NOTSO, I have mine set for 1.25-1.35 Vs (for each flap setting). Gives me a speed band about 5 knots wide. My IAS in the -4 is in MPH.
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Fast, On-Speed, Slow: A Common Language for Aircraft Control
- Thread starter Vac
- Start date
Dan, thanks for taking the time to read the paper and for the thoughtful comments. I think we're actually saying the same thing. The intent isn't to suggest that the on-speed condition guarantees positive excess power. Rather, on-speed defines the aerodynamic state of the wing, while available power determines whether that condition can be sustained. That's what Figure 4 was intended to illustrate—the same reference AOA can correspond to sustained flight, deceleration, descent, or some combination thereof depending on the available power. If that wasn't as clear as it could have been, I'll revisit the wording in the next revision. Thanks for pointing it out.
Cheers,
Vac
I always scare people on the passenger brief when we talk about emergency canopy opening, getting clear of the aircraft, safety belt operation…what it might be like if we can’t reach one of the three bailout field choices…
But when we are done, they always thank me for the commitment to safety, planning, briefing etc…
In 35 years of flying RV’s never yet had to use one of those fields, thus far…but still good to have that plan.
I wish I could say I understand your whole paper…but I’m afraid it’s gonna take a few re-reads and some study…it is fascinating that this whole other realm Exists and I know almost nothing about it…you guys understand things us mere mortals don’t contemplate.
Pretty awesome.
The ability to see this technology get implemented into a practical safety solution into GA aircraft , alone is well worth watching…thank you!!!
Not in lieu of ENTIRELY in ALL situations. We're not rotating, taking off, climbing out, and cruising using AOA - although you could if you had an AOA number to fly. As I said before, we used AOA Ref numbers in the Eagle for many phases of flight. But keep in mind that these basic AOA systems we're talking about in GA planes are not really set up to give you much info other than down at the bottom end approaching or at critical AOA. So when I and other say AOA replaces speed - we mean down at approach to stall regimes. Anything outside of that is airspeed. Essentially, once I make the base turn to final until the flare - AOA is king.
I didn't read his post as 120kts in the climb out on a normal takeoff (which I do for cooling as well), but rather he is going to pitch for 120 upon the motor quitting and look for a tree or fence to crash into. Maybe I read him wrong....
Yep, I've used it. Its pretty sweet.
No…I takeoff, accelerate to 120 to clear the trees usually with about 400ft clearance to the trees…about 3/4 of a mile off the end of our strip, which is surrounded by trees, wires etc…is a large open field…in an engine failure scenario right off the end of the strip which would require a 15 degree turn to the right…and then some form of abbreviated pattern…
The goal, would be to bleed airspeed from 120 mph ias over the trees and trade the energy available from the altitude to coast on down to the 80mph mark, then determine best course of action to attempt to fit in on the open, large farm field…
I have never actually shut the engine down, to see what the actual affects of the spinning, flat pitch blended airfoil Hartzell affords in terms of drag, but my gut feeling is….it’s a helluva lot of drag.
If this area is where AoA shines…then please educate me as to how so…the comment that you use it in lieu of airspeed boggles me…since Vacs video clearly shows an airspeed indicator, so I’m confused as to when to make the switch.
Steve
Fffflats
Well Known Member
Actually, with pressure diff and also APM but not vane or stagnation pt we can and I do, believe Vac does as well, takeoff on AOA. Climb out is better figured with AOA than speeds though with the jets you get compressibility and Mach so there is a transition… both Vspeeds Vx and Vy are impacted altitude as is AOA but AOA still compensates for all the other stuff so really speeds are only needed for the high end don’t rip your plane apart sort of stuff. AOA is better for best rate and best angle and with pressure diff for rotation.
Note twins have alternate concerns and generally need to watch speed.
Fffflats
Well Known Member
Yes, onspeed AOA as you’re predominantly doing the turn and aren’t really driving out straight anywhere
I'm enjoying the discussion and do truly appreciate everyone's thoughts.
RNB, it's been a pleasure watching your perspective evolve. Thank you
. High speed, asymmetric departures can cause airframe damage (ask me how I know that!) unless the airframe is built to be bullet-proof (e.g., GameBird or something similar). RV's have a 2 g limit with flaps deployed (not published, but Van designed to normal FAR23 requirements, so simply an assumption on my part). In this case, I'm pulling about 1.4 g's when I depart. None of us has a butt calibrated finely enough to tell the difference between 1.2 and 1.4 g's. And again--I really appreciate the conversation and the thought you've put into this!
We've spent a lot of time talking about AOA systems, displays, probes, calibration, audio cueing and even engine failure on takeoff (another pet project is doing the flight test for the TLAR app designed to help with pilot planning and decision making) . Those are all interesting topics, but they're implementation details. The paper is intentionally system agnostic. Its central premise is much simpler: would general aviation benefit from adopting a common operational language for aircraft control? Fast, On-Speed, and Slow are intended to describe the aerodynamic state of the wing, regardless of whether that information comes from airspeed, an AOA system, progressive audio, or some future technology.
v/r,
Vac
RNB, it's been a pleasure watching your perspective evolve. Thank you
Actually, I'd respectfully point out we are trying for a 3 wire every time we land--I always want to control my touchdown point with precision, and I like having perfect kinetic energy for touchdown. Do I always manage to achieve that? Nope. The AOA tone is just one more tool that helps me get there most of the time. As far as the asymmetric departure, you are absolutely correct that won't occur with a properly coordinated rudder. I start the demo at normal pattern speed and configuration (flaps 40), and the accelerated stall occurs at about 67 MIAS. I can certainly force the airplane to depart at 80+ knots indicated. I can depart controlled flight at any airspeed. I don't demonstrate that because I want the airplane to remain serviceable
. High speed, asymmetric departures can cause airframe damage (ask me how I know that!) unless the airframe is built to be bullet-proof (e.g., GameBird or something similar). RV's have a 2 g limit with flaps deployed (not published, but Van designed to normal FAR23 requirements, so simply an assumption on my part). In this case, I'm pulling about 1.4 g's when I depart. None of us has a butt calibrated finely enough to tell the difference between 1.2 and 1.4 g's. And again--I really appreciate the conversation and the thought you've put into this!We've spent a lot of time talking about AOA systems, displays, probes, calibration, audio cueing and even engine failure on takeoff (another pet project is doing the flight test for the TLAR app designed to help with pilot planning and decision making) . Those are all interesting topics, but they're implementation details. The paper is intentionally system agnostic. Its central premise is much simpler: would general aviation benefit from adopting a common operational language for aircraft control? Fast, On-Speed, and Slow are intended to describe the aerodynamic state of the wing, regardless of whether that information comes from airspeed, an AOA system, progressive audio, or some future technology.
v/r,
Vac
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Fffflats
Well Known Member
But for those without AOA do not read that as Vref. Ok in an RV but some platforms have a no flap Vref trap in that no flap Vref may be less than 1.3 Vs. Vref in lieu is not ok.
Fffflats
Well Known Member
Vac shows airspeed for comparison purposes; he also has videos with airspeed completely blanked out. There is a bit of combining Aero for Naval Aviators here with the Glider books. Min power required is an AOA not a speed and is synonymous with max glide time AOA, again an AOA not a speed, consider how you optimize your gliding turn most degrees of turn for least altitude lost.
Steve, I'm flying the same system as Vac has in his plane — I'm not a pro here but I'll venture an answer.
The OnSpeed system is audio-based (in addition to that display in the video), and the tones tell you where your are on the range from roughly Vy all the way to stall. If you engine dies on initial climb, you need to
- push the nose down, since your AoA's going to start climbing quick and you need to stop that from happening
- get into a 45 degree turn, so that you have a tight enough turn to get pointed back at the runway
- you'll be squeezed between your unexpected loss of power slowing you down, and the tight turn raising your stall speed...
So the familiar approach-speed reference sets a too-slow trap. If you fly the "OnSpeed" AoA (the solid tone), you can stay safely away from stall as you do this max-performance maneuver and your airspeed's all over the place.
The other nice thing about the wide range of AoA cueing is that you actually can fly AoA on rotation + takeoff. The tones start beeping at L/D max, which is ~roughly the same as Vy. And a solid tone ~roughly matches Vx.
So I fly the nosewheel off in my 10, hold the nose down until solid tone, then pitch for the start of the tone band. As the plane speeds up this has me increasing my pitch, and I can turn crosswind fairly aggressively for pattern work (with no one else around!), knowing that I am at constant AoA.
I glance at the airspeed as a "cross check" and it's nice to see that, yes, when I have less fuel on board, the speed's a bit lower than normal. Same thing on downwind — give a glance at the AoA to make sure the tones are roughly matching my airspeed expectation, then I don't really look at the panel again, other than a glance on final.
Anyway hopefully that's helpful, as some reflections from an AoA-newbie on how I really am flying tones + AoA.
Fffflats
Well Known Member
@justa6ereh @Vac
Examples of how not to do it are the best form of instruction. Behavioral economics, humans tend to avoid risk more than seek reward but we’re not good at appreciating or assessing risk. We learn to avoid bad much quicker and more readily with longer retention than how to do well. Further, often there is no best practice, rather many options of good practice, so teaching best practice becomes bad practice as such limits students and fails to allow them to adapt with context.
Examples of how not to do it are the best form of instruction. Behavioral economics, humans tend to avoid risk more than seek reward but we’re not good at appreciating or assessing risk. We learn to avoid bad much quicker and more readily with longer retention than how to do well. Further, often there is no best practice, rather many options of good practice, so teaching best practice becomes bad practice as such limits students and fails to allow them to adapt with context.
Ok, I read that wrong then, sorry.
One thing that occurs to me is your "emergency gameplan" seems like its only specifically tailored to your home strip. That's great if you never go anywhere else. And its also fine if you're always around farm fields with lots of open space. I always plan an "oh sh*t return gameplan to where I am currently - taking winds, off field environment (urban vs Rural) and any obstructions into account. For instance, if there are any crosswinds - all things being equal I would turn into the wind to minimize both my turn radius if I were trying to get back to the airfield and it reduces your GS for when you're going to land in a corn field somewhere.
I know of some people who shut down their engine to "test" actual glide. That literally gives me the Heebies just thinking about it. The one thing you can do to maximize your glide with a CS prop is to check and adjust if necessary your Static pitch stop settings. If its set wrong and the prop loses power and oil pressure - it could slam to a really fine/flat blade setting (unless you have an aerobatic prop) and act like a speed brake.
Sorry, but I digress. Not trying to get off topic here.
As before, I am a fan of AOA I. One form or another but again I will say that relying on one piece of info is an insidious trap that will be sprung when that piece of information, in this case, is not available.
This applies to really any of the available tools whether it is AOA, altitude callouts, or a HUD. It is exceptionally easy to get so reliant on one of these tools that when it is suddenly unavailable, pilots have forgotten how to use the other tools available, ie airspeed, vertical speed, etc.
At work, we call these guys HUD cripples; without the HUD, they appear to lose a substantial amount of flying skills…
Yep…guilty, I hardly ever go anywhere other than buzzing around like a dork. Tomorrow I’m running to the other side of the state and it always makes me study the day before…and really think through the good/great/bad/sucks scenarios before I go. So DEFINITELY a homebody. Probably on a ratio approaching 50:1 home vs. elsewhere’s.
The AoA discussion is very similar to our final glide computer in the sailplanes and I have used that for a long time.
Changing the way we think and challenging the instructional norms are very noble aspirations and I appreciate the willingness to field the questions, challenge the conceptual notions for utilization and honestly…put yourselves out there and defend your positions…
I think what you are doing is pretty awesome.
Steve
To this end…I gave a ride to a young guy with an instrument rating who jumped into my 6, settled in and upon noticing the lack of a gps device legitimately asked how we were going to find our way to Yakima from the Seattle area…
So…I’m sure there’s happy mediums with lots of this.
Ps…my new Garmin Aera 660 is amazing and simple. The magenta line is slightly addicting.
Steve
Yeah. I wouldn't fly around my Los Angeles area without a good GPS moving map, just for the airspace graphic if nothing else.
