Stall / spin avoidence

[Ed Cesnalis]

Which gives the bigger safety margin for avoiding a stall/spin entry on the left base to final turn?

 

• Coordinated turn
  
• Slipped turn
  

[Jim Meade]

Gosh, CT, I know there is a difference in P-factor, torque, perspective and other factors but I'd also like to know the answer for the right base to final turn. I hope this doesn't complicate the expected plethora of responses.

[FlyingMonkey]

Well, it's a skidding turn that causes the dreaded base to final stall/spin scenario...a slipped turn would keep you as far as possible away from that condition, so you can make a good argument that the slipped turn is safer.

[Jim]

What Andy says is what I was taught.

[Anticept]

I'd say keep it coordinated unless you are trying to drop altitude in a rush (then slip it, just keep that inside-the-turn wing above stall speed!). Adding margin for spin avoidance means you're sacrificing a lot of airspeed, and many airspeed instruments don't read correctly uncoordinated...

[IrishAl]

Surely it's coordinated.  

Flying coordinated will keep you flying at the lowest possible airspeed.

And, because you can't spin when coordinated, it's got to be the best option. 

[FlyingMonkey]

I'd say keep it coordinated unless you are trying to drop altitude in a rush (then slip it, just keep that inside-the-turn wing above stall speed!). Adding margin for spin avoidance means you're sacrificing a lot of airspeed, and many airspeed instruments don't read correctly uncoordinated...

 

That's what I do.  I have gone straight into a hard slip if I'm really high at the base/final turn, but usually I just try to keep the ball centered unless I have a reason not to.

[Ed Cesnalis]

Well, it's a skidding turn that causes the dreaded base to final stall/spin scenario...a slipped turn would keep you as far as possible away from that condition, so you can make a good argument that the slipped turn is safer.

 

Its more than a skidding turn that causes the spin entry.  I do agree with you, its really hard to see how a left rotation would start when using a lot of right rudder.

 

Surely it's coordinated.  

Flying coordinated will keep you flying at the lowest possible airspeed.

And, because you can't spin when coordinated, it's got to be the best option. 

 

Do you have a 1,000' runway?  I'm generally not lowest possible IAS at base to final, I"m still at 55kts.

[Ed Cesnalis]

I'd say keep it coordinated unless you are trying to drop altitude in a rush (then slip it, just keep that inside-the-turn wing above stall speed!). Adding margin for spin avoidance means you're sacrificing a lot of airspeed, and many airspeed instruments don't read correctly uncoordinated...

 

I want to know which approach (<-get it?) has the biggest margin not so that I can add margin but more so I know which side to error on.  

 

I find it curious that student pilots seem concerned about being uncoordinated but seldom seem concerned about skidding.  In fact I have heard more voice concern over slipping than skidding.

 

I also find it curious that they are taught to limit their banks, limiting their banks is how the controls get crossed.  I think in terms of too steep (slip) vs too flat (skid) and error on the side of steep, so I don't limit my bank in the pattern.  I do trim early and maneuver without any back pressure.

[ralarcon]

I try to stay coordinated ,always keeping airspeed up (ball center} all the way to final  and then "slip", if needed,  to lose altitude or compensate for cross winds. 2 cents.

 

Cheers

[Jim Meade]

Everybody back off for a minute, check out this BruceAir website which discusses and shows videos of this very discussion, and then re-enter the discussion.

 

http://www.bruceair.com/stall-spin/stalls.htm

[ralarcon]

Everybody back off for a minute, check out this BruceAir website which discusses and shows videos of this very discussion, and then re-enter the discussion.

 

http://www.bruceair.com/stall-spin/stalls.htm

Excellent article , very good video, thanks. Seems to me if you don't stall you do not spin.  So it seems to confirm my 2 cents comment. I have been told, (by a trusted source) ,that the CTSW and the CTLS are very spin resistant . Not impossible to spin, but very hard to.

 

Cheers

[WmInce]

. . . "I have been told, (by a trusted source) ,that the CTSW and the CTLS are very spin resistant . Not impossible to spin, but very hard to." . . .

 

That leads to the question, what are the proven spin recovery characteristics?

Once the airplane enters a spin, how hard is it to recover from it?  How many turns with the AOI recovery technique?

 

What is the reference for the data?

[Tom Baker]

Excellent article , very good video, thanks. Seems to me if you don't stall you do not spin.  So it seems to confirm my 2 cents comment. I have been told, (by a trusted source) ,that the CTSW and the CTLS are very spin resistant . Not impossible to spin, but very hard to.

 

Cheers

I have had two occasions in a CTSW doing stalls with 40° flaps where the airplane unexpectedly broke hard and dropped the nose. Once was with a student doing a stall, and they didn't keep the ball centered. The other was me flying demoing a stall, but it was real rough and gusty. It is likely that a bounce let the airplane become un-coordinated. I have never had that happen with any other flap setting or in the CTLS.

[ralarcon]

That leads to the question, what are the proven spin recovery characteristics?

Once the airplane enters a spin, how hard is it to recover from it?  How many turns with the AOI recovery technique?

 

What is the reference for the data?

If I remember correctly, the POH has instructions on spin recovery. Do not know anybody that has tried to spin this aircraft of purpose, except maybe the test pilots who originally tested the design, and that data should be documented in FD's test characteristics documentation. Do not know if that is available to us. Personally, I'm NOT a very experienced pilot with thousands of hours of experience , but to me the CTLS is a very docile aircraft that seems, inherently, to always want to fly. And, in my experience, you have to fly it to the ground because it is hard to stall. I remember, on my check ride , the examiner tested me on a power  turning stall ( at 15 degree of flaps), and the airplane did not want to stall. If it did it was  imperceptible.

 

Cheers

[FlyingMonkey]

My instructor told me that spin recovery in the CT(SW) is conventional, meaning the PARE technique works. When I asked if he had spun it, he gave me a sly smile and said "Of course not, spins are prohibited and that would be illegal."

[Anticept]

Flight Design aircraft have been shown in flight testing to be recoverable from spins. However, they don't want people spinning their planes, so they didn't pursue certification as spelled out in EASA.

 

Same with sportsman aerobatics (positive G only). They have been shown to perform sportsman aerobatics very well, but they don't want people doing aerobatics!

[Roger Lee]

In 1997 an FD test pilot pulled the cute because he got in a maneuver he couldn't recover from. I think anyone purposefully spinning a CT is not a very bright individual. If a pilot is willing to go this far how far will he go in failing maint., pre-flights, and risk taking with passengers? Done wrong what stresses will he cause on the plane's stab which is our weak point? A CT pilot in Italy, like all of us, was warned not to do aerobatic type maneuvers. So at a show he is low, fast and does 1 too many hard maneuvers. He's dead now because the stab failed at 75'.

 

Like Forest Gump said: Stupid is as stupid does.

[Anticept]

A CT pilot in Italy, like all of us, was warned not to do aerobatic type maneuvers. So at a show he is low, fast and does 1 too many hard maneuvers. He's dead now because the stab failed at 75'.

 

Low, fast and hard maneuvers is the key there. Sportsman aerobatics are supposed to be gentle positive G maneuvers for beginners. Big and loopy, with as little inverted flight as possible.

 

As for the CT test pilot: what maneuver, and are we talking about the original CT? There's not much in common to today's CTs.

[FastEddieB]

Low, fast and hard maneuvers is the key there. Sportsman aerobatics are supposed to be gentle positive G maneuvers for beginners.

I took the privilege of holding what I think are key words here.

 

An aileron roll or a slow roll can be a gentle positive G maneuvers. You can find a video of Bob Hoover doing one in an airliner with a glass of water on the panel, though that might have been a barrel roll.

 

But...

 

I've done a lot of basic aerobatic instructing, and it's very common for beginners to let the nose fall out of any roll. When that happens, speed builds up very rapidly, and can approach or exceed Vne very rapidly. And the pullout can end up being not quite so gentle.

 

A fellow tried one of these gentle positive G maneuvers in a Cirrus and two people died in a Florida swamp.

 

I have never done aerobatics in a plane not certified for them, and would recommend others do likewise.

 

I assume Anticept was NOT recommending aerobatics in a CT, but I think his post might be read as minimizing the risk of said aerobatics "if done right". I assume he will clarify that was NOT what he meant.

[Anticept]

Basically, don't do them unless you know what you are doing. There's a reason aerobatic planes are certified to extremely high Gs.

 

Bob Hoover does barrel rolls. And he did it in an aero commander.

[FastEddieB]

Bob Hoover does barrel rolls. And he did it in an aero commander.

Can we assume that involved an FAA waiver after he demonstrated appropriate abilities?

[Anticept]

Can we assume that involved an FAA waiver after he demonstrated appropriate abilities?

 

Only at airshows.

[FlyingMonkey]

 I think anyone purposefully spinning a CT is not a very bright individual.

 

Like Forest Gump said: Stupid is as stupid does.

 

I'm not disagreeing with you...but the same has been said of people who purposely shut down their engine in flight...  

 

There is "not smart" from a flight safety perspective, and "not smart" from a legal perspective.  Obviously anybody intentionally spinning a CT is well into the "not smart legally" zone.  From a safety perspective, I'd say it depends...doing maneuvers for which an airplane is not designed or approved is well beyond my comfort zone and into test pilot territory, but there are a lot of very competent, experienced pilots out there for which that is well within their skill set.

 

Various people accept differing levels of risk when they fly.  If they understand and accept the risks, well...it's their choice to make, IMO.

[FlyingMonkey]

I've done a lot of basic aerobatic instructing, and it's very common for beginners to let the nose fall out of any roll. When that happens, speed builds up very rapidly, and can approach or exceed Vne very rapidly. And the pullout can end up being not quite so gentle.

 

 

True.  The Sonex factory points to a particular incident like this to demonstrate the strength of their airframe, and I have confirmed this story with the pilot involved.  He made an aileron roll from level without first pulling the nose up.  Predictably, the nose fell down sharply and his speed built up quickly.

 

Vne for a Sonex is 197mph.  He pulled out of the dive at 254mph.  No damage was done to the airplane, which is a testament to the strength and conservative margins of the airframe.  But it could have gone much worse.  

 

A pilot of any skill level can damage an airplane or cause injury performing *any* maneuver.  Just look at how many airplanes are wrecked on landing, arguably the most common maneuver we all practice.