We’re a fan of physicist Scott Manley’s spaceflight-focused YouTube channel. Now that he’s working on his private certificate he has discovered certain … umm … anomalies in the way instructors explain things. This includes the deadly blackhole of why wings generate lift. Even he punts on this one, referring to channels with aerodynamicists who don’t agree on an explanation, either. The poor man may be doomed to a tortured life as a pilot. One thing we didn’t know that he explained: those VORs with all the balls around the perimeter of the groundplane use FM for the phase signal and AM for the reference signal. Or is it the other way around? Watch the video to find out and if you’re an instructor, you’ll get an earful of what your students might be thinking.
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This guy reminded me of a Private Pilot student I once had who had a Master degree in Aeronautical Engineering. He unsurprisingly didn’t care for my over generalized 2 minute briefing on how a wing generates lifts. In fact he was quite offended at what he described as incompetency on my part, in that I could not correctly teach how a wing creates lift.
I said I would present a lecture that he would approve and that would become my new lecture after he could demonstrate the following during one flight
1) The ball was never more than half out of the cage
2) Cruise altitude was maintained plus or minus 40 feet
3) Airspeed on final was never more than plus 3 and minus zero.
I still give the same lecture on how a wing generates lift…..
Personally if I were going to make a lecture on what instructors get wrong, it would be how the aircraft systems work and how you know they are having a problem. The low water mark for me was when an Instructor candidate told me the function of the belt right behind the propeller was to turn the propeller.
Some of the questions I ask to see whether systems knowledge could use some work are (Cessna 172 examples)
1) What does it mean if the ammeter goes full scale right after the engine starts ?
2) How much should you lean the mixture on the ground ?
3) What does it mean if on a mag check there is no drop in RPM on one mag ?
4) When doing the mixture check what 2 things are you checking ?
5) What are you checking when you do the flight control check ?
I have a bunch more but sadly my experience is we are not even of the ground and many flight instructors can’t provide answers those questions and so if, they can’t you can be sure their students can’t either.
So you passed up an opportunity to improve your ground instruction by learning from someone obviously highly qualified in aerodynamics simply because he did not (yet) have the stick and rudder skills to meet your standards? Seems like a wasted opportunity to me.
He didn’t say he passed up any opportunity to learn anything.
Who’s to say it would “improve” his ground instruction? One of the most difficult things a CFI has to do is impart the many different levels of information (must know, should know, nice to know) to students without their eyes glazing over. Sometimes simple explanations work best (as long as they meet what’s in the Airplane Flying Handbook, Pilot’s Handbook of Aeronautical Knowledge, etc.)
These types of video/discussions are for rainy afternoons in the FBO or airport coffee shop.
In my experience, rainy afternoons are a chance to get in some real instrument flying.
I believe the point David was making is that knowing the precise technical reason how a wing generates lift doesn’t contribute in any meaninful way to actually piloting an aircraft.
What I tell my students about these type of complex subjects is that it would take a long time to go over all of the technical details, so instead I’ll give a simplified overview and focus on what we care about in flight.
Is this the same Scott Manley who is a CFIG and writes blog posts about Condor, the glider sim? Hmmm… To paraphrase what a CFI once said to me, “You’ve got your glider rating? All I can teach you guys is how to work the engine, fuel management, and how to climb with power without a towline.”
It’s not actually! Surprisingly there are 2 Scott Manley’s involved in online aviation.
Thanks! I did not watch the vid so I wasn’t able to recognize the image of the Scott Manley who posted the video from the tiny thumbnail in the link here. Years ago I took some dual from The Other Scott Manley. I didn’t watch the vid because I realized long ago that aircraft fly at any altitude by being supported on appropriately-sized piles of $$$$$.
Regarding the wing thing, Newton is always right. The force on a plane due to gravity near Earth’s surface can be summarized by F = mass[of the plane] x acceleration[from local gravity]. In flight at a constant vertical velocity (for level, it’s zero) there must be an opposing force of equal strength, F = mass x acceleration. Wings on airplanes accelerate, by deflection of airflow with a downwards component, a rather large mass of air a rather small amount to create this force. That’s it! Aerodynamics, if you will, is nothing more than learning how to do this efficiently. The force opposing gravity can also come from a small mass being accelerated a lot, like with a hovering SpaceX rocket, but that is not as efficient as the opposite.
+1
I once had a student and explained the difference between a carbureted engine and a fuel injected engine with great detail. After 45 minutes I asked him to explain the difference, and the answer was, “The carbureted engine has carburetor heat and the fuel enjected engine does not”.
KISS 🙂
My favorite comment from the video comments:
“The reason airfoils generate lift is because the full form of Navier-Stokes equations get so ugly that Earth pushes them away.”
Speaking of how things work and the math behind it, I always hated the whiz wheel.
“Well, you know the 10 actually means 100 and the 5 means 50 and the mark is almost, but not quite, next to the 2, which is 20”
Uhhhh nope. If I knew it was 100 and 50, I wouldn’t be needing to calculate it on a device. And “almost” on the 2? Is it “2” or isn’t it? It is unless it’s almost “20”.
No. Give me an electric E6-B. “But the batteries will die on you”. I’d rather know something and then have the batteries die than to never know something at all.
Tell you what, if the batteries die on my E6-B, I’ll ask ATC for vectors to the nearest airport, land, and figure it out on the ground.
The E-6B is just an aviation-specific slide rule. Once you realize you just move the decimal place left or right as necessary, it becomes pretty simple to use. Another way to think about it is that it gives you a “Fermi estimate” (or “order-of-magnitude estimate”).
As I tell my students, it’s better to get a “close enough” answer in flight than to spend so much time trying to get the exact answer that it no longer is relevant by the time you get it. And most times, even if you could instantly get an exact answer, your flying is never going to be precise enough that it would make much of a difference.
“ it becomes pretty simple to use.”
My comment is no reflection as to ease of use.
It’s the attempt to answer a question with a device that ask you to question. “Is that a 10 or, is that 100” for example.
As my instructor use to say, “you interpolate”. As most things involving aviation get down to the minutia, I found this odd.
I’ve never been happy with “close enough” when calculating fuel; remaining, burn or otherwise.
However, allow me to digress. When doing fuel burn/remaining/required with the electronic E6-B, I’m never surprised upon landing and indeed, it’s “close enough”. When using a whiz wheel, it’s never as satisfying close.
I’ve generally found the answers I get from the mechanical and digital E-6Bs to be very close to each other. Certainly less than the difference between calculated and reality.
You generally don’t think in terms of ‘is that a 10 or a 100’. You work the problem, get an answer with up to three digits of precision, and then apply the decimal point to where it would logically land.
If you can’t determine where that point is, than that means you can’t evaluate the reasonableness of your answer to even within an order of magnitude – not good.
If you fumble a bu
As a junior instructor I was tasked with teaching the navigation portion of the Private Pilot ground school. We had this 4 foot tall giant E6B on a stand which was an excellent training aid as you could work a problem with everybody able to see what you were doing. My helper was Joe the gorilla. For example if Joe ate 6 bananas in an hour how many bananas would he eat in an hour and a half. “Joe” helped to demystify what at first glance was an intimidating device.
I think that is the secret to good instruction. The point of the excise is not to show how smart you are, it is to give the students information they can use in a practical way to make them better safer pilots. AFAIK, no private pilot ever died because they couldn’t provide a description of how a wing lifts to a level that would satisfy Mr Manley.
For those who haven’t been regularly watching Scott Manley’s videos, you might not have the context to know that he made that video mostly in good fun, and not to disparage flight instructors. And he doesn’t say anywhere in the video that a full understanding of how a wing generates lift is necesary for piloting an aircraft. He’s a bit of a science geek (in the good sense), so he likes to go into technical trivia just for the fun of it.
Though I do feel that we instructors should not be using the “equal transit time theory” to explain lift, because it is scientifically invalid and there are better simplified answers to explain why the pressure on top of the wing is lower than the pressure below the wing.
I call Mr. Manley and raise with this brilliant description:
http://messybeast.com/dragonqueen/liftdemon.htm