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Stall/Spin or Low Speed Spiral, turning Base to Final

Ed_Wischmeyer

Well Known Member
So I re-read the posting rules, and I think this is legit...

On Wednesday night, I was the presenter at the monthly NAFI (National Association of Flight Instructors) MentorLIVE webcast, presenting on the information in the title and how to easily prevent both of those. The presentation included *five* videos shot in the RV-9A, although three were altered to make it look like they were flown at dangerously low altitude at Oshkosh.

Enjoy: https://www.mentorlive.site/program/60.html

(Not because of my name recognition, but it has already passed 3,000 views. Trying to keep RVs and everybody else out of the NTSB reports...)
 
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Does anyone have problem viewing this using the Google Chrome browser? I entered my info but the side bar didn't show up. This problem is on PC Window and on the Samsung phone.

Using Firefox browser works okay.
 
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So I re-read the posting rules, and I think this is legit...

On Wednesday night, I was the presenter at the monthly NAFI (National Association of Flight Instructors) MentorLIVE webcast, presenting on the information in the title and how to easily present both of those. The presentation included *five* videos shot in the RV-9A, although three were altered to make it look like they were flown at dangerously low altitude at Oshkosh.

Enjoy: https://www.mentorlive.site/program/60.html

(Not because of my name recognition, but it has already passed 3,000 views. Trying to keep RVs and everybody else out of the NTSB reports...)

You must mean "prevent"...... right?...;)
 
Too many requirements for me.....

info.JPG

Is there a simple way to view??
I will "circle back" later.
.
 
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Thanks for sharing your presentation. I've salvaged more than my fair share of botched approaches and the presentation gives focus to what can go wrong. I tend to focus my attention over the nose and wait for the runway to come into view with the control inputs I am comfortable with. When I complete the base to final turn then I decide if I can fix the overshoot or excess height.

I create my challenge from wanting to fly a pattern that always gives me the opportunity to land on the runway if the engine quit. Sometimes others in the pattern will dictate I fly a wider, longer pattern than my usual. Maybe the short answer is "Don't do that" and fly a wider pattern that affords more time to sort out the details.
 
That’s a good presentation Ed. I like to keep things simple, and the way you did it in gliders is an excellent method for doing that. Most of us flying RV’s are very comfortable with steep bank angles (at altitude), and we may be more prone to making it too steep while in the pattern. Giving yourself a basic requirement to not exceed 30* on the base to final turn should protect against getting close to a low speed spiral. And if that results in an overshoot, no big deal, fly the airplane.
 
The form won't "Submit" for me either on Chrome.

For those who don't want to give their info, give fake data.
 
Didnt watch the video because I dont click on external links, but heres a question that has bugged me for a long time:

As a CFII, how does teaching an admitedly very conservative pattern behavior to new students flying very conservative airplanes compare to the military instruction of "max performing the wing"? It seems that the idea to ride the edge of stall all the way to landing on something vicious like a T-38 coming off the perch is very, very different approach - yet it is the military way, proven for decades.

True, different training, but does that mean that one way is always better for RV's? Or is this a "lowest common denominator pilot" issue?
 
"As a CFII, how does teaching an admitedly very conservative pattern behavior to new students flying very conservative airplanes compare to the military instruction of "max performing the wing"? It seems that the idea to ride the edge of stall all the way to landing on something vicious like a T-38 coming off the perch is very, very different approach - yet it is the military way, proven for decades.

True, different training, but does that mean that one way is always better for RV's? Or is this a "lowest common denominator pilot" issue?"

Michael

Trying to compare standard civilian training to a military syllabus is difficult at best. Not apples to apples for sure. From the start, military training will emphasize and spend untold amounts of time on theory of flight performance, focusing on high performance aircraft. Every student is expecting to fly something high performance someday, so they soak that up. Then when they get to the plane (or sim) they'll practice multiple edge of the envelope maneuvers on each flight, practicing what they know until it's second nature.

It's probably hard to get a "Sunday flyer" kind of student (no offense intended) to get that depth and pace of training when they're paying the bill and fitting it into their life schedule.

I do feel that more CFI's should push the envelope a little more, but the instructor needs to be comfortable doing that. Their job is to get their charge to solo without killing anyone, so they do that, and pretty well. And for some reason, no one expects a student pilot to spend time at the edge (done safely of course). If your CFI isn't comfortable doing stalls/spins/steep turns, the student certainly won't be. Check in the box and move on only emphasizes the un-importance of the maneuver.

As a quick example, a USN student in the Strike pipeline will make their first aircraft carrier landing with likely less than 150 flight total flight hours (about 80 in the jet they land on the boat) and a gob of sim time. By that time they are instrument qualified in two aircraft. They're still "new" but have significant skills and are very comfortable doing things most civilian pilots have never dreamed of doing. That's just their assignment.

I might say that the difference lies in the goals of the student. If they plan to stay a "Sunday pilot", then the current plan seems to mostly suffice. If they're hoping to do some exploring of the edge in their RV, then maybe a different approach is in order.
 
Stalls

65 years of unstable approaches just as I learned in the Cub. Ag pilots take this to a whole new level. How come we're not all dead?? Its all about angle of attack.
Watch the RV4 turnback video. All done on angle of attack, airspeed is not a part of the occasion except to say that too much speed compromises the turnback.
 
Thanks for the response Bill. I consider myself fortunate to have a large number of military aviators as flying buddies, and your answer is in alignment with theirs.

Totally agree that some pilots have no intent or interest to find the edges and there is nothing wrong with that as long as they are aware that there is some risk of doing the "wrong" thing when that rare edge case presents itself. In these cases, some rote guidance like "never exceed xx degrees of bank when in the pattern..." makes sense.

The flip side of that of course is when you have a pilot who IS trained, proficient, and comfortable with the "...max perform the wing..." approach, and performs the landing as such. Should THIS pilot be taken to task for doing it in the civilian environment? Does this community endorse this display or condemn it as "hot dogging" or "reckless"?

There are many different skillsets among us and plenty of different "displays" of flying skill - and often not in alignment. We need to be careful not to paint all pilots with the same brush in these discussions.

And for the record, I'm not suggesting that this particular thread or the OP is going down the "judgement" path, but I've been around here long enough to know that similar threads end up that way. Just trying to get in front of the discussion in case it it goes off the rails.
 
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In the video, you didn't mention about any feedback from the stick during any of these maneuvers, and leads to believe that the pilot is not paying attention to what his aircraft is trying to tell him.
 
In the video, you didn't mention about any feedback from the stick during any of these maneuvers, and leads to believe that the pilot is not paying attention to what his aircraft is trying to tell him.

Interesting observation! Here's what I think is going on...

In the low speed spirals under discussion, the speed range is limited. In the RV-9A, speeds start at 70 knots and, even after the descending steep turn, don't change much, maxing out at around 100 knots. AOA never gets above 0.6, well below stall, and during the spirals per se, G force is less than 1.4. In other words, the airplane doesn't have much to say (!). And in the other airplanes in which I've flown Low Speed Spirals, I don't recall getting any cues in the stick (or wheel). (The one spiral that hit 2.18 G did that in the recovery, not in the spiral per se...)

The other point is that if the pilot is in a situation which motivated a steep turn to final, the attention paid to alignment with the runway is such that even if the airplane was trying to tell the pilot something, the pilot probably wouldn't notice it -- and that's a major point in base to final and other loss of control events. The NTSB report on the Learjet accident, NTSB/AAR-19/02, states this in Finding 8, as mentioned in the presentation. And there are many, many more similar examples to be found.

Great question! In the future, I'll try to be more attuned to any control system feedback, but my guess is that even the kinesthetic sensations will be masked by the visual inputs.

Standing invitation to anybody who wants to come fly the Expanded Envelope Exercises® with me in Savannah, including the Low Speed Spirals. These exercises are non-aerobatic, suitable for normal category, so you won't learn nearly as much in a short wing RV as you will in a more docile airplane.
 
The login request has been removed from webinar, so you can watch it without giving any information. This is standard NAFI practice a few days after the presentation.
 
Ed is correct, an airplane will be rock steady between 60% lift and L/Dmax (the 70-100 speed range at 1 - 1.4G's mentioned).

At less than 2 G's there would be little or no aerodynamic buffet in a 3/4/6/7, even at stall. 8's a bit different and can provide better buffet cues at 1-2 G's. Buffet cues in the 4 don't get noticeable until north of 2G's. Here's a 1.6 G stall in a 45 degree banked gliding turn--no aerodynamic warning: https://youtu.be/KTUKR6PiP8s. The stall occurs at a normal Vref, I'm simply asking for more G's than the airplane is capable of generating at that speed, IDLE power and bank angle (where the lift is pointed). Here's what's happening out on the wing as you approach the stall, notice how solid the airflow is even with the stall warning going off (set to FAR 23 criteria): https://youtu.be/W9Zr-Gd4IoI. Here’s a few actual stalls under the same conditions, and the take-away is how rapidly the stall progresses: https://youtu.be/j2H-ssR83_g.

It's a bit of a common misconception that a stable, descending gliding turn is "unloaded" (i.e., low G). A 45-degree banked gliding turn is still flown at 1.4 G's, just like a level turn, so stall speed is going to increase by about 15% and you don't have a lot of "energy/lift reserve" if you pull much harder at that bank angle.

Thoughtful presentation, Ed.

Fly safe,

Vac
 
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