'm of the belief that you'll be slowing the plane down because of personal discomfort (bouncing around in the cockpit) long before any damage will be done to the Mooney.

[320KPH]

The only inflight breakup of a Mooney I found online (searching a couple years ago) was due to tail flutter in a fast descent.

This would tend to indicate that the structure is not only incredibly strong, but can only fail by virtue of gross excursions from the POH...

(I was searching for this because a friend had had a LAME tell him that there was too much "play" in the ailerons and he wouldn't want to get caught out by flutter...)

[jetdriven]

shows how ignorant of aerodynamics the LAME was.  The ailerons can be disconnected and you can run the IAS up to north of 300 mph before flutter is a remote possibility 

[320KPH]

the vast majority of those individuals will thrust their hand firmly into your pocket and help themselves to your hard earned money unless you specifically tell them how it works... Perform unauthorised work and attempt to bill for it? No way no pay...

[jetdriven]

for many the airplane resembles an all you can eat buffet. They eat you pay. 

Edited May 17, 2018 by jetdriven

[RLCarter]

12 hours ago, Yetti said:

While I was doing my primary training I saw this person depart the airport.     There was a front line between Houston and Dallas.    The end of the front line was to the south around Victoria.  If he did not want to wait it probably would have added an hour to the trip to fly around the end of the front.

http://www.kltv.com/story/20284250/preliminary-ntsb-report-on-east-texas-plane-crash?clienttype=printable

 

I was flying back from Laredo the day before, it was severe clear and we could see the frontal line 100+ miles to the north, strangest looking weather I had ever seen, went east to west as far as we could see at 7500ft