So... Whats this rudder for? (Full Version)

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teookie -> So... Whats this rudder for? (9/8/2006 5:14 AM)

So I'm getting into flying again. Been getting my skills back by flying a tower uproar. Even though this is a "sport" model, and should (I believe) require at least a little rudder to fly well, I still seem to only use it when taxing and landing. I know it's important for aerobatics and cross winds, but what about a basic turn? Is there a more advanced technique than the bank and pull up routine? Just wondering especially since my last plane was an aero-star 40 with oodles of dihedral and a flat airfoil -- quite a bit different from the uproar. I'm assuming there is more for me to learn... so lets have it!! What's the rudder for? [8|]



KidEpoxy -> RE: So... Whats this rudder for? (9/8/2006 5:41 AM)

Spin Recovery?



chickenx5 -> RE: So... Whats this rudder for? (9/8/2006 5:58 AM)

turns look better with rudder, if you dont use it the tail looks like its sagging down.



JPGale -> RE: So... Whats this rudder for? (9/8/2006 8:24 AM)

As chickenx5 said the turns look better. In full scale these are called co-ordinated turns. What happens is that the back of the plane is turned as well by the rudder.



ArCeeFlyer -> RE: So... Whats this rudder for? (9/8/2006 9:08 AM)

Just to name a few basics needing rudder. Flat turns, Knife edges, snap rolls, spins, flat spins, side slipping, cleaner course corrections in looping maneuvers, stall turns and wing overs, wild donuts on the ground [:D], and of course, crosswind landings and takeoff, and those turns look so much better and to me even feel better. If you ever get into helicopters, especially with a head lock gyro, the co-ordinated turn is a must. Just keep practicing using the rudder as much as possible and eventually you won't even have to think about it. It really opens up a bigger world of flying.



PlaneHeli -> RE: So... Whats this rudder for? (9/8/2006 9:28 AM)

As has been mentioned. In full sized aircraft rudder use is a must.

To roll to the left, the left aileron moves up / the right aileron moves down. This results in more drag on the right wing, thence the aircraft yaws to the right. Looks very untidy and your passengers will feel sick in no time.

Slight rudder is also required during a step turn. If it is unbalanced or opposite rudder held in the aircraft can violently flick in the opposte direction of the turn. (Ive seen it happen. very scarey)

So more rudder required while rolling into a turn, slight rudder while maintaining the turn, then rudder required when rolling wings level.

Rudder also used to yaw the aircraft straight before touchdown when landing in crosswind.

http://www.veoh.com/videoDetails.html?v=e33274

Notice only the last couple of landings use rudder during the flare.
I believe this was part of the testing so they were intentionally landing without yawing the aircraft straight.



rwright142 -> RE: So... Whats this rudder for? (9/8/2006 11:51 AM)

Here is a snippet about one of the best flying technique books ever written, IMO:

"In the early 1940's, Wolfgang Langewiesche wrote a series of articles in Air Facts analyzing the various aspects of piloting techniques. Based on these articles, Langewiesche's classic work on the art of flying was published..."

The book is called "Stick and Rudder" and I bet you can get it at Amazon.com or other places too. In the book, Mr. Langewiesche puts more emphasis on the rudder than any other control surface. Good book.

Here is a link to more about the book:

Stick and Rudder



bubbagates -> RE: So... Whats this rudder for? (9/8/2006 12:56 PM)

Even though "Stick and Rudder" is more for full scale aircraft, it is a must read for any pilot, not matter what is being flown. This is a very old book and is still recommended for all new full scale students.

It does a very good job of explaining aerodynamic and control surface principals in a way that makes it very easy to read.

Up to this point, everyone has given you all kinds of things the rudder is for. One thing I will add is the rudder is the most powerful surface you have. Take a look at 100cc gas powered (not glow) and larger planes. you will always see more servos on the rudder than any other control surface.

As far as the video that was posted, that is a very good example of crosswind landing techniques, the only difference is at the last minute you use the rudder to yaw the plane to lineup with the runway. In the video they were testing gear stresses.

Not too long ago we had a senior moderator here on RCU who's son worked on the gear on that plane. according to him, that video was shot in Washington state and on the 777 model, the tires were destroyed after the three tests they did that day, but the gear held up well and if I remember correctly they were in 30+ mph winds. Look closely at the rudder on 2 of the landings, you can easily see it moving quite a bit. I know I have seen that video several times over the last year and it always amazes me at the abuse that gear is taking

Could you imagine sitting in there as a passenger looking out your window and seeing the runway and you are flying sideways [X(]



MinnFlyer -> RE: So... Whats this rudder for? (9/8/2006 1:17 PM)

Well. I'll go against the grain here and say that for 90% of your flying you don't need the rudder.

Now, of course, every plane is different - A Cub with the full wing (Not Clipped) will show some noticeable Adverse Yaw while turning (Adverse Yaw is what caliber83 is referring to in his second paragraph). And the bigger the wingspan, the more noticeable it is.

But are coordinated turns necessary? In my opinion, no.

There are two big reasons why a full scale aircraft needs to coordinate turns: It reduces drag, which in turn saves fuel, and because with people in the plane, adverse yaw can bring on motion sickness. Also don't forget that Adverse Yaw is MUCH more pronounced in a Full Scale airplane due to the large wing.

In a small model (I say "Small" as compared to full size planes) the amount of fuel savings is minuscule - and there's nobody on board to get sick.

So it's only when I can ACTUALLY SEE adverse yaw happening that I will correct with a little (and I do mean LITTLE) rudder. And again, this is usually only on Floaters with a huge wingspan like a Full-Wing Cub



rwright142 -> RE: So... Whats this rudder for? (9/8/2006 1:33 PM)

Minnflyer,

You are absolutely right; the rudder is not needed. When I was first trained I was told to ignore it until I was more comfortable with 'regular' flying. However, I soon developed the bad habit of using the ailerons to correct the lining up of my approaches. I have been practicing with the rudder now for several flights and I like using it; especially for the approaches.

So, do you need to learn the rudder? Not if you just enjoy the basic maneuvers. But for practicing coordinated turns, straight approaches in wind, and for many 3D maneuvers you do. Although I do not do 3D I like to have my Cessna do nice straight rolls, but I really like having her come in for a straight and level landing. I know many of you can do the same thing without it, but I just like the challenge and learning more about how to fly the plane. To me, it's like having a plane with flaps. You don't need them but it's just one more thing that you can play with. I have flaperons on my Cessna and although I want flaps eventually, I have been playing with them along with the rudder. It's just one more level of experience that I enjoy learning.


Bubbagates,
As for "Stick and Rudder", I should have mentioned it was for Full Scale - thanks for your input on that.






bubbagates -> RE: So... Whats this rudder for? (9/8/2006 1:49 PM)

quote:

ORIGINAL: rwright142

Bubbagates,
As for "Stick and Rudder", I should have mentioned it was for Full Scale - thanks for your input on that.



I still have the exact same copy that I used when I was in full scale training many many moons ago. I still pick it up now and then to read it. Mainly I take it with me on long trips.



rwright142 -> RE: So... Whats this rudder for? (9/8/2006 1:59 PM)

Same here. It's even beside my bed on the night stand!
I find it amazing how it still applies today. When I was an instructor I handed it out to some students and every reaction was the same: very helpful.



PlaneHeli -> RE: So... Whats this rudder for? (9/8/2006 4:04 PM)

I agree with minnflyer.

Ive have tried it flying my model but notice very little difference. So I dont bother about it. Certainly larger scale slow flying models such as the cub may be required. Or for the precesion flying guys. Faster models you probably wouldnt notice the difference. It would be very difficult to know how much input to use, whereas full size aircraft have a specific instrument to indicate if its correct.

Im not sure what RC modellers are talking about when saying they use the rudder to line up their approach. You turn an aircraft using aileron with rudder to balance a turn (and roll). To line up using only rudder would be yawing the aircraft only (sideslipping) this is how to induce a wingdrop stall when at slow airspeed. This is also how you induce a spin during aerobatics. Very dangerous on approach to land at low altitude.

Id just use the rudder to yaw the model straight on landing if required.
If your into larger scale slow flying models, or precision flying. Then give it a go.




Jim_McIntyre -> RE: So... Whats this rudder for? (9/8/2006 4:17 PM)

Proper landing technique would have you using ailerons to maintain level flight while adjusting your heading (turn as you use it) with rudder. Using ailerons to bank during slow flight (e.g. landing) is not recommended as the induced drag and change in AOA of the can result in a tip stall.

I see far too many people avoid rudder for all the wrong reasons. The results are obvious, especially in a cross wind. landings at angles to the flight line which all too often endanger other flyers.

As for co-ordinated flight. It's true we don't have the instrument to co-ordinate perfectly but, with time you can see when someone makes an unco-ordinated turn, to me ot looks like the tail is dragging through the turn. Some simply mix in rudder with aileron this often results in the opposite effect with a slght slip (tail high) through turns.

Yes you can fly without rudder, my combat aircraft and my park flyer F16 don't even have one installed. But once you notice, you can't go back to "right stick only" flying. It just looks and feels wrong.



rwright142 -> RE: So... Whats this rudder for? (9/8/2006 4:17 PM)

quote:

ORIGINAL: caliber83
Im not sure what RC modellers are talking about when saying they use the rudder to line up their approach. You turn an aircraft using aileron with rudder to balance a turn (and roll). To line up using only rudder would be yawing the aircraft only (sideslipping) this is how to induce a wingdrop stall when at slow airspeed.


When I mentioned using the rudder for lining up my approach, I am referring to making the approach straight in reference to the runway. I use the ailerons to maintain a level approach and throttle for rate of descent. I use the rudder to sideslip in a crosswind or to make sure I am coming in straight. For example, taildraggers use the rudder to make sure they take off straight down the runway (once the tailwheel is up) - same principle, just on landing.

I hope I explained that well. You are right, you don't need it, don't have to use it. I guess it's just a preference of mine.







doubledee -> RE: So... Whats this rudder for? (9/8/2006 7:07 PM)

Rudder application is an integral part of properly controlling an aircraft. The more maneuvers you do the more need to use rudder. Flying without using rudder, even for basic turns, is flying the aircraft in uncoordinated flight. Not only is it ugly, it is just plain sloppy flying.

Regards,
doubledee



exeter_acres -> RE: So... Whats this rudder for? (9/8/2006 7:21 PM)

as others have mentioned... just flying around and playing.. you can get away without using it much,,,
but, to fly well.. you need it all the time...
if you fly 3D, the rudder is used all the time.
I fly IMAC and there is hardly a second that I am not using the rudder.... (not always the correct way I might add![:'(])

IF you fly with the rudder, the flying looks more precise and smoother....



MinnFlyer -> RE: So... Whats this rudder for? (9/8/2006 8:34 PM)

quote:

ORIGINAL: doubledee

Flying without using rudder, even for basic turns, is flying the aircraft in uncoordinated flight. Not only is it ugly, it is just plain sloppy flying.



Well, I hate to disagree but... PHOOEY!

But this is not to say that KNOWING HOW to use your rudder isn't important!

Two weeks ago I had a left engine quit on a 90" P-38 and if I didn't have good rudder skills it would be a pile of sticks right now.



LT-40 -> RE: So... Whats this rudder for? (9/8/2006 10:54 PM)

I agree with MinnFlyer. I think that it is not nesecarry to use rudder for regular sport flying. However, I think that every good pilot should learn and know how to use the rudder. Even though it isn't used much, you will be glad that you know how to use it when you really need it. Rudder can be very important on take offs landings and depending apon the wind dirrection. Rudder is also needed for alot of aerobatics. Just learn how to use it and you wont be sorry!



ArCeeFlyer -> RE: So... Whats this rudder for? (9/8/2006 11:51 PM)

Well put LT-40. That's it in a nutshell. In R/C sport flying the main thing is to have fun and if one is happy flying at a limited skill level, then have fun. If one is on a quest to heighten their skill level, then learn all the controls you can, and still have fun. Of course, one should try to reach a level that allows one to fly safely as well.



PilotFighter -> RE: So... Whats this rudder for? (9/9/2006 5:49 AM)

When I fly a loop, I don't just do a small loop. I fly really big loops with 40 size planes. I'm talking loops that are 5 or 6 hundred feet in diameter. I enter on runway heading and I exit on runway heading at about the same point in space where the loop started and about eye level.
You can't fly a loop like that without using rudder to make tiny corrections and to compensate for torque and p factor and precession and wind. How about hammer heads? How about slow roles that are 900 ft to 1000 ft long ? What about 4 point roles ? How about cross wind landings? Knife edges ? What if you need to slip the plane to loose altitude quickly on a dead stick ?

They put rudders on airplanes for a reason. There are maneuvers that rely heavily upon the use of the rudder. But almost all flying requires some rudder use, at least if you wish to do it correctly. IF you wish to get the most from your planes and this hobby, then I would recommend learning to use the rudder.
If you fly an aerobatic plane or if you fly a Piper Cub, the rudder separates the artisans from the hacks. [:D]



agexpert -> RE: So... Whats this rudder for? (9/9/2006 7:44 AM)

UM....

I have only been flying solo for 9 months now, but I fly every day. At first, I ignored that 'other' stick and was quite comfortable flying without it.....until I decided that flying every day meant flying in wind.

I don't think I could land in a crosswind without copious amounts of rudder input. Crabbing, slipping and flat turns are all basic maneuvers which require rudder. Learning to use rudder properly has been the most useful flying skill I have learned since my solo. Most of the IMAC guys I fly with will wear out the rudder/throttle stick pot after only a few seasons....long before the aileron/elevator pot. (Almost everyone in CA flies mode 2).

The best way to get into flying rudder and training your mind to react with rudder is to learn to hover. I spent almost 2 months learning to hover with a 3D foamy. After that, rudder becomes more instinctual. It's just a way to steer the back of the plane.

Although you can fly without it, I think it opens a whole new world of flying once you learn it's value. You can successfully drive a car without turning left, but it takes almost twice as long to get anywhere.



sigrun -> RE: So... Whats this rudder for? (9/9/2006 8:08 AM)

quote:

ORIGINAL: teookie
... so lets have it!! What's the rudder for? [8|]

Co-ordinated turns for one. It can be easily observed can see if someone is slipping or skidding into a turn, it's just that at your re-newbie stage, you don't discern it. It's very easy to spot someone flying around without using rudder.

Maintaining runway heading as track after takeoff. Notice how so many people mindlessly just drift left with torque allowing the model to fly them instead of the othwer way round invariably going with it in a left hand climbing turn? If they used rudder for other than taxi-ing and keeping straight on the ground they wouldn't.

Rudder is also necessary to execute many aerobatic manoeuvres with precision, eg: the humble loop, and you'd have diffulty doing either knife edge or a stall turn without it. it's always required in a slow roll if the model has some dihedral induced coupling. Strangely enough, in most models, aileron is usually more important than rudder in spin initiation and stabilisation.

Then there's crosswind landing technique.

Look, for sure you can turn and bank the model without rudder wrestling it into the air and onto the ground, it's just that it is observable and understood as sloppy flying regardless of the excuse proffered. If that doesn't bother you, then it doesn't bother you.....but it doesn't alter the fact.



Jim_McIntyre -> RE: So... Whats this rudder for? (9/19/2006 9:38 PM)

quote:

ORIGINAL: teookie
What's the rudder for? [8|]


Yaw.... [:D]

Yes, you can sport fly without it ... with a well behaved sport plane.... on reasonably calm days or with wind direction down the field or from especially from wide runways.... [:D]



hogflyer -> RE: So... Whats this rudder for? (9/19/2006 10:52 PM)

Here’s a good example of knowing the proper use of the rudder. I was training a student on his Hanger 9 Alpha when he finally fatigued, giving me the plane back. As I was heading up wind over the the runway to set up my downwind pattern I decided to do a couple of loops before the cross wind turn. As I entered a third loop and was pulling to vertical, at about 50’ the engine quits (ran out of fuel). I hit the rudder into a sort of stall turn at about 70 deg nose up, pulled the plane out flying down wind and circled for a landing right in front of me. Had I not known how to use that rudder and entered a stall turn, either the plane would have been re-kitted from a stall or my student would have had a long walk. This was also not something I thought about, but an instinctive reaction in an unusual flight attitude - what is the quickest and safest route to setting up a stabilized dead stick glide.

I also had the aileron linkage disconnect on my NextStar while giving instruction and had to bring the plane back using only rudder – that one really freaked the student out, but he learned very quickly the importance of knowing how to properly use every control on the plane.

Hogflyer



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