Cyclic and pedal

[LeftPedal]

Hi folks, I am reading this book about helicopter flying and I came across a statement that I do not understanding, will someone please clarify this for me.

 

"In fact, any change in collective or cyclic position will require you to adjust the pedals in order to

maintain co-ordinated flight."

 

I understand that moving the collective changes the torque that has to be compensated for, up collective, left pedal; down collective, right pedal assuming a counter-rotating rotor. What I do not know or understand is how the cyclic is affecting torque that you need to use the pedals, besides the fact that you might have to increase power and then you will need to adjust pedals.

[LeftPedal]

Hi folks, I am reading this book about helicopter flying and I came across a statement that I do not understanding, will someone please clarify this for me.

 

"In fact, any change in collective or cyclic position will require you to adjust the pedals in order to

maintain co-ordinated flight."

 

I understand that moving the collective changes the torque that has to be compensated for, up collective, left pedal; down collective, right pedal assuming a counter-rotating rotor. What I do not know or understand is how the cyclic is affecting torque that you need to use the pedals, besides the fact that you might have to increase power and then you will need to adjust pedals.

 

To clarify the question, why would moving the cyclic left or right cause the helicopter to yaw, I thought helicopters do not have adverse yaw as airplanes.

[Goldy]

To clarify the question, why would moving the cyclic left or right cause the helicopter to yaw, I thought helicopters do not have adverse yaw as airplanes.

 

 

Well, if I make a right turn(bank) using cyclic, am I not going to need some right pedal to keep the turn co-ordinated?

 

Yesterday I'm flying along alone in an R22. My rather large frame in the right seat flying along..and all is well. I notice the aircraft is not level, its banked low on my side due to my weight, yet the strings are straight. So I input some left cyclic to get the ship level, and guess what happens to the yaw? Yepp..more pedal now needed...even though the only control input made was cyclic.

 

Good reason to always have a 150 pound dummy to keep in the left seat, its easier to fly when the ship is a bit more balanced!

 

Which book are you reading..Wagtendonk ??(sic?)

 

Goldy

Edited December 31, 2007 by Goldy

[LeftPedal]

Goldy, I should have said that I do not have any flight hours in helicopters, I am interested in flying but at this time I am only reading articles, books, forums,etc . I guess my question seems rather basic but since I have never been in a helicopter every thing is foreign to me.

 

The book that I am reading is the Canadian Helicopter flight training maneuvers manual that I found on the internet. The paragraph is the last paragraph on Exercise Three --Effects of Controls under "Tail Rotor Pedals".

 

http://www.tc.gc.ca/civilaviation/general/...TP9982/menu.htm

[Goldy]

Goldy, I should have said that I do not have any flight hours in helicopters, I am interested in flying but at this time I am only reading articles, books, forums,etc . I guess my question seems rather basic but since I have never been in a helicopter every thing is foreign to me.

 

The book that I am reading is the Canadian Helicopter flight training maneuvers manual that I found on the internet. The paragraph is the last paragraph on Exercise Three --Effects of Controls under "Tail Rotor Pedals".

 

http://www.tc.gc.ca/civilaviation/general/...TP9982/menu.htm

 

Well, just think of it as a dance of balanced forces. Very delicate manuevers, but each change will effect another control. Little aft cyclic you slow down and start to climb, so if you want straight and level flight you need to reduce collective, which means more right pedal. I should have explained that many ships have a set of strings tied to the windshield...not very modern instrumentation but very cheap and effective. If the strings are both on one side of the aircraft in flight, you need to add pedal to get the strings to split....sort of a cheap mans ball slip/skid indicator.

 

I dont know that any of these are what the author had in mind, I guess I should go back and read the chapters on turning forces, but in reality you are always adjusting pedals to compensate for changes in throttle, collective, winds, etc..

 

Here's one for you to think about. Do I need to add pedal when I increase collective?

 

The answer is not always.....that should generate some lively debate...let the answers fly !

 

Goldy

Edited December 31, 2007 by Goldy

[blave!]

Not during an autorotation

[Gomer Pylot]

It depends a lot on the flight regime. Hover and cruise flight are different. If you're at a hover, moving the cyclic right or left will cause the rotor disk to tilt, and then move the aircraft to the right or left. That will cause the tail rotor effectiveness to change slightly, and thus require pedal movement to keep the nose pointed in the same direction. Moving the cyclic fore or aft will increase or decrease airspeed, with pretty much the same result. Most people don't notice the effect, because they're constantly moving the pedals anyway, and the effect isn't a large one. In flight, moving the cyclic fore or aft will also change airspeed, and require a slight movement of the pedals to stay in trim. Moving right or left, to enter a turn, does cause some adverse yaw, but the yaw goes away after the turn is entered, so the usual teaching is to not use pedals for turns. You can see the adverse yaw by watching the trim ball. If you're in trim, it's centered. Enter a turn and it moves, then comes back. If you have a turn needle, you can see it initially indicate a turn in the opposite direction. I think it's good practice to use pedal to enter a turn, then keep the ball centered. The effect is more noticeable in larger aircraft, rather small in smaller ones.

 

One thing to keep in mind is that any change to any control wil affect all the others to some extent. Everything is inter-related, and no control is an island, entire unto itself.

Edited December 31, 2007 by Gomer Pylot

[JDHelicopterPilot]

If you raise the collective there is an increase of power which is required to keep the main rotor spinning as fast is it should. (drag). With that incrase in power comes torque, which will cause the nose of the helicopter to turn slightly if not corrected for by the pedals.

 

If you move the cyclic forward to go faster you will lose altitude unless you raise the collective which as I said before means an increase in power. Again, the result would be a yaw (nose turns) unless corrected for by the pedals. The same would happen if you wanted to slow down. You would climb and so you lower the collective causing a reduction in torque and will be followed by a pedal change.

 

Turns in level flight require a small amount of pedal input but is barely noticed.

 

In short, a movement of one control requires a movement of all of them.

[Witch]

What I've noticed is that if you move any of the controls, you move all the controls. It's not really that noticable in a hover, but in flight it's a bit more noticable.

 

After a while, you don't even realize that you're moving the controls to compensate. It becomes like balancing on a bike after the trraining wheels come off-shaky at first, then automatic. You don't even know you're balancing.

 

Try to not think about where to move the controls while learning-especially hovering. Just let the force guide your actions young padawan.

 

Later

[Goldy]

If you raise the collective there is an increase of power

 

Your making an assumption here...be careful. How does raising the collective in a Bell 47 or an Enstrom 28 increasing power ?

[Goldy]

Not during an autorotation

 

Actually Blave..that was my point. Increasing throttle is what drives the need for more pedal,,not just raising the collective. Some helicopters increase power for you, and some don't. Minor point I know, but I wanted to make the guy think about it > !!

[Eric Hunt]

In forward flight you also have some slipstreaming effect, which unloads the tail rotor and uses less pedal. If you raise the nose, the speed decreases, the slipstream effect decreases, and the machine moves out of balance. You will need to adjust the pedals to get back into balance.

 

So, for cyclic, the primary effect is Attitude, the Desired Performance is airspeed, and the secondary effects are RRPM change, yaw change, gain of altitude. You want the desired performance, but you must adjust the other controls to minimise the secondary effects.

[skypilot011]

eric hunt is on the money, everytime you do one thing, you effect two others, no matter what control you are manipulating. this is why it is so extremely hard to learn to hover your first time.

[JDHelicopterPilot]

Hey Goldy how's it been? I fully understand the point you were making. I was not talking about autorotations or power off situations. I should have been more clear about that. Rather just keeping it simple for leftpedal to understand as I don't really know his knowledge level. In general rasing the collective when in powered flight will result in a power increase either by mechanical or pilot input.

 

 

Hope you had a great Holiday and New years.

[Goldy]

Hey Goldy how's it been? I fully understand the point you were making. I was not talking about autorotations or power off situations. I should have been more clear about that. Rather just keeping it simple for leftpedal to understand as I don't really know his knowledge level. In general rasing the collective when in powered flight will result in a power increase either by mechanical or pilot input.

 

 

Hope you had a great Holiday and New years.

 

Hey JD, hope you had a great holiday as well. My point wasnt really auto's...more that raising the collective does not in itself, increase power. On those ships with a governor or collator it certainly does, but on a 47 or a F28 all it does is change angle of attack...that was the point I was trying to make.

 

It's time for another attempt to get some LA VR members together for a fly in somewhere !!

 

Goldy

[JDHelicopterPilot]

Hey JD, hope you had a great holiday as well. My point wasnt really auto's...more that raising the collective does not in itself, increase power. On those ships with a governor or collator it certainly does, but on a 47 or a F28 all it does is change angle of attack...that was the point I was trying to make.

 

It's time for another attempt to get some LA VR members together for a fly in somewhere !!

 

Goldy

 

Point taken. Yeah, I'd love to meet up with you guys some time. One catch, I won't be a LA area pilot much longer. I am headed out to Vegas next week. Need to work more. Anyway, Keep me posted if you guys decide to do something. I will fly out several times in the plane. I know......what you're thinking, but the helicopter is just so expensive.

 

JD

[Goldy]

I am headed out to Vegas next week. Need to work more. JD

 

JD- How can Vegas have more work that L.A. ??

[JDHelicopterPilot]

JD- How can Vegas have more work that L.A. ??

 

Hey Goldy, good question. It's a bit of a drag. Well, where I work or worked I should say, was somewhat seasonal. I was paid daily and if there wasn't anything for me then I didn't go in. As a result some weeks I would work 2-3 days(winter, summer I worked more). Not enough in California. Looked around LA but decided pay VS cost of living just isn't good and I can do better elsewhere. That being Las Vegas which has tons going on with tours and some charters. It's just one of those things where I have to think of the family first. I am getting a nice pay increase and lower cost of living. I loved fly here and am very sad to go. I got to know a lot of pilots around here, most not in person but on the radio. I'll be back to vist though. LA is my roots in aviation, where I made that leap from CFI to flying Astars. It's been an awesome ride.

 

 

JD