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Antonov An-2 is available

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7 minutes ago, Stearmandriver said:

Well now, this is giving me pause about buying this thing just yet.

No real AN-2 time here but a lot of time in various biplanes, and I've never met one that doesn't fall out of the sky without power.  It's almost a mantra I've chanted at new Stearman owners during checkouts: "nothing you've ever flown or ever will fly comes down like a Stearman."  The surface area and induced drag of two big fat wings pretty well guarantees this for most biplanes.

All you gotta do is look at an AN-2 to understand the same rules apply.  This thing should be a brick 😉.  Hope they get that squared away.

Well neither am I "but I did stay in Holiday Inn" (if you ever seen this commercial

if we are talking about 1 G stall:

According to the operating handbook, the An-2 has no stall speed. A note from the pilot's handbook reads: "If the engine quits in instrument conditions or at night, the pilot should pull the control column full aft and keep the wings level. The leading-edge slats will snap out at about 64 km/h (40 mph) and when the airplane slows to a forward speed of about 40 km/h (25 mph), the airplane will sink at about a parachute descent rate until the aircraft hits the ground.

https://en.wikipedia.org/wiki/Antonov_An-2

 

 

"When Gothard suggested we try some stalls, I was eager. I knew the huge wings would generate a ridiculously low stall speed, but I had no idea it would be as slow as it was. I reduced power on the big 1,000 hp Shvetsov radial and watched the airspeed wrap backward around the dial. As we decelerated, the Antonov’s automatic leading-edge slats banged in and out together or independently when lift was asymmetric. Wrap the Colt into a steep turn, and the slats would adjust to help keep the wing flying.

Speed dropped through 60, 50 and finally all the way down to 40. At that point, the slats were fully extended and the Colt set up a gentle mush downhill, still under total control with no tendency to roll or manifest any other nasty characteristics.

I turned to Gothard and said, “That’s impressive for such a big airplane, a 40-knot stall.” Gothard smiled. “Those aren’t knots,” he said.

“Okay,” I said, “Forty mph is even more amazing.” The owner grinned even wider and said, “Those aren’t miles per hour.”

My God, I suddenly realized, the ASI was calibrated in kilometers. Stall speed was an indicated 40 kph, equal to 22 knots. Perhaps coincidentally, that’s exactly what the book suggests."

https://www.planeandpilotmag.com/article/flying-the-worlds-biggest-single-engine-biplane/

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I have come across AOPA article that mentions  handling AN-2 from US pilot perspective :

"Stall speeds are difficult to determine because there is no identifiable stall warning or break, nor is there a stall-warning indicator. Controlled descents can be made at 25 KIAS with the yoke held fully aft. According to the pilot's operating handbook, "an inadvertent stall is impossible."

During an approach to a full-power stall (if there is such a thing in the Colt), you can run out of right rudder and not be able to arrest the left yaw.

The AN–2 has a best-glide speed of 65 knots, but landing approaches are usually made with power because this is better for the engine.

During the approach, wing flaps are deployed incrementally by pressing with your left thumb a spring-loaded button on the left side of the throttle. It's a handy feature that enables you to lower the flaps (40-degree maximum) without removing a hand from the throttle or control wheel.

Your first arrival is likely to be made with a thud, as mine was, because it is initially difficult to adjust to flaring a single at a height of 20 or 30 feet. The slats deploy automatically during the flare and if things work out properly, the Colt sort of "squishes" onto the ground in three-point attitude. It is something like landing on a wet sponge.

Crosswind landings can be a problem. The aircraft touches down so slowly (28 knots, according to GPS) that the rudder has lost much of its effectiveness."

https://www.aopa.org/news-and-media/all-news/2001/october/pilot/antonov-an-2


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2 hours ago, sd_flyer said:

If we are talking about 1 G stall:

According to the operating handbook

Er?  I thought we were talking about drag?  I have no trouble believing that the plane can fly very slowly before a stall, but all the reasons that it can add drag as well.  This thing should be very, very draggy.

When I say that nothing falls out of the sky like a Stearman, I'm not talking about stalling.  The airplane actually has a very tame stall.  I'm talking about drag; when you pull the power to idle, to maintain a normal approach speed you have to shove the nose downhill STEEPLY.  It's no exaggeration to say that if you can physically see the runway in front of the lower wing, you can get down and land on it no problem.  (In a full slip it's even better, it comes down noticeably more vertically than it moves forward horizontally.)  But even without a slip, it's a brick.  The AN-2 definitely should be as well.

This is an aspect of the flight model that the DC Designs Stearman actually gets quite right, if you want to see what I'm talking about.  I was actually surprised by this, as it's not something that folks without biplane time would be expecting, so either the guy who did their flight model has some experience, or the base physics of the sim worked really well in this case.  There are a few characteristics of the Stearman FM I've tweaked for realism, but the drag is right on.

Edited by Stearmandriver

Andrew Crowley

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1 hour ago, sd_flyer said:

According to the pilot's operating handbook, "an inadvertent stall is impossible."

Soviet era propaganda at it's best. 😁 There's no such thing as a wing that cannot be stalled - and if it can be done intentionally, it can be done inadvertently.  

Might take a little g, but I have no doubt it can be stalled.  👍

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Andrew Crowley

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7 hours ago, TheFamilyMan said:

Just a minor nit, which may be a MSFS problem.  In VR when direct sunlight hits the banks of dip switches, none of them cast a shadow.  Seems some of the other controls exhibit this behavior too 😞

Other aircraft don't seem to have this problem as bad.  Yeah I know, this is splitting hairs here on an otherwise fabulously detailed and crafted ride.

I had to check that. All fine here, the switches are thin so you have to 'up' the shadow resolution. Contact shadows - Ultra and Shadow maps to 4096 (In the Usercfg.opt).

Edited by Gerwil
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40 minutes ago, Stearmandriver said:

Er?  I thought we were talking about drag?  I have no trouble believing that the plane can fly very slowly before a stall, but all the reasons that it can add drag as well. 

Well that is thing it doesn't really aerodynamically fully stall by many accounts. Since neither me or you flown it the best explanation I found here:

"The horizontal tail can't make sufficient down force to slow the plane to get the slatted wings to stalling AOA. With the slat system, the stalling AOA will be perhaps 10 degrees higher than without. With the AN2's large wing area, to get the slatted wings to stalling AOA might require the speed to drop to, say, 20 kt. But the tail simply runs out of down-push before that angle is reached, in this case at 25 kt, so no stall can occur and the airplane settles into a near vertical mush as long as you hold the full up elevator."

By all means reaching critical angle of attack doesn't equate to airplane controllability which Antonov 2 still retain even at 20 kts


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6 minutes ago, sd_flyer said:

By all means reaching critical angle of attack doesn't equate to airplane controllability which Antonov 2 still retain even at 20 kts

By all means, stalling an airfoil has absolutely nothing to do with airspeed, but only with AoA.  We only use airspeed as a proxy indication of AoA, but that only works under 1g.  A surprising number of pilots still don't understand this.  I really think we've dumbed down flight training too much over the years, in an effort to make learning to fly less scary and more accessible.  Removing spins from the private pilot syllabus was a terrible idea.

Any airplane can be stalled at any airspeed, in any attitude.  The only thing that causes a wing to stall is exceeding the critical angle of attack.  There's no such thing as an airplane that cannot be stalled.  That's neat, that under 1g, the Antonov elevator doesn't have the authority to exceed the critical AoA... Under a different load factor, it certainly does - and these are the conditions in which an inadvertent stall usually occurs.

None of this has anything really to do with drag, other than the fact that all the features that make the AN-2 able to fly slowly actually add drag to it.  Just looking at it, you can tell that it should be slow (it is), and that it should come down steeply while maintaining a given airspeed without power.


Andrew Crowley

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1 hour ago, Stearmandriver said:

Soviet era propaganda at it's best. 😁 There's no such thing as a wing that cannot be stalled - and if it can be done intentionally, it can be done inadvertently.  

Might take a little g, but I have no doubt it can be stalled.  👍

Here is practical aerodynamic of Antonov 2. I know it's in Russian but we can still see math 🙂

http://flyguy.ru/avia/wp-content/uploads/Практическая-аэродинамика-самолета-Ан-2-М.Н.-Шифрин.pdf


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8 minutes ago, Stearmandriver said:

By all means, stalling an airfoil has absolutely nothing to do with airspeed, but only with AoA.  We only use airspeed as a proxy indication of AoA, but that only works under 1g.  A surprising number of pilots still don't understand this.  I really think we've dumbed down flight training too much over the years, in an effort to make learning to fly less scary and more accessible.  Removing spins from the private pilot syllabus was a terrible idea.

Any airplane can be stalled at any airspeed, in any attitude.  The only thing that causes a wing to stall is exceeding the critical angle of attack.  There's no such thing as an airplane that cannot be stalled.  That's neat, that under 1g, the Antonov elevator doesn't have the authority to exceed the critical AoA... Under a different load factor, it certainly does - and these are the conditions in which an inadvertent stall usually occurs.

None of this has anything really to do with drag, other than the fact that all the features that make the AN-2 able to fly slowly actually add drag to it.  Just looking at it, you can tell that it should be slow (it is), and that it should come down steeply while maintaining a given airspeed without power.

I was referring to 1g stall (in case in cannot be stalled). Just FYI I did spins , have science degree and flight instructor certificate . Vs0 is not published in AN-2 Russian POH for a reason. Probably same reason we don't have VG diagram in 172 POH.

I can  I also ate a case one can cause structural damage before stalling, but we not talking about it. AN-2 aerodynamically cannot be completely stalled at 1G

 If I remember correctly Antonov 2 alpha is around 24 degrees . What about Sterman? I would guess around 11-15 degrees?


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26 minutes ago, Stearmandriver said:

None of this has anything really to do with drag, other than the fact that all the features that make the AN-2 able to fly slowly actually add drag to it.  Just looking at it, you can tell that it should be slow (it is), and that it should come down steeply while maintaining a given airspeed without power.

I am by no means an expert but could the weight make a difference for the plane not slowing down. By default the plane has 9 pax,100 Kg each (while there only 7 seats 🙂 ) On my first flight I kept only 3 pax (80Kg each) and I could dive it easily towards the runway treshold with max flaps. This was the gps version btw.

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9 minutes ago, sd_flyer said:

AN-2 aerodynamically cannot be completely stalled at 1G

I still would disagree with this depending on pitch attitude of maneuver entry, but ok, let's take it at face value.

The claim I responded to was "the airplane cannot be inadvertently stalled.". How many inadvertent stalls actually occur under 1.0g?  Almost none, I'd say.  Take the classic example of the overshoot / wrapped up / probably cross controlled base-to-final stall-spin accident scenario:. It would never happen at 1g, right?  We wouldn't even have a name for it.

Airplanes spend a lot of time at load factors others than 1.0g; pilots should understand that all those airspeeds published in their manuals relating to stalls don't apply at these times.  I highly, highly recommend an upset prevention and recovery course for all pilots, unless you've already got significant aerobatic experience.  It's amazing how eye opening that can be for folks.

But still... An interesting discussion that I always love, but still doesn't have anything to do with the amount of drag on an AN-2.  😉


Andrew Crowley

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3 minutes ago, Gerwil said:

I am by no means an expert but could the weight make a difference for the plane not slowing down. By default the plane has 9 pax,100 Kg each (while there only 7 seats 🙂 ) On my first flight I kept only 3 pax (80Kg each) and I could dive it easily towards the runway treshold with max flaps. This was the gps version btw.

 

Load effects the airspeed you descend at but has no effect on the glide slope.

A heavier aircraft will travel to the same point on the ground at best glide but will get there quicker.

Edited by Glenn Fitzpatrick

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3 minutes ago, Gerwil said:

I am by no means an expert but could the weight make a difference for the plane not slowing down. By default the plane has 9 pax,100 Kg each (while there only 7 seats 🙂 ) On my first flight I kept only 3 pax (80Kg each) and I could dive it easily towards the runway treshold with max flaps. This was the gps version btw.

To a small extent, but there are no weights that this plane shouldn't be noticably draggy at, so that's probably not it.

Note that I don't have the plane in MSFS and don't know how it actually performs in the sim; I'm just responding to the observations of others that it seems difficult to slow down.  I really don't think that, compared to the average GA aircraft, this thing should seem difficult to slow down ;).


Andrew Crowley

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10 minutes ago, Stearmandriver said:

I still would disagree with this depending on pitch attitude of maneuver entry, but ok, let's take it at face value.

The claim I responded to was "the airplane cannot be inadvertently stalled.". How many inadvertent stalls actually occur under 1.0g?  Almost none, I'd say.  Take the classic example of the overshoot / wrapped up / probably cross controlled base-to-final stall-spin accident scenario:. It would never happen at 1g, right?  We wouldn't even have a name for it.

Airplanes spend a lot of time at load factors others than 1.0g; pilots should understand that all those airspeeds published in their manuals relating to stalls don't apply at these times.  I highly, highly recommend an upset prevention and recovery course for all pilots, unless you've already got significant aerobatic experience.  It's amazing how eye opening that can be for folks.

But still... An interesting discussion that I always love, but still doesn't have anything to do with the amount of drag on an AN-2.  😉

Oh more than 1 G ? There are plenty of those!

Here another. Departure cross-control stall/density altitude

https://www.youtube.com/live/4_7pjDzPfG0?feature=share

 

The airplane has amazing controllability - display below. Except for Western trained pilot it is "more left rudder" and in case of Antonov more left. I suspect accident in Wilton, CA was muscle memory of right rudder. 

 


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Another interesting fact. Here is an old photo of Antonov's team that design and build An-2. Bottom row fourth person from the left is Antonov himself. Top row, fourth person from the left is my grandpa. He was in charge of building team. 

09s05_antonov2.jpg?width=1024&height=720

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