Stall spins

[Mesteve]

I have read all of the NTSB reports for fatalities, and having watched Trent most recent video, it seems the PRELIMINARY (I am not trying to speculate, hence the separate post) cause was the same thing that caused most of the fatalities.

That makes me ask, what is it about this design that lends itself to the stall spin scenario? Is it the flaperons and the adverse yaw (that I thought was mostly mitigated with differential aileron control) or something else? Is it maybe something as simple as the way these get flown by some, being bush planes and all?

[bbs428]

Low and slow and steep turns ican bite you no matter what type plane your in.

The final report will be whatever it is.

That being said, All of us should know that Loss-of-control (LOC) accidents are at the top of the stats,
and stall-related events is a leading contender in LOC accidents.

Because of all this, I will be doing a lot of reviewing of what I'm already supposed to know
and get some quality Kitfox type-specific training prior to flying my plane like Stick & Rudder.

Food for thought....

http://www.aviationsafetymagazine.com/issues/36_10/features/Aircraft-Stalling-3-Basic-Kinds_11245-1.html

[Esser]

The design is not more suseptible to spins. In fact it’s hard to keep in a spin.

Get spin training. Obviously spinning 150’ above the ground is never is never going to end up well but that training might stop you from getting into that situation.

[t j]

We are taught that a spin can only result if the airplane is stalled and that stalls are caused by exceeding the critical angle of attack.


But burn this into your memory, the only thing that really causes a stall is the pilot pulling back on the stick.

[PropWash]

I fly a 182, and my home airport is in a tight valley such that when I turn in the pattern it has to be steeper than what one would normally do. I am glued to airspeed. It is a wake up call when you realize how quickly airspeed can drop when overlooked for just a few seconds. I think Nikk's crash is a good reminder to not get complacent (not that complacency caused the accident but I think it's likely). It can happen to any pilot no matter the level of experience.

[Shadowrider]

Stall speed is a misnomer. As others are saying, remember a stall happens regardless of speed it’s all about AOA. There is a reason business jets, well most all jets have and use AOA. We calculate ref speed based off of weight and temperature and that gets us close. Stall protection is based off of AOA. I have been on ref speed, (approach speed) and due to turbulence had the stick shaker go off. It’s pretty interesting to watch AOA jump around in turbulance and especially in a turn. Interesting facts below from web

Assuming a stall speed of 50 knots in level flight, at 60 degrees angle of bank the stall speed will increase by the square root of the load factor +2 (√2), which is approx 1.4. This means that, at 60 degrees angle of bank, the stall speed is increased by 40% to 70 knots.

[jiott]

Just a comment based on my own experience in my SS7. I have taken it up to about 5000' AGL several times to explore stall characteristics and have plenty of altitude to recover from whatever. Having gotten a pretty good feel for the stall characteristics power on and off, straight and in moderate turns, I decided to explore the envelope for accelerated stalls. I have tried speeds from very slow to 90 mph and then suddenly pull hard elevator in a steep, 60 to 70 degrees, turn. I could not get it to do an accelerated stall. It would always whip around very quickly and lose speed quickly while the nose would drop and put me into a fairly steep spiral dive. Nothing I could do with elevator or rudder would keep the nose even close to level. It would spiral down, NOT stalled, and could be easily flown out of the spiral at any time. Now I am no test pilot and maybe there are ways to stall it in this kind of maneuver, but I could not do it. Bottom line to me, it seems like an extremely safe aircraft that wants to naturally keep itself flying. But I got to thinking about Nik's accident, where he appeared to make a very steep abrupt turn low to the ground. In this condition your nose WILL go down even if you are not stalled, and there may not be enough altitude to recover.

Wondering if anyone else has explored this part of the envelope and what your results were?

[rosslr]

Yeah Jim, I did the same trials up high. I didn't push it right to the limits but certainly exaggerated a tight turn base-final and nothing. I have since installed an angle of attack indicated that I love. It is interesting to watch how it goes from green to yellow when simulating a tight base-final turn and red right on a stall 3 pt landing. It also indicates how turbulence can put the aircraft close to stall (red lights) very quickly on a final approach without sufficient buffer to compensate. Of course, we all know this in theory but I now use the AOA indicator over airspeed as my primary guide in tight manoeuvres and turbulent approaches.

I think it has been a very good investment that gives accurate and real time indications of how close to a stall you are and I also find it to be an excellent training aide.

cheers

r

[David47]

If you want to do an accelerated stall, try a high banked and steep climbing turn and pull the stick back all the way quite quickly - but just be aware there is a dynamic effect that may not stall the wing initially, but just hold it in because it ultimately will. Then if you want some real excitement, try it again put full rudder on and skid it. Be prepared to end up on your back, but you'd better know how to get out of that one ... :eek:

Did all this recently in some upset and recovery training in a Super Decathlon. Worth every $.

[jiott]

David, did you do this in a Kitfox or was it a Decathlon? Not saying it won't work in a Kitfox, but I think the Kitfox may behave differently in some maneuvers due to flaperons, etc.

[brjohnso]

Does anyone know how Nick adjusted the wings of his plane for washout? They were Trent’s old wings from his KF 5, and he put them on a different kf7 fuse. Isn’t there a matching that has to be done between the wings and the fuselage when the plane is built? Could a warp or twist in the wing cause one wing to stall before the other, making the plane more susceptible to a spin?

[Esser]

You can remove the old spar attach plates and re adjust the positioning but the model 5 and the model 7 in theory should be exactly the same attach point. All that e adjusts is wing sweep though. The strut attach points can be adjusted to change flying tendencies. I’m sure Nikk has his plane rigged properly or else it wouldn’t have flown nicely.

[aviator79]

I've only done a handful of stalls, power on, power, off, and in turns in a couple different kitfoxes, and I was surprised how docile they were. So to the original poster's question, I don't think there is anything inherent to the design that leads to these kinds of accidents. As someone else pointed out, LOC accidents are a leading cause of fatal accidents across all of general aviation.

Now I'm going to speculate a little bit. There may be a disproportionate number of Kitfox fatalities in this scenario for two reasons:
1) A Kitfox is comfortable flying slow, and maintains roll authority well into the stall, so Kitfox pilot may feel a little too comfortable maneuvering the plane with a thin stall margin.

2) Kitfox pilots are more likely to be flying low and slow, making non-standard approaches to difficult airstrips with tighter than normal turns. In these cases, there is insufficient altitude margin to recover from an unintended stall. I'll tell you as a CFI, that the reason you should practice stalls and recoveries is primarily so you learn your airplane's incipient stall characteristics. There is a BIG difference between recovering from a stall that you induced intentionally, and recovering from one that you did not intend. Stall practice is not to teach you to recover in this situation, it's to explore this portion of the flight envelope so that you correct before the stall happens.

I realize this conversation is happening while Nikk is recovering. My comments should be taken generally, and not directly connected with his accident.

[David47]

David, did you do this in a Kitfox or was it a Decathlon? Not saying it won't work in a Kitfox, but I think the Kitfox may behave differently in some maneuvers due to flaperons, etc.

In a Decathlon Jim. And yes, a Kitfox may react differently. On that point, it would be good to get some input from John McBean or Paul Leadabrand on how, in our case, a 7SS would behave in those manoeuvres before attempting them. The Decathlon is obviously ok, not so sure about the 7SS or any other model for that matter.

[jmodguy]

I belong to a flying club and this link was recently emailed to the membership.
Good info

https://vimeo.com/7479092

[efwd]

Thanks Jeff. Having trained so long ago, that video was great.

[Mesteve]

I belong to a flying club and this link was recently emailed to the membership.
Good info

https://vimeo.com/7479092

Valid input, even (more so) for those of us more recently out of training....

[Farflyer]

Stalls and spins.

I think we all agree it’s important to understand all aspects of aviation. If you look around in your local aviation community, I bet you could find a person or aerobatic club who would welcome the opportunity teaching you stalls and spins.

I was fortunate to have a retired International aerobatics competitor in my area. I to was and still concerned about stalls and spins. My private instructor knew the basics, but I felt I needed more.

The retired aerobatic competitor’s, Olie Pash, method of teaching was real world. I will never forget his words “Lets see what you know. My aircraft”. Each scenario he put me in, I had to struggle in finding a solution of getting myself out of and recover the airplane. His teaching method was from the known. A climbing right turn power on stall and a rudder kick. To the unknown, upside down in a flat spin.

In 1.5 hours of instruction, he introduced me to all manner of situations I could get myself and just as importantly others might put me in. He would brief the scenario and let me maneuver the airplane into each situation, so I could feel and see how each scenario unfolded, then let me struggle on how to get out of it. Olie would make sure I understood how we got into the stalls and spin and the method on how to get out of it. I believe it is some of the best instruction and money I have ever spent in flying.

Just my 2 cents.

We learn from others and sometimes unfortunately from their mistakes. Olie passed on his knowledge. We all need to do the same.

http://flyingmuseum.com/hall-of-fame/2012-olin-olie-pash/