Tail Icing

An aerodynamic stall caused by ice is harder to explain in the absence of a lift-producing airfoil.
A flat plat stall looks like this (airflow from left to right):
kHr6r.jpg


Just like a 'traditional' airfoil, ice may trip this kind of separation earlier.

To see what a tail stall looks like on a tail with a downforce, turn your screen upside down :) (airflow will now be from right to left)

Nauga,
and his separation anxiety
 
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Interesting pic. Thanks. Upside down for the purposes of this discussion. And I still think deflection is the primary force. Can’t prove it but I know who to ask, and I’ll be spending a couple of days with him next week. Very interesting topic.
 
And I still think deflection is the primary force.
Deflection is not a force. Deflection changes the angle of the surface with respect to the airflow, changing the effective angle of attack of the surface and as a result changing the lifting force the surface produces.

Nauga,
Naviered and Stoked
 
If your pic is inverted to represent my Cub tail how does the tail raise/nose drop in a tail stall?
 
If your pic is inverted to represent my Cub tail how does the tail raise/nose drop in a tail stall?
If the tail is producing a downforce to balance and the downforce goes away the nose will pitch down. Whether or not that's representative of your Cub I can't say.

I don't think tail stalls are nearly as big an issue as this thread might lead one to believe - but I have little experience with the type of icing that might make it worse.

Nauga,
stalling
 
Curious.. I know the shape is different, I wonder in real world testing what the airflow differences would look like. I imagine that even if you were to stall the tailplane the subsequent recovery would be easier

I was basing my "stabilators won't stall" on the description in this from @jordane93 's post 5. https://www.faasafety.gov/gslac/ALC/course_content.aspx?cID=33&sID=160&preview=true
It desribes how the horizontal stabilizer will block airflow from the elevator. I jumped to a conclusion based on that. But after reading on in this thread it's obvious a stabilator in itself can stall. My post edited.
 
If you've got the altitude, raising the flaps and lowering the nose (forward stick/yoke) will both reduce tail AOA.

o_O There are slots on Cessna Cardinal stabilators to treat a stabilator stall issue. F-4's had them too. T-45 just got honkin' big strakes (called "SMURFs" for a while)...all to deal with tailplane stall.

Nauga,
and the 'phantom dive'

Hadn't heard that before. Always thought it was to reduce the 'authority' of the stabilator because so many people were slamming the tail down during flare to landing. And probably stalling the wing because of to much nose up force for a given amount of back pressure at the yoke. But I'm not to sure about it being because of the stabilator itself stalling
 
What is the typical small airplane reaction to a tail stall?

I am not sure if the tail stalled or the wings stalled. My experience was in a Cessna 414. It was night time and I had been in a hold in the clouds while waiting for the cargo C-402 to finish his 8 attempts to get into Gallup. I had 2 more planes above me in the hold and 2 more planes in bound. FINALLY, the 402 went away and I got to do an approach that I knew would get me in. I had been picking up ice while holding, a fact I kept reminding the cargo pilot about.

For those that don't know, the C-414 boots doesn't shed ice very well at slow speeds. Usually I used 120 indicated for an instrument approach in the 414, but because of the ice I decided to use 140 and no flaps. I did the approach, broke out a little above minimums, and as I got within a few feet from landing I leveled off and pulled out the power to slow down and see what would happen. At 110-115 indicated the pressure on the yoke went limp and the plane fell the final couple of feet to the runway. Not pretty but the plane could be used again...


For those that are wondering...... the 402 was doing a GPS approach. I did the GPS WAAS approach and got in.
 
Hadn't heard that before. Always thought it was to reduce the 'authority' of the stabilator because so many people were slamming the tail down during flare to landing. And probably stalling the wing because of to much nose up force for a given amount of back pressure at the yoke. But I'm not to sure about it being because of the stabilator itself stalling
The slot on a Cardinal stab will *increase* the authority in the nose-up direction.

Nauga,
vortically challenged
 
The slot on a Cardinal stab will *increase* the authority in the nose-up direction.

Nauga,
vortically challenged

Reading more about it, yeah, it was about stabilator stalling along with some other things.
 
In the Cub world we do mods like extend the airframe to improve slow speed tail authority since we have wing mods that allow stall speeds in the 17-18 mph range. Rudders and elevators have gotten bigger, wings are longer, flaps are longer, chord of flaps and ailerons is deeper, heck, everything's been modified to improve slow flight but I've never heard of a tail stalling. I guess I have a research project!
 
I don't think so. Apples and oranges. As I understand it Caravan tails lift. My plane's tails provide down force. Again, with a down force tail, what would happen if it iced?
I don't know of any conventional plane where the empennage does anything else other than push down. There are consequences to stability otherwise. Whether a tail pushes down, or lifts up, a stall would do the same thing as a wing stall: stop providing 'lift', in whatever direction; the nose would drop on a Caravan or a Musketeer or an Ovation.
 
On susceptible planes how about a couple of automotive back up cameras looking at the stabilizer to gauge ice build up and boot failure? Naaah, who wants a solution that only costs a few of thousand dollars.
 
On susceptible planes how about a couple of automotive back up cameras looking at the stabilizer to gauge ice build up and boot failure? Naaah, who wants a solution that only costs a few of thousand dollars.

On the PIpers I've flown, both my Archer and now the Lance I can look over my shoulder and see most of the front of the stabilator from the pilot's seat.
 
On susceptible planes how about a couple of automotive back up cameras looking at the stabilizer to gauge ice build up and boot failure? Naaah, who wants a solution that only costs a few of thousand dollars.
General aviation *hates* advancement and any kind of technological improvement.. I swear, outside of Garmin we're stuck in the 1950s (at best) technologies
 
General aviation *hates* advancement and any kind of technological improvement.. I swear, outside of Garmin we're stuck in the 1950s (at best) technologies
Given that, even if someone had a nice, water-cooled, long lasting, reliable, and light Jet-A burning engine package that would directly replace a 360 four banger, they'd have to certify the engine, and then certify (by STC) its installation in every single airframe into which it would fit. (Note that even for new airplanes and new engines, the airframe/engine package must still be certified, as well)
So there's no money in it, and technology goes forward when money can be made (that Samsung Note in my pocket is an example.)
 
General aviation *hates* advancement and any kind of technological improvement.. I swear, outside of Garmin we're stuck in the 1950s (at best) technologies
What's the primary structural material in your Cirrus? Not all advancements are flashy lights and noisemakers, nor are they expensive 'fixes' for corner cases that most will never encounter.

Nauga,
who can't always afford what he wants
 
certify the engine, and then certify (by STC)
that's part of it, but I also feel like there's a general mindset among the community that what we have now is good enough.. I mean we still have people who don't like glass and prefer analog.. and the Cirrus gets plenty of hate

So cost is part of it, but there's not a whole lot of will either it seems..

LOL, I actually had a blurb in there about Cirrus but I have enough of the Fanboy stigma here so decided to remove it.. even that though, outside of many conveniences, has an overall fit and finish and technological relevance as a mid 90s Saturn sedan.. the last generation of the TTx is superior in several ways, including a superior avionics package and little ergonomic conveniences like having digital climate control..
 
PS - laws and regulations are written in blood and have created an overall safe aviation community for us.. however they also treat a near impenetrable barrier to entry and the bureaucratic process stifles progress.. the Wright brothers never would have taken flight if they had the kind of obstacles to grapple with that we do today.. really no great leaps of mankind would have occurred
 
the Wright brothers never would have taken flight if they had the kind of obstacles to grapple with that we do today.. really no great leaps of mankind would have occurred
Experimental aviation operates today in the much same fashion as the Wright brothers. I'm not just talking about amateur-built.

By cherry-picking a single word from my post you completely ducked the question I asked and have apparently ignored the advancements that have been made in composite materials and structures and strength-to-weight and instead complain about fit and finish.

A solar-powered electric airplane just flew around the world, FFS.

If there's no advancement in GA, how do you describe the G650 and fly-by-wire? If you're complaining that this level of technology doesn't trickle down to light singles, pay up. The business case for light single investment is terrible, so who do you think should shoulder the cost? What corners are you willing to cut in certification and testing?

Nauga,
getting **** done
 
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Experimental aviation, including E-AB, is all about innovation. These are exciting times.
 
Experimental aviation operates today in the much same fashion as the Wright brothers. I'm not just talking about amateur-built.

By cherry-picking a single word from my post you completely ducked the question I asked and have apparently ignored the advancements that have been made in composite materials and structures and strength-to-weight and instead complain about fit and finish.

If there's no advancement in GA, how do you describe the G650 and fly-by-wire? If you're complaining that this level of technology doesn't trickle down to light singles, pay up. The business case for light single investment is terrible, so who do you think should shoulder the cost? What corners are you willing to cut in certification and testing?

Nauga,
getting **** done
I don't cherry pick for a straw man reason.. but to save space and use certain parts as prompts for discussion.. so no harm intended

What's the primary structural material in your Cirrus? Not all advancements are flashy lights and noisemakers, nor are they expensive 'fixes' for corner cases that most will never encounter.
here's the whole post, quoted..I have long lauded (here, and in general) carbon fiber and composite for it's use as a superior material to metal (in many, though not all, applications).. and Cirrus / Lancair / Diamond / etc., are using it now (and Grumman before). I omitted Cirrus from my post because I'm trying to write fewer posts that cite the plane as perfect.. and kind of to my point everyone who doesn't fly a Cirrus seems to hate it.. because they're "modern"

advancement is slow, and costly. The FAA does fine work, but because they don't need to "stay in business" or be cost competitive they could care less about the costs that regulations incur on the private entity looking to get certified.. saying that the solution to these barriers to entry is to "cut corners" is wrong.. there are ways to run things more efficiently and reasonably in a time and cost sensitive matter.. in my experience doing business with entities that exist by default has been underwhelming.. take the DMV for example.. spend 2-3 hours to fill out and submit a form

anyway, I am not interested in arguing with strangers on the internet.. I'm not satisfied that our piston GA planes are about 20 years behind the tech bell curve (at best, in some cases 50 or more years). Yes, it's expensive.. but accepting the status quo as "sorry bud, that's just the way it is" isn't generally a palatable answer to me
 
Experimental aviation, including E-AB, is all about innovation. These are exciting times.
..and this proves my point, that the way to advancement is to bypass many portions of the regulatory process

anyway, some people just "auto disagree" with Tantalum
 
..and this proves my point, that the way to advancement is to bypass many portions of the regulatory process...
The regulatory process is explicitly set up to allow developers to defer parts of the certification process to mature technology. GA airplanes and improvements don't just spring up out of whole cloth and undergo cert.

anyway, some people just "auto disagree" with Tantalum
...while others have viewpoints that differ significantly from yours and choose to not remain silent.

Nauga,
waiting for the band to start
 
The regulatory process is explicitly set up to allow developers to defer parts of the certification process to mature technology. GA airplanes and improvements don't just spring up out of whole cloth and undergo cert.

...while others have viewpoints that differ significantly from yours and choose to not remain silent.

Nauga,
waiting for the band to start
Maybe I'm seeing the past better than it was.. but you had Mooney, Beechcraft, Cessna, Piper, (and more!) putting out all sorts of variations to their product lines and the GA world (for a few decades) seemed to thrive. I wish I was growing up in an era that wasn't forcing people to choose between spending $1M for something modern or fly rental 172s... or buy something with half missing logbooks that's 30 years old.. or embark on the exciting world of EA.. but it is what it is I suppose.. and should I have more money and time EA is where I'll likely be spending my future so I can tinker with my arduino gadgets, etc.

If you're complaining that this level of technology doesn't trickle down to light singles, pay up. The business case for light single investment is terrible, so who do you think should shoulder the cost?
basically. yes. (bolded the part I'm responding to so I can retain your quote in its entirety)


BTW:
The solar powered plane thing was cool, I followed that story closely.. my gripes lie with our (my?) little niche of the aviation world.. single engine piston GA
 
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