Zoom reserve is airspeed, the ability to climb with pitch up only. It is safely used to climb just over the obstruction keeping some money (maneuvering airspeed) in our pocket, We have adequate energy, airspeed, either for climbing over or maneuvering around the obstruction. We are ripe with options. Zoom reserve is not meant for air show climb as fast as possible. The air show airplane has a big engine. We with normal engines certainly don't want to spend all our airspeed gaining almost enough altitude to recover from inadvertent stall. Nor do we want to pitch up early, forever giving up zoom reserve.

Short story, we want to takeoff fast and retain maneuvering airspeed until safely high.

We cruise with considerable zoom reserve. If we stabilize approach on final at 1.3 Vso until round out, we have quite a bit of OGE zoom reserve and even more in ground effect zoom reserve...zoom reserve that must be dissipated before we can safely touch down. Long runways make round our and hold off work safely to dissipate that zoom reserve some uncontrolled distance down the runway. Short field landing zones require that zoom reserve be dissipated way high and way out on final, or more safely in deceleration on short final, in order to touch down slowly and softly on the beginning of the LZ. The target touchdown airspeed is velocity of stall in low ground effect.

Short story, we want to land slow.

Well Jim, I can’t refute any of this. So, good with me...

I’ve been practicing my Ground effect takeoffs and after reading your trim recommendation in your book, now feel more comfortable going quite fast before I pull out to gain altitude. Thanks

Have bought your book for some of my retiring airline pilot friends. They (a couple) are used to flying the heavy metal for their entire careers.They also have a Cessna 310 and have bought an AirCam but these still based in the flatlands of FL. Your book should come in handy here in the not so little hills of WY.

Blue skies,

Tommy

TommyN,

While your 182 is a good mountain airplane, it is not the best trainer for on course thermalling and orographic lift using the valley ridge system up to the pass. Unless loaded or near ceiling, your good engine rate of climb masks gentle updrafts and downdrafts. That said, it can be done. Your cruise is slow enough that when you begin to identify updrafts and downdrafts prior to VSI needle change, you can quickly pitch up or down for efficiency in on course thermalling. Ridge lift will be hard to discriminate from your good engine rate of climb. When a change in direction of the valley ridge system will cause loss of ridge lift and below declination line downdraft, you can evaluate terrain to anticipate that and move to the other ridge in the ridge valley system.

If you can find an instructor with thermal and hydraulic experience and a low powered trainer, some dual would make sense. Otherwise, you will eventually pick up the more subtle natural energy effect in the 182. You still get full effect, but that effect is less percentage of total energy.

The other way to learn quickly in the 182 is to fly in significant wind on hot afternoons. Now natural energy will be a significant percentage of total energy.

Jim

High altitude orientation has us thinking in terms of the potential energy or potential zoom reserve of altitude. Altitude potential energy becomes kinetic energy (airspeed) when we lower the nose.

Low altitude orientation has us thinking in terms of the kinetic energy of airspeed, our zoom reserve. Until high enough to safely recover from an inadvertent stall, we rely on zoom reserve in the form of airspeed to maneuver safely in both normal air ground operations and in an emergency like engine failure.

Airport takeoff and traffic pattern require zoom reserve in the form of airspeed to be conducted safely. Air ground operations like crop dusting, pipeline patrol, air ground gunnery, or low altitude reconnaissance requires zoom reserve in the form of airspeed to be conducted safely.

Landing requires zoom reserve (1.3 Vso is fine) until deceleration to land with zero zoom reserve. Power pitch deceleration on short final using the optical apparent brisk walk rate of closure lessens the need for go around, but as zoom reserve is given up, zoom reserve in the form of airspeed needs to be replaced prior to pitching up in any go around. Deceleration at zero thrust after round out over the numbers makes go around not as safe after round out.

Jim,

Got everything except that last sentence.

“ Deceleration at zero thrust after round out over the numbers makes go around not as safe after round out. “

Are you talking about float and hope?

Best,

Tommy

I think he's saying that once you flare with the power at idle you've spent all your money

Yes, both. Apparent rate or any power pitch approach looks, feels, less safe at first, but so much control is soothing when we become comfortable with it. Throttle is a very important part and needs be used as the effective descent rate control it is during deceleration.

.

On 5th engine failure with a Pawnee that we couldn't figure out why it was heating, I got slow and turned it over in soft irrigated cotton rows. Had a bit more than six seconds which messed up my routine.

I ran across a good example of Jim’s teachings tonight.

Zoom reserve
Nose down falling no load turn
Wings level climb out

https://www.instagram.com/p/CGdD-fypwHt ... 4wiqj8iyo3

The slow turning 0-540 at 2500 rpm and 235 hp in that Pawnee (very identifiable by sound) wouldn't pull that load up that hill from a level with the field start. The zoom reserve, both from the dive and from ground effect in the field, got him up the hill. Nasty work. As soon as he could get a wing down without hitting trees, he turned while allowing the nose to go down. Coming down the hill on the next swath will be much easier.

However, I am not sure he is spraying trees. If that was the first pass, at maximum load, he may have got real busy and just didn't have time to shut off after the short level field. It is uncommon to spray field and trees with the same product. Sometimes with a hill next to a field, we have to race track one way only...down the hill and across the field.

Jim,

I went back to the Instagram post on my IPad and the translation only says "Banana Application"

Yes, a closer look indicates smaller plants until the tall trees on top of the hill. I think he is intentionally race tracking with up the hill applications. The right turn at the top is wrong for back and forth, but the higher hill left would prevent the correct lay off for a return swath to the right of the camera man. Tough application however one would go about it. If using ground flag men, rather than GPS, there is no way he could pick up the flag man in time coming over the hill toward the lower part of the field. The paved part in the bottom of the picture could be where the nurse rig is. In that case, many light loads would not be a hassle.

Anyway, like you said, good use of zoom reserve.

I was asked, in a PM, to define zoom in a post. Like Wolfgang, I interchange the terms a bit.

Zoom is the act or process of pitching up using airspeed to gain altitude giving Wolfgang basis for his famous statement, "airspeed is altitude." Zoom reserve is the kinetic energy state of enough airspeed to be able to gain altitude with a pitch up. Zoom reserve, to be fair, can also be the potential energy state of enough altitude to be able to gain airspeed with a pitch down giving Wolfgang basis for his famous statement, "altitude is airspeed."

Wolfgang in "Stick and Rudder" admirably tried to keep it simple with airspeed is altitude and altitude is airspeed, but most aerodynamic texts like Robert Reser's "How to Fly Airplanes" use physics terms. And Wolfgang refers to zoom and zoom reserve as well as "the law of the roller coaster." The man really understood what airplanes want to do. Wait! That is another of his concepts. In "Safe Maneuvering Flight Techniques" and posts here I have tried to use both "Stick and Rudder terms and "How to Fly Airplanes" terms.

The energy maneuverability that "John Boyd, the fighter pilot who changed the art of war" covered in his briefings and design of the best fighter airplane in the world is way more complex. While I admire his work, I do not have the physics background to fully appreciate it. And unfortunately, we can read little first hand of his work. He did briefings, long briefings, rather than write much. He was only interested in doing and had no use for being. We writers can easily get caught up in being rather than doing. Anyway, the yo yos that his kind of thinking brought into fighter tactics had to do with zoom reserve as well as tremendous power to weight ratio.

I think of "zoom reserve" as that airspeed above stall speed that could potentially be "converted" into altitude.

A "quick zoom" (rapid deceleration resulting from increasing the angle of attack by pulling on the stick or yoke) initially results in a rapid increase in lift (which translates into altitude). But it also comes at the expense of an equally rapid deceleration in airspeed (law of conservation of energy). It's not sustainable long term, obviously, because eventually airspeed would decrease below stall speed and the airplane would again begin to descend – rather rapidly.

A "slow zoom" is very useful if/when the engine fails, because you can trade off airspeed to "maintain altitude" for at least a little while. That allows you time to re-pitch for best glide speed, select a landing area, run through the emergency procedure, and perhaps even make a "Mayday" call on the radio...

We also take advantage of that "zoom reserve" on every landing, as we flare the plane to convert airspeed into additional lift to slow the rate of descent and cushion the landing. Done to perfection, our trade-off results in touchdown at minimal vertical descent rate just as the wing stalls – those seldom-experienced (at least by me) "chirp-chirp" landings... (And, as Contact often reminds us, that touchdown speed can be well below the published stall speed, due to "ground effect.")

If/when we manage to initiate a stall (or when "stall becomes imminent" per current FAA training directives), we are taught to do the opposite of a "zoom climb" to correct for the stall: we convert altitude back into airspeed by lowering the nose, re-establishing the wing's normal lift profile, and resuming normal flight...

As an Army helicopter instructor pilot, I used to tell our pilots that we were basically "energy managers" when piloting helicopters. Helicopter flight is all about managing lift, drag, gravity, airspeed, and torque – balancing all those using both hands and both feet on the controls. And it is largely a mental exercise which had to learned well enough to only occupy 10-15% of their brain power, so they could use the remaining 85-90% to handle their "real job," which was the combat mission assigned to them. Managing the helicopter's energy had to become a "background" task that didn't disrupt everything else... That was what separated Army Aviators from the "pilots" in civilian life.

But back on the topic of converting airspeed to altitude, or vice-versa: I used to explain autorotation technique (how a helicopter lands following an engine failure) as being the process of preserving as much of the energy the helicopter had acquired before the engine quit, for as long as possible until the helicopter was ready to land. After all, it is impossible to "add" any more energy to the system once the engine quits. (Once again, that pesky "law of conservation of energy" rears its head...)

But because high G-forces are what get people killed in "crash landings" we needed to burn off as much of that remaining energy as we safely could in the process of the helicopter arriving at the landing site and touching down safely. The odds of surviving a moderately slow landing with moderately slow vertical velocity are excellent, because of the low velocities involved. The G-forces would be much higher if you landed at closer to cruise speed, even if your vertical velocity was at zero (like crashing a car into a tree at 60 mph). The G-forces would also be much higher if you landed with zero airspeed, but with a very high descent rate (like jumping off a 3-story building).

Done absolutely perfectly, the landing after an autorotative descent would occur at zero forward airspeed and zero vertical rate of descent. In the "real world," that scenario rarely works out so perfectly. But every Army pilot with whom I ever flew (once they became familiar with the OH-58A) could consistently land at or below a brisk walking speed, with no more "vertical impact" than you would experience in stepping off a low stool. I always found it interesting how almost every pilot was smoother landing from an autorotation (even a "surprise" hovering autorotation) than they were able to land from a normal hover... It was just uncanny!

So, "airspeed into altitude" or "altitude into airspeed" are just different ways of expressing the law of conservation of energy. You can use one to buy the other, or vice-versa. It also helps explain why attitude controls airspeed, but attitude affects both airspeed and altitude... But that's a discussion for another day...

Good explanation of energy management Jim. I had a problem with autos in the TH-55 Mattel Messerschmitt. I kept trying to three point it onto the skids and tiny stinger. Ronnie Westmoreland asked if I was a tailwheel pilot. "Yes," I answered. Next auto he waited until I flared and yelled, "wheel landing goddam it." He was an artist.

Thanks for the zoom reserve explanation!! I now totally get why you use the term to encapsulate the concept. That explanation will save me one stumble when parsing Contacts much appreciated posts.

As JP256 pointed out above, zoom climb for altitude is not free. It is a tradeoff with airspeed. We must have good timing to be able to use the zoom climb effectively and not expect to stay up there. In the energy management turn, zoom provides a bit more vertical space and reduces airspeed for a faster rate of turn and thus decreased turn radius. The airplane doesn't want to zoom up very long. It wants to get back to trimmed airspeed. At the top of the wings level zoom, we lead rudder and apply aileron to start the turn portion of the energy management turn. Because of airspeed loss in the zoom, the nose wants to go down. All we have to do is release the back pressure. Because of the bank, the nose wants to go down. All we have to do is release the back pressure.

We are now pitching well down and vertical space available is becoming limited. We want to continue both rudder to keep the nose moving appropriate for the increasing bank and aileron to get more of the turn completed in the first half than in the last half of a course reversal. Of course we want to put the nose onto the target and this will determine the amount of rudder and angle of bank needed to get the nose onto target in the time left in altitude available. We are now gaining airspeed but this airspeed is not free. We are trading altitude rapidly for this increase in airspeed. Not needing so rapid a return to and certainly beyond trimmed airspeed, we may want to take some of the nose down out of the resultant pitch down. We don't want to pull back enough to load the wing. We don't do that until we have the nose on target and begin the pull up over the target. When we load the wing, we should be wings level.

Zoom and dive timing are integral parts of the energy management turn. While the target is the objective, we must live within horizontal and vertical space available, stall airspeed, and the airspeed we should never exceed. At any point we can level the wing and return to cruise pitch attitude.

Eloquently stated Jim! You just gotta go out and do it to really understand...
Best,
Tommy

Older Commercial pilots will remember the contact flying rather than instrument flying lazy eight. Even back then I didn't see the need to dive to Va to start the maneuver. I refer to maneuvering airspeed as enough airspeed to maneuver to miss stuff at low altitude without stalling the airplane. Different, I know from V speed proper definition. Anyway, this zoom reserve was used to make a climbing turn to near stall, allow the nose to go down naturally by releasing back pressure, and returning to Va.

The purpose of the lazy eight, prior to making it a basic instrument maneuver, was to get the feel for using airspeed to buy altitude and altitude to buy airspeed or energy management or zoom management. It was a good stick and rudder maneuver. Putting the various airspeed, altitude, and heading requirements into the maneuver took the stick and rudder feel out of the maneuver. It took the heart out of the maneuver.

The purpose of the energy management turn, gunnery return to target, or crop duster return to target is to turn around very quickly and most efficiently without stalling the airplane. The purpose of John Boyd's yo-yo was to get inside the enemy pilots OODA loop and cause him to become unglued. Whatever the purpose, it is a beautiful thing with great heart. It is worth a try even if it seem frivolous.