Plane down at Dayton Airshow

[pullup]

Saying...."if this, this, that, that as well, AND that happened, then that person is stupid" isn't useful. It is degrading and unnecessary for those lost.

Agreed, calling a pilot stupid or otherwise insulting him is just, well, stupid. Speculating on what may have happened is not. Pilot error can absolutely be talked about without slamming a pilot also, it's something that happens quite frequently.

 

[MikeD]

(Next part is not directed at you Seggy, but the general group) Pilots usually want to fix things, that's what comes with the job. If there's a problem, fix it. Because of that, when an accident is captured on video, the wheels in the head start turning as to what may have been the issue. It's just natural and those thoughts are put into text via this forum to get others opinions and help to understand the bigger picture of what may have went wrong (learning). Stating an opinion as fact on an accident is not the proper way to discuss the incident, but I think most of the time it is done sub-consciously and people don't take the time to proof before they hit the submit button.

This is exactly why I wrote earlier that often, pilots make some of the absolute worst accident witnesses for me to have to interview.

 

[rframe]

Little work by the NTSB. Those low profile accidents with no injuries or minor, are actually normally handed off to the servicing FSDO by the NTSB, for a single FAA investigator it handle.

The examples he was giving me included fatalities and it boiled down to neither the NTSB nor the FAA had resources, so it was essentially "you have X days, write the report". He is currently involved in the efforts to look at supplementing with volunteers, I last talked to him about 4 months ago, I'll have to see what updates there are.

 

[MikeD]

The examples he was giving me included fatalities and it boiled down to neither the NTSB nor the FAA had resources, so it was essentially "you have X days, write the report". He is currently involved in the efforts to look at supplementing with volunteers, I last talked to him about 4 months ago, I'll have to see what updates there are.

The NTSB may have started delegating more too. Budget hitting everyone.

 

[Stomp16]

This is exactly why I wrote earlier that often, pilots make some of the absolute worst accident witnesses for me to have to interview.

I can see where that would be a problem. But are you then implying that since pilots make bad witnesses that discussion should not take place concerning accidents?

 

[MikeD]

I can see where that would be a problem. But are you then implying that since pilots make bad witnesses that discussion should not take place concerning accidents?

*Banghead*

Ive made my position clear on more than one post here in this thread. Go back and read....just even a couple of pages.

 

[Stomp16]

*Banghead*

Ive made my position clear on more than one post here in this thread. Go back and read....just even a couple of pages.

I've read this thread numerous times. I just want to be sure that I understood completely the point behind what you last wrote. No need to "banghead".

 

[MikeD]

I've read this thread numerous times. I just want to be sure that I understood completely the point behind what you last wrote. No need to "banghead".

One has nothing to do with the other. They're separate and distinct ideas here in the thread (as well as in reality). Was only addressing what you wrote.

 

[Roger Roger]

I appreciate the insight of those folks in this thread who have experience flying upside down and flying biplanes. Good insight to know some of the issues involved that I wouldn't have thought of.

 

[Stomp16]

One has nothing to do with the other. They're separate and distinct ideas here in the thread (as well as in reality). Was only addressing what you wrote.

I figured that's what you were getting at (separate and distinct) but was just making sure and that's why I asked what I did.

 

[MikeD]

I figured that's what you were getting at (separate and distinct) but was just making sure and that's why I asked what I did.

Thats all good.

This whole thread still makes my head hurt

 

[stormchaser]

I've read all the posts.

As a a pilot who has never been upside down before (I know, I know, I just lost some love from 36 of you)... ... how exactly does a stall work in this situation? I kind of feel a bit stupid for asking the question, but I'll give up pride any day. If I am straight-and-level, and I stall in normal flight, I fall to the earth (simple terms). Now if I dive straight down towards the earth and pull back past the critical angle of attack, I actually find myself diving at the earth again in a stall. I get that.

So my curious and innocent question is...with an airplane upside down, is the "lift" going towards the earth or away? And is the majority of lift then created by the wing or by the elevator?

I'm ignorant of bi-planes and the wingfoil. Is it symmetrical?

Here at my table I've done the "piece of paper flying," completely inverting it, turning my head, etc., to try to understand it, but I'm just a bit in the fog still. I guess what I am asking is...in the most simple of explanations, when an airplane is flying upside down and stalls, does it momentarily pitch up (from someone standing on the ground) due to the airflow separation and then fall down with gravity, or does gravity just grab that whole bird and drag her down once the critical angle of attack is hit?

I'll be the first to admit ignorance and take one for the team on this one.

Simplicity is appreciated. ha! Even I don't believe I'll see that!

 

[Stone Cold]

The wing does not care if it is upside down, symmetrical, or anything else. A wing will stall right side up or upside down in the same way. The 4 forces are also still at play. Gravity is the one that kills, lift keeps you up. Whether the pilot is hanging on inside, or departed the aircraft, the wing does not care.

Is that simple enough? You don't have to turn the picture upside down, it is still an airfoil with lift opposing gravity...

 

[stormchaser]

The wing does not care if it is upside down, symmetrical, or anything else. A wing will stall right side up or upside down in the same way. The 4 forces are also still at play. Gravity is the one that kills, lift keeps you up. Whether the pilot is hanging on inside, or departed the aircraft, the wing does not care.

Is that simple enough? You don't have to turn the picture upside down, it is still an airfoil with lift opposing gravity...

Yeah, I like simple. Thanks. I'm just familiar with the outrageously "kind" wings that have much higher upper cambers than lower cambers and didn't know if Stearmans or other aerobatics airplanes had upper/lower cambers that were much more similar to each other.

 

[fholbert]

I can't help but notice that they appear quite a bit higher and faster in this performance than in the accident video.

Don't say that. The forum police will have to correct you!

 

[derg]

Don't say that. The forum police will have to correct you!

Police? Shoot, bro. I'm legislator, enforcer, judicial and executioner!

 

[smack300]

Well hopefully after 8 pages we all know how to talk about the accident.

That said, I find it interesting that the pilot rolls to the right in the accident but in the other video, the pilot rolls to the left. I'm sure someone here more advanced in aeronautics can explain it better than I but it seems rolling to the left would be easier and require less rudder than going to the right. Rolling to the left would cause her to be on the on top of the airplane when it is at a 90 degree angle. Wouldn't that parasite drag pull back the left wing therefore causing the nose to be a couple of degrees up and allowing for a climb during the turn?

Hope that makes sense, like I said someone else can probably visually explain it better than I.

And here is the other video that TwoTwoLeft posted. Go to the 11:00 mark

 

[dustoff17]

Well hopefully after 8 pages we all know how to talk about the accident.

That said, I find it interesting that the pilot rolls to the right in the accident but in the other video, the pilot rolls to the left. I'm sure someone here more advanced in aeronautics can explain it better than I but it seems rolling to the left would be easier and require less rudder than going to the right. Rolling to the left would cause her to be on the on top of the airplane when it is at a 90 degree angle. Wouldn't that parasite drag pull back the left wing therefore causing the nose to be a couple of degrees up and allowing for a climb during the turn?

Hope that makes sense, like I said someone else can probably visually explain it better than I.

And here is the other video that TwoTwoLeft posted. Go to the 11:00 mark

Interesting obeservation, I hadn't noticed that. After your post, I searched a lot of video from past shows, each time the pilot rolled left...........

. Here's a different angle:

 

[TwoTwoLeft]

Well hopefully after 8 pages we all know how to talk about the accident.

That said, I find it interesting that the pilot rolls to the right in the accident but in the other video, the pilot rolls to the left. I'm sure someone here more advanced in aeronautics can explain it better than I but it seems rolling to the left would be easier and require less rudder than going to the right. Rolling to the left would cause her to be on the on top of the airplane when it is at a 90 degree angle. Wouldn't that parasite drag pull back the left wing therefore causing the nose to be a couple of degrees up and allowing for a climb during the turn?

Hope that makes sense, like I said someone else can probably visually explain it better than I.

And here is the other video that TwoTwoLeft posted. Go to the 11:00 mark

The pilot rolls to the left in both acts.

In the show from 2011, the pilot has quite a bit more energy going in and pitches up significantly more before starting the roll. In the crash video, when he hits the 135* point in the roll you can actually see the altitude thats been lost and the pilot trying to recover.

The pitching up prior to the roll sets the attitude and prevents altitude loss. There are aileron rolls and slow rolls. With an aileron roll, the airplane's CG just follows a ballistic path (think Bob Hoover pouring the ice tea). The nose will actually trace a capital "D" on the horizon. With the slow roll (not related to the actual roll rate) the airplane's CG must follow a horizontal plane. To prevent altitude loss in a slow roll, the pilot must use appropriately timed rudder, forward stick pressure and rudder and relieve stick pressure throughout the roll. The slow roll does not feel as smooth and you would not want to be pouring anything. The nose will trace a circle, with the bottom resting on the horizon.

In slow(rate) rolling airplanes like Stearman, for airshows, pilots tend to use a combination of the two. It makes energy management easier and shows nice. This particular Stearman appeared to have 4 ailerons. So it's roll rate was much better then the convention 2 aileron setup.

The roll in the 2011 show was more characteristic of an aileron roll, while the roll in the crash video appeared to start off more like a slow roll.

The most common error with the slow roll in an airplane like a Decathlon, Great Lakes, or Stearman is the start of the roll. How well the roll will turn out (heading and altitude) is all based in the first 1/4 of the roll. You use a combination of adverse yaw, "top" rudder with some push to set the attitude so you don't have to over push through the inverted portion or jab the rudder through knifedge. Over controlling will cause extra drag and will lead to energy loss. Having the walker out by the N strut can create some adverse yaw, but against the direction needed to start the slow roll.

In an airplane like a Pitts variant, or high performance mono plane all you do is apply aileron and think about rudder and you've rolled.

 

[🦈💜]

So my curious and innocent question is...with an airplane upside down, is the "lift" going towards the earth or away? And is the majority of lift then created by the wing or by the elevator?

Wait, you're a pi... aw, just kidding.

Bear with me for a little stupid thought-experiment here:
Assume we have an atmosphere but no gravity. If you take a baseball and release it at eye level it will stay there. If you push it, it will move forward for a bit, but eventually stop. We're in a giant box, fifty miles to a side.

The amount of lift you need to produce to stay aloft is... well, zero. But if you point your nose at a target straight across the box, you'd be generating lift as you pass through the air, so you would be gaining altitude as you went along. Why are y0u gaining altitude? You're producing lift. Why are you producing lift? Because the design of the airfoil (most airfoils) and/or the angle the airfoil is mounted to the aircraft result in a positive angle of attack or accelerate airflow sufficient to produce some lift. To stop this altitude gain, you could either stop moving forward through the air, or you could decrease the angle of attack through zero until you found a point where you no longer gained altitude flying straight ahead. That angle of attack is the attitude you could fly to get from one side of the box to the other. Less than that, and you 'lose' altitude. More than that, you gain altitude. Accelerate, and you produce more lift for a given angle of attack; decelerate, and you produce less.

To fly a 'straight course' to the other side of the box, you want zero lift... but you can think of that as 'zero pounds' of lift.

But hey, since we're in a giant box, fifty miles to a side, why not just point straight down and find that point again where we're no longer going up or down? The attitude in which we produce zero pounds of lift? And then push the nose forward to go back the way we came?

And why straight sideways, straight up, or straight down? If we "decrease" our angle of attack, we will go "downward" relative to our aircraft. If we increase it, we will go "upward", again, relative to our aircraft. It doesn't matter. You could have runways facing any direction and land on them as easy as you please.

Now the -only- confounding factor that we have on this planet that makes it different from that little experiment is gravity. If you're flying upright and you weigh 2240lbs, you need to be producing 2240lbs of lift to not descend.
Now, take the same airplane and flip it over. How much lift do you need to produce to stay aloft? at least 2240lbs. That's all gravity does for you that changes anything.

Symmetrical or asymmetrical airfoil, doesn't matter. An asymmetrical airfoil will be less efficient generating 'negative lift', because its shape produces some lift by itself independent of AoA, but effectively you change the amount of lift produced by changing speed and AoA. A symmetrical wing is producing zero pounds of lift at 0° AoA.

Flip the plane over, and what do you have to do to maintain level flight? You have to increase angle of attack... in a negative direction. By pushing forward on the stick.

So what if you need to produce more lift? What if you slow down? What happens to lift? 2240lbs to remain aloft, but your speed is decreasing, so you have to ____________ your angle of attack by pushing __________ on the stick?

And what happens when you exceed your critical angle of attack?

Going back to my gravity-less box, what happens when you stall there? What's the only dfference between 'there' and 'the real world'?

I guess what I am asking is...in the most simple of explanations, when an airplane is flying upside down and stalls, does it momentarily pitch up (from someone standing on the ground) due to the airflow separation and then fall down with gravity, or does gravity just grab that whole bird and drag her down once the critical angle of attack is hit?

I hope my stupid, long-winded thing has helped, and that you've been able to answer that question for yourself at this point. But if not: If you stall inverted, the nose drops. Towards the earth. Because of gravity. Because you've exceeded the critical angle of attack pushing forward on the stick.

Hopefully that wasn't condescending, too simple, too complicated, too short or too long... but I'm sure it managed to be all of those. I'll have to work out a better explanation.

~Fox