how do your stalls break?

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yanknbank
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how do your stalls break?

Post by yanknbank »

M5-210c, vortex generators. Did some show flight and stall familiarity. Flaps down, stall breaks at about 35mph indicated. I'm guessing around 45 calibrated. During slow flight, it's very docile and maneuverable, but the break itself is a pretty sudden left wing drop. Recovery is a non event.

How do yours break? Dead ahead? Falling leaf?

Plane flies without input nice and straight, so I'm not sure where to look at rigging. It does the same flaps up. I'll check the washout.

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Re: how do your stalls break?

Post by Cash »

If your plane flys nice and straight, don’t change anything. It’s very common for an airplane to stall left wing first with no rudder input. There’s more 100 series Cessna out there than any other airplane and most all will drop the left wing first. When stalls just use some right aileron and be glad your plan flys straight. Not all do.
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yanknbank
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Re: how do your stalls break?

Post by yanknbank »

I agree with you about most planes. I guess I ask because of the reports of others having a nice clean forward break with their maule. The Cessna I believe uses a differential washout on the left wing to counter for the torque and slip stream in flight. The maule seems to require symmetrical wash, so the left wing shouldn't necessarily stall first on this plane. I don't think using right aileron is going to be a good solution though. That might invite more pucker than I'm capable of providing. I still need to take measurements.

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Mog
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Re: how do your stalls break?

Post by Mog »

Mine just starts sinking assuming flaps out. No break or significant buffeting really. You can stear it around pretty aggressively with the rudder. I have reduced dihedral and droop tips with vortex generators.

yanknbank
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Re: how do your stalls break?

Post by yanknbank »

Thanks. I'm wondering about maybe needing to adjust the left flap up a little. As I see my notes now, I never took it to full stall flaps up, so I don't know if it breaks poorly with them up. These ideas only ever seen to come to me when I'm away for weeks...

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Re: how do your stalls break?

Post by Kirk »

I agree that if it flies straight the rigging of the wings “should” be good. Maybe have it checked at next annual, fairly straightforward to check but very much a step by step process to correct. Worth taking it to the break with flaps up (at a safe altitude) to see if the problem persists in that configuration.

If the problem is flaps, you might find it on the ground by setting the flaps to full down then pressing the flaps towards up with your hands to simulate an air load. Check to see if the flaps have an equal amount of slop or play when pushed up, measure the angle to see if they are correct and match. If there is a difference, check the rod ends, pulleys etc all the way up the system and have the flaps rigged if the angles mismatch.

Any misshapen fairings, odd skin wrinkles or previous repairs on the wing? Amazing how a small imperfection can disrupt stall progression.

Look at both ailerons and flaps to see if any have developed a twist. Seen that from being parked in high winds with control locks on or deploying flaps at too high a speed.

Lastly, are you sure you were in coordinated flight when you tried it? Kind of a challenge sometimes to keep the ball in the center with the nose way high and control effectiveness falling off.

Personally, picking up a wing from a stall break, I primarily use rudder, though the Maule spoils us by the ailerons being effective right into a full stall. Love these planes!


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montana maule
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Re: how do your stalls break?

Post by montana maule »

A few comments on the above posts. The aerodynamics of flight is a complicated subject. What happens at the moment of a stall is not as simple as we think. Since chapters in books are written on the subject it can't be covered here. I would direct you to the following." Airplane Flying Handbook" FAA-H-8083-3 ch.5, "Stick and Rudder" by Wolfgang Langewiesche, and any of the "Flight Manuals" by William K Kershner.

A few thoughts to consider -
1. If the aircraft is rigged correctly and flys true and straight in cruise I would not suspect the wing rigging. The aircraft is rigged for the "normal" flight envelope. Unless you are an aerobatic pilot in a certified aerobatic airplane you will spend 99.99% of your time in that part of the envelop. Both of my Maules will mush down, wings level right at the stall. If forced into a deeper stall at some point the rudder becomes ineffective and a wing will drop. Because of aerodynamic aspects of the aircraft it will most likely be to the left.
2. Does the rudder travel to the stops and are they set correctly and is the pilot moving them to the stops?. Even in a normal stall the Maule rudder is effective in combatting yaw. Which is the correct response to a wing dropping and the start of a spin not opposite aileron. Kershner - "When the stall break occurs, the roll will be rapid. Neutralize the ailerons, stop any further rotation with opposite rudder as you relax the back pressure." That is the reason for the rudder/aileron interconnect on Maules. ( You do know that the small movable tab on the rudder is not a rudder trim.) It is a safety device for the pilot that tries to use aileron only to recover from a wing drop and an incipient spin. When using right aileron to stop a left wing drop the interconnect applies right rudder ( the correct response) even if the pilot does not. The opposite scenario for a right wing drop.
3. Another possibility is a wrong stop setting on the elevator. As a safety feature the up stop is set so that the airplane will not enter into a "deep" stall. In that severe of an angle of attack the rudder can lose effectiveness and not be able to counteract yaw which will lead to one wing stalling first and wing dropping.

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Re: how do your stalls break?

Post by yanknbank »

Thanks for that Montana. You aren't the first to suggest kershners books, so I should probably take a look. I am a cfii atp, and despite spending too much time in the air transport world, am still pretty familiar with the academics of aerodynamics. I am however very new to maules and their design characteristics. (I usually head to Kalispell with my pacer to visit a friend every year, I'd love to take some instruction from you next time I'm in that area).

I'd like my stall characteristics to be a little more benign if I can, for as you know, passing through some of the terrain on the way to a very short field can yield sone unfavorable drafts, and if on that unlucky day it's enough to induce a stall, if rather it not drop it's wing that fast and put me in the trees. This was quite aggressive, more than any ga plane I've experienced. Admittedly, it was a power on effort, so engine torque was aiding the roll, but many approaches will be power on. This break is far too fast to use rudder for directional control. It's just enough to recover while pointing in the general vicinity of the break, but there's no controlling it.

I'll look into the elevator stops. If this is what a maule does, so be it, but if I can improve it, I'd like to. I'm sure you can tell from my other posts that this plane is going to be a project of sorts. I'm still very interested in looking at my flaps down deflectionb angles.

Related question. How slow can y'all fly before it breaks? Asi and groundspeed if you know it.

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Re: how do your stalls break?

Post by Kirk »

What you’re describing sounds out of the normal realm of stall in a Maule.

Checking elevator travel does sound like a good idea. With any kind of power added mine will just buffet and mush straight ahead all day long as long as it is coordinated. IAS well, way low, 40 mph or less with full flaps. I never really look when practicing stalls. It varies so much depending upon power on or off, accelerated or not etc.

I’m guessing flaps misrigged or excess elevator travel as the top 2 candidates if you are in coordinated flight.

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Mog
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Re: how do your stalls break?

Post by Mog »

I don't know your model, but my M4 220C basically doesn’t “stall” power on. Well, that’s a lie but basically I can keep it wings level and not loose an inch of altitude. The plane will be way way tail low. Again this is just my particular airplane, but I can cruise along happily at say 1/4 to 1/2 power all day long without loosing altitude or dropping a wing. This is well below typical stall speeds and is frankly only safe at altitude.

yanknbank
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Re: how do your stalls break?

Post by yanknbank »

This is all very helpful, thank you.

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gdflys
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Re: how do your stalls break?

Post by gdflys »

The power on/high statement is the key. You have all the left turning tendencies everyone typically knows plus others like the spiralling slip stream and propwash increasing the angle of attack on the left wing root area and decreasing it on the right wing root area, torque roll effect at very low speeds, rudder stall etc. There's a reason many aircraft manuals have power to idle for a spin recovery and it's because of all these left turning effects. You can get much slower or deeper into the stall behind the power curve at high power and all the controls are less effective than at normal power off stall speeds.
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AndrewK
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Re: how do your stalls break?

Post by AndrewK »

Going to add my recent experience with this topic since I have a similar power OFF stall characteristic (break to the left) now, but used to mush with wings level.

Little background on my M5-235C with VGs: The plane had been a little right wing heavy in cruise, seemed consistent across different weights, loading, fuel left vs right, etc. The elevator horns were also a little uneven causing a little more up elevator on the right leading me to think that maybe this was causing the plane to twist to the right causing the heavy right wing. It's been like this for as long as I can remember but otherwise it flew great and my full stalls were a wings-level mush, no break. But still the heavy right wing started to bother me so not being able to leave "good enough" alone and since it SHOULD fly balanced I decided to check the rigging and see if I can get it corrected.

With Maule manual in hand, the plane was levelled and rigging checked out. Dihedral was a little lower on both wings than the manual calls for otherwise the elevator was needing adjustment and my flaps had some slop. With the elevator out of balance, one side was exceeding the max deflection but now can't recall which direction. Had the elevator horns balanced but could not get perfect without some extra persuasion so decided to just try it our and see if we were at least on the right track. At the same time all the hardware in the flaps was replaced to reduce the slop and the flaps needed a little adjusting afterwards.

Now with the elevator and flap adjustment only, the plane flies a little less right-wing heavy but stalls with a noticable break to the left. I am glad to see that this is common in aviation but since my plane used to not break and remained wings-level that is what I would like to get back to so will be going back in for more adjustments soon, start at step 1 again and go word by word. In hindsight I wish I had one adjustment done at a time to rule out either the elevator or flaps but too late. I also don't recall trying this with no flaps so either way there is some work to do.

Not sure if this helps or just adds another wrinkle to it all.

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crbnunit
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Re: how do your stalls break?

Post by crbnunit »

Honestly, with the VG's the M4 just mushes. I like to use that tendency if I am high on approach. Just lift the nose a bit and mush it to where I need to be. A blip of throttle is all that is needed for recovery. It will "break" if I push it far enough into stall but is really benign and easily controllable. I too drop the left wing with a full break. A little right rudder brings it right back to level and drop the nose/add power for recovery.

Power-on stalls are a bit frightening. Mellow but having the nose that high is a bit unnerving!
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Re: how do your stalls break?

Post by andy »

MX-7-180 with vortex generators and 30'10" wing. Mine usually mushes in a stall. I did a performance card for it in 2016 when I did stalls in all flap configurations with McCall Mountain Canyon Flying Seminars a bit south of KMYL airport at 7,500 MSL. With 48 degrees flaps it stalled at 35 mph.

https://www.maulepilot.com/img_1378.jpg
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