Flying the Rotor
 

Reading some of Birdy's posts, it appears that when he is flying he focuses his attention completely outside of the cockpit ("cockpit" being a figure of speech for his feral gyroplane). He simply decides what attitude and location he wants the gyroplane, and then he gives it whatever control is necessary to make it assume that desire. He alludes to the fact that the rotor tells him (through the feel of the control stick) everything he wants to know about the progress of his flight, and he answers the rotor accordinging by changing control inputs. Flying like this, the gyroplane has become an extension of his body and mind (they're at one together), which allows him to safely do whatever he wants with the aircraft. The end result is a very fluid, dynamic and aggressive method of flight which we all admire.

As a FW pilot I was taught to "fly the wing" (AOA), controlling the aircraft while keeping my head out of the cockpit. Have they written anything about "Flying the Rotor" (AOA) for gyroplanes? There are numerous things that can happen to a rotor in flight. Schooling in flying the rotor would teach us what those things feel like through the controls as we're approaching them; and what control inputs do you use to prevent them from progressing?

I couldn't find a topic like this in the flying archives. I suspect some of the flight instructors can address this.

Thank you.

Dave

I have found that pilots who learn to fly an underpowered gyro are better at flying the rotors than a pilot who starts out with tons of power. Having excess power to get you out of a jam becomes a crutch at first and ultimately a barrier to good piloting skills developing. But that's just my opinion. Also if I were to write the book on gyro flying I would caution people to never install a rotor gauge....what information can they possibly provide a tuned in pilot that he doesn't already know? And if you need one to take off, you should get a refund from your CFI!

Never thought of it that way, but when your tuned into your aircraft, you can hear and feel most any little changes around you.

A useful flight instrument for me.
 

Hello Ben,

I find value in the rotor tachometer during takeoff.

I tend to hurry the blades and the rotor tachometer keeps me in check and helps my consistency.

When I fly unusual maneuvers the rotor tachometer helps me to quantify how close to trouble I am.

The rotor speed bleeds off quickly when I decrease the load on the rotor. I avoid maneuvers in the Predator where the rotor speed drops below 270 rotor RPM (she flies at 315 RRPM solo with a light fuel load).

I also avoid maneuvers where I exceed around 440 rotor rpm because I feel this is an indication I am putting too much load on things.

Mariah Gale’s panel will have a 3.125 inch analog tachometer with clearly marked red, yellow and green areas so I can get a better feel for it than my digital tachometer gives me for approaching trouble.

I consider it a useful flight instrument.

Thank you, Vance

The Bensen manual hammered on this notion -- "fly the rotor, not the airframe" was Igor's motto.

It's certainly true that knowing how the rotor is feeling at any given moment is key to flying well. Whether it's lightly or heavily loaded can be felt through stick pressure feedback. So can RRPM and even airspeed. These informative pressures are a function of the offset gimbal head and trim spring arrangement that most of us use; control feedback is less informative with a swashplate version of cyclic control.

When Bensen said "fly the rotor," however, he meant something more. He meant ignore the stance and rotation of the frame because the frame follows the rotor at a lagged pace, if at all.

This notion is certainly true of wingless gyros in the roll axis. It should NOT be taken as a good, or inevitable, thing in the pitch axis, however.

Proper horizontal tail surfaces, and avoidiance of thrustline-CG offsets, can make the frame follow the rotor quite quickly and reliably. You still need to be conscious of the information provided by stick feedback, but it should not be necessary to "float" the stick to intentionally de-couple the frame and the rotor. The need to "float" the controls is evidence of an unstable airframe.

I'm developing a basic flight display android app, and having green/yellow/red indicators on the rotor tach is a great idea! Thanks a ton, Vance!

At the Risk of getting Off Topic.
 

Your welcome Ronnie,

At the risk of getting off topic that is why I like analog instruments.

I can identify trends better and the colors make my instrument sweep faster for me.

All of the engine instruments in The Predator are marked with red, yellow and green.

Part of what I do regularly is say out loud temperatures and pressures in the green as I finish the scan.

Part of the take off procedure is to say out loud temperatures and pressures in the green before I validate the takeoff and depart from runway heading.

If I see an engine instrument moving into the yellow I can watch it more carefully and work to mitigate the challenge.

I don’t have that functionality on my digital engine tachometer or digital rotor tachometer. I am sometimes surprised by the readings.

I found it challenging to correlate the digital ground speed with the analog air speed while sporting around in the air show.

I do not have a specific reason for my rotor RPM limitations, I just don’t like the way she feels outside my limits and I quantify my “feelings” with the rotor tachometer.

I don’t like to make emotional decisions while flying; I would rather access my emotions in the post flight debriefing and then adjust my limitations based on the recent experience.

Thank you, Vance

Vance: Amen to your comment about analog vs. digital.

An analog instrument, simply and objectively, supplies more information than a digital one. It reports rates and trends as well as the present number. The same amount of data would require two additional displays (three in all) to be reported by a digital readout.

[How many old Vermonters does it take to change a lightbulb? Three. One to screw in the new one and the other two to tell you how much better the old one was...]

Careful here Ben...

I agree that you need to know how to tell when your rotors are going fast enough to start your takeoff roll, and that it is pretty easy to tell in an open frame smaller gyro, but some of the gyros out there now need more than what it required for a small gyro... IIRC the Xenon needs 250 RPM. You can't see that RPM by feel and sight... you have to have a rotor tach for that.

That's why the 1970s fad for digital watches faded away, and analog displays came back into vogue. It's faster and more natural to recognize how long it is until noon if you look at clock hands showing 11:37 than at digits showing 11:37.

I have found some other odd psychological results from the form of display of the information. After hundreds of hours of flying old no-governor Robinsons with twin facing needles for rotor and engine rpm, with max values at the top and min values at the bottom following an essentially linear vertical path, I was used to that display. In a Robbie, needles going up means increasing rpm. Then I got into a helicopter with clock-like hands on the engine-rotor tach and with the max values at the 3 o'clock position. Near 100% flight rpm in that ship, the clockwise turning needles actually go down (toward 4 o'clock) for an increase in rpm. My immediate reactions were backwards (to correct in the wrong direction) because I had spent so long with the other display. It didn't take long to sort it out, but it was awkward for a bit, and I am now very careful with students who transition from one gauge style to the other, and who might react to the direction of the needle rather than the value to which it points.

For the J-2 and the 18A, with spin-up to 125 - 150% of flight rpm before brake release, a rotor tach is essential. The enclosed cabins also reduce airspeed sensation, and stick feedback is limited with their fully articulated rotors. The J-2 was not a spectacular climber, and I put a VSI in mine to help me optimize climb rates. It's important to be able to land safely if any instrument fails, but for some aircraft, precise operation is enhanced by having some data available beyond what the seat of your pants tells you.

I figured that line would stir up some comments!:)
I only fly lightweight open frame gyros, and to ME...myself and I only!!!!....I really wouldn't want a two seat enclosed gyro, better off to get a small fixed wing for A to B travel..If you NEED a rotor tach to tell you whats happening outside, well that's just not flying in my book!
So you CFI's can ethically keep your pay, I guess the rotor tach has its place, just not for me and the type of flying I do.
And Vance my brother, if you are going to chase my tail at El Mirage this year please don't be looking at your rotor tach, rather keep your eyes pinned on my backside! (you know California and all)
Thanks guys

Hopefully I don't step on any toes with my next statement, though I likely will, lol.

Must be because I'm a lot younger than most of you. Since the majority of my life has been spent with console and computer games, I pretty naturally convert data to the reference it calls for.

Good post Doug. I believe Davids feral is clt or ltl thinking back on old posts. I commented before on how his disc loading is lower than mine. I would find it hard to believe that he would have to make conscious stick movements "or lack of" in strong aussie thermals. I could be wrong though. :-)

No tender toes here. We can all deal with data; that's not the issue. But if you're suggesting that a few thousand misspent hours of Call of Duty and Assassin's Creed makes you able to compute trend and rate from a single digital display of a changing value as fast and efficiently as you could discern it with an analog display of the same information, I'll simply choose not to believe you, and to believe what the behavioral research shows instead. It's a human factors design issue, not a generational difference. Doddering old fart or feckless newbie, we're all better at picking up more information faster from an analog presentation. That's why modern glass panel displays include a vertical "tape" on the sides instead of just a single number for airspeed or altitude. The tape provides the analog benefit that you wouldn't get if the panel displayed the bare number alone.