Questions about using yawing and tip stalls

[SkyEye]

Many planes, especially beginner RC planes can be flown without using rudder. That said, understanding rudder and using it will make you a better pilot; opening up new options like flying knife edge; making flat turns in gliders to conserve altitude; flying scale aircraft, especially WW I and II vintage; side-slipping to lose altitude quickly for small landing areas; and landing in strong crosswinds.

About tip-stalls: most people use the term incorrectly. Most people use the term "tip-stall" to refer to an aircraft's tendency to drop a wingtip when it stalls. This is just a stall. Many aircraft will drop a wingtip when they stall. In a properly designed wing the root of the wing will stall first and the stalled portion moves out toward the wingtip as the plane slows. Usually the wing will stop generating enough lift to hold the aircraft up before the stall propagates all the way to the tip. If you can keep the wingtips generating lift even at high angles of attack the aircraft will stay controllable throughout the stall and recover relatively easily.

In contrast, a tip stall is when the wing tip stalls before the root of the wing, making for violent and unpredictable stall behavior. If your airplane is tip stalling, it is a flaw in the design. Many FT planes have under-cambered wingtips because under-cambered airfoils stall at a higher angle of attack than flat-bottomed airfoils; this keeps the wingtips generating lift and control even when the rest of the wing has stalled.

Flight simulators generally do a bad job of simulating stall behavior. Stalls are usually very docile in flight sims. Accelerated stalls, such as when you pull sharply out of a dive, are rarely simulated. Flight sims also do a bad job simulating side-slips and forward slips, but that's not what you were asking about.

Thank you for all of that info. That's a reason why I wanted to learn about using rudder, scale flight, altitude conservation and just to see how it works. I was also wondering about slips and stuff in sims so you clarified that for me.

To combat adverse yaw, no. Check out this video on it to better understand adverse yaw:

There are some situations in which you would use opposite rudder compared to the ailerons, but they are usually more special things like knife edge or slipping.

Thank you for the video. Very helpful.

I always coordinate turns. It becomes instinctive.

Rudder is an invaluable control surface on any aircraft, from an Airbus A380, to a tiny 4 channel R/C plane. While most airliners can fly “feet flat on the floor” because flight computers coordinate turns for you - but on landing rudders are always used. Likewise, with any single engine propeller aircraft (any size) - P-factor in a climb induces “left turn” tendency requiring right rudder on every climb.

Thanks, I had always wondered about that. All of these aeronautical concepts that I had always heard mentioned but didn't understand. In the few days I've been practicing with rudder in my turns I've gotten pretty used to it.

One more unrelated question. This might take a while to answer. You know how commercial pilots land main wheels first and then slowly put the nose down? I have been trying to practice landings like that but I find it very difficult and I need to set up a golden glide slope. Is it supposed to be that difficult? What's the best way to approach it. Again, its only for commercial pilots to make the flight smoother. I have no problem with my typical landing style where I cut the throttle and sort of hope for the best. I have learned to manage my throttle better in general which has helped my landings a lot. Back then I would just either go full throttle or cut it...

 

[CappyAmeric]

One more unrelated question. This might take a while to answer. You know how commercial pilots land main wheels first and then slowly put the nose down? I have been trying to practice landings like that but I find it very difficult and I need to set up a golden glide slope. Is it supposed to be that difficult? What's the best way to approach it. Again, its only for commercial pilots to make the flight smoother. I have no problem with my typical landing style where I cut the throttle and sort of hope for the best. I have learned to manage my throttle better in general which has helped my landings a lot. Back then I would just either go full throttle or cut it...

Most commercial aircraft are touching down slightly below VREF speed which is a percentage of stall speed. That speed gives the appropriate pitch attitude which has the nose high, so only a slight flare (pitch up) is needed. At main gear touchdown, there is little if any flying speed left so the mains stay stuck - that often causes a pitch forward moment in most large aircraft, and the pilot is then able to pull back on the stick to gently ease the nose gear down as reverses are deployed.

An R/C plane should work the same on landing as a large aircraft, however, you rarely have exactly the right speed or descent rate. Airliners land at precise speeds and descent rates for their current weight and adjust VREF speed for wind, including gusts. With R/C, we are essentially guessing on speed, descent rate, etc. In many cases, if you tried to “ease the nose gear down“ after main gear touchdown, you would get airborne again. As you have learned, on most R/C planes, once you are in ground effect (half the measurement of the wingspan, above the ground), just ease the power off if it isn’t already, and slowly keep pulling back on elevator until mains touch, then don’t worry too much about jarring “the passengers“ with the nose gear dropping.

 

[L Edge]

Thank you for all of that info. That's a reason why I wanted to learn about using rudder, scale flight, altitude conservation and just to see how it works. I was also wondering about slips and stuff in sims so you clarified that for me.


Thank you for the video. Very helpful.

Thanks, I had always wondered about that. All of these aeronautical concepts that I had always heard mentioned but didn't understand. In the few days I've been practicing with rudder in my turns I've gotten pretty used to it.

One more unrelated question. This might take a while to answer. You know how commercial pilots land main wheels first and then slowly put the nose down? I have been trying to practice landings like that but I find it very difficult and I need to set up a golden glide slope. Is it supposed to be that difficult? What's the best way to approach it. Again, its only for commercial pilots to make the flight smoother. I have no problem with my typical landing style where I cut the throttle and sort of hope for the best. I have learned to manage my throttle better in general which has helped my landings a lot. Back then I would just either go full throttle or cut it...

First of all, I am glad that you are trying to use the rudder in all situations. The amount of rudder depends on the design of the airplane. Bipes need it to really control movement. Knife edges, rolling circles, 3D flying are samples showing the need to control the rudder. So, the more you use it, you will add acrobatic skills to your toolbox.

The one big thing others left out is using rudder on takeoff (crosswinds, nosewheel sterring, etc) for the big warbirds. Most pilots just set the bird down, apply full power, (wing has a high angle of attack) and rather than gain speed(lifting the tail up and get the wing horizontal) just let it take off so it ends up rolling over and crashing. How about a bounce landing with a warbird? If you don't adjust power, elevator, and correct rudder, it will be damaged. Do it right, correct rudder amount will save you. What you need to do is go up 3 crash heights and apply yaw and see what happens to roll and pitch. Put a plane near a stall condition, add rudder and adjust elevator/aileron/throttle to fly it level to survive.

Here is a sample of rudder helping. One aileron servo crapped out (positiondown on the wing) Long story short- used rudder, elevator other aileron, throttle and landed safely.

Now to your unrealted question-- Yes you can by doing two things. The first is a slow moving airplane that has either flaps or flaperons.
The second is to go into the throttle curve and for the 1/3, you flatten the curve so you have little thrust change for movement of the throttle stick. Then try landing where you flare and when your main gear touches, you throttle up/down to keep it moving nose off and then back down to have nose wheel touch. It's throttle management,skill and a lot of luck.
I use a transport(have a shuttle on it) and every so often I can do it.

Hope this make sense. If not, ask away.

 

[Bricks]

A good way for better landings and takes some getting used to is use the elevator to control landing speed hold elevator steady, then use throttle for controlling your altitude.

 

[SkyEye]

Most commercial aircraft are touching down slightly below VREF speed which is a percentage of stall speed. That speed gives the appropriate pitch attitude which has the nose high, so only a slight flare (pitch up) is needed. At main gear touchdown, there is little if any flying speed left so the mains stay stuck - that often causes a pitch forward moment in most large aircraft, and the pilot is then able to pull back on the stick to gently ease the nose gear down as reverses are deployed.

An R/C plane should work the same on landing as a large aircraft, however, you rarely have exactly the right speed or descent rate. Airliners land at precise speeds and descent rates for their current weight and adjust VREF speed for wind, including gusts. With R/C, we are essentially guessing on speed, descent rate, etc. In many cases, if you tried to “ease the nose gear down“ after main gear touchdown, you would get airborne again. As you have learned, on most R/C planes, once you are in ground effect (half the measurement of the wingspan, above the ground), just ease the power off if it isn’t already, and slowly keep pulling back on elevator until mains touch, then don’t worry too much about jarring “the passengers“ with the nose gear dropping.

Thank you, that helps a lot. Learning low/stall speed characteristics about different models sure helps.

First of all, I am glad that you are trying to use the rudder in all situations. The amount of rudder depends on the design of the airplane. Bipes need it to really control movement. Knife edges, rolling circles, 3D flying are samples showing the need to control the rudder. So, the more you use it, you will add acrobatic skills to your toolbox.

The one big thing others left out is using rudder on takeoff (crosswinds, nosewheel sterring, etc) for the big warbirds. Most pilots just set the bird down, apply full power, (wing has a high angle of attack) and rather than gain speed(lifting the tail up and get the wing horizontal) just let it take off so it ends up rolling over and crashing. How about a bounce landing with a warbird? If you don't adjust power, elevator, and correct rudder, it will be damaged. Do it right, correct rudder amount will save you. What you need to do is go up 3 crash heights and apply yaw and see what happens to roll and pitch. Put a plane near a stall condition, add rudder and adjust elevator/aileron/throttle to fly it level to survive.

Here is a sample of rudder helping. One aileron servo crapped out (positiondown on the wing) Long story short- used rudder, elevator other aileron, throttle and landed safely.

Now to your unrealted question-- Yes you can by doing two things. The first is a slow moving airplane that has either flaps or flaperons.
The second is to go into the throttle curve and for the 1/3, you flatten the curve so you have little thrust change for movement of the throttle stick. Then try landing where you flare and when your main gear touches, you throttle up/down to keep it moving nose off and then back down to have nose wheel touch. It's throttle management,skill and a lot of luck.
I use a transport(have a shuttle on it) and every so often I can do it.

Hope this make sense. If not, ask away.

Yes, that helps a lot. I'll practice that. I also didn't know about the rudder usage with warbirds so I'll keep that in mind.

A good way for better landings and takes some getting used to is use the elevator to control landing speed hold elevator steady, then use throttle for controlling your altitude.

That's how I'm able to do it sometimes but I think I just need more repetition to really get it down.

All good on questions. Thank you all! Happy flying.

 

[L Edge]

Skyeye:
Just keep doing your exploring on learning. Yes, use throttle management, use controls(yaw, pitch ailerons) use different planes(not all have the same flight environment) and you need to find the right motor/prop combo(for instance, you wouldn't use a high pitch like a 9in 6 pitch for try to grease landings it you use a 9 x 3/4).

So just experiment and get lots of flight time trying differences to see what works best.
If you want to push it learning to use rudder/throttle, build a bipe. Better yet, fly it inverted in a gusty wind. I use very little aileron, lots of elevator, rudder and throttle management. The plane is super in 3D hovering, knife edge, inverted flight, rolling circles, steep descents and close landings.

The purpose of the video is that if you didn't have usage of the rudder and throttle management, in the gusty wind, you will be sitting rather than flying.

 

[quorneng]

A glide approach, ground effect and flare. A rather extreme example but it does show the principle.

I would not be able to guarantee to do it every time!

 

[BayDesigns]

I’ll throw my 2 cents in here. I’m about to start taking full-scale flying lessons, provided my grades stay up. I’ve read a good bit of the required literature, and I’ll tell you that flying with rudder is definitely in your best interests. First of all, keeping your turns coordinated just looks better. Secondly, airplanes are prone to entering spins if stalled in uncoordinated flight- not a nice thing at low level and low speed on short final. Third, you’ll become a better pilot- you’ll have more command of the airplane through its entire flight envelope, and you’ll get a better sense of what it’s doing. You’ll also be able to pull of more maneuvers- intentional spins, knife edges, hammerheads, the list goes on. Even maneuvers that don’t REQUIRE rudder will look better. You’ll also be able to perform a forward slip- very useful when you want to loose serious altitude without gaining much speed. (Although, some aircraft do have issues if you attempt a forward slip with certain flap configurations- try this up high before you use it to clear those trees on final.) In the real world, taildragger pilots are usually regarded as the better pilots- and there’s a reason! They have to use the rudder more, and once a pilot learns to use rudder more effectively, they gain more control of the aircraft and more confidence in the air. So yeah, you can get away with not using rudder, but it’s available to you, so why not use it? You’ll be better for it.

 

[TheFlyingBrit]

I’ll throw my 2 cents in here. I’m about to start taking full-scale flying lessons, provided my grades stay up. I’ve read a good bit of the required literature, and I’ll tell you that flying with rudder is definitely in your best interests. First of all, keeping your turns coordinated just looks better. Secondly, airplanes are prone to entering spins if stalled in uncoordinated flight- not a nice thing at low level and low speed on short final. Third, you’ll become a better pilot- you’ll have more command of the airplane through its entire flight envelope, and you’ll get a better sense of what it’s doing. You’ll also be able to pull of more maneuvers- intentional spins, knife edges, hammerheads, the list goes on. Even maneuvers that don’t REQUIRE rudder will look better. You’ll also be able to perform a forward slip- very useful when you want to loose serious altitude without gaining much speed. (Although, some aircraft do have issues if you attempt a forward slip with certain flap configurations- try this up high before you use it to clear those trees on final.) In the real world, taildragger pilots are usually regarded as the better pilots- and there’s a reason! They have to use the rudder more, and once a pilot learns to use rudder more effectively, they gain more control of the aircraft and more confidence in the air. So yeah, you can get away with not using rudder, but it’s available to you, so why not use it? You’ll be better for it.

Excellent advice, I flew for years and only used rudder for take off and to taxi my aircraft. Now I use rudder all the time for landing and coordinated turns, if I can add rudder on a turn all better. It provides less drag and therefore less chance of a tip stall due to slower speeds.
It helps combat torque roll on take off too and as mentioned previously, its essential for cross wind landings. So don't underestimate the impact of rudder get it used

 

[Piotrsko]

Ummm, having owned a taildragger, you have to pay much more attention to what the plane is doing because everything leads to bad juju remarkably fast when you don't pay attention. That's why you're a better pilot. A Tri-pacer is a taildragger with an added nosewheel and the gear flipped backwards. In the air, it is exactly the same as a Pacer taildragger.

 

[TheFlyingBrit]

I started off with trike's when I first started learning many years ago, crashed into many wooly mammoths in those days. These days I am a tail dragger man, wouldn't thank you for a trike undercarriage these days.

 

[Piotrsko]

Never hit a woolie but them darned sabertooths liked to run off with the tires.

 

[Taildragger]

I started off with trike's when I first started learning many years ago, crashed into many wooly mammoths in those days. These days I am a tail dragger man, wouldn't thank you for a trike undercarriage these days.

Never hit a woolie but them darned sabertooths liked to run off with the tires.

Wow you guys are old.

 

[TheFlyingBrit]

Wow you guys are old.

Be careful us old guys can do a lot of damage with gums

 

[Piotrsko]

And I carry a very sharp and pointy witt.

 

[BayDesigns]

Ummm, having owned a taildragger, you have to pay much more attention to what the plane is doing because everything leads to bad juju remarkably fast when you don't pay attention. That's why you're a better pilot. A Tri-pacer is a taildragger with an added nosewheel and the gear flipped backward. In the air, it is exactly the same as a Pacer taildragger.

That's what I meant to say- I was having trouble figuring out a way to say it accurately. ¯\_(ツ)_/¯

 

[makattack]

Coincidental to this thread discussion, I've been immersed in the world of VR and IL2 Sturmovick Battle of Stalingrad with their livery of WW2 and WW1 planes over the Winter. I found that after multiple campaign missions where I used up all my ammo, without much damage to a single enemy fighter, and very hard / bouncy landings followed by ground loops or prop strikes at the end of these missions, I needed to go back to training. These videos, particularly the spin recovery videos are very informative and relevant to this discussion:

https://www.youtube.com/playlist?list=PLnyigzFtHeNqmQMVhq1Shl972CPX4O-0B

 

[danskis]

Aileron Differential - Gliders suffer a lot from adverse yaw especially in tight circles low to the ground where you're try to catch a thermal. On an RC glider, thanks to modern programming, you can use rudder or differential aileron. For differential aileron you program your radio so that ailerons go down less than they go up - creating less drag on the "down" aileron. Its not a universal solution, and you'll still fly better by being able to use your rudder but it is something to keep in mind. It made a huge difference in my DLG.

I did read somewhere that you shouldn't use it on your wing with elevons.