Diana
Final Approach
Rich, thanks for answering my initial question.
Falling leaf stall?
- Thread starter Diana
- Start date
rstowell
Pre-Flight
Rich, thanks for answering my initial question.
Hi Diana, you're welcome!
Two more things to note if you do the exercise with partial power:
First, you may not need to pull the stick/yoke all the way aft -- just pull it far enough aft to encounter the onset of stall buffet, then hold that position until you decide to stop.
Second, the Citabria has sufficient rudder authority to correct much greater heading deviations than something like a Cessna 150 or 172.
In the 150/172, your "window of controllability" is about 20 degrees wide on either side of the original heading. Once the airplane deviates beyond that, even full opposite rudder applied and held will not return the airplane to the original heading. There is, however, sufficient rudder authority to prevent a spin. So the airplane ends up performing a stalling, slipping, spiral -- not able to return to heading, not spinning, just bobbing in and out of stall buffet as it spirals down in a slip. If one were so inclined, you could execute a 360 degree turn in this manner, without any increase in airspeed.
Since this would then be a slipping, turning stall, the recovery is straightforward: break the stall (stick/yoke forward), return to coordinated flight (release the rudder input), return to straight & level.
BTW, on the off chance that anyone here might be interested, I'm trying my hand at a new blog: www.richstowell.com/blog
Rich
www.richstowell.com
midlifeflyer
Touchdown! Greaser!
Rich, I think it's absolutely terrific that you are hanging out here!
rstowell
Pre-Flight
Hi Mark, thanks for that! I've been known to hang around some good and some not-so-good places. This seems like one of the good places...
Rich
www.richstowell.com
etsisk
En-Route
Rich, if you could check your private message inbox here on the board...
K
KennyFlys
Guest
Are you begging for free aerobatic ride again??? Gosh!Rich, if you could check your private message inbox here on the board...
CJones
Final Approach
OK.. I had to try this out yesterday while out putzing around yesterday.
Me + full fuel in the RV:
Power Idle - 60KIAS - +7.5* attitude - no flaps => -800fpm, no stall. There wasn't much 'flutter' to it. Once I got it trimmed out, I could maintain the airspeed and attitude all the way to the ground (nearly no rudder input needed). If I pulled back to +10* attitude, slowed to ~57KIAS => sharp stall => Power idle, neutral elevator, recovers itself at 60KIAS.
Between the 57-60KIAS, there was a little 'breaking' action where it seemed like it was trying to stall, but couldn't quite do it. Is that where the "falling leaf" stall occurs? Should I try to maintain it within that small area of "not really flying, but not yet stalling"? It was a much more 'dynamic' area than the 60KIAS.
Also, when doing this, the stick wasn't anywhere near full-back.
Me + full fuel in the RV:
Power Idle - 60KIAS - +7.5* attitude - no flaps => -800fpm, no stall. There wasn't much 'flutter' to it. Once I got it trimmed out, I could maintain the airspeed and attitude all the way to the ground (nearly no rudder input needed). If I pulled back to +10* attitude, slowed to ~57KIAS => sharp stall => Power idle, neutral elevator, recovers itself at 60KIAS.
Between the 57-60KIAS, there was a little 'breaking' action where it seemed like it was trying to stall, but couldn't quite do it. Is that where the "falling leaf" stall occurs? Should I try to maintain it within that small area of "not really flying, but not yet stalling"? It was a much more 'dynamic' area than the 60KIAS.
Also, when doing this, the stick wasn't anywhere near full-back.
rstowell
Pre-Flight
Sounds about right -- a properly constructed RV displays relatively benign behavior w.r.t. roll-off. Nice sharp stall buffet, sure, but little tendency to want to bite toward a spin unless provoked.
Try the same thing carrying a little power and the buffet will be more intense. You'll find that you will need to play a bit more with your feet to counter roll-off, too (but not nearly the footwork required in Diana's Citabria
).As stall buffet is reached (as you observed, the stick isn't necessarily all the way back), the RV will typically have more or less three sharp, staccato raps of stall buffet, followed by a brief respite (airflow momentarily reattaches), followed by the sharp, staccato raps as airflow separates again, then respite, and so on.
I see you have an RV-7A. I taught acro to a local RV-7 driver about a year ago. We did loops, rolls, wingovers, unusual attitude recoveries, and spins up to a full turn in each direction--fun airplane! They're all fun, actually...
Rich
www.richstowell.com
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etsisk
En-Route
And I'm not gonna quit until it works with SOMEONE!!!!Are you begging for free aerobatic ride again??? Gosh!
CJones
Final Approach
Sounds about right -- a properly constructed RV displays relatively benign behavior w.r.t. roll-off. Nice sharp stall buffet, sure, but little tendency to want to bite toward a spin unless provoked.
Try the same thing carrying a little power and the buffet will be more intense. You'll find that you will need to play a bit more with your feet to counter roll-off, too (but not nearly the footwork required in Diana's Citabria
Actually, I did run through a few of them at ~1100RPM, but it wasn't much fun. I kept climbing!
You're right, though, it did require a bit more footwork.You nailed it! Bump, bump, bump, fall.
That is on the "to-do" list. We actually bought 'chutes and even had them re-packed in anticipation of learning some 'gentleman aerobatics', but we've never gotten around to it. Not that the 'chutes could ever be used - getting the canopy open and crawl out of that thing in a pinch would be a miracle in itself.