Good reminders. Its easy to see how someone could be caught off guard.

This is why I try to study how the air moves and behaves. Once you understand the basics, everything "clicks". You know why stalls happen, you know why spins happen, etc. You know what DA does to you, and how it affects performance of both the engine and the airframe. I want to WHY things happen, not just HOW to deal with them.

And of course, theres always more to learn about it.

I tend to think of the airspeed indicator, not so much as a "speed" indicator, but more of a "what the wing feels" indicator. For example, at high density altitude, it takes more actually airspeed to get the wing to "feel" the same lift as it would at low density altitudes.

Cary, that looks like a cool place. Well maintained, too. Do they still do the fly-in?

"Use the force Luke Skywalker."

ShadowAviator wrote:Good reminders. Its easy to see how someone could be caught off guard.

This is why I try to study how the air moves and behaves. Once you understand the basics, everything "clicks". You know why stalls happen, you know why spins happen, etc. You know what DA does to you, and how it affects performance of both the engine and the airframe. I want to WHY things happen, not just HOW to deal with them.

And of course, theres always more to learn about it.

I tend to think of the airspeed indicator, not so much as a "speed" indicator, but more of a "what the wing feels" indicator. For example, at high density altitude, it takes more actually airspeed to get the wing to "feel" the same lift as it would at low density altitudes.

Cary, that looks like a cool place. Well maintained, too. Do they still do the fly-in?

Couple of things:

While it takes more actual airspeed to get the wing to "feel" the same lift at high DAs, that does not mean more indicated airspeed. The indicated airspeed to use is the same as is used at lower DAs. A caution, though, and this not to pitch up as much as you'd do at a lower DA--it's way too easy to get behind the power curve so that the airplane won't climb. The better technique is to barely get off the ground, then accelerate in low ground effect (like less than 5' AGL) to something around Vy (not Vx, unless necessary to clear obstacles, remembering that Vx is a higher IAS at higher DAs), and then climb out at about Vy--and don't get impatient with the anemic climb rate. You can see this in my other poorly made video:



There hasn't been a fly-in to Marble for the last couple of years. I don't know if it's the current owners or that the fellow who used to put them together for the Colorado Pilots decided to stop. I know the caretakers, so sometime soon I'll give them a call and see what the current situation is. It is a truly beautiful place.

Cary

Cary wrote:
Couple of things:

While it takes more actual airspeed to get the wing to "feel" the same lift at high DAs, that does not mean more indicated airspeed. The indicated airspeed to use is the same as is used at lower DAs. A caution, though, and this not to pitch up as much as you'd do at a lower DA--it's way too easy to get behind the power curve so that the airplane won't climb. The better technique is to barely get off the ground, then accelerate in low ground effect (like less than 5' AGL) to something around Vy (not Vx, unless necessary to clear obstacles, remembering that Vx is a higher IAS at higher DAs), and then climb out at about Vy--and don't get impatient with the anemic climb rate. You can see this in my other poorly made video:


Cary

Yep. To clarify what I meant more, the ASI tells you what the wing "feels". So when it says 60 kts, then that means the wing feels like it is moving through the air at 60 kts. Your actual airspeed could be considerably more, though. (Basically what you said, I just explained it poorly earlier.)

Since you use the same indicated airspeeds for stall speed, Vy, Vx, etc. it helps keep things simple. Could you imagine if it didn't work that way? You would have to keep re-figuring your airspeeds throughout the flight!

I hear ya on keeping the nose down. I have noticed alot of pilots have a fear of flying close to the ground. They seem to think its going to reach up and grab them. Granted altitude is your friend, but so is airspeed.

I have done some safe, but very low altitude maneuvering with a CFI. Very enjoyable. Also, went up with the local crop duster in a Citabria and did some simulated crop dusting on our fields (we were bored and waiting for the turbulence to die down, so we could do aerobatics). Really helped get over the fear of flying low towards trees.

I watched your other video, and I definitely noticed the climb rate. That will take some getting used to.

That was a good opportunity: crop dusting and acrobatics in the same day. While somewhat similar control movement, many think they are the same. Maneuvering flight, including crop dusting, involves rapid control movement to the extent necessary to miss things. Acrobatics involves rapid control movement to the stop and is very dangerous down low.

Correction: Vx and Vy are not the same IAS at higher DAs! Vx is higher, and Vy is lower. At some altitude point, they match. I'm not smart enough to do the calculations, but thinking that they are the same as at lower elevations will get you into trouble.

Cary

Cary wrote:Correction: Vx and Vy are not the same IAS at higher DAs! Vx is higher, and Vy is lower. At some altitude point, they match. I'm not smart enough to do the calculations, but thinking that they are the same as at lower elevations will get you into trouble.

Cary

I knew you were gonna say that. lol

I forgot about that when I was typing that up.

I wasn't really focusing on the small (important, but small) changes of the V-speeds. The main point was about the relationship of the ASI and the wing.

However, that's a good point about the Vx and Vy. I hadn't really learned that until I started looking into mountain flying. If I remember correctly, Vx and Vy (IAS) meet at your absolute ceiling.

If you have the right charts I don't think the calculations are too difficult. You DO need the right charts which depending on your aircraft may be tricky to find.

The main equation in the mountains with a 172 is simple. At full power, leaned to max RPM, use only the pitch up attitude that will result in some climb. You will quickly find that little pitch up is available.

Energy management makes turns safer and provides zoom reserve in either altitude or airspeed.

Nature provides thermal updrafts to fly slow in and ridge lift.

In the lower DA of cool air, little energy management may be necessary. Later in the day in summer, it becomes critical.

Interestingly, the first time I learned about the various type of lift in the mountains (ridge lift, etc.) was on Microsoft Flight Simulator X. This was before I started flying.

It was a glider tutorial where you used thermals, ridge lift, and .... uh, another type of lift above ridge lift that I can't remember the name of.

You used these various types of lift to climb pretty high, then a rapid decent to land back at the airport.

Not a substitute for REAL training, but useful and informative nonetheless.

We instructors miss a lot when we fail to cross reference in every way possible.

High DA: Less engine thrust, less kinetic energy at same airspeed, equal potential gravity thrust of altitude, equal thermal energy.

Low DA: More engine thrust, more kinetic energy at same airspeed, equal potential gravity thrust of altitude, equal thermal energy.

High AGL:. Less hydraulic ridge lift.

Low AGL:. More hydraulic ridge lift.